diff --git a/.travis.yml b/.travis.yml
index 4126683eb62..bfc07e2b510 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,6 +17,8 @@ matrix:
     node_js: stable
     osx_image: xcode7.3
     env: workerCount=2
+  allow_failures:
+  - os: osx
 
 branches:
   only:
@@ -32,3 +34,6 @@ install:
 cache:
   directories:
     - node_modules
+
+git:
+  depth: 1
diff --git a/Gulpfile.ts b/Gulpfile.ts
index b9b5d2068b2..d677b042250 100644
--- a/Gulpfile.ts
+++ b/Gulpfile.ts
@@ -35,6 +35,7 @@ import merge2 = require("merge2");
 import intoStream = require("into-stream");
 import * as os from "os";
 import Linter = require("tslint");
+import fold = require("travis-fold");
 const gulp = helpMaker(originalGulp);
 const mochaParallel = require("./scripts/mocha-parallel.js");
 const {runTestsInParallel} = mochaParallel;
@@ -964,6 +965,7 @@ gulp.task("lint", "Runs tslint on the compiler sources. Optional arguments are:
     const fileMatcher = RegExp(cmdLineOptions["files"]);
     const lintOptions = getLinterOptions();
     let failed = 0;
+    if (fold.isTravis()) console.log(fold.start("lint"));
     return gulp.src(lintTargets)
         .pipe(insert.transform((contents, file) => {
             if (!fileMatcher.test(file.path)) return contents;
@@ -975,6 +977,7 @@ gulp.task("lint", "Runs tslint on the compiler sources. Optional arguments are:
             return contents; // TODO (weswig): Automatically apply fixes? :3
         }))
         .on("end", () => {
+            if (fold.isTravis()) console.log(fold.end("lint"));
             if (failed > 0) {
                 console.error("Linter errors.");
                 process.exit(1);
diff --git a/Jakefile.js b/Jakefile.js
index a5650a56b16..0624c92f162 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -5,6 +5,7 @@ var os = require("os");
 var path = require("path");
 var child_process = require("child_process");
 var Linter = require("tslint");
+var fold = require("travis-fold");
 var runTestsInParallel = require("./scripts/mocha-parallel").runTestsInParallel;
 
 // Variables
@@ -560,9 +561,19 @@ compileFile(
 desc("Builds language service server library");
 task("lssl", [tsserverLibraryFile, tsserverLibraryDefinitionFile]);
 
+desc("Emit the start of the build fold");
+task("build-fold-start", [] , function() {
+    if (fold.isTravis()) console.log(fold.start("build"));
+});
+
+desc("Emit the end of the build fold");
+task("build-fold-end", [] , function() {
+    if (fold.isTravis()) console.log(fold.end("build"));
+});
+
 // Local target to build the compiler and services
 desc("Builds the full compiler and services");
-task("local", ["generate-diagnostics", "lib", tscFile, servicesFile, nodeDefinitionsFile, serverFile, builtGeneratedDiagnosticMessagesJSON, "lssl"]);
+task("local", ["build-fold-start", "generate-diagnostics", "lib", tscFile, servicesFile, nodeDefinitionsFile, serverFile, builtGeneratedDiagnosticMessagesJSON, "lssl", "build-fold-end"]);
 
 // Local target to build only tsc.js
 desc("Builds only the compiler");
@@ -998,12 +1009,22 @@ var tslintRulesOutFiles = tslintRules.map(function(p) {
     return path.join(builtLocalDirectory, "tslint", p + ".js");
 });
 desc("Compiles tslint rules to js");
-task("build-rules", tslintRulesOutFiles);
+task("build-rules", ["build-rules-start"].concat(tslintRulesOutFiles).concat(["build-rules-end"]));
 tslintRulesFiles.forEach(function(ruleFile, i) {
     compileFile(tslintRulesOutFiles[i], [ruleFile], [ruleFile], [], /*useBuiltCompiler*/ false,
     { noOutFile: true, generateDeclarations: false, outDir: path.join(builtLocalDirectory, "tslint")});
 });
 
+desc("Emit the start of the build-rules fold");
+task("build-rules-start", [] , function() {
+    if (fold.isTravis()) console.log(fold.start("build-rules"));
+});
+
+desc("Emit the end of the build-rules fold");
+task("build-rules-end", [] , function() {
+    if (fold.isTravis()) console.log(fold.end("build-rules"));
+});
+
 function getLinterOptions() {
     return {
         configuration: require("./tslint.json"),
@@ -1047,6 +1068,7 @@ var lintTargets = compilerSources
 
 desc("Runs tslint on the compiler sources. Optional arguments are: f[iles]=regex");
 task("lint", ["build-rules"], function() {
+    if (fold.isTravis()) console.log(fold.start("lint"));
     var lintOptions = getLinterOptions();
     var failed = 0;
     var fileMatcher = RegExp(process.env.f || process.env.file || process.env.files || "");
@@ -1062,6 +1084,7 @@ task("lint", ["build-rules"], function() {
             done[target] = true;
         }
     }
+    if (fold.isTravis()) console.log(fold.end("lint"));
     if (failed > 0) {
         fail('Linter errors.', failed);
     }
diff --git a/package.json b/package.json
index 9f3122c3374..25d8f0c42ea 100644
--- a/package.json
+++ b/package.json
@@ -30,8 +30,8 @@
     },
     "devDependencies": {
         "@types/browserify": "latest",
-        "@types/convert-source-map": "latest",
         "@types/chai": "latest",
+        "@types/convert-source-map": "latest",
         "@types/del": "latest",
         "@types/glob": "latest",
         "@types/gulp": "latest",
@@ -72,6 +72,7 @@
         "run-sequence": "latest",
         "sorcery": "latest",
         "through2": "latest",
+        "travis-fold": "latest",
         "ts-node": "latest",
         "tslint": "next",
         "typescript": "next"
diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 2547dd2cd5a..573bd0b7e35 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1900,20 +1900,20 @@ namespace ts {
         }
 
         function bindExportAssignment(node: ExportAssignment | BinaryExpression) {
-            const boundExpression = node.kind === SyntaxKind.ExportAssignment ? (<ExportAssignment>node).expression : (<BinaryExpression>node).right;
             if (!container.symbol || !container.symbol.exports) {
                 // Export assignment in some sort of block construct
                 bindAnonymousDeclaration(node, SymbolFlags.Alias, getDeclarationName(node));
             }
-            else if (boundExpression.kind === SyntaxKind.Identifier && node.kind === SyntaxKind.ExportAssignment) {
-                // An export default clause with an identifier exports all meanings of that identifier
-                declareSymbol(container.symbol.exports, container.symbol, node, SymbolFlags.Alias, SymbolFlags.PropertyExcludes | SymbolFlags.AliasExcludes);
-            }
             else {
                 // An export default clause with an expression exports a value
                 // We want to exclude both class and function here,  this is necessary to issue an error when there are both
                 // default export-assignment and default export function and class declaration.
-                declareSymbol(container.symbol.exports, container.symbol, node, SymbolFlags.Property, SymbolFlags.Class | SymbolFlags.Function | SymbolFlags.Property);
+                const flags = node.kind === SyntaxKind.ExportAssignment && exportAssignmentIsAlias(<ExportAssignment>node)
+                    // An export default clause with an EntityNameExpression exports all meanings of that identifier
+                    ? SymbolFlags.Alias
+                    // An export default clause with any other expression exports a value
+                    : SymbolFlags.Property;
+                declareSymbol(container.symbol.exports, container.symbol, node, flags, SymbolFlags.Property | SymbolFlags.AliasExcludes | SymbolFlags.Class | SymbolFlags.Function); //SymbolFlags.Class | SymbolFlags.Function | SymbolFlags.Property);
             }
         }
 
