diff --git a/Jakefile.js b/Jakefile.js
index 1f88ee39082..07a2ade06a6 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -105,6 +105,14 @@ var serverSources = [
     return path.join(serverDirectory, f);
 });
 
+var languageServiceLibrarySources = [
+    "editorServices.ts",
+    "protocol.d.ts",
+    "session.ts"
+].map(function (f) {
+    return path.join(serverDirectory, f);
+}).concat(servicesSources);
+
 var harnessSources = [
     "harness.ts",
     "sourceMapRecorder.ts",
@@ -361,7 +369,7 @@ compileFile(servicesFile, servicesSources,[builtLocalDirectory, copyright].conca
                 // Create the node definition file by replacing 'ts' module with '"typescript"' as a module.
                 jake.cpR(standaloneDefinitionsFile, nodeDefinitionsFile, {silent: true});
                 var definitionFileContents = fs.readFileSync(nodeDefinitionsFile).toString();
-                definitionFileContents = definitionFileContents.replace(/declare module ts/g, 'declare module "typescript"');
+                definitionFileContents = definitionFileContents.replace(/declare (namespace|module) ts/g, 'declare module "typescript"');
                 fs.writeFileSync(nodeDefinitionsFile, definitionFileContents);
             });
 
@@ -369,6 +377,20 @@ compileFile(servicesFile, servicesSources,[builtLocalDirectory, copyright].conca
 var serverFile = path.join(builtLocalDirectory, "tsserver.js");
 compileFile(serverFile, serverSources,[builtLocalDirectory, copyright].concat(serverSources), /*prefixes*/ [copyright], /*useBuiltCompiler*/ true);
 
+var lsslFile = path.join(builtLocalDirectory, "tslssl.js");
+compileFile(
+    lsslFile, 
+    languageServiceLibrarySources, 
+    [builtLocalDirectory, copyright].concat(languageServiceLibrarySources),
+    /*prefixes*/ [copyright], 
+    /*useBuiltCompiler*/ true, 
+    /*noOutFile*/ false, 
+    /*generateDeclarations*/ true);
+
+// Local target to build the language service server library
+desc("Builds language service server library");
+task("lssl", [lsslFile]);
+
 // Local target to build the compiler and services
 desc("Builds the full compiler and services");
 task("local", ["generate-diagnostics", "lib", tscFile, servicesFile, nodeDefinitionsFile, serverFile]);
diff --git a/bin/tsc.js b/bin/tsc.js
index c55b3be37ba..16408e9c208 100644
--- a/bin/tsc.js
+++ b/bin/tsc.js
@@ -24740,7 +24740,7 @@ var ts;
                         emitDeclarationName(node);
                         write("\", ");
                         emitDeclarationName(node);
-                        write(")");
+                        write(");");
                     }
                     emitExportMemberAssignments(node.name);
                 }
@@ -24848,7 +24848,7 @@ var ts;
                         emitDeclarationName(node);
                         write("\", ");
                         emitDeclarationName(node);
-                        write(")");
+                        write(");");
                     }
                     emitExportMemberAssignments(node.name);
                 }
diff --git a/bin/tsserver.js b/bin/tsserver.js
index 71ff883dbce..9c655a0b0c1 100644
--- a/bin/tsserver.js
+++ b/bin/tsserver.js
@@ -25131,7 +25131,7 @@ var ts;
                         emitDeclarationName(node);
                         write("\", ");
                         emitDeclarationName(node);
-                        write(")");
+                        write(");");
                     }
                     emitExportMemberAssignments(node.name);
                 }
@@ -25239,7 +25239,7 @@ var ts;
                         emitDeclarationName(node);
                         write("\", ");
                         emitDeclarationName(node);
-                        write(")");
+                        write(");");
                     }
                     emitExportMemberAssignments(node.name);
                 }
diff --git a/bin/typescript.js b/bin/typescript.js
index 3dd6dd919be..138a38642c9 100644
--- a/bin/typescript.js
+++ b/bin/typescript.js
@@ -29466,7 +29466,7 @@ var ts;
                         emitDeclarationName(node);
                         write("\", ");
                         emitDeclarationName(node);
-                        write(")");
+                        write(");");
                     }
                     emitExportMemberAssignments(node.name);
                 }
@@ -29576,7 +29576,7 @@ var ts;
                         emitDeclarationName(node);
                         write("\", ");
                         emitDeclarationName(node);
-                        write(")");
+                        write(");");
                     }
                     emitExportMemberAssignments(node.name);
                 }
diff --git a/bin/typescriptServices.js b/bin/typescriptServices.js
index 3dd6dd919be..138a38642c9 100644
--- a/bin/typescriptServices.js
+++ b/bin/typescriptServices.js
@@ -29466,7 +29466,7 @@ var ts;
                         emitDeclarationName(node);
                         write("\", ");
                         emitDeclarationName(node);
-                        write(")");
+                        write(");");
                     }
                     emitExportMemberAssignments(node.name);
                 }
@@ -29576,7 +29576,7 @@ var ts;
                         emitDeclarationName(node);
                         write("\", ");
                         emitDeclarationName(node);
-                        write(")");
+                        write(");");
                     }
                     emitExportMemberAssignments(node.name);
                 }
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 741863f0334..3b9b0301fb8 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -159,6 +159,14 @@ namespace ts {
             }
         };
 
+        let subtypeRelation: Map<RelationComparisonResult> = {};
+        let assignableRelation: Map<RelationComparisonResult> = {};
+        let identityRelation: Map<RelationComparisonResult> = {};
+
+        initializeTypeChecker();
+
+        return checker;
+
         function getEmitResolver(sourceFile?: SourceFile) {
             // Ensure we have all the type information in place for this file so that all the
             // emitter questions of this resolver will return the right information.
@@ -357,21 +365,38 @@ namespace ts {
                     case SyntaxKind.SourceFile:
                         if (!isExternalModule(<SourceFile>location)) break;
                     case SyntaxKind.ModuleDeclaration:
-                        if (result = getSymbol(getSymbolOfNode(location).exports, name, meaning & SymbolFlags.ModuleMember)) {
-                            if (result.flags & meaning || !(result.flags & SymbolFlags.Alias && getDeclarationOfAliasSymbol(result).kind === SyntaxKind.ExportSpecifier)) {
-                                break loop;
-                            }
-                            result = undefined;
-                        }
-                        else if (location.kind === SyntaxKind.SourceFile ||
+                        let moduleExports = getSymbolOfNode(location).exports;
+                        if (location.kind === SyntaxKind.SourceFile ||
                             (location.kind === SyntaxKind.ModuleDeclaration && (<ModuleDeclaration>location).name.kind === SyntaxKind.StringLiteral)) {
-                            result = getSymbolOfNode(location).exports["default"];
+                            
+                            // It's an external module. Because of module/namespace merging, a module's exports are in scope,
+                            // yet we never want to treat an export specifier as putting a member in scope. Therefore,
+                            // if the name we find is purely an export specifier, it is not actually considered in scope.
+                            // Two things to note about this:
+                            //     1. We have to check this without calling getSymbol. The problem with calling getSymbol
+                            //        on an export specifier is that it might find the export specifier itself, and try to
+                            //        resolve it as an alias. This will cause the checker to consider the export specifier
+                            //        a circular alias reference when it might not be.
+                            //     2. We check === SymbolFlags.Alias in order to check that the symbol is *purely*
+                            //        an alias. If we used &, we'd be throwing out symbols that have non alias aspects,
+                            //        which is not the desired behavior.
+                            if (hasProperty(moduleExports, name) &&
+                                moduleExports[name].flags === SymbolFlags.Alias &&
+                                getDeclarationOfKind(moduleExports[name], SyntaxKind.ExportSpecifier)) {
+                                break;
+                            }
+
+                            result = moduleExports["default"];
                             let localSymbol = getLocalSymbolForExportDefault(result);
                             if (result && localSymbol && (result.flags & meaning) && localSymbol.name === name) {
                                 break loop;
                             }
                             result = undefined;
                         }
+
+                        if (result = getSymbol(moduleExports, name, meaning & SymbolFlags.ModuleMember)) {
+                            break loop;
+                        }
                         break;
                     case SyntaxKind.EnumDeclaration:
                         if (result = getSymbol(getSymbolOfNode(location).exports, name, meaning & SymbolFlags.EnumMember)) {
@@ -2639,7 +2664,8 @@ namespace ts {
                 }
                 let baseConstructorType = checkExpression(baseTypeNode.expression);
                 if (baseConstructorType.flags & TypeFlags.ObjectType) {
-                    // Force resolution of members such that we catch circularities
+                    // Resolving the members of a class requires us to resolve the base class of that class.
+                    // We force resolution here such that we catch circularities now.
                     resolveObjectOrUnionTypeMembers(baseConstructorType);
                 }
                 if (!popTypeResolution()) {
@@ -2647,7 +2673,7 @@ namespace ts {
                     return type.resolvedBaseConstructorType = unknownType;
                 }
                 if (baseConstructorType !== unknownType && baseConstructorType !== nullType && !isConstructorType(baseConstructorType)) {
-                    error(baseTypeNode.expression, Diagnostics.Base_expression_is_not_of_a_constructor_function_type);
+                    error(baseTypeNode.expression, Diagnostics.Type_0_is_not_a_constructor_function_type, typeToString(baseConstructorType));
                     return type.resolvedBaseConstructorType = unknownType;
                 }
                 type.resolvedBaseConstructorType = baseConstructorType;
@@ -2699,7 +2725,7 @@ namespace ts {
                 return;
             }
             if (!(getTargetType(baseType).flags & (TypeFlags.Class | TypeFlags.Interface))) {
-                error(baseTypeNode.expression, Diagnostics.Base_constructor_does_not_return_a_class_or_interface_type);
+                error(baseTypeNode.expression, Diagnostics.Base_constructor_return_type_0_is_not_a_class_or_interface_type, typeToString(baseType));
                 return;
             }
             if (type === baseType || hasBaseType(<InterfaceType>baseType, type)) {
@@ -3599,7 +3625,7 @@ namespace ts {
                             // -> typeParameter and symbol.declaration originate from the same type parameter list
                             // -> illegal for all declarations in symbol
                             // forEach === exists
-                            links.isIllegalTypeReferenceInConstraint = forEach(symbol.declarations, d => d.parent == typeParameter.parent);
+                            links.isIllegalTypeReferenceInConstraint = forEach(symbol.declarations, d => d.parent === typeParameter.parent);
                         }
                     }
                     if (links.isIllegalTypeReferenceInConstraint) {
@@ -4220,10 +4246,6 @@ namespace ts {
 
         // TYPE CHECKING
 
-        let subtypeRelation: Map<RelationComparisonResult> = {};
-        let assignableRelation: Map<RelationComparisonResult> = {};
-        let identityRelation: Map<RelationComparisonResult> = {};
-
         function isTypeIdenticalTo(source: Type, target: Type): boolean {
             return checkTypeRelatedTo(source, target, identityRelation, /*errorNode*/ undefined);
         }
@@ -5777,6 +5799,7 @@ namespace ts {
                 let signature = getResolvedSignature(expr);
 
                 if (signature.typePredicate &&
+                    expr.arguments[signature.typePredicate.parameterIndex] &&
                     getSymbolAtLocation(expr.arguments[signature.typePredicate.parameterIndex]) === symbol) {
 
                     if (!assumeTrue) {
@@ -5979,7 +6002,9 @@ namespace ts {
             let baseClassType = classType && getBaseTypes(classType)[0];
 
             if (!baseClassType) {
-                error(node, Diagnostics.super_can_only_be_referenced_in_a_derived_class);
+                if (!classDeclaration || !getClassExtendsHeritageClauseElement(classDeclaration)) {
+                    error(node, Diagnostics.super_can_only_be_referenced_in_a_derived_class);
+                }
                 return unknownType;
             }
 
@@ -8548,7 +8573,7 @@ namespace ts {
         // contextually typed function and arrow expressions in the initial phase.
         function checkExpression(node: Expression | QualifiedName, contextualMapper?: TypeMapper): Type {
             let type: Type;
-            if (node.kind == SyntaxKind.QualifiedName) {
+            if (node.kind === SyntaxKind.QualifiedName) {
                 type = checkQualifiedName(<QualifiedName>node);
             }
             else {
@@ -9032,15 +9057,16 @@ namespace ts {
             checkDecorators(node);
         }
 
-        function checkTypeArgumentsAndConstraints(typeParameters: TypeParameter[], typeArguments: TypeNode[]) {
-            for (let i = 0; i < typeArguments.length; i++) {
-                let typeArgument = typeArguments[i];
-                checkSourceElement(typeArgument);
+        function checkTypeArgumentConstraints(typeParameters: TypeParameter[], typeArguments: TypeNode[]): boolean {
+            let result = true;
+            for (let i = 0; i < typeParameters.length; i++) {
                 let constraint = getConstraintOfTypeParameter(typeParameters[i]);
-                if (produceDiagnostics && constraint) {
-                    checkTypeAssignableTo(getTypeFromTypeNode(typeArgument), constraint, typeArgument, Diagnostics.Type_0_does_not_satisfy_the_constraint_1);
+                if (constraint) {
+                    let typeArgument = typeArguments[i];
+                    result = result && checkTypeAssignableTo(getTypeFromTypeNode(typeArgument), constraint, typeArgument, Diagnostics.Type_0_does_not_satisfy_the_constraint_1);
                 }
             }
+            return result;
         }
 
         function checkTypeReferenceNode(node: TypeReferenceNode | ExpressionWithTypeArguments) {
@@ -9048,9 +9074,12 @@ namespace ts {
             let type = getTypeFromTypeReference(node);
             if (type !== unknownType && node.typeArguments) {
                 // Do type argument local checks only if referenced type is successfully resolved
-                let symbol = getNodeLinks(node).resolvedSymbol;
-                let typeParameters = symbol.flags & SymbolFlags.TypeAlias ? getSymbolLinks(symbol).typeParameters : (<TypeReference>type).target.localTypeParameters;
-                checkTypeArgumentsAndConstraints(typeParameters, node.typeArguments);
+                forEach(node.typeArguments, checkSourceElement);
+                if (produceDiagnostics) {
+                    let symbol = getNodeLinks(node).resolvedSymbol;
+                    let typeParameters = symbol.flags & SymbolFlags.TypeAlias ? getSymbolLinks(symbol).typeParameters : (<TypeReference>type).target.localTypeParameters;
+                    checkTypeArgumentConstraints(typeParameters, node.typeArguments);
+                }
             }
         }
 
@@ -9995,7 +10024,7 @@ namespace ts {
         function checkForStatement(node: ForStatement) {
             // Grammar checking
             if (!checkGrammarStatementInAmbientContext(node)) {
-                if (node.initializer && node.initializer.kind == SyntaxKind.VariableDeclarationList) {
+                if (node.initializer && node.initializer.kind === SyntaxKind.VariableDeclarationList) {
                     checkGrammarVariableDeclarationList(<VariableDeclarationList>node.initializer);
                 }
             }
@@ -10665,8 +10694,12 @@ namespace ts {
                     let baseType = baseTypes[0];
                     let staticBaseType = getBaseConstructorTypeOfClass(type);
                     if (baseTypeNode.typeArguments) {
-                        let constructors = getConstructorsForTypeArguments(staticBaseType, baseTypeNode.typeArguments);
-                        checkTypeArgumentsAndConstraints(constructors[0].typeParameters, baseTypeNode.typeArguments);
+                        forEach(baseTypeNode.typeArguments, checkSourceElement);
+                        for (let constructor of getConstructorsForTypeArguments(staticBaseType, baseTypeNode.typeArguments)) {
+                            if (!checkTypeArgumentConstraints(constructor.typeParameters, baseTypeNode.typeArguments)) {
+                                break;
+                            }
+                        }
                     }
                     checkTypeAssignableTo(type, baseType, node.name || node, Diagnostics.Class_0_incorrectly_extends_base_class_1);
                     checkTypeAssignableTo(staticType, getTypeWithoutSignatures(staticBaseType), node.name || node,
@@ -10676,7 +10709,9 @@ namespace ts {
 
                     if (!(staticBaseType.symbol && staticBaseType.symbol.flags & SymbolFlags.Class)) {
                         // When the static base type is a "class-like" constructor function (but not actually a class), we verify
-                        // that all instantiated base constructor signatures return the same type.
+                        // that all instantiated base constructor signatures return the same type. We can simply compare the type
+                        // references (as opposed to checking the structure of the types) because elsewhere we have already checked
+                        // that the base type is a class or interface type (and not, for example, an anonymous object type).
                         let constructors = getInstantiatedConstructorsForTypeArguments(staticBaseType, baseTypeNode.typeArguments);
                         if (forEach(constructors, sig => getReturnTypeOfSignature(sig) !== baseType)) {
                             error(baseTypeNode.expression, Diagnostics.Base_constructors_must_all_have_the_same_return_type);
@@ -11888,7 +11923,7 @@ namespace ts {
         }
 
         function isTypeDeclarationName(name: Node): boolean {
-            return name.kind == SyntaxKind.Identifier &&
+            return name.kind === SyntaxKind.Identifier &&
                 isTypeDeclaration(name.parent) &&
                 (<Declaration>name.parent).name === name;
         }
@@ -12057,7 +12092,7 @@ namespace ts {
 
                 case SyntaxKind.NumericLiteral:
                     // index access
-                    if (node.parent.kind == SyntaxKind.ElementAccessExpression && (<ElementAccessExpression>node.parent).argumentExpression === node) {
+                    if (node.parent.kind === SyntaxKind.ElementAccessExpression && (<ElementAccessExpression>node.parent).argumentExpression === node) {
                         let objectType = checkExpression((<ElementAccessExpression>node.parent).expression);
                         if (objectType === unknownType) return undefined;
                         let apparentType = getApparentType(objectType);
@@ -12093,7 +12128,7 @@ namespace ts {
                 return getTypeOfExpression(<Expression>node);
             }
 
-            if (isClassExtendsExpressionWithTypeArguments(node)) {
+            if (isExpressionWithTypeArgumentsInClassExtendsClause(node)) {
                 // A SyntaxKind.ExpressionWithTypeArguments is considered a type node, except when it occurs in the
                 // extends clause of a class. We handle that case here.
                 return getBaseTypes(<InterfaceType>getDeclaredTypeOfSymbol(getSymbolOfNode(node.parent.parent)))[0];
@@ -13730,9 +13765,5 @@ namespace ts {
                 return true;
             }
         }
-
-        initializeTypeChecker();
-
-        return checker;
     }
 }
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 0c0414f3b12..ced477eeeec 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -572,7 +572,7 @@ namespace ts {
     export function getNormalizedPathComponents(path: string, currentDirectory: string) {
         path = normalizeSlashes(path);
         let rootLength = getRootLength(path);
-        if (rootLength == 0) {
+        if (rootLength === 0) {
             // If the path is not rooted it is relative to current directory
             path = combinePaths(normalizeSlashes(currentDirectory), path);
             rootLength = getRootLength(path);
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 649e9b69a76..fe35e7aced6 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -712,7 +712,12 @@ namespace ts {
         function writeModuleDeclaration(node: ModuleDeclaration) {
             emitJsDocComments(node);
             emitModuleElementDeclarationFlags(node);
-            write("module ");
+            if (node.flags & NodeFlags.Namespace) {
+                write("namespace ");
+            }
+            else {
+                write("module ");
+            }
             writeTextOfNode(currentSourceFile, node.name);
             while (node.body.kind !== SyntaxKind.ModuleBlock) {
                 node = <ModuleDeclaration>node.body;
diff --git a/src/compiler/diagnosticInformationMap.generated.ts b/src/compiler/diagnosticInformationMap.generated.ts
index 071570482df..343b4e22738 100644
--- a/src/compiler/diagnosticInformationMap.generated.ts
+++ b/src/compiler/diagnosticInformationMap.generated.ts
@@ -389,9 +389,9 @@ namespace ts {
         No_best_common_type_exists_among_yield_expressions: { code: 2504, category: DiagnosticCategory.Error, key: "No best common type exists among yield expressions." },
         A_generator_cannot_have_a_void_type_annotation: { code: 2505, category: DiagnosticCategory.Error, key: "A generator cannot have a 'void' type annotation." },
         _0_is_referenced_directly_or_indirectly_in_its_own_base_expression: { code: 2506, category: DiagnosticCategory.Error, key: "'{0}' is referenced directly or indirectly in its own base expression." },
-        Base_expression_is_not_of_a_constructor_function_type: { code: 2507, category: DiagnosticCategory.Error, key: "Base expression is not of a constructor function type." },
+        Type_0_is_not_a_constructor_function_type: { code: 2507, category: DiagnosticCategory.Error, key: "Type '{0}' is not a constructor function type." },
         No_base_constructor_has_the_specified_number_of_type_arguments: { code: 2508, category: DiagnosticCategory.Error, key: "No base constructor has the specified number of type arguments." },
-        Base_constructor_does_not_return_a_class_or_interface_type: { code: 2509, category: DiagnosticCategory.Error, key: "Base constructor does not return a class or interface type." },
+        Base_constructor_return_type_0_is_not_a_class_or_interface_type: { code: 2509, category: DiagnosticCategory.Error, key: "Base constructor return type '{0}' is not a class or interface type." },
         Base_constructors_must_all_have_the_same_return_type: { code: 2510, category: DiagnosticCategory.Error, key: "Base constructors must all have the same return type." },
         Cannot_create_an_instance_of_the_abstract_class_0: { code: 2511, category: DiagnosticCategory.Error, key: "Cannot create an instance of the abstract class '{0}'." },
         All_overload_signatures_must_match_with_respect_to_modifier_0: { code: 2512, category: DiagnosticCategory.Error, key: "All overload signatures must match with respect to modifier '{0}'." },
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 85c8e46c246..b14d885dd9a 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1543,7 +1543,7 @@
         "category": "Error",
         "code": 2506
     },
-    "Base expression is not of a constructor function type.": {
+    "Type '{0}' is not a constructor function type.": {
         "category": "Error",
         "code": 2507
     },
@@ -1551,7 +1551,7 @@
         "category": "Error",
         "code": 2508
     },
-    "Base constructor does not return a class or interface type.": {
+    "Base constructor return type '{0}' is not a class or interface type.": {
         "category": "Error",
         "code": 2509
     },
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 8081668f98c..3fbe640254f 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -21,8 +21,7 @@ namespace ts {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };`;
 
         // emit output for the __decorate helper function
@@ -320,7 +319,7 @@ var __param = (this && this.__param) || function (paramIndex, decorator) {
 
                     let prevEncodedEmittedColumn = lastEncodedSourceMapSpan.emittedColumn;
                     // Line/Comma delimiters
-                    if (lastEncodedSourceMapSpan.emittedLine == lastRecordedSourceMapSpan.emittedLine) {
+                    if (lastEncodedSourceMapSpan.emittedLine === lastRecordedSourceMapSpan.emittedLine) {
                         // Emit comma to separate the entry
                         if (sourceMapData.sourceMapMappings) {
                             sourceMapData.sourceMapMappings += ",";
@@ -403,8 +402,8 @@ var __param = (this && this.__param) || function (paramIndex, decorator) {
 
                     // If this location wasn't recorded or the location in source is going backwards, record the span
                     if (!lastRecordedSourceMapSpan ||
-                        lastRecordedSourceMapSpan.emittedLine != emittedLine ||
-                        lastRecordedSourceMapSpan.emittedColumn != emittedColumn ||
+                        lastRecordedSourceMapSpan.emittedLine !== emittedLine ||
+                        lastRecordedSourceMapSpan.emittedColumn !== emittedColumn ||
                         (lastRecordedSourceMapSpan.sourceIndex === sourceMapSourceIndex &&
                             (lastRecordedSourceMapSpan.sourceLine > sourceLinePos.line ||
                                 (lastRecordedSourceMapSpan.sourceLine === sourceLinePos.line && lastRecordedSourceMapSpan.sourceColumn > sourceLinePos.character)))) {
@@ -654,7 +653,7 @@ var __param = (this && this.__param) || function (paramIndex, decorator) {
                         if (nodeIsSynthesized(node)) {
                             return emitNodeWithoutSourceMap(node);
                         }
-                        if (node.kind != SyntaxKind.SourceFile) {
+                        if (node.kind !== SyntaxKind.SourceFile) {
                             recordEmitNodeStartSpan(node);
                             emitNodeWithoutSourceMap(node);
                             recordEmitNodeEndSpan(node);
@@ -1962,7 +1961,7 @@ var __param = (this && this.__param) || function (paramIndex, decorator) {
 
                         // Make sure we consider all nested cast expressions, e.g.:
                         // (<any><number><any>-A).x;
-                        while (operand.kind == SyntaxKind.TypeAssertionExpression) {
+                        while (operand.kind === SyntaxKind.TypeAssertionExpression) {
                             operand = (<TypeAssertion>operand).expression;
                         }
 
@@ -5348,7 +5347,7 @@ var __param = (this && this.__param) || function (paramIndex, decorator) {
                 decreaseIndent();
                 writeLine();
                 write("}"); // return
-                emitTempDeclarations(/*newLine*/ true)
+                emitTempDeclarations(/*newLine*/ true);
             }
 
             function emitSetters(exportStarFunction: string) {
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 886b73f3044..1b4426cefeb 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -1491,12 +1491,20 @@ namespace ts {
                 switch (node.kind) {
                     case SyntaxKind.Constructor:
                     case SyntaxKind.IndexSignature:
-                    case SyntaxKind.MethodDeclaration:
                     case SyntaxKind.GetAccessor:
                     case SyntaxKind.SetAccessor:
                     case SyntaxKind.PropertyDeclaration:
                     case SyntaxKind.SemicolonClassElement:
                         return true;
+                    case SyntaxKind.MethodDeclaration:
+                        // Method declarations are not necessarily reusable.  An object-literal
+                        // may have a method calls "constructor(...)" and we must reparse that
+                        // into an actual .ConstructorDeclaration.
+                        let methodDeclaration = <MethodDeclaration>node;
+                        let nameIsConstructor = methodDeclaration.name.kind === SyntaxKind.Identifier &&
+                            (<Identifier>methodDeclaration.name).originalKeywordKind === SyntaxKind.ConstructorKeyword;
+
+                        return !nameIsConstructor;
                 }
             }
 
@@ -3990,7 +3998,7 @@ namespace ts {
                         parseExportAssignment(fullStart, decorators, modifiers) :
                         parseExportDeclaration(fullStart, decorators, modifiers);
                 default:
-                    if (decorators) {
+                    if (decorators || modifiers) {
                         // We reached this point because we encountered decorators and/or modifiers and assumed a declaration
                         // would follow. For recovery and error reporting purposes, return an incomplete declaration.                        
                         let node = <Statement>createMissingNode(SyntaxKind.MissingDeclaration, /*reportAtCurrentPosition*/ true, Diagnostics.Declaration_expected);
@@ -4392,7 +4400,7 @@ namespace ts {
                 return parsePropertyOrMethodDeclaration(fullStart, decorators, modifiers);
             }
 
-            if (decorators) {
+            if (decorators || modifiers) {
                 // treat this as a property declaration with a missing name.
                 let name = <Identifier>createMissingNode(SyntaxKind.Identifier, /*reportAtCurrentPosition*/ true, Diagnostics.Declaration_expected);
                 return parsePropertyDeclaration(fullStart, decorators, modifiers, name, /*questionToken*/ undefined);
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 562654c2ed0..2af9ad9987d 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -105,7 +105,10 @@ namespace ts {
     }
 
     export function getPreEmitDiagnostics(program: Program, sourceFile?: SourceFile): Diagnostic[] {
-        let diagnostics = program.getSyntacticDiagnostics(sourceFile).concat(program.getGlobalDiagnostics()).concat(program.getSemanticDiagnostics(sourceFile));
+        let diagnostics = program.getOptionsDiagnostics().concat(
+                          program.getSyntacticDiagnostics(sourceFile),
+                          program.getGlobalDiagnostics(),
+                          program.getSemanticDiagnostics(sourceFile));
 
         if (program.getCompilerOptions().declaration) {
             diagnostics.concat(program.getDeclarationDiagnostics(sourceFile));
@@ -144,7 +147,7 @@ namespace ts {
         let program: Program;
         let files: SourceFile[] = [];
         let diagnostics = createDiagnosticCollection();
-
+
         let commonSourceDirectory: string;
         let diagnosticsProducingTypeChecker: TypeChecker;
         let noDiagnosticsTypeChecker: TypeChecker;
@@ -177,10 +180,10 @@ namespace ts {
             getSourceFiles: () => files,
             getCompilerOptions: () => options,
             getSyntacticDiagnostics,
+            getOptionsDiagnostics,
             getGlobalDiagnostics,
             getSemanticDiagnostics,
             getDeclarationDiagnostics,
-            getCompilerOptionsDiagnostics,
             getTypeChecker,
             getClassifiableNames,
             getDiagnosticsProducingTypeChecker,
@@ -311,19 +314,15 @@ namespace ts {
             }
         }
 
-        function getCompilerOptionsDiagnostics(): Diagnostic[] {
+        function getOptionsDiagnostics(): Diagnostic[] {
             let allDiagnostics: Diagnostic[] = [];
             addRange(allDiagnostics, diagnostics.getGlobalDiagnostics());
             return sortAndDeduplicateDiagnostics(allDiagnostics);
         }
 
         function getGlobalDiagnostics(): Diagnostic[] {
-            let typeChecker = getDiagnosticsProducingTypeChecker();
-
             let allDiagnostics: Diagnostic[] = [];
-            addRange(allDiagnostics, typeChecker.getGlobalDiagnostics());
-            addRange(allDiagnostics, diagnostics.getGlobalDiagnostics());
-
+            addRange(allDiagnostics, getDiagnosticsProducingTypeChecker().getGlobalDiagnostics());
             return sortAndDeduplicateDiagnostics(allDiagnostics);
         }
 
@@ -678,4 +677,4 @@ namespace ts {
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/compiler/scanner.ts b/src/compiler/scanner.ts
index 15f51775e0b..eb6c7f021fc 100644
--- a/src/compiler/scanner.ts
+++ b/src/compiler/scanner.ts
@@ -377,8 +377,31 @@ namespace ts {
         return ch >= CharacterCodes._0 && ch <= CharacterCodes._7;
     }
 
+    export function couldStartTrivia(text: string, pos: number): boolean {
+        // Keep in sync with skipTrivia
+        let ch = text.charCodeAt(pos);
+        switch (ch) {
+            case CharacterCodes.carriageReturn:
+            case CharacterCodes.lineFeed:
+            case CharacterCodes.tab:
+            case CharacterCodes.verticalTab:
+            case CharacterCodes.formFeed:
+            case CharacterCodes.space:
+            case CharacterCodes.slash:
+                // starts of normal trivia
+            case CharacterCodes.lessThan:
+            case CharacterCodes.equals:
+            case CharacterCodes.greaterThan:
+                // Starts of conflict marker trivia
+                return true;
+            default:
+                return ch > CharacterCodes.maxAsciiCharacter;
+        }
+    }
+
     /* @internal */ 
     export function skipTrivia(text: string, pos: number, stopAfterLineBreak?: boolean): number {
+        // Keep in sync with couldStartTrivia
         while (true) {
             let ch = text.charCodeAt(pos);
             switch (ch) {
@@ -935,7 +958,7 @@ namespace ts {
                 error(Diagnostics.Unexpected_end_of_text);
                 isInvalidExtendedEscape = true;
             }
-            else if (text.charCodeAt(pos) == CharacterCodes.closeBrace) {
+            else if (text.charCodeAt(pos) === CharacterCodes.closeBrace) {
                 // Only swallow the following character up if it's a '}'.
                 pos++;
             }
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 4c58f12b0ea..4575f172e29 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -1214,11 +1214,11 @@ namespace ts {
          */
         emit(targetSourceFile?: SourceFile, writeFile?: WriteFileCallback): EmitResult;
 
-        getSyntacticDiagnostics(sourceFile?: SourceFile): Diagnostic[];
+        getOptionsDiagnostics(): Diagnostic[];
         getGlobalDiagnostics(): Diagnostic[];
+        getSyntacticDiagnostics(sourceFile?: SourceFile): Diagnostic[];
         getSemanticDiagnostics(sourceFile?: SourceFile): Diagnostic[];
         getDeclarationDiagnostics(sourceFile?: SourceFile): Diagnostic[];
-        /* @internal */ getCompilerOptionsDiagnostics(): Diagnostic[];
 
         /** 
          * Gets a type checker that can be used to semantically analyze source fils in the program.
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 86000b9f6ea..dab5318c42d 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -42,7 +42,7 @@ namespace ts {
     // Pool writers to avoid needing to allocate them for every symbol we write.
     let stringWriters: StringSymbolWriter[] = [];
     export function getSingleLineStringWriter(): StringSymbolWriter {
-        if (stringWriters.length == 0) {
+        if (stringWriters.length === 0) {
             let str = "";
 
             let writeText: (text: string) => void = text => str += text;
@@ -426,7 +426,7 @@ namespace ts {
                 // Specialized signatures can have string literals as their parameters' type names
                 return node.parent.kind === SyntaxKind.Parameter;
             case SyntaxKind.ExpressionWithTypeArguments:
-                return !isClassExtendsExpressionWithTypeArguments(node);
+                return !isExpressionWithTypeArgumentsInClassExtendsClause(node);
 
             // Identifiers and qualified names may be type nodes, depending on their context. Climb
             // above them to find the lowest container
@@ -460,7 +460,7 @@ namespace ts {
                 }
                 switch (parent.kind) {
                     case SyntaxKind.ExpressionWithTypeArguments:
-                        return !isClassExtendsExpressionWithTypeArguments(parent);
+                        return !isExpressionWithTypeArgumentsInClassExtendsClause(parent);
                     case SyntaxKind.TypeParameter:
                         return node === (<TypeParameterDeclaration>parent).constraint;
                     case SyntaxKind.PropertyDeclaration:
@@ -920,7 +920,7 @@ namespace ts {
                     case SyntaxKind.Decorator:
                         return true;
                     case SyntaxKind.ExpressionWithTypeArguments:
-                        return isClassExtendsExpressionWithTypeArguments(parent);
+                        return (<ExpressionWithTypeArguments>parent).expression === node && isExpressionWithTypeArgumentsInClassExtendsClause(parent);
                     default:
                         if (isExpression(parent)) {
                             return true;
@@ -1916,7 +1916,7 @@ namespace ts {
         return token >= SyntaxKind.FirstAssignment && token <= SyntaxKind.LastAssignment;
     }
 
-    export function isClassExtendsExpressionWithTypeArguments(node: Node): boolean {
+    export function isExpressionWithTypeArgumentsInClassExtendsClause(node: Node): boolean {
         return node.kind === SyntaxKind.ExpressionWithTypeArguments &&
             (<HeritageClause>node.parent).token === SyntaxKind.ExtendsKeyword &&
             node.parent.parent.kind === SyntaxKind.ClassDeclaration;
@@ -2092,6 +2092,12 @@ namespace ts {
         return start <= textSpanEnd(span) && end >= span.start;
     }
 
+    export function decodedTextSpanIntersectsWith(start1: number, length1: number, start2: number, length2: number) {
+        let end1 = start1 + length1;
+        let end2 = start2 + length2;
+        return start2 <= end1 && end2 >= start1;
+    }
+
     export function textSpanIntersectsWithPosition(span: TextSpan, position: number) {
         return position <= textSpanEnd(span) && position >= span.start;
     }
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index bf6e120ec3c..5915698462c 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -831,6 +831,7 @@ module FourSlash {
                 if (expectedText !== undefined) {
                     assert.notEqual(actualQuickInfoText, expectedText, this.messageAtLastKnownMarker("quick info text"));
                 }
+                // TODO: should be '==='?
                 if (expectedDocumentation != undefined) {
                     assert.notEqual(actualQuickInfoDocumentation, expectedDocumentation, this.messageAtLastKnownMarker("quick info doc comment"));
                 }
@@ -838,6 +839,7 @@ module FourSlash {
                 if (expectedText !== undefined) {
                     assert.equal(actualQuickInfoText, expectedText, this.messageAtLastKnownMarker("quick info text"));
                 }
+                // TODO: should be '==='?
                 if (expectedDocumentation != undefined) {
                     assert.equal(actualQuickInfoDocumentation, expectedDocumentation, assertionMessage("quick info doc"));
                 }
@@ -1820,7 +1822,7 @@ module FourSlash {
         }
 
         private verifyProjectInfo(expected: string[]) {
-            if (this.testType == FourSlashTestType.Server) {
+            if (this.testType === FourSlashTestType.Server) {
                 let actual = (<ts.server.SessionClient>this.languageService).getProjectInfo(
                     this.activeFile.fileName,
                     /* needFileNameList */ true
@@ -1937,7 +1939,7 @@ module FourSlash {
                 }
             }
 
-            if (expected != actual) {
+            if (expected !== actual) {
                 this.raiseError('verifyNavigationItemsCount failed - found: ' + actual + ' navigation items, expected: ' + expected + '.');
             }
         }
@@ -1984,7 +1986,7 @@ module FourSlash {
             var items = this.languageService.getNavigationBarItems(this.activeFile.fileName);
             var actual = this.getNavigationBarItemsCount(items);
 
-            if (expected != actual) {
+            if (expected !== actual) {
                 this.raiseError('verifyGetScriptLexicalStructureListCount failed - found: ' + actual + ' navigation items, expected: ' + expected + '.');
             }
         }
@@ -2402,6 +2404,7 @@ module FourSlash {
                         globalOptions[match[1]] = match[2];
                     }
                 }
+            // TODO: should be '==='?
             } else if (line == '' || lineLength === 0) {
                 // Previously blank lines between fourslash content caused it to be considered as 2 files,
                 // Remove this behavior since it just causes errors now
diff --git a/src/harness/harnessLanguageService.ts b/src/harness/harnessLanguageService.ts
index 0e0b8d82918..8eb77817533 100644
--- a/src/harness/harnessLanguageService.ts
+++ b/src/harness/harnessLanguageService.ts
@@ -583,7 +583,7 @@ module Harness.LanguageService {
             // This host is just a proxy for the clientHost, it uses the client
             // host to answer server queries about files on disk
             var serverHost = new SessionServerHost(clientHost);
-            var server = new ts.server.Session(serverHost, serverHost);
+            var server = new ts.server.Session(serverHost, Buffer.byteLength, process.hrtime, serverHost);
 
             // Fake the connection between the client and the server
             serverHost.writeMessage = client.onMessage.bind(client);
diff --git a/src/harness/projectsRunner.ts b/src/harness/projectsRunner.ts
index 324524272e0..5eb0016ff8d 100644
--- a/src/harness/projectsRunner.ts
+++ b/src/harness/projectsRunner.ts
@@ -110,6 +110,7 @@ class ProjectRunner extends RunnerBase {
                 else if (url.indexOf(diskProjectPath) === 0) {
                     // Replace the disk specific path into the project root path
                     url = url.substr(diskProjectPath.length);
+                    // TODO: should be '!=='?
                     if (url.charCodeAt(0) != ts.CharacterCodes.slash) {
                         url = "/" + url;
                     }
@@ -240,7 +241,7 @@ class ProjectRunner extends RunnerBase {
                 if (Harness.Compiler.isJS(fileName)) {
                     // Make sure if there is URl we have it cleaned up
                     var indexOfSourceMapUrl = data.lastIndexOf("//# sourceMappingURL=");
-                    if (indexOfSourceMapUrl != -1) {
+                    if (indexOfSourceMapUrl !== -1) {
                         data = data.substring(0, indexOfSourceMapUrl + 21) + cleanProjectUrl(data.substring(indexOfSourceMapUrl + 21));
                     }
                 }
diff --git a/src/harness/runner.ts b/src/harness/runner.ts
index 42c2d5667c4..1e9c6470421 100644
--- a/src/harness/runner.ts
+++ b/src/harness/runner.ts
@@ -49,7 +49,6 @@ if (testConfigFile !== '') {
             if (!option) {
                 continue;
             }
-            ts.sys.write("Option: " + option + "\r\n");
             switch (option) {
                 case 'compiler':
                     runners.push(new CompilerBaselineRunner(CompilerTestType.Conformance));
diff --git a/src/harness/sourceMapRecorder.ts b/src/harness/sourceMapRecorder.ts
index 528e6ddd52b..ed079774d94 100644
--- a/src/harness/sourceMapRecorder.ts
+++ b/src/harness/sourceMapRecorder.ts
@@ -46,7 +46,7 @@ module Harness.SourceMapRecoder {
         }
 
         function isSourceMappingSegmentEnd() {
-            if (decodingIndex == sourceMapMappings.length) {
+            if (decodingIndex === sourceMapMappings.length) {
                 return true;
             }
 
@@ -95,7 +95,7 @@ module Harness.SourceMapRecoder {
                     var currentByte = base64FormatDecode();
 
                     // If msb is set, we still have more bits to continue
-                    moreDigits = (currentByte & 32) != 0;
+                    moreDigits = (currentByte & 32) !== 0;
 
                     // least significant 5 bits are the next msbs in the final value.
                     value = value | ((currentByte & 31) << shiftCount);
@@ -103,7 +103,7 @@ module Harness.SourceMapRecoder {
                 }
 
                 // Least significant bit if 1 represents negative and rest of the msb is actual absolute value
-                if ((value & 1) == 0) {
+                if ((value & 1) === 0) {
                     // + number
                     value = value >> 1;
                 }
@@ -182,7 +182,7 @@ module Harness.SourceMapRecoder {
                     }
                 }
                 // Dont support reading mappings that dont have information about original source and its line numbers
-                if (createErrorIfCondition(!isSourceMappingSegmentEnd(), "Unsupported Error Format: There are more entries after " + (decodeOfEncodedMapping.nameIndex == -1 ? "sourceColumn" : "nameIndex"))) {
+                if (createErrorIfCondition(!isSourceMappingSegmentEnd(), "Unsupported Error Format: There are more entries after " + (decodeOfEncodedMapping.nameIndex === -1 ? "sourceColumn" : "nameIndex"))) {
                     return { error: errorDecodeOfEncodedMapping, sourceMapSpan: decodeOfEncodedMapping };
                 }
 
@@ -249,7 +249,7 @@ module Harness.SourceMapRecoder {
                 mapString += " name (" + sourceMapNames[mapEntry.nameIndex] + ")";
             }
             else {
-                if (mapEntry.nameIndex != -1 || getAbsentNameIndex) {
+                if (mapEntry.nameIndex !== -1 || getAbsentNameIndex) {
                     mapString += " nameIndex (" + mapEntry.nameIndex + ")";
                 }
             }
@@ -262,12 +262,12 @@ module Harness.SourceMapRecoder {
             var decodeResult = SourceMapDecoder.decodeNextEncodedSourceMapSpan();
             var decodedErrors: string[];
             if (decodeResult.error
-                || decodeResult.sourceMapSpan.emittedLine != sourceMapSpan.emittedLine
-                || decodeResult.sourceMapSpan.emittedColumn != sourceMapSpan.emittedColumn
-                || decodeResult.sourceMapSpan.sourceLine != sourceMapSpan.sourceLine
-                || decodeResult.sourceMapSpan.sourceColumn != sourceMapSpan.sourceColumn
-                || decodeResult.sourceMapSpan.sourceIndex != sourceMapSpan.sourceIndex
-                || decodeResult.sourceMapSpan.nameIndex != sourceMapSpan.nameIndex) {
+                || decodeResult.sourceMapSpan.emittedLine   !== sourceMapSpan.emittedLine
+                || decodeResult.sourceMapSpan.emittedColumn !== sourceMapSpan.emittedColumn
+                || decodeResult.sourceMapSpan.sourceLine    !== sourceMapSpan.sourceLine
+                || decodeResult.sourceMapSpan.sourceColumn  !== sourceMapSpan.sourceColumn
+                || decodeResult.sourceMapSpan.sourceIndex   !== sourceMapSpan.sourceIndex
+                || decodeResult.sourceMapSpan.nameIndex     !== sourceMapSpan.nameIndex) {
                 if (decodeResult.error) {
                     decodedErrors = ["!!^^ !!^^ There was decoding error in the sourcemap at this location: " + decodeResult.error];
                 }
@@ -288,7 +288,7 @@ module Harness.SourceMapRecoder {
         }
 
         export function recordNewSourceFileSpan(sourceMapSpan: ts.SourceMapSpan, newSourceFileCode: string) {
-            assert.isTrue(spansOnSingleLine.length == 0 || spansOnSingleLine[0].sourceMapSpan.emittedLine !== sourceMapSpan.emittedLine, "new file source map span should be on new line. We currently handle only that scenario");
+            assert.isTrue(spansOnSingleLine.length === 0 || spansOnSingleLine[0].sourceMapSpan.emittedLine !== sourceMapSpan.emittedLine, "new file source map span should be on new line. We currently handle only that scenario");
             recordSourceMapSpan(sourceMapSpan);
 
             assert.isTrue(spansOnSingleLine.length === 1);
@@ -395,9 +395,9 @@ module Harness.SourceMapRecoder {
 
                 var tsCodeLineMap = ts.computeLineStarts(sourceText);
                 for (var i = 0; i < tsCodeLineMap.length; i++) {
-                    writeSourceMapIndent(prevEmittedCol, i == 0 ? markerIds[index] : "  >");
+                    writeSourceMapIndent(prevEmittedCol, i === 0 ? markerIds[index] : "  >");
                     sourceMapRecoder.Write(getTextOfLine(i, tsCodeLineMap, sourceText));
-                    if (i == tsCodeLineMap.length - 1) {
+                    if (i === tsCodeLineMap.length - 1) {
                         sourceMapRecoder.WriteLine("");
                     }
                 }
@@ -447,7 +447,7 @@ module Harness.SourceMapRecoder {
             for (var j = 0; j < sourceMapData.sourceMapDecodedMappings.length; j++) {
                 var decodedSourceMapping = sourceMapData.sourceMapDecodedMappings[j];
                 var currentSourceFile = program.getSourceFile(sourceMapData.inputSourceFileNames[decodedSourceMapping.sourceIndex]);
-                if (currentSourceFile != prevSourceFile) {
+                if (currentSourceFile !== prevSourceFile) {
                     SourceMapSpanWriter.recordNewSourceFileSpan(decodedSourceMapping, currentSourceFile.text);
                     prevSourceFile = currentSourceFile;
                 }
diff --git a/src/harness/typeWriter.ts b/src/harness/typeWriter.ts
index ac695fc23a4..b68e606c79d 100644
--- a/src/harness/typeWriter.ts
+++ b/src/harness/typeWriter.ts
@@ -43,7 +43,7 @@ class TypeWriterWalker {
 
         // Workaround to ensure we output 'C' instead of 'typeof C' for base class expressions
         // var type = this.checker.getTypeAtLocation(node);
-        var type = node.parent && ts.isClassExtendsExpressionWithTypeArguments(node.parent) && this.checker.getTypeAtLocation(node.parent) || this.checker.getTypeAtLocation(node);
+        var type = node.parent && ts.isExpressionWithTypeArgumentsInClassExtendsClause(node.parent) && this.checker.getTypeAtLocation(node.parent) || this.checker.getTypeAtLocation(node);
 
         ts.Debug.assert(type !== undefined, "type doesn't exist");
         var symbol = this.checker.getSymbolAtLocation(node);
diff --git a/src/lib/intl.d.ts b/src/lib/intl.d.ts
index 66e51ddbc5a..57df70672d4 100644
--- a/src/lib/intl.d.ts
+++ b/src/lib/intl.d.ts
@@ -41,6 +41,11 @@ declare module Intl {
         currency?: string;
         currencyDisplay?: string;
         useGrouping?: boolean;
+        minimumintegerDigits?: number;
+        minimumFractionDigits?: number;
+        maximumFractionDigits?: number;
+        minimumSignificantDigits?: number;
+        maximumSignificantDigits?: number;
     }
 
     interface ResolvedNumberFormatOptions {
@@ -103,7 +108,7 @@ declare module Intl {
     }
 
     interface DateTimeFormat {
-        format(date: number): string;
+        format(date?: Date | number): string;
         resolvedOptions(): ResolvedDateTimeFormatOptions;
     }
     var DateTimeFormat: {
diff --git a/src/server/client.ts b/src/server/client.ts
index 3546f8339ee..e4a524dd210 100644
--- a/src/server/client.ts
+++ b/src/server/client.ts
@@ -219,7 +219,7 @@ namespace ts.server {
 
             var request = this.processRequest<protocol.CompletionDetailsRequest>(CommandNames.CompletionDetails, args);
             var response = this.processResponse<protocol.CompletionDetailsResponse>(request);
-            Debug.assert(response.body.length == 1, "Unexpected length of completion details response body.");
+            Debug.assert(response.body.length === 1, "Unexpected length of completion details response body.");
             return response.body[0];
         }
 
@@ -429,8 +429,8 @@ namespace ts.server {
             if (!this.lastRenameEntry ||
                 this.lastRenameEntry.fileName !== fileName ||
                 this.lastRenameEntry.position !== position ||
-                this.lastRenameEntry.findInStrings != findInStrings ||
-                this.lastRenameEntry.findInComments != findInComments) {
+                this.lastRenameEntry.findInStrings !== findInStrings ||
+                this.lastRenameEntry.findInComments !== findInComments) {
                 this.getRenameInfo(fileName, position, findInStrings, findInComments);
             }
 
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 9e235e2cc7d..91d400ff263 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -2,7 +2,6 @@
 /// <reference path="..\services\services.ts" />
 /// <reference path="protocol.d.ts" />
 /// <reference path="session.ts" />
-/// <reference path="node.d.ts" />
 
 namespace ts.server {
     export interface Logger {
@@ -28,7 +27,7 @@ namespace ts.server {
         });
     }
 
-    class ScriptInfo {
+    export class ScriptInfo {
         svc: ScriptVersionCache;
         children: ScriptInfo[] = [];     // files referenced by this file
         defaultProject: Project;      // project to use by default for file
@@ -36,7 +35,7 @@ namespace ts.server {
         formatCodeOptions = ts.clone(CompilerService.defaultFormatCodeOptions);
 
         constructor(private host: ServerHost, public fileName: string, public content: string, public isOpen = false) {
-            this.svc = ScriptVersionCache.fromString(content);
+            this.svc = ScriptVersionCache.fromString(host, content);
         }
 
         setFormatOptions(formatOptions: protocol.FormatOptions): void {
@@ -80,7 +79,7 @@ namespace ts.server {
         }
     }
 
-    class LSHost implements ts.LanguageServiceHost {
+    export class LSHost implements ts.LanguageServiceHost {
         ls: ts.LanguageService = null;
         compilationSettings: ts.CompilerOptions;
         filenameToScript: ts.Map<ScriptInfo> = {};
@@ -273,7 +272,7 @@ namespace ts.server {
         }
     }
 
-    interface ProjectOptions {
+    export interface ProjectOptions {
         // these fields can be present in the project file
         files?: string[];
         compilerOptions?: ts.CompilerOptions;
@@ -376,7 +375,7 @@ namespace ts.server {
         }
     }
 
-    interface ProjectOpenResult {
+    export interface ProjectOpenResult {
         success?: boolean;
         errorMsg?: string;
         project?: Project;
@@ -392,11 +391,11 @@ namespace ts.server {
         return copiedList;
     }
 
-    interface ProjectServiceEventHandler {
+    export interface ProjectServiceEventHandler {
         (eventName: string, project: Project, fileName: string): void;
     }
 
-    interface HostConfiguration {
+    export interface HostConfiguration {
         formatCodeOptions: ts.FormatCodeOptions;
         hostInfo: string;
     }
@@ -629,7 +628,7 @@ namespace ts.server {
                 for (var i = 0, len = this.openFilesReferenced.length; i < len; i++) {
                     var f = this.openFilesReferenced[i];
                     // if f was referenced by the removed project, remember it
-                    if (f.defaultProject == removedProject) {
+                    if (f.defaultProject === removedProject) {
                         f.defaultProject = undefined;
                         orphanFiles.push(f);
                     }
@@ -656,7 +655,7 @@ namespace ts.server {
             for (var i = 0, len = this.inferredProjects.length; i < len; i++) {
                 var inferredProject = this.inferredProjects[i];
                 inferredProject.updateGraph();
-                if (inferredProject != excludedProject) {
+                if (inferredProject !== excludedProject) {
                     if (inferredProject.getSourceFile(info)) {
                         info.defaultProject = inferredProject;
                         referencingProjects.push(inferredProject);
@@ -710,7 +709,7 @@ namespace ts.server {
                 var rootFile = this.openFileRoots[i];
                 var rootedProject = rootFile.defaultProject;
                 var referencingProjects = this.findReferencingProjects(rootFile, rootedProject);
-                if (referencingProjects.length == 0) {
+                if (referencingProjects.length === 0) {
                     rootFile.defaultProject = rootedProject;
                     openFileRoots.push(rootFile);
                 }
@@ -916,7 +915,7 @@ namespace ts.server {
                 return rawConfig.error;
             }
             else {
-                var parsedCommandLine = ts.parseConfigFile(rawConfig.config, ts.sys, dirPath);
+                var parsedCommandLine = ts.parseConfigFile(rawConfig.config, this.host, dirPath);
                 if (parsedCommandLine.errors && (parsedCommandLine.errors.length > 0)) {
                     return { errorMsg: "tsconfig option errors" };
                 }
@@ -953,7 +952,7 @@ namespace ts.server {
 
     }
 
-    class CompilerService {
+    export class CompilerService {
         host: LSHost;
         languageService: ts.LanguageService;
         classifier: ts.Classifier;
@@ -985,7 +984,7 @@ namespace ts.server {
         static defaultFormatCodeOptions: ts.FormatCodeOptions = {
             IndentSize: 4,
             TabSize: 4,
-            NewLineCharacter: ts.sys.newLine,
+            NewLineCharacter: ts.sys ? ts.sys.newLine : '\n',
             ConvertTabsToSpaces: true,
             InsertSpaceAfterCommaDelimiter: true,
             InsertSpaceAfterSemicolonInForStatements: true,
@@ -999,7 +998,7 @@ namespace ts.server {
 
     }
 
-    interface LineCollection {
+    export interface LineCollection {
         charCount(): number;
         lineCount(): number;
         isLeaf(): boolean;
@@ -1013,7 +1012,7 @@ namespace ts.server {
         leaf?: LineLeaf;
     }
 
-    enum CharRangeSection {
+    export enum CharRangeSection {
         PreStart,
         Start,
         Entire,
@@ -1022,7 +1021,7 @@ namespace ts.server {
         PostEnd
     }
 
-    interface ILineIndexWalker {
+    export interface ILineIndexWalker {
         goSubtree: boolean;
         done: boolean;
         leaf(relativeStart: number, relativeLength: number, lineCollection: LineLeaf): void;
@@ -1082,7 +1081,7 @@ namespace ts.server {
 
             for (var k = this.endBranch.length - 1; k >= 0; k--) {
                 (<LineNode>this.endBranch[k]).updateCounts();
-                if (this.endBranch[k].charCount() == 0) {
+                if (this.endBranch[k].charCount() === 0) {
                     lastZeroCount = this.endBranch[k];
                     if (k > 0) {
                         branchParent = <LineNode>this.endBranch[k - 1];
@@ -1147,7 +1146,7 @@ namespace ts.server {
         post(relativeStart: number, relativeLength: number, lineCollection: LineCollection, parent: LineCollection, nodeType: CharRangeSection): LineCollection {
             // have visited the path for start of range, now looking for end
             // if range is on single line, we will never make this state transition
-            if (lineCollection == this.lineCollectionAtBranch) {
+            if (lineCollection === this.lineCollectionAtBranch) {
                 this.state = CharRangeSection.End;
             }
             // always pop stack because post only called when child has been visited
@@ -1159,7 +1158,7 @@ namespace ts.server {
             // currentNode corresponds to parent, but in the new tree
             var currentNode = this.stack[this.stack.length - 1];
 
-            if ((this.state == CharRangeSection.Entire) && (nodeType == CharRangeSection.Start)) {
+            if ((this.state === CharRangeSection.Entire) && (nodeType === CharRangeSection.Start)) {
                 // if range is on single line, we will never make this state transition
                 this.state = CharRangeSection.Start;
                 this.branchNode = currentNode;
@@ -1176,12 +1175,12 @@ namespace ts.server {
             switch (nodeType) {
                 case CharRangeSection.PreStart:
                     this.goSubtree = false;
-                    if (this.state != CharRangeSection.End) {
+                    if (this.state !== CharRangeSection.End) {
                         currentNode.add(lineCollection);
                     }
                     break;
                 case CharRangeSection.Start:
-                    if (this.state == CharRangeSection.End) {
+                    if (this.state === CharRangeSection.End) {
                         this.goSubtree = false;
                     }
                     else {
@@ -1191,7 +1190,7 @@ namespace ts.server {
                     }
                     break;
                 case CharRangeSection.Entire:
-                    if (this.state != CharRangeSection.End) {
+                    if (this.state !== CharRangeSection.End) {
                         child = fresh(lineCollection);
                         currentNode.add(child);
                         this.startPath[this.startPath.length] = child;
@@ -1208,7 +1207,7 @@ namespace ts.server {
                     this.goSubtree = false;
                     break;
                 case CharRangeSection.End:
-                    if (this.state != CharRangeSection.End) {
+                    if (this.state !== CharRangeSection.End) {
                         this.goSubtree = false;
                     }
                     else {
@@ -1221,7 +1220,7 @@ namespace ts.server {
                     break;
                 case CharRangeSection.PostEnd:
                     this.goSubtree = false;
-                    if (this.state != CharRangeSection.Start) {
+                    if (this.state !== CharRangeSection.Start) {
                         currentNode.add(lineCollection);
                     }
                     break;
@@ -1233,10 +1232,10 @@ namespace ts.server {
         }
         // just gather text from the leaves
         leaf(relativeStart: number, relativeLength: number, ll: LineLeaf) {
-            if (this.state == CharRangeSection.Start) {
+            if (this.state === CharRangeSection.Start) {
                 this.initialText = ll.text.substring(0, relativeStart);
             }
-            else if (this.state == CharRangeSection.Entire) {
+            else if (this.state === CharRangeSection.Entire) {
                 this.initialText = ll.text.substring(0, relativeStart);
                 this.trailingText = ll.text.substring(relativeStart + relativeLength);
             }
@@ -1248,7 +1247,7 @@ namespace ts.server {
     }
 
     // text change information
-    class TextChange {
+    export class TextChange {
         constructor(public pos: number, public deleteLen: number, public insertedText?: string) {
         }
 