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 1f2eaea833d..71fdefdc4c9 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -664,7 +664,7 @@ namespace ts {
         // Resolve a given name for a given meaning at a given location. An error is reported if the name was not found and
         // the nameNotFoundMessage argument is not undefined. Returns the resolved symbol, or undefined if no symbol with
         // the given name can be found.
-        function resolveName(location: Node, name: string, meaning: SymbolFlags, nameNotFoundMessage: DiagnosticMessage, nameArg: string | Identifier): Symbol {
+        function resolveName(location: Node | undefined, name: string, meaning: SymbolFlags, nameNotFoundMessage: DiagnosticMessage, nameArg: string | Identifier): Symbol {
             let result: Symbol;
             let lastLocation: Node;
             let propertyWithInvalidInitializer: Node;
@@ -881,7 +881,8 @@ namespace ts {
 
             if (!result) {
                 if (nameNotFoundMessage) {
-                    if (!checkAndReportErrorForMissingPrefix(errorLocation, name, nameArg) &&
+                    if (!errorLocation ||
+                        !checkAndReportErrorForMissingPrefix(errorLocation, name, nameArg) &&
                         !checkAndReportErrorForExtendingInterface(errorLocation)) {
                         error(errorLocation, nameNotFoundMessage, typeof nameArg === "string" ? nameArg : declarationNameToString(nameArg));
                     }
@@ -930,7 +931,7 @@ namespace ts {
         }
 
         function checkAndReportErrorForMissingPrefix(errorLocation: Node, name: string, nameArg: string | Identifier): boolean {
-            if (!errorLocation || (errorLocation.kind === SyntaxKind.Identifier && (isTypeReferenceIdentifier(<Identifier>errorLocation)) || isInTypeQuery(errorLocation))) {
+            if ((errorLocation.kind === SyntaxKind.Identifier && (isTypeReferenceIdentifier(<Identifier>errorLocation)) || isInTypeQuery(errorLocation))) {
                 return false;
             }
 
@@ -968,28 +969,30 @@ namespace ts {
 
 
         function checkAndReportErrorForExtendingInterface(errorLocation: Node): boolean {
-            let parentClassExpression = errorLocation;
-            while (parentClassExpression) {
-                const kind = parentClassExpression.kind;
-                if (kind === SyntaxKind.Identifier || kind === SyntaxKind.PropertyAccessExpression) {
-                    parentClassExpression = parentClassExpression.parent;
-                    continue;
-                }
-                if (kind === SyntaxKind.ExpressionWithTypeArguments) {
-                    break;
-                }
-                return false;
-            }
-            if (!parentClassExpression) {
-                return false;
-            }
-            const expression = (<ExpressionWithTypeArguments>parentClassExpression).expression;
-            if (resolveEntityName(expression, SymbolFlags.Interface, /*ignoreErrors*/ true)) {
+            const expression = getEntityNameForExtendingInterface(errorLocation);
+            const isError = !!(expression && resolveEntityName(expression, SymbolFlags.Interface, /*ignoreErrors*/ true));
+            if (isError) {
                 error(errorLocation, Diagnostics.Cannot_extend_an_interface_0_Did_you_mean_implements, getTextOfNode(expression));
-                return true;
             }
-            return false;
+            return isError;
         }
+        /**
+         * Climbs up parents to an ExpressionWithTypeArguments, and returns its expression,
+         * but returns undefined if that expression is not an EntityNameExpression.
+         */
+        function getEntityNameForExtendingInterface(node: Node): EntityNameExpression | undefined {
+            switch (node.kind) {
+                case SyntaxKind.Identifier:
+                case SyntaxKind.PropertyAccessExpression:
+                    return node.parent ? getEntityNameForExtendingInterface(node.parent) : undefined;
+                case SyntaxKind.ExpressionWithTypeArguments:
+                    Debug.assert(isEntityNameExpression((<ExpressionWithTypeArguments>node).expression));
+                    return <EntityNameExpression>(<ExpressionWithTypeArguments>node).expression;
+                default:
+                    return undefined;
+            }
+        }
+
 
         function checkResolvedBlockScopedVariable(result: Symbol, errorLocation: Node): void {
             Debug.assert((result.flags & SymbolFlags.BlockScopedVariable) !== 0);
@@ -1033,7 +1036,7 @@ namespace ts {
         }
 
         function getDeclarationOfAliasSymbol(symbol: Symbol): Declaration {
-            return forEach(symbol.declarations, d => isAliasSymbolDeclaration(d) ? d : undefined);
+            return find(symbol.declarations, d => isAliasSymbolDeclaration(d) ? d : undefined);
         }
 
         function getTargetOfImportEqualsDeclaration(node: ImportEqualsDeclaration): Symbol {
@@ -1168,7 +1171,7 @@ namespace ts {
         }
 
         function getTargetOfExportAssignment(node: ExportAssignment): Symbol {
-            return resolveEntityName(<Identifier>node.expression, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace);
+            return resolveEntityName(<EntityNameExpression>node.expression, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace);
         }
 
         function getTargetOfAliasDeclaration(node: Declaration): Symbol {
@@ -1278,7 +1281,7 @@ namespace ts {
         }
 
         // Resolves a qualified name and any involved aliases
-        function resolveEntityName(name: EntityName | Expression, meaning: SymbolFlags, ignoreErrors?: boolean, dontResolveAlias?: boolean): Symbol {
+        function resolveEntityName(name: EntityNameOrEntityNameExpression, meaning: SymbolFlags, ignoreErrors?: boolean, dontResolveAlias?: boolean): Symbol | undefined {
             if (nodeIsMissing(name)) {
                 return undefined;
             }
@@ -1293,7 +1296,7 @@ namespace ts {
                 }
             }
             else if (name.kind === SyntaxKind.QualifiedName || name.kind === SyntaxKind.PropertyAccessExpression) {
-                const left = name.kind === SyntaxKind.QualifiedName ? (<QualifiedName>name).left : (<PropertyAccessExpression>name).expression;
+                const left = name.kind === SyntaxKind.QualifiedName ? (<QualifiedName>name).left : (<PropertyAccessEntityNameExpression>name).expression;
                 const right = name.kind === SyntaxKind.QualifiedName ? (<QualifiedName>name).right : (<PropertyAccessExpression>name).name;
 
                 const namespace = resolveEntityName(left, SymbolFlags.Namespace, ignoreErrors);
@@ -1538,8 +1541,8 @@ namespace ts {
 
         function createType(flags: TypeFlags): Type {
             const result = new Type(checker, flags);
-            result.id = typeCount;
             typeCount++;
+            result.id = typeCount;
             return result;
         }
 
@@ -1849,7 +1852,7 @@ namespace ts {
             }
         }
 
-        function isEntityNameVisible(entityName: EntityName | Expression, enclosingDeclaration: Node): SymbolVisibilityResult {
+        function isEntityNameVisible(entityName: EntityNameOrEntityNameExpression, enclosingDeclaration: Node): SymbolVisibilityResult {
             // get symbol of the first identifier of the entityName
             let meaning: SymbolFlags;
             if (entityName.parent.kind === SyntaxKind.TypeQuery || isExpressionWithTypeArgumentsInClassExtendsClause(entityName.parent)) {
@@ -3679,7 +3682,7 @@ namespace ts {
                     const baseTypeNodes = getInterfaceBaseTypeNodes(<InterfaceDeclaration>declaration);
                     if (baseTypeNodes) {
                         for (const node of baseTypeNodes) {
-                            if (isSupportedExpressionWithTypeArguments(node)) {
+                            if (isEntityNameExpression(node.expression)) {
                                 const baseSymbol = resolveEntityName(node.expression, SymbolFlags.Type, /*ignoreErrors*/ true);
                                 if (!baseSymbol || !(baseSymbol.flags & SymbolFlags.Interface) || getDeclaredTypeOfClassOrInterface(baseSymbol).thisType) {
                                     return false;
@@ -4000,6 +4003,9 @@ namespace ts {
                 return createTypeReference((<TypeReference>type).target,
                     concatenate((<TypeReference>type).typeArguments, [thisArgument || (<TypeReference>type).target.thisType]));
             }
+            if (type.flags & TypeFlags.Tuple) {
+                return createTupleType((type as TupleType).elementTypes, thisArgument);
+            }
             return type;
         }
 
@@ -4103,7 +4109,8 @@ namespace ts {
         function resolveTupleTypeMembers(type: TupleType) {
             const arrayElementType = getUnionType(type.elementTypes);
             // Make the tuple type itself the 'this' type by including an extra type argument
-            const arrayType = resolveStructuredTypeMembers(createTypeFromGenericGlobalType(globalArrayType, [arrayElementType, type]));
+            // (Unless it's provided in the case that the tuple is a type parameter constraint)
+            const arrayType = resolveStructuredTypeMembers(createTypeFromGenericGlobalType(globalArrayType, [arrayElementType, type.thisType || type]));
             const members = createTupleTypeMemberSymbols(type.elementTypes);
             addInheritedMembers(members, arrayType.properties);
             setObjectTypeMembers(type, members, arrayType.callSignatures, arrayType.constructSignatures, arrayType.stringIndexInfo, arrayType.numberIndexInfo);
@@ -5041,7 +5048,7 @@ namespace ts {
             return getDeclaredTypeOfSymbol(symbol);
         }
 