@@ -1263,6 +1262,7 @@ namespace ts.server {
         versions: LineIndexSnapshot[] = [];
         minVersion = 0;  // no versions earlier than min version will maintain change history
         private currentVersion = 0;
+        private host: ServerHost;
 
         static changeNumberThreshold = 8;
         static changeLengthThreshold = 256;
@@ -1290,7 +1290,7 @@ namespace ts.server {
         }
 
         reloadFromFile(filename: string, cb?: () => any) {
-            var content = ts.sys.readFile(filename);
+            var content = this.host.readFile(filename);
             this.reload(content);
             if (cb)
                 cb();
@@ -1360,10 +1360,11 @@ namespace ts.server {
             }
         }
 
-        static fromString(script: string) {
+        static fromString(host: ServerHost, script: string) {
             var svc = new ScriptVersionCache();
             var snap = new LineIndexSnapshot(0, svc);
             svc.versions[svc.currentVersion] = snap;
+            svc.host = host;
             snap.index = new LineIndex();
             var lm = LineIndex.linesFromText(script);
             snap.index.load(lm.lines);
@@ -1371,7 +1372,7 @@ namespace ts.server {
         }
     }
 
-    class LineIndexSnapshot implements ts.IScriptSnapshot {
+    export class LineIndexSnapshot implements ts.IScriptSnapshot {
         index: LineIndex;
         changesSincePreviousVersion: TextChange[] = [];
 
@@ -1499,8 +1500,8 @@ namespace ts.server {
             function editFlat(source: string, s: number, dl: number, nt = "") {
                 return source.substring(0, s) + nt + source.substring(s + dl, source.length);
             }
-            if (this.root.charCount() == 0) {
-                // TODO: assert deleteLength == 0
+            if (this.root.charCount() === 0) {
+                // TODO: assert deleteLength === 0
                 if (newText) {
                     this.load(LineIndex.linesFromText(newText).lines);
                     return this;
@@ -1528,7 +1529,7 @@ namespace ts.server {
                     // check whether last characters deleted are line break
                     var e = pos + deleteLength;
                     var lineInfo = this.charOffsetToLineNumberAndPos(e);
-                    if ((lineInfo && (lineInfo.offset == 0))) {
+                    if ((lineInfo && (lineInfo.offset === 0))) {
                         // move range end just past line that will merge with previous line
                         deleteLength += lineInfo.text.length;
                         // store text by appending to end of insertedText
@@ -1574,7 +1575,7 @@ namespace ts.server {
                 interiorNodes[i].totalChars = charCount;
                 interiorNodes[i].totalLines = lineCount;
             }
-            if (interiorNodes.length == 1) {
+            if (interiorNodes.length === 1) {
                 return interiorNodes[0];
             }
             else {
@@ -1585,7 +1586,7 @@ namespace ts.server {
         static linesFromText(text: string) {
             var lineStarts = ts.computeLineStarts(text);
 
-            if (lineStarts.length == 0) {
+            if (lineStarts.length === 0) {
                 return { lines: <string[]>[], lineMap: lineStarts };
             }
             var lines = <string[]>new Array(lineStarts.length);
@@ -1605,7 +1606,7 @@ namespace ts.server {
         }
     }
 
-    class LineNode implements LineCollection {
+    export class LineNode implements LineCollection {
         totalChars = 0;
         totalLines = 0;
         children: LineCollection[] = [];
@@ -1821,7 +1822,7 @@ namespace ts.server {
         findChildIndex(child: LineCollection) {
             var childIndex = 0;
             var clen = this.children.length;
-            while ((this.children[childIndex] != child) && (childIndex < clen)) childIndex++;
+            while ((this.children[childIndex] !== child) && (childIndex < clen)) childIndex++;
             return childIndex;
         }
 
@@ -1830,7 +1831,7 @@ namespace ts.server {
             var clen = this.children.length;
             var nodeCount = nodes.length;
             // if child is last and there is more room and only one node to place, place it
-            if ((clen < lineCollectionCapacity) && (childIndex == (clen - 1)) && (nodeCount == 1)) {
+            if ((clen < lineCollectionCapacity) && (childIndex === (clen - 1)) && (nodeCount === 1)) {
                 this.add(nodes[0]);
                 this.updateCounts();
                 return [];
@@ -1854,13 +1855,13 @@ namespace ts.server {
                     var splitNode = <LineNode>splitNodes[0];
                     while (nodeIndex < nodeCount) {
                         splitNode.add(nodes[nodeIndex++]);
-                        if (splitNode.children.length == lineCollectionCapacity) {
+                        if (splitNode.children.length === lineCollectionCapacity) {
                             splitNodeIndex++;
                             splitNode = <LineNode>splitNodes[splitNodeIndex];
                         }
                     }
                     for (i = splitNodes.length - 1; i >= 0; i--) {
-                        if (splitNodes[i].children.length == 0) {
+                        if (splitNodes[i].children.length === 0) {
                             splitNodes.length--;
                         }
                     }
@@ -1891,7 +1892,7 @@ namespace ts.server {
         }
     }
 
-    class LineLeaf implements LineCollection {
+    export class LineLeaf implements LineCollection {
         udata: any;
 
         constructor(public text: string) {
diff --git a/src/server/node.d.ts b/src/server/node.d.ts
index 2002f973a37..8f7237382e5 100644
--- a/src/server/node.d.ts
+++ b/src/server/node.d.ts
@@ -584,9 +584,9 @@ declare module NodeJS {
         export interface Response extends Message {
             request_seq: number;
             success: boolean;
-            /** Contains error message if success == false. */
+            /** Contains error message if success === false. */
             message?: string;
-            /** Contains message body if success == true. */
+            /** Contains message body if success === true. */
             body?: any;
         }
 
diff --git a/src/server/protocol.d.ts b/src/server/protocol.d.ts
index 336bc11c9f3..017a8c1d81a 100644
--- a/src/server/protocol.d.ts
+++ b/src/server/protocol.d.ts
@@ -67,12 +67,12 @@ declare namespace ts.server.protocol {
         command: string;
 
         /** 
-          * Contains error message if success == false. 
+          * Contains error message if success === false. 
           */
         message?: string;
 
         /**
-          * Contains message body if success == true.
+          * Contains message body if success === true.
           */
         body?: any;
     }
diff --git a/src/server/server.ts b/src/server/server.ts
index b4b35edd3f3..843197b918a 100644
--- a/src/server/server.ts
+++ b/src/server/server.ts
@@ -11,7 +11,7 @@ namespace ts.server {
         input: process.stdin,
         output: process.stdout,
         terminal: false,
-    });
+    });  
 
     class Logger implements ts.server.Logger {
         fd = -1;
@@ -123,7 +123,7 @@ namespace ts.server {
                 if (err) {
                     watchedFile.callback(watchedFile.fileName);
                 }
-                else if (watchedFile.mtime.getTime() != stats.mtime.getTime()) {
+                else if (watchedFile.mtime.getTime() !== stats.mtime.getTime()) {
                     watchedFile.mtime = WatchedFileSet.getModifiedTime(watchedFile.fileName);
                     watchedFile.callback(watchedFile.fileName);
                 }
@@ -138,7 +138,7 @@ namespace ts.server {
                 var count = 0;
                 var nextToCheck = this.nextFileToCheck;
                 var firstCheck = -1;
-                while ((count < this.chunkSize) && (nextToCheck != firstCheck)) {
+                while ((count < this.chunkSize) && (nextToCheck !== firstCheck)) {
                     this.poll(nextToCheck);
                     if (firstCheck < 0) {
                         firstCheck = nextToCheck;
@@ -170,11 +170,11 @@ namespace ts.server {
         removeFile(file: WatchedFile) {
             this.watchedFiles = WatchedFileSet.copyListRemovingItem(file, this.watchedFiles);
         }
-    }
+    } 
 
     class IOSession extends Session {
         constructor(host: ServerHost, logger: ts.server.Logger) {
-            super(host, logger);
+            super(host, Buffer.byteLength, process.hrtime, logger);
         }
 
         exit() {
diff --git a/src/server/session.ts b/src/server/session.ts
index f9cfb4f9f7d..c95b1a7cc1b 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -1,6 +1,5 @@
 /// <reference path="..\compiler\commandLineParser.ts" />
 /// <reference path="..\services\services.ts" />
-/// <reference path="node.d.ts" />
 /// <reference path="protocol.d.ts" />
 /// <reference path="editorServices.ts" />
 
@@ -31,7 +30,7 @@ namespace ts.server {
         if (a < b) {
             return -1;
         }
-        else if (a == b) {
+        else if (a === b) {
             return 0;
         }
         else return 1;
@@ -43,7 +42,7 @@ namespace ts.server {
         }
         else if (a.file == b.file) {
             var n = compareNumber(a.start.line, b.start.line);
-            if (n == 0) {
+            if (n === 0) {
                 return compareNumber(a.start.offset, b.start.offset);
             }
             else return n;
@@ -61,7 +60,7 @@ namespace ts.server {
         };
     }
 
-    interface PendingErrorCheck {
+    export interface PendingErrorCheck {
         fileName: string;
         project: Project;
     }
@@ -114,11 +113,16 @@ namespace ts.server {
         pendingOperation = false;
         fileHash: ts.Map<number> = {};
         nextFileId = 1;
-        errorTimer: NodeJS.Timer;
+        errorTimer: any; /*NodeJS.Timer | number*/
         immediateId: any;
         changeSeq = 0;
 
-        constructor(private host: ServerHost, private logger: Logger) {
+        constructor(
+            private host: ServerHost, 
+            private byteLength: (buf: string, encoding?: string) => number, 
+            private hrtime: (start?: number[]) => number[], 
+            private logger: Logger
+        ) {
             this.projectService =
                 new ProjectService(host, logger, (eventName,project,fileName) => {
                 this.handleEvent(eventName, project, fileName);
@@ -129,7 +133,7 @@ namespace ts.server {
             if (eventName == "context") {
                 this.projectService.log("got context event, updating diagnostics for" + fileName, "Info");
                 this.updateErrorCheck([{ fileName, project }], this.changeSeq,
-                    (n) => n == this.changeSeq, 100);
+                    (n) => n === this.changeSeq, 100);
             }
         }
 
@@ -149,17 +153,17 @@ namespace ts.server {
             this.host.write(line + this.host.newLine);
         }
 
-        send(msg: NodeJS._debugger.Message) {
+        send(msg: protocol.Message) {
             var json = JSON.stringify(msg);
             if (this.logger.isVerbose()) {
                 this.logger.info(msg.type + ": " + json);
             }
-            this.sendLineToClient('Content-Length: ' + (1 + Buffer.byteLength(json, 'utf8')) +
+            this.sendLineToClient('Content-Length: ' + (1 + this.byteLength(json, 'utf8')) +
                 '\r\n\r\n' + json);
         }
 
         event(info: any, eventName: string) {
-            var ev: NodeJS._debugger.Event = {
+            var ev: protocol.Event = {
                 seq: 0,
                 type: "event",
                 event: eventName,
@@ -546,7 +550,7 @@ namespace ts.server {
             // getFormattingEditsAfterKeytroke either empty or pertaining
             // only to the previous line.  If all this is true, then
             // add edits necessary to properly indent the current line.
-            if ((key == "\n") && ((!edits) || (edits.length == 0) || allEditsBeforePos(edits, position))) {
+            if ((key == "\n") && ((!edits) || (edits.length === 0) || allEditsBeforePos(edits, position))) {
                 var scriptInfo = compilerService.host.getScriptInfo(file);
                 if (scriptInfo) {
                     var lineInfo = scriptInfo.getLineInfo(line);
@@ -622,7 +626,7 @@ namespace ts.server {
             }
 
             return completions.entries.reduce((result: protocol.CompletionEntry[], entry: ts.CompletionEntry) => {
-                if (completions.isMemberCompletion || (entry.name.toLowerCase().indexOf(prefix.toLowerCase()) == 0)) {
+                if (completions.isMemberCompletion || (entry.name.toLowerCase().indexOf(prefix.toLowerCase()) === 0)) {
                     result.push(entry);
                 }
                 return result;
@@ -689,7 +693,7 @@ namespace ts.server {
             }, []);
 
             if (checkList.length > 0) {
-                this.updateErrorCheck(checkList, this.changeSeq,(n) => n == this.changeSeq, delay)
+                this.updateErrorCheck(checkList, this.changeSeq,(n) => n === this.changeSeq, delay)
             }
         }
 
@@ -704,7 +708,7 @@ namespace ts.server {
                     compilerService.host.editScript(file, start, end, insertString);
                     this.changeSeq++;
                 }
-                this.updateProjectStructure(this.changeSeq, (n) => n == this.changeSeq);
+                this.updateProjectStructure(this.changeSeq, (n) => n === this.changeSeq);
             }
         }
 
@@ -838,7 +842,7 @@ namespace ts.server {
         onMessage(message: string) {
             if (this.logger.isVerbose()) {
                 this.logger.info("request: " + message);
-                var start = process.hrtime();                
+                var start = this.hrtime();                
             }
             try {
                 var request = <protocol.Request>JSON.parse(message);
@@ -980,7 +984,7 @@ namespace ts.server {
                 }
 
                 if (this.logger.isVerbose()) {
-                    var elapsed = process.hrtime(start);
+                    var elapsed = this.hrtime(start);
                     var seconds = elapsed[0]
                     var nanoseconds = elapsed[1];
                     var elapsedMs = ((1e9 * seconds) + nanoseconds)/1000000.0;
diff --git a/src/services/breakpoints.ts b/src/services/breakpoints.ts
index 4d3d7d331a5..227ba6a7970 100644
--- a/src/services/breakpoints.ts
+++ b/src/services/breakpoints.ts
@@ -75,7 +75,7 @@ namespace ts.BreakpointResolver {
                         return textSpan(node);
                     }
 
-                    if (node.parent.kind == SyntaxKind.ArrowFunction && (<FunctionLikeDeclaration>node.parent).body == node) {
+                    if (node.parent.kind === SyntaxKind.ArrowFunction && (<FunctionLikeDeclaration>node.parent).body === node) {
                         // If this is body of arrow function, it is allowed to have the breakpoint
                         return textSpan(node);
                     }
diff --git a/src/services/formatting/formattingContext.ts b/src/services/formatting/formattingContext.ts
index c9b9952a49e..ab182797a3c 100644
--- a/src/services/formatting/formattingContext.ts
+++ b/src/services/formatting/formattingContext.ts
@@ -59,7 +59,7 @@ namespace ts.formatting {
             if (this.tokensAreOnSameLine === undefined) {
                 let startLine = this.sourceFile.getLineAndCharacterOfPosition(this.currentTokenSpan.pos).line;
                 let endLine = this.sourceFile.getLineAndCharacterOfPosition(this.nextTokenSpan.pos).line;
-                this.tokensAreOnSameLine = (startLine == endLine);
+                this.tokensAreOnSameLine = (startLine === endLine);
             }
 
             return this.tokensAreOnSameLine;
@@ -84,7 +84,7 @@ namespace ts.formatting {
         private NodeIsOnOneLine(node: Node): boolean {
             let startLine = this.sourceFile.getLineAndCharacterOfPosition(node.getStart(this.sourceFile)).line;
             let endLine = this.sourceFile.getLineAndCharacterOfPosition(node.getEnd()).line;
-            return startLine == endLine;
+            return startLine === endLine;
         }
 
         private BlockIsOnOneLine(node: Node): boolean {
diff --git a/src/services/formatting/ruleOperationContext.ts b/src/services/formatting/ruleOperationContext.ts
index 515250d7264..47330faa0dd 100644
--- a/src/services/formatting/ruleOperationContext.ts
+++ b/src/services/formatting/ruleOperationContext.ts
@@ -14,7 +14,7 @@ namespace ts.formatting {
 
 
         public IsAny(): boolean {
-            return this == RuleOperationContext.Any;
+            return this === RuleOperationContext.Any;
         }
 
         public  InContext(context: FormattingContext): boolean {
diff --git a/src/services/formatting/rules.ts b/src/services/formatting/rules.ts
index 3e150e61a81..0e5b1623a5a 100644
--- a/src/services/formatting/rules.ts
+++ b/src/services/formatting/rules.ts
@@ -692,7 +692,7 @@ namespace ts.formatting {
         }
 
         static IsNotFormatOnEnter(context: FormattingContext): boolean {
-            return context.formattingRequestKind != FormattingRequestKind.FormatOnEnter;
+            return context.formattingRequestKind !== FormattingRequestKind.FormatOnEnter;
         }
 
         static IsModuleDeclContext(context: FormattingContext): boolean {
diff --git a/src/services/formatting/rulesMap.ts b/src/services/formatting/rulesMap.ts
index 4f231bd842e..bffbb75c02e 100644
--- a/src/services/formatting/rulesMap.ts
+++ b/src/services/formatting/rulesMap.ts
@@ -41,15 +41,15 @@ namespace ts.formatting {
         }
 
         private FillRule(rule: Rule, rulesBucketConstructionStateList: RulesBucketConstructionState[]): void {
-            let specificRule = rule.Descriptor.LeftTokenRange != Shared.TokenRange.Any &&
-                               rule.Descriptor.RightTokenRange != Shared.TokenRange.Any;
+            let specificRule = rule.Descriptor.LeftTokenRange !== Shared.TokenRange.Any &&
+                               rule.Descriptor.RightTokenRange !== Shared.TokenRange.Any;
 
             rule.Descriptor.LeftTokenRange.GetTokens().forEach((left) => {
                 rule.Descriptor.RightTokenRange.GetTokens().forEach((right) => {
                     let rulesBucketIndex = this.GetRuleBucketIndex(left, right);
 
                     let rulesBucket = this.map[rulesBucketIndex];
-                    if (rulesBucket == undefined) {
+                    if (rulesBucket === undefined) {
                         rulesBucket = this.map[rulesBucketIndex] = new RulesBucket();
                     }
 
@@ -124,7 +124,7 @@ namespace ts.formatting {
         public IncreaseInsertionIndex(maskPosition: RulesPosition): void {
             let value = (this.rulesInsertionIndexBitmap >> maskPosition) & Mask;
             value++;
-            Debug.assert((value & Mask) == value, "Adding more rules into the sub-bucket than allowed. Maximum allowed is 32 rules.");
+            Debug.assert((value & Mask) === value, "Adding more rules into the sub-bucket than allowed. Maximum allowed is 32 rules.");
 
             let temp = this.rulesInsertionIndexBitmap & ~(Mask << maskPosition);
             temp |= value << maskPosition;
@@ -147,7 +147,7 @@ namespace ts.formatting {
         public AddRule(rule: Rule, specificTokens: boolean, constructionState: RulesBucketConstructionState[], rulesBucketIndex: number): void {
             let position: RulesPosition;
 
-            if (rule.Operation.Action == RuleAction.Ignore) {
+            if (rule.Operation.Action === RuleAction.Ignore) {
                 position = specificTokens ?
                     RulesPosition.IgnoreRulesSpecific :
                     RulesPosition.IgnoreRulesAny;
diff --git a/src/services/formatting/rulesProvider.ts b/src/services/formatting/rulesProvider.ts
index bd8f4fc3a5e..ac1494571d1 100644
--- a/src/services/formatting/rulesProvider.ts
+++ b/src/services/formatting/rulesProvider.ts
@@ -25,6 +25,7 @@ namespace ts.formatting {
         }
 
         public ensureUpToDate(options: ts.FormatCodeOptions) {
+            // TODO: Should this be '==='?
             if (this.options == null || !ts.compareDataObjects(this.options, options)) {
                 let activeRules = this.createActiveRules(options);
                 let rulesMap = RulesMap.create(activeRules);
diff --git a/src/services/formatting/tokenRange.ts b/src/services/formatting/tokenRange.ts
index 27a43280f2c..3391365f328 100644
--- a/src/services/formatting/tokenRange.ts
+++ b/src/services/formatting/tokenRange.ts
@@ -54,7 +54,7 @@ namespace ts.formatting {
             }
 
             public Contains(tokenValue: SyntaxKind): boolean {
-                return tokenValue == this.token;
+                return tokenValue === this.token;
             }
         }
 
diff --git a/src/services/patternMatcher.ts b/src/services/patternMatcher.ts
index d56c7fac975..ea433867c46 100644
--- a/src/services/patternMatcher.ts
+++ b/src/services/patternMatcher.ts
@@ -686,7 +686,7 @@ namespace ts {
 
             if (charIsPunctuation(identifier.charCodeAt(i - 1)) ||
                 charIsPunctuation(identifier.charCodeAt(i)) ||
-                lastIsDigit != currentIsDigit ||
+                lastIsDigit !== currentIsDigit ||
                 hasTransitionFromLowerToUpper ||
                 hasTransitionFromUpperToLower) {
 
@@ -757,7 +757,7 @@ namespace ts {
             // 3) HTMLDocument -> HTML, Document
             //
             // etc.
-            if (index != wordStart &&
+            if (index !== wordStart &&
                 index + 1 < identifier.length) {
                 let currentIsUpper = isUpperCaseLetter(identifier.charCodeAt(index));
                 let nextIsLower = isLowerCaseLetter(identifier.charCodeAt(index + 1));
diff --git a/src/services/services.ts b/src/services/services.ts
index a8411ff1554..ee720088bdb 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -167,7 +167,7 @@ namespace ts {
         }
 
         public getFullWidth(): number {
-            return this.end - this.getFullStart();
+            return this.end - this.pos;
         }
 
         public getLeadingTriviaWidth(sourceFile?: SourceFile): number {
@@ -973,6 +973,9 @@ namespace ts {
 
         getSyntacticDiagnostics(fileName: string): Diagnostic[];
         getSemanticDiagnostics(fileName: string): Diagnostic[];
+
+        // TODO: Rename this to getProgramDiagnostics to better indicate that these are any
+        // diagnostics present for the program level, and not just 'options' diagnostics.
         getCompilerOptionsDiagnostics(): Diagnostic[];
 
         /** 
@@ -1790,11 +1793,6 @@ namespace ts {
             sourceFile.moduleName = moduleName;
         }
 
-        // Store syntactic diagnostics
-        if (diagnostics && sourceFile.parseDiagnostics) {
-            diagnostics.push(...sourceFile.parseDiagnostics);
-        }
-
         let newLine = getNewLineCharacter(options);
 
         // Output
@@ -1816,9 +1814,8 @@ namespace ts {
 
         var program = createProgram([inputFileName], options, compilerHost);
 
-        if (diagnostics) {
-            diagnostics.push(...program.getCompilerOptionsDiagnostics());
-        }
+        addRange(/*to*/ diagnostics, /*from*/ program.getSyntacticDiagnostics(sourceFile));
+        addRange(/*to*/ diagnostics, /*from*/ program.getOptionsDiagnostics());
 
         // Emit
         program.emit();
@@ -2798,7 +2795,7 @@ namespace ts {
 
         function getCompilerOptionsDiagnostics() {
             synchronizeHostData();
-            return program.getGlobalDiagnostics();
+            return program.getOptionsDiagnostics().concat(program.getGlobalDiagnostics());
         }
 
         /// Completion
@@ -4190,7 +4187,7 @@ namespace ts {
                 var result: DefinitionInfo[] = [];
                 forEach((<UnionType>type).types, t => {
                     if (t.symbol) {
-                        result.push(...getDefinitionFromSymbol(t.symbol, node));
+                        addRange(/*to*/ result, /*from*/ getDefinitionFromSymbol(t.symbol, node));
                     }
                 });
                 return result;
@@ -5814,7 +5811,7 @@ namespace ts {
             }
 
             return node.parent.kind === SyntaxKind.TypeReference ||
-                (node.parent.kind === SyntaxKind.ExpressionWithTypeArguments && !isClassExtendsExpressionWithTypeArguments(<ExpressionWithTypeArguments>node.parent));
+                (node.parent.kind === SyntaxKind.ExpressionWithTypeArguments && !isExpressionWithTypeArgumentsInClassExtendsClause(<ExpressionWithTypeArguments>node.parent));
         }
 
         function isNamespaceReference(node: Node): boolean {
@@ -6046,7 +6043,8 @@ namespace ts {
                  */
                 function hasValueSideModule(symbol: Symbol): boolean {
                     return forEach(symbol.declarations, declaration => {
-                        return declaration.kind === SyntaxKind.ModuleDeclaration && getModuleInstanceState(declaration) == ModuleInstanceState.Instantiated;
+                        return declaration.kind === SyntaxKind.ModuleDeclaration && 
+                            getModuleInstanceState(declaration) === ModuleInstanceState.Instantiated;
                     });
                 }
             }
@@ -6119,6 +6117,8 @@ namespace ts {
         function getEncodedSyntacticClassifications(fileName: string, span: TextSpan): Classifications {
             // doesn't use compiler - no need to synchronize with host
             let sourceFile = syntaxTreeCache.getCurrentSourceFile(fileName);
+            let spanStart = span.start;
+            let spanLength = span.length;
 
             // Make a scanner we can get trivia from.
             let triviaScanner = createScanner(ScriptTarget.Latest, /*skipTrivia:*/ false, sourceFile.text);
@@ -6135,48 +6135,55 @@ namespace ts {
                 result.push(type);
             }
 
-            function classifyLeadingTrivia(token: Node): void {
-                let tokenStart = skipTrivia(sourceFile.text, token.pos, /*stopAfterLineBreak:*/ false);
-                if (tokenStart === token.pos) {
-                    return;
-                }
-
-                // token has trivia.  Classify them appropriately.
+            function classifyLeadingTriviaAndGetTokenStart(token: Node): number {
                 triviaScanner.setTextPos(token.pos);
                 while (true) {
                     let start = triviaScanner.getTextPos();
+                    // only bother scanning if we have something that could be trivia.
+                    if (!couldStartTrivia(sourceFile.text, start)) {
+                        return start;
+                    }
+
                     let kind = triviaScanner.scan();
                     let end = triviaScanner.getTextPos();
                     let width = end - start;
 
                     // The moment we get something that isn't trivia, then stop processing.
                     if (!isTrivia(kind)) {
-                        return;
+                        return start;
+                    }
+
+                    // Don't bother with newlines/whitespace.
+                    if (kind === SyntaxKind.NewLineTrivia || kind === SyntaxKind.WhitespaceTrivia) {
+                        continue;
                     }
 
                     // Only bother with the trivia if it at least intersects the span of interest.
-                    if (textSpanIntersectsWith(span, start, width)) {
-                        if (isComment(kind)) {
-                            classifyComment(token, kind, start, width);
+                    if (isComment(kind)) {
+                        classifyComment(token, kind, start, width);
+                            
+                        // Classifying a comment might cause us to reuse the trivia scanner 
+                        // (because of jsdoc comments).  So after we classify the comment make
+                        // sure we set the scanner position back to where it needs to be.
+                        triviaScanner.setTextPos(end);
+                        continue;
+                    }
+
+                    if (kind === SyntaxKind.ConflictMarkerTrivia) {
+                        let text = sourceFile.text;
+                        let ch = text.charCodeAt(start);
+
+                        // for the <<<<<<< and >>>>>>> markers, we just add them in as comments
+                        // in the classification stream.
+                        if (ch === CharacterCodes.lessThan || ch === CharacterCodes.greaterThan) {
+                            pushClassification(start, width, ClassificationType.comment);
                             continue;
                         }
 
-                        if (kind === SyntaxKind.ConflictMarkerTrivia) {
-                            let text = sourceFile.text;
-                            let ch = text.charCodeAt(start);
-
-                            // for the <<<<<<< and >>>>>>> markers, we just add them in as comments
-                            // in the classification stream.
-                            if (ch === CharacterCodes.lessThan || ch === CharacterCodes.greaterThan) {
-                                pushClassification(start, width, ClassificationType.comment);
-                                continue;
-                            }
-
-                            // for the ======== add a comment for the first line, and then lex all
-                            // subsequent lines up until the end of the conflict marker.
-                            Debug.assert(ch === CharacterCodes.equals);
-                            classifyDisabledMergeCode(text, start, end);
-                        }
+                        // for the ======== add a comment for the first line, and then lex all
+                        // subsequent lines up until the end of the conflict marker.
+                        Debug.assert(ch === CharacterCodes.equals);
+                        classifyDisabledMergeCode(text, start, end);
                     }
                 }
             }
@@ -6295,12 +6302,14 @@ namespace ts {
             }
 
             function classifyToken(token: Node): void {
-                classifyLeadingTrivia(token);
+                let tokenStart = classifyLeadingTriviaAndGetTokenStart(token);
 
-                if (token.getWidth() > 0) {
+                let tokenWidth = token.end - tokenStart;
+                Debug.assert(tokenWidth >= 0);
+                if (tokenWidth > 0) {
                     let type = classifyTokenType(token.kind, token);
                     if (type) {
-                        pushClassification(token.getStart(), token.getWidth(), type);
+                        pushClassification(tokenStart, tokenWidth, type);
                     }
                 }
             }
@@ -6405,9 +6414,10 @@ namespace ts {
                 }
 
                 // Ignore nodes that don't intersect the original span to classify.
-                if (textSpanIntersectsWith(span, element.getFullStart(), element.getFullWidth())) {
+                if (decodedTextSpanIntersectsWith(spanStart, spanLength, element.pos, element.getFullWidth())) {
                     let children = element.getChildren(sourceFile);
-                    for (let child of children) {
+                    for (let i = 0, n = children.length; i < n; i++) {
+                        let child = children[i];
                         if (isToken(child)) {
                             classifyToken(child);
                         }
diff --git a/src/services/shims.ts b/src/services/shims.ts
index 9a586a1ec12..2e8b3eb774d 100644
--- a/src/services/shims.ts
+++ b/src/services/shims.ts
@@ -234,6 +234,7 @@ namespace ts {
         public getChangeRange(oldSnapshot: IScriptSnapshot): TextChangeRange {
             var oldSnapshotShim = <ScriptSnapshotShimAdapter>oldSnapshot;
             var encoded = this.scriptSnapshotShim.getChangeRange(oldSnapshotShim.scriptSnapshotShim);
+            // TODO: should this be '==='?
             if (encoded == null) {
                 return null;
             }
@@ -283,6 +284,7 @@ namespace ts {
 
         public getCompilationSettings(): CompilerOptions {
             var settingsJson = this.shimHost.getCompilationSettings();
+            // TODO: should this be '==='?
             if (settingsJson == null || settingsJson == "") {
                 throw Error("LanguageServiceShimHostAdapter.getCompilationSettings: empty compilationSettings");
                 return null;
diff --git a/tests/baselines/reference/ExportClassWithAccessibleTypesInTypeParameterConstraintsClassHeritageListMemberTypeAnnotations.js b/tests/baselines/reference/ExportClassWithAccessibleTypesInTypeParameterConstraintsClassHeritageListMemberTypeAnnotations.js
index ec30d5b4dc7..3e48462062d 100644
--- a/tests/baselines/reference/ExportClassWithAccessibleTypesInTypeParameterConstraintsClassHeritageListMemberTypeAnnotations.js
+++ b/tests/baselines/reference/ExportClassWithAccessibleTypesInTypeParameterConstraintsClassHeritageListMemberTypeAnnotations.js
@@ -24,8 +24,7 @@ module A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A;
 (function (A) {
diff --git a/tests/baselines/reference/ExportClassWithInaccessibleTypeInTypeParameterConstraint.js b/tests/baselines/reference/ExportClassWithInaccessibleTypeInTypeParameterConstraint.js
index 4d296bf9ea5..a1386033e9f 100644
--- a/tests/baselines/reference/ExportClassWithInaccessibleTypeInTypeParameterConstraint.js
+++ b/tests/baselines/reference/ExportClassWithInaccessibleTypeInTypeParameterConstraint.js
@@ -28,8 +28,7 @@ module A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A;
 (function (A) {
diff --git a/tests/baselines/reference/accessOverriddenBaseClassMember1.js b/tests/baselines/reference/accessOverriddenBaseClassMember1.js
index f6d3f29f1ab..e3a4d0602b8 100644
--- a/tests/baselines/reference/accessOverriddenBaseClassMember1.js
+++ b/tests/baselines/reference/accessOverriddenBaseClassMember1.js
@@ -19,8 +19,7 @@ class ColoredPoint extends Point {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Point = (function () {
     function Point(x, y) {
diff --git a/tests/baselines/reference/accessors_spec_section-4.5_inference.js b/tests/baselines/reference/accessors_spec_section-4.5_inference.js
index 8b75e27031a..808019448b7 100644
--- a/tests/baselines/reference/accessors_spec_section-4.5_inference.js
+++ b/tests/baselines/reference/accessors_spec_section-4.5_inference.js
@@ -28,8 +28,7 @@ class LanguageSpec_section_4_5_inference {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/aliasUsageInAccessorsOfClass.js b/tests/baselines/reference/aliasUsageInAccessorsOfClass.js
index 06c8b55e23d..11e02297e47 100644
--- a/tests/baselines/reference/aliasUsageInAccessorsOfClass.js
+++ b/tests/baselines/reference/aliasUsageInAccessorsOfClass.js
@@ -38,8 +38,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsage1_backbone");
 var VisualizationModel = (function (_super) {
diff --git a/tests/baselines/reference/aliasUsageInArray.js b/tests/baselines/reference/aliasUsageInArray.js
index e5d44320c7d..ba0c954a3c2 100644
--- a/tests/baselines/reference/aliasUsageInArray.js
+++ b/tests/baselines/reference/aliasUsageInArray.js
@@ -32,8 +32,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInArray_backbone");
 var VisualizationModel = (function (_super) {
diff --git a/tests/baselines/reference/aliasUsageInFunctionExpression.js b/tests/baselines/reference/aliasUsageInFunctionExpression.js
index b7b95661ac8..702cbe4d53f 100644
--- a/tests/baselines/reference/aliasUsageInFunctionExpression.js
+++ b/tests/baselines/reference/aliasUsageInFunctionExpression.js
@@ -31,8 +31,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInFunctionExpression_backbone");
 var VisualizationModel = (function (_super) {
diff --git a/tests/baselines/reference/aliasUsageInGenericFunction.js b/tests/baselines/reference/aliasUsageInGenericFunction.js
index 856e6ddb43e..8706dd592eb 100644
--- a/tests/baselines/reference/aliasUsageInGenericFunction.js
+++ b/tests/baselines/reference/aliasUsageInGenericFunction.js
@@ -35,8 +35,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInGenericFunction_backbone");
 var VisualizationModel = (function (_super) {
diff --git a/tests/baselines/reference/aliasUsageInIndexerOfClass.js b/tests/baselines/reference/aliasUsageInIndexerOfClass.js
index e05f5e4f5cd..78ddd2d4a94 100644
--- a/tests/baselines/reference/aliasUsageInIndexerOfClass.js
+++ b/tests/baselines/reference/aliasUsageInIndexerOfClass.js
@@ -37,8 +37,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInIndexerOfClass_backbone");
 var VisualizationModel = (function (_super) {
diff --git a/tests/baselines/reference/aliasUsageInObjectLiteral.js b/tests/baselines/reference/aliasUsageInObjectLiteral.js
index cc4b8273e84..f38cdf2111c 100644
--- a/tests/baselines/reference/aliasUsageInObjectLiteral.js
+++ b/tests/baselines/reference/aliasUsageInObjectLiteral.js
@@ -32,8 +32,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInObjectLiteral_backbone");
 var VisualizationModel = (function (_super) {
diff --git a/tests/baselines/reference/aliasUsageInOrExpression.js b/tests/baselines/reference/aliasUsageInOrExpression.js
index f382ee2f617..906a2c019d7 100644
--- a/tests/baselines/reference/aliasUsageInOrExpression.js
+++ b/tests/baselines/reference/aliasUsageInOrExpression.js
@@ -35,8 +35,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInOrExpression_backbone");
 var VisualizationModel = (function (_super) {
diff --git a/tests/baselines/reference/aliasUsageInTypeArgumentOfExtendsClause.js b/tests/baselines/reference/aliasUsageInTypeArgumentOfExtendsClause.js
index 39ff58a5322..27f85bb5fcd 100644
--- a/tests/baselines/reference/aliasUsageInTypeArgumentOfExtendsClause.js
+++ b/tests/baselines/reference/aliasUsageInTypeArgumentOfExtendsClause.js
@@ -35,8 +35,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInTypeArgumentOfExtendsClause_backbone");
 var VisualizationModel = (function (_super) {
@@ -51,8 +50,7 @@ exports.VisualizationModel = VisualizationModel;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var moduleA = require("aliasUsageInTypeArgumentOfExtendsClause_moduleA");
 var C = (function () {
diff --git a/tests/baselines/reference/aliasUsageInVarAssignment.js b/tests/baselines/reference/aliasUsageInVarAssignment.js
index 2de34f00566..bfc63868ff4 100644
--- a/tests/baselines/reference/aliasUsageInVarAssignment.js
+++ b/tests/baselines/reference/aliasUsageInVarAssignment.js
@@ -31,8 +31,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInVarAssignment_backbone");
 var VisualizationModel = (function (_super) {
diff --git a/tests/baselines/reference/ambiguousOverloadResolution.js b/tests/baselines/reference/ambiguousOverloadResolution.js
index 8c2ceb055c7..23c985d2f8d 100644
--- a/tests/baselines/reference/ambiguousOverloadResolution.js
+++ b/tests/baselines/reference/ambiguousOverloadResolution.js
@@ -12,8 +12,7 @@ var t: number = f(x, x); // Not an error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/apparentTypeSubtyping.js b/tests/baselines/reference/apparentTypeSubtyping.js
index 087a91fb02c..edc0f21323a 100644
--- a/tests/baselines/reference/apparentTypeSubtyping.js
+++ b/tests/baselines/reference/apparentTypeSubtyping.js
@@ -27,8 +27,7 @@ class Derived2<U extends String> extends Base2 { // error because of the prototy
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/apparentTypeSupertype.js b/tests/baselines/reference/apparentTypeSupertype.js
index 0b4462bebe7..2ab84c89513 100644
--- a/tests/baselines/reference/apparentTypeSupertype.js
+++ b/tests/baselines/reference/apparentTypeSupertype.js
@@ -17,8 +17,7 @@ class Derived<U extends String> extends Base { // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/arrayAssignmentTest1.js b/tests/baselines/reference/arrayAssignmentTest1.js
index 43aad9921bb..70177b4cba2 100644
--- a/tests/baselines/reference/arrayAssignmentTest1.js
+++ b/tests/baselines/reference/arrayAssignmentTest1.js
@@ -89,8 +89,7 @@ arr_any = i1; // should be an error - is
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function () {
     function C1() {
diff --git a/tests/baselines/reference/arrayAssignmentTest2.js b/tests/baselines/reference/arrayAssignmentTest2.js
index 5aeb74114bc..61bddd7e8e4 100644
--- a/tests/baselines/reference/arrayAssignmentTest2.js
+++ b/tests/baselines/reference/arrayAssignmentTest2.js
@@ -63,8 +63,7 @@ arr_any = i1; // should be an error - is
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function () {
     function C1() {
diff --git a/tests/baselines/reference/arrayBestCommonTypes.js b/tests/baselines/reference/arrayBestCommonTypes.js
index 8d2445e2739..95dd299ad43 100644
--- a/tests/baselines/reference/arrayBestCommonTypes.js
+++ b/tests/baselines/reference/arrayBestCommonTypes.js
@@ -111,8 +111,7 @@ module NonEmptyTypes {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var EmptyTypes;
 (function (EmptyTypes) {
diff --git a/tests/baselines/reference/arrayLiteralTypeInference.js b/tests/baselines/reference/arrayLiteralTypeInference.js
index dfd662bbf1c..fc573aa390e 100644
--- a/tests/baselines/reference/arrayLiteralTypeInference.js
+++ b/tests/baselines/reference/arrayLiteralTypeInference.js
@@ -55,8 +55,7 @@ var z3: { id: number }[] =
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Action = (function () {
     function Action() {
diff --git a/tests/baselines/reference/arrayLiterals.js b/tests/baselines/reference/arrayLiterals.js
index cb1d25258f2..0f86b7a7f2a 100644
--- a/tests/baselines/reference/arrayLiterals.js
+++ b/tests/baselines/reference/arrayLiterals.js
@@ -41,8 +41,7 @@ var context4: Base[] = [new Derived1(), new Derived1()];
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var arr1 = [[], [1], ['']];
 var arr2 = [[null], [1], ['']];
diff --git a/tests/baselines/reference/arrayLiteralsWithRecursiveGenerics.js b/tests/baselines/reference/arrayLiteralsWithRecursiveGenerics.js
index b3c0a0f7877..e303415df08 100644
--- a/tests/baselines/reference/arrayLiteralsWithRecursiveGenerics.js
+++ b/tests/baselines/reference/arrayLiteralsWithRecursiveGenerics.js
@@ -29,8 +29,7 @@ var as = [list, myDerivedList]; // List<number>[]
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var List = (function () {
     function List() {
diff --git a/tests/baselines/reference/arrowFunctionContexts.js b/tests/baselines/reference/arrowFunctionContexts.js
index f4a11fb47ae..5d862dcec8c 100644
--- a/tests/baselines/reference/arrowFunctionContexts.js
+++ b/tests/baselines/reference/arrowFunctionContexts.js
@@ -100,8 +100,7 @@ var asserted2: any;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // Arrow function used in with statement
 with (window) {
diff --git a/tests/baselines/reference/assignmentCompatWithCallSignatures3.js b/tests/baselines/reference/assignmentCompatWithCallSignatures3.js
index 1ad82ca531b..6f2eaf4d5cc 100644
--- a/tests/baselines/reference/assignmentCompatWithCallSignatures3.js
+++ b/tests/baselines/reference/assignmentCompatWithCallSignatures3.js
@@ -104,8 +104,7 @@ b18 = a18; // ok
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/assignmentCompatWithCallSignatures4.js b/tests/baselines/reference/assignmentCompatWithCallSignatures4.js
index 387395525ad..fc6ca05ad30 100644
--- a/tests/baselines/reference/assignmentCompatWithCallSignatures4.js
+++ b/tests/baselines/reference/assignmentCompatWithCallSignatures4.js
@@ -103,8 +103,7 @@ module Errors {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Errors;
 (function (Errors) {
diff --git a/tests/baselines/reference/assignmentCompatWithCallSignatures5.js b/tests/baselines/reference/assignmentCompatWithCallSignatures5.js
index 2e3790cd529..ddf16c23f48 100644
--- a/tests/baselines/reference/assignmentCompatWithCallSignatures5.js
+++ b/tests/baselines/reference/assignmentCompatWithCallSignatures5.js
@@ -70,8 +70,7 @@ b18 = a18; // ok
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/assignmentCompatWithCallSignatures6.js b/tests/baselines/reference/assignmentCompatWithCallSignatures6.js
index a29a607f9ef..e57a5ac07a0 100644
--- a/tests/baselines/reference/assignmentCompatWithCallSignatures6.js
+++ b/tests/baselines/reference/assignmentCompatWithCallSignatures6.js
@@ -47,8 +47,7 @@ b16 = x.a16;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/assignmentCompatWithConstructSignatures3.js b/tests/baselines/reference/assignmentCompatWithConstructSignatures3.js
index 32176e764e9..d02c635c584 100644
--- a/tests/baselines/reference/assignmentCompatWithConstructSignatures3.js
+++ b/tests/baselines/reference/assignmentCompatWithConstructSignatures3.js
@@ -104,8 +104,7 @@ b18 = a18; // ok
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/assignmentCompatWithConstructSignatures4.js b/tests/baselines/reference/assignmentCompatWithConstructSignatures4.js
index 21bace1645c..6f9f20333f2 100644
--- a/tests/baselines/reference/assignmentCompatWithConstructSignatures4.js
+++ b/tests/baselines/reference/assignmentCompatWithConstructSignatures4.js
@@ -103,8 +103,7 @@ module Errors {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Errors;
 (function (Errors) {
diff --git a/tests/baselines/reference/assignmentCompatWithConstructSignatures5.js b/tests/baselines/reference/assignmentCompatWithConstructSignatures5.js
index 76be317e95a..bd4c73e65dd 100644
--- a/tests/baselines/reference/assignmentCompatWithConstructSignatures5.js
+++ b/tests/baselines/reference/assignmentCompatWithConstructSignatures5.js
@@ -70,8 +70,7 @@ b18 = a18; // ok
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/assignmentCompatWithConstructSignatures6.js b/tests/baselines/reference/assignmentCompatWithConstructSignatures6.js
index dc1d0dd2dee..98477fa1523 100644
--- a/tests/baselines/reference/assignmentCompatWithConstructSignatures6.js
+++ b/tests/baselines/reference/assignmentCompatWithConstructSignatures6.js
@@ -47,8 +47,7 @@ b16 = x.a16;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/assignmentCompatWithNumericIndexer.js b/tests/baselines/reference/assignmentCompatWithNumericIndexer.js
index 6044c40b3cc..617d136bbb2 100644
--- a/tests/baselines/reference/assignmentCompatWithNumericIndexer.js
+++ b/tests/baselines/reference/assignmentCompatWithNumericIndexer.js
@@ -48,8 +48,7 @@ module Generics {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/assignmentCompatWithNumericIndexer3.js b/tests/baselines/reference/assignmentCompatWithNumericIndexer3.js
index b3c073ea0b7..0c5b0be038f 100644
--- a/tests/baselines/reference/assignmentCompatWithNumericIndexer3.js
+++ b/tests/baselines/reference/assignmentCompatWithNumericIndexer3.js
@@ -45,8 +45,7 @@ module Generics {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/assignmentCompatWithObjectMembers4.js b/tests/baselines/reference/assignmentCompatWithObjectMembers4.js
index 229525a91f0..20279fb1dc5 100644
--- a/tests/baselines/reference/assignmentCompatWithObjectMembers4.js
+++ b/tests/baselines/reference/assignmentCompatWithObjectMembers4.js
@@ -96,8 +96,7 @@ module WithBase {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var OnlyDerived;
 (function (OnlyDerived) {
diff --git a/tests/baselines/reference/assignmentCompatWithObjectMembersOptionality.js b/tests/baselines/reference/assignmentCompatWithObjectMembersOptionality.js
index 629f7bf5113..6675fab6d69 100644
--- a/tests/baselines/reference/assignmentCompatWithObjectMembersOptionality.js
+++ b/tests/baselines/reference/assignmentCompatWithObjectMembersOptionality.js
@@ -93,8 +93,7 @@ module SourceHasOptional {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/assignmentCompatWithObjectMembersOptionality2.js b/tests/baselines/reference/assignmentCompatWithObjectMembersOptionality2.js
index 4ffec4aa7dd..b89106eba2b 100644
--- a/tests/baselines/reference/assignmentCompatWithObjectMembersOptionality2.js
+++ b/tests/baselines/reference/assignmentCompatWithObjectMembersOptionality2.js
@@ -95,8 +95,7 @@ module SourceHasOptional {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/assignmentCompatWithStringIndexer.js b/tests/baselines/reference/assignmentCompatWithStringIndexer.js
index 99457453af4..3391ac5773a 100644
--- a/tests/baselines/reference/assignmentCompatWithStringIndexer.js
+++ b/tests/baselines/reference/assignmentCompatWithStringIndexer.js
@@ -58,8 +58,7 @@ module Generics {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/assignmentLHSIsValue.js b/tests/baselines/reference/assignmentLHSIsValue.js
index 33054009d8e..127f85512ac 100644
--- a/tests/baselines/reference/assignmentLHSIsValue.js
+++ b/tests/baselines/reference/assignmentLHSIsValue.js
@@ -74,8 +74,7 @@ foo() = value;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // expected error for all the LHS of assignments
 var value;
diff --git a/tests/baselines/reference/autolift4.js b/tests/baselines/reference/autolift4.js
index 5986ef4a3f5..f4bbad50c60 100644
--- a/tests/baselines/reference/autolift4.js
+++ b/tests/baselines/reference/autolift4.js
@@ -27,8 +27,7 @@ class Point3D extends Point {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Point = (function () {
     function Point(x, y) {
diff --git a/tests/baselines/reference/baseCheck.js b/tests/baselines/reference/baseCheck.js
index 4e7db8e6a5b..49038f37b18 100644
--- a/tests/baselines/reference/baseCheck.js
+++ b/tests/baselines/reference/baseCheck.js
@@ -33,8 +33,7 @@ function f() {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C(x, y) {
diff --git a/tests/baselines/reference/baseIndexSignatureResolution.js b/tests/baselines/reference/baseIndexSignatureResolution.js
index 85b76221e3c..8463ed58a53 100644
--- a/tests/baselines/reference/baseIndexSignatureResolution.js
+++ b/tests/baselines/reference/baseIndexSignatureResolution.js
@@ -28,8 +28,7 @@ var z: Derived = b.foo();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/baseTypeOrderChecking.js b/tests/baselines/reference/baseTypeOrderChecking.js
index 754d90e21ea..4c5fe22ea08 100644
--- a/tests/baselines/reference/baseTypeOrderChecking.js
+++ b/tests/baselines/reference/baseTypeOrderChecking.js
@@ -40,8 +40,7 @@ class Class4<T> extends Class3<T>
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var someVariable;
 var Class1 = (function () {
diff --git a/tests/baselines/reference/baseTypeWrappingInstantiationChain.js b/tests/baselines/reference/baseTypeWrappingInstantiationChain.js
index aaa93710339..1de1ebd4bfb 100644
--- a/tests/baselines/reference/baseTypeWrappingInstantiationChain.js
+++ b/tests/baselines/reference/baseTypeWrappingInstantiationChain.js
@@ -30,8 +30,7 @@ class Wrapper<T5> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/bases.js b/tests/baselines/reference/bases.js
index 5687e9e0fe1..0275c225dac 100644
--- a/tests/baselines/reference/bases.js
+++ b/tests/baselines/reference/bases.js
@@ -24,8 +24,7 @@ new C().y;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var B = (function () {
     function B() {
diff --git a/tests/baselines/reference/bestCommonTypeOfConditionalExpressions.js b/tests/baselines/reference/bestCommonTypeOfConditionalExpressions.js
index e56e530ad64..abd2cc5e874 100644
--- a/tests/baselines/reference/bestCommonTypeOfConditionalExpressions.js
+++ b/tests/baselines/reference/bestCommonTypeOfConditionalExpressions.js
@@ -32,8 +32,7 @@ function foo5<T, U>(t: T, u: U): Object {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a;
 var b;
diff --git a/tests/baselines/reference/bestCommonTypeOfConditionalExpressions2.js b/tests/baselines/reference/bestCommonTypeOfConditionalExpressions2.js
index fb3c15a8fba..e0e7bc3f324 100644
--- a/tests/baselines/reference/bestCommonTypeOfConditionalExpressions2.js
+++ b/tests/baselines/reference/bestCommonTypeOfConditionalExpressions2.js
@@ -30,8 +30,7 @@ function foo3<T extends U, U extends V, V>(t: T, u: U) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/bestCommonTypeOfTuple2.js b/tests/baselines/reference/bestCommonTypeOfTuple2.js
index 5642df5570c..ed0b0ecb328 100644
--- a/tests/baselines/reference/bestCommonTypeOfTuple2.js
+++ b/tests/baselines/reference/bestCommonTypeOfTuple2.js
@@ -26,8 +26,7 @@ var e51 = t5[2]; // {}
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/callSignatureAssignabilityInInheritance2.js b/tests/baselines/reference/callSignatureAssignabilityInInheritance2.js
index 685e33acb6b..e43c22fab75 100644
--- a/tests/baselines/reference/callSignatureAssignabilityInInheritance2.js
+++ b/tests/baselines/reference/callSignatureAssignabilityInInheritance2.js
@@ -74,8 +74,7 @@ interface I extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/callSignatureAssignabilityInInheritance3.js b/tests/baselines/reference/callSignatureAssignabilityInInheritance3.js
index 135c0c056ae..6105ddf23fa 100644
--- a/tests/baselines/reference/callSignatureAssignabilityInInheritance3.js
+++ b/tests/baselines/reference/callSignatureAssignabilityInInheritance3.js
@@ -119,8 +119,7 @@ module Errors {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Errors;
 (function (Errors) {
diff --git a/tests/baselines/reference/callSignatureAssignabilityInInheritance4.js b/tests/baselines/reference/callSignatureAssignabilityInInheritance4.js
index c578a49ee55..aee3af6f740 100644
--- a/tests/baselines/reference/callSignatureAssignabilityInInheritance4.js
+++ b/tests/baselines/reference/callSignatureAssignabilityInInheritance4.js
@@ -54,8 +54,7 @@ interface I extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/callSignatureAssignabilityInInheritance5.js b/tests/baselines/reference/callSignatureAssignabilityInInheritance5.js
index 74987308ef7..c72a77e4020 100644
--- a/tests/baselines/reference/callSignatureAssignabilityInInheritance5.js
+++ b/tests/baselines/reference/callSignatureAssignabilityInInheritance5.js
@@ -54,8 +54,7 @@ interface I extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/callSignatureAssignabilityInInheritance6.js b/tests/baselines/reference/callSignatureAssignabilityInInheritance6.js
index aa2e9787bd1..e22bb1189ed 100644
--- a/tests/baselines/reference/callSignatureAssignabilityInInheritance6.js
+++ b/tests/baselines/reference/callSignatureAssignabilityInInheritance6.js
@@ -57,8 +57,7 @@ interface I9<T> extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/callWithSpread.js b/tests/baselines/reference/callWithSpread.js
index d21b4879daa..50840abfbb7 100644
--- a/tests/baselines/reference/callWithSpread.js
+++ b/tests/baselines/reference/callWithSpread.js
@@ -54,8 +54,7 @@ class D extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function foo(x, y) {
     var z = [];
diff --git a/tests/baselines/reference/captureThisInSuperCall.js b/tests/baselines/reference/captureThisInSuperCall.js
index 27c80e2991d..611ad93f531 100644
--- a/tests/baselines/reference/captureThisInSuperCall.js
+++ b/tests/baselines/reference/captureThisInSuperCall.js
@@ -12,8 +12,7 @@ class B extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A(p) {
diff --git a/tests/baselines/reference/castingTuple.js b/tests/baselines/reference/castingTuple.js
index 8b1005d4487..0102d1310a3 100644
--- a/tests/baselines/reference/castingTuple.js
+++ b/tests/baselines/reference/castingTuple.js
@@ -36,8 +36,7 @@ t4[2] = 10;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/chainedAssignment3.js b/tests/baselines/reference/chainedAssignment3.js
index 022668ba7cf..04c328031cd 100644
--- a/tests/baselines/reference/chainedAssignment3.js
+++ b/tests/baselines/reference/chainedAssignment3.js
@@ -26,8 +26,7 @@ a = b = new A();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/chainedCallsWithTypeParameterConstrainedToOtherTypeParameter.js b/tests/baselines/reference/chainedCallsWithTypeParameterConstrainedToOtherTypeParameter.js
index 494f0bc1b5d..e7e1a3a871b 100644
--- a/tests/baselines/reference/chainedCallsWithTypeParameterConstrainedToOtherTypeParameter.js
+++ b/tests/baselines/reference/chainedCallsWithTypeParameterConstrainedToOtherTypeParameter.js
@@ -23,8 +23,7 @@ class C extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Chain = (function () {
     function Chain(value) {
diff --git a/tests/baselines/reference/checkForObjectTooStrict.js b/tests/baselines/reference/checkForObjectTooStrict.js
index bcdde6b3be1..d8f40a3f1d9 100644
--- a/tests/baselines/reference/checkForObjectTooStrict.js
+++ b/tests/baselines/reference/checkForObjectTooStrict.js
@@ -35,8 +35,7 @@ class Baz extends Object {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo;
 (function (Foo) {
diff --git a/tests/baselines/reference/circularImportAlias.js b/tests/baselines/reference/circularImportAlias.js
index 1a50a46221b..8b908a97ee6 100644
--- a/tests/baselines/reference/circularImportAlias.js
+++ b/tests/baselines/reference/circularImportAlias.js
@@ -24,8 +24,7 @@ var c = new B.a.C();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var B;
 (function (B) {
diff --git a/tests/baselines/reference/classConstructorParametersAccessibility.js b/tests/baselines/reference/classConstructorParametersAccessibility.js
index 5d715556ec1..a5538b66ecc 100644
--- a/tests/baselines/reference/classConstructorParametersAccessibility.js
+++ b/tests/baselines/reference/classConstructorParametersAccessibility.js
@@ -30,8 +30,7 @@ class Derived extends C3 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function () {
     function C1(x) {
diff --git a/tests/baselines/reference/classConstructorParametersAccessibility2.js b/tests/baselines/reference/classConstructorParametersAccessibility2.js
index 1d273e119ec..581746a180b 100644
--- a/tests/baselines/reference/classConstructorParametersAccessibility2.js
+++ b/tests/baselines/reference/classConstructorParametersAccessibility2.js
@@ -30,8 +30,7 @@ class Derived extends C3 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function () {
     function C1(x) {
diff --git a/tests/baselines/reference/classConstructorParametersAccessibility3.js b/tests/baselines/reference/classConstructorParametersAccessibility3.js
index 43823bbb4d9..d98b094ccdb 100644
--- a/tests/baselines/reference/classConstructorParametersAccessibility3.js
+++ b/tests/baselines/reference/classConstructorParametersAccessibility3.js
@@ -17,8 +17,7 @@ d.p;  // public, OK
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(p) {
diff --git a/tests/baselines/reference/classDeclarationMergedInModuleWithContinuation.js b/tests/baselines/reference/classDeclarationMergedInModuleWithContinuation.js
index 7299b04720f..a8d6fcd88e0 100644
--- a/tests/baselines/reference/classDeclarationMergedInModuleWithContinuation.js
+++ b/tests/baselines/reference/classDeclarationMergedInModuleWithContinuation.js
@@ -15,8 +15,7 @@ module M {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/classDoesNotDependOnBaseTypes.js b/tests/baselines/reference/classDoesNotDependOnBaseTypes.js
index 52474582315..8515e1d98eb 100644
--- a/tests/baselines/reference/classDoesNotDependOnBaseTypes.js
+++ b/tests/baselines/reference/classDoesNotDependOnBaseTypes.js
@@ -16,8 +16,7 @@ class StringTreeCollection extends StringTreeCollectionBase { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var x;
 if (typeof x !== "string") {
diff --git a/tests/baselines/reference/classExtendingBuiltinType.js b/tests/baselines/reference/classExtendingBuiltinType.js
index 666ada39505..8a4b0dd3849 100644
--- a/tests/baselines/reference/classExtendingBuiltinType.js
+++ b/tests/baselines/reference/classExtendingBuiltinType.js
@@ -15,8 +15,7 @@ class C10 extends Array<number> { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function (_super) {
     __extends(C1, _super);
diff --git a/tests/baselines/reference/classExtendingClass.js b/tests/baselines/reference/classExtendingClass.js
index b8e079e8ecb..6168cb3418d 100644
--- a/tests/baselines/reference/classExtendingClass.js
+++ b/tests/baselines/reference/classExtendingClass.js
@@ -35,8 +35,7 @@ var r8 = D2.other(1);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/classExtendingClassLikeType.js b/tests/baselines/reference/classExtendingClassLikeType.js
index 88a5dc8dcd3..4634b22e493 100644
--- a/tests/baselines/reference/classExtendingClassLikeType.js
+++ b/tests/baselines/reference/classExtendingClassLikeType.js
@@ -62,8 +62,7 @@ class D5 extends getBadBase() {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // Error, no Base constructor function
 var D0 = (function (_super) {
diff --git a/tests/baselines/reference/classExtendingNonConstructor.errors.txt b/tests/baselines/reference/classExtendingNonConstructor.errors.txt
index b1e3994cf1c..17b3610d252 100644
--- a/tests/baselines/reference/classExtendingNonConstructor.errors.txt
+++ b/tests/baselines/reference/classExtendingNonConstructor.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(7,18): error TS2507: Base expression is not of a constructor function type.
-tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(8,18): error TS2507: Base expression is not of a constructor function type.
-tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(9,18): error TS2507: Base expression is not of a constructor function type.
-tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(10,18): error TS2507: Base expression is not of a constructor function type.
-tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(11,18): error TS2507: Base expression is not of a constructor function type.
-tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(12,18): error TS2507: Base expression is not of a constructor function type.
-tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(13,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(7,18): error TS2507: Type 'undefined' is not a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(8,18): error TS2507: Type 'boolean' is not a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(9,18): error TS2507: Type 'boolean' is not a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(10,18): error TS2507: Type 'number' is not a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(11,18): error TS2507: Type 'string' is not a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(12,18): error TS2507: Type '{}' is not a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(13,18): error TS2507: Type '() => void' is not a constructor function type.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts (7 errors) ====
@@ -16,23 +16,23 @@ tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.t
     
     class C1 extends undefined { }
                      ~~~~~~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'undefined' is not a constructor function type.
     class C2 extends true { }
                      ~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'boolean' is not a constructor function type.
     class C3 extends false { }
                      ~~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'boolean' is not a constructor function type.
     class C4 extends 42 { }
                      ~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'number' is not a constructor function type.
     class C5 extends "hello" { }
                      ~~~~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'string' is not a constructor function type.
     class C6 extends x { }
                      ~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type '{}' is not a constructor function type.
     class C7 extends foo { }
                      ~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type '() => void' is not a constructor function type.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/classExtendingNonConstructor.js b/tests/baselines/reference/classExtendingNonConstructor.js
index f796b30ddd6..dff2fdf9ca9 100644
--- a/tests/baselines/reference/classExtendingNonConstructor.js
+++ b/tests/baselines/reference/classExtendingNonConstructor.js
@@ -18,8 +18,7 @@ class C7 extends foo { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var x;
 function foo() {
diff --git a/tests/baselines/reference/classExtendingNull.js b/tests/baselines/reference/classExtendingNull.js
index f0c3ea69626..ac8009b9cd9 100644
--- a/tests/baselines/reference/classExtendingNull.js
+++ b/tests/baselines/reference/classExtendingNull.js
@@ -7,8 +7,7 @@ class C2 extends (null) { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function (_super) {
     __extends(C1, _super);
diff --git a/tests/baselines/reference/classExtendingPrimitive.errors.txt b/tests/baselines/reference/classExtendingPrimitive.errors.txt
index 68525a1eabd..554e0fbecbc 100644
--- a/tests/baselines/reference/classExtendingPrimitive.errors.txt
+++ b/tests/baselines/reference/classExtendingPrimitive.errors.txt
@@ -4,9 +4,9 @@ tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/cla
 tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingPrimitive.ts(6,18): error TS2304: Cannot find name 'Void'.
 tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingPrimitive.ts(7,19): error TS1109: Expression expected.
 tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingPrimitive.ts(8,18): error TS2304: Cannot find name 'Null'.
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingPrimitive.ts(10,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingPrimitive.ts(10,18): error TS2507: Type 'undefined' is not a constructor function type.
 tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingPrimitive.ts(11,18): error TS2304: Cannot find name 'Undefined'.
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingPrimitive.ts(14,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingPrimitive.ts(14,18): error TS2507: Type 'typeof E' is not a constructor function type.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendingPrimitive.ts (9 errors) ====
@@ -33,7 +33,7 @@ tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/cla
     class C5a extends null { }
     class C6 extends undefined { }
                      ~~~~~~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'undefined' is not a constructor function type.
     class C7 extends Undefined { }
                      ~~~~~~~~~
 !!! error TS2304: Cannot find name 'Undefined'.
@@ -41,4 +41,4 @@ tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/cla
     enum E { A }
     class C8 extends E { }
                      ~
-!!! error TS2507: Base expression is not of a constructor function type.
\ No newline at end of file
+!!! error TS2507: Type 'typeof E' is not a constructor function type.
\ No newline at end of file
diff --git a/tests/baselines/reference/classExtendingPrimitive.js b/tests/baselines/reference/classExtendingPrimitive.js
index b099ce763e8..cafa4eebcd1 100644
--- a/tests/baselines/reference/classExtendingPrimitive.js
+++ b/tests/baselines/reference/classExtendingPrimitive.js
@@ -19,8 +19,7 @@ class C8 extends E { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/classExtendingPrimitive2.js b/tests/baselines/reference/classExtendingPrimitive2.js
index 3dcff0b44b9..4661ab961c9 100644
--- a/tests/baselines/reference/classExtendingPrimitive2.js
+++ b/tests/baselines/reference/classExtendingPrimitive2.js
@@ -9,8 +9,7 @@ class C5a extends null { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C4a = (function () {
     function C4a() {
diff --git a/tests/baselines/reference/classExtendingQualifiedName.js b/tests/baselines/reference/classExtendingQualifiedName.js
index 0289797d1e3..44a4fbe2bd6 100644
--- a/tests/baselines/reference/classExtendingQualifiedName.js
+++ b/tests/baselines/reference/classExtendingQualifiedName.js
@@ -11,8 +11,7 @@ module M {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/classExtendingQualifiedName2.js b/tests/baselines/reference/classExtendingQualifiedName2.js
index 76065ccc577..afd432180d4 100644
--- a/tests/baselines/reference/classExtendingQualifiedName2.js
+++ b/tests/baselines/reference/classExtendingQualifiedName2.js
@@ -11,8 +11,7 @@ module M {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/classExtendsClauseClassMergedWithModuleNotReferingConstructor.errors.txt b/tests/baselines/reference/classExtendsClauseClassMergedWithModuleNotReferingConstructor.errors.txt
index b1c5d253b56..dfac4f68885 100644
--- a/tests/baselines/reference/classExtendsClauseClassMergedWithModuleNotReferingConstructor.errors.txt
+++ b/tests/baselines/reference/classExtendsClauseClassMergedWithModuleNotReferingConstructor.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/classExtendsClauseClassMergedWithModuleNotReferingConstructor.ts(10,21): error TS2507: Base expression is not of a constructor function type.
+tests/cases/compiler/classExtendsClauseClassMergedWithModuleNotReferingConstructor.ts(10,21): error TS2507: Type 'number' is not a constructor function type.
 
 
 ==== tests/cases/compiler/classExtendsClauseClassMergedWithModuleNotReferingConstructor.ts (1 errors) ====
@@ -13,7 +13,7 @@ tests/cases/compiler/classExtendsClauseClassMergedWithModuleNotReferingConstruct
         var A = 1;
         class B extends A {
                         ~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'number' is not a constructor function type.
             b: string;
         }
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/classExtendsClauseClassMergedWithModuleNotReferingConstructor.js b/tests/baselines/reference/classExtendsClauseClassMergedWithModuleNotReferingConstructor.js
index 726f918f4e8..fe8dc79b864 100644
--- a/tests/baselines/reference/classExtendsClauseClassMergedWithModuleNotReferingConstructor.js
+++ b/tests/baselines/reference/classExtendsClauseClassMergedWithModuleNotReferingConstructor.js
@@ -17,8 +17,7 @@ module Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/classExtendsClauseClassNotReferringConstructor.errors.txt b/tests/baselines/reference/classExtendsClauseClassNotReferringConstructor.errors.txt
index 448167d739d..ff355ec653c 100644
--- a/tests/baselines/reference/classExtendsClauseClassNotReferringConstructor.errors.txt
+++ b/tests/baselines/reference/classExtendsClauseClassNotReferringConstructor.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/classExtendsClauseClassNotReferringConstructor.ts(4,21): error TS2507: Base expression is not of a constructor function type.
+tests/cases/compiler/classExtendsClauseClassNotReferringConstructor.ts(4,21): error TS2507: Type 'number' is not a constructor function type.
 
 
 ==== tests/cases/compiler/classExtendsClauseClassNotReferringConstructor.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/classExtendsClauseClassNotReferringConstructor.ts(4,21): er
         var A = 1;
         class B extends A { b: string; }
                         ~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'number' is not a constructor function type.
     }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/classExtendsClauseClassNotReferringConstructor.js b/tests/baselines/reference/classExtendsClauseClassNotReferringConstructor.js
index 8dc3410a179..94c50679151 100644
--- a/tests/baselines/reference/classExtendsClauseClassNotReferringConstructor.js
+++ b/tests/baselines/reference/classExtendsClauseClassNotReferringConstructor.js
@@ -10,8 +10,7 @@ module Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/classExtendsEveryObjectType.errors.txt b/tests/baselines/reference/classExtendsEveryObjectType.errors.txt
index e1f1c785bbc..0339dfad13a 100644
--- a/tests/baselines/reference/classExtendsEveryObjectType.errors.txt
+++ b/tests/baselines/reference/classExtendsEveryObjectType.errors.txt
@@ -1,11 +1,11 @@
 tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(4,17): error TS2304: Cannot find name 'I'.
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(6,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(6,18): error TS2507: Type '{ foo: any; }' is not a constructor function type.
 tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(6,25): error TS2304: Cannot find name 'string'.
 tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(6,31): error TS1005: ',' expected.
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(8,18): error TS2507: Base expression is not of a constructor function type.
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(11,18): error TS2507: Base expression is not of a constructor function type.
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(14,18): error TS2507: Base expression is not of a constructor function type.
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(16,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(8,18): error TS2507: Type '{ foo: string; }' is not a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(11,18): error TS2507: Type 'typeof M' is not a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(14,18): error TS2507: Type '() => void' is not a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts(16,18): error TS2507: Type 'undefined[]' is not a constructor function type.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType.ts (8 errors) ====
@@ -18,7 +18,7 @@ tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/cla
     
     class C2 extends { foo: string; } { } // error
                      ~~~~~~~~~~~~~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type '{ foo: any; }' is not a constructor function type.
                             ~~~~~~
 !!! error TS2304: Cannot find name 'string'.
                                   ~
@@ -26,18 +26,18 @@ tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/cla
     var x: { foo: string; }
     class C3 extends x { } // error
                      ~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type '{ foo: string; }' is not a constructor function type.
     
     module M { export var x = 1; }
     class C4 extends M { } // error
                      ~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'typeof M' is not a constructor function type.
     
     function foo() { }
     class C5 extends foo { } // error
                      ~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type '() => void' is not a constructor function type.
     
     class C6 extends []{ } // error
                      ~~
-!!! error TS2507: Base expression is not of a constructor function type.
\ No newline at end of file
+!!! error TS2507: Type 'undefined[]' is not a constructor function type.
\ No newline at end of file
diff --git a/tests/baselines/reference/classExtendsEveryObjectType.js b/tests/baselines/reference/classExtendsEveryObjectType.js
index afbb4dab714..92414c7e6c3 100644
--- a/tests/baselines/reference/classExtendsEveryObjectType.js
+++ b/tests/baselines/reference/classExtendsEveryObjectType.js
@@ -20,8 +20,7 @@ class C6 extends []{ } // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/classExtendsEveryObjectType2.errors.txt b/tests/baselines/reference/classExtendsEveryObjectType2.errors.txt
index 650c4e4886e..af52a248b54 100644
--- a/tests/baselines/reference/classExtendsEveryObjectType2.errors.txt
+++ b/tests/baselines/reference/classExtendsEveryObjectType2.errors.txt
@@ -1,13 +1,13 @@
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType2.ts(1,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType2.ts(1,18): error TS2507: Type '{ foo: any; }' is not a constructor function type.
 tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType2.ts(1,25): error TS2304: Cannot find name 'string'.
 tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType2.ts(1,31): error TS1005: ',' expected.
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType2.ts(3,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType2.ts(3,18): error TS2507: Type 'undefined[]' is not a constructor function type.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsEveryObjectType2.ts (4 errors) ====
     class C2 extends { foo: string; } { } // error
                      ~~~~~~~~~~~~~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type '{ foo: any; }' is not a constructor function type.
                             ~~~~~~
 !!! error TS2304: Cannot find name 'string'.
                                   ~
@@ -15,4 +15,4 @@ tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/cla
     
     class C6 extends []{ } // error
                      ~~
-!!! error TS2507: Base expression is not of a constructor function type.
\ No newline at end of file
+!!! error TS2507: Type 'undefined[]' is not a constructor function type.
\ No newline at end of file
diff --git a/tests/baselines/reference/classExtendsEveryObjectType2.js b/tests/baselines/reference/classExtendsEveryObjectType2.js
index c41943072dd..2735032f3c4 100644
--- a/tests/baselines/reference/classExtendsEveryObjectType2.js
+++ b/tests/baselines/reference/classExtendsEveryObjectType2.js
@@ -7,8 +7,7 @@ class C6 extends []{ } // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C2 = (function (_super) {
     __extends(C2, _super);
diff --git a/tests/baselines/reference/classExtendsInterface.js b/tests/baselines/reference/classExtendsInterface.js
index a3e596299fa..9b78cde35e9 100644
--- a/tests/baselines/reference/classExtendsInterface.js
+++ b/tests/baselines/reference/classExtendsInterface.js
@@ -12,8 +12,7 @@ class B2<T> implements Comparable2<T> {}
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function (_super) {
     __extends(A, _super);
diff --git a/tests/baselines/reference/classExtendsItself.js b/tests/baselines/reference/classExtendsItself.js
index 79a4226731f..c370e797a57 100644
--- a/tests/baselines/reference/classExtendsItself.js
+++ b/tests/baselines/reference/classExtendsItself.js
@@ -9,8 +9,7 @@ class E<T> extends E<string> { } // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/classExtendsItselfIndirectly.js b/tests/baselines/reference/classExtendsItselfIndirectly.js
index eee52b877e3..65cd72ce3c8 100644
--- a/tests/baselines/reference/classExtendsItselfIndirectly.js
+++ b/tests/baselines/reference/classExtendsItselfIndirectly.js
@@ -15,8 +15,7 @@ class E2<T> extends D2<T> { baz: T; }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/classExtendsItselfIndirectly2.js b/tests/baselines/reference/classExtendsItselfIndirectly2.js
index 02201425cba..c0b46e6cbb6 100644
--- a/tests/baselines/reference/classExtendsItselfIndirectly2.js
+++ b/tests/baselines/reference/classExtendsItselfIndirectly2.js
@@ -26,8 +26,7 @@ module O {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/classExtendsItselfIndirectly3.js b/tests/baselines/reference/classExtendsItselfIndirectly3.js
index bff6dd92bc9..9241403a7ce 100644
--- a/tests/baselines/reference/classExtendsItselfIndirectly3.js
+++ b/tests/baselines/reference/classExtendsItselfIndirectly3.js
@@ -22,8 +22,7 @@ class E2<T> extends D2<T> { baz: T; }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
@@ -36,8 +35,7 @@ var C = (function (_super) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var D = (function (_super) {
     __extends(D, _super);
@@ -50,8 +48,7 @@ var D = (function (_super) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var E = (function (_super) {
     __extends(E, _super);
@@ -64,8 +61,7 @@ var E = (function (_super) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C2 = (function (_super) {
     __extends(C2, _super);
@@ -78,8 +74,7 @@ var C2 = (function (_super) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var D2 = (function (_super) {
     __extends(D2, _super);
@@ -92,8 +87,7 @@ var D2 = (function (_super) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var E2 = (function (_super) {
     __extends(E2, _super);
diff --git a/tests/baselines/reference/classExtendsMultipleBaseClasses.js b/tests/baselines/reference/classExtendsMultipleBaseClasses.js
index 7027e85450d..d1ffee30415 100644
--- a/tests/baselines/reference/classExtendsMultipleBaseClasses.js
+++ b/tests/baselines/reference/classExtendsMultipleBaseClasses.js
@@ -7,8 +7,7 @@ class C extends A,B { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/classExtendsShadowedConstructorFunction.errors.txt b/tests/baselines/reference/classExtendsShadowedConstructorFunction.errors.txt
index 475a980e4e6..3d8c7454255 100644
--- a/tests/baselines/reference/classExtendsShadowedConstructorFunction.errors.txt
+++ b/tests/baselines/reference/classExtendsShadowedConstructorFunction.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsShadowedConstructorFunction.ts(5,21): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsShadowedConstructorFunction.ts(5,21): error TS2507: Type 'number' is not a constructor function type.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsShadowedConstructorFunction.ts (1 errors) ====
@@ -8,7 +8,7 @@ tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/cla
         var C = 1;
         class D extends C { // error, C must evaluate to constructor function
                         ~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'number' is not a constructor function type.
             bar: string;
         }
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/classExtendsShadowedConstructorFunction.js b/tests/baselines/reference/classExtendsShadowedConstructorFunction.js
index 48f2e791139..164ffdc8493 100644
--- a/tests/baselines/reference/classExtendsShadowedConstructorFunction.js
+++ b/tests/baselines/reference/classExtendsShadowedConstructorFunction.js
@@ -12,8 +12,7 @@ module M {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/classExtendsValidConstructorFunction.errors.txt b/tests/baselines/reference/classExtendsValidConstructorFunction.errors.txt
index 6ebd818e547..fdfd9110ce6 100644
--- a/tests/baselines/reference/classExtendsValidConstructorFunction.errors.txt
+++ b/tests/baselines/reference/classExtendsValidConstructorFunction.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsValidConstructorFunction.ts(5,17): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsValidConstructorFunction.ts(5,17): error TS2507: Type '() => void' is not a constructor function type.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classExtendsValidConstructorFunction.ts (1 errors) ====
@@ -8,4 +8,4 @@ tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/cla
     