-        function getTypeReferenceName(node: TypeReferenceNode | ExpressionWithTypeArguments | JSDocTypeReference): LeftHandSideExpression | EntityName {
+        function getTypeReferenceName(node: TypeReferenceNode | ExpressionWithTypeArguments | JSDocTypeReference): EntityNameOrEntityNameExpression | undefined {
             switch (node.kind) {
                 case SyntaxKind.TypeReference:
                     return (<TypeReferenceNode>node).typeName;
@@ -5050,8 +5057,9 @@ namespace ts {
                 case SyntaxKind.ExpressionWithTypeArguments:
                     // We only support expressions that are simple qualified names. For other
                     // expressions this produces undefined.
-                    if (isSupportedExpressionWithTypeArguments(<ExpressionWithTypeArguments>node)) {
-                        return (<ExpressionWithTypeArguments>node).expression;
+                    const expr = (<ExpressionWithTypeArguments>node).expression;
+                    if (isEntityNameExpression(expr)) {
+                        return expr;
                     }
 
                 // fall through;
@@ -5062,7 +5070,7 @@ namespace ts {
 
         function resolveTypeReferenceName(
             node: TypeReferenceNode | ExpressionWithTypeArguments | JSDocTypeReference,
-            typeReferenceName: LeftHandSideExpression | EntityName) {
+            typeReferenceName: EntityNameExpression | EntityName) {
 
             if (!typeReferenceName) {
                 return unknownSymbol;
@@ -5103,15 +5111,14 @@ namespace ts {
                     const typeReferenceName = getTypeReferenceName(node);
                     symbol = resolveTypeReferenceName(node, typeReferenceName);
                     type = getTypeReferenceType(node, symbol);
-
-                    links.resolvedSymbol = symbol;
-                    links.resolvedType = type;
                 }
                 else {
                     // We only support expressions that are simple qualified names. For other expressions this produces undefined.
-                    const typeNameOrExpression = node.kind === SyntaxKind.TypeReference ? (<TypeReferenceNode>node).typeName :
-                        isSupportedExpressionWithTypeArguments(<ExpressionWithTypeArguments>node) ? (<ExpressionWithTypeArguments>node).expression :
-                            undefined;
+                    const typeNameOrExpression: EntityNameOrEntityNameExpression = node.kind === SyntaxKind.TypeReference
+                        ? (<TypeReferenceNode>node).typeName
+                        : isEntityNameExpression((<ExpressionWithTypeArguments>node).expression)
+                            ? <EntityNameExpression>(<ExpressionWithTypeArguments>node).expression
+                            : undefined;
                     symbol = typeNameOrExpression && resolveEntityName(typeNameOrExpression, SymbolFlags.Type) || unknownSymbol;
                     type = symbol === unknownSymbol ? unknownType :
                         symbol.flags & (SymbolFlags.Class | SymbolFlags.Interface) ? getTypeFromClassOrInterfaceReference(node, symbol) :
@@ -5230,15 +5237,16 @@ namespace ts {
             return links.resolvedType;
         }
 
-        function createTupleType(elementTypes: Type[]) {
-            const id = getTypeListId(elementTypes);
-            return tupleTypes[id] || (tupleTypes[id] = createNewTupleType(elementTypes));
+        function createTupleType(elementTypes: Type[], thisType?: Type) {
+            const id = getTypeListId(elementTypes) + "," + (thisType ? thisType.id : 0);
+            return tupleTypes[id] || (tupleTypes[id] = createNewTupleType(elementTypes, thisType));
         }
 
-        function createNewTupleType(elementTypes: Type[]) {
+        function createNewTupleType(elementTypes: Type[], thisType?: Type) {
             const propagatedFlags = getPropagatingFlagsOfTypes(elementTypes, /*excludeKinds*/ 0);
             const type = <TupleType>createObjectType(TypeFlags.Tuple | propagatedFlags);
             type.elementTypes = elementTypes;
+            type.thisType = thisType;
             return type;
         }
 
@@ -7837,14 +7845,17 @@ namespace ts {
         }
 
         function isDiscriminantProperty(type: Type, name: string) {
-            if (type && type.flags & TypeFlags.Union) {
-                const prop = getPropertyOfType(type, name);
-                if (prop && prop.flags & SymbolFlags.SyntheticProperty) {
-                    if ((<TransientSymbol>prop).isDiscriminantProperty === undefined) {
-                        (<TransientSymbol>prop).isDiscriminantProperty = !(<TransientSymbol>prop).hasCommonType &&
-                            isUnitUnionType(getTypeOfSymbol(prop));
+            if (type) {
+                const nonNullType = getNonNullableType(type);
+                if (nonNullType.flags & TypeFlags.Union) {
+                    const prop = getPropertyOfType(nonNullType, name);
+                    if (prop && prop.flags & SymbolFlags.SyntheticProperty) {
+                        if ((<TransientSymbol>prop).isDiscriminantProperty === undefined) {
+                            (<TransientSymbol>prop).isDiscriminantProperty = !(<TransientSymbol>prop).hasCommonType &&
+                                isUnitUnionType(getTypeOfSymbol(prop));
+                        }
+                        return (<TransientSymbol>prop).isDiscriminantProperty;
                     }
-                    return (<TransientSymbol>prop).isDiscriminantProperty;
                 }
             }
             return false;
@@ -16379,7 +16390,7 @@ namespace ts {
             const implementedTypeNodes = getClassImplementsHeritageClauseElements(node);
             if (implementedTypeNodes) {
                 for (const typeRefNode of implementedTypeNodes) {
-                    if (!isSupportedExpressionWithTypeArguments(typeRefNode)) {
+                    if (!isEntityNameExpression(typeRefNode.expression)) {
                         error(typeRefNode.expression, Diagnostics.A_class_can_only_implement_an_identifier_Slashqualified_name_with_optional_type_arguments);
                     }
                     checkTypeReferenceNode(typeRefNode);
@@ -16621,7 +16632,7 @@ namespace ts {
                 checkObjectTypeForDuplicateDeclarations(node);
             }
             forEach(getInterfaceBaseTypeNodes(node), heritageElement => {
-                if (!isSupportedExpressionWithTypeArguments(heritageElement)) {
+                if (!isEntityNameExpression(heritageElement.expression)) {
                     error(heritageElement.expression, Diagnostics.An_interface_can_only_extend_an_identifier_Slashqualified_name_with_optional_type_arguments);
                 }
                 checkTypeReferenceNode(heritageElement);
@@ -17086,20 +17097,21 @@ namespace ts {
             }
         }
 
-        function getFirstIdentifier(node: EntityName | Expression): Identifier {
-            while (true) {
-                if (node.kind === SyntaxKind.QualifiedName) {
-                    node = (<QualifiedName>node).left;
-                }
-                else if (node.kind === SyntaxKind.PropertyAccessExpression) {
-                    node = (<PropertyAccessExpression>node).expression;
-                }
-                else {
-                    break;
-                }
+        function getFirstIdentifier(node: EntityNameOrEntityNameExpression): Identifier {
+            switch (node.kind) {
+                case SyntaxKind.Identifier:
+                    return <Identifier>node;
+                case SyntaxKind.QualifiedName:
+                    do {
+                        node = (<QualifiedName>node).left;
+                    } while (node.kind !== SyntaxKind.Identifier);
+                    return <Identifier>node;
+                case SyntaxKind.PropertyAccessExpression:
+                    do {
+                        node = (<PropertyAccessEntityNameExpression>node).expression;
+                    } while (node.kind !== SyntaxKind.Identifier);
+                    return <Identifier>node;
             }
-            Debug.assert(node.kind === SyntaxKind.Identifier);
-            return <Identifier>node;
         }
 
         function checkExternalImportOrExportDeclaration(node: ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration): boolean {
@@ -17798,7 +17810,7 @@ namespace ts {
             return getLeftSideOfImportEqualsOrExportAssignment(node) !== undefined;
         }
 
-        function getSymbolOfEntityNameOrPropertyAccessExpression(entityName: EntityName | PropertyAccessExpression): Symbol {
+        function getSymbolOfEntityNameOrPropertyAccessExpression(entityName: EntityName | PropertyAccessExpression): Symbol | undefined {
             if (isDeclarationName(entityName)) {
                 return getSymbolOfNode(entityName.parent);
             }
@@ -17817,22 +17829,20 @@ namespace ts {
                 }
             }
 