     class C extends foo { } // error, cannot extend it though
                     ~~~
-!!! error TS2507: Base expression is not of a constructor function type.
\ No newline at end of file
+!!! error TS2507: Type '() => void' is not a constructor function type.
\ No newline at end of file
diff --git a/tests/baselines/reference/classExtendsValidConstructorFunction.js b/tests/baselines/reference/classExtendsValidConstructorFunction.js
index 411bd3c2fba..448db68db9f 100644
--- a/tests/baselines/reference/classExtendsValidConstructorFunction.js
+++ b/tests/baselines/reference/classExtendsValidConstructorFunction.js
@@ -9,8 +9,7 @@ class C extends foo { } // error, cannot extend it though
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function foo() { }
 var x = new foo(); // can be used as a constructor function
diff --git a/tests/baselines/reference/classHeritageWithTrailingSeparator.js b/tests/baselines/reference/classHeritageWithTrailingSeparator.js
index 6d33f79a4d5..2d5b12d5201 100644
--- a/tests/baselines/reference/classHeritageWithTrailingSeparator.js
+++ b/tests/baselines/reference/classHeritageWithTrailingSeparator.js
@@ -7,8 +7,7 @@ class D extends C, {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/classImplementsClass2.js b/tests/baselines/reference/classImplementsClass2.js
index 49b73bfdb18..490d2706b48 100644
--- a/tests/baselines/reference/classImplementsClass2.js
+++ b/tests/baselines/reference/classImplementsClass2.js
@@ -17,8 +17,7 @@ c2 = c;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/classImplementsClass3.js b/tests/baselines/reference/classImplementsClass3.js
index f8773b435bd..00cb49e2da3 100644
--- a/tests/baselines/reference/classImplementsClass3.js
+++ b/tests/baselines/reference/classImplementsClass3.js
@@ -18,8 +18,7 @@ c2 = c;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/classImplementsClass4.js b/tests/baselines/reference/classImplementsClass4.js
index cf442b0ad24..0d7508b723b 100644
--- a/tests/baselines/reference/classImplementsClass4.js
+++ b/tests/baselines/reference/classImplementsClass4.js
@@ -20,8 +20,7 @@ c2 = c;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/classImplementsClass5.js b/tests/baselines/reference/classImplementsClass5.js
index a648f6bd63f..caacb7b3044 100644
--- a/tests/baselines/reference/classImplementsClass5.js
+++ b/tests/baselines/reference/classImplementsClass5.js
@@ -21,8 +21,7 @@ c2 = c;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/classImplementsClass6.js b/tests/baselines/reference/classImplementsClass6.js
index af6f0844d28..2e8d765be89 100644
--- a/tests/baselines/reference/classImplementsClass6.js
+++ b/tests/baselines/reference/classImplementsClass6.js
@@ -25,8 +25,7 @@ c2.bar(); // should error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/classIndexer3.js b/tests/baselines/reference/classIndexer3.js
index 9f630b96306..e962c7295f2 100644
--- a/tests/baselines/reference/classIndexer3.js
+++ b/tests/baselines/reference/classIndexer3.js
@@ -14,8 +14,7 @@ class D123 extends C123 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C123 = (function () {
     function C123() {
diff --git a/tests/baselines/reference/classInheritence.js b/tests/baselines/reference/classInheritence.js
index 374248c3a2c..1e463dd195d 100644
--- a/tests/baselines/reference/classInheritence.js
+++ b/tests/baselines/reference/classInheritence.js
@@ -6,8 +6,7 @@ class A extends A { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var B = (function (_super) {
     __extends(B, _super);
diff --git a/tests/baselines/reference/classIsSubtypeOfBaseType.js b/tests/baselines/reference/classIsSubtypeOfBaseType.js
index a33bf5499be..a92cfb430bf 100644
--- a/tests/baselines/reference/classIsSubtypeOfBaseType.js
+++ b/tests/baselines/reference/classIsSubtypeOfBaseType.js
@@ -19,8 +19,7 @@ class Derived2 extends Base<{ bar: string; }> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/classMemberWithMissingIdentifier.errors.txt b/tests/baselines/reference/classMemberWithMissingIdentifier.errors.txt
new file mode 100644
index 00000000000..4bbc2d8167d
--- /dev/null
+++ b/tests/baselines/reference/classMemberWithMissingIdentifier.errors.txt
@@ -0,0 +1,12 @@
+tests/cases/compiler/classMemberWithMissingIdentifier.ts(2,11): error TS1146: Declaration expected.
+tests/cases/compiler/classMemberWithMissingIdentifier.ts(2,12): error TS1005: '=' expected.
+
+
+==== tests/cases/compiler/classMemberWithMissingIdentifier.ts (2 errors) ====
+    class C { 
+        public {};
+              
+!!! error TS1146: Declaration expected.
+               ~
+!!! error TS1005: '=' expected.
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/classMemberWithMissingIdentifier.js b/tests/baselines/reference/classMemberWithMissingIdentifier.js
new file mode 100644
index 00000000000..cd1825d0da0
--- /dev/null
+++ b/tests/baselines/reference/classMemberWithMissingIdentifier.js
@@ -0,0 +1,12 @@
+//// [classMemberWithMissingIdentifier.ts]
+class C { 
+    public {};
+}
+
+//// [classMemberWithMissingIdentifier.js]
+var C = (function () {
+    function C() {
+        this. = {};
+    }
+    return C;
+})();
diff --git a/tests/baselines/reference/classMemberWithMissingIdentifier2.errors.txt b/tests/baselines/reference/classMemberWithMissingIdentifier2.errors.txt
new file mode 100644
index 00000000000..b21e062e3b0
--- /dev/null
+++ b/tests/baselines/reference/classMemberWithMissingIdentifier2.errors.txt
@@ -0,0 +1,30 @@
+tests/cases/compiler/classMemberWithMissingIdentifier2.ts(2,11): error TS1146: Declaration expected.
+tests/cases/compiler/classMemberWithMissingIdentifier2.ts(2,12): error TS1005: '=' expected.
+tests/cases/compiler/classMemberWithMissingIdentifier2.ts(2,14): error TS2304: Cannot find name 'name'.
+tests/cases/compiler/classMemberWithMissingIdentifier2.ts(2,18): error TS1005: ']' expected.
+tests/cases/compiler/classMemberWithMissingIdentifier2.ts(2,19): error TS2304: Cannot find name 'string'.
+tests/cases/compiler/classMemberWithMissingIdentifier2.ts(2,25): error TS1005: ',' expected.
+tests/cases/compiler/classMemberWithMissingIdentifier2.ts(2,26): error TS1136: Property assignment expected.
+tests/cases/compiler/classMemberWithMissingIdentifier2.ts(2,27): error TS2304: Cannot find name 'VariableDeclaration'.
+
+
+==== tests/cases/compiler/classMemberWithMissingIdentifier2.ts (8 errors) ====
+    class C { 
+        public {[name:string]:VariableDeclaration};
+              
+!!! error TS1146: Declaration expected.
+               ~
+!!! error TS1005: '=' expected.
+                 ~~~~
+!!! error TS2304: Cannot find name 'name'.
+                     ~
+!!! error TS1005: ']' expected.
+                      ~~~~~~
+!!! error TS2304: Cannot find name 'string'.
+                            ~
+!!! error TS1005: ',' expected.
+                             ~
+!!! error TS1136: Property assignment expected.
+                              ~~~~~~~~~~~~~~~~~~~
+!!! error TS2304: Cannot find name 'VariableDeclaration'.
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/classMemberWithMissingIdentifier2.js b/tests/baselines/reference/classMemberWithMissingIdentifier2.js
new file mode 100644
index 00000000000..e8494755b22
--- /dev/null
+++ b/tests/baselines/reference/classMemberWithMissingIdentifier2.js
@@ -0,0 +1,13 @@
+//// [classMemberWithMissingIdentifier2.ts]
+class C { 
+    public {[name:string]:VariableDeclaration};
+}
+
+//// [classMemberWithMissingIdentifier2.js]
+var C = (function () {
+    function C() {
+        this. = (_a = {}, _a[name] = string, _a.VariableDeclaration = VariableDeclaration, _a);
+        var _a;
+    }
+    return C;
+})();
diff --git a/tests/baselines/reference/classOrder2.js b/tests/baselines/reference/classOrder2.js
index 8eed39bddeb..fd3fee2e037 100644
--- a/tests/baselines/reference/classOrder2.js
+++ b/tests/baselines/reference/classOrder2.js
@@ -23,8 +23,7 @@ a.foo();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function (_super) {
     __extends(A, _super);
diff --git a/tests/baselines/reference/classOrderBug.js b/tests/baselines/reference/classOrderBug.js
index ae50152d608..bc3f0e739c4 100644
--- a/tests/baselines/reference/classOrderBug.js
+++ b/tests/baselines/reference/classOrderBug.js
@@ -19,8 +19,7 @@ class foo extends baz {}
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var bar = (function () {
     function bar() {
diff --git a/tests/baselines/reference/classSideInheritance1.js b/tests/baselines/reference/classSideInheritance1.js
index 66cbc0c25c7..6d217149b83 100644
--- a/tests/baselines/reference/classSideInheritance1.js
+++ b/tests/baselines/reference/classSideInheritance1.js
@@ -19,8 +19,7 @@ C2.bar(); // valid
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/classSideInheritance2.js b/tests/baselines/reference/classSideInheritance2.js
index e09301fe85f..fb6f0d8cbb9 100644
--- a/tests/baselines/reference/classSideInheritance2.js
+++ b/tests/baselines/reference/classSideInheritance2.js
@@ -24,8 +24,7 @@ class TextBase implements IText {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var SubText = (function (_super) {
     __extends(SubText, _super);
diff --git a/tests/baselines/reference/classSideInheritance3.js b/tests/baselines/reference/classSideInheritance3.js
index a69b6ff0345..0891a7c9e74 100644
--- a/tests/baselines/reference/classSideInheritance3.js
+++ b/tests/baselines/reference/classSideInheritance3.js
@@ -22,8 +22,7 @@ var r3: typeof A = C; // ok
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A(x) {
diff --git a/tests/baselines/reference/classUpdateTests.js b/tests/baselines/reference/classUpdateTests.js
index 90149d88d9d..95db2680a1c 100644
--- a/tests/baselines/reference/classUpdateTests.js
+++ b/tests/baselines/reference/classUpdateTests.js
@@ -117,8 +117,7 @@ class R {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 //
 // test codegen for instance properties
diff --git a/tests/baselines/reference/classWithBaseClassButNoConstructor.js b/tests/baselines/reference/classWithBaseClassButNoConstructor.js
index f1a10b317a1..44e5d39c376 100644
--- a/tests/baselines/reference/classWithBaseClassButNoConstructor.js
+++ b/tests/baselines/reference/classWithBaseClassButNoConstructor.js
@@ -44,8 +44,7 @@ var d6 = new D(1); // ok
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(x) {
diff --git a/tests/baselines/reference/classWithConstructors.js b/tests/baselines/reference/classWithConstructors.js
index 467738e0966..a36db6ee745 100644
--- a/tests/baselines/reference/classWithConstructors.js
+++ b/tests/baselines/reference/classWithConstructors.js
@@ -53,8 +53,7 @@ module Generics {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var NonGeneric;
 (function (NonGeneric) {
diff --git a/tests/baselines/reference/classWithProtectedProperty.js b/tests/baselines/reference/classWithProtectedProperty.js
index 7d86e1c7229..ec8a203d200 100644
--- a/tests/baselines/reference/classWithProtectedProperty.js
+++ b/tests/baselines/reference/classWithProtectedProperty.js
@@ -32,8 +32,7 @@ class D extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/classWithStaticMembers.js b/tests/baselines/reference/classWithStaticMembers.js
index edad6c22c70..34928c37abd 100644
--- a/tests/baselines/reference/classWithStaticMembers.js
+++ b/tests/baselines/reference/classWithStaticMembers.js
@@ -23,8 +23,7 @@ var r3 = r.foo;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C(a, b) {
diff --git a/tests/baselines/reference/classdecl.js b/tests/baselines/reference/classdecl.js
index 127e0e9f32b..2af85da5b57 100644
--- a/tests/baselines/reference/classdecl.js
+++ b/tests/baselines/reference/classdecl.js
@@ -97,8 +97,7 @@ class e {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a(ns) {
diff --git a/tests/baselines/reference/clodulesDerivedClasses.js b/tests/baselines/reference/clodulesDerivedClasses.js
index c37b9f0e96a..652b3f7bac6 100644
--- a/tests/baselines/reference/clodulesDerivedClasses.js
+++ b/tests/baselines/reference/clodulesDerivedClasses.js
@@ -26,8 +26,7 @@ module Path.Utils {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Shape = (function () {
     function Shape() {
diff --git a/tests/baselines/reference/collisionSuperAndLocalFunctionInAccessors.js b/tests/baselines/reference/collisionSuperAndLocalFunctionInAccessors.js
index a58f4aa9f94..731f3d4f064 100644
--- a/tests/baselines/reference/collisionSuperAndLocalFunctionInAccessors.js
+++ b/tests/baselines/reference/collisionSuperAndLocalFunctionInAccessors.js
@@ -43,8 +43,7 @@ class c extends Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function _super() {
 }
diff --git a/tests/baselines/reference/collisionSuperAndLocalFunctionInConstructor.js b/tests/baselines/reference/collisionSuperAndLocalFunctionInConstructor.js
index b89a8753acd..06acaa0e02a 100644
--- a/tests/baselines/reference/collisionSuperAndLocalFunctionInConstructor.js
+++ b/tests/baselines/reference/collisionSuperAndLocalFunctionInConstructor.js
@@ -28,8 +28,7 @@ class c extends Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function _super() {
 }
diff --git a/tests/baselines/reference/collisionSuperAndLocalFunctionInMethod.js b/tests/baselines/reference/collisionSuperAndLocalFunctionInMethod.js
index efa9c1d9f03..6702ba8ac3d 100644
--- a/tests/baselines/reference/collisionSuperAndLocalFunctionInMethod.js
+++ b/tests/baselines/reference/collisionSuperAndLocalFunctionInMethod.js
@@ -32,8 +32,7 @@ class c extends Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function _super() {
 }
diff --git a/tests/baselines/reference/collisionSuperAndLocalFunctionInProperty.js b/tests/baselines/reference/collisionSuperAndLocalFunctionInProperty.js
index 228b7243d4f..8d13eed617b 100644
--- a/tests/baselines/reference/collisionSuperAndLocalFunctionInProperty.js
+++ b/tests/baselines/reference/collisionSuperAndLocalFunctionInProperty.js
@@ -22,8 +22,7 @@ class b extends Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function _super() {
 }
diff --git a/tests/baselines/reference/collisionSuperAndLocalVarInAccessors.js b/tests/baselines/reference/collisionSuperAndLocalVarInAccessors.js
index d2392f4df38..12685727795 100644
--- a/tests/baselines/reference/collisionSuperAndLocalVarInAccessors.js
+++ b/tests/baselines/reference/collisionSuperAndLocalVarInAccessors.js
@@ -36,8 +36,7 @@ class c extends Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var _super = 10; // No Error
 var Foo = (function () {
diff --git a/tests/baselines/reference/collisionSuperAndLocalVarInConstructor.js b/tests/baselines/reference/collisionSuperAndLocalVarInConstructor.js
index dc3210c1f8e..6f543492898 100644
--- a/tests/baselines/reference/collisionSuperAndLocalVarInConstructor.js
+++ b/tests/baselines/reference/collisionSuperAndLocalVarInConstructor.js
@@ -24,8 +24,7 @@ class c extends Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var _super = 10; // No Error
 var Foo = (function () {
diff --git a/tests/baselines/reference/collisionSuperAndLocalVarInMethod.js b/tests/baselines/reference/collisionSuperAndLocalVarInMethod.js
index 7a6ee0c45c5..373ee270014 100644
--- a/tests/baselines/reference/collisionSuperAndLocalVarInMethod.js
+++ b/tests/baselines/reference/collisionSuperAndLocalVarInMethod.js
@@ -22,8 +22,7 @@ class c extends Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var _super = 10; // No Error
 var Foo = (function () {
diff --git a/tests/baselines/reference/collisionSuperAndLocalVarInProperty.js b/tests/baselines/reference/collisionSuperAndLocalVarInProperty.js
index f678c7cf6ca..7ba9b407858 100644
--- a/tests/baselines/reference/collisionSuperAndLocalVarInProperty.js
+++ b/tests/baselines/reference/collisionSuperAndLocalVarInProperty.js
@@ -21,8 +21,7 @@ class b extends Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var _super = 10; // No Error
 var Foo = (function () {
diff --git a/tests/baselines/reference/collisionSuperAndNameResolution.js b/tests/baselines/reference/collisionSuperAndNameResolution.js
index 540a2b659d9..5cddcc01845 100644
--- a/tests/baselines/reference/collisionSuperAndNameResolution.js
+++ b/tests/baselines/reference/collisionSuperAndNameResolution.js
@@ -15,8 +15,7 @@ class Foo extends base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var console;
 var _super = 10; // No error
diff --git a/tests/baselines/reference/collisionSuperAndParameter.js b/tests/baselines/reference/collisionSuperAndParameter.js
index ac8947e00d3..965887d6d1b 100644
--- a/tests/baselines/reference/collisionSuperAndParameter.js
+++ b/tests/baselines/reference/collisionSuperAndParameter.js
@@ -66,8 +66,7 @@ class Foo4 extends Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/collisionSuperAndParameter1.js b/tests/baselines/reference/collisionSuperAndParameter1.js
index b072667396d..f6d1f23947d 100644
--- a/tests/baselines/reference/collisionSuperAndParameter1.js
+++ b/tests/baselines/reference/collisionSuperAndParameter1.js
@@ -13,8 +13,7 @@ class Foo2 extends Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/collisionSuperAndPropertyNameAsConstuctorParameter.js b/tests/baselines/reference/collisionSuperAndPropertyNameAsConstuctorParameter.js
index e96ae7d8928..f54bbef28a8 100644
--- a/tests/baselines/reference/collisionSuperAndPropertyNameAsConstuctorParameter.js
+++ b/tests/baselines/reference/collisionSuperAndPropertyNameAsConstuctorParameter.js
@@ -34,8 +34,7 @@ class b4 extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/collisionThisExpressionAndLocalVarWithSuperExperssion.js b/tests/baselines/reference/collisionThisExpressionAndLocalVarWithSuperExperssion.js
index dbf36111dfb..eb2ddd825fb 100644
--- a/tests/baselines/reference/collisionThisExpressionAndLocalVarWithSuperExperssion.js
+++ b/tests/baselines/reference/collisionThisExpressionAndLocalVarWithSuperExperssion.js
@@ -22,8 +22,7 @@ class b2 extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/commentsInheritance.js b/tests/baselines/reference/commentsInheritance.js
index 4fe5a30cb8b..33726436189 100644
--- a/tests/baselines/reference/commentsInheritance.js
+++ b/tests/baselines/reference/commentsInheritance.js
@@ -155,8 +155,7 @@ i2_i = i3_i;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var c1 = (function () {
     function c1() {
diff --git a/tests/baselines/reference/comparisonOperatorWithIdenticalObjects.js b/tests/baselines/reference/comparisonOperatorWithIdenticalObjects.js
index aebb486a1b5..d59ec764680 100644
--- a/tests/baselines/reference/comparisonOperatorWithIdenticalObjects.js
+++ b/tests/baselines/reference/comparisonOperatorWithIdenticalObjects.js
@@ -198,8 +198,7 @@ var r8b7 = b6 !== a6;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A1 = (function () {
     function A1() {
diff --git a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnCallSignature.js b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnCallSignature.js
index 3d7e96be633..4bbc7675a31 100644
--- a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnCallSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnCallSignature.js
@@ -172,8 +172,7 @@ var r8b7 = b7 !== a7;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnConstructorSignature.js b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnConstructorSignature.js
index 097246f183b..397c7e9d8e4 100644
--- a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnConstructorSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnConstructorSignature.js
@@ -172,8 +172,7 @@ var r8b7 = b7 !== a7;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.js b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.js
index 6bb3cddc8a7..9f3c037538d 100644
--- a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.js
@@ -115,8 +115,7 @@ var r8b4 = b4 !== a4;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnInstantiatedCallSignature.js b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnInstantiatedCallSignature.js
index dee8fb5ed5a..68ebcb9d596 100644
--- a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnInstantiatedCallSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnInstantiatedCallSignature.js
@@ -153,8 +153,7 @@ var r8b6 = b6 !== a6;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnInstantiatedConstructorSignature.js b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnInstantiatedConstructorSignature.js
index bc7db12ebf2..60177f0ea22 100644
--- a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnInstantiatedConstructorSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnInstantiatedConstructorSignature.js
@@ -153,8 +153,7 @@ var r8b6 = b6 !== a6;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnCallSignature.js b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnCallSignature.js
index a35ece1b617..27d1b68c85d 100644
--- a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnCallSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnCallSignature.js
@@ -263,8 +263,7 @@ var r8b11 = b11 !== a11;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnConstructorSignature.js b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnConstructorSignature.js
index 8ade79daa20..5a98e12b001 100644
--- a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnConstructorSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnConstructorSignature.js
@@ -225,8 +225,7 @@ var r8b9 = b9 !== a9;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnIndexSignature.js b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnIndexSignature.js
index 080c7990c04..24069615e0a 100644
--- a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnIndexSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnIndexSignature.js
@@ -111,8 +111,7 @@ var r8b1 = b4 !== a4;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedCallSignature.js b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedCallSignature.js
index f01b18496d5..f0dac057ca3 100644
--- a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedCallSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedCallSignature.js
@@ -168,8 +168,7 @@ var r8b6 = b6 !== a6;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedConstructorSignature.js b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedConstructorSignature.js
index bd4525e5c7b..eaf1aca728d 100644
--- a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedConstructorSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedConstructorSignature.js
@@ -168,8 +168,7 @@ var r8b6 = b6 !== a6;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnProperty.js b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnProperty.js
index cbd31f56b30..822d4b7520a 100644
--- a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnProperty.js
+++ b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnProperty.js
@@ -82,8 +82,7 @@ var rh4 = b2 !== a2;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/complexClassRelationships.js b/tests/baselines/reference/complexClassRelationships.js
index 2d750b77f71..ca2b31a805c 100644
--- a/tests/baselines/reference/complexClassRelationships.js
+++ b/tests/baselines/reference/complexClassRelationships.js
@@ -51,8 +51,7 @@ class FooBase {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // There should be no errors in this file
 var Derived = (function (_super) {
diff --git a/tests/baselines/reference/complicatedGenericRecursiveBaseClassReference.js b/tests/baselines/reference/complicatedGenericRecursiveBaseClassReference.js
index 920172b206d..71c1cee164f 100644
--- a/tests/baselines/reference/complicatedGenericRecursiveBaseClassReference.js
+++ b/tests/baselines/reference/complicatedGenericRecursiveBaseClassReference.js
@@ -9,8 +9,7 @@ class S18<B, A, C> extends S18<A[], { S19: A; (): A }[], C[]>
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var S18 = (function (_super) {
     __extends(S18, _super);
diff --git a/tests/baselines/reference/compoundAssignmentLHSIsValue.js b/tests/baselines/reference/compoundAssignmentLHSIsValue.js
index 4c5c050dc83..833c1e1ea7c 100644
--- a/tests/baselines/reference/compoundAssignmentLHSIsValue.js
+++ b/tests/baselines/reference/compoundAssignmentLHSIsValue.js
@@ -126,8 +126,7 @@ foo() += value;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // expected error for all the LHS of compound assignments (arithmetic and addition)
 var value;
diff --git a/tests/baselines/reference/computedPropertyNames24_ES5.js b/tests/baselines/reference/computedPropertyNames24_ES5.js
index e433383eb5c..5a4b79cf44a 100644
--- a/tests/baselines/reference/computedPropertyNames24_ES5.js
+++ b/tests/baselines/reference/computedPropertyNames24_ES5.js
@@ -12,8 +12,7 @@ class C extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/computedPropertyNames25_ES5.js b/tests/baselines/reference/computedPropertyNames25_ES5.js
index eca2485ab7d..832fad174d8 100644
--- a/tests/baselines/reference/computedPropertyNames25_ES5.js
+++ b/tests/baselines/reference/computedPropertyNames25_ES5.js
@@ -17,8 +17,7 @@ class C extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/computedPropertyNames26_ES5.js b/tests/baselines/reference/computedPropertyNames26_ES5.js
index 0e3b6c126bc..09a95419480 100644
--- a/tests/baselines/reference/computedPropertyNames26_ES5.js
+++ b/tests/baselines/reference/computedPropertyNames26_ES5.js
@@ -14,8 +14,7 @@ class C extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/computedPropertyNames27_ES5.js b/tests/baselines/reference/computedPropertyNames27_ES5.js
index 12f02fbefa9..53e2c2988c8 100644
--- a/tests/baselines/reference/computedPropertyNames27_ES5.js
+++ b/tests/baselines/reference/computedPropertyNames27_ES5.js
@@ -9,8 +9,7 @@ class C extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/computedPropertyNames28_ES5.js b/tests/baselines/reference/computedPropertyNames28_ES5.js
index b2be5f120a5..be79f22c2da 100644
--- a/tests/baselines/reference/computedPropertyNames28_ES5.js
+++ b/tests/baselines/reference/computedPropertyNames28_ES5.js
@@ -14,8 +14,7 @@ class C extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/computedPropertyNames30_ES5.js b/tests/baselines/reference/computedPropertyNames30_ES5.js
index 6bbca3da056..de60b5daf53 100644
--- a/tests/baselines/reference/computedPropertyNames30_ES5.js
+++ b/tests/baselines/reference/computedPropertyNames30_ES5.js
@@ -19,8 +19,7 @@ class C extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/computedPropertyNames31_ES5.js b/tests/baselines/reference/computedPropertyNames31_ES5.js
index fb7d651364b..f8e34603305 100644
--- a/tests/baselines/reference/computedPropertyNames31_ES5.js
+++ b/tests/baselines/reference/computedPropertyNames31_ES5.js
@@ -19,8 +19,7 @@ class C extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/computedPropertyNames43_ES5.js b/tests/baselines/reference/computedPropertyNames43_ES5.js
index e51df61a8c1..c3b7f6a71d0 100644
--- a/tests/baselines/reference/computedPropertyNames43_ES5.js
+++ b/tests/baselines/reference/computedPropertyNames43_ES5.js
@@ -16,8 +16,7 @@ class D extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/computedPropertyNames44_ES5.js b/tests/baselines/reference/computedPropertyNames44_ES5.js
index 5efc5a11496..1186f0caef7 100644
--- a/tests/baselines/reference/computedPropertyNames44_ES5.js
+++ b/tests/baselines/reference/computedPropertyNames44_ES5.js
@@ -15,8 +15,7 @@ class D extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/computedPropertyNames45_ES5.js b/tests/baselines/reference/computedPropertyNames45_ES5.js
index d7fb6f35407..ce948e58208 100644
--- a/tests/baselines/reference/computedPropertyNames45_ES5.js
+++ b/tests/baselines/reference/computedPropertyNames45_ES5.js
@@ -16,8 +16,7 @@ class D extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/conditionalOperatorWithIdenticalBCT.js b/tests/baselines/reference/conditionalOperatorWithIdenticalBCT.js
index 18c09a500a6..a493a5cfab0 100644
--- a/tests/baselines/reference/conditionalOperatorWithIdenticalBCT.js
+++ b/tests/baselines/reference/conditionalOperatorWithIdenticalBCT.js
@@ -51,8 +51,7 @@ var result11: any = true ? 1 : 'string';
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 //Cond ? Expr1 : Expr2,  Expr1 and Expr2 have identical best common type
 var X = (function () {
diff --git a/tests/baselines/reference/conditionalOperatorWithoutIdenticalBCT.js b/tests/baselines/reference/conditionalOperatorWithoutIdenticalBCT.js
index 62b887d7e60..3d75eb0507a 100644
--- a/tests/baselines/reference/conditionalOperatorWithoutIdenticalBCT.js
+++ b/tests/baselines/reference/conditionalOperatorWithoutIdenticalBCT.js
@@ -27,8 +27,7 @@ var result61: (t: X) => number| string = true ? (m) => m.propertyX1 : (n) => n.p
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 //Cond ? Expr1 : Expr2,  Expr1 and Expr2 have no identical best common type
 var X = (function () {
diff --git a/tests/baselines/reference/constantOverloadFunction.js b/tests/baselines/reference/constantOverloadFunction.js
index aa89c619e7e..45c0fe9ff0a 100644
--- a/tests/baselines/reference/constantOverloadFunction.js
+++ b/tests/baselines/reference/constantOverloadFunction.js
@@ -17,8 +17,7 @@ function foo(tagName: any): Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/constantOverloadFunctionNoSubtypeError.js b/tests/baselines/reference/constantOverloadFunctionNoSubtypeError.js
index 529f888bfc9..946f8196372 100644
--- a/tests/baselines/reference/constantOverloadFunctionNoSubtypeError.js
+++ b/tests/baselines/reference/constantOverloadFunctionNoSubtypeError.js
@@ -18,8 +18,7 @@ function foo(tagName: any): Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/constraintCheckInGenericBaseTypeReference.js b/tests/baselines/reference/constraintCheckInGenericBaseTypeReference.js
index 22b77ba6816..9cf9d71f7a2 100644
--- a/tests/baselines/reference/constraintCheckInGenericBaseTypeReference.js
+++ b/tests/baselines/reference/constraintCheckInGenericBaseTypeReference.js
@@ -23,8 +23,7 @@ class Container {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // No errors
 var Constraint = (function () {
diff --git a/tests/baselines/reference/constructSignatureAssignabilityInInheritance2.js b/tests/baselines/reference/constructSignatureAssignabilityInInheritance2.js
index c1c10ead1e3..38b7b7fc194 100644
--- a/tests/baselines/reference/constructSignatureAssignabilityInInheritance2.js
+++ b/tests/baselines/reference/constructSignatureAssignabilityInInheritance2.js
@@ -74,8 +74,7 @@ interface I extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/constructSignatureAssignabilityInInheritance3.js b/tests/baselines/reference/constructSignatureAssignabilityInInheritance3.js
index 12907c6d032..7d07c1a1712 100644
--- a/tests/baselines/reference/constructSignatureAssignabilityInInheritance3.js
+++ b/tests/baselines/reference/constructSignatureAssignabilityInInheritance3.js
@@ -117,8 +117,7 @@ module Errors {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Errors;
 (function (Errors) {
diff --git a/tests/baselines/reference/constructSignatureAssignabilityInInheritance4.js b/tests/baselines/reference/constructSignatureAssignabilityInInheritance4.js
index ef03802a17e..ba341eec61f 100644
--- a/tests/baselines/reference/constructSignatureAssignabilityInInheritance4.js
+++ b/tests/baselines/reference/constructSignatureAssignabilityInInheritance4.js
@@ -64,8 +64,7 @@ interface I extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/constructSignatureAssignabilityInInheritance5.js b/tests/baselines/reference/constructSignatureAssignabilityInInheritance5.js
index 9964a3464a1..304b5cafd66 100644
--- a/tests/baselines/reference/constructSignatureAssignabilityInInheritance5.js
+++ b/tests/baselines/reference/constructSignatureAssignabilityInInheritance5.js
@@ -54,8 +54,7 @@ interface I extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/constructSignatureAssignabilityInInheritance6.js b/tests/baselines/reference/constructSignatureAssignabilityInInheritance6.js
index 4cf9b7d71f5..99c885f9716 100644
--- a/tests/baselines/reference/constructSignatureAssignabilityInInheritance6.js
+++ b/tests/baselines/reference/constructSignatureAssignabilityInInheritance6.js
@@ -57,8 +57,7 @@ interface I9<T> extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/constructorArgs.js b/tests/baselines/reference/constructorArgs.js
index 93a47178d52..6fc3511b70e 100644
--- a/tests/baselines/reference/constructorArgs.js
+++ b/tests/baselines/reference/constructorArgs.js
@@ -19,8 +19,7 @@ class Sub extends Super {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Super = (function () {
     function Super(value) {
diff --git a/tests/baselines/reference/constructorFunctionTypeIsAssignableToBaseType.js b/tests/baselines/reference/constructorFunctionTypeIsAssignableToBaseType.js
index 9c92f31ce97..305b3e54ead 100644
--- a/tests/baselines/reference/constructorFunctionTypeIsAssignableToBaseType.js
+++ b/tests/baselines/reference/constructorFunctionTypeIsAssignableToBaseType.js
@@ -23,8 +23,7 @@ class Derived2 extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/constructorFunctionTypeIsAssignableToBaseType2.js b/tests/baselines/reference/constructorFunctionTypeIsAssignableToBaseType2.js
index 61cf399f613..b2bf377f0cc 100644
--- a/tests/baselines/reference/constructorFunctionTypeIsAssignableToBaseType2.js
+++ b/tests/baselines/reference/constructorFunctionTypeIsAssignableToBaseType2.js
@@ -37,8 +37,7 @@ class Derived2 extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(x) {
diff --git a/tests/baselines/reference/constructorHasPrototypeProperty.js b/tests/baselines/reference/constructorHasPrototypeProperty.js
index 47020120f9f..a1bdee8e7d4 100644
--- a/tests/baselines/reference/constructorHasPrototypeProperty.js
+++ b/tests/baselines/reference/constructorHasPrototypeProperty.js
@@ -35,8 +35,7 @@ module Generic {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var NonGeneric;
 (function (NonGeneric) {
diff --git a/tests/baselines/reference/constructorOverloads2.js b/tests/baselines/reference/constructorOverloads2.js
index 16da3f0fa0a..d95477d84f6 100644
--- a/tests/baselines/reference/constructorOverloads2.js
+++ b/tests/baselines/reference/constructorOverloads2.js
@@ -29,8 +29,7 @@ f1.bar1();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var FooBase = (function () {
     function FooBase(x) {
diff --git a/tests/baselines/reference/constructorOverloads3.js b/tests/baselines/reference/constructorOverloads3.js
index f4299466aa1..c7e4e411319 100644
--- a/tests/baselines/reference/constructorOverloads3.js
+++ b/tests/baselines/reference/constructorOverloads3.js
@@ -26,8 +26,7 @@ f1.bar1();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function (_super) {
     __extends(Foo, _super);
diff --git a/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.js b/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.js
index 01a1880ffd5..5a61d4d5d7e 100644
--- a/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.js
+++ b/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.js
@@ -283,8 +283,7 @@ TypeScriptAllInOne.Program.Main();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var fs = module;
 ("fs");
diff --git a/tests/baselines/reference/contextualTypingArrayOfLambdas.js b/tests/baselines/reference/contextualTypingArrayOfLambdas.js
index e24ae90176c..59da607079b 100644
--- a/tests/baselines/reference/contextualTypingArrayOfLambdas.js
+++ b/tests/baselines/reference/contextualTypingArrayOfLambdas.js
@@ -18,8 +18,7 @@ var xs = [(x: A) => { }, (x: B) => { }, (x: C) => { }];
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/contextualTypingOfConditionalExpression.js b/tests/baselines/reference/contextualTypingOfConditionalExpression.js
index 72c15455e8e..a0f8ea0a4cf 100644
--- a/tests/baselines/reference/contextualTypingOfConditionalExpression.js
+++ b/tests/baselines/reference/contextualTypingOfConditionalExpression.js
@@ -18,8 +18,7 @@ var x2: (a: A) => void = true ? (a) => a.foo : (b) => b.foo;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var x = true ? function (a) { return a.toExponential(); } : function (b) { return b.toFixed(); };
 var A = (function () {
diff --git a/tests/baselines/reference/contextualTypingOfConditionalExpression2.js b/tests/baselines/reference/contextualTypingOfConditionalExpression2.js
index 4e6b95a6857..2833ed37d4b 100644
--- a/tests/baselines/reference/contextualTypingOfConditionalExpression2.js
+++ b/tests/baselines/reference/contextualTypingOfConditionalExpression2.js
@@ -16,8 +16,7 @@ var x2: (a: A) => void = true ? (a: C) => a.foo : (b: number) => { };
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/crashInsourcePropertyIsRelatableToTargetProperty.js b/tests/baselines/reference/crashInsourcePropertyIsRelatableToTargetProperty.js
index 17c9ac649d8..332f4897fc7 100644
--- a/tests/baselines/reference/crashInsourcePropertyIsRelatableToTargetProperty.js
+++ b/tests/baselines/reference/crashInsourcePropertyIsRelatableToTargetProperty.js
@@ -14,8 +14,7 @@ var a: D = foo("hi", []);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/declFileForFunctionTypeAsTypeParameter.js b/tests/baselines/reference/declFileForFunctionTypeAsTypeParameter.js
index 134bacd6053..0f13824fc45 100644
--- a/tests/baselines/reference/declFileForFunctionTypeAsTypeParameter.js
+++ b/tests/baselines/reference/declFileForFunctionTypeAsTypeParameter.js
@@ -13,8 +13,7 @@ interface I extends X<() => number> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var X = (function () {
     function X() {
diff --git a/tests/baselines/reference/declFileGenericClassWithGenericExtendedClass.js b/tests/baselines/reference/declFileGenericClassWithGenericExtendedClass.js
index 23630ba5218..caaba28859a 100644
--- a/tests/baselines/reference/declFileGenericClassWithGenericExtendedClass.js
+++ b/tests/baselines/reference/declFileGenericClassWithGenericExtendedClass.js
@@ -16,8 +16,7 @@ class Baz implements IBar<Baz> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/declFileGenericType.js b/tests/baselines/reference/declFileGenericType.js
index dfbe147a78d..b67bacebb1a 100644
--- a/tests/baselines/reference/declFileGenericType.js
+++ b/tests/baselines/reference/declFileGenericType.js
@@ -43,8 +43,7 @@ export var j = C.F6;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C;
 (function (C) {
diff --git a/tests/baselines/reference/declFileGenericType2.js b/tests/baselines/reference/declFileGenericType2.js
index 03649af4ba6..416e0f6737c 100644
--- a/tests/baselines/reference/declFileGenericType2.js
+++ b/tests/baselines/reference/declFileGenericType2.js
@@ -46,8 +46,7 @@ module templa.dom.mvc.composite {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // Module
 var templa;
diff --git a/tests/baselines/reference/declFileWithClassNameConflictingWithClassReferredByExtendsClause.js b/tests/baselines/reference/declFileWithClassNameConflictingWithClassReferredByExtendsClause.js
index 8881122839e..e21c28138a2 100644
--- a/tests/baselines/reference/declFileWithClassNameConflictingWithClassReferredByExtendsClause.js
+++ b/tests/baselines/reference/declFileWithClassNameConflictingWithClassReferredByExtendsClause.js
@@ -24,8 +24,7 @@ module X.Y.base.Z {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var X;
 (function (X) {
diff --git a/tests/baselines/reference/declFileWithExtendsClauseThatHasItsContainerNameConflict.js b/tests/baselines/reference/declFileWithExtendsClauseThatHasItsContainerNameConflict.js
index c06461e89fc..587b8ff1e27 100644
--- a/tests/baselines/reference/declFileWithExtendsClauseThatHasItsContainerNameConflict.js
+++ b/tests/baselines/reference/declFileWithExtendsClauseThatHasItsContainerNameConflict.js
@@ -22,8 +22,7 @@ module A.B.C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A;
 (function (A) {
diff --git a/tests/baselines/reference/declarationEmit_nameConflicts3.js b/tests/baselines/reference/declarationEmit_nameConflicts3.js
index ee21d9a408d..07299132bd4 100644
--- a/tests/baselines/reference/declarationEmit_nameConflicts3.js
+++ b/tests/baselines/reference/declarationEmit_nameConflicts3.js
@@ -30,8 +30,7 @@ module M.P {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/declarationEmit_protectedMembers.js b/tests/baselines/reference/declarationEmit_protectedMembers.js
index faa1dc298e1..536f4f4aff7 100644
--- a/tests/baselines/reference/declarationEmit_protectedMembers.js
+++ b/tests/baselines/reference/declarationEmit_protectedMembers.js
@@ -54,8 +54,7 @@ class C4 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // Class with protected members
 var C1 = (function () {
diff --git a/tests/baselines/reference/declareDottedExtend.js b/tests/baselines/reference/declareDottedExtend.js
index 2579a5557fc..030e5048ef7 100644
--- a/tests/baselines/reference/declareDottedExtend.js
+++ b/tests/baselines/reference/declareDottedExtend.js
@@ -15,8 +15,7 @@ class E extends A.B.C{ }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var ab = A.B;
 var D = (function (_super) {
diff --git a/tests/baselines/reference/decoratorOnClassMethod12.js b/tests/baselines/reference/decoratorOnClassMethod12.js
index aa938eaaaf4..05c4f285291 100644
--- a/tests/baselines/reference/decoratorOnClassMethod12.js
+++ b/tests/baselines/reference/decoratorOnClassMethod12.js
@@ -13,8 +13,7 @@ module M {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
     if (typeof Reflect === "object" && typeof Reflect.decorate === "function") return Reflect.decorate(decorators, target, key, desc);
diff --git a/tests/baselines/reference/derivedClassConstructorWithoutSuperCall.js b/tests/baselines/reference/derivedClassConstructorWithoutSuperCall.js
index 37dc2db870b..b9090176add 100644
--- a/tests/baselines/reference/derivedClassConstructorWithoutSuperCall.js
+++ b/tests/baselines/reference/derivedClassConstructorWithoutSuperCall.js
@@ -37,8 +37,7 @@ class Derived4<T> extends Base2<T> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedClassFunctionOverridesBaseClassAccessor.js b/tests/baselines/reference/derivedClassFunctionOverridesBaseClassAccessor.js
index eaf7dfd5698..64da47e68e0 100644
--- a/tests/baselines/reference/derivedClassFunctionOverridesBaseClassAccessor.js
+++ b/tests/baselines/reference/derivedClassFunctionOverridesBaseClassAccessor.js
@@ -18,8 +18,7 @@ class Derived extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedClassIncludesInheritedMembers.js b/tests/baselines/reference/derivedClassIncludesInheritedMembers.js
index b83255ccf93..0538ba9b54a 100644
--- a/tests/baselines/reference/derivedClassIncludesInheritedMembers.js
+++ b/tests/baselines/reference/derivedClassIncludesInheritedMembers.js
@@ -44,8 +44,7 @@ var r8 = d2[1];
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(x) {
diff --git a/tests/baselines/reference/derivedClassOverridesIndexersWithAssignmentCompatibility.js b/tests/baselines/reference/derivedClassOverridesIndexersWithAssignmentCompatibility.js
index 1fe59d78044..a575c9bb183 100644
--- a/tests/baselines/reference/derivedClassOverridesIndexersWithAssignmentCompatibility.js
+++ b/tests/baselines/reference/derivedClassOverridesIndexersWithAssignmentCompatibility.js
@@ -21,8 +21,7 @@ class Derived2 extends Base2 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedClassOverridesPrivateFunction1.js b/tests/baselines/reference/derivedClassOverridesPrivateFunction1.js
index b9cd6df0338..7e11209b8fe 100644
--- a/tests/baselines/reference/derivedClassOverridesPrivateFunction1.js
+++ b/tests/baselines/reference/derivedClassOverridesPrivateFunction1.js
@@ -19,8 +19,7 @@ new DerivedClass();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var BaseClass = (function () {
     function BaseClass() {
diff --git a/tests/baselines/reference/derivedClassOverridesPrivates.js b/tests/baselines/reference/derivedClassOverridesPrivates.js
index 2cc8360a803..6662b5013d8 100644
--- a/tests/baselines/reference/derivedClassOverridesPrivates.js
+++ b/tests/baselines/reference/derivedClassOverridesPrivates.js
@@ -19,8 +19,7 @@ class Derived2 extends Base2 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedClassOverridesProtectedMembers.js b/tests/baselines/reference/derivedClassOverridesProtectedMembers.js
index 48ee6eded6c..21f2ce87880 100644
--- a/tests/baselines/reference/derivedClassOverridesProtectedMembers.js
+++ b/tests/baselines/reference/derivedClassOverridesProtectedMembers.js
@@ -40,8 +40,7 @@ class Derived extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var x;
 var y;
diff --git a/tests/baselines/reference/derivedClassOverridesProtectedMembers2.js b/tests/baselines/reference/derivedClassOverridesProtectedMembers2.js
index fca27b0de04..b5fe3e93af5 100644
--- a/tests/baselines/reference/derivedClassOverridesProtectedMembers2.js
+++ b/tests/baselines/reference/derivedClassOverridesProtectedMembers2.js
@@ -67,8 +67,7 @@ var r8 = d2[1];
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var x;
 var y;
diff --git a/tests/baselines/reference/derivedClassOverridesProtectedMembers3.js b/tests/baselines/reference/derivedClassOverridesProtectedMembers3.js
index 2a102d55eac..c4dc1d0e9d5 100644
--- a/tests/baselines/reference/derivedClassOverridesProtectedMembers3.js
+++ b/tests/baselines/reference/derivedClassOverridesProtectedMembers3.js
@@ -75,8 +75,7 @@ class Derived10 extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var x;
 var y;
diff --git a/tests/baselines/reference/derivedClassOverridesProtectedMembers4.js b/tests/baselines/reference/derivedClassOverridesProtectedMembers4.js
index 5145f3919a8..f25c3b792de 100644
--- a/tests/baselines/reference/derivedClassOverridesProtectedMembers4.js
+++ b/tests/baselines/reference/derivedClassOverridesProtectedMembers4.js
@@ -18,8 +18,7 @@ class Derived2 extends Derived1 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var x;
 var y;
diff --git a/tests/baselines/reference/derivedClassOverridesPublicMembers.js b/tests/baselines/reference/derivedClassOverridesPublicMembers.js
index 0529189e4c1..5125be4eeeb 100644
--- a/tests/baselines/reference/derivedClassOverridesPublicMembers.js
+++ b/tests/baselines/reference/derivedClassOverridesPublicMembers.js
@@ -66,8 +66,7 @@ var r8 = d2[1];
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var x;
 var y;
diff --git a/tests/baselines/reference/derivedClassOverridesWithoutSubtype.js b/tests/baselines/reference/derivedClassOverridesWithoutSubtype.js
index 5cb746bfdd3..9762c88035a 100644
--- a/tests/baselines/reference/derivedClassOverridesWithoutSubtype.js
+++ b/tests/baselines/reference/derivedClassOverridesWithoutSubtype.js
@@ -27,8 +27,7 @@ class Derived2 extends Base2 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedClassParameterProperties.js b/tests/baselines/reference/derivedClassParameterProperties.js
index dd5b206ecdd..55c0a312b71 100644
--- a/tests/baselines/reference/derivedClassParameterProperties.js
+++ b/tests/baselines/reference/derivedClassParameterProperties.js
@@ -99,8 +99,7 @@ class Derived10<T> extends Base2<T> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedClassSuperCallsInNonConstructorMembers.js b/tests/baselines/reference/derivedClassSuperCallsInNonConstructorMembers.js
index d2914cd6949..0c214d42fec 100644
--- a/tests/baselines/reference/derivedClassSuperCallsInNonConstructorMembers.js
+++ b/tests/baselines/reference/derivedClassSuperCallsInNonConstructorMembers.js
@@ -36,8 +36,7 @@ class Derived extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedClassSuperCallsWithThisArg.js b/tests/baselines/reference/derivedClassSuperCallsWithThisArg.js
index 7c7e9b40cec..a81a092fa54 100644
--- a/tests/baselines/reference/derivedClassSuperCallsWithThisArg.js
+++ b/tests/baselines/reference/derivedClassSuperCallsWithThisArg.js
@@ -32,8 +32,7 @@ class Derived4 extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(a) {
diff --git a/tests/baselines/reference/derivedClassTransitivity.js b/tests/baselines/reference/derivedClassTransitivity.js
index ad4f3e481a7..de7669a71b5 100644
--- a/tests/baselines/reference/derivedClassTransitivity.js
+++ b/tests/baselines/reference/derivedClassTransitivity.js
@@ -25,8 +25,7 @@ var r2 = e.foo('');
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/derivedClassTransitivity2.js b/tests/baselines/reference/derivedClassTransitivity2.js
index efeb25195ff..22e930ab7f9 100644
--- a/tests/baselines/reference/derivedClassTransitivity2.js
+++ b/tests/baselines/reference/derivedClassTransitivity2.js
@@ -25,8 +25,7 @@ var r2 = e.foo(1, '');
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/derivedClassTransitivity3.js b/tests/baselines/reference/derivedClassTransitivity3.js
index 8befbf18731..a1aa3a978eb 100644
--- a/tests/baselines/reference/derivedClassTransitivity3.js
+++ b/tests/baselines/reference/derivedClassTransitivity3.js
@@ -25,8 +25,7 @@ var r2 = e.foo('', 1);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/derivedClassTransitivity4.js b/tests/baselines/reference/derivedClassTransitivity4.js
index 546c7e4a849..a4d319707c7 100644
--- a/tests/baselines/reference/derivedClassTransitivity4.js
+++ b/tests/baselines/reference/derivedClassTransitivity4.js
@@ -25,8 +25,7 @@ var r2 = e.foo('');
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/derivedClassWithAny.js b/tests/baselines/reference/derivedClassWithAny.js
index 6f9ef484627..123853f3afd 100644
--- a/tests/baselines/reference/derivedClassWithAny.js
+++ b/tests/baselines/reference/derivedClassWithAny.js
@@ -63,8 +63,7 @@ var r = c.foo(); // e.foo would return string
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/derivedClassWithPrivateInstanceShadowingProtectedInstance.js b/tests/baselines/reference/derivedClassWithPrivateInstanceShadowingProtectedInstance.js
index bf8b1b51cd1..3454c60f881 100644
--- a/tests/baselines/reference/derivedClassWithPrivateInstanceShadowingProtectedInstance.js
+++ b/tests/baselines/reference/derivedClassWithPrivateInstanceShadowingProtectedInstance.js
@@ -26,8 +26,7 @@ class Derived extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedClassWithPrivateInstanceShadowingPublicInstance.js b/tests/baselines/reference/derivedClassWithPrivateInstanceShadowingPublicInstance.js
index 131c529f3bf..7de92c9cb2f 100644
--- a/tests/baselines/reference/derivedClassWithPrivateInstanceShadowingPublicInstance.js
+++ b/tests/baselines/reference/derivedClassWithPrivateInstanceShadowingPublicInstance.js
@@ -36,8 +36,7 @@ Derived.a = 2; // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedClassWithPrivateStaticShadowingProtectedStatic.js b/tests/baselines/reference/derivedClassWithPrivateStaticShadowingProtectedStatic.js
index d661eeadc06..36d2b7d2dc3 100644
--- a/tests/baselines/reference/derivedClassWithPrivateStaticShadowingProtectedStatic.js
+++ b/tests/baselines/reference/derivedClassWithPrivateStaticShadowingProtectedStatic.js
@@ -25,8 +25,7 @@ class Derived extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedClassWithPrivateStaticShadowingPublicStatic.js b/tests/baselines/reference/derivedClassWithPrivateStaticShadowingPublicStatic.js
index c3fc34b21c1..36080385b3b 100644
--- a/tests/baselines/reference/derivedClassWithPrivateStaticShadowingPublicStatic.js
+++ b/tests/baselines/reference/derivedClassWithPrivateStaticShadowingPublicStatic.js
@@ -37,8 +37,7 @@ Derived.a = 2; // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedClassWithoutExplicitConstructor.js b/tests/baselines/reference/derivedClassWithoutExplicitConstructor.js
index 16b9b110a5f..27a634ab2d9 100644
--- a/tests/baselines/reference/derivedClassWithoutExplicitConstructor.js
+++ b/tests/baselines/reference/derivedClassWithoutExplicitConstructor.js
@@ -29,8 +29,7 @@ var d2 = new D(new Date()); // ok
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(x) {
diff --git a/tests/baselines/reference/derivedClassWithoutExplicitConstructor2.js b/tests/baselines/reference/derivedClassWithoutExplicitConstructor2.js
index 6e413752f1d..82c5eec1d7d 100644
--- a/tests/baselines/reference/derivedClassWithoutExplicitConstructor2.js
+++ b/tests/baselines/reference/derivedClassWithoutExplicitConstructor2.js
@@ -37,8 +37,7 @@ var d4 = new D(new Date(), new Date(), new Date());
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(x) {
diff --git a/tests/baselines/reference/derivedClassWithoutExplicitConstructor3.js b/tests/baselines/reference/derivedClassWithoutExplicitConstructor3.js
index b72fdb1503d..4bfa7c81577 100644
--- a/tests/baselines/reference/derivedClassWithoutExplicitConstructor3.js
+++ b/tests/baselines/reference/derivedClassWithoutExplicitConstructor3.js
@@ -51,8 +51,7 @@ var d3 = new D2(new Date(), new Date()); // ok
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(x) {
diff --git a/tests/baselines/reference/derivedClasses.js b/tests/baselines/reference/derivedClasses.js
index 7221031cb8b..214c65bde6c 100644
--- a/tests/baselines/reference/derivedClasses.js
+++ b/tests/baselines/reference/derivedClasses.js
@@ -34,8 +34,7 @@ b.hue();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Red = (function (_super) {
     __extends(Red, _super);
diff --git a/tests/baselines/reference/derivedGenericClassWithAny.js b/tests/baselines/reference/derivedGenericClassWithAny.js
index b5bfbd5e5db..15835e78bd5 100644
--- a/tests/baselines/reference/derivedGenericClassWithAny.js
+++ b/tests/baselines/reference/derivedGenericClassWithAny.js
@@ -46,8 +46,7 @@ var r = c.foo(); // e.foo would return string
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/derivedTypeAccessesHiddenBaseCallViaSuperPropertyAccess.js b/tests/baselines/reference/derivedTypeAccessesHiddenBaseCallViaSuperPropertyAccess.js
index 564a51f2b13..0839b93971b 100644
--- a/tests/baselines/reference/derivedTypeAccessesHiddenBaseCallViaSuperPropertyAccess.js
+++ b/tests/baselines/reference/derivedTypeAccessesHiddenBaseCallViaSuperPropertyAccess.js
@@ -21,8 +21,7 @@ class Derived extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/derivedTypeDoesNotRequireExtendsClause.js b/tests/baselines/reference/derivedTypeDoesNotRequireExtendsClause.js
index f981a5e6e54..f00c32114cf 100644
--- a/tests/baselines/reference/derivedTypeDoesNotRequireExtendsClause.js
+++ b/tests/baselines/reference/derivedTypeDoesNotRequireExtendsClause.js
@@ -24,8 +24,7 @@ var r: Base[] = [d1, d2];
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/destructuringParameterDeclaration5.js b/tests/baselines/reference/destructuringParameterDeclaration5.js
index 7540302599c..38366ca67ba 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration5.js
+++ b/tests/baselines/reference/destructuringParameterDeclaration5.js
@@ -55,8 +55,7 @@ d3({ y: "world" });
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Class = (function () {
     function Class() {
diff --git a/tests/baselines/reference/emitThisInSuperMethodCall.js b/tests/baselines/reference/emitThisInSuperMethodCall.js
index 9224e156de9..f5cff5a8fa5 100644
--- a/tests/baselines/reference/emitThisInSuperMethodCall.js
+++ b/tests/baselines/reference/emitThisInSuperMethodCall.js
@@ -31,8 +31,7 @@ class RegisteredUser extends User {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var User = (function () {
     function User() {
diff --git a/tests/baselines/reference/errorForwardReferenceForwadingConstructor.js b/tests/baselines/reference/errorForwardReferenceForwadingConstructor.js
index f1a0d741a5c..0b30745fa15 100644
--- a/tests/baselines/reference/errorForwardReferenceForwadingConstructor.js
+++ b/tests/baselines/reference/errorForwardReferenceForwadingConstructor.js
@@ -15,8 +15,7 @@ class derived extends base { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function f() {
     var d1 = new derived();
diff --git a/tests/baselines/reference/errorSuperCalls.js b/tests/baselines/reference/errorSuperCalls.js
index bd692f35fa3..d2d4911c76a 100644
--- a/tests/baselines/reference/errorSuperCalls.js
+++ b/tests/baselines/reference/errorSuperCalls.js
@@ -78,8 +78,7 @@ class OtherDerived extends OtherBase {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 //super call in class constructor with no base type
 var NoBase = (function () {
diff --git a/tests/baselines/reference/errorSuperPropertyAccess.js b/tests/baselines/reference/errorSuperPropertyAccess.js
index abf077d2b82..57a574d8a06 100644
--- a/tests/baselines/reference/errorSuperPropertyAccess.js
+++ b/tests/baselines/reference/errorSuperPropertyAccess.js
@@ -132,8 +132,7 @@ var obj = { n: super.wat, p: super.foo() };
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 //super property access in constructor of class with no base type
 //super property access in instance member function of class with no base type
diff --git a/tests/baselines/reference/errorsInGenericTypeReference.js b/tests/baselines/reference/errorsInGenericTypeReference.js
index 0ba69b601ae..42c7456be60 100644
--- a/tests/baselines/reference/errorsInGenericTypeReference.js
+++ b/tests/baselines/reference/errorsInGenericTypeReference.js
@@ -76,8 +76,7 @@ interface testInterface2 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/es6ClassSuperCodegenBug.js b/tests/baselines/reference/es6ClassSuperCodegenBug.js
index a374778ef45..62c96f6260d 100644
--- a/tests/baselines/reference/es6ClassSuperCodegenBug.js
+++ b/tests/baselines/reference/es6ClassSuperCodegenBug.js
@@ -17,8 +17,7 @@ class B extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A(str1, str2) {
diff --git a/tests/baselines/reference/es6ClassTest.js b/tests/baselines/reference/es6ClassTest.js
index bf65840e31c..9247dfde1c3 100644
--- a/tests/baselines/reference/es6ClassTest.js
+++ b/tests/baselines/reference/es6ClassTest.js
@@ -88,8 +88,7 @@ declare module AmbientMod {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Bar = (function () {
     function Bar(n) {
diff --git a/tests/baselines/reference/es6ClassTest2.js b/tests/baselines/reference/es6ClassTest2.js
index 40f1c15c8f1..20200a692ff 100644
--- a/tests/baselines/reference/es6ClassTest2.js
+++ b/tests/baselines/reference/es6ClassTest2.js
@@ -162,8 +162,7 @@ var ccwc = new ChildClassWithoutConstructor(1, "s");
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var BasicMonster = (function () {
     function BasicMonster(name, health) {
diff --git a/tests/baselines/reference/es6ClassTest7.js b/tests/baselines/reference/es6ClassTest7.js
index c4f7e83b9a2..970e9c4fd9e 100644
--- a/tests/baselines/reference/es6ClassTest7.js
+++ b/tests/baselines/reference/es6ClassTest7.js
@@ -12,8 +12,7 @@ class Bar extends M.Foo {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Bar = (function (_super) {
     __extends(Bar, _super);
diff --git a/tests/baselines/reference/exportAssignmentOfGenericType1.js b/tests/baselines/reference/exportAssignmentOfGenericType1.js
index 983c328cd98..59fa01f2ca0 100644
--- a/tests/baselines/reference/exportAssignmentOfGenericType1.js
+++ b/tests/baselines/reference/exportAssignmentOfGenericType1.js
@@ -26,8 +26,7 @@ define(["require", "exports"], function (require, exports) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 define(["require", "exports", "exportAssignmentOfGenericType1_0"], function (require, exports, q) {
     var M = (function (_super) {
diff --git a/tests/baselines/reference/exportDeclarationInInternalModule.js b/tests/baselines/reference/exportDeclarationInInternalModule.js
index 9894f1fb194..4a1ee9b739f 100644
--- a/tests/baselines/reference/exportDeclarationInInternalModule.js
+++ b/tests/baselines/reference/exportDeclarationInInternalModule.js
@@ -22,8 +22,7 @@ var a: Bbb.SomeType;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Bbb = (function () {
     function Bbb() {
diff --git a/tests/baselines/reference/exportSpecifierAndExportedMemberDeclaration.js b/tests/baselines/reference/exportSpecifierAndExportedMemberDeclaration.js
new file mode 100644
index 00000000000..3fc40121011
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierAndExportedMemberDeclaration.js
@@ -0,0 +1,15 @@
+//// [exportSpecifierAndExportedMemberDeclaration.ts]
+declare module "m2" {
+    export module X {
+        interface I { }
+    }
+    function Y();
+    export { Y as X };
+    function Z(): X.I;
+}
+
+declare module "m2" {
+    function Z2(): X.I;
+}
+
+//// [exportSpecifierAndExportedMemberDeclaration.js]
diff --git a/tests/baselines/reference/exportSpecifierAndExportedMemberDeclaration.symbols b/tests/baselines/reference/exportSpecifierAndExportedMemberDeclaration.symbols
new file mode 100644
index 00000000000..7e2de735c47
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierAndExportedMemberDeclaration.symbols
@@ -0,0 +1,27 @@
+=== tests/cases/compiler/exportSpecifierAndExportedMemberDeclaration.ts ===
+declare module "m2" {
+    export module X {
+>X : Symbol(X, Decl(exportSpecifierAndExportedMemberDeclaration.ts, 0, 21), Decl(exportSpecifierAndExportedMemberDeclaration.ts, 5, 12))
+
+        interface I { }
+>I : Symbol(I, Decl(exportSpecifierAndExportedMemberDeclaration.ts, 1, 21))
+    }
+    function Y();
+>Y : Symbol(Y, Decl(exportSpecifierAndExportedMemberDeclaration.ts, 3, 5))
+
+    export { Y as X };
+>Y : Symbol(X, Decl(exportSpecifierAndExportedMemberDeclaration.ts, 0, 21), Decl(exportSpecifierAndExportedMemberDeclaration.ts, 5, 12))
+>X : Symbol(X, Decl(exportSpecifierAndExportedMemberDeclaration.ts, 0, 21), Decl(exportSpecifierAndExportedMemberDeclaration.ts, 5, 12))
+
+    function Z(): X.I;
+>Z : Symbol(Z, Decl(exportSpecifierAndExportedMemberDeclaration.ts, 5, 22))
+>X : Symbol(X, Decl(exportSpecifierAndExportedMemberDeclaration.ts, 0, 21), Decl(exportSpecifierAndExportedMemberDeclaration.ts, 5, 12))
+>I : Symbol(X.I, Decl(exportSpecifierAndExportedMemberDeclaration.ts, 1, 21))
+}
+
+declare module "m2" {
+    function Z2(): X.I;
+>Z2 : Symbol(Z2, Decl(exportSpecifierAndExportedMemberDeclaration.ts, 9, 21))
+>X : Symbol(X, Decl(exportSpecifierAndExportedMemberDeclaration.ts, 0, 21), Decl(exportSpecifierAndExportedMemberDeclaration.ts, 5, 12))
+>I : Symbol(X.I, Decl(exportSpecifierAndExportedMemberDeclaration.ts, 1, 21))
+}
diff --git a/tests/baselines/reference/exportSpecifierAndExportedMemberDeclaration.types b/tests/baselines/reference/exportSpecifierAndExportedMemberDeclaration.types
new file mode 100644
index 00000000000..931552819c7
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierAndExportedMemberDeclaration.types
@@ -0,0 +1,27 @@
+=== tests/cases/compiler/exportSpecifierAndExportedMemberDeclaration.ts ===
+declare module "m2" {
+    export module X {
+>X : () => any
+
+        interface I { }
+>I : I
+    }
+    function Y();
+>Y : () => any
+
+    export { Y as X };
+>Y : () => any
+>X : () => any
+
+    function Z(): X.I;
+>Z : () => X.I
+>X : any
+>I : X.I
+}
+
+declare module "m2" {
+    function Z2(): X.I;
+>Z2 : () => X.I
+>X : any
+>I : X.I
+}
diff --git a/tests/baselines/reference/exportSpecifierAndLocalMemberDeclaration.errors.txt b/tests/baselines/reference/exportSpecifierAndLocalMemberDeclaration.errors.txt
new file mode 100644
index 00000000000..eb444919f2c
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierAndLocalMemberDeclaration.errors.txt
@@ -0,0 +1,18 @@
+tests/cases/compiler/exportSpecifierAndLocalMemberDeclaration.ts(11,20): error TS2503: Cannot find namespace 'X'.
+
+
+==== tests/cases/compiler/exportSpecifierAndLocalMemberDeclaration.ts (1 errors) ====
+    declare module "m2" {
+        module X {
+            interface I { }
+        }
+        function Y();
+        export { Y as X };
+        function Z(): X.I;
+    }
+    
+    declare module "m2" {
+        function Z2(): X.I;
+                       ~
+!!! error TS2503: Cannot find namespace 'X'.
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/exportSpecifierAndLocalMemberDeclaration.js b/tests/baselines/reference/exportSpecifierAndLocalMemberDeclaration.js
new file mode 100644
index 00000000000..d99ff3627ed
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierAndLocalMemberDeclaration.js
@@ -0,0 +1,15 @@
+//// [exportSpecifierAndLocalMemberDeclaration.ts]
+declare module "m2" {
+    module X {
+        interface I { }
+    }
+    function Y();
+    export { Y as X };
+    function Z(): X.I;
+}
+
+declare module "m2" {
+    function Z2(): X.I;
+}
+
+//// [exportSpecifierAndLocalMemberDeclaration.js]
diff --git a/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration1.js b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration1.js
new file mode 100644
index 00000000000..003956e2822
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration1.js
@@ -0,0 +1,8 @@
+//// [exportSpecifierReferencingOuterDeclaration1.ts]
+declare module X { export interface bar { } }
+declare module "m" {
+    export { X };
+    export function foo(): X.bar;
+}
+
+//// [exportSpecifierReferencingOuterDeclaration1.js]
diff --git a/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration1.symbols b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration1.symbols
new file mode 100644
index 00000000000..16abde86d32
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration1.symbols
@@ -0,0 +1,14 @@
+=== tests/cases/compiler/exportSpecifierReferencingOuterDeclaration1.ts ===
+declare module X { export interface bar { } }
+>X : Symbol(X, Decl(exportSpecifierReferencingOuterDeclaration1.ts, 0, 0))
+>bar : Symbol(bar, Decl(exportSpecifierReferencingOuterDeclaration1.ts, 0, 18))
+
+declare module "m" {
+    export { X };
+>X : Symbol(X, Decl(exportSpecifierReferencingOuterDeclaration1.ts, 2, 12))
+
+    export function foo(): X.bar;
+>foo : Symbol(foo, Decl(exportSpecifierReferencingOuterDeclaration1.ts, 2, 17))
+>X : Symbol(X, Decl(exportSpecifierReferencingOuterDeclaration1.ts, 0, 0))
+>bar : Symbol(X.bar, Decl(exportSpecifierReferencingOuterDeclaration1.ts, 0, 18))
+}
diff --git a/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration1.types b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration1.types
new file mode 100644
index 00000000000..be03554a1b0
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration1.types
@@ -0,0 +1,14 @@
+=== tests/cases/compiler/exportSpecifierReferencingOuterDeclaration1.ts ===
+declare module X { export interface bar { } }
+>X : any
+>bar : bar
+
+declare module "m" {
+    export { X };
+>X : any
+
+    export function foo(): X.bar;
+>foo : () => X.bar
+>X : any
+>bar : X.bar
+}
diff --git a/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration2.js b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration2.js
new file mode 100644
index 00000000000..e8e96784083
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration2.js
@@ -0,0 +1,11 @@
+//// [tests/cases/compiler/exportSpecifierReferencingOuterDeclaration2.ts] ////
+
+//// [exportSpecifierReferencingOuterDeclaration2_A.ts]
+declare module X { export interface bar { } }
+
+//// [exportSpecifierReferencingOuterDeclaration2_B.ts]
+export { X };
+export declare function foo(): X.bar;
+
+//// [exportSpecifierReferencingOuterDeclaration2_A.js]
+//// [exportSpecifierReferencingOuterDeclaration2_B.js]
diff --git a/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration2.symbols b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration2.symbols
new file mode 100644
index 00000000000..9a57645b1cb
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration2.symbols
@@ -0,0 +1,14 @@
+=== tests/cases/compiler/exportSpecifierReferencingOuterDeclaration2_A.ts ===
+declare module X { export interface bar { } }
+>X : Symbol(X, Decl(exportSpecifierReferencingOuterDeclaration2_A.ts, 0, 0))
+>bar : Symbol(bar, Decl(exportSpecifierReferencingOuterDeclaration2_A.ts, 0, 18))
+
+=== tests/cases/compiler/exportSpecifierReferencingOuterDeclaration2_B.ts ===
+export { X };
+>X : Symbol(X, Decl(exportSpecifierReferencingOuterDeclaration2_B.ts, 0, 8))
+
+export declare function foo(): X.bar;
+>foo : Symbol(foo, Decl(exportSpecifierReferencingOuterDeclaration2_B.ts, 0, 13))
+>X : Symbol(X, Decl(exportSpecifierReferencingOuterDeclaration2_A.ts, 0, 0))
+>bar : Symbol(X.bar, Decl(exportSpecifierReferencingOuterDeclaration2_A.ts, 0, 18))
+
diff --git a/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration2.types b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration2.types
new file mode 100644
index 00000000000..fa59948c116
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration2.types
@@ -0,0 +1,14 @@
+=== tests/cases/compiler/exportSpecifierReferencingOuterDeclaration2_A.ts ===
+declare module X { export interface bar { } }
+>X : any
+>bar : bar
+
+=== tests/cases/compiler/exportSpecifierReferencingOuterDeclaration2_B.ts ===
+export { X };
+>X : any
+
+export declare function foo(): X.bar;
+>foo : () => X.bar
+>X : any
+>bar : X.bar
+
diff --git a/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration3.errors.txt b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration3.errors.txt
new file mode 100644
index 00000000000..e144c48bea4
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration3.errors.txt
@@ -0,0 +1,13 @@
+tests/cases/compiler/exportSpecifierReferencingOuterDeclaration3.ts(6,30): error TS2305: Module 'X' has no exported member 'bar'.
+
+
+==== tests/cases/compiler/exportSpecifierReferencingOuterDeclaration3.ts (1 errors) ====
+    declare module X { export interface bar { } }
+    declare module "m" {
+        module X { export interface foo { } }
+        export { X };
+        export function foo(): X.foo;
+        export function bar(): X.bar; // error
+                                 ~~~
+!!! error TS2305: Module 'X' has no exported member 'bar'.
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration3.js b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration3.js
new file mode 100644
index 00000000000..0f6fff977da
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration3.js
@@ -0,0 +1,10 @@
+//// [exportSpecifierReferencingOuterDeclaration3.ts]
+declare module X { export interface bar { } }
+declare module "m" {
+    module X { export interface foo { } }
+    export { X };
+    export function foo(): X.foo;
+    export function bar(): X.bar; // error
+}
+
+//// [exportSpecifierReferencingOuterDeclaration3.js]
diff --git a/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration4.errors.txt b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration4.errors.txt
new file mode 100644
index 00000000000..6ac67c70d17
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration4.errors.txt
@@ -0,0 +1,13 @@
+tests/cases/compiler/exportSpecifierReferencingOuterDeclaration2_B.ts(4,34): error TS2305: Module 'X' has no exported member 'bar'.
+
+
+==== tests/cases/compiler/exportSpecifierReferencingOuterDeclaration2_A.ts (0 errors) ====
+    declare module X { export interface bar { } }
+    
+==== tests/cases/compiler/exportSpecifierReferencingOuterDeclaration2_B.ts (1 errors) ====
+    declare module X { export interface foo { } }
+    export { X };
+    export declare function foo(): X.foo;
+    export declare function bar(): X.bar; // error
+                                     ~~~
+!!! error TS2305: Module 'X' has no exported member 'bar'.
\ No newline at end of file
diff --git a/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration4.js b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration4.js
new file mode 100644
index 00000000000..4edb5f711a6
--- /dev/null
+++ b/tests/baselines/reference/exportSpecifierReferencingOuterDeclaration4.js
@@ -0,0 +1,13 @@
+//// [tests/cases/compiler/exportSpecifierReferencingOuterDeclaration4.ts] ////
+
+//// [exportSpecifierReferencingOuterDeclaration2_A.ts]
+declare module X { export interface bar { } }
+
+//// [exportSpecifierReferencingOuterDeclaration2_B.ts]
+declare module X { export interface foo { } }
+export { X };
+export declare function foo(): X.foo;
+export declare function bar(): X.bar; // error
+
+//// [exportSpecifierReferencingOuterDeclaration2_A.js]
+//// [exportSpecifierReferencingOuterDeclaration2_B.js]
diff --git a/tests/baselines/reference/extBaseClass1.js b/tests/baselines/reference/extBaseClass1.js
index 9e7421b906c..07923eccc88 100644
--- a/tests/baselines/reference/extBaseClass1.js
+++ b/tests/baselines/reference/extBaseClass1.js
@@ -23,8 +23,7 @@ module N {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/extBaseClass2.js b/tests/baselines/reference/extBaseClass2.js
index e5a717bca80..6e9972c3f29 100644
--- a/tests/baselines/reference/extBaseClass2.js
+++ b/tests/baselines/reference/extBaseClass2.js
@@ -14,8 +14,7 @@ module M {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var N;
 (function (N) {
diff --git a/tests/baselines/reference/extendAndImplementTheSameBaseType.js b/tests/baselines/reference/extendAndImplementTheSameBaseType.js
index c69315dbd61..6a631ceebf8 100644
--- a/tests/baselines/reference/extendAndImplementTheSameBaseType.js
+++ b/tests/baselines/reference/extendAndImplementTheSameBaseType.js
@@ -17,8 +17,7 @@ d.foo;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/extendAndImplementTheSameBaseType2.js b/tests/baselines/reference/extendAndImplementTheSameBaseType2.js
index 06ea74880c2..42cf785c0b0 100644
--- a/tests/baselines/reference/extendAndImplementTheSameBaseType2.js
+++ b/tests/baselines/reference/extendAndImplementTheSameBaseType2.js
@@ -20,8 +20,7 @@ var r4: number = d.bar();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/extendBaseClassBeforeItsDeclared.js b/tests/baselines/reference/extendBaseClassBeforeItsDeclared.js
index 7598d771bac..d8c54b58d7e 100644
--- a/tests/baselines/reference/extendBaseClassBeforeItsDeclared.js
+++ b/tests/baselines/reference/extendBaseClassBeforeItsDeclared.js
@@ -7,8 +7,7 @@ class base { constructor (public n: number) { } }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var derived = (function (_super) {
     __extends(derived, _super);
diff --git a/tests/baselines/reference/extendNonClassSymbol1.js b/tests/baselines/reference/extendNonClassSymbol1.js
index 59da2d7ca2b..29408686068 100644
--- a/tests/baselines/reference/extendNonClassSymbol1.js
+++ b/tests/baselines/reference/extendNonClassSymbol1.js
@@ -7,8 +7,7 @@ class C extends x { } // error, could not find symbol xs
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/extendNonClassSymbol2.errors.txt b/tests/baselines/reference/extendNonClassSymbol2.errors.txt
index 882a8b447f8..5554ff60a26 100644
--- a/tests/baselines/reference/extendNonClassSymbol2.errors.txt
+++ b/tests/baselines/reference/extendNonClassSymbol2.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/extendNonClassSymbol2.ts(5,17): error TS2507: Base expression is not of a constructor function type.
+tests/cases/compiler/extendNonClassSymbol2.ts(5,17): error TS2507: Type '() => void' is not a constructor function type.
 
 
 ==== tests/cases/compiler/extendNonClassSymbol2.ts (1 errors) ====
@@ -8,4 +8,4 @@ tests/cases/compiler/extendNonClassSymbol2.ts(5,17): error TS2507: Base expressi
     var x = new Foo(); // legal, considered a constructor function
     class C extends Foo {} // error, could not find symbol Foo
                     ~~~
-!!! error TS2507: Base expression is not of a constructor function type.
\ No newline at end of file
+!!! error TS2507: Type '() => void' is not a constructor function type.
\ No newline at end of file
diff --git a/tests/baselines/reference/extendNonClassSymbol2.js b/tests/baselines/reference/extendNonClassSymbol2.js
index 830994e3d26..a65eeca612a 100644
--- a/tests/baselines/reference/extendNonClassSymbol2.js
+++ b/tests/baselines/reference/extendNonClassSymbol2.js
@@ -9,8 +9,7 @@ class C extends Foo {} // error, could not find symbol Foo
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function Foo() {
     this.x = 1;
diff --git a/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.js b/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.js
index 0bf86390b74..297a7527ec0 100644
--- a/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.js
+++ b/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.js
@@ -43,8 +43,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("extendingClassFromAliasAndUsageInIndexer_backbone");
 var VisualizationModel = (function (_super) {
@@ -59,8 +58,7 @@ exports.VisualizationModel = VisualizationModel;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("extendingClassFromAliasAndUsageInIndexer_backbone");
 var VisualizationModel = (function (_super) {
diff --git a/tests/baselines/reference/extendsClauseAlreadySeen.js b/tests/baselines/reference/extendsClauseAlreadySeen.js
index 3e7151b8e0d..ed6602c116a 100644
--- a/tests/baselines/reference/extendsClauseAlreadySeen.js
+++ b/tests/baselines/reference/extendsClauseAlreadySeen.js
@@ -10,8 +10,7 @@ class D extends C extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/extendsClauseAlreadySeen2.js b/tests/baselines/reference/extendsClauseAlreadySeen2.js
index 9ee428c36ed..2c77f4e673f 100644
--- a/tests/baselines/reference/extendsClauseAlreadySeen2.js
+++ b/tests/baselines/reference/extendsClauseAlreadySeen2.js
@@ -10,8 +10,7 @@ class D<T> extends C<number> extends C<string> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/for-inStatements.js b/tests/baselines/reference/for-inStatements.js
index 749c7b47b34..d735a37ba97 100644
--- a/tests/baselines/reference/for-inStatements.js
+++ b/tests/baselines/reference/for-inStatements.js
@@ -84,8 +84,7 @@ for (var x in Color.Blue) { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var aString;
 for (aString in {}) { }
diff --git a/tests/baselines/reference/for-inStatementsInvalid.js b/tests/baselines/reference/for-inStatementsInvalid.js
index e1806272790..93b9fb9b97f 100644
--- a/tests/baselines/reference/for-inStatementsInvalid.js
+++ b/tests/baselines/reference/for-inStatementsInvalid.js
@@ -67,8 +67,7 @@ for (var x in i[42]) { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var aNumber;
 for (aNumber in {}) { }
diff --git a/tests/baselines/reference/forStatementsMultipleInvalidDecl.js b/tests/baselines/reference/forStatementsMultipleInvalidDecl.js
index b00e8acef14..1dde9981880 100644
--- a/tests/baselines/reference/forStatementsMultipleInvalidDecl.js
+++ b/tests/baselines/reference/forStatementsMultipleInvalidDecl.js
@@ -57,8 +57,7 @@ for( var m = M.A;;){}
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/functionImplementationErrors.js b/tests/baselines/reference/functionImplementationErrors.js
index 6c1daffdaf1..42be5f21458 100644
--- a/tests/baselines/reference/functionImplementationErrors.js
+++ b/tests/baselines/reference/functionImplementationErrors.js
@@ -77,8 +77,7 @@ var f13 = () => {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // FunctionExpression with no return type annotation with multiple return statements with unrelated types
 var f1 = function () {
diff --git a/tests/baselines/reference/functionImplementations.js b/tests/baselines/reference/functionImplementations.js
index 0370c4c0027..3fc040650e4 100644
--- a/tests/baselines/reference/functionImplementations.js
+++ b/tests/baselines/reference/functionImplementations.js
@@ -160,8 +160,7 @@ var f12: (x: number) => any = x => { // should be (x: number) => Base | AnotherC
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // FunctionExpression with no return type annotation and no return statement returns void
 var v = function () { }();
diff --git a/tests/baselines/reference/functionSubtypingOfVarArgs.js b/tests/baselines/reference/functionSubtypingOfVarArgs.js
index b0168975677..ddcb0570908 100644
--- a/tests/baselines/reference/functionSubtypingOfVarArgs.js
+++ b/tests/baselines/reference/functionSubtypingOfVarArgs.js
@@ -18,8 +18,7 @@ class StringEvent extends EventBase { // should work
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var EventBase = (function () {
     function EventBase() {
diff --git a/tests/baselines/reference/functionSubtypingOfVarArgs2.js b/tests/baselines/reference/functionSubtypingOfVarArgs2.js
index 7efd35cc2d2..d04a5b97dae 100644
--- a/tests/baselines/reference/functionSubtypingOfVarArgs2.js
+++ b/tests/baselines/reference/functionSubtypingOfVarArgs2.js
@@ -18,8 +18,7 @@ class StringEvent extends EventBase {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var EventBase = (function () {
     function EventBase() {
diff --git a/tests/baselines/reference/generatedContextualTyping.js b/tests/baselines/reference/generatedContextualTyping.js
index 3c2c704ddb0..1f7d2b8035f 100644
--- a/tests/baselines/reference/generatedContextualTyping.js
+++ b/tests/baselines/reference/generatedContextualTyping.js
@@ -358,8 +358,7 @@ var x356 = function(n: Genric<Base>) { }; x356({ func: n => { return [d1, d2]; }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/generatorTypeCheck40.errors.txt b/tests/baselines/reference/generatorTypeCheck40.errors.txt
index 6341ec9ae0a..ba93862c8d5 100644
--- a/tests/baselines/reference/generatorTypeCheck40.errors.txt
+++ b/tests/baselines/reference/generatorTypeCheck40.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck40.ts(2,21): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck40.ts(2,21): error TS2507: Type 'any' is not a constructor function type.
 tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck40.ts(2,22): error TS1163: A 'yield' expression is only allowed in a generator body.
 
 
@@ -6,7 +6,7 @@ tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck40.ts(2,22): erro
     function* g() {
         class C extends (yield 0) { }
                         ~~~~~~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'any' is not a constructor function type.
                          ~~~~~
 !!! error TS1163: A 'yield' expression is only allowed in a generator body.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/generatorTypeCheck60.errors.txt b/tests/baselines/reference/generatorTypeCheck60.errors.txt
index 4d230a81b5b..5330cd186b7 100644
--- a/tests/baselines/reference/generatorTypeCheck60.errors.txt
+++ b/tests/baselines/reference/generatorTypeCheck60.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck60.ts(2,21): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck60.ts(2,21): error TS2507: Type 'any' is not a constructor function type.
 tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck60.ts(2,22): error TS1163: A 'yield' expression is only allowed in a generator body.
 
 
@@ -6,7 +6,7 @@ tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck60.ts(2,22): erro
     function* g() {
         class C extends (yield) {};
                         ~~~~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'any' is not a constructor function type.
                          ~~~~~
 !!! error TS1163: A 'yield' expression is only allowed in a generator body.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/genericBaseClassLiteralProperty.js b/tests/baselines/reference/genericBaseClassLiteralProperty.js
index 5e365531461..f8a5f78e753 100644
--- a/tests/baselines/reference/genericBaseClassLiteralProperty.js
+++ b/tests/baselines/reference/genericBaseClassLiteralProperty.js
@@ -16,8 +16,7 @@ class SubClass extends BaseClass<number> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var BaseClass = (function () {
     function BaseClass() {
diff --git a/tests/baselines/reference/genericBaseClassLiteralProperty2.js b/tests/baselines/reference/genericBaseClassLiteralProperty2.js
index 8a19d857bb6..d5c480955d8 100644
--- a/tests/baselines/reference/genericBaseClassLiteralProperty2.js
+++ b/tests/baselines/reference/genericBaseClassLiteralProperty2.js
@@ -19,8 +19,7 @@ class DataView2 extends BaseCollection2<CollectionItem2> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var CollectionItem2 = (function () {
     function CollectionItem2() {
diff --git a/tests/baselines/reference/genericCallWithConstraintsTypeArgumentInference.js b/tests/baselines/reference/genericCallWithConstraintsTypeArgumentInference.js
index f00468dcbc5..9df55756ee2 100644
--- a/tests/baselines/reference/genericCallWithConstraintsTypeArgumentInference.js
+++ b/tests/baselines/reference/genericCallWithConstraintsTypeArgumentInference.js
@@ -112,8 +112,7 @@ var r11 = i.foo8(); // Base
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/genericCallWithObjectTypeArgs2.js b/tests/baselines/reference/genericCallWithObjectTypeArgs2.js
index 910e3860b49..bded01ead69 100644
--- a/tests/baselines/reference/genericCallWithObjectTypeArgs2.js
+++ b/tests/baselines/reference/genericCallWithObjectTypeArgs2.js
@@ -36,8 +36,7 @@ var r4 = f2(i); // Base => Derived
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/genericCallWithObjectTypeArgsAndConstraints2.js b/tests/baselines/reference/genericCallWithObjectTypeArgsAndConstraints2.js
index 9cb2425f9d0..96c2f9300db 100644
--- a/tests/baselines/reference/genericCallWithObjectTypeArgsAndConstraints2.js
+++ b/tests/baselines/reference/genericCallWithObjectTypeArgsAndConstraints2.js
@@ -44,8 +44,7 @@ var r7 = f3(null, x => x); // any
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/genericCallWithObjectTypeArgsAndConstraints3.js b/tests/baselines/reference/genericCallWithObjectTypeArgsAndConstraints3.js
index 3c5a4c24b53..daaa2f5c0eb 100644
--- a/tests/baselines/reference/genericCallWithObjectTypeArgsAndConstraints3.js
+++ b/tests/baselines/reference/genericCallWithObjectTypeArgsAndConstraints3.js
@@ -42,8 +42,7 @@ var r6 = f3(x => x, null);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/genericCallbacksAndClassHierarchy.js b/tests/baselines/reference/genericCallbacksAndClassHierarchy.js
index 16abb2683e7..093757d513d 100644
--- a/tests/baselines/reference/genericCallbacksAndClassHierarchy.js
+++ b/tests/baselines/reference/genericCallbacksAndClassHierarchy.js
@@ -27,8 +27,7 @@ module M {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/genericClassInheritsConstructorFromNonGenericClass.js b/tests/baselines/reference/genericClassInheritsConstructorFromNonGenericClass.js
index 22bb975e7d7..f77f60a2fb9 100644
--- a/tests/baselines/reference/genericClassInheritsConstructorFromNonGenericClass.js
+++ b/tests/baselines/reference/genericClassInheritsConstructorFromNonGenericClass.js
@@ -9,8 +9,7 @@ class C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function (_super) {
     __extends(A, _super);
diff --git a/tests/baselines/reference/genericClassPropertyInheritanceSpecialization.js b/tests/baselines/reference/genericClassPropertyInheritanceSpecialization.js
index 43d1e53a615..69261747244 100644
--- a/tests/baselines/reference/genericClassPropertyInheritanceSpecialization.js
+++ b/tests/baselines/reference/genericClassPropertyInheritanceSpecialization.js
@@ -79,8 +79,7 @@ class ViewModel<TValue> implements Contract<TValue> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Portal;
 (function (Portal) {
diff --git a/tests/baselines/reference/genericClassStaticMethod.js b/tests/baselines/reference/genericClassStaticMethod.js
index 23e1874c0ed..aed721aa7d5 100644
--- a/tests/baselines/reference/genericClassStaticMethod.js
+++ b/tests/baselines/reference/genericClassStaticMethod.js
@@ -14,8 +14,7 @@ class Bar<T> extends Foo<T> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/genericClasses3.js b/tests/baselines/reference/genericClasses3.js
index 373052d78e3..14ffab2f6f6 100644
--- a/tests/baselines/reference/genericClasses3.js
+++ b/tests/baselines/reference/genericClasses3.js
@@ -21,8 +21,7 @@ var z = v2.b;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var B = (function () {
     function B() {
diff --git a/tests/baselines/reference/genericConstraintOnExtendedBuiltinTypes.js b/tests/baselines/reference/genericConstraintOnExtendedBuiltinTypes.js
index 561c24cd50e..b4e56933775 100644
--- a/tests/baselines/reference/genericConstraintOnExtendedBuiltinTypes.js
+++ b/tests/baselines/reference/genericConstraintOnExtendedBuiltinTypes.js
@@ -30,8 +30,7 @@ module EndGate.Tweening {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var EndGate;
 (function (EndGate) {
diff --git a/tests/baselines/reference/genericConstraintOnExtendedBuiltinTypes2.js b/tests/baselines/reference/genericConstraintOnExtendedBuiltinTypes2.js
index 2420e082e3d..54a807a8e87 100644
--- a/tests/baselines/reference/genericConstraintOnExtendedBuiltinTypes2.js
+++ b/tests/baselines/reference/genericConstraintOnExtendedBuiltinTypes2.js
@@ -29,8 +29,7 @@ module EndGate.Tweening {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var EndGate;
 (function (EndGate) {
diff --git a/tests/baselines/reference/genericDerivedTypeWithSpecializedBase.js b/tests/baselines/reference/genericDerivedTypeWithSpecializedBase.js
index 69ae509bf54..eb27365ebc5 100644
--- a/tests/baselines/reference/genericDerivedTypeWithSpecializedBase.js
+++ b/tests/baselines/reference/genericDerivedTypeWithSpecializedBase.js
@@ -16,8 +16,7 @@ x = y;  // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/genericDerivedTypeWithSpecializedBase2.js b/tests/baselines/reference/genericDerivedTypeWithSpecializedBase2.js
index 1c4f27b5ebe..be94a778858 100644
--- a/tests/baselines/reference/genericDerivedTypeWithSpecializedBase2.js
+++ b/tests/baselines/reference/genericDerivedTypeWithSpecializedBase2.js
@@ -16,8 +16,7 @@ x = y;  // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/genericPrototypeProperty2.js b/tests/baselines/reference/genericPrototypeProperty2.js
index b91b345481e..cbe33431ca4 100644
--- a/tests/baselines/reference/genericPrototypeProperty2.js
+++ b/tests/baselines/reference/genericPrototypeProperty2.js
@@ -19,8 +19,7 @@ class MyEventWrapper extends BaseEventWrapper {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var BaseEvent = (function () {
     function BaseEvent() {
diff --git a/tests/baselines/reference/genericPrototypeProperty3.js b/tests/baselines/reference/genericPrototypeProperty3.js
index de093886ea4..6447a4e0ac2 100644
--- a/tests/baselines/reference/genericPrototypeProperty3.js
+++ b/tests/baselines/reference/genericPrototypeProperty3.js
@@ -18,8 +18,7 @@ class MyEventWrapper extends BaseEventWrapper {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var BaseEvent = (function () {
     function BaseEvent() {
diff --git a/tests/baselines/reference/genericRecursiveImplicitConstructorErrors2.js b/tests/baselines/reference/genericRecursiveImplicitConstructorErrors2.js
index b73239626d0..a1f7566f1c0 100644
--- a/tests/baselines/reference/genericRecursiveImplicitConstructorErrors2.js
+++ b/tests/baselines/reference/genericRecursiveImplicitConstructorErrors2.js
@@ -30,8 +30,7 @@ module TypeScript2 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var TypeScript2;
 (function (TypeScript2) {
diff --git a/tests/baselines/reference/genericRecursiveImplicitConstructorErrors3.js b/tests/baselines/reference/genericRecursiveImplicitConstructorErrors3.js
index 0d4a3315acd..a0229e19925 100644
--- a/tests/baselines/reference/genericRecursiveImplicitConstructorErrors3.js
+++ b/tests/baselines/reference/genericRecursiveImplicitConstructorErrors3.js
@@ -34,8 +34,7 @@ module TypeScript {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var TypeScript;
 (function (TypeScript) {
diff --git a/tests/baselines/reference/genericTypeAssertions2.js b/tests/baselines/reference/genericTypeAssertions2.js
index a3b88f599b9..22ff708592e 100644
--- a/tests/baselines/reference/genericTypeAssertions2.js
+++ b/tests/baselines/reference/genericTypeAssertions2.js
@@ -17,8 +17,7 @@ var r5: A<number> = <A<number>>[]; // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/genericTypeAssertions4.js b/tests/baselines/reference/genericTypeAssertions4.js
index 95ca5482b2e..d6d8672283c 100644
--- a/tests/baselines/reference/genericTypeAssertions4.js
+++ b/tests/baselines/reference/genericTypeAssertions4.js
@@ -29,8 +29,7 @@ function foo2<T extends A>(x: T) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/genericTypeAssertions6.js b/tests/baselines/reference/genericTypeAssertions6.js
index d19da506680..30a5d5ff5e5 100644
--- a/tests/baselines/reference/genericTypeAssertions6.js
+++ b/tests/baselines/reference/genericTypeAssertions6.js
@@ -28,8 +28,7 @@ var c: A<Date, Date> = <A<Date, Date>>b;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A(x) {
diff --git a/tests/baselines/reference/genericTypeConstraints.js b/tests/baselines/reference/genericTypeConstraints.js
index 6f0f235ccb8..eb8bed1fb92 100644
--- a/tests/baselines/reference/genericTypeConstraints.js
+++ b/tests/baselines/reference/genericTypeConstraints.js
@@ -17,8 +17,7 @@ class BarExtended extends Bar<FooExtended> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/genericTypeReferenceWithoutTypeArgument.js b/tests/baselines/reference/genericTypeReferenceWithoutTypeArgument.js
index 5ec0a25af3d..0cbf3581706 100644
--- a/tests/baselines/reference/genericTypeReferenceWithoutTypeArgument.js
+++ b/tests/baselines/reference/genericTypeReferenceWithoutTypeArgument.js
@@ -43,8 +43,7 @@ var k = <M.E>null;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/genericTypeReferenceWithoutTypeArgument2.js b/tests/baselines/reference/genericTypeReferenceWithoutTypeArgument2.js
index 2f36a74de76..355030caa1b 100644
--- a/tests/baselines/reference/genericTypeReferenceWithoutTypeArgument2.js
+++ b/tests/baselines/reference/genericTypeReferenceWithoutTypeArgument2.js
@@ -43,8 +43,7 @@ var k = <M.E>null;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var c;
 var a;
diff --git a/tests/baselines/reference/genericWithIndexerOfTypeParameterType2.js b/tests/baselines/reference/genericWithIndexerOfTypeParameterType2.js
index 8142cd86407..2457d4a534e 100644
--- a/tests/baselines/reference/genericWithIndexerOfTypeParameterType2.js
+++ b/tests/baselines/reference/genericWithIndexerOfTypeParameterType2.js
@@ -18,8 +18,7 @@ export class ListItem extends CollectionItem {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 define(["require", "exports"], function (require, exports) {
     var Collection = (function () {
diff --git a/tests/baselines/reference/heterogeneousArrayLiterals.js b/tests/baselines/reference/heterogeneousArrayLiterals.js
index 26d1b09a6fc..45ea6429979 100644
--- a/tests/baselines/reference/heterogeneousArrayLiterals.js
+++ b/tests/baselines/reference/heterogeneousArrayLiterals.js
@@ -136,8 +136,7 @@ function foo4<T extends Base, U extends Base>(t: T, u: U) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = [1, '']; // {}[]
 var b = [1, null]; // number[]
diff --git a/tests/baselines/reference/ifDoWhileStatements.js b/tests/baselines/reference/ifDoWhileStatements.js
index d389f705707..020d3f053d1 100644
--- a/tests/baselines/reference/ifDoWhileStatements.js
+++ b/tests/baselines/reference/ifDoWhileStatements.js
@@ -166,8 +166,7 @@ do { }while(fn)
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/illegalSuperCallsInConstructor.js b/tests/baselines/reference/illegalSuperCallsInConstructor.js
index 57a382fe625..c3a52473744 100644
--- a/tests/baselines/reference/illegalSuperCallsInConstructor.js
+++ b/tests/baselines/reference/illegalSuperCallsInConstructor.js
@@ -24,8 +24,7 @@ class Derived extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/implementClausePrecedingExtends.js b/tests/baselines/reference/implementClausePrecedingExtends.js
index 7501c231dc8..a929c2fb966 100644
--- a/tests/baselines/reference/implementClausePrecedingExtends.js
+++ b/tests/baselines/reference/implementClausePrecedingExtends.js
@@ -6,8 +6,7 @@ class D implements C extends C { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/implementingAnInterfaceExtendingClassWithPrivates2.js b/tests/baselines/reference/implementingAnInterfaceExtendingClassWithPrivates2.js
index 3d80d344850..cfa5ccf4150 100644
--- a/tests/baselines/reference/implementingAnInterfaceExtendingClassWithPrivates2.js
+++ b/tests/baselines/reference/implementingAnInterfaceExtendingClassWithPrivates2.js
@@ -89,8 +89,7 @@ module M2 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/implementingAnInterfaceExtendingClassWithProtecteds.js b/tests/baselines/reference/implementingAnInterfaceExtendingClassWithProtecteds.js
index 1fa40bf7aa2..39f30424321 100644
--- a/tests/baselines/reference/implementingAnInterfaceExtendingClassWithProtecteds.js
+++ b/tests/baselines/reference/implementingAnInterfaceExtendingClassWithProtecteds.js
@@ -45,8 +45,7 @@ class Bar8 extends Foo implements I {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/importAsBaseClass.errors.txt b/tests/baselines/reference/importAsBaseClass.errors.txt
index 4b923ea2323..835fd143f70 100644
--- a/tests/baselines/reference/importAsBaseClass.errors.txt
+++ b/tests/baselines/reference/importAsBaseClass.errors.txt
@@ -1,11 +1,11 @@
-tests/cases/compiler/importAsBaseClass_1.ts(2,21): error TS2507: Base expression is not of a constructor function type.
+tests/cases/compiler/importAsBaseClass_1.ts(2,21): error TS2507: Type 'typeof "tests/cases/compiler/importAsBaseClass_0"' is not a constructor function type.
 
 
 ==== tests/cases/compiler/importAsBaseClass_1.ts (1 errors) ====
     import Greeter = require("importAsBaseClass_0");
     class Hello extends Greeter { }
                         ~~~~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'typeof "tests/cases/compiler/importAsBaseClass_0"' is not a constructor function type.
     
 ==== tests/cases/compiler/importAsBaseClass_0.ts (0 errors) ====
     export class Greeter {
diff --git a/tests/baselines/reference/importAsBaseClass.js b/tests/baselines/reference/importAsBaseClass.js
index b40fd563733..b79905911b1 100644
--- a/tests/baselines/reference/importAsBaseClass.js
+++ b/tests/baselines/reference/importAsBaseClass.js
@@ -22,8 +22,7 @@ exports.Greeter = Greeter;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Greeter = require("importAsBaseClass_0");
 var Hello = (function (_super) {
diff --git a/tests/baselines/reference/importShadowsGlobalName.js b/tests/baselines/reference/importShadowsGlobalName.js
index 6db46eb41b1..fe37e938a5a 100644
--- a/tests/baselines/reference/importShadowsGlobalName.js
+++ b/tests/baselines/reference/importShadowsGlobalName.js
@@ -23,8 +23,7 @@ define(["require", "exports"], function (require, exports) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 define(["require", "exports", 'Foo'], function (require, exports, Error) {
     var Bar = (function (_super) {
diff --git a/tests/baselines/reference/importUsedInExtendsList1.js b/tests/baselines/reference/importUsedInExtendsList1.js
index 3e07ee084f3..e86b1a41456 100644
--- a/tests/baselines/reference/importUsedInExtendsList1.js
+++ b/tests/baselines/reference/importUsedInExtendsList1.js
@@ -22,8 +22,7 @@ exports.Super = Super;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 ///<reference path='importUsedInExtendsList1_require.ts'/>
 var foo = require('importUsedInExtendsList1_require');
diff --git a/tests/baselines/reference/indexerConstraints2.js b/tests/baselines/reference/indexerConstraints2.js
index 7d3966688db..7e662bc66cc 100644
--- a/tests/baselines/reference/indexerConstraints2.js
+++ b/tests/baselines/reference/indexerConstraints2.js
@@ -32,8 +32,7 @@ class K extends J {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/indirectSelfReference.js b/tests/baselines/reference/indirectSelfReference.js
index 3652d2962d0..bd838ed8810 100644
--- a/tests/baselines/reference/indirectSelfReference.js
+++ b/tests/baselines/reference/indirectSelfReference.js
@@ -6,8 +6,7 @@ class b extends a{ }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function (_super) {
     __extends(a, _super);
diff --git a/tests/baselines/reference/indirectSelfReferenceGeneric.js b/tests/baselines/reference/indirectSelfReferenceGeneric.js
index 079a37dc201..c9b4478ec13 100644
--- a/tests/baselines/reference/indirectSelfReferenceGeneric.js
+++ b/tests/baselines/reference/indirectSelfReferenceGeneric.js
@@ -6,8 +6,7 @@ class b<T> extends a<T> { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function (_super) {
     __extends(a, _super);
diff --git a/tests/baselines/reference/infinitelyExpandingTypesNonGenericBase.js b/tests/baselines/reference/infinitelyExpandingTypesNonGenericBase.js
index 71390b03c83..f057b649cb6 100644
--- a/tests/baselines/reference/infinitelyExpandingTypesNonGenericBase.js
+++ b/tests/baselines/reference/infinitelyExpandingTypesNonGenericBase.js
@@ -28,8 +28,7 @@ o(A);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Functionality = (function () {
     function Functionality() {
diff --git a/tests/baselines/reference/inheritFromGenericTypeParameter.js b/tests/baselines/reference/inheritFromGenericTypeParameter.js
index ccf445a26bf..ec6be00785f 100644
--- a/tests/baselines/reference/inheritFromGenericTypeParameter.js
+++ b/tests/baselines/reference/inheritFromGenericTypeParameter.js
@@ -6,8 +6,7 @@ interface I<T> extends T { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/inheritSameNamePrivatePropertiesFromSameOrigin.js b/tests/baselines/reference/inheritSameNamePrivatePropertiesFromSameOrigin.js
index 850741c3666..93494c7256e 100644
--- a/tests/baselines/reference/inheritSameNamePrivatePropertiesFromSameOrigin.js
+++ b/tests/baselines/reference/inheritSameNamePrivatePropertiesFromSameOrigin.js
@@ -14,8 +14,7 @@ interface A extends C, C2 { // ok
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var B = (function () {
     function B() {
diff --git a/tests/baselines/reference/inheritance.js b/tests/baselines/reference/inheritance.js
index f2b5be9335e..b581ae894ae 100644
--- a/tests/baselines/reference/inheritance.js
+++ b/tests/baselines/reference/inheritance.js
@@ -38,8 +38,7 @@ class Baad extends Good {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var B1 = (function () {
     function B1() {
diff --git a/tests/baselines/reference/inheritance1.js b/tests/baselines/reference/inheritance1.js
index e0d4fa974c5..aa7775b9904 100644
--- a/tests/baselines/reference/inheritance1.js
+++ b/tests/baselines/reference/inheritance1.js
@@ -65,8 +65,7 @@ l1 = c;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Control = (function () {
     function Control() {
diff --git a/tests/baselines/reference/inheritanceGrandParentPrivateMemberCollision.js b/tests/baselines/reference/inheritanceGrandParentPrivateMemberCollision.js
index 0f016233ef3..927ae969049 100644
--- a/tests/baselines/reference/inheritanceGrandParentPrivateMemberCollision.js
+++ b/tests/baselines/reference/inheritanceGrandParentPrivateMemberCollision.js
@@ -14,8 +14,7 @@ class C extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/inheritanceGrandParentPrivateMemberCollisionWithPublicMember.js b/tests/baselines/reference/inheritanceGrandParentPrivateMemberCollisionWithPublicMember.js
index 596982a4794..05d8dc2a541 100644
--- a/tests/baselines/reference/inheritanceGrandParentPrivateMemberCollisionWithPublicMember.js
+++ b/tests/baselines/reference/inheritanceGrandParentPrivateMemberCollisionWithPublicMember.js
@@ -14,8 +14,7 @@ class C extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/inheritanceGrandParentPublicMemberCollisionWithPrivateMember.js b/tests/baselines/reference/inheritanceGrandParentPublicMemberCollisionWithPrivateMember.js
index ec8ae03b3e3..ddd87251f9f 100644
--- a/tests/baselines/reference/inheritanceGrandParentPublicMemberCollisionWithPrivateMember.js
+++ b/tests/baselines/reference/inheritanceGrandParentPublicMemberCollisionWithPrivateMember.js
@@ -14,8 +14,7 @@ class C extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/inheritanceMemberAccessorOverridingAccessor.js b/tests/baselines/reference/inheritanceMemberAccessorOverridingAccessor.js
index 2da2bcbe6fe..eaf34df921b 100644
--- a/tests/baselines/reference/inheritanceMemberAccessorOverridingAccessor.js
+++ b/tests/baselines/reference/inheritanceMemberAccessorOverridingAccessor.js
@@ -21,8 +21,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceMemberAccessorOverridingMethod.js b/tests/baselines/reference/inheritanceMemberAccessorOverridingMethod.js
index 8b58a7f2b35..cd79d8c6964 100644
--- a/tests/baselines/reference/inheritanceMemberAccessorOverridingMethod.js
+++ b/tests/baselines/reference/inheritanceMemberAccessorOverridingMethod.js
@@ -18,8 +18,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceMemberAccessorOverridingProperty.js b/tests/baselines/reference/inheritanceMemberAccessorOverridingProperty.js
index 1864e62b237..18c1ab33952 100644
--- a/tests/baselines/reference/inheritanceMemberAccessorOverridingProperty.js
+++ b/tests/baselines/reference/inheritanceMemberAccessorOverridingProperty.js
@@ -16,8 +16,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceMemberFuncOverridingAccessor.js b/tests/baselines/reference/inheritanceMemberFuncOverridingAccessor.js
index 0b24db92a35..5c254251718 100644
--- a/tests/baselines/reference/inheritanceMemberFuncOverridingAccessor.js
+++ b/tests/baselines/reference/inheritanceMemberFuncOverridingAccessor.js
@@ -18,8 +18,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceMemberFuncOverridingMethod.js b/tests/baselines/reference/inheritanceMemberFuncOverridingMethod.js
index bf1186a5cde..e2d3d9551c2 100644
--- a/tests/baselines/reference/inheritanceMemberFuncOverridingMethod.js
+++ b/tests/baselines/reference/inheritanceMemberFuncOverridingMethod.js
@@ -15,8 +15,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceMemberFuncOverridingProperty.js b/tests/baselines/reference/inheritanceMemberFuncOverridingProperty.js
index 2ecf7edb0e8..b1d64aeb2c8 100644
--- a/tests/baselines/reference/inheritanceMemberFuncOverridingProperty.js
+++ b/tests/baselines/reference/inheritanceMemberFuncOverridingProperty.js
@@ -13,8 +13,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceMemberPropertyOverridingAccessor.js b/tests/baselines/reference/inheritanceMemberPropertyOverridingAccessor.js
index 512ca023dee..bfa5d3fb801 100644
--- a/tests/baselines/reference/inheritanceMemberPropertyOverridingAccessor.js
+++ b/tests/baselines/reference/inheritanceMemberPropertyOverridingAccessor.js
@@ -17,8 +17,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceMemberPropertyOverridingMethod.js b/tests/baselines/reference/inheritanceMemberPropertyOverridingMethod.js
index 975727031e3..d84f4879632 100644
--- a/tests/baselines/reference/inheritanceMemberPropertyOverridingMethod.js
+++ b/tests/baselines/reference/inheritanceMemberPropertyOverridingMethod.js
@@ -13,8 +13,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceMemberPropertyOverridingProperty.js b/tests/baselines/reference/inheritanceMemberPropertyOverridingProperty.js
index b924932e0b4..8677d502273 100644
--- a/tests/baselines/reference/inheritanceMemberPropertyOverridingProperty.js
+++ b/tests/baselines/reference/inheritanceMemberPropertyOverridingProperty.js
@@ -11,8 +11,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceOfGenericConstructorMethod1.js b/tests/baselines/reference/inheritanceOfGenericConstructorMethod1.js
index d62c62410b7..73d3b4aa6cb 100644
--- a/tests/baselines/reference/inheritanceOfGenericConstructorMethod1.js
+++ b/tests/baselines/reference/inheritanceOfGenericConstructorMethod1.js
@@ -11,8 +11,7 @@ var b3 = new B<Date>(); // error, could not select overload for 'new' expression
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/inheritanceOfGenericConstructorMethod2.js b/tests/baselines/reference/inheritanceOfGenericConstructorMethod2.js
index c54f8b4d317..e7e6228392c 100644
--- a/tests/baselines/reference/inheritanceOfGenericConstructorMethod2.js
+++ b/tests/baselines/reference/inheritanceOfGenericConstructorMethod2.js
@@ -18,8 +18,7 @@ var n3 = new N.D2(); // no error, D2<any>
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/inheritanceStaticAccessorOverridingAccessor.js b/tests/baselines/reference/inheritanceStaticAccessorOverridingAccessor.js
index 120efc11e27..32f1d20eda1 100644
--- a/tests/baselines/reference/inheritanceStaticAccessorOverridingAccessor.js
+++ b/tests/baselines/reference/inheritanceStaticAccessorOverridingAccessor.js
@@ -21,8 +21,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticAccessorOverridingMethod.js b/tests/baselines/reference/inheritanceStaticAccessorOverridingMethod.js
index 7200f37f94b..7a1a86ced18 100644
--- a/tests/baselines/reference/inheritanceStaticAccessorOverridingMethod.js
+++ b/tests/baselines/reference/inheritanceStaticAccessorOverridingMethod.js
@@ -18,8 +18,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticAccessorOverridingProperty.js b/tests/baselines/reference/inheritanceStaticAccessorOverridingProperty.js
index 2fd5e18dab9..8a142d41c57 100644
--- a/tests/baselines/reference/inheritanceStaticAccessorOverridingProperty.js
+++ b/tests/baselines/reference/inheritanceStaticAccessorOverridingProperty.js
@@ -16,8 +16,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticFuncOverridingAccessor.js b/tests/baselines/reference/inheritanceStaticFuncOverridingAccessor.js
index 812ac57bfe4..7c08ec7649e 100644
--- a/tests/baselines/reference/inheritanceStaticFuncOverridingAccessor.js
+++ b/tests/baselines/reference/inheritanceStaticFuncOverridingAccessor.js
@@ -18,8 +18,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticFuncOverridingAccessorOfFuncType.js b/tests/baselines/reference/inheritanceStaticFuncOverridingAccessorOfFuncType.js
index 224c0326a87..acde620c100 100644
--- a/tests/baselines/reference/inheritanceStaticFuncOverridingAccessorOfFuncType.js
+++ b/tests/baselines/reference/inheritanceStaticFuncOverridingAccessorOfFuncType.js
@@ -15,8 +15,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticFuncOverridingMethod.js b/tests/baselines/reference/inheritanceStaticFuncOverridingMethod.js
index 375f07fd905..abd4d7c1498 100644
--- a/tests/baselines/reference/inheritanceStaticFuncOverridingMethod.js
+++ b/tests/baselines/reference/inheritanceStaticFuncOverridingMethod.js
@@ -15,8 +15,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticFuncOverridingProperty.js b/tests/baselines/reference/inheritanceStaticFuncOverridingProperty.js
index c4d3f7ca420..c2d095e5527 100644
--- a/tests/baselines/reference/inheritanceStaticFuncOverridingProperty.js
+++ b/tests/baselines/reference/inheritanceStaticFuncOverridingProperty.js
@@ -13,8 +13,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticFuncOverridingPropertyOfFuncType.js b/tests/baselines/reference/inheritanceStaticFuncOverridingPropertyOfFuncType.js
index f9513f68585..979f0c36359 100644
--- a/tests/baselines/reference/inheritanceStaticFuncOverridingPropertyOfFuncType.js
+++ b/tests/baselines/reference/inheritanceStaticFuncOverridingPropertyOfFuncType.js
@@ -13,8 +13,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticFunctionOverridingInstanceProperty.js b/tests/baselines/reference/inheritanceStaticFunctionOverridingInstanceProperty.js
index f64615e8a7c..5c6c0e06a6f 100644
--- a/tests/baselines/reference/inheritanceStaticFunctionOverridingInstanceProperty.js
+++ b/tests/baselines/reference/inheritanceStaticFunctionOverridingInstanceProperty.js
@@ -13,8 +13,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticMembersCompatible.js b/tests/baselines/reference/inheritanceStaticMembersCompatible.js
index f1e288c57f5..014d3276189 100644
--- a/tests/baselines/reference/inheritanceStaticMembersCompatible.js
+++ b/tests/baselines/reference/inheritanceStaticMembersCompatible.js
@@ -11,8 +11,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticMembersIncompatible.js b/tests/baselines/reference/inheritanceStaticMembersIncompatible.js
index 66ad8612538..a1728dc6dcb 100644
--- a/tests/baselines/reference/inheritanceStaticMembersIncompatible.js
+++ b/tests/baselines/reference/inheritanceStaticMembersIncompatible.js
@@ -11,8 +11,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticPropertyOverridingAccessor.js b/tests/baselines/reference/inheritanceStaticPropertyOverridingAccessor.js
index 310f2127e7e..b81b6cd1d78 100644
--- a/tests/baselines/reference/inheritanceStaticPropertyOverridingAccessor.js
+++ b/tests/baselines/reference/inheritanceStaticPropertyOverridingAccessor.js
@@ -15,8 +15,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticPropertyOverridingMethod.js b/tests/baselines/reference/inheritanceStaticPropertyOverridingMethod.js
index 3e8a444d772..9afa969af65 100644
--- a/tests/baselines/reference/inheritanceStaticPropertyOverridingMethod.js
+++ b/tests/baselines/reference/inheritanceStaticPropertyOverridingMethod.js
@@ -13,8 +13,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritanceStaticPropertyOverridingProperty.js b/tests/baselines/reference/inheritanceStaticPropertyOverridingProperty.js
index 088cfa9b1f9..fcecca62774 100644
--- a/tests/baselines/reference/inheritanceStaticPropertyOverridingProperty.js
+++ b/tests/baselines/reference/inheritanceStaticPropertyOverridingProperty.js
@@ -11,8 +11,7 @@ class b extends a {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = (function () {
     function a() {
diff --git a/tests/baselines/reference/inheritedConstructorWithRestParams.js b/tests/baselines/reference/inheritedConstructorWithRestParams.js
index 45f4fe72535..a0bb2ed8dc1 100644
--- a/tests/baselines/reference/inheritedConstructorWithRestParams.js
+++ b/tests/baselines/reference/inheritedConstructorWithRestParams.js
@@ -18,8 +18,7 @@ new Derived(3);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/inheritedConstructorWithRestParams2.js b/tests/baselines/reference/inheritedConstructorWithRestParams2.js
index eeb0413d1ec..9b87465233c 100644
--- a/tests/baselines/reference/inheritedConstructorWithRestParams2.js
+++ b/tests/baselines/reference/inheritedConstructorWithRestParams2.js
@@ -38,8 +38,7 @@ new Derived("", 3, "", "");
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var IBaseBase = (function () {
     function IBaseBase(x) {
diff --git a/tests/baselines/reference/inheritedModuleMembersForClodule.js b/tests/baselines/reference/inheritedModuleMembersForClodule.js
index 75a2f13fed7..50f41af2c09 100644
--- a/tests/baselines/reference/inheritedModuleMembersForClodule.js
+++ b/tests/baselines/reference/inheritedModuleMembersForClodule.js
@@ -25,8 +25,7 @@ class E extends D {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/instancePropertiesInheritedIntoClassType.js b/tests/baselines/reference/instancePropertiesInheritedIntoClassType.js
index 9e8e6d26b31..548cb77b878 100644
--- a/tests/baselines/reference/instancePropertiesInheritedIntoClassType.js
+++ b/tests/baselines/reference/instancePropertiesInheritedIntoClassType.js
@@ -46,8 +46,7 @@ module Generic {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var NonGeneric;
 (function (NonGeneric) {
diff --git a/tests/baselines/reference/instanceSubtypeCheck2.js b/tests/baselines/reference/instanceSubtypeCheck2.js
index e02a2b2afad..59043b29b4e 100644
--- a/tests/baselines/reference/instanceSubtypeCheck2.js
+++ b/tests/baselines/reference/instanceSubtypeCheck2.js
@@ -11,8 +11,7 @@ class C2<T> extends C1<T> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function () {
     function C1() {
diff --git a/tests/baselines/reference/instantiatedReturnTypeContravariance.js b/tests/baselines/reference/instantiatedReturnTypeContravariance.js
index 678f324797f..2484816fe33 100644
--- a/tests/baselines/reference/instantiatedReturnTypeContravariance.js
+++ b/tests/baselines/reference/instantiatedReturnTypeContravariance.js
@@ -34,8 +34,7 @@ return null;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var c = (function () {
     function c() {
diff --git a/tests/baselines/reference/interfaceExtendsClass1.js b/tests/baselines/reference/interfaceExtendsClass1.js
index 5e72b36ef30..2fbe01bdf67 100644
--- a/tests/baselines/reference/interfaceExtendsClass1.js
+++ b/tests/baselines/reference/interfaceExtendsClass1.js
@@ -22,8 +22,7 @@ class Location {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Control = (function () {
     function Control() {
diff --git a/tests/baselines/reference/interfaceExtendsClassWithPrivate1.js b/tests/baselines/reference/interfaceExtendsClassWithPrivate1.js
index dac502b9ca3..9a6e92c3e2b 100644
--- a/tests/baselines/reference/interfaceExtendsClassWithPrivate1.js
+++ b/tests/baselines/reference/interfaceExtendsClassWithPrivate1.js
@@ -31,8 +31,7 @@ d = c; // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/interfaceExtendsClassWithPrivate2.js b/tests/baselines/reference/interfaceExtendsClassWithPrivate2.js
index c6a11c1d3ab..44738036f96 100644
--- a/tests/baselines/reference/interfaceExtendsClassWithPrivate2.js
+++ b/tests/baselines/reference/interfaceExtendsClassWithPrivate2.js
@@ -27,8 +27,7 @@ class D2 extends C implements I { // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/interfaceImplementation8.js b/tests/baselines/reference/interfaceImplementation8.js
index 64b4c453829..cb6eaa12450 100644
--- a/tests/baselines/reference/interfaceImplementation8.js
+++ b/tests/baselines/reference/interfaceImplementation8.js
@@ -44,8 +44,7 @@ class C8 extends C7 implements i2{
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function () {
     function C1() {
diff --git a/tests/baselines/reference/invalidModuleWithStatementsOfEveryKind.js b/tests/baselines/reference/invalidModuleWithStatementsOfEveryKind.js
index 4b3ab1b6d88..0b662b56f06 100644
--- a/tests/baselines/reference/invalidModuleWithStatementsOfEveryKind.js
+++ b/tests/baselines/reference/invalidModuleWithStatementsOfEveryKind.js
@@ -83,8 +83,7 @@ module YYY4 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Y;
 (function (Y) {
diff --git a/tests/baselines/reference/invalidMultipleVariableDeclarations.js b/tests/baselines/reference/invalidMultipleVariableDeclarations.js
index 31d0e44c918..b239a3dc1dd 100644
--- a/tests/baselines/reference/invalidMultipleVariableDeclarations.js
+++ b/tests/baselines/reference/invalidMultipleVariableDeclarations.js
@@ -57,8 +57,7 @@ var m = M.A;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/invalidReturnStatements.js b/tests/baselines/reference/invalidReturnStatements.js
index 50977334f4c..5fbe8c4dc37 100644
--- a/tests/baselines/reference/invalidReturnStatements.js
+++ b/tests/baselines/reference/invalidReturnStatements.js
@@ -24,8 +24,7 @@ function fn11(): D { return new C(); }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // all the following should be error
 function fn1() { }
diff --git a/tests/baselines/reference/isolatedModulesImportExportElision.js b/tests/baselines/reference/isolatedModulesImportExportElision.js
index ca3eee0ac2b..8cb65747e6f 100644
--- a/tests/baselines/reference/isolatedModulesImportExportElision.js
+++ b/tests/baselines/reference/isolatedModulesImportExportElision.js
@@ -17,8 +17,7 @@ export var z = x;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var module_1 = require("module");
 var module_2 = require("module");
diff --git a/tests/baselines/reference/lambdaArgCrash.js b/tests/baselines/reference/lambdaArgCrash.js
index 0f71ae803d6..5616b5d525f 100644
--- a/tests/baselines/reference/lambdaArgCrash.js
+++ b/tests/baselines/reference/lambdaArgCrash.js
@@ -38,8 +38,7 @@ class ItemSetEvent extends Event {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Event = (function () {
     function Event() {
diff --git a/tests/baselines/reference/lift.js b/tests/baselines/reference/lift.js
index eaaf94e7024..a832b34641d 100644
--- a/tests/baselines/reference/lift.js
+++ b/tests/baselines/reference/lift.js
@@ -21,8 +21,7 @@ class C extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var B = (function () {
     function B(y) {
diff --git a/tests/baselines/reference/localTypes1.js b/tests/baselines/reference/localTypes1.js
index 09fa9c04f3c..00c65db2c96 100644
--- a/tests/baselines/reference/localTypes1.js
+++ b/tests/baselines/reference/localTypes1.js
@@ -145,8 +145,7 @@ function f6() {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function f1() {
     var E;
diff --git a/tests/baselines/reference/m7Bugs.js b/tests/baselines/reference/m7Bugs.js
index 72829316fb8..86b5aa96c77 100644
--- a/tests/baselines/reference/m7Bugs.js
+++ b/tests/baselines/reference/m7Bugs.js
@@ -30,8 +30,7 @@ var y3: C1 = <C1> {};
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var s = ({});
 var x = {};
diff --git a/tests/baselines/reference/mergedInterfacesWithInheritedPrivates2.js b/tests/baselines/reference/mergedInterfacesWithInheritedPrivates2.js
index 389bbfa63dd..26cd3c8bf7c 100644
--- a/tests/baselines/reference/mergedInterfacesWithInheritedPrivates2.js
+++ b/tests/baselines/reference/mergedInterfacesWithInheritedPrivates2.js
@@ -35,8 +35,7 @@ var r2 = a.w; // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/mergedInterfacesWithInheritedPrivates3.js b/tests/baselines/reference/mergedInterfacesWithInheritedPrivates3.js
index d088aab3d3c..530595d54f6 100644
--- a/tests/baselines/reference/mergedInterfacesWithInheritedPrivates3.js
+++ b/tests/baselines/reference/mergedInterfacesWithInheritedPrivates3.js
@@ -42,8 +42,7 @@ module M {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/moduleAsBaseType.js b/tests/baselines/reference/moduleAsBaseType.js
index c2246be8795..7e2af06480d 100644
--- a/tests/baselines/reference/moduleAsBaseType.js
+++ b/tests/baselines/reference/moduleAsBaseType.js
@@ -8,8 +8,7 @@ class C2 implements M { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/moduleImportedForTypeArgumentPosition.js b/tests/baselines/reference/moduleImportedForTypeArgumentPosition.js
index e8e08eed26c..9b7449b95ca 100644
--- a/tests/baselines/reference/moduleImportedForTypeArgumentPosition.js
+++ b/tests/baselines/reference/moduleImportedForTypeArgumentPosition.js
@@ -18,8 +18,7 @@ define(["require", "exports"], function (require, exports) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 define(["require", "exports"], function (require, exports) {
     var C1 = (function () {
diff --git a/tests/baselines/reference/moduleWithStatementsOfEveryKind.js b/tests/baselines/reference/moduleWithStatementsOfEveryKind.js
index 6c0f625f986..aeffc8d6e5b 100644
--- a/tests/baselines/reference/moduleWithStatementsOfEveryKind.js
+++ b/tests/baselines/reference/moduleWithStatementsOfEveryKind.js
@@ -62,8 +62,7 @@ module Y {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A;
 (function (A_1) {
diff --git a/tests/baselines/reference/multipleInheritance.js b/tests/baselines/reference/multipleInheritance.js
index ea4a7156df9..901838b584b 100644
--- a/tests/baselines/reference/multipleInheritance.js
+++ b/tests/baselines/reference/multipleInheritance.js
@@ -42,8 +42,7 @@ class Baad extends Good {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var B1 = (function () {
     function B1() {
diff --git a/tests/baselines/reference/mutuallyRecursiveGenericBaseTypes2.js b/tests/baselines/reference/mutuallyRecursiveGenericBaseTypes2.js
index 9b3d6f31291..09f4be0c4e9 100644
--- a/tests/baselines/reference/mutuallyRecursiveGenericBaseTypes2.js
+++ b/tests/baselines/reference/mutuallyRecursiveGenericBaseTypes2.js
@@ -14,8 +14,7 @@ var test = new foo<string>();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var foo = (function () {
     function foo() {
diff --git a/tests/baselines/reference/namespacesDeclaration.js b/tests/baselines/reference/namespacesDeclaration.js
new file mode 100644
index 00000000000..7c7cfa84af0
--- /dev/null
+++ b/tests/baselines/reference/namespacesDeclaration.js
@@ -0,0 +1,22 @@
+//// [namespacesDeclaration.ts]
+
+module M {
+   export namespace N {
+      export module M2 {
+         export interface I {}
+      }
+   }
+}
+
+//// [namespacesDeclaration.js]
+
+
+//// [namespacesDeclaration.d.ts]
+declare module M {
+    namespace N {
+        module M2 {
+            interface I {
+            }
+        }
+    }
+}
diff --git a/tests/baselines/reference/namespacesDeclaration.symbols b/tests/baselines/reference/namespacesDeclaration.symbols
new file mode 100644
index 00000000000..1706f212f34
--- /dev/null
+++ b/tests/baselines/reference/namespacesDeclaration.symbols
@@ -0,0 +1,16 @@
+=== tests/cases/compiler/namespacesDeclaration.ts ===
+
+module M {
+>M : Symbol(M, Decl(namespacesDeclaration.ts, 0, 0))
+
+   export namespace N {
+>N : Symbol(N, Decl(namespacesDeclaration.ts, 1, 10))
+
+      export module M2 {
+>M2 : Symbol(M2, Decl(namespacesDeclaration.ts, 2, 23))
+
+         export interface I {}
+>I : Symbol(I, Decl(namespacesDeclaration.ts, 3, 24))
+      }
+   }
+}
diff --git a/tests/baselines/reference/namespacesDeclaration.types b/tests/baselines/reference/namespacesDeclaration.types
new file mode 100644
index 00000000000..944098097fc
--- /dev/null
+++ b/tests/baselines/reference/namespacesDeclaration.types
@@ -0,0 +1,16 @@
+=== tests/cases/compiler/namespacesDeclaration.ts ===
+
+module M {
+>M : any
+
+   export namespace N {
+>N : any
+
+      export module M2 {
+>M2 : any
+
+         export interface I {}
+>I : I
+      }
+   }
+}
diff --git a/tests/baselines/reference/nonGenericClassExtendingGenericClassWithAny.js b/tests/baselines/reference/nonGenericClassExtendingGenericClassWithAny.js
index b687162c154..7cdb702d6ff 100644
--- a/tests/baselines/reference/nonGenericClassExtendingGenericClassWithAny.js
+++ b/tests/baselines/reference/nonGenericClassExtendingGenericClassWithAny.js
@@ -9,8 +9,7 @@ class Bar extends Foo<any> { } // Valid
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations2.js b/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations2.js
index fe1e4768672..ade000d50ba 100644
--- a/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations2.js
+++ b/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations2.js
@@ -50,8 +50,7 @@ var b: { [x: number]: A } = {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/numericIndexerConstraint3.js b/tests/baselines/reference/numericIndexerConstraint3.js
index 724db29f557..dc3b6024eee 100644
--- a/tests/baselines/reference/numericIndexerConstraint3.js
+++ b/tests/baselines/reference/numericIndexerConstraint3.js
@@ -16,8 +16,7 @@ class C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/numericIndexerConstraint4.js b/tests/baselines/reference/numericIndexerConstraint4.js
index 404a9394bf7..7509c64eac8 100644
--- a/tests/baselines/reference/numericIndexerConstraint4.js
+++ b/tests/baselines/reference/numericIndexerConstraint4.js
@@ -15,8 +15,7 @@ var x: {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/numericIndexerTyping2.js b/tests/baselines/reference/numericIndexerTyping2.js
index c5e91e9dfc0..2e3ba2ce74c 100644
--- a/tests/baselines/reference/numericIndexerTyping2.js
+++ b/tests/baselines/reference/numericIndexerTyping2.js
@@ -16,8 +16,7 @@ var r2: string = i2[1]; // error: numeric indexer returns the type of the string
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var I = (function () {
     function I() {
diff --git a/tests/baselines/reference/objectCreationOfElementAccessExpression.js b/tests/baselines/reference/objectCreationOfElementAccessExpression.js
index 45d56a1d716..05457a559e9 100644
--- a/tests/baselines/reference/objectCreationOfElementAccessExpression.js
+++ b/tests/baselines/reference/objectCreationOfElementAccessExpression.js
@@ -59,8 +59,7 @@ var foods2: MonsterFood[] = new PetFood[new IceCream('Mint chocolate chip') , Co
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Food = (function () {
     function Food(name) {
diff --git a/tests/baselines/reference/objectTypeHidingMembersOfExtendedObject.js b/tests/baselines/reference/objectTypeHidingMembersOfExtendedObject.js
index 339f6b23f6a..5d30e0faecf 100644
--- a/tests/baselines/reference/objectTypeHidingMembersOfExtendedObject.js
+++ b/tests/baselines/reference/objectTypeHidingMembersOfExtendedObject.js
@@ -58,8 +58,7 @@ var r4: void = b.valueOf();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers1.js b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers1.js
index 8f6d1706e40..e0f626ae083 100644
--- a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers1.js
+++ b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers1.js
@@ -127,8 +127,7 @@ function foo16(x: any) { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers2.js b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers2.js
index 8f5b6449a88..f0417a7ca23 100644
--- a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers2.js
+++ b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers2.js
@@ -130,8 +130,7 @@ function foo16(x: any) { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers3.js b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers3.js
index 2fc8c0c946d..e1473790553 100644
--- a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers3.js
+++ b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers3.js
@@ -127,8 +127,7 @@ function foo16(x: any) { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/objectTypesIdentityWithPrivates.js b/tests/baselines/reference/objectTypesIdentityWithPrivates.js
index a68eba8c6a2..bf4f80da15a 100644
--- a/tests/baselines/reference/objectTypesIdentityWithPrivates.js
+++ b/tests/baselines/reference/objectTypesIdentityWithPrivates.js
@@ -125,8 +125,7 @@ function foo16(x: any) { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/objectTypesIdentityWithPrivates2.js b/tests/baselines/reference/objectTypesIdentityWithPrivates2.js
index 92aac37ecdb..c8cd12cff30 100644
--- a/tests/baselines/reference/objectTypesIdentityWithPrivates2.js
+++ b/tests/baselines/reference/objectTypesIdentityWithPrivates2.js
@@ -43,8 +43,7 @@ function foo6(x: any): any { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/objectTypesIdentityWithPrivates3.js b/tests/baselines/reference/objectTypesIdentityWithPrivates3.js
index c202f684895..a812a1fc4bd 100644
--- a/tests/baselines/reference/objectTypesIdentityWithPrivates3.js
+++ b/tests/baselines/reference/objectTypesIdentityWithPrivates3.js
@@ -29,8 +29,7 @@ var c3: C3<T2>;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function () {
     function C1() {
diff --git a/tests/baselines/reference/objectTypesIdentityWithStringIndexers.js b/tests/baselines/reference/objectTypesIdentityWithStringIndexers.js
index 98693b4e6ee..9cf9e99cb4b 100644
--- a/tests/baselines/reference/objectTypesIdentityWithStringIndexers.js
+++ b/tests/baselines/reference/objectTypesIdentityWithStringIndexers.js
@@ -127,8 +127,7 @@ function foo16(x: any) { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/objectTypesIdentityWithStringIndexers2.js b/tests/baselines/reference/objectTypesIdentityWithStringIndexers2.js
index 7e9abbad7e6..84f3d04e7bf 100644
--- a/tests/baselines/reference/objectTypesIdentityWithStringIndexers2.js
+++ b/tests/baselines/reference/objectTypesIdentityWithStringIndexers2.js
@@ -130,8 +130,7 @@ function foo16(x: any) { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/optionalConstructorArgInSuper.js b/tests/baselines/reference/optionalConstructorArgInSuper.js
index 2ac23c39be5..e8b65ea5119 100644
--- a/tests/baselines/reference/optionalConstructorArgInSuper.js
+++ b/tests/baselines/reference/optionalConstructorArgInSuper.js
@@ -14,8 +14,7 @@ d2.foo();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(opt) {
diff --git a/tests/baselines/reference/optionalParamArgsTest.js b/tests/baselines/reference/optionalParamArgsTest.js
index 7538397566a..414f474598d 100644
--- a/tests/baselines/reference/optionalParamArgsTest.js
+++ b/tests/baselines/reference/optionalParamArgsTest.js
@@ -129,8 +129,7 @@ fnOpt2(1, [2, 3], [1], true);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // test basic configurations
 var C1 = (function () {
diff --git a/tests/baselines/reference/optionalParamInOverride.js b/tests/baselines/reference/optionalParamInOverride.js
index aa76f41644c..4a72953bdad 100644
--- a/tests/baselines/reference/optionalParamInOverride.js
+++ b/tests/baselines/reference/optionalParamInOverride.js
@@ -11,8 +11,7 @@ class Y extends Z {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Z = (function () {
     function Z() {
diff --git a/tests/baselines/reference/overload1.js b/tests/baselines/reference/overload1.js
index b308c0e8d83..af3aebde4ee 100644
--- a/tests/baselines/reference/overload1.js
+++ b/tests/baselines/reference/overload1.js
@@ -43,8 +43,7 @@ var v=x.g;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var O;
 (function (O) {
diff --git a/tests/baselines/reference/overloadOnConstConstraintChecks1.js b/tests/baselines/reference/overloadOnConstConstraintChecks1.js
index 4588bef017b..67aa365ee39 100644
--- a/tests/baselines/reference/overloadOnConstConstraintChecks1.js
+++ b/tests/baselines/reference/overloadOnConstConstraintChecks1.js
@@ -26,8 +26,7 @@ class D implements MyDoc {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/overloadOnConstConstraintChecks2.js b/tests/baselines/reference/overloadOnConstConstraintChecks2.js
index 709f7808ac1..353680bb92e 100644
--- a/tests/baselines/reference/overloadOnConstConstraintChecks2.js
+++ b/tests/baselines/reference/overloadOnConstConstraintChecks2.js
@@ -15,8 +15,7 @@ function foo(name: any): A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/overloadOnConstConstraintChecks3.js b/tests/baselines/reference/overloadOnConstConstraintChecks3.js
index 7104c441938..2debaa589f5 100644
--- a/tests/baselines/reference/overloadOnConstConstraintChecks3.js
+++ b/tests/baselines/reference/overloadOnConstConstraintChecks3.js
@@ -16,8 +16,7 @@ function foo(name: any): A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/overloadOnConstConstraintChecks4.js b/tests/baselines/reference/overloadOnConstConstraintChecks4.js
index 4483b42a941..17ec3779620 100644
--- a/tests/baselines/reference/overloadOnConstConstraintChecks4.js
+++ b/tests/baselines/reference/overloadOnConstConstraintChecks4.js
@@ -17,8 +17,7 @@ function foo(name: any): Z {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Z = (function () {
     function Z() {
diff --git a/tests/baselines/reference/overloadOnConstantsInvalidOverload1.js b/tests/baselines/reference/overloadOnConstantsInvalidOverload1.js
index efcad011ab5..a8dfcde9ada 100644
--- a/tests/baselines/reference/overloadOnConstantsInvalidOverload1.js
+++ b/tests/baselines/reference/overloadOnConstantsInvalidOverload1.js
@@ -15,8 +15,7 @@ foo("HI");
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/overloadResolution.js b/tests/baselines/reference/overloadResolution.js
index d234ea4a69a..287c5ccdb8e 100644
--- a/tests/baselines/reference/overloadResolution.js
+++ b/tests/baselines/reference/overloadResolution.js
@@ -98,8 +98,7 @@ var s = fn5((n) => n.substr(0));
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var SomeBase = (function () {
     function SomeBase() {
diff --git a/tests/baselines/reference/overloadResolutionClassConstructors.js b/tests/baselines/reference/overloadResolutionClassConstructors.js
index fc7dbd9cebe..14306b7873b 100644
--- a/tests/baselines/reference/overloadResolutionClassConstructors.js
+++ b/tests/baselines/reference/overloadResolutionClassConstructors.js
@@ -105,8 +105,7 @@ new fn5((n) => n.blah); // Error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var SomeBase = (function () {
     function SomeBase() {
diff --git a/tests/baselines/reference/overloadResolutionConstructors.js b/tests/baselines/reference/overloadResolutionConstructors.js
index b3c2b2ef764..788e6362f86 100644
--- a/tests/baselines/reference/overloadResolutionConstructors.js
+++ b/tests/baselines/reference/overloadResolutionConstructors.js
@@ -106,8 +106,7 @@ var s = new fn5((n) => n.substr(0));
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var SomeBase = (function () {
     function SomeBase() {
diff --git a/tests/baselines/reference/overloadingOnConstants1.js b/tests/baselines/reference/overloadingOnConstants1.js
index 4274841d60f..bd08f70498d 100644
--- a/tests/baselines/reference/overloadingOnConstants1.js
+++ b/tests/baselines/reference/overloadingOnConstants1.js
@@ -29,8 +29,7 @@ var htmlSpanElement2: Derived1 = d2.createElement("span");
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/overloadingOnConstants2.js b/tests/baselines/reference/overloadingOnConstants2.js
index 2414ec4eab2..eaec0054f66 100644
--- a/tests/baselines/reference/overloadingOnConstants2.js
+++ b/tests/baselines/reference/overloadingOnConstants2.js
@@ -31,8 +31,7 @@ var f: C = bar("um", []); // C
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/overridingPrivateStaticMembers.js b/tests/baselines/reference/overridingPrivateStaticMembers.js
index 56ecfec66c0..a155bb1b830 100644
--- a/tests/baselines/reference/overridingPrivateStaticMembers.js
+++ b/tests/baselines/reference/overridingPrivateStaticMembers.js
@@ -11,8 +11,7 @@ class Derived2 extends Base2 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base2 = (function () {
     function Base2() {
diff --git a/tests/baselines/reference/parseErrorInHeritageClause1.js b/tests/baselines/reference/parseErrorInHeritageClause1.js
index 66facdeadf0..b6640b64257 100644
--- a/tests/baselines/reference/parseErrorInHeritageClause1.js
+++ b/tests/baselines/reference/parseErrorInHeritageClause1.js
@@ -6,8 +6,7 @@ class C extends A # {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/parser509630.js b/tests/baselines/reference/parser509630.js
index 20e00ea01ed..6862eef4a93 100644
--- a/tests/baselines/reference/parser509630.js
+++ b/tests/baselines/reference/parser509630.js
@@ -10,8 +10,7 @@ class Any extends Type {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Type = (function () {
     function Type() {
diff --git a/tests/baselines/reference/parserAstSpans1.js b/tests/baselines/reference/parserAstSpans1.js
index ec88d11b0c9..5de3cb8f9f1 100644
--- a/tests/baselines/reference/parserAstSpans1.js
+++ b/tests/baselines/reference/parserAstSpans1.js
@@ -223,8 +223,7 @@ class c6 extends c5 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var c1 = (function () {
     function c1() {
diff --git a/tests/baselines/reference/parserClassDeclaration1.js b/tests/baselines/reference/parserClassDeclaration1.js
index 9ef865adb75..f430b8e644a 100644
--- a/tests/baselines/reference/parserClassDeclaration1.js
+++ b/tests/baselines/reference/parserClassDeclaration1.js
@@ -6,8 +6,7 @@ class C extends A extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/parserClassDeclaration3.js b/tests/baselines/reference/parserClassDeclaration3.js
index 644c4fcb54a..8ea681a668f 100644
--- a/tests/baselines/reference/parserClassDeclaration3.js
+++ b/tests/baselines/reference/parserClassDeclaration3.js
@@ -6,8 +6,7 @@ class C implements A extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/parserClassDeclaration4.js b/tests/baselines/reference/parserClassDeclaration4.js
index d7cd9ca6cac..2bbbd134ed4 100644
--- a/tests/baselines/reference/parserClassDeclaration4.js
+++ b/tests/baselines/reference/parserClassDeclaration4.js
@@ -6,8 +6,7 @@ class C extends A implements B extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/parserClassDeclaration5.js b/tests/baselines/reference/parserClassDeclaration5.js
index 4f75eb96668..146cbda9563 100644
--- a/tests/baselines/reference/parserClassDeclaration5.js
+++ b/tests/baselines/reference/parserClassDeclaration5.js
@@ -6,8 +6,7 @@ class C extends A implements B implements C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/parserClassDeclaration6.js b/tests/baselines/reference/parserClassDeclaration6.js
index a653a7e4042..0f65ad53f07 100644
--- a/tests/baselines/reference/parserClassDeclaration6.js
+++ b/tests/baselines/reference/parserClassDeclaration6.js
@@ -6,8 +6,7 @@ class C extends A, B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause2.js b/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause2.js
index 43ebfa2bb0e..3c2f96f54fd 100644
--- a/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause2.js
+++ b/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause2.js
@@ -6,8 +6,7 @@ class C extends A, {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause4.js b/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause4.js
index 732508b8d85..594c4575eab 100644
--- a/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause4.js
+++ b/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause4.js
@@ -6,8 +6,7 @@ class C extends A implements {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause5.js b/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause5.js
index 58f4f4631dc..3d2447e0b8c 100644
--- a/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause5.js
+++ b/tests/baselines/reference/parserErrorRecovery_ExtendsOrImplementsClause5.js
@@ -6,8 +6,7 @@ class C extends A, implements B, {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/parserGenericsInTypeContexts1.js b/tests/baselines/reference/parserGenericsInTypeContexts1.js
index 5c2369e61c7..9cea884bcfb 100644
--- a/tests/baselines/reference/parserGenericsInTypeContexts1.js
+++ b/tests/baselines/reference/parserGenericsInTypeContexts1.js
@@ -21,8 +21,7 @@ function f2(): F<T> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/parserGenericsInTypeContexts2.js b/tests/baselines/reference/parserGenericsInTypeContexts2.js
index 487038e1959..b5e5e010d56 100644
--- a/tests/baselines/reference/parserGenericsInTypeContexts2.js
+++ b/tests/baselines/reference/parserGenericsInTypeContexts2.js
@@ -21,8 +21,7 @@ function f2(): F<X<T>, Y<Z<T>>> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/parserRealSource10.js b/tests/baselines/reference/parserRealSource10.js
index 4c241abba0e..f184db9173c 100644
--- a/tests/baselines/reference/parserRealSource10.js
+++ b/tests/baselines/reference/parserRealSource10.js
@@ -461,8 +461,7 @@ module TypeScript {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 ///<reference path='typescript.ts' />
 var TypeScript;
diff --git a/tests/baselines/reference/parserRealSource11.js b/tests/baselines/reference/parserRealSource11.js
index c6a08062820..4091eb290d1 100644
--- a/tests/baselines/reference/parserRealSource11.js
+++ b/tests/baselines/reference/parserRealSource11.js
@@ -2370,8 +2370,7 @@ module TypeScript {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 ///<reference path='typescript.ts' />
 var TypeScript;
diff --git a/tests/baselines/reference/parserharness.js b/tests/baselines/reference/parserharness.js
index 4e22c804ab6..296aae05fad 100644
--- a/tests/baselines/reference/parserharness.js
+++ b/tests/baselines/reference/parserharness.js
@@ -2099,8 +2099,7 @@ module Harness {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 ///<reference path='..\compiler\io.ts'/>
 ///<reference path='..\compiler\typescript.ts'/>
diff --git a/tests/baselines/reference/primitiveMembers.js b/tests/baselines/reference/primitiveMembers.js
index a49d6f7ee1c..60ae4b79dec 100644
--- a/tests/baselines/reference/primitiveMembers.js
+++ b/tests/baselines/reference/primitiveMembers.js
@@ -35,8 +35,7 @@ class foo extends baz { public bar(){ return undefined}; }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var x = 5;
 var r = /yo/;
diff --git a/tests/baselines/reference/privacyClass.js b/tests/baselines/reference/privacyClass.js
index 4d6d0a72e4a..f632ea8b26f 100644
--- a/tests/baselines/reference/privacyClass.js
+++ b/tests/baselines/reference/privacyClass.js
@@ -131,8 +131,7 @@ export class glo_C12_public extends glo_c_private implements  glo_i_private, glo
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var m1;
 (function (m1) {
diff --git a/tests/baselines/reference/privacyClassExtendsClauseDeclFile.js b/tests/baselines/reference/privacyClassExtendsClauseDeclFile.js
index 044c30f3797..a3ddd387883 100644
--- a/tests/baselines/reference/privacyClassExtendsClauseDeclFile.js
+++ b/tests/baselines/reference/privacyClassExtendsClauseDeclFile.js
@@ -101,8 +101,7 @@ class publicClassExtendingPublicClassInGlobal extends publicClassInGlobal {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var publicModule;
 (function (publicModule) {
@@ -288,8 +287,7 @@ exports.publicClassExtendingFromPrivateModuleClass = publicClassExtendingFromPri
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var publicModuleInGlobal;
 (function (publicModuleInGlobal) {
diff --git a/tests/baselines/reference/privacyGloClass.js b/tests/baselines/reference/privacyGloClass.js
index 58877eae167..01eff312739 100644
--- a/tests/baselines/reference/privacyGloClass.js
+++ b/tests/baselines/reference/privacyGloClass.js
@@ -64,8 +64,7 @@ class glo_C11_public extends glo_c_public implements glo_i_public {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var m1;
 (function (m1) {
diff --git a/tests/baselines/reference/privateAccessInSubclass1.js b/tests/baselines/reference/privateAccessInSubclass1.js
index 7004a535952..b22af20af37 100644
--- a/tests/baselines/reference/privateAccessInSubclass1.js
+++ b/tests/baselines/reference/privateAccessInSubclass1.js
@@ -13,8 +13,7 @@ class D extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/privateInstanceMemberAccessibility.js b/tests/baselines/reference/privateInstanceMemberAccessibility.js
index 4158ef6a8f7..ac2f44ee5d9 100644
--- a/tests/baselines/reference/privateInstanceMemberAccessibility.js
+++ b/tests/baselines/reference/privateInstanceMemberAccessibility.js
@@ -17,8 +17,7 @@ class Derived extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/privateStaticMemberAccessibility.js b/tests/baselines/reference/privateStaticMemberAccessibility.js
index 013c606f829..0b9be3b69ff 100644
--- a/tests/baselines/reference/privateStaticMemberAccessibility.js
+++ b/tests/baselines/reference/privateStaticMemberAccessibility.js
@@ -12,8 +12,7 @@ class Derived extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/privateStaticNotAccessibleInClodule2.js b/tests/baselines/reference/privateStaticNotAccessibleInClodule2.js
index 3db3a636c7d..b67ca77dc26 100644
--- a/tests/baselines/reference/privateStaticNotAccessibleInClodule2.js
+++ b/tests/baselines/reference/privateStaticNotAccessibleInClodule2.js
@@ -19,8 +19,7 @@ module D {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/amd/testGlo.js b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/amd/testGlo.js
index 1ce3452dbed..bab996e07a4 100644
--- a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/amd/testGlo.js
+++ b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/amd/testGlo.js
@@ -1,8 +1,7 @@
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var m2;
 (function (m2) {
diff --git a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/node/testGlo.js b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/node/testGlo.js
index 1ce3452dbed..bab996e07a4 100644
--- a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/node/testGlo.js
+++ b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/node/testGlo.js
@@ -1,8 +1,7 @@
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var m2;
 (function (m2) {
diff --git a/tests/baselines/reference/project/prologueEmit/amd/out.js b/tests/baselines/reference/project/prologueEmit/amd/out.js
index e621c38f984..fb0ca5dfac0 100644
--- a/tests/baselines/reference/project/prologueEmit/amd/out.js
+++ b/tests/baselines/reference/project/prologueEmit/amd/out.js
@@ -4,8 +4,7 @@ var _this = this;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // class inheritance to ensure __extends is emitted
 var m;
diff --git a/tests/baselines/reference/project/prologueEmit/node/out.js b/tests/baselines/reference/project/prologueEmit/node/out.js
index e621c38f984..fb0ca5dfac0 100644
--- a/tests/baselines/reference/project/prologueEmit/node/out.js
+++ b/tests/baselines/reference/project/prologueEmit/node/out.js
@@ -4,8 +4,7 @@ var _this = this;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // class inheritance to ensure __extends is emitted
 var m;
diff --git a/tests/baselines/reference/project/quotesInFileAndDirectoryNames/amd/m'ain.js b/tests/baselines/reference/project/quotesInFileAndDirectoryNames/amd/m'ain.js
index b1f4dd64ef2..bdf2edefcb0 100644
--- a/tests/baselines/reference/project/quotesInFileAndDirectoryNames/amd/m'ain.js
+++ b/tests/baselines/reference/project/quotesInFileAndDirectoryNames/amd/m'ain.js
@@ -2,8 +2,7 @@
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var ClassC = (function (_super) {
     __extends(ClassC, _super);
diff --git a/tests/baselines/reference/project/quotesInFileAndDirectoryNames/node/m'ain.js b/tests/baselines/reference/project/quotesInFileAndDirectoryNames/node/m'ain.js
index b1f4dd64ef2..bdf2edefcb0 100644
--- a/tests/baselines/reference/project/quotesInFileAndDirectoryNames/node/m'ain.js
+++ b/tests/baselines/reference/project/quotesInFileAndDirectoryNames/node/m'ain.js
@@ -2,8 +2,7 @@
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var ClassC = (function (_super) {
     __extends(ClassC, _super);
diff --git a/tests/baselines/reference/propertiesAndIndexers.js b/tests/baselines/reference/propertiesAndIndexers.js
index f67a9d89249..b7a39ae2330 100644
--- a/tests/baselines/reference/propertiesAndIndexers.js
+++ b/tests/baselines/reference/propertiesAndIndexers.js
@@ -55,8 +55,7 @@ var c: {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var P = (function () {
     function P() {
diff --git a/tests/baselines/reference/propertyAccess.js b/tests/baselines/reference/propertyAccess.js
index 1e6ef5c1d6d..ed004b332cb 100644
--- a/tests/baselines/reference/propertyAccess.js
+++ b/tests/baselines/reference/propertyAccess.js
@@ -154,8 +154,7 @@ var x3: A;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints2.js b/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints2.js
index dc4c30d9165..35c279ba0ed 100644
--- a/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints2.js
+++ b/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints2.js
@@ -86,8 +86,7 @@ var r4 = b.foo(aB, aB); // no inferences for T so constraint isn't satisfied, er
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints3.js b/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints3.js
index 7e935609e36..24c3fc50501 100644
--- a/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints3.js
+++ b/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints3.js
@@ -61,8 +61,7 @@ var r4 = b.foo(new B()); // valid call to an invalid function
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints5.js b/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints5.js
index f871ce553b7..37b8240b9ac 100644
--- a/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints5.js
+++ b/tests/baselines/reference/propertyAccessOnTypeParameterWithConstraints5.js
@@ -48,8 +48,7 @@ var r4 = b.foo(new B()); // error after constraints above made illegal, doesn't
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass.js b/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass.js
index 45f001c65fb..ce7bc5d0b40 100644
--- a/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass.js
+++ b/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass.js
@@ -24,8 +24,7 @@ class C extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var B = (function () {
     function B() {
diff --git a/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass2.js b/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass2.js
index 10276f8ac85..e47e7e5a7d5 100644
--- a/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass2.js
+++ b/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass2.js
@@ -98,8 +98,7 @@ d4.x;                   // Error, neither within their declaring class nor class
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass3.js b/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass3.js
index 1a5b7489910..0140e61406c 100644
--- a/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass3.js
+++ b/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass3.js
@@ -17,8 +17,7 @@ class Derived extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/protectedInstanceMemberAccessibility.js b/tests/baselines/reference/protectedInstanceMemberAccessibility.js
index 7560c5c89ca..ff4ae952249 100644
--- a/tests/baselines/reference/protectedInstanceMemberAccessibility.js
+++ b/tests/baselines/reference/protectedInstanceMemberAccessibility.js
@@ -48,8 +48,7 @@ class C extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/protectedMembers.js b/tests/baselines/reference/protectedMembers.js
index 33b6e2ebde2..f86818b6e65 100644
--- a/tests/baselines/reference/protectedMembers.js
+++ b/tests/baselines/reference/protectedMembers.js
@@ -120,8 +120,7 @@ class B3 extends A3 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // Class with protected members
 var C1 = (function () {
diff --git a/tests/baselines/reference/protectedStaticClassPropertyAccessibleWithinSubclass.js b/tests/baselines/reference/protectedStaticClassPropertyAccessibleWithinSubclass.js
index 1bd102694d4..9edd43ad52e 100644
--- a/tests/baselines/reference/protectedStaticClassPropertyAccessibleWithinSubclass.js
+++ b/tests/baselines/reference/protectedStaticClassPropertyAccessibleWithinSubclass.js
@@ -47,8 +47,7 @@ Derived3.x;     // Error, neither within their declaring class nor classes deriv
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/protectedStaticClassPropertyAccessibleWithinSubclass2.js b/tests/baselines/reference/protectedStaticClassPropertyAccessibleWithinSubclass2.js
index c82c67b7003..5a8b07df371 100644
--- a/tests/baselines/reference/protectedStaticClassPropertyAccessibleWithinSubclass2.js
+++ b/tests/baselines/reference/protectedStaticClassPropertyAccessibleWithinSubclass2.js
@@ -25,8 +25,7 @@ class Derived2 extends Derived1 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/qualifiedName_entity-name-resolution-does-not-affect-class-heritage.errors.txt b/tests/baselines/reference/qualifiedName_entity-name-resolution-does-not-affect-class-heritage.errors.txt
index 3c67ff44fd3..e6929df9bae 100644
--- a/tests/baselines/reference/qualifiedName_entity-name-resolution-does-not-affect-class-heritage.errors.txt
+++ b/tests/baselines/reference/qualifiedName_entity-name-resolution-does-not-affect-class-heritage.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/qualifiedName_entity-name-resolution-does-not-affect-class-heritage.ts(5,20): error TS2507: Base expression is not of a constructor function type.
+tests/cases/compiler/qualifiedName_entity-name-resolution-does-not-affect-class-heritage.ts(5,20): error TS2507: Type 'number' is not a constructor function type.
 
 
 ==== tests/cases/compiler/qualifiedName_entity-name-resolution-does-not-affect-class-heritage.ts (1 errors) ====
@@ -8,5 +8,5 @@ tests/cases/compiler/qualifiedName_entity-name-resolution-does-not-affect-class-
     
     class Beta extends Alpha.x {
                        ~~~~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'number' is not a constructor function type.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/qualifiedName_entity-name-resolution-does-not-affect-class-heritage.js b/tests/baselines/reference/qualifiedName_entity-name-resolution-does-not-affect-class-heritage.js
index 8b071cb6b52..b0079c2f45b 100644
--- a/tests/baselines/reference/qualifiedName_entity-name-resolution-does-not-affect-class-heritage.js
+++ b/tests/baselines/reference/qualifiedName_entity-name-resolution-does-not-affect-class-heritage.js
@@ -10,8 +10,7 @@ class Beta extends Alpha.x {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Alpha;
 (function (Alpha) {
diff --git a/tests/baselines/reference/recursiveBaseCheck3.js b/tests/baselines/reference/recursiveBaseCheck3.js
index 6c1cd918779..aeb0d70240f 100644
--- a/tests/baselines/reference/recursiveBaseCheck3.js
+++ b/tests/baselines/reference/recursiveBaseCheck3.js
@@ -8,8 +8,7 @@ class C<T> extends A<T> { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function (_super) {
     __extends(A, _super);
diff --git a/tests/baselines/reference/recursiveBaseCheck4.js b/tests/baselines/reference/recursiveBaseCheck4.js
index 1abb6731263..2e4a745a703 100644
--- a/tests/baselines/reference/recursiveBaseCheck4.js
+++ b/tests/baselines/reference/recursiveBaseCheck4.js
@@ -6,8 +6,7 @@ class M<T> extends M<string> { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M = (function (_super) {
     __extends(M, _super);
diff --git a/tests/baselines/reference/recursiveBaseCheck6.js b/tests/baselines/reference/recursiveBaseCheck6.js
index 7fb9b444650..13b4944e96f 100644
--- a/tests/baselines/reference/recursiveBaseCheck6.js
+++ b/tests/baselines/reference/recursiveBaseCheck6.js
@@ -6,8 +6,7 @@ class S18<A> extends S18<{ S19: A; }>{ }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var S18 = (function (_super) {
     __extends(S18, _super);
diff --git a/tests/baselines/reference/recursiveBaseConstructorCreation1.js b/tests/baselines/reference/recursiveBaseConstructorCreation1.js
index d0fc83b30f2..d14a78ed908 100644
--- a/tests/baselines/reference/recursiveBaseConstructorCreation1.js
+++ b/tests/baselines/reference/recursiveBaseConstructorCreation1.js
@@ -10,8 +10,7 @@ var x = new C2(); // Valid
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function () {
     function C1() {
diff --git a/tests/baselines/reference/recursiveClassInstantiationsWithDefaultConstructors.js b/tests/baselines/reference/recursiveClassInstantiationsWithDefaultConstructors.js
index 214c543b836..224c13e7765 100644
--- a/tests/baselines/reference/recursiveClassInstantiationsWithDefaultConstructors.js
+++ b/tests/baselines/reference/recursiveClassInstantiationsWithDefaultConstructors.js
@@ -13,8 +13,7 @@ export class MemberNameArray extends MemberName {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var a = new TypeScript2.MemberNameArray();
 var TypeScript2;
diff --git a/tests/baselines/reference/recursiveClassReferenceTest.js b/tests/baselines/reference/recursiveClassReferenceTest.js
index e9339fec4df..0e884b94e8e 100644
--- a/tests/baselines/reference/recursiveClassReferenceTest.js
+++ b/tests/baselines/reference/recursiveClassReferenceTest.js
@@ -108,8 +108,7 @@ module Sample.Thing.Languages.PlainText {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Sample;
 (function (Sample) {
diff --git a/tests/baselines/reference/recursiveClassReferenceTest.js.map b/tests/baselines/reference/recursiveClassReferenceTest.js.map
index 5573bdd8de8..734906688fd 100644
--- a/tests/baselines/reference/recursiveClassReferenceTest.js.map
+++ b/tests/baselines/reference/recursiveClassReferenceTest.js.map
@@ -1,2 +1,2 @@
 //// [recursiveClassReferenceTest.js.map]
-{"version":3,"file":"recursiveClassReferenceTest.js","sourceRoot":"","sources":["recursiveClassReferenceTest.ts"],"names":["Sample","Sample.Actions","Sample.Actions.Thing","Sample.Actions.Thing.Find","Sample.Actions.Thing.Find.StartFindAction","Sample.Actions.Thing.Find.StartFindAction.constructor","Sample.Actions.Thing.Find.StartFindAction.getId","Sample.Actions.Thing.Find.StartFindAction.run","Sample.Thing","Sample.Thing.Widgets","Sample.Thing.Widgets.FindWidget","Sample.Thing.Widgets.FindWidget.constructor","Sample.Thing.Widgets.FindWidget.gar","Sample.Thing.Widgets.FindWidget.getDomNode","Sample.Thing.Widgets.FindWidget.destroy","AbstractMode","AbstractMode.constructor","AbstractMode.getInitialState","Sample.Thing.Languages","Sample.Thing.Languages.PlainText","Sample.Thing.Languages.PlainText.State","Sample.Thing.Languages.PlainText.State.constructor","Sample.Thing.Languages.PlainText.State.clone","Sample.Thing.Languages.PlainText.State.equals","Sample.Thing.Languages.PlainText.State.getMode","Sample.Thing.Languages.PlainText.Mode","Sample.Thing.Languages.PlainText.Mode.constructor","Sample.Thing.Languages.PlainText.Mode.getInitialState"],"mappings":"AAAA,iEAAiE;AACjE,0EAA0E;;;;;;;AA8B1E,IAAO,MAAM,CAUZ;AAVD,WAAO,MAAM;IAACA,IAAAA,OAAOA,CAUpBA;IAVaA,WAAAA,OAAOA;QAACC,IAAAA,KAAKA,CAU1BA;QAVqBA,WAAAA,OAAKA;YAACC,IAAAA,IAAIA,CAU/BA;YAV2BA,WAAAA,IAAIA,EAACA,CAACA;gBACjCC;oBAAAC;oBAQAC,CAACA;oBANOD,+BAAKA,GAAZA,cAAiBE,MAAMA,CAACA,IAAIA,CAACA,CAACA,CAACA;oBAExBF,6BAAGA,GAAVA,UAAWA,KAA6BA;wBAEvCG,MAAMA,CAACA,IAAIA,CAACA;oBACbA,CAACA;oBACFH,sBAACA;gBAADA,CAACA,AARDD,IAQCA;gBARYA,oBAAeA,kBAQ3BA,CAAAA;YACFA,CAACA,EAV2BD,IAAIA,GAAJA,YAAIA,KAAJA,YAAIA,QAU/BA;QAADA,CAACA,EAVqBD,KAAKA,GAALA,aAAKA,KAALA,aAAKA,QAU1BA;IAADA,CAACA,EAVaD,OAAOA,GAAPA,cAAOA,KAAPA,cAAOA,QAUpBA;AAADA,CAACA,EAVM,MAAM,KAAN,MAAM,QAUZ;AAED,IAAO,MAAM,CAoBZ;AApBD,WAAO,MAAM;IAACA,IAAAA,KAAKA,CAoBlBA;IApBaA,WAAAA,KAAKA;QAACQ,IAAAA,OAAOA,CAoB1BA;QApBmBA,WAAAA,OAAOA,EAACA,CAACA;YAC5BC;gBAKCC,oBAAoBA,SAAkCA;oBAAlCC,cAASA,GAATA,SAASA,CAAyBA;oBAD9CA,YAAOA,GAAOA,IAAIA,CAACA;oBAGvBA,AADAA,aAAaA;oBACbA,SAASA,CAACA,SAASA,CAACA,WAAWA,EAAEA,IAAIA,CAACA,CAACA;gBAC3CA,CAACA;gBANMD,wBAAGA,GAAVA,UAAWA,MAAyCA,IAAIE,EAAEA,CAACA,CAACA,IAAIA,CAACA,CAACA,CAACA;oBAAAA,MAAMA,CAACA,MAAMA,CAACA,IAAIA,CAACA,CAACA;gBAAAA,CAACA,CAAAA,CAACA;gBAQlFF,+BAAUA,GAAjBA;oBACCG,MAAMA,CAACA,OAAOA,CAACA;gBAChBA,CAACA;gBAEMH,4BAAOA,GAAdA;gBAEAI,CAACA;gBAEFJ,iBAACA;YAADA,CAACA,AAlBDD,IAkBCA;YAlBYA,kBAAUA,aAkBtBA,CAAAA;QACFA,CAACA,EApBmBD,OAAOA,GAAPA,aAAOA,KAAPA,aAAOA,QAoB1BA;IAADA,CAACA,EApBaR,KAAKA,GAALA,YAAKA,KAALA,YAAKA,QAoBlBA;AAADA,CAACA,EApBM,MAAM,KAAN,MAAM,QAoBZ;AAGD;IAAAe;IAAuFC,CAACA;IAA3CD,sCAAeA,GAAtBA,cAAmCE,MAAMA,CAACA,IAAIA,CAACA,CAAAA,CAACA;IAACF,mBAACA;AAADA,CAACA,AAAxF,IAAwF;AASxF,IAAO,MAAM,CAwBZ;AAxBD,WAAO,MAAM;IAACf,IAAAA,KAAKA,CAwBlBA;IAxBaA,WAAAA,KAAKA;QAACQ,IAAAA,SAASA,CAwB5BA;QAxBmBA,WAAAA,SAASA;YAACU,IAAAA,SAASA,CAwBtCA;YAxB6BA,WAAAA,SAASA,EAACA,CAACA;gBAExCC;oBACOC,eAAoBA,IAAWA;wBAAXC,SAAIA,GAAJA,IAAIA,CAAOA;oBAAIA,CAACA;oBACnCD,qBAAKA,GAAZA;wBACCE,MAAMA,CAACA,IAAIA,CAACA;oBACbA,CAACA;oBAEMF,sBAAMA,GAAbA,UAAcA,KAAYA;wBACzBG,MAAMA,CAACA,IAAIA,KAAKA,KAAKA,CAACA;oBACvBA,CAACA;oBAEMH,uBAAOA,GAAdA,cAA0BI,MAAMA,CAACA,IAAIA,CAACA,CAACA,CAACA;oBACzCJ,YAACA;gBAADA,CAACA,AAXDD,IAWCA;gBAXYA,eAAKA,QAWjBA,CAAAA;gBAEDA;oBAA0BM,wBAAYA;oBAAtCA;wBAA0BC,8BAAYA;oBAQtCA,CAACA;oBANAD,aAAaA;oBACNA,8BAAeA,GAAtBA;wBACCE,MAAMA,CAACA,IAAIA,KAAKA,CAACA,IAAIA,CAACA,CAACA;oBACxBA,CAACA;oBAGFF,WAACA;gBAADA,CAACA,AARDN,EAA0BA,YAAYA,EAQrCA;gBARYA,cAAIA,OAQhBA,CAAAA;YACFA,CAACA,EAxB6BD,SAASA,GAATA,mBAASA,KAATA,mBAASA,QAwBtCA;QAADA,CAACA,EAxBmBV,SAASA,GAATA,eAASA,KAATA,eAASA,QAwB5BA;IAADA,CAACA,EAxBaR,KAAKA,GAALA,YAAKA,KAALA,YAAKA,QAwBlBA;AAADA,CAACA,EAxBM,MAAM,KAAN,MAAM,QAwBZ"}
\ No newline at end of file
+{"version":3,"file":"recursiveClassReferenceTest.js","sourceRoot":"","sources":["recursiveClassReferenceTest.ts"],"names":["Sample","Sample.Actions","Sample.Actions.Thing","Sample.Actions.Thing.Find","Sample.Actions.Thing.Find.StartFindAction","Sample.Actions.Thing.Find.StartFindAction.constructor","Sample.Actions.Thing.Find.StartFindAction.getId","Sample.Actions.Thing.Find.StartFindAction.run","Sample.Thing","Sample.Thing.Widgets","Sample.Thing.Widgets.FindWidget","Sample.Thing.Widgets.FindWidget.constructor","Sample.Thing.Widgets.FindWidget.gar","Sample.Thing.Widgets.FindWidget.getDomNode","Sample.Thing.Widgets.FindWidget.destroy","AbstractMode","AbstractMode.constructor","AbstractMode.getInitialState","Sample.Thing.Languages","Sample.Thing.Languages.PlainText","Sample.Thing.Languages.PlainText.State","Sample.Thing.Languages.PlainText.State.constructor","Sample.Thing.Languages.PlainText.State.clone","Sample.Thing.Languages.PlainText.State.equals","Sample.Thing.Languages.PlainText.State.getMode","Sample.Thing.Languages.PlainText.Mode","Sample.Thing.Languages.PlainText.Mode.constructor","Sample.Thing.Languages.PlainText.Mode.getInitialState"],"mappings":"AAAA,iEAAiE;AACjE,0EAA0E;;;;;;AA8B1E,IAAO,MAAM,CAUZ;AAVD,WAAO,MAAM;IAACA,IAAAA,OAAOA,CAUpBA;IAVaA,WAAAA,OAAOA;QAACC,IAAAA,KAAKA,CAU1BA;QAVqBA,WAAAA,OAAKA;YAACC,IAAAA,IAAIA,CAU/BA;YAV2BA,WAAAA,IAAIA,EAACA,CAACA;gBACjCC;oBAAAC;oBAQAC,CAACA;oBANOD,+BAAKA,GAAZA,cAAiBE,MAAMA,CAACA,IAAIA,CAACA,CAACA,CAACA;oBAExBF,6BAAGA,GAAVA,UAAWA,KAA6BA;wBAEvCG,MAAMA,CAACA,IAAIA,CAACA;oBACbA,CAACA;oBACFH,sBAACA;gBAADA,CAACA,AARDD,IAQCA;gBARYA,oBAAeA,kBAQ3BA,CAAAA;YACFA,CAACA,EAV2BD,IAAIA,GAAJA,YAAIA,KAAJA,YAAIA,QAU/BA;QAADA,CAACA,EAVqBD,KAAKA,GAALA,aAAKA,KAALA,aAAKA,QAU1BA;IAADA,CAACA,EAVaD,OAAOA,GAAPA,cAAOA,KAAPA,cAAOA,QAUpBA;AAADA,CAACA,EAVM,MAAM,KAAN,MAAM,QAUZ;AAED,IAAO,MAAM,CAoBZ;AApBD,WAAO,MAAM;IAACA,IAAAA,KAAKA,CAoBlBA;IApBaA,WAAAA,KAAKA;QAACQ,IAAAA,OAAOA,CAoB1BA;QApBmBA,WAAAA,OAAOA,EAACA,CAACA;YAC5BC;gBAKCC,oBAAoBA,SAAkCA;oBAAlCC,cAASA,GAATA,SAASA,CAAyBA;oBAD9CA,YAAOA,GAAOA,IAAIA,CAACA;oBAGvBA,AADAA,aAAaA;oBACbA,SAASA,CAACA,SAASA,CAACA,WAAWA,EAAEA,IAAIA,CAACA,CAACA;gBAC3CA,CAACA;gBANMD,wBAAGA,GAAVA,UAAWA,MAAyCA,IAAIE,EAAEA,CAACA,CAACA,IAAIA,CAACA,CAACA,CAACA;oBAAAA,MAAMA,CAACA,MAAMA,CAACA,IAAIA,CAACA,CAACA;gBAAAA,CAACA,CAAAA,CAACA;gBAQlFF,+BAAUA,GAAjBA;oBACCG,MAAMA,CAACA,OAAOA,CAACA;gBAChBA,CAACA;gBAEMH,4BAAOA,GAAdA;gBAEAI,CAACA;gBAEFJ,iBAACA;YAADA,CAACA,AAlBDD,IAkBCA;YAlBYA,kBAAUA,aAkBtBA,CAAAA;QACFA,CAACA,EApBmBD,OAAOA,GAAPA,aAAOA,KAAPA,aAAOA,QAoB1BA;IAADA,CAACA,EApBaR,KAAKA,GAALA,YAAKA,KAALA,YAAKA,QAoBlBA;AAADA,CAACA,EApBM,MAAM,KAAN,MAAM,QAoBZ;AAGD;IAAAe;IAAuFC,CAACA;IAA3CD,sCAAeA,GAAtBA,cAAmCE,MAAMA,CAACA,IAAIA,CAACA,CAAAA,CAACA;IAACF,mBAACA;AAADA,CAACA,AAAxF,IAAwF;AASxF,IAAO,MAAM,CAwBZ;AAxBD,WAAO,MAAM;IAACf,IAAAA,KAAKA,CAwBlBA;IAxBaA,WAAAA,KAAKA;QAACQ,IAAAA,SAASA,CAwB5BA;QAxBmBA,WAAAA,SAASA;YAACU,IAAAA,SAASA,CAwBtCA;YAxB6BA,WAAAA,SAASA,EAACA,CAACA;gBAExCC;oBACOC,eAAoBA,IAAWA;wBAAXC,SAAIA,GAAJA,IAAIA,CAAOA;oBAAIA,CAACA;oBACnCD,qBAAKA,GAAZA;wBACCE,MAAMA,CAACA,IAAIA,CAACA;oBACbA,CAACA;oBAEMF,sBAAMA,GAAbA,UAAcA,KAAYA;wBACzBG,MAAMA,CAACA,IAAIA,KAAKA,KAAKA,CAACA;oBACvBA,CAACA;oBAEMH,uBAAOA,GAAdA,cAA0BI,MAAMA,CAACA,IAAIA,CAACA,CAACA,CAACA;oBACzCJ,YAACA;gBAADA,CAACA,AAXDD,IAWCA;gBAXYA,eAAKA,QAWjBA,CAAAA;gBAEDA;oBAA0BM,wBAAYA;oBAAtCA;wBAA0BC,8BAAYA;oBAQtCA,CAACA;oBANAD,aAAaA;oBACNA,8BAAeA,GAAtBA;wBACCE,MAAMA,CAACA,IAAIA,KAAKA,CAACA,IAAIA,CAACA,CAACA;oBACxBA,CAACA;oBAGFF,WAACA;gBAADA,CAACA,AARDN,EAA0BA,YAAYA,EAQrCA;gBARYA,cAAIA,OAQhBA,CAAAA;YACFA,CAACA,EAxB6BD,SAASA,GAATA,mBAASA,KAATA,mBAASA,QAwBtCA;QAADA,CAACA,EAxBmBV,SAASA,GAATA,eAASA,KAATA,eAASA,QAwB5BA;IAADA,CAACA,EAxBaR,KAAKA,GAALA,YAAKA,KAALA,YAAKA,QAwBlBA;AAADA,CAACA,EAxBM,MAAM,KAAN,MAAM,QAwBZ"}
\ No newline at end of file
diff --git a/tests/baselines/reference/recursiveClassReferenceTest.sourcemap.txt b/tests/baselines/reference/recursiveClassReferenceTest.sourcemap.txt
index 67031d420ea..8f45e0ea715 100644
--- a/tests/baselines/reference/recursiveClassReferenceTest.sourcemap.txt
+++ b/tests/baselines/reference/recursiveClassReferenceTest.sourcemap.txt
@@ -29,8 +29,7 @@ sourceFile:recursiveClassReferenceTest.ts
 >>>var __extends = (this && this.__extends) || function (d, b) {
 >>>    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
 >>>    function __() { this.constructor = d; }
->>>    __.prototype = b.prototype;
->>>    d.prototype = new __();
+>>>    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 >>>};
 >>>var Sample;
 1 >
@@ -82,10 +81,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >          		}
   >          	}
   >          }
-1 >Emitted(9, 1) Source(32, 1) + SourceIndex(0)
-2 >Emitted(9, 5) Source(32, 8) + SourceIndex(0)
-3 >Emitted(9, 11) Source(32, 14) + SourceIndex(0)
-4 >Emitted(9, 12) Source(42, 2) + SourceIndex(0)
+1 >Emitted(8, 1) Source(32, 1) + SourceIndex(0)
+2 >Emitted(8, 5) Source(32, 8) + SourceIndex(0)
+3 >Emitted(8, 11) Source(32, 14) + SourceIndex(0)
+4 >Emitted(8, 12) Source(42, 2) + SourceIndex(0)
 ---
 >>>(function (Sample) {
 1->
@@ -94,9 +93,9 @@ sourceFile:recursiveClassReferenceTest.ts
 1->
 2 >module 
 3 >           Sample
-1->Emitted(10, 1) Source(32, 1) + SourceIndex(0)
-2 >Emitted(10, 12) Source(32, 8) + SourceIndex(0)
-3 >Emitted(10, 18) Source(32, 14) + SourceIndex(0)
+1->Emitted(9, 1) Source(32, 1) + SourceIndex(0)
+2 >Emitted(9, 12) Source(32, 8) + SourceIndex(0)
+3 >Emitted(9, 18) Source(32, 14) + SourceIndex(0)
 ---
 >>>    var Actions;
 1 >^^^^
@@ -118,10 +117,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >               		}
   >               	}
   >               }
-1 >Emitted(11, 5) Source(32, 15) + SourceIndex(0) name (Sample)
-2 >Emitted(11, 9) Source(32, 15) + SourceIndex(0) name (Sample)
-3 >Emitted(11, 16) Source(32, 22) + SourceIndex(0) name (Sample)
-4 >Emitted(11, 17) Source(42, 2) + SourceIndex(0) name (Sample)
+1 >Emitted(10, 5) Source(32, 15) + SourceIndex(0) name (Sample)
+2 >Emitted(10, 9) Source(32, 15) + SourceIndex(0) name (Sample)
+3 >Emitted(10, 16) Source(32, 22) + SourceIndex(0) name (Sample)
+4 >Emitted(10, 17) Source(42, 2) + SourceIndex(0) name (Sample)
 ---
 >>>    (function (Actions) {
 1->^^^^
@@ -130,9 +129,9 @@ sourceFile:recursiveClassReferenceTest.ts
 1->
 2 >    
 3 >               Actions
-1->Emitted(12, 5) Source(32, 15) + SourceIndex(0) name (Sample)
-2 >Emitted(12, 16) Source(32, 15) + SourceIndex(0) name (Sample)
-3 >Emitted(12, 23) Source(32, 22) + SourceIndex(0) name (Sample)
+1->Emitted(11, 5) Source(32, 15) + SourceIndex(0) name (Sample)
+2 >Emitted(11, 16) Source(32, 15) + SourceIndex(0) name (Sample)
+3 >Emitted(11, 23) Source(32, 22) + SourceIndex(0) name (Sample)
 ---
 >>>        var Thing;
 1 >^^^^^^^^
@@ -154,10 +153,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >                 		}
   >                 	}
   >                 }
-1 >Emitted(13, 9) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
-2 >Emitted(13, 13) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
-3 >Emitted(13, 18) Source(32, 28) + SourceIndex(0) name (Sample.Actions)
-4 >Emitted(13, 19) Source(42, 2) + SourceIndex(0) name (Sample.Actions)
+1 >Emitted(12, 9) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
+2 >Emitted(12, 13) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
+3 >Emitted(12, 18) Source(32, 28) + SourceIndex(0) name (Sample.Actions)
+4 >Emitted(12, 19) Source(42, 2) + SourceIndex(0) name (Sample.Actions)
 ---
 >>>        (function (Thing_1) {
 1->^^^^^^^^
@@ -166,9 +165,9 @@ sourceFile:recursiveClassReferenceTest.ts
 1->
 2 >        
 3 >                   Thing
-1->Emitted(14, 9) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
-2 >Emitted(14, 20) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
-3 >Emitted(14, 27) Source(32, 28) + SourceIndex(0) name (Sample.Actions)
+1->Emitted(13, 9) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
+2 >Emitted(13, 20) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
+3 >Emitted(13, 27) Source(32, 28) + SourceIndex(0) name (Sample.Actions)
 ---
 >>>            var Find;
 1 >^^^^^^^^^^^^
@@ -190,10 +189,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >                    		}
   >                    	}
   >                    }
-1 >Emitted(15, 13) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
-2 >Emitted(15, 17) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
-3 >Emitted(15, 21) Source(32, 33) + SourceIndex(0) name (Sample.Actions.Thing)
-4 >Emitted(15, 22) Source(42, 2) + SourceIndex(0) name (Sample.Actions.Thing)
+1 >Emitted(14, 13) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
+2 >Emitted(14, 17) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
+3 >Emitted(14, 21) Source(32, 33) + SourceIndex(0) name (Sample.Actions.Thing)
+4 >Emitted(14, 22) Source(42, 2) + SourceIndex(0) name (Sample.Actions.Thing)
 ---
 >>>            (function (Find) {
 1->^^^^^^^^^^^^
@@ -207,24 +206,24 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                       Find
 4 >                            
 5 >                             {
-1->Emitted(16, 13) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
-2 >Emitted(16, 24) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
-3 >Emitted(16, 28) Source(32, 33) + SourceIndex(0) name (Sample.Actions.Thing)
-4 >Emitted(16, 30) Source(32, 34) + SourceIndex(0) name (Sample.Actions.Thing)
-5 >Emitted(16, 31) Source(32, 35) + SourceIndex(0) name (Sample.Actions.Thing)
+1->Emitted(15, 13) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
+2 >Emitted(15, 24) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
+3 >Emitted(15, 28) Source(32, 33) + SourceIndex(0) name (Sample.Actions.Thing)
+4 >Emitted(15, 30) Source(32, 34) + SourceIndex(0) name (Sample.Actions.Thing)
+5 >Emitted(15, 31) Source(32, 35) + SourceIndex(0) name (Sample.Actions.Thing)
 ---
 >>>                var StartFindAction = (function () {
 1->^^^^^^^^^^^^^^^^
 2 >                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1->
   >	
-1->Emitted(17, 17) Source(33, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find)
+1->Emitted(16, 17) Source(33, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find)
 ---
 >>>                    function StartFindAction() {
 1->^^^^^^^^^^^^^^^^^^^^
 2 >                    ^^->
 1->
-1->Emitted(18, 21) Source(33, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+1->Emitted(17, 21) Source(33, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
 ---
 >>>                    }
 1->^^^^^^^^^^^^^^^^^^^^
@@ -240,8 +239,8 @@ sourceFile:recursiveClassReferenceTest.ts
   >		}
   >	
 2 >                    }
-1->Emitted(19, 21) Source(41, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.constructor)
-2 >Emitted(19, 22) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.constructor)
+1->Emitted(18, 21) Source(41, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.constructor)
+2 >Emitted(18, 22) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.constructor)
 ---
 >>>                    StartFindAction.prototype.getId = function () { return "yo"; };
 1->^^^^^^^^^^^^^^^^^^^^
@@ -264,16 +263,16 @@ sourceFile:recursiveClassReferenceTest.ts
 8 >                                                                               ;
 9 >                                                                                 
 10>                                                                                 }
-1->Emitted(20, 21) Source(35, 10) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
-2 >Emitted(20, 52) Source(35, 15) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
-3 >Emitted(20, 55) Source(35, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
-4 >Emitted(20, 69) Source(35, 20) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
-5 >Emitted(20, 75) Source(35, 26) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
-6 >Emitted(20, 76) Source(35, 27) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
-7 >Emitted(20, 80) Source(35, 31) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
-8 >Emitted(20, 81) Source(35, 32) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
-9 >Emitted(20, 82) Source(35, 33) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
-10>Emitted(20, 83) Source(35, 34) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
+1->Emitted(19, 21) Source(35, 10) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+2 >Emitted(19, 52) Source(35, 15) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+3 >Emitted(19, 55) Source(35, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+4 >Emitted(19, 69) Source(35, 20) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
+5 >Emitted(19, 75) Source(35, 26) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
+6 >Emitted(19, 76) Source(35, 27) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
+7 >Emitted(19, 80) Source(35, 31) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
+8 >Emitted(19, 81) Source(35, 32) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
+9 >Emitted(19, 82) Source(35, 33) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
+10>Emitted(19, 83) Source(35, 34) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.getId)
 ---
 >>>                    StartFindAction.prototype.run = function (Thing) {
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -288,11 +287,11 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                                                 
 4 >                                                    public run(
 5 >                                                              Thing:Sample.Thing.ICodeThing
-1 >Emitted(21, 21) Source(37, 10) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
-2 >Emitted(21, 50) Source(37, 13) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
-3 >Emitted(21, 53) Source(37, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
-4 >Emitted(21, 63) Source(37, 14) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
-5 >Emitted(21, 68) Source(37, 43) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+1 >Emitted(20, 21) Source(37, 10) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+2 >Emitted(20, 50) Source(37, 13) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+3 >Emitted(20, 53) Source(37, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+4 >Emitted(20, 63) Source(37, 14) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+5 >Emitted(20, 68) Source(37, 43) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
 ---
 >>>                        return true;
 1 >^^^^^^^^^^^^^^^^^^^^^^^^
@@ -307,11 +306,11 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                               
 4 >                               true
 5 >                                   ;
-1 >Emitted(22, 25) Source(39, 4) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
-2 >Emitted(22, 31) Source(39, 10) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
-3 >Emitted(22, 32) Source(39, 11) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
-4 >Emitted(22, 36) Source(39, 15) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
-5 >Emitted(22, 37) Source(39, 16) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
+1 >Emitted(21, 25) Source(39, 4) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
+2 >Emitted(21, 31) Source(39, 10) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
+3 >Emitted(21, 32) Source(39, 11) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
+4 >Emitted(21, 36) Source(39, 15) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
+5 >Emitted(21, 37) Source(39, 16) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
 ---
 >>>                    };
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -320,8 +319,8 @@ sourceFile:recursiveClassReferenceTest.ts
 1 >
   >		
 2 >                    }
-1 >Emitted(23, 21) Source(40, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
-2 >Emitted(23, 22) Source(40, 4) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
+1 >Emitted(22, 21) Source(40, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
+2 >Emitted(22, 22) Source(40, 4) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction.run)
 ---
 >>>                    return StartFindAction;
 1->^^^^^^^^^^^^^^^^^^^^
@@ -329,8 +328,8 @@ sourceFile:recursiveClassReferenceTest.ts
 1->
   >	
 2 >                    }
-1->Emitted(24, 21) Source(41, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
-2 >Emitted(24, 43) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+1->Emitted(23, 21) Source(41, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+2 >Emitted(23, 43) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
 ---
 >>>                })();
 1 >^^^^^^^^^^^^^^^^
@@ -350,10 +349,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >                 			return true;
   >                 		}
   >                 	}
-1 >Emitted(25, 17) Source(41, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
-2 >Emitted(25, 18) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
-3 >Emitted(25, 18) Source(33, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find)
-4 >Emitted(25, 22) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find)
+1 >Emitted(24, 17) Source(41, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+2 >Emitted(24, 18) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find.StartFindAction)
+3 >Emitted(24, 18) Source(33, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find)
+4 >Emitted(24, 22) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find)
 ---
 >>>                Find.StartFindAction = StartFindAction;
 1->^^^^^^^^^^^^^^^^
@@ -373,10 +372,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >                                    		}
   >                                    	}
 4 >                                                      
-1->Emitted(26, 17) Source(33, 15) + SourceIndex(0) name (Sample.Actions.Thing.Find)
-2 >Emitted(26, 37) Source(33, 30) + SourceIndex(0) name (Sample.Actions.Thing.Find)
-3 >Emitted(26, 55) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find)
-4 >Emitted(26, 56) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find)
+1->Emitted(25, 17) Source(33, 15) + SourceIndex(0) name (Sample.Actions.Thing.Find)
+2 >Emitted(25, 37) Source(33, 30) + SourceIndex(0) name (Sample.Actions.Thing.Find)
+3 >Emitted(25, 55) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find)
+4 >Emitted(25, 56) Source(41, 3) + SourceIndex(0) name (Sample.Actions.Thing.Find)
 ---
 >>>            })(Find = Thing_1.Find || (Thing_1.Find = {}));
 1->^^^^^^^^^^^^
@@ -408,15 +407,15 @@ sourceFile:recursiveClassReferenceTest.ts
   >                                                   		}
   >                                                   	}
   >                                                   }
-1->Emitted(27, 13) Source(42, 1) + SourceIndex(0) name (Sample.Actions.Thing.Find)
-2 >Emitted(27, 14) Source(42, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find)
-3 >Emitted(27, 16) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
-4 >Emitted(27, 20) Source(32, 33) + SourceIndex(0) name (Sample.Actions.Thing)
-5 >Emitted(27, 23) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
-6 >Emitted(27, 35) Source(32, 33) + SourceIndex(0) name (Sample.Actions.Thing)
-7 >Emitted(27, 40) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
-8 >Emitted(27, 52) Source(32, 33) + SourceIndex(0) name (Sample.Actions.Thing)
-9 >Emitted(27, 60) Source(42, 2) + SourceIndex(0) name (Sample.Actions.Thing)
+1->Emitted(26, 13) Source(42, 1) + SourceIndex(0) name (Sample.Actions.Thing.Find)
+2 >Emitted(26, 14) Source(42, 2) + SourceIndex(0) name (Sample.Actions.Thing.Find)
+3 >Emitted(26, 16) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
+4 >Emitted(26, 20) Source(32, 33) + SourceIndex(0) name (Sample.Actions.Thing)
+5 >Emitted(26, 23) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
+6 >Emitted(26, 35) Source(32, 33) + SourceIndex(0) name (Sample.Actions.Thing)
+7 >Emitted(26, 40) Source(32, 29) + SourceIndex(0) name (Sample.Actions.Thing)
+8 >Emitted(26, 52) Source(32, 33) + SourceIndex(0) name (Sample.Actions.Thing)
+9 >Emitted(26, 60) Source(42, 2) + SourceIndex(0) name (Sample.Actions.Thing)
 ---
 >>>        })(Thing = Actions.Thing || (Actions.Thing = {}));
 1 >^^^^^^^^
@@ -448,15 +447,15 @@ sourceFile:recursiveClassReferenceTest.ts
   >                                                  		}
   >                                                  	}
   >                                                  }
-1 >Emitted(28, 9) Source(42, 1) + SourceIndex(0) name (Sample.Actions.Thing)
-2 >Emitted(28, 10) Source(42, 2) + SourceIndex(0) name (Sample.Actions.Thing)
-3 >Emitted(28, 12) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
-4 >Emitted(28, 17) Source(32, 28) + SourceIndex(0) name (Sample.Actions)
-5 >Emitted(28, 20) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
-6 >Emitted(28, 33) Source(32, 28) + SourceIndex(0) name (Sample.Actions)
-7 >Emitted(28, 38) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
-8 >Emitted(28, 51) Source(32, 28) + SourceIndex(0) name (Sample.Actions)
-9 >Emitted(28, 59) Source(42, 2) + SourceIndex(0) name (Sample.Actions)
+1 >Emitted(27, 9) Source(42, 1) + SourceIndex(0) name (Sample.Actions.Thing)
+2 >Emitted(27, 10) Source(42, 2) + SourceIndex(0) name (Sample.Actions.Thing)
+3 >Emitted(27, 12) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
+4 >Emitted(27, 17) Source(32, 28) + SourceIndex(0) name (Sample.Actions)
+5 >Emitted(27, 20) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
+6 >Emitted(27, 33) Source(32, 28) + SourceIndex(0) name (Sample.Actions)
+7 >Emitted(27, 38) Source(32, 23) + SourceIndex(0) name (Sample.Actions)
+8 >Emitted(27, 51) Source(32, 28) + SourceIndex(0) name (Sample.Actions)
+9 >Emitted(27, 59) Source(42, 2) + SourceIndex(0) name (Sample.Actions)
 ---
 >>>    })(Actions = Sample.Actions || (Sample.Actions = {}));
 1->^^^^
@@ -487,15 +486,15 @@ sourceFile:recursiveClassReferenceTest.ts
   >                                                  		}
   >                                                  	}
   >                                                  }
-1->Emitted(29, 5) Source(42, 1) + SourceIndex(0) name (Sample.Actions)
-2 >Emitted(29, 6) Source(42, 2) + SourceIndex(0) name (Sample.Actions)
-3 >Emitted(29, 8) Source(32, 15) + SourceIndex(0) name (Sample)
-4 >Emitted(29, 15) Source(32, 22) + SourceIndex(0) name (Sample)
-5 >Emitted(29, 18) Source(32, 15) + SourceIndex(0) name (Sample)
-6 >Emitted(29, 32) Source(32, 22) + SourceIndex(0) name (Sample)
-7 >Emitted(29, 37) Source(32, 15) + SourceIndex(0) name (Sample)
-8 >Emitted(29, 51) Source(32, 22) + SourceIndex(0) name (Sample)
-9 >Emitted(29, 59) Source(42, 2) + SourceIndex(0) name (Sample)
+1->Emitted(28, 5) Source(42, 1) + SourceIndex(0) name (Sample.Actions)
+2 >Emitted(28, 6) Source(42, 2) + SourceIndex(0) name (Sample.Actions)
+3 >Emitted(28, 8) Source(32, 15) + SourceIndex(0) name (Sample)
+4 >Emitted(28, 15) Source(32, 22) + SourceIndex(0) name (Sample)
+5 >Emitted(28, 18) Source(32, 15) + SourceIndex(0) name (Sample)
+6 >Emitted(28, 32) Source(32, 22) + SourceIndex(0) name (Sample)
+7 >Emitted(28, 37) Source(32, 15) + SourceIndex(0) name (Sample)
+8 >Emitted(28, 51) Source(32, 22) + SourceIndex(0) name (Sample)
+9 >Emitted(28, 59) Source(42, 2) + SourceIndex(0) name (Sample)
 ---
 >>>})(Sample || (Sample = {}));
 1 >
@@ -522,13 +521,13 @@ sourceFile:recursiveClassReferenceTest.ts
   >                    		}
   >                    	}
   >                    }
-1 >Emitted(30, 1) Source(42, 1) + SourceIndex(0) name (Sample)
-2 >Emitted(30, 2) Source(42, 2) + SourceIndex(0) name (Sample)
-3 >Emitted(30, 4) Source(32, 8) + SourceIndex(0)
-4 >Emitted(30, 10) Source(32, 14) + SourceIndex(0)
-5 >Emitted(30, 15) Source(32, 8) + SourceIndex(0)
-6 >Emitted(30, 21) Source(32, 14) + SourceIndex(0)
-7 >Emitted(30, 29) Source(42, 2) + SourceIndex(0)
+1 >Emitted(29, 1) Source(42, 1) + SourceIndex(0) name (Sample)
+2 >Emitted(29, 2) Source(42, 2) + SourceIndex(0) name (Sample)
+3 >Emitted(29, 4) Source(32, 8) + SourceIndex(0)
+4 >Emitted(29, 10) Source(32, 14) + SourceIndex(0)
+5 >Emitted(29, 15) Source(32, 8) + SourceIndex(0)
+6 >Emitted(29, 21) Source(32, 14) + SourceIndex(0)
+7 >Emitted(29, 29) Source(42, 2) + SourceIndex(0)
 ---
 >>>var Sample;
 1 >
@@ -562,10 +561,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >          
   >          	}
   >          }
-1 >Emitted(31, 1) Source(44, 1) + SourceIndex(0)
-2 >Emitted(31, 5) Source(44, 8) + SourceIndex(0)
-3 >Emitted(31, 11) Source(44, 14) + SourceIndex(0)
-4 >Emitted(31, 12) Source(64, 2) + SourceIndex(0)
+1 >Emitted(30, 1) Source(44, 1) + SourceIndex(0)
+2 >Emitted(30, 5) Source(44, 8) + SourceIndex(0)
+3 >Emitted(30, 11) Source(44, 14) + SourceIndex(0)
+4 >Emitted(30, 12) Source(64, 2) + SourceIndex(0)
 ---
 >>>(function (Sample) {
 1->
@@ -574,9 +573,9 @@ sourceFile:recursiveClassReferenceTest.ts
 1->
 2 >module 
 3 >           Sample
-1->Emitted(32, 1) Source(44, 1) + SourceIndex(0)
-2 >Emitted(32, 12) Source(44, 8) + SourceIndex(0)
-3 >Emitted(32, 18) Source(44, 14) + SourceIndex(0)
+1->Emitted(31, 1) Source(44, 1) + SourceIndex(0)
+2 >Emitted(31, 12) Source(44, 8) + SourceIndex(0)
+3 >Emitted(31, 18) Source(44, 14) + SourceIndex(0)
 ---
 >>>    var Thing;
 1 >^^^^
@@ -608,10 +607,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >             
   >             	}
   >             }
-1 >Emitted(33, 5) Source(44, 15) + SourceIndex(0) name (Sample)
-2 >Emitted(33, 9) Source(44, 15) + SourceIndex(0) name (Sample)
-3 >Emitted(33, 14) Source(44, 20) + SourceIndex(0) name (Sample)
-4 >Emitted(33, 15) Source(64, 2) + SourceIndex(0) name (Sample)
+1 >Emitted(32, 5) Source(44, 15) + SourceIndex(0) name (Sample)
+2 >Emitted(32, 9) Source(44, 15) + SourceIndex(0) name (Sample)
+3 >Emitted(32, 14) Source(44, 20) + SourceIndex(0) name (Sample)
+4 >Emitted(32, 15) Source(64, 2) + SourceIndex(0) name (Sample)
 ---
 >>>    (function (Thing) {
 1->^^^^