-            if (entityName.parent.kind === SyntaxKind.ExportAssignment) {
-                return resolveEntityName(<Identifier>entityName,
+            if (entityName.parent.kind === SyntaxKind.ExportAssignment && isEntityNameExpression(<Identifier | PropertyAccessExpression>entityName)) {
+                return resolveEntityName(<EntityNameExpression>entityName,
                     /*all meanings*/ SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace | SymbolFlags.Alias);
             }
 
-            if (entityName.kind !== SyntaxKind.PropertyAccessExpression) {
-                if (isInRightSideOfImportOrExportAssignment(<EntityName>entityName)) {
-                    // Since we already checked for ExportAssignment, this really could only be an Import
-                    const importEqualsDeclaration = <ImportEqualsDeclaration>getAncestor(entityName, SyntaxKind.ImportEqualsDeclaration);
-                    Debug.assert(importEqualsDeclaration !== undefined);
-                    return getSymbolOfPartOfRightHandSideOfImportEquals(<EntityName>entityName, importEqualsDeclaration, /*dontResolveAlias*/ true);
-                }
+            if (entityName.kind !== SyntaxKind.PropertyAccessExpression && isInRightSideOfImportOrExportAssignment(<EntityName>entityName)) {
+                // Since we already checked for ExportAssignment, this really could only be an Import
+                const importEqualsDeclaration = <ImportEqualsDeclaration>getAncestor(entityName, SyntaxKind.ImportEqualsDeclaration);
+                Debug.assert(importEqualsDeclaration !== undefined);
+                return getSymbolOfPartOfRightHandSideOfImportEquals(<EntityName>entityName, importEqualsDeclaration, /*dontResolveAlias*/ true);
             }
 
             if (isRightSideOfQualifiedNameOrPropertyAccess(entityName)) {
-                entityName = <QualifiedName | PropertyAccessExpression>entityName.parent;
+                entityName = <QualifiedName | PropertyAccessEntityNameExpression>entityName.parent;
             }
 
             if (isHeritageClauseElementIdentifier(<EntityName>entityName)) {
@@ -18545,7 +18555,7 @@ namespace ts {
             };
 
             // defined here to avoid outer scope pollution
-            function getTypeReferenceDirectivesForEntityName(node: EntityName | PropertyAccessExpression): string[] {
+            function getTypeReferenceDirectivesForEntityName(node: EntityNameOrEntityNameExpression): string[] {
                 // program does not have any files with type reference directives - bail out
                 if (!fileToDirective) {
                     return undefined;
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 6c87ad82955..549410159b0 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -81,7 +81,7 @@ namespace ts {
      * returns a truthy value, then returns that value.
      * If no such value is found, the callback is applied to each element of array and undefined is returned.
      */
-    export function forEach<T, U>(array: T[], callback: (element: T, index: number) => U): U {
+    export function forEach<T, U>(array: T[] | undefined, callback: (element: T, index: number) => U | undefined): U | undefined {
         if (array) {
             for (let i = 0, len = array.length; i < len; i++) {
                 const result = callback(array[i], i);
@@ -93,6 +93,17 @@ namespace ts {
         return undefined;
     }
 
+    /** Like `forEach`, but assumes existence of array and fails if no truthy value is found. */
+    export function find<T, U>(array: T[], callback: (element: T, index: number) => U | undefined): U {
+        for (let i = 0, len = array.length; i < len; i++) {
+            const result = callback(array[i], i);
+            if (result) {
+                return result;
+            }
+        }
+        Debug.fail();
+    }
+
     export function contains<T>(array: T[], value: T): boolean {
         if (array) {
             for (const v of array) {
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index d93a8a0aed0..c93784cd9e0 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -441,7 +441,7 @@ namespace ts {
                 }
             }
 
-            function emitEntityName(entityName: EntityName | PropertyAccessExpression) {
+            function emitEntityName(entityName: EntityNameOrEntityNameExpression) {
                 const visibilityResult = resolver.isEntityNameVisible(entityName,
                     // Aliases can be written asynchronously so use correct enclosing declaration
                     entityName.parent.kind === SyntaxKind.ImportEqualsDeclaration ? entityName.parent : enclosingDeclaration);
@@ -452,9 +452,9 @@ namespace ts {
             }
 
             function emitExpressionWithTypeArguments(node: ExpressionWithTypeArguments) {
-                if (isSupportedExpressionWithTypeArguments(node)) {
+                if (isEntityNameExpression(node.expression)) {
                     Debug.assert(node.expression.kind === SyntaxKind.Identifier || node.expression.kind === SyntaxKind.PropertyAccessExpression);
-                    emitEntityName(<Identifier | PropertyAccessExpression>node.expression);
+                    emitEntityName(node.expression);
                     if (node.typeArguments) {
                         write("<");
                         emitCommaList(node.typeArguments, emitType);
@@ -1019,7 +1019,7 @@ namespace ts {
             }
 
             function emitTypeOfTypeReference(node: ExpressionWithTypeArguments) {
-                if (isSupportedExpressionWithTypeArguments(node)) {
+                if (isEntityNameExpression(node.expression)) {
                     emitTypeWithNewGetSymbolAccessibilityDiagnostic(node, getHeritageClauseVisibilityError);
                 }
                 else if (!isImplementsList && node.expression.kind === SyntaxKind.NullKeyword) {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index a6e860450c6..74a47f3dbc2 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -982,13 +982,19 @@ namespace ts {
         multiLine?: boolean;
     }
 
+    export type EntityNameExpression = Identifier | PropertyAccessEntityNameExpression;
+    export type EntityNameOrEntityNameExpression = EntityName | EntityNameExpression;
+
     // @kind(SyntaxKind.PropertyAccessExpression)
     export interface PropertyAccessExpression extends MemberExpression, Declaration {
         expression: LeftHandSideExpression;
         name: Identifier;
     }
-
-    export type IdentifierOrPropertyAccess = Identifier | PropertyAccessExpression;
+    /** Brand for a PropertyAccessExpression which, like a QualifiedName, consists of a sequence of identifiers separated by dots. */
+    export interface PropertyAccessEntityNameExpression extends PropertyAccessExpression {
+        _propertyAccessExpressionLikeQualifiedNameBrand?: any;
+        expression: EntityNameExpression;
+    }
 
     // @kind(SyntaxKind.ElementAccessExpression)
     export interface ElementAccessExpression extends MemberExpression {
@@ -2031,7 +2037,7 @@ namespace ts {
         writeTypeOfExpression(expr: Expression, enclosingDeclaration: Node, flags: TypeFormatFlags, writer: SymbolWriter): void;
         writeBaseConstructorTypeOfClass(node: ClassLikeDeclaration, enclosingDeclaration: Node, flags: TypeFormatFlags, writer: SymbolWriter): void;
         isSymbolAccessible(symbol: Symbol, enclosingDeclaration: Node, meaning: SymbolFlags): SymbolAccessibilityResult;
-        isEntityNameVisible(entityName: EntityName | Expression, enclosingDeclaration: Node): SymbolVisibilityResult;
+        isEntityNameVisible(entityName: EntityNameOrEntityNameExpression, enclosingDeclaration: Node): SymbolVisibilityResult;
         // Returns the constant value this property access resolves to, or 'undefined' for a non-constant
         getConstantValue(node: EnumMember | PropertyAccessExpression | ElementAccessExpression): number;
         getReferencedValueDeclaration(reference: Identifier): Declaration;
@@ -2040,7 +2046,7 @@ namespace ts {
         moduleExportsSomeValue(moduleReferenceExpression: Expression): boolean;
         isArgumentsLocalBinding(node: Identifier): boolean;
         getExternalModuleFileFromDeclaration(declaration: ImportEqualsDeclaration | ImportDeclaration | ExportDeclaration | ModuleDeclaration): SourceFile;
-        getTypeReferenceDirectivesForEntityName(name: EntityName | PropertyAccessExpression): string[];
+        getTypeReferenceDirectivesForEntityName(name: EntityNameOrEntityNameExpression): string[];
         getTypeReferenceDirectivesForSymbol(symbol: Symbol, meaning?: SymbolFlags): string[];
     }
 
@@ -2371,6 +2377,7 @@ namespace ts {
 
     export interface TupleType extends ObjectType {
         elementTypes: Type[];  // Element types
+        thisType?: Type;       // This-type of tuple (only needed for tuples that are constraints of type parameters)
     }
 
     export interface UnionOrIntersectionType extends Type {
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 2cfaf1f5cfb..df9f4f95252 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -1033,14 +1033,14 @@ namespace ts {
             && (<PropertyAccessExpression | ElementAccessExpression>node).expression.kind === SyntaxKind.SuperKeyword;
     }
 