@@ -621,9 +620,9 @@ sourceFile:recursiveClassReferenceTest.ts
 1->
 2 >    
 3 >               Thing
-1->Emitted(34, 5) Source(44, 15) + SourceIndex(0) name (Sample)
-2 >Emitted(34, 16) Source(44, 15) + SourceIndex(0) name (Sample)
-3 >Emitted(34, 21) Source(44, 20) + SourceIndex(0) name (Sample)
+1->Emitted(33, 5) Source(44, 15) + SourceIndex(0) name (Sample)
+2 >Emitted(33, 16) Source(44, 15) + SourceIndex(0) name (Sample)
+3 >Emitted(33, 21) Source(44, 20) + SourceIndex(0) name (Sample)
 ---
 >>>        var Widgets;
 1->^^^^^^^^
@@ -655,10 +654,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >                   
   >                   	}
   >                   }
-1->Emitted(35, 9) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
-2 >Emitted(35, 13) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
-3 >Emitted(35, 20) Source(44, 28) + SourceIndex(0) name (Sample.Thing)
-4 >Emitted(35, 21) Source(64, 2) + SourceIndex(0) name (Sample.Thing)
+1->Emitted(34, 9) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
+2 >Emitted(34, 13) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
+3 >Emitted(34, 20) Source(44, 28) + SourceIndex(0) name (Sample.Thing)
+4 >Emitted(34, 21) Source(64, 2) + SourceIndex(0) name (Sample.Thing)
 ---
 >>>        (function (Widgets) {
 1->^^^^^^^^
@@ -672,18 +671,18 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                   Widgets
 4 >                           
 5 >                            {
-1->Emitted(36, 9) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
-2 >Emitted(36, 20) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
-3 >Emitted(36, 27) Source(44, 28) + SourceIndex(0) name (Sample.Thing)
-4 >Emitted(36, 29) Source(44, 29) + SourceIndex(0) name (Sample.Thing)
-5 >Emitted(36, 30) Source(44, 30) + SourceIndex(0) name (Sample.Thing)
+1->Emitted(35, 9) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
+2 >Emitted(35, 20) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
+3 >Emitted(35, 27) Source(44, 28) + SourceIndex(0) name (Sample.Thing)
+4 >Emitted(35, 29) Source(44, 29) + SourceIndex(0) name (Sample.Thing)
+5 >Emitted(35, 30) Source(44, 30) + SourceIndex(0) name (Sample.Thing)
 ---
 >>>            var FindWidget = (function () {
 1->^^^^^^^^^^^^
 2 >            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1->
   >	
-1->Emitted(37, 13) Source(45, 2) + SourceIndex(0) name (Sample.Thing.Widgets)
+1->Emitted(36, 13) Source(45, 2) + SourceIndex(0) name (Sample.Thing.Widgets)
 ---
 >>>                function FindWidget(codeThing) {
 1->^^^^^^^^^^^^^^^^
@@ -698,9 +697,9 @@ sourceFile:recursiveClassReferenceTest.ts
   >		
 2 >                constructor(private 
 3 >                                    codeThing: Sample.Thing.ICodeThing
-1->Emitted(38, 17) Source(50, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-2 >Emitted(38, 37) Source(50, 23) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-3 >Emitted(38, 46) Source(50, 57) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+1->Emitted(37, 17) Source(50, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+2 >Emitted(37, 37) Source(50, 23) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+3 >Emitted(37, 46) Source(50, 57) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
 ---
 >>>                    this.codeThing = codeThing;
 1->^^^^^^^^^^^^^^^^^^^^
@@ -713,11 +712,11 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                                  
 4 >                                     codeThing
 5 >                                              : Sample.Thing.ICodeThing
-1->Emitted(39, 21) Source(50, 23) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-2 >Emitted(39, 35) Source(50, 32) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-3 >Emitted(39, 38) Source(50, 23) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-4 >Emitted(39, 47) Source(50, 32) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-5 >Emitted(39, 48) Source(50, 57) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+1->Emitted(38, 21) Source(50, 23) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+2 >Emitted(38, 35) Source(50, 32) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+3 >Emitted(38, 38) Source(50, 23) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+4 >Emitted(38, 47) Source(50, 32) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+5 >Emitted(38, 48) Source(50, 57) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
 ---
 >>>                    this.domNode = null;
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -730,11 +729,11 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                                :any = 
 4 >                                   null
 5 >                                       ;
-1 >Emitted(40, 21) Source(49, 11) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-2 >Emitted(40, 33) Source(49, 18) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-3 >Emitted(40, 36) Source(49, 25) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-4 >Emitted(40, 40) Source(49, 29) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-5 >Emitted(40, 41) Source(49, 30) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+1 >Emitted(39, 21) Source(49, 11) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+2 >Emitted(39, 33) Source(49, 18) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+3 >Emitted(39, 36) Source(49, 25) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+4 >Emitted(39, 40) Source(49, 29) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+5 >Emitted(39, 41) Source(49, 30) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
 ---
 >>>                    // scenario 1
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -747,9 +746,9 @@ sourceFile:recursiveClassReferenceTest.ts
   >		    
 2 >                    
 3 >                    // scenario 1
-1 >Emitted(41, 21) Source(52, 7) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-2 >Emitted(41, 21) Source(51, 7) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-3 >Emitted(41, 34) Source(51, 20) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+1 >Emitted(40, 21) Source(52, 7) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+2 >Emitted(40, 21) Source(51, 7) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+3 >Emitted(40, 34) Source(51, 20) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
 ---
 >>>                    codeThing.addWidget("addWidget", this);
 1->^^^^^^^^^^^^^^^^^^^^
@@ -773,16 +772,16 @@ sourceFile:recursiveClassReferenceTest.ts
 8 >                                                     this
 9 >                                                         )
 10>                                                          ;
-1->Emitted(42, 21) Source(52, 7) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-2 >Emitted(42, 30) Source(52, 16) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-3 >Emitted(42, 31) Source(52, 17) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-4 >Emitted(42, 40) Source(52, 26) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-5 >Emitted(42, 41) Source(52, 27) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-6 >Emitted(42, 52) Source(52, 38) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-7 >Emitted(42, 54) Source(52, 40) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-8 >Emitted(42, 58) Source(52, 44) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-9 >Emitted(42, 59) Source(52, 45) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-10>Emitted(42, 60) Source(52, 46) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+1->Emitted(41, 21) Source(52, 7) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+2 >Emitted(41, 30) Source(52, 16) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+3 >Emitted(41, 31) Source(52, 17) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+4 >Emitted(41, 40) Source(52, 26) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+5 >Emitted(41, 41) Source(52, 27) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+6 >Emitted(41, 52) Source(52, 38) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+7 >Emitted(41, 54) Source(52, 40) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+8 >Emitted(41, 58) Source(52, 44) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+9 >Emitted(41, 59) Source(52, 45) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+10>Emitted(41, 60) Source(52, 46) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
 ---
 >>>                }
 1 >^^^^^^^^^^^^^^^^
@@ -791,8 +790,8 @@ sourceFile:recursiveClassReferenceTest.ts
 1 >
   >		
 2 >                }
-1 >Emitted(43, 17) Source(53, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
-2 >Emitted(43, 18) Source(53, 4) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+1 >Emitted(42, 17) Source(53, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
+2 >Emitted(42, 18) Source(53, 4) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.constructor)
 ---
 >>>                FindWidget.prototype.gar = function (runner) { if (true) {
 1->^^^^^^^^^^^^^^^^
@@ -821,19 +820,19 @@ sourceFile:recursiveClassReferenceTest.ts
 11>                                                                       )
 12>                                                                         
 13>                                                                         {
-1->Emitted(44, 17) Source(47, 10) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-2 >Emitted(44, 41) Source(47, 13) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-3 >Emitted(44, 44) Source(47, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-4 >Emitted(44, 54) Source(47, 14) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-5 >Emitted(44, 60) Source(47, 55) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-6 >Emitted(44, 64) Source(47, 59) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-7 >Emitted(44, 66) Source(47, 61) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-8 >Emitted(44, 67) Source(47, 62) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-9 >Emitted(44, 68) Source(47, 63) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-10>Emitted(44, 72) Source(47, 67) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-11>Emitted(44, 73) Source(47, 68) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-12>Emitted(44, 74) Source(47, 69) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-13>Emitted(44, 75) Source(47, 70) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+1->Emitted(43, 17) Source(47, 10) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+2 >Emitted(43, 41) Source(47, 13) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+3 >Emitted(43, 44) Source(47, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+4 >Emitted(43, 54) Source(47, 14) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+5 >Emitted(43, 60) Source(47, 55) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+6 >Emitted(43, 64) Source(47, 59) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+7 >Emitted(43, 66) Source(47, 61) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+8 >Emitted(43, 67) Source(47, 62) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+9 >Emitted(43, 68) Source(47, 63) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+10>Emitted(43, 72) Source(47, 67) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+11>Emitted(43, 73) Source(47, 68) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+12>Emitted(43, 74) Source(47, 69) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+13>Emitted(43, 75) Source(47, 70) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
 ---
 >>>                    return runner(this);
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -852,14 +851,14 @@ sourceFile:recursiveClassReferenceTest.ts
 6 >                                  this
 7 >                                      )
 8 >                                       ;
-1 >Emitted(45, 21) Source(47, 70) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-2 >Emitted(45, 27) Source(47, 76) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-3 >Emitted(45, 28) Source(47, 77) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-4 >Emitted(45, 34) Source(47, 83) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-5 >Emitted(45, 35) Source(47, 84) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-6 >Emitted(45, 39) Source(47, 88) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-7 >Emitted(45, 40) Source(47, 89) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-8 >Emitted(45, 41) Source(47, 90) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+1 >Emitted(44, 21) Source(47, 70) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+2 >Emitted(44, 27) Source(47, 76) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+3 >Emitted(44, 28) Source(47, 77) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+4 >Emitted(44, 34) Source(47, 83) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+5 >Emitted(44, 35) Source(47, 84) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+6 >Emitted(44, 39) Source(47, 88) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+7 >Emitted(44, 40) Source(47, 89) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+8 >Emitted(44, 41) Source(47, 90) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
 ---
 >>>                } };
 1 >^^^^^^^^^^^^^^^^
@@ -871,10 +870,10 @@ sourceFile:recursiveClassReferenceTest.ts
 2 >                }
 3 >                 
 4 >                  }
-1 >Emitted(46, 17) Source(47, 90) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-2 >Emitted(46, 18) Source(47, 91) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-3 >Emitted(46, 19) Source(47, 91) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
-4 >Emitted(46, 20) Source(47, 92) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+1 >Emitted(45, 17) Source(47, 90) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+2 >Emitted(45, 18) Source(47, 91) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+3 >Emitted(45, 19) Source(47, 91) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
+4 >Emitted(45, 20) Source(47, 92) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.gar)
 ---
 >>>                FindWidget.prototype.getDomNode = function () {
 1->^^^^^^^^^^^^^^^^
@@ -891,9 +890,9 @@ sourceFile:recursiveClassReferenceTest.ts
   >		public 
 2 >                getDomNode
 3 >                                               
-1->Emitted(47, 17) Source(55, 10) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-2 >Emitted(47, 48) Source(55, 20) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-3 >Emitted(47, 51) Source(55, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+1->Emitted(46, 17) Source(55, 10) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+2 >Emitted(46, 48) Source(55, 20) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+3 >Emitted(46, 51) Source(55, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
 ---
 >>>                    return domNode;
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -907,11 +906,11 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                           
 4 >                           domNode
 5 >                                  ;
-1 >Emitted(48, 21) Source(56, 4) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
-2 >Emitted(48, 27) Source(56, 10) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
-3 >Emitted(48, 28) Source(56, 11) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
-4 >Emitted(48, 35) Source(56, 18) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
-5 >Emitted(48, 36) Source(56, 19) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
+1 >Emitted(47, 21) Source(56, 4) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
+2 >Emitted(47, 27) Source(56, 10) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
+3 >Emitted(47, 28) Source(56, 11) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
+4 >Emitted(47, 35) Source(56, 18) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
+5 >Emitted(47, 36) Source(56, 19) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
 ---
 >>>                };
 1 >^^^^^^^^^^^^^^^^
@@ -920,8 +919,8 @@ sourceFile:recursiveClassReferenceTest.ts
 1 >
   >		
 2 >                }
-1 >Emitted(49, 17) Source(57, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
-2 >Emitted(49, 18) Source(57, 4) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
+1 >Emitted(48, 17) Source(57, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
+2 >Emitted(48, 18) Source(57, 4) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.getDomNode)
 ---
 >>>                FindWidget.prototype.destroy = function () {
 1->^^^^^^^^^^^^^^^^
@@ -932,9 +931,9 @@ sourceFile:recursiveClassReferenceTest.ts
   >		public 
 2 >                destroy
 3 >                                            
-1->Emitted(50, 17) Source(59, 10) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-2 >Emitted(50, 45) Source(59, 17) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-3 >Emitted(50, 48) Source(59, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+1->Emitted(49, 17) Source(59, 10) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+2 >Emitted(49, 45) Source(59, 17) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+3 >Emitted(49, 48) Source(59, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
 ---
 >>>                };
 1 >^^^^^^^^^^^^^^^^
@@ -944,8 +943,8 @@ sourceFile:recursiveClassReferenceTest.ts
   >
   >		
 2 >                }
-1 >Emitted(51, 17) Source(61, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.destroy)
-2 >Emitted(51, 18) Source(61, 4) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.destroy)
+1 >Emitted(50, 17) Source(61, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.destroy)
+2 >Emitted(50, 18) Source(61, 4) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget.destroy)
 ---
 >>>                return FindWidget;
 1->^^^^^^^^^^^^^^^^
@@ -954,8 +953,8 @@ sourceFile:recursiveClassReferenceTest.ts
   >
   >	
 2 >                }
-1->Emitted(52, 17) Source(63, 2) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-2 >Emitted(52, 34) Source(63, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+1->Emitted(51, 17) Source(63, 2) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+2 >Emitted(51, 34) Source(63, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
 ---
 >>>            })();
 1 >^^^^^^^^^^^^
@@ -985,10 +984,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >             		}
   >             
   >             	}
-1 >Emitted(53, 13) Source(63, 2) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-2 >Emitted(53, 14) Source(63, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
-3 >Emitted(53, 14) Source(45, 2) + SourceIndex(0) name (Sample.Thing.Widgets)
-4 >Emitted(53, 18) Source(63, 3) + SourceIndex(0) name (Sample.Thing.Widgets)
+1 >Emitted(52, 13) Source(63, 2) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+2 >Emitted(52, 14) Source(63, 3) + SourceIndex(0) name (Sample.Thing.Widgets.FindWidget)
+3 >Emitted(52, 14) Source(45, 2) + SourceIndex(0) name (Sample.Thing.Widgets)
+4 >Emitted(52, 18) Source(63, 3) + SourceIndex(0) name (Sample.Thing.Widgets)
 ---
 >>>            Widgets.FindWidget = FindWidget;
 1->^^^^^^^^^^^^
@@ -1018,10 +1017,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >                              
   >                              	}
 4 >                                           
-1->Emitted(54, 13) Source(45, 15) + SourceIndex(0) name (Sample.Thing.Widgets)
-2 >Emitted(54, 31) Source(45, 25) + SourceIndex(0) name (Sample.Thing.Widgets)
-3 >Emitted(54, 44) Source(63, 3) + SourceIndex(0) name (Sample.Thing.Widgets)
-4 >Emitted(54, 45) Source(63, 3) + SourceIndex(0) name (Sample.Thing.Widgets)
+1->Emitted(53, 13) Source(45, 15) + SourceIndex(0) name (Sample.Thing.Widgets)
+2 >Emitted(53, 31) Source(45, 25) + SourceIndex(0) name (Sample.Thing.Widgets)
+3 >Emitted(53, 44) Source(63, 3) + SourceIndex(0) name (Sample.Thing.Widgets)
+4 >Emitted(53, 45) Source(63, 3) + SourceIndex(0) name (Sample.Thing.Widgets)
 ---
 >>>        })(Widgets = Thing.Widgets || (Thing.Widgets = {}));
 1->^^^^^^^^
@@ -1063,15 +1062,15 @@ sourceFile:recursiveClassReferenceTest.ts
   >                                                    
   >                                                    	}
   >                                                    }
-1->Emitted(55, 9) Source(64, 1) + SourceIndex(0) name (Sample.Thing.Widgets)
-2 >Emitted(55, 10) Source(64, 2) + SourceIndex(0) name (Sample.Thing.Widgets)
-3 >Emitted(55, 12) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
-4 >Emitted(55, 19) Source(44, 28) + SourceIndex(0) name (Sample.Thing)
-5 >Emitted(55, 22) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
-6 >Emitted(55, 35) Source(44, 28) + SourceIndex(0) name (Sample.Thing)
-7 >Emitted(55, 40) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
-8 >Emitted(55, 53) Source(44, 28) + SourceIndex(0) name (Sample.Thing)
-9 >Emitted(55, 61) Source(64, 2) + SourceIndex(0) name (Sample.Thing)
+1->Emitted(54, 9) Source(64, 1) + SourceIndex(0) name (Sample.Thing.Widgets)
+2 >Emitted(54, 10) Source(64, 2) + SourceIndex(0) name (Sample.Thing.Widgets)
+3 >Emitted(54, 12) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
+4 >Emitted(54, 19) Source(44, 28) + SourceIndex(0) name (Sample.Thing)
+5 >Emitted(54, 22) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
+6 >Emitted(54, 35) Source(44, 28) + SourceIndex(0) name (Sample.Thing)
+7 >Emitted(54, 40) Source(44, 21) + SourceIndex(0) name (Sample.Thing)
+8 >Emitted(54, 53) Source(44, 28) + SourceIndex(0) name (Sample.Thing)
+9 >Emitted(54, 61) Source(64, 2) + SourceIndex(0) name (Sample.Thing)
 ---
 >>>    })(Thing = Sample.Thing || (Sample.Thing = {}));
 1 >^^^^
@@ -1112,15 +1111,15 @@ sourceFile:recursiveClassReferenceTest.ts
   >                                            
   >                                            	}
   >                                            }
-1 >Emitted(56, 5) Source(64, 1) + SourceIndex(0) name (Sample.Thing)
-2 >Emitted(56, 6) Source(64, 2) + SourceIndex(0) name (Sample.Thing)
-3 >Emitted(56, 8) Source(44, 15) + SourceIndex(0) name (Sample)
-4 >Emitted(56, 13) Source(44, 20) + SourceIndex(0) name (Sample)
-5 >Emitted(56, 16) Source(44, 15) + SourceIndex(0) name (Sample)
-6 >Emitted(56, 28) Source(44, 20) + SourceIndex(0) name (Sample)
-7 >Emitted(56, 33) Source(44, 15) + SourceIndex(0) name (Sample)
-8 >Emitted(56, 45) Source(44, 20) + SourceIndex(0) name (Sample)
-9 >Emitted(56, 53) Source(64, 2) + SourceIndex(0) name (Sample)
+1 >Emitted(55, 5) Source(64, 1) + SourceIndex(0) name (Sample.Thing)
+2 >Emitted(55, 6) Source(64, 2) + SourceIndex(0) name (Sample.Thing)
+3 >Emitted(55, 8) Source(44, 15) + SourceIndex(0) name (Sample)
+4 >Emitted(55, 13) Source(44, 20) + SourceIndex(0) name (Sample)
+5 >Emitted(55, 16) Source(44, 15) + SourceIndex(0) name (Sample)
+6 >Emitted(55, 28) Source(44, 20) + SourceIndex(0) name (Sample)
+7 >Emitted(55, 33) Source(44, 15) + SourceIndex(0) name (Sample)
+8 >Emitted(55, 45) Source(44, 20) + SourceIndex(0) name (Sample)
+9 >Emitted(55, 53) Source(64, 2) + SourceIndex(0) name (Sample)
 ---
 >>>})(Sample || (Sample = {}));
 1 >
@@ -1158,13 +1157,13 @@ sourceFile:recursiveClassReferenceTest.ts
   >                    
   >                    	}
   >                    }
-1 >Emitted(57, 1) Source(64, 1) + SourceIndex(0) name (Sample)
-2 >Emitted(57, 2) Source(64, 2) + SourceIndex(0) name (Sample)
-3 >Emitted(57, 4) Source(44, 8) + SourceIndex(0)
-4 >Emitted(57, 10) Source(44, 14) + SourceIndex(0)
-5 >Emitted(57, 15) Source(44, 8) + SourceIndex(0)
-6 >Emitted(57, 21) Source(44, 14) + SourceIndex(0)
-7 >Emitted(57, 29) Source(64, 2) + SourceIndex(0)
+1 >Emitted(56, 1) Source(64, 1) + SourceIndex(0) name (Sample)
+2 >Emitted(56, 2) Source(64, 2) + SourceIndex(0) name (Sample)
+3 >Emitted(56, 4) Source(44, 8) + SourceIndex(0)
+4 >Emitted(56, 10) Source(44, 14) + SourceIndex(0)
+5 >Emitted(56, 15) Source(44, 8) + SourceIndex(0)
+6 >Emitted(56, 21) Source(44, 14) + SourceIndex(0)
+7 >Emitted(56, 29) Source(64, 2) + SourceIndex(0)
 ---
 >>>var AbstractMode = (function () {
 1->
@@ -1173,13 +1172,13 @@ sourceFile:recursiveClassReferenceTest.ts
   >
   >interface IMode { getInitialState(): IState;} 
   >
-1->Emitted(58, 1) Source(67, 1) + SourceIndex(0)
+1->Emitted(57, 1) Source(67, 1) + SourceIndex(0)
 ---
 >>>    function AbstractMode() {
 1->^^^^
 2 >    ^^->
 1->
-1->Emitted(59, 5) Source(67, 1) + SourceIndex(0) name (AbstractMode)
+1->Emitted(58, 5) Source(67, 1) + SourceIndex(0) name (AbstractMode)
 ---
 >>>    }
 1->^^^^
@@ -1187,8 +1186,8 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1->class AbstractMode implements IMode { public getInitialState(): IState { return null;} 
 2 >    }
-1->Emitted(60, 5) Source(67, 88) + SourceIndex(0) name (AbstractMode.constructor)
-2 >Emitted(60, 6) Source(67, 89) + SourceIndex(0) name (AbstractMode.constructor)
+1->Emitted(59, 5) Source(67, 88) + SourceIndex(0) name (AbstractMode.constructor)
+2 >Emitted(59, 6) Source(67, 89) + SourceIndex(0) name (AbstractMode.constructor)
 ---
 >>>    AbstractMode.prototype.getInitialState = function () { return null; };
 1->^^^^
@@ -1211,24 +1210,24 @@ sourceFile:recursiveClassReferenceTest.ts
 8 >                                                                      ;
 9 >                                                                       
 10>                                                                        }
-1->Emitted(61, 5) Source(67, 46) + SourceIndex(0) name (AbstractMode)
-2 >Emitted(61, 43) Source(67, 61) + SourceIndex(0) name (AbstractMode)
-3 >Emitted(61, 46) Source(67, 39) + SourceIndex(0) name (AbstractMode)
-4 >Emitted(61, 60) Source(67, 74) + SourceIndex(0) name (AbstractMode.getInitialState)
-5 >Emitted(61, 66) Source(67, 80) + SourceIndex(0) name (AbstractMode.getInitialState)
-6 >Emitted(61, 67) Source(67, 81) + SourceIndex(0) name (AbstractMode.getInitialState)
-7 >Emitted(61, 71) Source(67, 85) + SourceIndex(0) name (AbstractMode.getInitialState)
-8 >Emitted(61, 72) Source(67, 86) + SourceIndex(0) name (AbstractMode.getInitialState)
-9 >Emitted(61, 73) Source(67, 86) + SourceIndex(0) name (AbstractMode.getInitialState)
-10>Emitted(61, 74) Source(67, 87) + SourceIndex(0) name (AbstractMode.getInitialState)
+1->Emitted(60, 5) Source(67, 46) + SourceIndex(0) name (AbstractMode)
+2 >Emitted(60, 43) Source(67, 61) + SourceIndex(0) name (AbstractMode)
+3 >Emitted(60, 46) Source(67, 39) + SourceIndex(0) name (AbstractMode)
+4 >Emitted(60, 60) Source(67, 74) + SourceIndex(0) name (AbstractMode.getInitialState)
+5 >Emitted(60, 66) Source(67, 80) + SourceIndex(0) name (AbstractMode.getInitialState)
+6 >Emitted(60, 67) Source(67, 81) + SourceIndex(0) name (AbstractMode.getInitialState)
+7 >Emitted(60, 71) Source(67, 85) + SourceIndex(0) name (AbstractMode.getInitialState)
+8 >Emitted(60, 72) Source(67, 86) + SourceIndex(0) name (AbstractMode.getInitialState)
+9 >Emitted(60, 73) Source(67, 86) + SourceIndex(0) name (AbstractMode.getInitialState)
+10>Emitted(60, 74) Source(67, 87) + SourceIndex(0) name (AbstractMode.getInitialState)
 ---
 >>>    return AbstractMode;
 1 >^^^^
 2 >    ^^^^^^^^^^^^^^^^^^^
 1 > 
 2 >    }
-1 >Emitted(62, 5) Source(67, 88) + SourceIndex(0) name (AbstractMode)
-2 >Emitted(62, 24) Source(67, 89) + SourceIndex(0) name (AbstractMode)
+1 >Emitted(61, 5) Source(67, 88) + SourceIndex(0) name (AbstractMode)
+2 >Emitted(61, 24) Source(67, 89) + SourceIndex(0) name (AbstractMode)
 ---
 >>>})();
 1 >
@@ -1240,10 +1239,10 @@ sourceFile:recursiveClassReferenceTest.ts
 2 >}
 3 > 
 4 > class AbstractMode implements IMode { public getInitialState(): IState { return null;} }
-1 >Emitted(63, 1) Source(67, 88) + SourceIndex(0) name (AbstractMode)
-2 >Emitted(63, 2) Source(67, 89) + SourceIndex(0) name (AbstractMode)
-3 >Emitted(63, 2) Source(67, 1) + SourceIndex(0)
-4 >Emitted(63, 6) Source(67, 89) + SourceIndex(0)
+1 >Emitted(62, 1) Source(67, 88) + SourceIndex(0) name (AbstractMode)
+2 >Emitted(62, 2) Source(67, 89) + SourceIndex(0) name (AbstractMode)
+3 >Emitted(62, 2) Source(67, 1) + SourceIndex(0)
+4 >Emitted(62, 6) Source(67, 89) + SourceIndex(0)
 ---
 >>>var Sample;
 1->
@@ -1288,10 +1287,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >          
   >          	}
   >          }
-1->Emitted(64, 1) Source(76, 1) + SourceIndex(0)
-2 >Emitted(64, 5) Source(76, 8) + SourceIndex(0)
-3 >Emitted(64, 11) Source(76, 14) + SourceIndex(0)
-4 >Emitted(64, 12) Source(100, 2) + SourceIndex(0)
+1->Emitted(63, 1) Source(76, 1) + SourceIndex(0)
+2 >Emitted(63, 5) Source(76, 8) + SourceIndex(0)
+3 >Emitted(63, 11) Source(76, 14) + SourceIndex(0)
+4 >Emitted(63, 12) Source(100, 2) + SourceIndex(0)
 ---
 >>>(function (Sample) {
 1->
@@ -1300,9 +1299,9 @@ sourceFile:recursiveClassReferenceTest.ts
 1->
 2 >module 
 3 >           Sample
-1->Emitted(65, 1) Source(76, 1) + SourceIndex(0)
-2 >Emitted(65, 12) Source(76, 8) + SourceIndex(0)
-3 >Emitted(65, 18) Source(76, 14) + SourceIndex(0)
+1->Emitted(64, 1) Source(76, 1) + SourceIndex(0)
+2 >Emitted(64, 12) Source(76, 8) + SourceIndex(0)
+3 >Emitted(64, 18) Source(76, 14) + SourceIndex(0)
 ---
 >>>    var Thing;
 1 >^^^^
@@ -1338,10 +1337,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >             
   >             	}
   >             }
-1 >Emitted(66, 5) Source(76, 15) + SourceIndex(0) name (Sample)
-2 >Emitted(66, 9) Source(76, 15) + SourceIndex(0) name (Sample)
-3 >Emitted(66, 14) Source(76, 20) + SourceIndex(0) name (Sample)
-4 >Emitted(66, 15) Source(100, 2) + SourceIndex(0) name (Sample)
+1 >Emitted(65, 5) Source(76, 15) + SourceIndex(0) name (Sample)
+2 >Emitted(65, 9) Source(76, 15) + SourceIndex(0) name (Sample)
+3 >Emitted(65, 14) Source(76, 20) + SourceIndex(0) name (Sample)
+4 >Emitted(65, 15) Source(100, 2) + SourceIndex(0) name (Sample)
 ---
 >>>    (function (Thing) {
 1->^^^^
@@ -1351,9 +1350,9 @@ sourceFile:recursiveClassReferenceTest.ts
 1->
 2 >    
 3 >               Thing
-1->Emitted(67, 5) Source(76, 15) + SourceIndex(0) name (Sample)
-2 >Emitted(67, 16) Source(76, 15) + SourceIndex(0) name (Sample)
-3 >Emitted(67, 21) Source(76, 20) + SourceIndex(0) name (Sample)
+1->Emitted(66, 5) Source(76, 15) + SourceIndex(0) name (Sample)
+2 >Emitted(66, 16) Source(76, 15) + SourceIndex(0) name (Sample)
+3 >Emitted(66, 21) Source(76, 20) + SourceIndex(0) name (Sample)
 ---
 >>>        var Languages;
 1->^^^^^^^^
@@ -1389,10 +1388,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >                     
   >                     	}
   >                     }
-1->Emitted(68, 9) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
-2 >Emitted(68, 13) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
-3 >Emitted(68, 22) Source(76, 30) + SourceIndex(0) name (Sample.Thing)
-4 >Emitted(68, 23) Source(100, 2) + SourceIndex(0) name (Sample.Thing)
+1->Emitted(67, 9) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
+2 >Emitted(67, 13) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
+3 >Emitted(67, 22) Source(76, 30) + SourceIndex(0) name (Sample.Thing)
+4 >Emitted(67, 23) Source(100, 2) + SourceIndex(0) name (Sample.Thing)
 ---
 >>>        (function (Languages) {
 1->^^^^^^^^
@@ -1401,9 +1400,9 @@ sourceFile:recursiveClassReferenceTest.ts
 1->
 2 >        
 3 >                   Languages
-1->Emitted(69, 9) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
-2 >Emitted(69, 20) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
-3 >Emitted(69, 29) Source(76, 30) + SourceIndex(0) name (Sample.Thing)
+1->Emitted(68, 9) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
+2 >Emitted(68, 20) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
+3 >Emitted(68, 29) Source(76, 30) + SourceIndex(0) name (Sample.Thing)
 ---
 >>>            var PlainText;
 1 >^^^^^^^^^^^^
@@ -1439,10 +1438,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >                         
   >                         	}
   >                         }
-1 >Emitted(70, 13) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
-2 >Emitted(70, 17) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
-3 >Emitted(70, 26) Source(76, 40) + SourceIndex(0) name (Sample.Thing.Languages)
-4 >Emitted(70, 27) Source(100, 2) + SourceIndex(0) name (Sample.Thing.Languages)
+1 >Emitted(69, 13) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
+2 >Emitted(69, 17) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
+3 >Emitted(69, 26) Source(76, 40) + SourceIndex(0) name (Sample.Thing.Languages)
+4 >Emitted(69, 27) Source(100, 2) + SourceIndex(0) name (Sample.Thing.Languages)
 ---
 >>>            (function (PlainText) {
 1->^^^^^^^^^^^^
@@ -1456,11 +1455,11 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                       PlainText
 4 >                                 
 5 >                                  {
-1->Emitted(71, 13) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
-2 >Emitted(71, 24) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
-3 >Emitted(71, 33) Source(76, 40) + SourceIndex(0) name (Sample.Thing.Languages)
-4 >Emitted(71, 35) Source(76, 41) + SourceIndex(0) name (Sample.Thing.Languages)
-5 >Emitted(71, 36) Source(76, 42) + SourceIndex(0) name (Sample.Thing.Languages)
+1->Emitted(70, 13) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
+2 >Emitted(70, 24) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
+3 >Emitted(70, 33) Source(76, 40) + SourceIndex(0) name (Sample.Thing.Languages)
+4 >Emitted(70, 35) Source(76, 41) + SourceIndex(0) name (Sample.Thing.Languages)
+5 >Emitted(70, 36) Source(76, 42) + SourceIndex(0) name (Sample.Thing.Languages)
 ---
 >>>                var State = (function () {
 1->^^^^^^^^^^^^^^^^
@@ -1468,7 +1467,7 @@ sourceFile:recursiveClassReferenceTest.ts
 1->
   >	
   >	
-1->Emitted(72, 17) Source(78, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+1->Emitted(71, 17) Source(78, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
 ---
 >>>                    function State(mode) {
 1->^^^^^^^^^^^^^^^^^^^^
@@ -1479,9 +1478,9 @@ sourceFile:recursiveClassReferenceTest.ts
   >        
 2 >                    constructor(private 
 3 >                                   mode: IMode
-1->Emitted(73, 21) Source(79, 9) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-2 >Emitted(73, 36) Source(79, 29) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-3 >Emitted(73, 40) Source(79, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+1->Emitted(72, 21) Source(79, 9) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+2 >Emitted(72, 36) Source(79, 29) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+3 >Emitted(72, 40) Source(79, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
 ---
 >>>                        this.mode = mode;
 1->^^^^^^^^^^^^^^^^^^^^^^^^
@@ -1494,11 +1493,11 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                                 
 4 >                                    mode
 5 >                                        : IMode
-1->Emitted(74, 25) Source(79, 29) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
-2 >Emitted(74, 34) Source(79, 33) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
-3 >Emitted(74, 37) Source(79, 29) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
-4 >Emitted(74, 41) Source(79, 33) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
-5 >Emitted(74, 42) Source(79, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
+1->Emitted(73, 25) Source(79, 29) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
+2 >Emitted(73, 34) Source(79, 33) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
+3 >Emitted(73, 37) Source(79, 29) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
+4 >Emitted(73, 41) Source(79, 33) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
+5 >Emitted(73, 42) Source(79, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
 ---
 >>>                    }
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -1506,8 +1505,8 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >) { 
 2 >                    }
-1 >Emitted(75, 21) Source(79, 44) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
-2 >Emitted(75, 22) Source(79, 45) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
+1 >Emitted(74, 21) Source(79, 44) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
+2 >Emitted(74, 22) Source(79, 45) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.constructor)
 ---
 >>>                    State.prototype.clone = function () {
 1->^^^^^^^^^^^^^^^^^^^^
@@ -1517,9 +1516,9 @@ sourceFile:recursiveClassReferenceTest.ts
   >		public 
 2 >                    clone
 3 >                                         
-1->Emitted(76, 21) Source(80, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-2 >Emitted(76, 42) Source(80, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-3 >Emitted(76, 45) Source(80, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+1->Emitted(75, 21) Source(80, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+2 >Emitted(75, 42) Source(80, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+3 >Emitted(75, 45) Source(80, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
 ---
 >>>                        return this;
 1 >^^^^^^^^^^^^^^^^^^^^^^^^
@@ -1533,11 +1532,11 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                               
 4 >                               this
 5 >                                   ;
-1 >Emitted(77, 25) Source(81, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
-2 >Emitted(77, 31) Source(81, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
-3 >Emitted(77, 32) Source(81, 11) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
-4 >Emitted(77, 36) Source(81, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
-5 >Emitted(77, 37) Source(81, 16) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
+1 >Emitted(76, 25) Source(81, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
+2 >Emitted(76, 31) Source(81, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
+3 >Emitted(76, 32) Source(81, 11) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
+4 >Emitted(76, 36) Source(81, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
+5 >Emitted(76, 37) Source(81, 16) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
 ---
 >>>                    };
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -1546,8 +1545,8 @@ sourceFile:recursiveClassReferenceTest.ts
 1 >
   >		
 2 >                    }
-1 >Emitted(78, 21) Source(82, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
-2 >Emitted(78, 22) Source(82, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
+1 >Emitted(77, 21) Source(82, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
+2 >Emitted(77, 22) Source(82, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.clone)
 ---
 >>>                    State.prototype.equals = function (other) {
 1->^^^^^^^^^^^^^^^^^^^^
@@ -1562,11 +1561,11 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                                          
 4 >                                             public equals(
 5 >                                                       other:IState
-1->Emitted(79, 21) Source(84, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-2 >Emitted(79, 43) Source(84, 16) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-3 >Emitted(79, 46) Source(84, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-4 >Emitted(79, 56) Source(84, 17) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-5 >Emitted(79, 61) Source(84, 29) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+1->Emitted(78, 21) Source(84, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+2 >Emitted(78, 43) Source(84, 16) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+3 >Emitted(78, 46) Source(84, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+4 >Emitted(78, 56) Source(84, 17) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+5 >Emitted(78, 61) Source(84, 29) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
 ---
 >>>                        return this === other;
 1 >^^^^^^^^^^^^^^^^^^^^^^^^
@@ -1584,13 +1583,13 @@ sourceFile:recursiveClassReferenceTest.ts
 5 >                                    === 
 6 >                                        other
 7 >                                             ;
-1 >Emitted(80, 25) Source(85, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
-2 >Emitted(80, 31) Source(85, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
-3 >Emitted(80, 32) Source(85, 11) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
-4 >Emitted(80, 36) Source(85, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
-5 >Emitted(80, 41) Source(85, 20) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
-6 >Emitted(80, 46) Source(85, 25) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
-7 >Emitted(80, 47) Source(85, 26) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
+1 >Emitted(79, 25) Source(85, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
+2 >Emitted(79, 31) Source(85, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
+3 >Emitted(79, 32) Source(85, 11) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
+4 >Emitted(79, 36) Source(85, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
+5 >Emitted(79, 41) Source(85, 20) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
+6 >Emitted(79, 46) Source(85, 25) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
+7 >Emitted(79, 47) Source(85, 26) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
 ---
 >>>                    };
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -1599,8 +1598,8 @@ sourceFile:recursiveClassReferenceTest.ts
 1 >
   >		
 2 >                    }
-1 >Emitted(81, 21) Source(86, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
-2 >Emitted(81, 22) Source(86, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
+1 >Emitted(80, 21) Source(86, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
+2 >Emitted(80, 22) Source(86, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.equals)
 ---
 >>>                    State.prototype.getMode = function () { return mode; };
 1->^^^^^^^^^^^^^^^^^^^^
@@ -1625,16 +1624,16 @@ sourceFile:recursiveClassReferenceTest.ts
 8 >                                                                       ;
 9 >                                                                         
 10>                                                                         }
-1->Emitted(82, 21) Source(88, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-2 >Emitted(82, 44) Source(88, 17) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-3 >Emitted(82, 47) Source(88, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-4 >Emitted(82, 61) Source(88, 29) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
-5 >Emitted(82, 67) Source(88, 35) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
-6 >Emitted(82, 68) Source(88, 36) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
-7 >Emitted(82, 72) Source(88, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
-8 >Emitted(82, 73) Source(88, 41) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
-9 >Emitted(82, 74) Source(88, 42) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
-10>Emitted(82, 75) Source(88, 43) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
+1->Emitted(81, 21) Source(88, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+2 >Emitted(81, 44) Source(88, 17) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+3 >Emitted(81, 47) Source(88, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+4 >Emitted(81, 61) Source(88, 29) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
+5 >Emitted(81, 67) Source(88, 35) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
+6 >Emitted(81, 68) Source(88, 36) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
+7 >Emitted(81, 72) Source(88, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
+8 >Emitted(81, 73) Source(88, 41) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
+9 >Emitted(81, 74) Source(88, 42) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
+10>Emitted(81, 75) Source(88, 43) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State.getMode)
 ---
 >>>                    return State;
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -1642,8 +1641,8 @@ sourceFile:recursiveClassReferenceTest.ts
 1 >
   >	
 2 >                    }
-1 >Emitted(83, 21) Source(89, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-2 >Emitted(83, 33) Source(89, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+1 >Emitted(82, 21) Source(89, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+2 >Emitted(82, 33) Source(89, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
 ---
 >>>                })();
 1 >^^^^^^^^^^^^^^^^
@@ -1666,10 +1665,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >                 		
   >                 		public getMode(): IMode { return mode; }
   >                 	}
-1 >Emitted(84, 17) Source(89, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-2 >Emitted(84, 18) Source(89, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
-3 >Emitted(84, 18) Source(78, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-4 >Emitted(84, 22) Source(89, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+1 >Emitted(83, 17) Source(89, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+2 >Emitted(83, 18) Source(89, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.State)
+3 >Emitted(83, 18) Source(78, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+4 >Emitted(83, 22) Source(89, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
 ---
 >>>                PlainText.State = State;
 1->^^^^^^^^^^^^^^^^
@@ -1692,10 +1691,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >                               		public getMode(): IMode { return mode; }
   >                               	}
 4 >                                       
-1->Emitted(85, 17) Source(78, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-2 >Emitted(85, 32) Source(78, 20) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-3 >Emitted(85, 40) Source(89, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-4 >Emitted(85, 41) Source(89, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+1->Emitted(84, 17) Source(78, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+2 >Emitted(84, 32) Source(78, 20) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+3 >Emitted(84, 40) Source(89, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+4 >Emitted(84, 41) Source(89, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
 ---
 >>>                var Mode = (function (_super) {
 1->^^^^^^^^^^^^^^^^
@@ -1703,29 +1702,29 @@ sourceFile:recursiveClassReferenceTest.ts
 1->
   >	
   >	
-1->Emitted(86, 17) Source(91, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+1->Emitted(85, 17) Source(91, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
 ---
 >>>                    __extends(Mode, _super);
 1->^^^^^^^^^^^^^^^^^^^^
 2 >                    ^^^^^^^^^^^^^^^^^^^^^^^^
 1->export class Mode extends 
 2 >                    AbstractMode
-1->Emitted(87, 21) Source(91, 28) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
-2 >Emitted(87, 45) Source(91, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+1->Emitted(86, 21) Source(91, 28) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+2 >Emitted(86, 45) Source(91, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
 ---
 >>>                    function Mode() {
 1 >^^^^^^^^^^^^^^^^^^^^
 2 >                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
-1 >Emitted(88, 21) Source(91, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+1 >Emitted(87, 21) Source(91, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
 ---
 >>>                        _super.apply(this, arguments);
 1->^^^^^^^^^^^^^^^^^^^^^^^^
 2 >                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 1->export class Mode extends 
 2 >                        AbstractMode
-1->Emitted(89, 25) Source(91, 28) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.constructor)
-2 >Emitted(89, 55) Source(91, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.constructor)
+1->Emitted(88, 25) Source(91, 28) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.constructor)
+2 >Emitted(88, 55) Source(91, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.constructor)
 ---
 >>>                    }
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -1741,8 +1740,8 @@ sourceFile:recursiveClassReferenceTest.ts
   >
   >	
 2 >                    }
-1 >Emitted(90, 21) Source(99, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.constructor)
-2 >Emitted(90, 22) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.constructor)
+1 >Emitted(89, 21) Source(99, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.constructor)
+2 >Emitted(89, 22) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.constructor)
 ---
 >>>                    // scenario 2
 1->^^^^^^^^^^^^^^^^^^^^
@@ -1750,8 +1749,8 @@ sourceFile:recursiveClassReferenceTest.ts
 3 >                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1->
 2 >                    // scenario 2
-1->Emitted(91, 21) Source(93, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
-2 >Emitted(91, 34) Source(93, 16) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+1->Emitted(90, 21) Source(93, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+2 >Emitted(90, 34) Source(93, 16) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
 ---
 >>>                    Mode.prototype.getInitialState = function () {
 1->^^^^^^^^^^^^^^^^^^^^
@@ -1761,9 +1760,9 @@ sourceFile:recursiveClassReferenceTest.ts
   >		public 
 2 >                    getInitialState
 3 >                                                  
-1->Emitted(92, 21) Source(94, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
-2 >Emitted(92, 51) Source(94, 25) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
-3 >Emitted(92, 54) Source(94, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+1->Emitted(91, 21) Source(94, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+2 >Emitted(91, 51) Source(94, 25) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+3 >Emitted(91, 54) Source(94, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
 ---
 >>>                        return new State(self);
 1 >^^^^^^^^^^^^^^^^^^^^^^^^
@@ -1785,15 +1784,15 @@ sourceFile:recursiveClassReferenceTest.ts
 7 >                                         self
 8 >                                             )
 9 >                                              ;
-1 >Emitted(93, 25) Source(95, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
-2 >Emitted(93, 31) Source(95, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
-3 >Emitted(93, 32) Source(95, 11) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
-4 >Emitted(93, 36) Source(95, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
-5 >Emitted(93, 41) Source(95, 20) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
-6 >Emitted(93, 42) Source(95, 21) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
-7 >Emitted(93, 46) Source(95, 25) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
-8 >Emitted(93, 47) Source(95, 26) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
-9 >Emitted(93, 48) Source(95, 27) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
+1 >Emitted(92, 25) Source(95, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
+2 >Emitted(92, 31) Source(95, 10) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
+3 >Emitted(92, 32) Source(95, 11) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
+4 >Emitted(92, 36) Source(95, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
+5 >Emitted(92, 41) Source(95, 20) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
+6 >Emitted(92, 42) Source(95, 21) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
+7 >Emitted(92, 46) Source(95, 25) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
+8 >Emitted(92, 47) Source(95, 26) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
+9 >Emitted(92, 48) Source(95, 27) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
 ---
 >>>                    };
 1 >^^^^^^^^^^^^^^^^^^^^
@@ -1802,8 +1801,8 @@ sourceFile:recursiveClassReferenceTest.ts
 1 >
   >		
 2 >                    }
-1 >Emitted(94, 21) Source(96, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
-2 >Emitted(94, 22) Source(96, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
+1 >Emitted(93, 21) Source(96, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
+2 >Emitted(93, 22) Source(96, 4) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode.getInitialState)
 ---
 >>>                    return Mode;
 1->^^^^^^^^^^^^^^^^^^^^
@@ -1814,8 +1813,8 @@ sourceFile:recursiveClassReferenceTest.ts
   >
   >	
 2 >                    }
-1->Emitted(95, 21) Source(99, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
-2 >Emitted(95, 32) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+1->Emitted(94, 21) Source(99, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+2 >Emitted(94, 32) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
 ---
 >>>                })(AbstractMode);
 1->^^^^^^^^^^^^^^^^
@@ -1839,12 +1838,12 @@ sourceFile:recursiveClassReferenceTest.ts
   >                               
   >                               
   >                               	}
-1->Emitted(96, 17) Source(99, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
-2 >Emitted(96, 18) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
-3 >Emitted(96, 18) Source(91, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-4 >Emitted(96, 20) Source(91, 28) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-5 >Emitted(96, 32) Source(91, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-6 >Emitted(96, 34) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+1->Emitted(95, 17) Source(99, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+2 >Emitted(95, 18) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText.Mode)
+3 >Emitted(95, 18) Source(91, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+4 >Emitted(95, 20) Source(91, 28) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+5 >Emitted(95, 32) Source(91, 40) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+6 >Emitted(95, 34) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
 ---
 >>>                PlainText.Mode = Mode;
 1->^^^^^^^^^^^^^^^^
@@ -1864,10 +1863,10 @@ sourceFile:recursiveClassReferenceTest.ts
   >                              
   >                              	}
 4 >                                     
-1->Emitted(97, 17) Source(91, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-2 >Emitted(97, 31) Source(91, 19) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-3 >Emitted(97, 38) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-4 >Emitted(97, 39) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+1->Emitted(96, 17) Source(91, 15) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+2 >Emitted(96, 31) Source(91, 19) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+3 >Emitted(96, 38) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+4 >Emitted(96, 39) Source(99, 3) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
 ---
 >>>            })(PlainText = Languages.PlainText || (Languages.PlainText = {}));
 1->^^^^^^^^^^^^
@@ -1913,15 +1912,15 @@ sourceFile:recursiveClassReferenceTest.ts
   >                                                                      
   >                                                                      	}
   >                                                                      }
-1->Emitted(98, 13) Source(100, 1) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-2 >Emitted(98, 14) Source(100, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
-3 >Emitted(98, 16) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
-4 >Emitted(98, 25) Source(76, 40) + SourceIndex(0) name (Sample.Thing.Languages)
-5 >Emitted(98, 28) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
-6 >Emitted(98, 47) Source(76, 40) + SourceIndex(0) name (Sample.Thing.Languages)
-7 >Emitted(98, 52) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
-8 >Emitted(98, 71) Source(76, 40) + SourceIndex(0) name (Sample.Thing.Languages)
-9 >Emitted(98, 79) Source(100, 2) + SourceIndex(0) name (Sample.Thing.Languages)
+1->Emitted(97, 13) Source(100, 1) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+2 >Emitted(97, 14) Source(100, 2) + SourceIndex(0) name (Sample.Thing.Languages.PlainText)
+3 >Emitted(97, 16) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
+4 >Emitted(97, 25) Source(76, 40) + SourceIndex(0) name (Sample.Thing.Languages)
+5 >Emitted(97, 28) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
+6 >Emitted(97, 47) Source(76, 40) + SourceIndex(0) name (Sample.Thing.Languages)
+7 >Emitted(97, 52) Source(76, 31) + SourceIndex(0) name (Sample.Thing.Languages)
+8 >Emitted(97, 71) Source(76, 40) + SourceIndex(0) name (Sample.Thing.Languages)
+9 >Emitted(97, 79) Source(100, 2) + SourceIndex(0) name (Sample.Thing.Languages)
 ---
 >>>        })(Languages = Thing.Languages || (Thing.Languages = {}));
 1 >^^^^^^^^
@@ -1966,15 +1965,15 @@ sourceFile:recursiveClassReferenceTest.ts
   >                                                          
   >                                                          	}
   >                                                          }
-1 >Emitted(99, 9) Source(100, 1) + SourceIndex(0) name (Sample.Thing.Languages)
-2 >Emitted(99, 10) Source(100, 2) + SourceIndex(0) name (Sample.Thing.Languages)
-3 >Emitted(99, 12) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
-4 >Emitted(99, 21) Source(76, 30) + SourceIndex(0) name (Sample.Thing)
-5 >Emitted(99, 24) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
-6 >Emitted(99, 39) Source(76, 30) + SourceIndex(0) name (Sample.Thing)
-7 >Emitted(99, 44) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
-8 >Emitted(99, 59) Source(76, 30) + SourceIndex(0) name (Sample.Thing)
-9 >Emitted(99, 67) Source(100, 2) + SourceIndex(0) name (Sample.Thing)
+1 >Emitted(98, 9) Source(100, 1) + SourceIndex(0) name (Sample.Thing.Languages)
+2 >Emitted(98, 10) Source(100, 2) + SourceIndex(0) name (Sample.Thing.Languages)
+3 >Emitted(98, 12) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
+4 >Emitted(98, 21) Source(76, 30) + SourceIndex(0) name (Sample.Thing)
+5 >Emitted(98, 24) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
+6 >Emitted(98, 39) Source(76, 30) + SourceIndex(0) name (Sample.Thing)
+7 >Emitted(98, 44) Source(76, 21) + SourceIndex(0) name (Sample.Thing)
+8 >Emitted(98, 59) Source(76, 30) + SourceIndex(0) name (Sample.Thing)
+9 >Emitted(98, 67) Source(100, 2) + SourceIndex(0) name (Sample.Thing)
 ---
 >>>    })(Thing = Sample.Thing || (Sample.Thing = {}));
 1 >^^^^
@@ -2019,15 +2018,15 @@ sourceFile:recursiveClassReferenceTest.ts
   >                                            
   >                                            	}
   >                                            }
-1 >Emitted(100, 5) Source(100, 1) + SourceIndex(0) name (Sample.Thing)
-2 >Emitted(100, 6) Source(100, 2) + SourceIndex(0) name (Sample.Thing)
-3 >Emitted(100, 8) Source(76, 15) + SourceIndex(0) name (Sample)
-4 >Emitted(100, 13) Source(76, 20) + SourceIndex(0) name (Sample)
-5 >Emitted(100, 16) Source(76, 15) + SourceIndex(0) name (Sample)
-6 >Emitted(100, 28) Source(76, 20) + SourceIndex(0) name (Sample)
-7 >Emitted(100, 33) Source(76, 15) + SourceIndex(0) name (Sample)
-8 >Emitted(100, 45) Source(76, 20) + SourceIndex(0) name (Sample)
-9 >Emitted(100, 53) Source(100, 2) + SourceIndex(0) name (Sample)
+1 >Emitted(99, 5) Source(100, 1) + SourceIndex(0) name (Sample.Thing)
+2 >Emitted(99, 6) Source(100, 2) + SourceIndex(0) name (Sample.Thing)
+3 >Emitted(99, 8) Source(76, 15) + SourceIndex(0) name (Sample)
+4 >Emitted(99, 13) Source(76, 20) + SourceIndex(0) name (Sample)
+5 >Emitted(99, 16) Source(76, 15) + SourceIndex(0) name (Sample)
+6 >Emitted(99, 28) Source(76, 20) + SourceIndex(0) name (Sample)
+7 >Emitted(99, 33) Source(76, 15) + SourceIndex(0) name (Sample)
+8 >Emitted(99, 45) Source(76, 20) + SourceIndex(0) name (Sample)
+9 >Emitted(99, 53) Source(100, 2) + SourceIndex(0) name (Sample)
 ---
 >>>})(Sample || (Sample = {}));
 1 >
@@ -2069,12 +2068,12 @@ sourceFile:recursiveClassReferenceTest.ts
   >                    
   >                    	}
   >                    }
-1 >Emitted(101, 1) Source(100, 1) + SourceIndex(0) name (Sample)
-2 >Emitted(101, 2) Source(100, 2) + SourceIndex(0) name (Sample)
-3 >Emitted(101, 4) Source(76, 8) + SourceIndex(0)
-4 >Emitted(101, 10) Source(76, 14) + SourceIndex(0)
-5 >Emitted(101, 15) Source(76, 8) + SourceIndex(0)
-6 >Emitted(101, 21) Source(76, 14) + SourceIndex(0)
-7 >Emitted(101, 29) Source(100, 2) + SourceIndex(0)
+1 >Emitted(100, 1) Source(100, 1) + SourceIndex(0) name (Sample)
+2 >Emitted(100, 2) Source(100, 2) + SourceIndex(0) name (Sample)
+3 >Emitted(100, 4) Source(76, 8) + SourceIndex(0)
+4 >Emitted(100, 10) Source(76, 14) + SourceIndex(0)
+5 >Emitted(100, 15) Source(76, 8) + SourceIndex(0)
+6 >Emitted(100, 21) Source(76, 14) + SourceIndex(0)
+7 >Emitted(100, 29) Source(100, 2) + SourceIndex(0)
 ---
 >>>//# sourceMappingURL=recursiveClassReferenceTest.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/recursiveComplicatedClasses.js b/tests/baselines/reference/recursiveComplicatedClasses.js
index 6e88dd8dc22..e35931008b2 100644
--- a/tests/baselines/reference/recursiveComplicatedClasses.js
+++ b/tests/baselines/reference/recursiveComplicatedClasses.js
@@ -28,8 +28,7 @@ class TypeSymbol extends InferenceSymbol {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Signature = (function () {
     function Signature() {
diff --git a/tests/baselines/reference/recursivelySpecializedConstructorDeclaration.js b/tests/baselines/reference/recursivelySpecializedConstructorDeclaration.js
index 60022dc245a..48e8b1c4eba 100644
--- a/tests/baselines/reference/recursivelySpecializedConstructorDeclaration.js
+++ b/tests/baselines/reference/recursivelySpecializedConstructorDeclaration.js
@@ -33,8 +33,7 @@ declare module MsPortal.Controls.Base.ItemList {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var MsPortal;
 (function (MsPortal) {
diff --git a/tests/baselines/reference/resolvingClassDeclarationWhenInBaseTypeResolution.js b/tests/baselines/reference/resolvingClassDeclarationWhenInBaseTypeResolution.js
index 72cc702309c..3ba03a1e03c 100644
--- a/tests/baselines/reference/resolvingClassDeclarationWhenInBaseTypeResolution.js
+++ b/tests/baselines/reference/resolvingClassDeclarationWhenInBaseTypeResolution.js
@@ -1023,8 +1023,7 @@ module caurinus {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var rionegrensis;
 (function (rionegrensis) {
diff --git a/tests/baselines/reference/returnInConstructor1.js b/tests/baselines/reference/returnInConstructor1.js
index 87b1b6d672a..e8781f06d24 100644
--- a/tests/baselines/reference/returnInConstructor1.js
+++ b/tests/baselines/reference/returnInConstructor1.js
@@ -70,8 +70,7 @@ class I extends G {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/returnStatements.js b/tests/baselines/reference/returnStatements.js
index 35c208b19ee..956efc5f077 100644
--- a/tests/baselines/reference/returnStatements.js
+++ b/tests/baselines/reference/returnStatements.js
@@ -28,8 +28,7 @@ function fn13(): C { return null; }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // all the following should be valid
 function fn1() { return 1; }
diff --git a/tests/baselines/reference/scopeCheckExtendedClassInsidePublicMethod2.js b/tests/baselines/reference/scopeCheckExtendedClassInsidePublicMethod2.js
index f971f089741..1a5fc7d9b3e 100644
--- a/tests/baselines/reference/scopeCheckExtendedClassInsidePublicMethod2.js
+++ b/tests/baselines/reference/scopeCheckExtendedClassInsidePublicMethod2.js
@@ -12,8 +12,7 @@ class D extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/scopeCheckExtendedClassInsideStaticMethod1.js b/tests/baselines/reference/scopeCheckExtendedClassInsideStaticMethod1.js
index a7f7f4fde99..2844897bdd9 100644
--- a/tests/baselines/reference/scopeCheckExtendedClassInsideStaticMethod1.js
+++ b/tests/baselines/reference/scopeCheckExtendedClassInsideStaticMethod1.js
@@ -12,8 +12,7 @@ class D extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/scopeTests.js b/tests/baselines/reference/scopeTests.js
index 99a933cf157..b104f63f74c 100644
--- a/tests/baselines/reference/scopeTests.js
+++ b/tests/baselines/reference/scopeTests.js
@@ -15,8 +15,7 @@ class D extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/shadowPrivateMembers.js b/tests/baselines/reference/shadowPrivateMembers.js
index 4100dba13e3..e2ac679e7eb 100644
--- a/tests/baselines/reference/shadowPrivateMembers.js
+++ b/tests/baselines/reference/shadowPrivateMembers.js
@@ -7,8 +7,7 @@ class derived extends base { private n() {} }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var base = (function () {
     function base() {
diff --git a/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js b/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js
index cae6e991e24..f210e65d4d2 100644
--- a/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js
+++ b/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js
@@ -11,8 +11,7 @@ class Greeter extends AbstractGreeter {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var AbstractGreeter = (function () {
     function AbstractGreeter() {
diff --git a/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js.map b/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js.map
index 60a26845043..fad366e8ebb 100644
--- a/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js.map
+++ b/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js.map
@@ -1,2 +1,2 @@
 //// [sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js.map]
-{"version":3,"file":"sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js","sourceRoot":"","sources":["sourceMapValidationClassWithDefaultConstructorAndExtendsClause.ts"],"names":["AbstractGreeter","AbstractGreeter.constructor","Greeter","Greeter.constructor"],"mappings":";;;;;;AAAA;IAAAA;IACAC,CAACA;IAADD,sBAACA;AAADA,CAACA,AADD,IACC;AAED;IAAsBE,2BAAeA;IAArCA;QAAsBC,8BAAeA;QAC1BA,MAACA,GAAGA,EAAEA,CAACA;QACPA,UAAKA,GAAGA,KAAKA,CAACA;IACzBA,CAACA;IAADD,cAACA;AAADA,CAACA,AAHD,EAAsB,eAAe,EAGpC"}
\ No newline at end of file
+{"version":3,"file":"sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js","sourceRoot":"","sources":["sourceMapValidationClassWithDefaultConstructorAndExtendsClause.ts"],"names":["AbstractGreeter","AbstractGreeter.constructor","Greeter","Greeter.constructor"],"mappings":";;;;;AAAA;IAAAA;IACAC,CAACA;IAADD,sBAACA;AAADA,CAACA,AADD,IACC;AAED;IAAsBE,2BAAeA;IAArCA;QAAsBC,8BAAeA;QAC1BA,MAACA,GAAGA,EAAEA,CAACA;QACPA,UAAKA,GAAGA,KAAKA,CAACA;IACzBA,CAACA;IAADD,cAACA;AAADA,CAACA,AAHD,EAAsB,eAAe,EAGpC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.sourcemap.txt b/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.sourcemap.txt
index d0934f3c9ed..aba9861a230 100644
--- a/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.sourcemap.txt
+++ b/tests/baselines/reference/sourceMapValidationClassWithDefaultConstructorAndExtendsClause.sourcemap.txt
@@ -11,20 +11,19 @@ sourceFile:sourceMapValidationClassWithDefaultConstructorAndExtendsClause.ts
 >>>var __extends = (this && this.__extends) || function (d, b) {
 >>>    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
 >>>    function __() { this.constructor = d; }
->>>    __.prototype = b.prototype;
->>>    d.prototype = new __();
+>>>    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 >>>};
 >>>var AbstractGreeter = (function () {
 1 >
 2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
-1 >Emitted(7, 1) Source(1, 1) + SourceIndex(0)
+1 >Emitted(6, 1) Source(1, 1) + SourceIndex(0)
 ---
 >>>    function AbstractGreeter() {
 1->^^^^
 2 >    ^^->
 1->
-1->Emitted(8, 5) Source(1, 1) + SourceIndex(0) name (AbstractGreeter)
+1->Emitted(7, 5) Source(1, 1) + SourceIndex(0) name (AbstractGreeter)
 ---
 >>>    }
 1->^^^^
@@ -33,16 +32,16 @@ sourceFile:sourceMapValidationClassWithDefaultConstructorAndExtendsClause.ts
 1->class AbstractGreeter {
   >
 2 >    }
-1->Emitted(9, 5) Source(2, 1) + SourceIndex(0) name (AbstractGreeter.constructor)
-2 >Emitted(9, 6) Source(2, 2) + SourceIndex(0) name (AbstractGreeter.constructor)
+1->Emitted(8, 5) Source(2, 1) + SourceIndex(0) name (AbstractGreeter.constructor)
+2 >Emitted(8, 6) Source(2, 2) + SourceIndex(0) name (AbstractGreeter.constructor)
 ---
 >>>    return AbstractGreeter;
 1->^^^^
 2 >    ^^^^^^^^^^^^^^^^^^^^^^
 1->
 2 >    }
-1->Emitted(10, 5) Source(2, 1) + SourceIndex(0) name (AbstractGreeter)
-2 >Emitted(10, 27) Source(2, 2) + SourceIndex(0) name (AbstractGreeter)
+1->Emitted(9, 5) Source(2, 1) + SourceIndex(0) name (AbstractGreeter)
+2 >Emitted(9, 27) Source(2, 2) + SourceIndex(0) name (AbstractGreeter)
 ---
 >>>})();
 1 >
@@ -55,10 +54,10 @@ sourceFile:sourceMapValidationClassWithDefaultConstructorAndExtendsClause.ts
 3 > 
 4 > class AbstractGreeter {
   > }
-1 >Emitted(11, 1) Source(2, 1) + SourceIndex(0) name (AbstractGreeter)
-2 >Emitted(11, 2) Source(2, 2) + SourceIndex(0) name (AbstractGreeter)
-3 >Emitted(11, 2) Source(1, 1) + SourceIndex(0)
-4 >Emitted(11, 6) Source(2, 2) + SourceIndex(0)
+1 >Emitted(10, 1) Source(2, 1) + SourceIndex(0) name (AbstractGreeter)
+2 >Emitted(10, 2) Source(2, 2) + SourceIndex(0) name (AbstractGreeter)
+3 >Emitted(10, 2) Source(1, 1) + SourceIndex(0)
+4 >Emitted(10, 6) Source(2, 2) + SourceIndex(0)
 ---
 >>>var Greeter = (function (_super) {
 1->
@@ -66,29 +65,29 @@ sourceFile:sourceMapValidationClassWithDefaultConstructorAndExtendsClause.ts
 1->
   >
   >
-1->Emitted(12, 1) Source(4, 1) + SourceIndex(0)
+1->Emitted(11, 1) Source(4, 1) + SourceIndex(0)
 ---
 >>>    __extends(Greeter, _super);
 1->^^^^
 2 >    ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 1->class Greeter extends 
 2 >    AbstractGreeter
-1->Emitted(13, 5) Source(4, 23) + SourceIndex(0) name (Greeter)
-2 >Emitted(13, 32) Source(4, 38) + SourceIndex(0) name (Greeter)
+1->Emitted(12, 5) Source(4, 23) + SourceIndex(0) name (Greeter)
+2 >Emitted(12, 32) Source(4, 38) + SourceIndex(0) name (Greeter)
 ---
 >>>    function Greeter() {
 1 >^^^^
 2 >    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
-1 >Emitted(14, 5) Source(4, 1) + SourceIndex(0) name (Greeter)
+1 >Emitted(13, 5) Source(4, 1) + SourceIndex(0) name (Greeter)
 ---
 >>>        _super.apply(this, arguments);
 1->^^^^^^^^
 2 >        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 1->class Greeter extends 
 2 >        AbstractGreeter
-1->Emitted(15, 9) Source(4, 23) + SourceIndex(0) name (Greeter.constructor)
-2 >Emitted(15, 39) Source(4, 38) + SourceIndex(0) name (Greeter.constructor)
+1->Emitted(14, 9) Source(4, 23) + SourceIndex(0) name (Greeter.constructor)
+2 >Emitted(14, 39) Source(4, 38) + SourceIndex(0) name (Greeter.constructor)
 ---
 >>>        this.a = 10;
 1 >^^^^^^^^
@@ -103,11 +102,11 @@ sourceFile:sourceMapValidationClassWithDefaultConstructorAndExtendsClause.ts
 3 >               = 
 4 >                 10
 5 >                   ;
-1 >Emitted(16, 9) Source(5, 12) + SourceIndex(0) name (Greeter.constructor)
-2 >Emitted(16, 15) Source(5, 13) + SourceIndex(0) name (Greeter.constructor)
-3 >Emitted(16, 18) Source(5, 16) + SourceIndex(0) name (Greeter.constructor)
-4 >Emitted(16, 20) Source(5, 18) + SourceIndex(0) name (Greeter.constructor)
-5 >Emitted(16, 21) Source(5, 19) + SourceIndex(0) name (Greeter.constructor)
+1 >Emitted(15, 9) Source(5, 12) + SourceIndex(0) name (Greeter.constructor)
+2 >Emitted(15, 15) Source(5, 13) + SourceIndex(0) name (Greeter.constructor)
+3 >Emitted(15, 18) Source(5, 16) + SourceIndex(0) name (Greeter.constructor)
+4 >Emitted(15, 20) Source(5, 18) + SourceIndex(0) name (Greeter.constructor)
+5 >Emitted(15, 21) Source(5, 19) + SourceIndex(0) name (Greeter.constructor)
 ---
 >>>        this.nameA = "Ten";
 1->^^^^^^^^
@@ -121,11 +120,11 @@ sourceFile:sourceMapValidationClassWithDefaultConstructorAndExtendsClause.ts
 3 >                   = 
 4 >                     "Ten"
 5 >                          ;
-1->Emitted(17, 9) Source(6, 12) + SourceIndex(0) name (Greeter.constructor)
-2 >Emitted(17, 19) Source(6, 17) + SourceIndex(0) name (Greeter.constructor)
-3 >Emitted(17, 22) Source(6, 20) + SourceIndex(0) name (Greeter.constructor)
-4 >Emitted(17, 27) Source(6, 25) + SourceIndex(0) name (Greeter.constructor)
-5 >Emitted(17, 28) Source(6, 26) + SourceIndex(0) name (Greeter.constructor)
+1->Emitted(16, 9) Source(6, 12) + SourceIndex(0) name (Greeter.constructor)
+2 >Emitted(16, 19) Source(6, 17) + SourceIndex(0) name (Greeter.constructor)
+3 >Emitted(16, 22) Source(6, 20) + SourceIndex(0) name (Greeter.constructor)
+4 >Emitted(16, 27) Source(6, 25) + SourceIndex(0) name (Greeter.constructor)
+5 >Emitted(16, 28) Source(6, 26) + SourceIndex(0) name (Greeter.constructor)
 ---
 >>>    }
 1 >^^^^
@@ -134,8 +133,8 @@ sourceFile:sourceMapValidationClassWithDefaultConstructorAndExtendsClause.ts
 1 >
   >
 2 >    }
-1 >Emitted(18, 5) Source(7, 1) + SourceIndex(0) name (Greeter.constructor)
-2 >Emitted(18, 6) Source(7, 2) + SourceIndex(0) name (Greeter.constructor)
+1 >Emitted(17, 5) Source(7, 1) + SourceIndex(0) name (Greeter.constructor)
+2 >Emitted(17, 6) Source(7, 2) + SourceIndex(0) name (Greeter.constructor)
 ---
 >>>    return Greeter;
 1->^^^^
@@ -143,8 +142,8 @@ sourceFile:sourceMapValidationClassWithDefaultConstructorAndExtendsClause.ts
 3 >                  ^^^->
 1->
 2 >    }
-1->Emitted(19, 5) Source(7, 1) + SourceIndex(0) name (Greeter)
-2 >Emitted(19, 19) Source(7, 2) + SourceIndex(0) name (Greeter)
+1->Emitted(18, 5) Source(7, 1) + SourceIndex(0) name (Greeter)
+2 >Emitted(18, 19) Source(7, 2) + SourceIndex(0) name (Greeter)
 ---
 >>>})(AbstractGreeter);
 1->
@@ -163,11 +162,11 @@ sourceFile:sourceMapValidationClassWithDefaultConstructorAndExtendsClause.ts
   >                      public a = 10;
   >                      public nameA = "Ten";
   >                  }
-1->Emitted(20, 1) Source(7, 1) + SourceIndex(0) name (Greeter)
-2 >Emitted(20, 2) Source(7, 2) + SourceIndex(0) name (Greeter)
-3 >Emitted(20, 2) Source(4, 1) + SourceIndex(0)
-4 >Emitted(20, 4) Source(4, 23) + SourceIndex(0)
-5 >Emitted(20, 19) Source(4, 38) + SourceIndex(0)
-6 >Emitted(20, 21) Source(7, 2) + SourceIndex(0)
+1->Emitted(19, 1) Source(7, 1) + SourceIndex(0) name (Greeter)
+2 >Emitted(19, 2) Source(7, 2) + SourceIndex(0) name (Greeter)
+3 >Emitted(19, 2) Source(4, 1) + SourceIndex(0)
+4 >Emitted(19, 4) Source(4, 23) + SourceIndex(0)
+5 >Emitted(19, 19) Source(4, 38) + SourceIndex(0)
+6 >Emitted(19, 21) Source(7, 2) + SourceIndex(0)
 ---
 >>>//# sourceMappingURL=sourceMapValidationClassWithDefaultConstructorAndExtendsClause.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/specializedInheritedConstructors1.js b/tests/baselines/reference/specializedInheritedConstructors1.js
index ec467ad9877..20ef13c3f09 100644
--- a/tests/baselines/reference/specializedInheritedConstructors1.js
+++ b/tests/baselines/reference/specializedInheritedConstructors1.js
@@ -21,8 +21,7 @@ var myView = new MyView(m); // was error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var View = (function () {
     function View(options) {
diff --git a/tests/baselines/reference/specializedOverloadWithRestParameters.js b/tests/baselines/reference/specializedOverloadWithRestParameters.js
index 2a022cdf7da..31cb4a69594 100644
--- a/tests/baselines/reference/specializedOverloadWithRestParameters.js
+++ b/tests/baselines/reference/specializedOverloadWithRestParameters.js
@@ -16,8 +16,7 @@ function g(tagName: any): Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/staticFactory1.js b/tests/baselines/reference/staticFactory1.js
index 96303af586f..03092a16de9 100644
--- a/tests/baselines/reference/staticFactory1.js
+++ b/tests/baselines/reference/staticFactory1.js
@@ -17,8 +17,7 @@ d.foo();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/staticInheritance.js b/tests/baselines/reference/staticInheritance.js
index 0aba29b3560..d3e14d482cc 100644
--- a/tests/baselines/reference/staticInheritance.js
+++ b/tests/baselines/reference/staticInheritance.js
@@ -15,8 +15,7 @@ doThing(B); //OK
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function doThing(x) { }
 var A = (function () {
diff --git a/tests/baselines/reference/staticMemberAccessOffDerivedType1.js b/tests/baselines/reference/staticMemberAccessOffDerivedType1.js
index ab3c010d571..8f9849af057 100644
--- a/tests/baselines/reference/staticMemberAccessOffDerivedType1.js
+++ b/tests/baselines/reference/staticMemberAccessOffDerivedType1.js
@@ -13,8 +13,7 @@ class P extends SomeBase {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var SomeBase = (function () {
     function SomeBase() {
diff --git a/tests/baselines/reference/staticPropSuper.js b/tests/baselines/reference/staticPropSuper.js
index f0d50b3ecb6..3f75dc8e26b 100644
--- a/tests/baselines/reference/staticPropSuper.js
+++ b/tests/baselines/reference/staticPropSuper.js
@@ -39,8 +39,7 @@ class E extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/strictModeInConstructor.js b/tests/baselines/reference/strictModeInConstructor.js
index fef1ef46b1a..7fd74aa108f 100644
--- a/tests/baselines/reference/strictModeInConstructor.js
+++ b/tests/baselines/reference/strictModeInConstructor.js
@@ -64,8 +64,7 @@ class Ds extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/strictModeReservedWordInClassDeclaration.js b/tests/baselines/reference/strictModeReservedWordInClassDeclaration.js
index 9ee817182c2..e4bef791374 100644
--- a/tests/baselines/reference/strictModeReservedWordInClassDeclaration.js
+++ b/tests/baselines/reference/strictModeReservedWordInClassDeclaration.js
@@ -32,8 +32,7 @@ class H extends package.A { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo(private, public, static) {
diff --git a/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations2.js b/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations2.js
index b6bd2dbd437..97e3e9b0f5b 100644
--- a/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations2.js
+++ b/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations2.js
@@ -44,8 +44,7 @@ var b: { [x: string]: A } = {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/subtypesOfTypeParameter.js b/tests/baselines/reference/subtypesOfTypeParameter.js
index 5abdd633424..c7b14a4129c 100644
--- a/tests/baselines/reference/subtypesOfTypeParameter.js
+++ b/tests/baselines/reference/subtypesOfTypeParameter.js
@@ -110,8 +110,7 @@ function f2<T, U>(x: T, y: U) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C3 = (function () {
     function C3() {
diff --git a/tests/baselines/reference/subtypesOfTypeParameterWithConstraints.js b/tests/baselines/reference/subtypesOfTypeParameterWithConstraints.js
index afe9b998bd4..194c1835147 100644
--- a/tests/baselines/reference/subtypesOfTypeParameterWithConstraints.js
+++ b/tests/baselines/reference/subtypesOfTypeParameterWithConstraints.js
@@ -172,8 +172,7 @@ class D29<T extends U, U extends V, V extends Date> extends C3<V> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C3 = (function () {
     function C3() {
diff --git a/tests/baselines/reference/subtypesOfTypeParameterWithConstraints4.js b/tests/baselines/reference/subtypesOfTypeParameterWithConstraints4.js
index 6f1756912a6..370bbf2b8ff 100644
--- a/tests/baselines/reference/subtypesOfTypeParameterWithConstraints4.js
+++ b/tests/baselines/reference/subtypesOfTypeParameterWithConstraints4.js
@@ -83,8 +83,7 @@ class D9<T extends Foo, U extends Foo, V> extends B1<U> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/subtypesOfTypeParameterWithRecursiveConstraints.js b/tests/baselines/reference/subtypesOfTypeParameterWithRecursiveConstraints.js
index 3d2b6372302..c5d4e68b516 100644
--- a/tests/baselines/reference/subtypesOfTypeParameterWithRecursiveConstraints.js
+++ b/tests/baselines/reference/subtypesOfTypeParameterWithRecursiveConstraints.js
@@ -162,8 +162,7 @@ module M2 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Foo = (function () {
     function Foo() {
diff --git a/tests/baselines/reference/subtypingTransitivity.js b/tests/baselines/reference/subtypingTransitivity.js
index 9dcb4095aa2..9bc5cd93209 100644
--- a/tests/baselines/reference/subtypingTransitivity.js
+++ b/tests/baselines/reference/subtypingTransitivity.js
@@ -23,8 +23,7 @@ b.x = 1; // assigned number to string
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var B = (function () {
     function B() {
diff --git a/tests/baselines/reference/subtypingWithCallSignatures2.js b/tests/baselines/reference/subtypingWithCallSignatures2.js
index db6f1d85954..f11b83c4da6 100644
--- a/tests/baselines/reference/subtypingWithCallSignatures2.js
+++ b/tests/baselines/reference/subtypingWithCallSignatures2.js
@@ -177,8 +177,7 @@ var r18 = foo18(r18arg1);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/subtypingWithCallSignatures3.js b/tests/baselines/reference/subtypingWithCallSignatures3.js
index d7ff8a79b6c..2b45b75b95f 100644
--- a/tests/baselines/reference/subtypingWithCallSignatures3.js
+++ b/tests/baselines/reference/subtypingWithCallSignatures3.js
@@ -124,8 +124,7 @@ module WithGenericSignaturesInBaseType {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Errors;
 (function (Errors) {
diff --git a/tests/baselines/reference/subtypingWithCallSignatures4.js b/tests/baselines/reference/subtypingWithCallSignatures4.js
index 739e3cacd86..d1d30437cd6 100644
--- a/tests/baselines/reference/subtypingWithCallSignatures4.js
+++ b/tests/baselines/reference/subtypingWithCallSignatures4.js
@@ -116,8 +116,7 @@ var r18 = foo18(r18arg);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/subtypingWithConstructSignatures2.js b/tests/baselines/reference/subtypingWithConstructSignatures2.js
index 4e93ddbbe55..df050ffd6e9 100644
--- a/tests/baselines/reference/subtypingWithConstructSignatures2.js
+++ b/tests/baselines/reference/subtypingWithConstructSignatures2.js
@@ -177,8 +177,7 @@ var r18 = foo18(r18arg1);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/subtypingWithConstructSignatures3.js b/tests/baselines/reference/subtypingWithConstructSignatures3.js
index 7022b4b395c..ccc6fb872c5 100644
--- a/tests/baselines/reference/subtypingWithConstructSignatures3.js
+++ b/tests/baselines/reference/subtypingWithConstructSignatures3.js
@@ -126,8 +126,7 @@ module WithGenericSignaturesInBaseType {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Errors;
 (function (Errors) {
diff --git a/tests/baselines/reference/subtypingWithConstructSignatures4.js b/tests/baselines/reference/subtypingWithConstructSignatures4.js
index a16ea8e2397..67b83aa94c9 100644
--- a/tests/baselines/reference/subtypingWithConstructSignatures4.js
+++ b/tests/baselines/reference/subtypingWithConstructSignatures4.js
@@ -116,8 +116,7 @@ var r18 = foo18(r18arg);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/subtypingWithConstructSignatures5.js b/tests/baselines/reference/subtypingWithConstructSignatures5.js
index fe3b86d1775..ec3bad2c1f3 100644
--- a/tests/baselines/reference/subtypingWithConstructSignatures5.js
+++ b/tests/baselines/reference/subtypingWithConstructSignatures5.js
@@ -54,8 +54,7 @@ interface I extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/subtypingWithConstructSignatures6.js b/tests/baselines/reference/subtypingWithConstructSignatures6.js
index 990b654bf45..1c7a2d883c3 100644
--- a/tests/baselines/reference/subtypingWithConstructSignatures6.js
+++ b/tests/baselines/reference/subtypingWithConstructSignatures6.js
@@ -57,8 +57,7 @@ interface I9<T> extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/subtypingWithNumericIndexer.js b/tests/baselines/reference/subtypingWithNumericIndexer.js
index a7790fba564..2ad6a2ebedc 100644
--- a/tests/baselines/reference/subtypingWithNumericIndexer.js
+++ b/tests/baselines/reference/subtypingWithNumericIndexer.js
@@ -44,8 +44,7 @@ module Generics {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/subtypingWithNumericIndexer3.js b/tests/baselines/reference/subtypingWithNumericIndexer3.js
index c3fff86274f..f4c2d1d9da9 100644
--- a/tests/baselines/reference/subtypingWithNumericIndexer3.js
+++ b/tests/baselines/reference/subtypingWithNumericIndexer3.js
@@ -48,8 +48,7 @@ module Generics {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/subtypingWithNumericIndexer4.js b/tests/baselines/reference/subtypingWithNumericIndexer4.js
index e7ec08436a7..7956464d172 100644
--- a/tests/baselines/reference/subtypingWithNumericIndexer4.js
+++ b/tests/baselines/reference/subtypingWithNumericIndexer4.js
@@ -32,8 +32,7 @@ module Generics {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/subtypingWithObjectMembers.js b/tests/baselines/reference/subtypingWithObjectMembers.js
index 28af7239222..fc452ba8cf4 100644
--- a/tests/baselines/reference/subtypingWithObjectMembers.js
+++ b/tests/baselines/reference/subtypingWithObjectMembers.js
@@ -71,8 +71,7 @@ module TwoLevels {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/subtypingWithObjectMembers4.js b/tests/baselines/reference/subtypingWithObjectMembers4.js
index b04c3056a3e..487a5969f71 100644
--- a/tests/baselines/reference/subtypingWithObjectMembers4.js
+++ b/tests/baselines/reference/subtypingWithObjectMembers4.js
@@ -38,8 +38,7 @@ class B3 extends A3 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/subtypingWithObjectMembersAccessibility.js b/tests/baselines/reference/subtypingWithObjectMembersAccessibility.js
index d3b62890855..f08f2367d2c 100644
--- a/tests/baselines/reference/subtypingWithObjectMembersAccessibility.js
+++ b/tests/baselines/reference/subtypingWithObjectMembersAccessibility.js
@@ -38,8 +38,7 @@ class B3 extends A3 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/subtypingWithObjectMembersAccessibility2.js b/tests/baselines/reference/subtypingWithObjectMembersAccessibility2.js
index 4a0ff448b7b..c23405cd50c 100644
--- a/tests/baselines/reference/subtypingWithObjectMembersAccessibility2.js
+++ b/tests/baselines/reference/subtypingWithObjectMembersAccessibility2.js
@@ -66,8 +66,7 @@ module ImplicitPublic {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/subtypingWithStringIndexer.js b/tests/baselines/reference/subtypingWithStringIndexer.js
index 4b398451de8..5f606520a65 100644
--- a/tests/baselines/reference/subtypingWithStringIndexer.js
+++ b/tests/baselines/reference/subtypingWithStringIndexer.js
@@ -45,8 +45,7 @@ module Generics {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/subtypingWithStringIndexer3.js b/tests/baselines/reference/subtypingWithStringIndexer3.js
index cf1ec80a8d2..6ce66c4e723 100644
--- a/tests/baselines/reference/subtypingWithStringIndexer3.js
+++ b/tests/baselines/reference/subtypingWithStringIndexer3.js
@@ -48,8 +48,7 @@ module Generics {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/subtypingWithStringIndexer4.js b/tests/baselines/reference/subtypingWithStringIndexer4.js
index e6aa298fed8..19d36e475c2 100644
--- a/tests/baselines/reference/subtypingWithStringIndexer4.js
+++ b/tests/baselines/reference/subtypingWithStringIndexer4.js
@@ -32,8 +32,7 @@ module Generics {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/super.js b/tests/baselines/reference/super.js
index ed220ae1f18..a6b698413ec 100644
--- a/tests/baselines/reference/super.js
+++ b/tests/baselines/reference/super.js
@@ -41,8 +41,7 @@ s.foo() + ss.foo();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/super1.js b/tests/baselines/reference/super1.js
index 1bf75783a60..6a52cfcd9e7 100644
--- a/tests/baselines/reference/super1.js
+++ b/tests/baselines/reference/super1.js
@@ -70,8 +70,7 @@ module Base4 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // Case 1
 var Base1 = (function () {
diff --git a/tests/baselines/reference/super2.js b/tests/baselines/reference/super2.js
index 0f5531a8d57..9d865194a2a 100644
--- a/tests/baselines/reference/super2.js
+++ b/tests/baselines/reference/super2.js
@@ -54,8 +54,7 @@ results1.x() + results1.y() + results2.y();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // Case 5
 var Base5 = (function () {
diff --git a/tests/baselines/reference/superAccess.js b/tests/baselines/reference/superAccess.js
index bf6a9ee3ad0..bb5a71a0b8f 100644
--- a/tests/baselines/reference/superAccess.js
+++ b/tests/baselines/reference/superAccess.js
@@ -17,8 +17,7 @@ class MyDerived extends MyBase {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var MyBase = (function () {
     function MyBase() {
diff --git a/tests/baselines/reference/superAccess2.js b/tests/baselines/reference/superAccess2.js
index afcba34aa5d..fd20f424ba3 100644
--- a/tests/baselines/reference/superAccess2.js
+++ b/tests/baselines/reference/superAccess2.js
@@ -28,8 +28,7 @@ class Q extends P {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var P = (function () {
     function P() {
diff --git a/tests/baselines/reference/superAccessInFatArrow1.js b/tests/baselines/reference/superAccessInFatArrow1.js
index 6222bf42fee..0dc69179c92 100644
--- a/tests/baselines/reference/superAccessInFatArrow1.js
+++ b/tests/baselines/reference/superAccessInFatArrow1.js
@@ -19,8 +19,7 @@ module test {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var test;
 (function (test) {
diff --git a/tests/baselines/reference/superCallArgsMustMatch.js b/tests/baselines/reference/superCallArgsMustMatch.js
index 7c7948cc387..3369cf7e8df 100644
--- a/tests/baselines/reference/superCallArgsMustMatch.js
+++ b/tests/baselines/reference/superCallArgsMustMatch.js
@@ -29,8 +29,7 @@ class T6 extends T5<number>{
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var T5 = (function () {
     function T5(bar) {
diff --git a/tests/baselines/reference/superCallAssignResult.js b/tests/baselines/reference/superCallAssignResult.js
index a83e5b3de75..24a198e3420 100644
--- a/tests/baselines/reference/superCallAssignResult.js
+++ b/tests/baselines/reference/superCallAssignResult.js
@@ -14,8 +14,7 @@ class H extends E {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var E = (function () {
     function E(arg) {
diff --git a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericType1.js b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericType1.js
index 15e26b5481f..d59f6f5a578 100644
--- a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericType1.js
+++ b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericType1.js
@@ -15,8 +15,7 @@ class D extends B<any> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var D = (function (_super) {
     __extends(D, _super);
diff --git a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericType2.js b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericType2.js
index 15d24015a04..a3d5d42c822 100644
--- a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericType2.js
+++ b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericType2.js
@@ -14,8 +14,7 @@ class D extends B<any> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var D = (function (_super) {
     __extends(D, _super);
diff --git a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.errors.txt b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.errors.txt
index 14905b224ad..f491cac9f0c 100644
--- a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.errors.txt
+++ b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.errors.txt
@@ -1,8 +1,7 @@
 tests/cases/compiler/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.ts(8,17): error TS2314: Generic type 'A<T1, T2>' requires 2 type argument(s).
-tests/cases/compiler/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.ts(9,21): error TS2335: 'super' can only be referenced in a derived class.
 
 
-==== tests/cases/compiler/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.ts (2 errors) ====
+==== tests/cases/compiler/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.ts (1 errors) ====
     
     class A<T1, T2> {
         constructor(private map: (value: T1) => T2) {
@@ -14,6 +13,4 @@ tests/cases/compiler/superCallFromClassThatDerivesFromGenericTypeButWithIncorrec
                     ~~~~~~~~~
 !!! error TS2314: Generic type 'A<T1, T2>' requires 2 type argument(s).
         constructor() { super(value => String(value)); }
-                        ~~~~~
-!!! error TS2335: 'super' can only be referenced in a derived class.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.js b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.js
index 114505b85a2..155258861bf 100644
--- a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.js
+++ b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithIncorrectNumberOfTypeArguments1.js
@@ -14,8 +14,7 @@ class B extends A<number> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A(map) {
diff --git a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.errors.txt b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.errors.txt
index d402272df1b..32047f3b417 100644
--- a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.errors.txt
+++ b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.errors.txt
@@ -1,8 +1,7 @@
 tests/cases/compiler/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.ts(8,17): error TS2314: Generic type 'A<T1, T2>' requires 2 type argument(s).
-tests/cases/compiler/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.ts(9,21): error TS2335: 'super' can only be referenced in a derived class.
 
 
-==== tests/cases/compiler/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.ts (2 errors) ====
+==== tests/cases/compiler/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.ts (1 errors) ====
     
     class A<T1, T2> {
         constructor(private map: (value: T1) => T2) {
@@ -14,6 +13,4 @@ tests/cases/compiler/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeAr
                     ~
 !!! error TS2314: Generic type 'A<T1, T2>' requires 2 type argument(s).
         constructor() { super(value => String(value)); }
-                        ~~~~~
-!!! error TS2335: 'super' can only be referenced in a derived class.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.js b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.js
index 226665e3e67..37883b9921a 100644
--- a/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.js
+++ b/tests/baselines/reference/superCallFromClassThatDerivesFromGenericTypeButWithNoTypeArguments1.js
@@ -14,8 +14,7 @@ class B extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A(map) {
diff --git a/tests/baselines/reference/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.errors.txt b/tests/baselines/reference/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.errors.txt
index 8bbf8b87cd3..4aa9e5a134b 100644
--- a/tests/baselines/reference/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.errors.txt
+++ b/tests/baselines/reference/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.errors.txt
@@ -1,8 +1,7 @@
 tests/cases/compiler/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.ts(8,17): error TS2315: Type 'A' is not generic.
-tests/cases/compiler/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.ts(9,21): error TS2335: 'super' can only be referenced in a derived class.
 
 
-==== tests/cases/compiler/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.ts (2 errors) ====
+==== tests/cases/compiler/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.ts (1 errors) ====
     
     class A {
         constructor(private map: (value: number) => string) {
@@ -14,6 +13,4 @@ tests/cases/compiler/superCallFromClassThatDerivesNonGenericTypeButWithTypeArgum
                     ~~~~~~~~~~~~~~~~~
 !!! error TS2315: Type 'A' is not generic.
         constructor() { super(value => String(value)); }
-                        ~~~~~
-!!! error TS2335: 'super' can only be referenced in a derived class.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.js b/tests/baselines/reference/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.js
index 7c07e78b0f9..dbd4528c39f 100644
--- a/tests/baselines/reference/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.js
+++ b/tests/baselines/reference/superCallFromClassThatDerivesNonGenericTypeButWithTypeArguments1.js
@@ -14,8 +14,7 @@ class B extends A<number, string> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A(map) {
diff --git a/tests/baselines/reference/superCallInNonStaticMethod.js b/tests/baselines/reference/superCallInNonStaticMethod.js
index c3038e23c4c..7de6a100451 100644
--- a/tests/baselines/reference/superCallInNonStaticMethod.js
+++ b/tests/baselines/reference/superCallInNonStaticMethod.js
@@ -54,8 +54,7 @@ class Other extends Doing {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Doing = (function () {
     function Doing() {
diff --git a/tests/baselines/reference/superCallInStaticMethod.js b/tests/baselines/reference/superCallInStaticMethod.js
index 7e57cd2d2e8..9978773739f 100644
--- a/tests/baselines/reference/superCallInStaticMethod.js
+++ b/tests/baselines/reference/superCallInStaticMethod.js
@@ -50,8 +50,7 @@ class Other extends Doing {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Doing = (function () {
     function Doing() {
diff --git a/tests/baselines/reference/superCallOutsideConstructor.js b/tests/baselines/reference/superCallOutsideConstructor.js
index 0a1822bc549..c2152e13db0 100644
--- a/tests/baselines/reference/superCallOutsideConstructor.js
+++ b/tests/baselines/reference/superCallOutsideConstructor.js
@@ -26,8 +26,7 @@ var d = new D();
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/superCallParameterContextualTyping1.js b/tests/baselines/reference/superCallParameterContextualTyping1.js
index 4888473319e..b7508e4cd7d 100644
--- a/tests/baselines/reference/superCallParameterContextualTyping1.js
+++ b/tests/baselines/reference/superCallParameterContextualTyping1.js
@@ -16,8 +16,7 @@ class B extends A<number, string> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A(map) {
diff --git a/tests/baselines/reference/superCallParameterContextualTyping2.js b/tests/baselines/reference/superCallParameterContextualTyping2.js
index ab6093c42be..996e0374c7f 100644
--- a/tests/baselines/reference/superCallParameterContextualTyping2.js
+++ b/tests/baselines/reference/superCallParameterContextualTyping2.js
@@ -15,8 +15,7 @@ class C extends A<number, string> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A(map) {
diff --git a/tests/baselines/reference/superCallParameterContextualTyping3.js b/tests/baselines/reference/superCallParameterContextualTyping3.js
index 574d281ed09..6f1311e58ab 100644
--- a/tests/baselines/reference/superCallParameterContextualTyping3.js
+++ b/tests/baselines/reference/superCallParameterContextualTyping3.js
@@ -35,8 +35,7 @@ class C extends CBase<string> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var CBase = (function () {
     function CBase(param) {
diff --git a/tests/baselines/reference/superCalls.js b/tests/baselines/reference/superCalls.js
index d2e4f9ff7f1..bd54ba34b56 100644
--- a/tests/baselines/reference/superCalls.js
+++ b/tests/baselines/reference/superCalls.js
@@ -34,8 +34,7 @@ class OtherDerived extends OtherBase {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(n) {
diff --git a/tests/baselines/reference/superCallsInConstructor.js b/tests/baselines/reference/superCallsInConstructor.js
index 6bd313898d4..c238808b959 100644
--- a/tests/baselines/reference/superCallsInConstructor.js
+++ b/tests/baselines/reference/superCallsInConstructor.js
@@ -24,8 +24,7 @@ class Derived extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/superErrors.js b/tests/baselines/reference/superErrors.js
index 2e1cd346cd4..3a3de509120 100644
--- a/tests/baselines/reference/superErrors.js
+++ b/tests/baselines/reference/superErrors.js
@@ -55,8 +55,7 @@ class RegisteredUser extends User {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function foo() {
     // super in a non class context
diff --git a/tests/baselines/reference/superInCatchBlock1.js b/tests/baselines/reference/superInCatchBlock1.js
index 38131f5f08e..cf4c69c7b61 100644
--- a/tests/baselines/reference/superInCatchBlock1.js
+++ b/tests/baselines/reference/superInCatchBlock1.js
@@ -17,8 +17,7 @@ class B extends A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/superInConstructorParam1.js b/tests/baselines/reference/superInConstructorParam1.js
index aaf4162e992..7c0cc7bf40d 100644
--- a/tests/baselines/reference/superInConstructorParam1.js
+++ b/tests/baselines/reference/superInConstructorParam1.js
@@ -14,8 +14,7 @@ class C extends B {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var B = (function () {
     function B() {
diff --git a/tests/baselines/reference/superInLambdas.js b/tests/baselines/reference/superInLambdas.js
index 5640425f6bc..89d5798f882 100644
--- a/tests/baselines/reference/superInLambdas.js
+++ b/tests/baselines/reference/superInLambdas.js
@@ -71,8 +71,7 @@ class RegisteredUser4 extends User {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var User = (function () {
     function User() {
diff --git a/tests/baselines/reference/superNewCall1.js b/tests/baselines/reference/superNewCall1.js
index 1b11b61ce2f..aa25e65e14d 100644
--- a/tests/baselines/reference/superNewCall1.js
+++ b/tests/baselines/reference/superNewCall1.js
@@ -16,8 +16,7 @@ class B extends A<number, string> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A(map) {
diff --git a/tests/baselines/reference/superPropertyAccess.js b/tests/baselines/reference/superPropertyAccess.js
index 016fc09ff96..95dbb2f94e0 100644
--- a/tests/baselines/reference/superPropertyAccess.js
+++ b/tests/baselines/reference/superPropertyAccess.js
@@ -40,8 +40,7 @@ class MyDerived extends MyBase {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var MyBase = (function () {
     function MyBase() {
diff --git a/tests/baselines/reference/superPropertyAccess1.js b/tests/baselines/reference/superPropertyAccess1.js
index 1ee834f3495..748331af95f 100644
--- a/tests/baselines/reference/superPropertyAccess1.js
+++ b/tests/baselines/reference/superPropertyAccess1.js
@@ -31,8 +31,7 @@ class D extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/superPropertyAccess2.js b/tests/baselines/reference/superPropertyAccess2.js
index 0877cf23b9d..dccd4717ee0 100644
--- a/tests/baselines/reference/superPropertyAccess2.js
+++ b/tests/baselines/reference/superPropertyAccess2.js
@@ -31,8 +31,7 @@ class D extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/superPropertyAccessNoError.js b/tests/baselines/reference/superPropertyAccessNoError.js
index f8ee7f6d01b..44a6910a386 100644
--- a/tests/baselines/reference/superPropertyAccessNoError.js
+++ b/tests/baselines/reference/superPropertyAccessNoError.js
@@ -70,8 +70,7 @@ class SomeDerivedClass extends SomeBaseClass {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var SomeBaseClass = (function () {
     function SomeBaseClass() {
diff --git a/tests/baselines/reference/superWithGenericSpecialization.js b/tests/baselines/reference/superWithGenericSpecialization.js
index 5cd85f90735..3d1ea0f77a9 100644
--- a/tests/baselines/reference/superWithGenericSpecialization.js
+++ b/tests/baselines/reference/superWithGenericSpecialization.js
@@ -18,8 +18,7 @@ var r2: number = d.y;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/superWithGenerics.js b/tests/baselines/reference/superWithGenerics.js
index 8ba6f878dc2..482c7ba0694 100644
--- a/tests/baselines/reference/superWithGenerics.js
+++ b/tests/baselines/reference/superWithGenerics.js
@@ -15,8 +15,7 @@ class D extends B<any> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var D = (function (_super) {
     __extends(D, _super);
diff --git a/tests/baselines/reference/superWithTypeArgument.js b/tests/baselines/reference/superWithTypeArgument.js
index 2e5ea93a47a..6d5690cd689 100644
--- a/tests/baselines/reference/superWithTypeArgument.js
+++ b/tests/baselines/reference/superWithTypeArgument.js
@@ -13,8 +13,7 @@ class D<T> extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/superWithTypeArgument2.js b/tests/baselines/reference/superWithTypeArgument2.js
index c33497d58fd..588094cd864 100644
--- a/tests/baselines/reference/superWithTypeArgument2.js
+++ b/tests/baselines/reference/superWithTypeArgument2.js
@@ -13,8 +13,7 @@ class D<T> extends C<T> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/superWithTypeArgument3.js b/tests/baselines/reference/superWithTypeArgument3.js
index 1266d97f264..8f0ba6c0861 100644
--- a/tests/baselines/reference/superWithTypeArgument3.js
+++ b/tests/baselines/reference/superWithTypeArgument3.js
@@ -17,8 +17,7 @@ class D<T> extends C<T> {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/super_inside-object-literal-getters-and-setters.js b/tests/baselines/reference/super_inside-object-literal-getters-and-setters.js
index 97fa57528cf..d2f240b766d 100644
--- a/tests/baselines/reference/super_inside-object-literal-getters-and-setters.js
+++ b/tests/baselines/reference/super_inside-object-literal-getters-and-setters.js
@@ -31,8 +31,7 @@ class SuperObjectTest extends F {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var ObjectLiteral;
 (function (ObjectLiteral) {
diff --git a/tests/baselines/reference/switchStatements.js b/tests/baselines/reference/switchStatements.js
index debd9a4d531..39a4b2c901d 100644
--- a/tests/baselines/reference/switchStatements.js
+++ b/tests/baselines/reference/switchStatements.js
@@ -59,8 +59,7 @@ switch ((<T>(x: T) => '')(1)) { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/systemModule13.js b/tests/baselines/reference/systemModule13.js
new file mode 100644
index 00000000000..c66e123c738
--- /dev/null
+++ b/tests/baselines/reference/systemModule13.js
@@ -0,0 +1,21 @@
+//// [systemModule13.ts]
+
+export let [x,y,z] = [1, 2, 3];
+export const {a: z0, b: {c: z1}} = {a: true, b: {c: "123"}};
+for ([x] of [[1]]) {}
+
+//// [systemModule13.js]
+System.register([], function(exports_1) {
+    var x, y, z, z0, z1;
+    return {
+        setters:[],
+        execute: function() {
+            _a = [1, 2, 3], exports_1("x", x = _a[0]), exports_1("y", y = _a[1]), exports_1("z", z = _a[2]);
+            _b = { a: true, b: { c: "123" } }, exports_1("z0", z0 = _b.a), exports_1("z1", z1 = _b.b.c);
+            for (var _i = 0, _c = [[1]]; _i < _c.length; _i++) {
+                exports_1("x", x = _c[_i][0]);
+            }
+        }
+    }
+    var _a, _b;
+});
diff --git a/tests/baselines/reference/systemModule13.symbols b/tests/baselines/reference/systemModule13.symbols
new file mode 100644
index 00000000000..d9e64335c2b
--- /dev/null
+++ b/tests/baselines/reference/systemModule13.symbols
@@ -0,0 +1,17 @@
+=== tests/cases/compiler/systemModule13.ts ===
+
+export let [x,y,z] = [1, 2, 3];
+>x : Symbol(x, Decl(systemModule13.ts, 1, 12))
+>y : Symbol(y, Decl(systemModule13.ts, 1, 14))
+>z : Symbol(z, Decl(systemModule13.ts, 1, 16))
+
+export const {a: z0, b: {c: z1}} = {a: true, b: {c: "123"}};
+>z0 : Symbol(z0, Decl(systemModule13.ts, 2, 14))
+>z1 : Symbol(z1, Decl(systemModule13.ts, 2, 25))
+>a : Symbol(a, Decl(systemModule13.ts, 2, 36))
+>b : Symbol(b, Decl(systemModule13.ts, 2, 44))
+>c : Symbol(c, Decl(systemModule13.ts, 2, 49))
+
+for ([x] of [[1]]) {}
+>x : Symbol(x, Decl(systemModule13.ts, 1, 12))
+
diff --git a/tests/baselines/reference/systemModule13.types b/tests/baselines/reference/systemModule13.types
new file mode 100644
index 00000000000..35f22be98b8
--- /dev/null
+++ b/tests/baselines/reference/systemModule13.types
@@ -0,0 +1,32 @@
+=== tests/cases/compiler/systemModule13.ts ===
+
+export let [x,y,z] = [1, 2, 3];
+>x : number
+>y : number
+>z : number
+>[1, 2, 3] : [number, number, number]
+>1 : number
+>2 : number
+>3 : number
+
+export const {a: z0, b: {c: z1}} = {a: true, b: {c: "123"}};
+>a : any
+>z0 : boolean
+>b : any
+>c : any
+>z1 : string
+>{a: true, b: {c: "123"}} : { a: boolean; b: { c: string; }; }
+>a : boolean
+>true : boolean
+>b : { c: string; }
+>{c: "123"} : { c: string; }
+>c : string
+>"123" : string
+
+for ([x] of [[1]]) {}
+>[x] : number[]
+>x : number
+>[[1]] : number[][]
+>[1] : number[]
+>1 : number
+
diff --git a/tests/baselines/reference/targetTypeBaseCalls.js b/tests/baselines/reference/targetTypeBaseCalls.js
index bde689ba2c9..41673a62efd 100644
--- a/tests/baselines/reference/targetTypeBaseCalls.js
+++ b/tests/baselines/reference/targetTypeBaseCalls.js
@@ -22,8 +22,7 @@ class Bar extends Foo { constructor() { super(function(s) { s = 5 }) } }  // err
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function foo(x) { }
 var Foo = (function () {
diff --git a/tests/baselines/reference/thisInInvalidContexts.errors.txt b/tests/baselines/reference/thisInInvalidContexts.errors.txt
index 9cb554ab5df..d6f24cbcfdc 100644
--- a/tests/baselines/reference/thisInInvalidContexts.errors.txt
+++ b/tests/baselines/reference/thisInInvalidContexts.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(3,16): error TS2334: 'this' cannot be referenced in a static property initializer.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(22,15): error TS2332: 'this' cannot be referenced in current location.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(28,13): error TS2331: 'this' cannot be referenced in a module or namespace body.
-tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(38,25): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(38,25): error TS2507: Type 'any' is not a constructor function type.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(44,9): error TS2332: 'this' cannot be referenced in current location.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(45,9): error TS2332: 'this' cannot be referenced in current location.
 