-
-    export function getEntityNameFromTypeNode(node: TypeNode): EntityName | Expression {
+    export function getEntityNameFromTypeNode(node: TypeNode): EntityNameOrEntityNameExpression {
         if (node) {
             switch (node.kind) {
                 case SyntaxKind.TypeReference:
                     return (<TypeReferenceNode>node).typeName;
                 case SyntaxKind.ExpressionWithTypeArguments:
-                    return (<ExpressionWithTypeArguments>node).expression;
+                    Debug.assert(isEntityNameExpression((<ExpressionWithTypeArguments>node).expression));
+                    return <EntityNameExpression>(<ExpressionWithTypeArguments>node).expression;
                 case SyntaxKind.Identifier:
                 case SyntaxKind.QualifiedName:
                     return (<EntityName><Node>node);
@@ -1694,8 +1694,8 @@ namespace ts {
     // import * as <symbol> from ...
     // import { x as <symbol> } from ...
     // export { x as <symbol> } from ...
-    // export = ...
-    // export default ...
+    // export = <EntityNameExpression>
+    // export default <EntityNameExpression>
     export function isAliasSymbolDeclaration(node: Node): boolean {
         return node.kind === SyntaxKind.ImportEqualsDeclaration ||
             node.kind === SyntaxKind.NamespaceExportDeclaration ||
@@ -1703,7 +1703,11 @@ namespace ts {
             node.kind === SyntaxKind.NamespaceImport ||
             node.kind === SyntaxKind.ImportSpecifier ||
             node.kind === SyntaxKind.ExportSpecifier ||
-            node.kind === SyntaxKind.ExportAssignment && (<ExportAssignment>node).expression.kind === SyntaxKind.Identifier;
+            node.kind === SyntaxKind.ExportAssignment && exportAssignmentIsAlias(<ExportAssignment>node);
+    }
+
+    export function exportAssignmentIsAlias(node: ExportAssignment): boolean {
+        return isEntityNameExpression(node.expression);
     }
 
     export function getClassExtendsHeritageClauseElement(node: ClassLikeDeclaration | InterfaceDeclaration) {
@@ -2681,22 +2685,9 @@ namespace ts {
             isClassLike(node.parent.parent);
     }
 
-    // Returns false if this heritage clause element's expression contains something unsupported
-    // (i.e. not a name or dotted name).
-    export function isSupportedExpressionWithTypeArguments(node: ExpressionWithTypeArguments): boolean {
-        return isSupportedExpressionWithTypeArgumentsRest(node.expression);
-    }
-
-    function isSupportedExpressionWithTypeArgumentsRest(node: Expression): boolean {
-        if (node.kind === SyntaxKind.Identifier) {
-            return true;
-        }
-        else if (isPropertyAccessExpression(node)) {
-            return isSupportedExpressionWithTypeArgumentsRest(node.expression);
-        }
-        else {
-            return false;
-        }
+    export function isEntityNameExpression(node: Expression): node is EntityNameExpression {
+        return node.kind === SyntaxKind.Identifier ||
+            node.kind === SyntaxKind.PropertyAccessExpression && isEntityNameExpression((<PropertyAccessExpression>node).expression);
     }
 
     export function isRightSideOfQualifiedNameOrPropertyAccess(node: Node) {
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index f27e7e1c174..e8e0a11f615 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -750,7 +750,7 @@ namespace Harness {
 
             export function readDirectory(path: string, extension?: string[], exclude?: string[], include?: string[]) {
                 const fs = new Utils.VirtualFileSystem(path, useCaseSensitiveFileNames());
-                for (const file in listFiles(path)) {
+                for (const file of listFiles(path)) {
                     fs.addFile(file);
                 }
                 return ts.matchFiles(path, extension, exclude, include, useCaseSensitiveFileNames(), getCurrentDirectory(), path => {
diff --git a/src/harness/unittests/session.ts b/src/harness/unittests/session.ts
index c5285544329..d5e6daa5d60 100644
--- a/src/harness/unittests/session.ts
+++ b/src/harness/unittests/session.ts
@@ -106,7 +106,7 @@ namespace ts.server {
         describe("onMessage", () => {
             it("should not throw when commands are executed with invalid arguments", () => {
                 let i = 0;
-                for (name in CommandNames) {
+                for (const name in CommandNames) {
                     if (!Object.prototype.hasOwnProperty.call(CommandNames, name)) {
                         continue;
                     }
diff --git a/src/lib/es2015.iterable.d.ts b/src/lib/es2015.iterable.d.ts
index e1b9d99762b..de339e2bf2c 100644
--- a/src/lib/es2015.iterable.d.ts
+++ b/src/lib/es2015.iterable.d.ts
@@ -63,6 +63,26 @@ interface ArrayConstructor {
     from<T>(iterable: Iterable<T>): Array<T>;
 }
 
+interface ReadonlyArray<T> {
+    /** Iterator */
+    [Symbol.iterator](): IterableIterator<T>;
+
+    /** 
+      * Returns an array of key, value pairs for every entry in the array
+      */
+    entries(): IterableIterator<[number, T]>;
+
+    /** 
+      * Returns an list of keys in the array
+      */
+    keys(): IterableIterator<number>;
+
+    /** 
+      * Returns an list of values in the array
+      */
+    values(): IterableIterator<T>;
+}
+
 interface IArguments {
     /** Iterator */
     [Symbol.iterator](): IterableIterator<any>;
diff --git a/tests/baselines/reference/discriminantsAndNullOrUndefined.js b/tests/baselines/reference/discriminantsAndNullOrUndefined.js
new file mode 100644
index 00000000000..153950f8ab5
--- /dev/null
+++ b/tests/baselines/reference/discriminantsAndNullOrUndefined.js
@@ -0,0 +1,44 @@
+//// [discriminantsAndNullOrUndefined.ts]
+
+// Repro from #10228
+
+interface A { kind: 'A'; }
+interface B { kind: 'B'; }
+
+type C = A | B | undefined;
+
+function never(_: never): never {
+    throw new Error();
+}
+
+function useA(_: A): void { }
+function useB(_: B): void { }
+
+declare var c: C;
+
+if (c !== undefined) {
+    switch (c.kind) {
+        case 'A': useA(c); break;
+        case 'B': useB(c); break;
+        default: never(c);
+    }
+}
+
+//// [discriminantsAndNullOrUndefined.js]
+// Repro from #10228
+function never(_) {
+    throw new Error();
+}
+function useA(_) { }
+function useB(_) { }
+if (c !== undefined) {
+    switch (c.kind) {
+        case 'A':
+            useA(c);
+            break;
+        case 'B':
+            useB(c);
+            break;
+        default: never(c);
+    }
+}
diff --git a/tests/baselines/reference/discriminantsAndNullOrUndefined.symbols b/tests/baselines/reference/discriminantsAndNullOrUndefined.symbols
new file mode 100644
index 00000000000..3f95fcf3a3f
--- /dev/null
+++ b/tests/baselines/reference/discriminantsAndNullOrUndefined.symbols
@@ -0,0 +1,61 @@
+=== tests/cases/compiler/discriminantsAndNullOrUndefined.ts ===
+
+// Repro from #10228
+
+interface A { kind: 'A'; }
+>A : Symbol(A, Decl(discriminantsAndNullOrUndefined.ts, 0, 0))
+>kind : Symbol(A.kind, Decl(discriminantsAndNullOrUndefined.ts, 3, 13))
+
+interface B { kind: 'B'; }
+>B : Symbol(B, Decl(discriminantsAndNullOrUndefined.ts, 3, 26))
+>kind : Symbol(B.kind, Decl(discriminantsAndNullOrUndefined.ts, 4, 13))
+
+type C = A | B | undefined;
+>C : Symbol(C, Decl(discriminantsAndNullOrUndefined.ts, 4, 26))
+>A : Symbol(A, Decl(discriminantsAndNullOrUndefined.ts, 0, 0))
+>B : Symbol(B, Decl(discriminantsAndNullOrUndefined.ts, 3, 26))
+
+function never(_: never): never {
+>never : Symbol(never, Decl(discriminantsAndNullOrUndefined.ts, 6, 27))
+>_ : Symbol(_, Decl(discriminantsAndNullOrUndefined.ts, 8, 15))
+
+    throw new Error();
+>Error : Symbol(Error, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+}
+
+function useA(_: A): void { }
+>useA : Symbol(useA, Decl(discriminantsAndNullOrUndefined.ts, 10, 1))
+>_ : Symbol(_, Decl(discriminantsAndNullOrUndefined.ts, 12, 14))
+>A : Symbol(A, Decl(discriminantsAndNullOrUndefined.ts, 0, 0))
+
+function useB(_: B): void { }
+>useB : Symbol(useB, Decl(discriminantsAndNullOrUndefined.ts, 12, 29))
+>_ : Symbol(_, Decl(discriminantsAndNullOrUndefined.ts, 13, 14))
+>B : Symbol(B, Decl(discriminantsAndNullOrUndefined.ts, 3, 26))
+
+declare var c: C;
+>c : Symbol(c, Decl(discriminantsAndNullOrUndefined.ts, 15, 11))
+>C : Symbol(C, Decl(discriminantsAndNullOrUndefined.ts, 4, 26))
+
+if (c !== undefined) {
+>c : Symbol(c, Decl(discriminantsAndNullOrUndefined.ts, 15, 11))
+>undefined : Symbol(undefined)
+
+    switch (c.kind) {
+>c.kind : Symbol(kind, Decl(discriminantsAndNullOrUndefined.ts, 3, 13), Decl(discriminantsAndNullOrUndefined.ts, 4, 13))
+>c : Symbol(c, Decl(discriminantsAndNullOrUndefined.ts, 15, 11))
+>kind : Symbol(kind, Decl(discriminantsAndNullOrUndefined.ts, 3, 13), Decl(discriminantsAndNullOrUndefined.ts, 4, 13))
+
+        case 'A': useA(c); break;
+>useA : Symbol(useA, Decl(discriminantsAndNullOrUndefined.ts, 10, 1))
+>c : Symbol(c, Decl(discriminantsAndNullOrUndefined.ts, 15, 11))
+
+        case 'B': useB(c); break;
+>useB : Symbol(useB, Decl(discriminantsAndNullOrUndefined.ts, 12, 29))
+>c : Symbol(c, Decl(discriminantsAndNullOrUndefined.ts, 15, 11))
+
+        default: never(c);
+>never : Symbol(never, Decl(discriminantsAndNullOrUndefined.ts, 6, 27))
+>c : Symbol(c, Decl(discriminantsAndNullOrUndefined.ts, 15, 11))
+    }
+}
diff --git a/tests/baselines/reference/discriminantsAndNullOrUndefined.types b/tests/baselines/reference/discriminantsAndNullOrUndefined.types
new file mode 100644
index 00000000000..7a2918ab83b
--- /dev/null
+++ b/tests/baselines/reference/discriminantsAndNullOrUndefined.types
@@ -0,0 +1,68 @@
+=== tests/cases/compiler/discriminantsAndNullOrUndefined.ts ===
+
+// Repro from #10228
+
+interface A { kind: 'A'; }
+>A : A
+>kind : "A"
+
+interface B { kind: 'B'; }
+>B : B
+>kind : "B"
+
+type C = A | B | undefined;
+>C : C
+>A : A
+>B : B
+
+function never(_: never): never {
+>never : (_: never) => never
+>_ : never
+
+    throw new Error();
+>new Error() : Error
+>Error : ErrorConstructor
+}
+
+function useA(_: A): void { }
+>useA : (_: A) => void
+>_ : A
+>A : A
+
+function useB(_: B): void { }
+>useB : (_: B) => void
+>_ : B
+>B : B
+
+declare var c: C;
+>c : C
+>C : C
+
+if (c !== undefined) {
+>c !== undefined : boolean
+>c : C
+>undefined : undefined
+
+    switch (c.kind) {
+>c.kind : "A" | "B"
+>c : A | B
+>kind : "A" | "B"
+
+        case 'A': useA(c); break;
+>'A' : "A"
+>useA(c) : void
+>useA : (_: A) => void
+>c : A
+
+        case 'B': useB(c); break;
+>'B' : "B"
+>useB(c) : void
+>useB : (_: B) => void
+>c : B
+
+        default: never(c);
+>never(c) : never
+>never : (_: never) => never
+>c : never
+    }
+}
diff --git a/tests/baselines/reference/exportDefaultProperty.js b/tests/baselines/reference/exportDefaultProperty.js
new file mode 100644
index 00000000000..10ba6d6419a
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultProperty.js
@@ -0,0 +1,76 @@
+//// [tests/cases/compiler/exportDefaultProperty.ts] ////
+
+//// [declarations.d.ts]
+// This test is just like exportEqualsProperty, but with `export default`.
+
+declare namespace foo.bar {
+    export type X = number;
+    export const X: number;
+}
+
+declare module "foobar" {
+    export default foo.bar;
+}
+
+declare module "foobarx" {
+    export default foo.bar.X;
+}
+
+//// [a.ts]
+namespace A {
+    export class B { constructor(b: number) {} }
+    export namespace B { export const b: number = 0; }
+}
+export default A.B;
+
+//// [b.ts]
+export default "foo".length;
+
+//// [index.ts]
+/// <reference path="declarations.d.ts" />
+import fooBar from "foobar";
+import X = fooBar.X;
+import X2 from "foobarx";
+const x: X = X;
+const x2: X2 = X2;
+
+import B from "./a";
+const b: B = new B(B.b);
+
+import fooLength from "./b";
+fooLength + 1;
+
+
+//// [a.js]
+"use strict";
+var A;
+(function (A) {
+    var B = (function () {
+        function B(b) {
+        }
+        return B;
+    }());
+    A.B = B;
+    var B;
+    (function (B) {
+        B.b = 0;
+    })(B = A.B || (A.B = {}));
+})(A || (A = {}));
+exports.__esModule = true;
+exports["default"] = A.B;
+//// [b.js]
+"use strict";
+exports.__esModule = true;