@@ -52,7 +52,7 @@ tests/cases/conformance/expressions/thisKeyword/thisInInvalidContexts.ts(45,9):
     
     class ErrClass3 extends this {
                             ~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'any' is not a constructor function type.
     
     }
     
diff --git a/tests/baselines/reference/thisInInvalidContexts.js b/tests/baselines/reference/thisInInvalidContexts.js
index afce4ec0375..84b96404683 100644
--- a/tests/baselines/reference/thisInInvalidContexts.js
+++ b/tests/baselines/reference/thisInInvalidContexts.js
@@ -52,8 +52,7 @@ enum SomeEnum {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 //'this' in static member initializer
 var ErrClass1 = (function () {
diff --git a/tests/baselines/reference/thisInInvalidContextsExternalModule.errors.txt b/tests/baselines/reference/thisInInvalidContextsExternalModule.errors.txt
index 96fab807f5e..df47901d771 100644
--- a/tests/baselines/reference/thisInInvalidContextsExternalModule.errors.txt
+++ b/tests/baselines/reference/thisInInvalidContextsExternalModule.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(3,16): error TS2334: 'this' cannot be referenced in a static property initializer.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(22,15): error TS2332: 'this' cannot be referenced in current location.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(28,13): error TS2331: 'this' cannot be referenced in a module or namespace body.
-tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(38,25): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(38,25): error TS2507: Type 'any' is not a constructor function type.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(44,9): error TS2332: 'this' cannot be referenced in current location.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(45,9): error TS2332: 'this' cannot be referenced in current location.
 tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalModule.ts(48,1): error TS1148: Cannot compile modules unless the '--module' flag is provided.
@@ -53,7 +53,7 @@ tests/cases/conformance/expressions/thisKeyword/thisInInvalidContextsExternalMod
     
     class ErrClass3 extends this {
                             ~~~~
-!!! error TS2507: Base expression is not of a constructor function type.
+!!! error TS2507: Type 'any' is not a constructor function type.
     
     }
     
diff --git a/tests/baselines/reference/thisInInvalidContextsExternalModule.js b/tests/baselines/reference/thisInInvalidContextsExternalModule.js
index 8fcbe226437..7de94be9420 100644
--- a/tests/baselines/reference/thisInInvalidContextsExternalModule.js
+++ b/tests/baselines/reference/thisInInvalidContextsExternalModule.js
@@ -52,8 +52,7 @@ export = this; // Should be an error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 //'this' in static member initializer
 var ErrClass1 = (function () {
diff --git a/tests/baselines/reference/thisInSuperCall.js b/tests/baselines/reference/thisInSuperCall.js
index 3da6d9c8a68..f7d7ca4e4fd 100644
--- a/tests/baselines/reference/thisInSuperCall.js
+++ b/tests/baselines/reference/thisInSuperCall.js
@@ -26,8 +26,7 @@ class Foo3 extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(x) {
diff --git a/tests/baselines/reference/thisInSuperCall1.js b/tests/baselines/reference/thisInSuperCall1.js
index b0ff1bd4bab..4ae43784fe0 100644
--- a/tests/baselines/reference/thisInSuperCall1.js
+++ b/tests/baselines/reference/thisInSuperCall1.js
@@ -14,8 +14,7 @@ class Foo extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(a) {
diff --git a/tests/baselines/reference/thisInSuperCall2.js b/tests/baselines/reference/thisInSuperCall2.js
index fca671a2c73..a9bbeda9fe7 100644
--- a/tests/baselines/reference/thisInSuperCall2.js
+++ b/tests/baselines/reference/thisInSuperCall2.js
@@ -23,8 +23,7 @@ class Foo2 extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(a) {
diff --git a/tests/baselines/reference/thisInSuperCall3.js b/tests/baselines/reference/thisInSuperCall3.js
index fe2bdec77ed..ba27add2d97 100644
--- a/tests/baselines/reference/thisInSuperCall3.js
+++ b/tests/baselines/reference/thisInSuperCall3.js
@@ -16,8 +16,7 @@ class Foo extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(a) {
diff --git a/tests/baselines/reference/typeAssertions.js b/tests/baselines/reference/typeAssertions.js
index 51ca6a27f0e..3645e61f2ba 100644
--- a/tests/baselines/reference/typeAssertions.js
+++ b/tests/baselines/reference/typeAssertions.js
@@ -46,8 +46,7 @@ someOther = <SomeOther>someOther;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // Function call whose argument is a 1 arg generic function call with explicit type arguments
 function fn1(t) { }
diff --git a/tests/baselines/reference/typeGuardFunction.js b/tests/baselines/reference/typeGuardFunction.js
index f6b752c8c04..bff304682af 100644
--- a/tests/baselines/reference/typeGuardFunction.js
+++ b/tests/baselines/reference/typeGuardFunction.js
@@ -87,8 +87,7 @@ let union3: boolean | B = isA(union2) || union2;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/typeGuardFunctionErrors.errors.txt b/tests/baselines/reference/typeGuardFunctionErrors.errors.txt
index 1542bbe0fee..499a51035f2 100644
--- a/tests/baselines/reference/typeGuardFunctionErrors.errors.txt
+++ b/tests/baselines/reference/typeGuardFunctionErrors.errors.txt
@@ -1,42 +1,43 @@
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(15,12): error TS2322: Type 'string' is not assignable to type 'boolean'.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(22,33): error TS2304: Cannot find name 'x'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(26,10): error TS2391: Function implementation is missing or not immediately following the declaration.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(27,5): error TS1131: Property or signature expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(28,1): error TS1128: Declaration or statement expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(30,38): error TS1225: Cannot find parameter 'x'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(34,51): error TS2322: Type 'B' is not assignable to type 'A'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(26,33): error TS1225: Cannot find parameter 'x'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(30,10): error TS2391: Function implementation is missing or not immediately following the declaration.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(31,5): error TS1131: Property or signature expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(32,1): error TS1128: Declaration or statement expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(34,38): error TS1225: Cannot find parameter 'x'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(38,51): error TS2322: Type 'B' is not assignable to type 'A'.
   Property 'propA' is missing in type 'B'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(38,56): error TS2322: Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(42,56): error TS2322: Type 'T[]' is not assignable to type 'string'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(56,7): error TS2339: Property 'propB' does not exist on type 'A'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(61,7): error TS2339: Property 'propB' does not exist on type 'A'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(66,7): error TS2339: Property 'propB' does not exist on type 'A'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(71,46): error TS2345: Argument of type '(p1: any) => boolean' is not assignable to parameter of type '(p1: any) => boolean'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(42,56): error TS2322: Type 'number' is not assignable to type 'string'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(46,56): error TS2322: Type 'T[]' is not assignable to type 'string'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(60,7): error TS2339: Property 'propB' does not exist on type 'A'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(65,7): error TS2339: Property 'propB' does not exist on type 'A'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(70,7): error TS2339: Property 'propB' does not exist on type 'A'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(75,46): error TS2345: Argument of type '(p1: any) => boolean' is not assignable to parameter of type '(p1: any) => boolean'.
   Type predicate 'p1 is C' is not assignable to 'p1 is B'.
     Type 'C' is not assignable to type 'B'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(75,1): error TS2322: Type '(p1: any, p2: any) => boolean' is not assignable to type '(p1: any, p2: any) => boolean'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(79,1): error TS2322: Type '(p1: any, p2: any) => boolean' is not assignable to type '(p1: any, p2: any) => boolean'.
   Signature '(p1: any, p2: any): boolean' must have a type predicate.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(81,1): error TS2322: Type '(p1: any, p2: any) => boolean' is not assignable to type '(p1: any, p2: any) => boolean'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(85,1): error TS2322: Type '(p1: any, p2: any) => boolean' is not assignable to type '(p1: any, p2: any) => boolean'.
   Type predicate 'p2 is A' is not assignable to 'p1 is A'.
     Parameter 'p2' is not in the same position as parameter 'p1'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(87,1): error TS2322: Type '(p1: any, p2: any, p3: any) => boolean' is not assignable to type '(p1: any, p2: any) => boolean'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(92,9): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(93,16): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(94,20): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(100,25): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(101,16): error TS2409: Return type of constructor signature must be assignable to the instance type of the class
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(103,20): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(106,20): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(107,16): error TS2408: Setters cannot return a value.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(112,18): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(116,22): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(120,20): error TS1229: A type predicate cannot reference a rest parameter.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(125,34): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(91,1): error TS2322: Type '(p1: any, p2: any, p3: any) => boolean' is not assignable to type '(p1: any, p2: any) => boolean'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(96,9): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(97,16): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(98,20): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(104,25): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(105,16): error TS2409: Return type of constructor signature must be assignable to the instance type of the class
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(107,20): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(110,20): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(111,16): error TS2408: Setters cannot return a value.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(116,18): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(120,22): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(124,20): error TS1229: A type predicate cannot reference a rest parameter.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(129,34): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(133,39): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(133,34): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(137,39): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
 
 
-==== tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts (30 errors) ====
+==== tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts (31 errors) ====
     
     class A {
         propA: number;
@@ -66,6 +67,12 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(133,39
         return true;
     }
     
+    function hasMissingParameter(): x is A {
+                                    ~
+!!! error TS1225: Cannot find parameter 'x'.
+        return true;
+    }
+    
     function hasMissingTypeInTypeGuardType(x): x is {
              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2391: Function implementation is missing or not immediately following the declaration.
@@ -237,4 +244,10 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(133,39
                                           ~~
 !!! error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
         return true;
+    }
+    
+    // Should not crash the compiler
+    var x: A;
+    if (hasMissingParameter()) {
+        x.propA;
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/typeGuardFunctionErrors.js b/tests/baselines/reference/typeGuardFunctionErrors.js
index 179a3b80cf0..4923f544345 100644
--- a/tests/baselines/reference/typeGuardFunctionErrors.js
+++ b/tests/baselines/reference/typeGuardFunctionErrors.js
@@ -24,6 +24,10 @@ function hasMissingIsKeyword(): x {
     return true;
 }
 
+function hasMissingParameter(): x is A {
+    return true;
+}
+
 function hasMissingTypeInTypeGuardType(x): x is {
     return true;
 }
@@ -133,14 +137,19 @@ function b6([a, b, p1], p2, p3): p1 is A {
 
 function b7({a, b, c: {p1}}, p2, p3): p1 is A {
     return true;
+}
+
+// Should not crash the compiler
+var x: A;
+if (hasMissingParameter()) {
+    x.propA;
 }
 
 //// [typeGuardFunctionErrors.js]
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
@@ -168,6 +177,9 @@ function hasTypeGuardTypeInsideTypeGuardType(x) {
 function hasMissingIsKeyword() {
     return true;
 }
+function hasMissingParameter() {
+    return true;
+}
 return true;
 function hasNonMatchingParameter(y) {
     return true;
@@ -261,3 +273,8 @@ function b7(_a, p2, p3) {
     var a = _a.a, b = _a.b, p1 = _a.c.p1;
     return true;
 }
+// Should not crash the compiler
+var x;
+if (hasMissingParameter()) {
+    x.propA;
+}
diff --git a/tests/baselines/reference/typeGuardFunctionGenerics.js b/tests/baselines/reference/typeGuardFunctionGenerics.js
index 6704225a0d0..edf5cb97fe4 100644
--- a/tests/baselines/reference/typeGuardFunctionGenerics.js
+++ b/tests/baselines/reference/typeGuardFunctionGenerics.js
@@ -37,8 +37,7 @@ let test3: B = funE(isB, 1);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {
diff --git a/tests/baselines/reference/typeGuardOfFormInstanceOf.js b/tests/baselines/reference/typeGuardOfFormInstanceOf.js
index de7e9813a84..cab04365c19 100644
--- a/tests/baselines/reference/typeGuardOfFormInstanceOf.js
+++ b/tests/baselines/reference/typeGuardOfFormInstanceOf.js
@@ -39,8 +39,7 @@ var r2: D1 | C2 = c2Ord1 instanceof C1 && c2Ord1; // C2 | D1
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function () {
     function C1() {
diff --git a/tests/baselines/reference/typeGuardOfFormIsType.js b/tests/baselines/reference/typeGuardOfFormIsType.js
index 65d99319d1e..8400aef59ad 100644
--- a/tests/baselines/reference/typeGuardOfFormIsType.js
+++ b/tests/baselines/reference/typeGuardOfFormIsType.js
@@ -41,8 +41,7 @@ var r2: C2 | D1 = isC1(c2Ord1) && c2Ord1; // C2 | D1
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C1 = (function () {
     function C1() {
diff --git a/tests/baselines/reference/typeMatch2.js b/tests/baselines/reference/typeMatch2.js
index 6f05bf684f1..c4550750ca2 100644
--- a/tests/baselines/reference/typeMatch2.js
+++ b/tests/baselines/reference/typeMatch2.js
@@ -48,8 +48,7 @@ function f4() {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 function f1() {
     var a = { x: 1, y: 2 };
diff --git a/tests/baselines/reference/typeOfSuperCall.js b/tests/baselines/reference/typeOfSuperCall.js
index 5df29d615e4..72cdd7d528e 100644
--- a/tests/baselines/reference/typeOfSuperCall.js
+++ b/tests/baselines/reference/typeOfSuperCall.js
@@ -12,8 +12,7 @@ class D extends C {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/typeParameterAsBaseClass.js b/tests/baselines/reference/typeParameterAsBaseClass.js
index b00a00abac5..f17db28f657 100644
--- a/tests/baselines/reference/typeParameterAsBaseClass.js
+++ b/tests/baselines/reference/typeParameterAsBaseClass.js
@@ -6,8 +6,7 @@ class C2<T> implements T {}
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/typeParameterAsBaseType.js b/tests/baselines/reference/typeParameterAsBaseType.js
index 2715c09fa23..de9a0ed2587 100644
--- a/tests/baselines/reference/typeParameterAsBaseType.js
+++ b/tests/baselines/reference/typeParameterAsBaseType.js
@@ -16,8 +16,7 @@ interface I2<T, U> extends U { }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function (_super) {
     __extends(C, _super);
diff --git a/tests/baselines/reference/typeParameterExtendingUnion1.js b/tests/baselines/reference/typeParameterExtendingUnion1.js
index c5e8fccf350..3027f119fb9 100644
--- a/tests/baselines/reference/typeParameterExtendingUnion1.js
+++ b/tests/baselines/reference/typeParameterExtendingUnion1.js
@@ -16,8 +16,7 @@ function f<T extends Cat | Dog>(a: T) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Animal = (function () {
     function Animal() {
diff --git a/tests/baselines/reference/typeParameterExtendingUnion2.js b/tests/baselines/reference/typeParameterExtendingUnion2.js
index e53aeb42f22..55f6d3e07e2 100644
--- a/tests/baselines/reference/typeParameterExtendingUnion2.js
+++ b/tests/baselines/reference/typeParameterExtendingUnion2.js
@@ -16,8 +16,7 @@ function f<T extends Cat | Dog>(a: T) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Animal = (function () {
     function Animal() {
diff --git a/tests/baselines/reference/typeValueConflict1.js b/tests/baselines/reference/typeValueConflict1.js
index d036d90262f..0a6e92d0d62 100644
--- a/tests/baselines/reference/typeValueConflict1.js
+++ b/tests/baselines/reference/typeValueConflict1.js
@@ -15,8 +15,7 @@ module M2 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M1;
 (function (M1) {
diff --git a/tests/baselines/reference/typeValueConflict2.js b/tests/baselines/reference/typeValueConflict2.js
index c927e70615a..6e925b535a3 100644
--- a/tests/baselines/reference/typeValueConflict2.js
+++ b/tests/baselines/reference/typeValueConflict2.js
@@ -22,8 +22,7 @@ module M3 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M1;
 (function (M1) {
diff --git a/tests/baselines/reference/typeofClass2.js b/tests/baselines/reference/typeofClass2.js
index f4401db1549..d16abbda6e5 100644
--- a/tests/baselines/reference/typeofClass2.js
+++ b/tests/baselines/reference/typeofClass2.js
@@ -25,8 +25,7 @@ var r2: typeof d;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var C = (function () {
     function C(x) {
diff --git a/tests/baselines/reference/typesWithSpecializedCallSignatures.js b/tests/baselines/reference/typesWithSpecializedCallSignatures.js
index 4baa9d71194..3de4134789e 100644
--- a/tests/baselines/reference/typesWithSpecializedCallSignatures.js
+++ b/tests/baselines/reference/typesWithSpecializedCallSignatures.js
@@ -46,8 +46,7 @@ var r3: Base = c.foo('hm');
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/typesWithSpecializedConstructSignatures.js b/tests/baselines/reference/typesWithSpecializedConstructSignatures.js
index 8f64b4be3bf..c66c471b3a1 100644
--- a/tests/baselines/reference/typesWithSpecializedConstructSignatures.js
+++ b/tests/baselines/reference/typesWithSpecializedConstructSignatures.js
@@ -44,8 +44,7 @@ var r3: Base = new a('hm');
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/undeclaredBase.js b/tests/baselines/reference/undeclaredBase.js
index bb78d5995c3..b1efffc0e24 100644
--- a/tests/baselines/reference/undeclaredBase.js
+++ b/tests/baselines/reference/undeclaredBase.js
@@ -7,8 +7,7 @@ module M { export class C extends M.I { } }
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/undefinedIsSubtypeOfEverything.js b/tests/baselines/reference/undefinedIsSubtypeOfEverything.js
index 49877eb62e0..c89c3f65381 100644
--- a/tests/baselines/reference/undefinedIsSubtypeOfEverything.js
+++ b/tests/baselines/reference/undefinedIsSubtypeOfEverything.js
@@ -126,8 +126,7 @@ class D17 extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base() {
diff --git a/tests/baselines/reference/underscoreMapFirst.js b/tests/baselines/reference/underscoreMapFirst.js
index c1839fadfdc..4ee69572f1d 100644
--- a/tests/baselines/reference/underscoreMapFirst.js
+++ b/tests/baselines/reference/underscoreMapFirst.js
@@ -52,8 +52,7 @@ class MyView extends View {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var MyView = (function (_super) {
     __extends(MyView, _super);
diff --git a/tests/baselines/reference/unionTypeEquivalence.js b/tests/baselines/reference/unionTypeEquivalence.js
index 04ee64b73e3..3f4ad647dd5 100644
--- a/tests/baselines/reference/unionTypeEquivalence.js
+++ b/tests/baselines/reference/unionTypeEquivalence.js
@@ -23,8 +23,7 @@ var z1: string | typeof BC;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // A | B is equivalent to A if B is a subtype of A
 var C = (function () {
diff --git a/tests/baselines/reference/unionTypeFromArrayLiteral.js b/tests/baselines/reference/unionTypeFromArrayLiteral.js
index ab43a6273b2..1bfadd68ca6 100644
--- a/tests/baselines/reference/unionTypeFromArrayLiteral.js
+++ b/tests/baselines/reference/unionTypeFromArrayLiteral.js
@@ -31,8 +31,7 @@ var arr9 = [e, f]; // (E|F)[]
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var arr1 = [1, 2]; // number[]
 var arr2 = ["hello", true]; // (string | number)[]
diff --git a/tests/baselines/reference/unionTypesAssignability.js b/tests/baselines/reference/unionTypesAssignability.js
index 7778e1beded..80eafb4f506 100644
--- a/tests/baselines/reference/unionTypesAssignability.js
+++ b/tests/baselines/reference/unionTypesAssignability.js
@@ -76,8 +76,7 @@ function foo<T, U>(t: T, u: U) {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var unionNumberString;
 var C = (function () {
diff --git a/tests/baselines/reference/unknownSymbols1.js b/tests/baselines/reference/unknownSymbols1.js
index 0e081a66b83..cab42726c73 100644
--- a/tests/baselines/reference/unknownSymbols1.js
+++ b/tests/baselines/reference/unknownSymbols1.js
@@ -36,8 +36,7 @@ class C5 {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var x = asdf;
 var y;
diff --git a/tests/baselines/reference/unspecializedConstraints.js b/tests/baselines/reference/unspecializedConstraints.js
index df64daff2bf..ed844f740ba 100644
--- a/tests/baselines/reference/unspecializedConstraints.js
+++ b/tests/baselines/reference/unspecializedConstraints.js
@@ -157,8 +157,7 @@ module ts {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var ts;
 (function (ts) {
diff --git a/tests/baselines/reference/untypedFunctionCallsWithTypeParameters1.js b/tests/baselines/reference/untypedFunctionCallsWithTypeParameters1.js
index 8304aae576f..2f2d4e87c46 100644
--- a/tests/baselines/reference/untypedFunctionCallsWithTypeParameters1.js
+++ b/tests/baselines/reference/untypedFunctionCallsWithTypeParameters1.js
@@ -47,8 +47,7 @@ c5<string>(1); // error
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 // none of these function calls should be allowed
 var x = function () { return; };
diff --git a/tests/baselines/reference/validUseOfThisInSuper.js b/tests/baselines/reference/validUseOfThisInSuper.js
index 6f2fc67d7e1..4378d89ad4b 100644
--- a/tests/baselines/reference/validUseOfThisInSuper.js
+++ b/tests/baselines/reference/validUseOfThisInSuper.js
@@ -13,8 +13,7 @@ class Super extends Base {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Base = (function () {
     function Base(b) {
diff --git a/tests/baselines/reference/varArgsOnConstructorTypes.js b/tests/baselines/reference/varArgsOnConstructorTypes.js
index 005ba55d761..c3daf0c1004 100644
--- a/tests/baselines/reference/varArgsOnConstructorTypes.js
+++ b/tests/baselines/reference/varArgsOnConstructorTypes.js
@@ -28,8 +28,7 @@ reg.register(B);
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 define(["require", "exports"], function (require, exports) {
     var A = (function () {
diff --git a/tests/cases/compiler/classMemberWithMissingIdentifier.ts b/tests/cases/compiler/classMemberWithMissingIdentifier.ts
new file mode 100644
index 00000000000..01ba223f4c4
--- /dev/null
+++ b/tests/cases/compiler/classMemberWithMissingIdentifier.ts
@@ -0,0 +1,3 @@
+class C { 
+    public {};
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/classMemberWithMissingIdentifier2.ts b/tests/cases/compiler/classMemberWithMissingIdentifier2.ts
new file mode 100644
index 00000000000..e1618659797
--- /dev/null
+++ b/tests/cases/compiler/classMemberWithMissingIdentifier2.ts
@@ -0,0 +1,3 @@
+class C { 
+    public {[name:string]:VariableDeclaration};
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/exportSpecifierAndExportedMemberDeclaration.ts b/tests/cases/compiler/exportSpecifierAndExportedMemberDeclaration.ts
new file mode 100644
index 00000000000..1c20ffb0437
--- /dev/null
+++ b/tests/cases/compiler/exportSpecifierAndExportedMemberDeclaration.ts
@@ -0,0 +1,12 @@
+declare module "m2" {
+    export module X {
+        interface I { }
+    }
+    function Y();
+    export { Y as X };
+    function Z(): X.I;
+}
+
+declare module "m2" {
+    function Z2(): X.I;
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/exportSpecifierAndLocalMemberDeclaration.ts b/tests/cases/compiler/exportSpecifierAndLocalMemberDeclaration.ts
new file mode 100644
index 00000000000..5f942a75a74
--- /dev/null
+++ b/tests/cases/compiler/exportSpecifierAndLocalMemberDeclaration.ts
@@ -0,0 +1,12 @@
+declare module "m2" {
+    module X {
+        interface I { }
+    }
+    function Y();
+    export { Y as X };
+    function Z(): X.I;
+}
+
+declare module "m2" {
+    function Z2(): X.I;
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration1.ts b/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration1.ts
new file mode 100644
index 00000000000..e3d0a9000ab
--- /dev/null
+++ b/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration1.ts
@@ -0,0 +1,5 @@
+declare module X { export interface bar { } }
+declare module "m" {
+    export { X };
+    export function foo(): X.bar;
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration2.ts b/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration2.ts
new file mode 100644
index 00000000000..683358a0e3b
--- /dev/null
+++ b/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration2.ts
@@ -0,0 +1,7 @@
+// @module: commonjs
+// @Filename: exportSpecifierReferencingOuterDeclaration2_A.ts
+declare module X { export interface bar { } }
+
+// @Filename: exportSpecifierReferencingOuterDeclaration2_B.ts
+export { X };
+export declare function foo(): X.bar;
\ No newline at end of file
diff --git a/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration3.ts b/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration3.ts
new file mode 100644
index 00000000000..d4ddf3cc4a6
--- /dev/null
+++ b/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration3.ts
@@ -0,0 +1,7 @@
+declare module X { export interface bar { } }
+declare module "m" {
+    module X { export interface foo { } }
+    export { X };
+    export function foo(): X.foo;
+    export function bar(): X.bar; // error
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration4.ts b/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration4.ts
new file mode 100644
index 00000000000..5beaf1de126
--- /dev/null
+++ b/tests/cases/compiler/exportSpecifierReferencingOuterDeclaration4.ts
@@ -0,0 +1,9 @@
+// @module: commonjs
+// @Filename: exportSpecifierReferencingOuterDeclaration2_A.ts
+declare module X { export interface bar { } }
+
+// @Filename: exportSpecifierReferencingOuterDeclaration2_B.ts
+declare module X { export interface foo { } }
+export { X };
+export declare function foo(): X.foo;
+export declare function bar(): X.bar; // error
\ No newline at end of file
diff --git a/tests/cases/compiler/namespacesDeclaration.ts b/tests/cases/compiler/namespacesDeclaration.ts
new file mode 100644
index 00000000000..a231cf2d9d1
--- /dev/null
+++ b/tests/cases/compiler/namespacesDeclaration.ts
@@ -0,0 +1,9 @@
+// @declaration: true
+
+module M {
+   export namespace N {
+      export module M2 {
+         export interface I {}
+      }
+   }
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/systemModule13.ts b/tests/cases/compiler/systemModule13.ts
new file mode 100644
index 00000000000..2f92d99ab21
--- /dev/null
+++ b/tests/cases/compiler/systemModule13.ts
@@ -0,0 +1,5 @@
+// @module: system
+
+export let [x,y,z] = [1, 2, 3];
+export const {a: z0, b: {c: z1}} = {a: true, b: {c: "123"}};
+for ([x] of [[1]]) {}
\ No newline at end of file
diff --git a/tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts b/tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts
index e157b2afe36..688099280c5 100644
--- a/tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts
+++ b/tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts
@@ -23,6 +23,10 @@ function hasMissingIsKeyword(): x {
     return true;
 }
 
+function hasMissingParameter(): x is A {
+    return true;
+}
+
 function hasMissingTypeInTypeGuardType(x): x is {
     return true;
 }
@@ -132,4 +136,10 @@ function b6([a, b, p1], p2, p3): p1 is A {
 
 function b7({a, b, c: {p1}}, p2, p3): p1 is A {
     return true;
+}
+
+// Should not crash the compiler
+var x: A;
+if (hasMissingParameter()) {
+    x.propA;
 }
\ No newline at end of file
diff --git a/tests/cases/fourslash/syntacticClassificationsDocComment3.ts b/tests/cases/fourslash/syntacticClassificationsDocComment3.ts
index bdc7faa470e..6aca8cc415f 100644
--- a/tests/cases/fourslash/syntacticClassificationsDocComment3.ts
+++ b/tests/cases/fourslash/syntacticClassificationsDocComment3.ts
@@ -14,7 +14,6 @@ verify.syntacticClassificationsAre(
     c.punctuation("{"),
     c.keyword("number"),
     c.comment(" /* } */"),
-    c.comment("/* } */"),
     c.keyword("var"),
     c.text("v"),
     c.punctuation(";"));
diff --git a/tests/cases/unittests/incrementalParser.ts b/tests/cases/unittests/incrementalParser.ts
index a0b361a87f4..1ef10eaa712 100644
--- a/tests/cases/unittests/incrementalParser.ts
+++ b/tests/cases/unittests/incrementalParser.ts
@@ -713,6 +713,24 @@ module m3 { }\
             compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, 4);
         });
 
+        it('Do not move constructors from class to object-literal.', () => {
+            var source = "class C { public constructor() { } public constructor() { } public constructor() { } }"
+
+            var oldText = ScriptSnapshot.fromString(source);
+            var newTextAndChange = withChange(oldText, 0, "class C".length, "var v =");
+
+            compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, 0);
+        });
+
+        it('Do not move methods called "constructor" from object literal to class', () => {
+            var source = "var v = { public constructor() { } public constructor() { } public constructor() { } }"
+
+            var oldText = ScriptSnapshot.fromString(source);
+            var newTextAndChange = withChange(oldText, 0, "var v =".length, "class C");
+
+            compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, 0);
+        });
+
         it('Moving index signatures from class to interface',() => {
             var source = "class C { public [a: number]: string; public [a: number]: string; public [a: number]: string }"
 
diff --git a/tests/cases/unittests/transpile.ts b/tests/cases/unittests/transpile.ts
index 06754a5bbc0..fcce034b227 100644
--- a/tests/cases/unittests/transpile.ts
+++ b/tests/cases/unittests/transpile.ts
@@ -68,6 +68,7 @@ var x = 0;`,
                 `});\n`;
             runTest("var x = 1;", { module: ModuleKind.System, newLine: NewLineKind.LineFeed }, /*fileName*/ undefined, "NamedModule", output)
         });
+
         it("No extra errors for file without extension", () => {
             runTest(`var x = 0;`, { module: ModuleKind.CommonJS }, "file", /*moduleName*/undefined, /*expectedOutput*/ undefined, /*expectedDiagnosticCodes*/[]);
         });
diff --git a/tests/cases/unittests/versionCache.ts b/tests/cases/unittests/versionCache.ts
index 12cf9c1b817..06c2cadbfe9 100644
--- a/tests/cases/unittests/versionCache.ts
+++ b/tests/cases/unittests/versionCache.ts
@@ -231,7 +231,7 @@ and grew 1cm per day`;
         });
 
         it("Edit ScriptVersionCache ", () => {
-            let svc = server.ScriptVersionCache.fromString(testContent);
+            let svc = server.ScriptVersionCache.fromString(ts.sys, testContent);
             let checkText = testContent;
 
             for (let i = 0; i < iterationCount; i++) {
diff --git a/tests/perftsc.ts b/tests/perftsc.ts
index e0189896a15..89bff1cc006 100644
--- a/tests/perftsc.ts
+++ b/tests/perftsc.ts
@@ -10,7 +10,7 @@ if (perftest.hasLogIOFlag()) {
             var content = perftest.readFile(s);
             return content !== undefined ? ts.createSourceFile(s, content, v) : undefined;
         },
-        getDefaultLibFilename: () => ts.combinePaths(ts.getDirectoryPath(ts.normalizePath(perftest.getExecutingFilePath())), "lib.d.ts"),
+        getDefaultLibFileName: () => ts.combinePaths(ts.getDirectoryPath(ts.normalizePath(perftest.getExecutingFilePath())), "lib.d.ts"),
         writeFile: (f: string, content: string) => { throw new Error("Unexpected operation: writeFile"); },
         getCurrentDirectory: () => perftest.getCurrentDirectory(),
         getCanonicalFileName: (f: string) => ts.sys.useCaseSensitiveFileNames ? f : f.toLowerCase(),
@@ -19,8 +19,8 @@ if (perftest.hasLogIOFlag()) {
     };
 
     var commandLine = ts.parseCommandLine(perftest.getArgsWithoutLogIOFlag());
-    var program = ts.createProgram(commandLine.filenames, commandLine.options, compilerHost);
-    var fileNames = program.getSourceFiles().map(f => f.filename);
+    var program = ts.createProgram(commandLine.fileNames, commandLine.options, compilerHost);
+    var fileNames = program.getSourceFiles().map(f => f.fileName);
     perftest.writeIOLog(fileNames);
 }
 else {