+exports["default"] = "foo".length;
+//// [index.js]
+"use strict";
+/// <reference path="declarations.d.ts" />
+var foobar_1 = require("foobar");
+var X = foobar_1["default"].X;
+var foobarx_1 = require("foobarx");
+var x = X;
+var x2 = foobarx_1["default"];
+var a_1 = require("./a");
+var b = new a_1["default"](a_1["default"].b);
+var b_1 = require("./b");
+b_1["default"] + 1;
diff --git a/tests/baselines/reference/exportDefaultProperty.symbols b/tests/baselines/reference/exportDefaultProperty.symbols
new file mode 100644
index 00000000000..f9edcd154cc
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultProperty.symbols
@@ -0,0 +1,92 @@
+=== tests/cases/compiler/index.ts ===
+/// <reference path="declarations.d.ts" />
+import fooBar from "foobar";
+>fooBar : Symbol(fooBar, Decl(index.ts, 1, 6))
+
+import X = fooBar.X;
+>X : Symbol(X, Decl(index.ts, 1, 28))
+>fooBar : Symbol(fooBar, Decl(index.ts, 1, 6))
+>X : Symbol(fooBar.X, Decl(declarations.d.ts, 2, 27), Decl(declarations.d.ts, 4, 16))
+
+import X2 from "foobarx";
+>X2 : Symbol(X2, Decl(index.ts, 3, 6))
+
+const x: X = X;
+>x : Symbol(x, Decl(index.ts, 4, 5))
+>X : Symbol(X, Decl(index.ts, 1, 28))
+>X : Symbol(X, Decl(index.ts, 1, 28))
+
+const x2: X2 = X2;
+>x2 : Symbol(x2, Decl(index.ts, 5, 5))
+>X2 : Symbol(X2, Decl(index.ts, 3, 6))
+>X2 : Symbol(X2, Decl(index.ts, 3, 6))
+
+import B from "./a";
+>B : Symbol(B, Decl(index.ts, 7, 6))
+
+const b: B = new B(B.b);
+>b : Symbol(b, Decl(index.ts, 8, 5))
+>B : Symbol(B, Decl(index.ts, 7, 6))
+>B : Symbol(B, Decl(index.ts, 7, 6))
+>B.b : Symbol(B.b, Decl(a.ts, 2, 37))
+>B : Symbol(B, Decl(index.ts, 7, 6))
+>b : Symbol(B.b, Decl(a.ts, 2, 37))
+
+import fooLength from "./b";
+>fooLength : Symbol(fooLength, Decl(index.ts, 10, 6))
+
+fooLength + 1;
+>fooLength : Symbol(fooLength, Decl(index.ts, 10, 6))
+
+=== tests/cases/compiler/declarations.d.ts ===
+// This test is just like exportEqualsProperty, but with `export default`.
+
+declare namespace foo.bar {
+>foo : Symbol(foo, Decl(declarations.d.ts, 0, 0))
+>bar : Symbol(bar, Decl(declarations.d.ts, 2, 22))
+
+    export type X = number;
+>X : Symbol(X, Decl(declarations.d.ts, 2, 27), Decl(declarations.d.ts, 4, 16))
+
+    export const X: number;
+>X : Symbol(X, Decl(declarations.d.ts, 2, 27), Decl(declarations.d.ts, 4, 16))
+}
+
+declare module "foobar" {
+    export default foo.bar;
+>foo.bar : Symbol(default, Decl(declarations.d.ts, 2, 22))
+>foo : Symbol(foo, Decl(declarations.d.ts, 0, 0))
+>bar : Symbol(default, Decl(declarations.d.ts, 2, 22))
+}
+
+declare module "foobarx" {
+    export default foo.bar.X;
+>foo.bar.X : Symbol(default, Decl(declarations.d.ts, 2, 27), Decl(declarations.d.ts, 4, 16))
+>foo.bar : Symbol(foo.bar, Decl(declarations.d.ts, 2, 22))
+>foo : Symbol(foo, Decl(declarations.d.ts, 0, 0))
+>bar : Symbol(foo.bar, Decl(declarations.d.ts, 2, 22))
+>X : Symbol(default, Decl(declarations.d.ts, 2, 27), Decl(declarations.d.ts, 4, 16))
+}
+
+=== tests/cases/compiler/a.ts ===
+namespace A {
+>A : Symbol(A, Decl(a.ts, 0, 0))
+
+    export class B { constructor(b: number) {} }
+>B : Symbol(B, Decl(a.ts, 0, 13), Decl(a.ts, 1, 48))
+>b : Symbol(b, Decl(a.ts, 1, 33))
+
+    export namespace B { export const b: number = 0; }
+>B : Symbol(B, Decl(a.ts, 0, 13), Decl(a.ts, 1, 48))
+>b : Symbol(b, Decl(a.ts, 2, 37))
+}
+export default A.B;
+>A.B : Symbol(default, Decl(a.ts, 0, 13), Decl(a.ts, 1, 48))
+>A : Symbol(A, Decl(a.ts, 0, 0))
+>B : Symbol(default, Decl(a.ts, 0, 13), Decl(a.ts, 1, 48))
+
+=== tests/cases/compiler/b.ts ===
+export default "foo".length;
+>"foo".length : Symbol(String.length, Decl(lib.d.ts, --, --))
+>length : Symbol(String.length, Decl(lib.d.ts, --, --))
+
diff --git a/tests/baselines/reference/exportDefaultProperty.types b/tests/baselines/reference/exportDefaultProperty.types
new file mode 100644
index 00000000000..47cfabfbc16
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultProperty.types
@@ -0,0 +1,97 @@
+=== tests/cases/compiler/index.ts ===
+/// <reference path="declarations.d.ts" />
+import fooBar from "foobar";
+>fooBar : typeof fooBar
+
+import X = fooBar.X;
+>X : number
+>fooBar : typeof fooBar
+>X : number
+
+import X2 from "foobarx";
+>X2 : number
+
+const x: X = X;
+>x : number
+>X : number
+>X : number
+
+const x2: X2 = X2;
+>x2 : number
+>X2 : number
+>X2 : number
+
+import B from "./a";
+>B : typeof B
+
+const b: B = new B(B.b);
+>b : B
+>B : B
+>new B(B.b) : B
+>B : typeof B
+>B.b : number
+>B : typeof B
+>b : number
+
+import fooLength from "./b";
+>fooLength : number
+
+fooLength + 1;
+>fooLength + 1 : number
+>fooLength : number
+>1 : number
+
+=== tests/cases/compiler/declarations.d.ts ===
+// This test is just like exportEqualsProperty, but with `export default`.
+
+declare namespace foo.bar {
+>foo : typeof foo
+>bar : typeof bar
+
+    export type X = number;
+>X : number
+
+    export const X: number;
+>X : number
+}
+
+declare module "foobar" {
+    export default foo.bar;
+>foo.bar : typeof default
+>foo : typeof foo
+>bar : typeof default
+}
+
+declare module "foobarx" {
+    export default foo.bar.X;
+>foo.bar.X : number
+>foo.bar : typeof foo.bar
+>foo : typeof foo
+>bar : typeof foo.bar
+>X : number
+}
+
+=== tests/cases/compiler/a.ts ===
+namespace A {
+>A : typeof A
+
+    export class B { constructor(b: number) {} }
+>B : B
+>b : number
+
+    export namespace B { export const b: number = 0; }
+>B : typeof B
+>b : number
+>0 : number
+}
+export default A.B;
+>A.B : typeof default
+>A : typeof A
+>B : typeof default
+
+=== tests/cases/compiler/b.ts ===
+export default "foo".length;
+>"foo".length : number
+>"foo" : string
+>length : number
+
diff --git a/tests/baselines/reference/exportEqualsProperty.js b/tests/baselines/reference/exportEqualsProperty.js
new file mode 100644
index 00000000000..2fd8a8c8511
--- /dev/null
+++ b/tests/baselines/reference/exportEqualsProperty.js
@@ -0,0 +1,72 @@
+//// [tests/cases/compiler/exportEqualsProperty.ts] ////
+
+//// [declarations.d.ts]
+// This test is just like exportDefaultProperty, but with `export =`.
+
+declare namespace foo.bar {
+    export type X = number;
+    export const X: number;
+}
+
+declare module "foobar" {
+    export = foo.bar;
+}
+
+declare module "foobarx" {
+    export = foo.bar.X;
+}
+
+//// [a.ts]
+namespace A {
+    export class B { constructor(b: number) {} }
+    export namespace B { export const b: number = 0; }
+}
+export = A.B;
+
+//// [b.ts]
+export = "foo".length;
+
+//// [index.ts]
+/// <reference path="declarations.d.ts" />
+import { X } from "foobar";
+import X2 = require("foobarx");
+const x: X = X;
+const x2: X2 = X2;
+
+import B = require("./a");
+const b: B = new B(B.b);
+
+import fooLength = require("./b");
+fooLength + 1;
+
+
+//// [a.js]
+"use strict";
+var A;
+(function (A) {
+    var B = (function () {
+        function B(b) {
+        }
+        return B;
+    }());
+    A.B = B;
+    var B;
+    (function (B) {
+        B.b = 0;
+    })(B = A.B || (A.B = {}));
+})(A || (A = {}));
+module.exports = A.B;
+//// [b.js]
+"use strict";
+module.exports = "foo".length;
+//// [index.js]
+"use strict";
+/// <reference path="declarations.d.ts" />
+var foobar_1 = require("foobar");
+var X2 = require("foobarx");
+var x = foobar_1.X;
+var x2 = X2;
+var B = require("./a");
+var b = new B(B.b);
+var fooLength = require("./b");
+fooLength + 1;
diff --git a/tests/baselines/reference/exportEqualsProperty.symbols b/tests/baselines/reference/exportEqualsProperty.symbols
new file mode 100644
index 00000000000..43c9ed32518
--- /dev/null
+++ b/tests/baselines/reference/exportEqualsProperty.symbols
@@ -0,0 +1,87 @@
+=== tests/cases/compiler/index.ts ===
+/// <reference path="declarations.d.ts" />
+import { X } from "foobar";
+>X : Symbol(X, Decl(index.ts, 1, 8))
+
+import X2 = require("foobarx");
+>X2 : Symbol(X2, Decl(index.ts, 1, 27))
+
+const x: X = X;
+>x : Symbol(x, Decl(index.ts, 3, 5))
+>X : Symbol(X, Decl(index.ts, 1, 8))
+>X : Symbol(X, Decl(index.ts, 1, 8))
+
+const x2: X2 = X2;
+>x2 : Symbol(x2, Decl(index.ts, 4, 5))
+>X2 : Symbol(X2, Decl(index.ts, 1, 27))
+>X2 : Symbol(X2, Decl(index.ts, 1, 27))
+
+import B = require("./a");
+>B : Symbol(B, Decl(index.ts, 4, 18))
+
+const b: B = new B(B.b);
+>b : Symbol(b, Decl(index.ts, 7, 5))
+>B : Symbol(B, Decl(index.ts, 4, 18))
+>B : Symbol(B, Decl(index.ts, 4, 18))
+>B.b : Symbol(B.b, Decl(a.ts, 2, 37))
+>B : Symbol(B, Decl(index.ts, 4, 18))
+>b : Symbol(B.b, Decl(a.ts, 2, 37))
+
+import fooLength = require("./b");
+>fooLength : Symbol(fooLength, Decl(index.ts, 7, 24))
+
+fooLength + 1;
+>fooLength : Symbol(fooLength, Decl(index.ts, 7, 24))
+
+=== tests/cases/compiler/declarations.d.ts ===
+// This test is just like exportDefaultProperty, but with `export =`.
+
+declare namespace foo.bar {
+>foo : Symbol(foo, Decl(declarations.d.ts, 0, 0))
+>bar : Symbol(bar, Decl(declarations.d.ts, 2, 22))
+
+    export type X = number;
+>X : Symbol(X, Decl(declarations.d.ts, 2, 27), Decl(declarations.d.ts, 4, 16))
+
+    export const X: number;
+>X : Symbol(X, Decl(declarations.d.ts, 2, 27), Decl(declarations.d.ts, 4, 16))
+}
+
+declare module "foobar" {
+    export = foo.bar;
+>foo.bar : Symbol(foo.bar, Decl(declarations.d.ts, 2, 22))
+>foo : Symbol(foo, Decl(declarations.d.ts, 0, 0))
+>bar : Symbol(foo.bar, Decl(declarations.d.ts, 2, 22))
+}
+
+declare module "foobarx" {
+    export = foo.bar.X;
+>foo.bar.X : Symbol(foo.bar.X, Decl(declarations.d.ts, 2, 27), Decl(declarations.d.ts, 4, 16))
+>foo.bar : Symbol(foo.bar, Decl(declarations.d.ts, 2, 22))
+>foo : Symbol(foo, Decl(declarations.d.ts, 0, 0))
+>bar : Symbol(foo.bar, Decl(declarations.d.ts, 2, 22))
+>X : Symbol(foo.bar.X, Decl(declarations.d.ts, 2, 27), Decl(declarations.d.ts, 4, 16))
+}
+
+=== tests/cases/compiler/a.ts ===
+namespace A {
+>A : Symbol(A, Decl(a.ts, 0, 0))
+
+    export class B { constructor(b: number) {} }
+>B : Symbol(B, Decl(a.ts, 0, 13), Decl(a.ts, 1, 48))
+>b : Symbol(b, Decl(a.ts, 1, 33))
+
+    export namespace B { export const b: number = 0; }
+>B : Symbol(B, Decl(a.ts, 0, 13), Decl(a.ts, 1, 48))
+>b : Symbol(b, Decl(a.ts, 2, 37))
+}
+export = A.B;
+>A.B : Symbol(A.B, Decl(a.ts, 0, 13), Decl(a.ts, 1, 48))
+>A : Symbol(A, Decl(a.ts, 0, 0))
+>B : Symbol(A.B, Decl(a.ts, 0, 13), Decl(a.ts, 1, 48))
+
+=== tests/cases/compiler/b.ts ===
+export = "foo".length;
+>"foo".length : Symbol(String.length, Decl(lib.d.ts, --, --))
+>length : Symbol(String.length, Decl(lib.d.ts, --, --))
+
diff --git a/tests/baselines/reference/exportEqualsProperty.types b/tests/baselines/reference/exportEqualsProperty.types
new file mode 100644
index 00000000000..a92af53b12b
--- /dev/null
+++ b/tests/baselines/reference/exportEqualsProperty.types
@@ -0,0 +1,92 @@
+=== tests/cases/compiler/index.ts ===
+/// <reference path="declarations.d.ts" />
+import { X } from "foobar";
+>X : number
+
+import X2 = require("foobarx");
+>X2 : number
+
+const x: X = X;
+>x : number
+>X : number
+>X : number
+
+const x2: X2 = X2;
+>x2 : number
+>X2 : number
+>X2 : number
+
+import B = require("./a");
+>B : typeof B
+
+const b: B = new B(B.b);
+>b : B
+>B : B
+>new B(B.b) : B
+>B : typeof B
+>B.b : number
+>B : typeof B
+>b : number
+
+import fooLength = require("./b");
+>fooLength : number
+
+fooLength + 1;
+>fooLength + 1 : number
+>fooLength : number
+>1 : number
+
+=== tests/cases/compiler/declarations.d.ts ===
+// This test is just like exportDefaultProperty, but with `export =`.
+
+declare namespace foo.bar {
+>foo : typeof foo
+>bar : typeof bar
+
+    export type X = number;
+>X : number
+
+    export const X: number;
+>X : number
+}
+
+declare module "foobar" {
+    export = foo.bar;
+>foo.bar : typeof foo.bar
+>foo : typeof foo
+>bar : typeof foo.bar
+}
+
+declare module "foobarx" {
+    export = foo.bar.X;
+>foo.bar.X : number
+>foo.bar : typeof foo.bar
+>foo : typeof foo
+>bar : typeof foo.bar
+>X : number
+}
+
+=== tests/cases/compiler/a.ts ===
+namespace A {
+>A : typeof A
+
+    export class B { constructor(b: number) {} }
+>B : B
+>b : number
+
+    export namespace B { export const b: number = 0; }
+>B : typeof B
+>b : number
+>0 : number
+}
+export = A.B;
+>A.B : typeof A.B
+>A : typeof A
+>B : typeof A.B
+
+=== tests/cases/compiler/b.ts ===
+export = "foo".length;
+>"foo".length : number
+>"foo" : string
+>length : number
+
diff --git a/tests/baselines/reference/thisInTupleTypeParameterConstraints.js b/tests/baselines/reference/thisInTupleTypeParameterConstraints.js
new file mode 100644
index 00000000000..c63fbf61991
--- /dev/null
+++ b/tests/baselines/reference/thisInTupleTypeParameterConstraints.js
@@ -0,0 +1,29 @@
+//// [thisInTupleTypeParameterConstraints.ts]
+/// <reference no-default-lib="true"/>
+
+interface Boolean {}
+interface IArguments {}
+interface Function {}
+interface Number {}
+interface RegExp {}
+interface Object {}
+interface String {}
+
+interface Array<T> {
+    // 4 methods will run out of memory if this-types are not instantiated
+    // correctly for tuple types that are type parameter constraints
+    map<U>(arg: this): void;
+    reduceRight<U>(arg: this): void;
+    reduce<U>(arg: this): void;
+    reduce2<U>(arg: this): void;
+}
+
+declare function f<T extends [(x: number) => number]>(a: T): void;
+let x: [(x: number) => number];
+f(x);
+
+
+//// [thisInTupleTypeParameterConstraints.js]
+/// <reference no-default-lib="true"/>
+var x;
+f(x);
diff --git a/tests/baselines/reference/thisInTupleTypeParameterConstraints.symbols b/tests/baselines/reference/thisInTupleTypeParameterConstraints.symbols
new file mode 100644
index 00000000000..4d2bef22c55
--- /dev/null
+++ b/tests/baselines/reference/thisInTupleTypeParameterConstraints.symbols
@@ -0,0 +1,66 @@
+=== tests/cases/compiler/thisInTupleTypeParameterConstraints.ts ===
+/// <reference no-default-lib="true"/>
+
+interface Boolean {}
+>Boolean : Symbol(Boolean, Decl(thisInTupleTypeParameterConstraints.ts, 0, 0))
+
+interface IArguments {}
+>IArguments : Symbol(IArguments, Decl(thisInTupleTypeParameterConstraints.ts, 2, 20))
+
+interface Function {}
+>Function : Symbol(Function, Decl(thisInTupleTypeParameterConstraints.ts, 3, 23))
+
+interface Number {}
+>Number : Symbol(Number, Decl(thisInTupleTypeParameterConstraints.ts, 4, 21))
+
+interface RegExp {}
+>RegExp : Symbol(RegExp, Decl(thisInTupleTypeParameterConstraints.ts, 5, 19))
+
+interface Object {}
+>Object : Symbol(Object, Decl(thisInTupleTypeParameterConstraints.ts, 6, 19))
+
+interface String {}
+>String : Symbol(String, Decl(thisInTupleTypeParameterConstraints.ts, 7, 19))
+
+interface Array<T> {
+>Array : Symbol(Array, Decl(thisInTupleTypeParameterConstraints.ts, 8, 19))
+>T : Symbol(T, Decl(thisInTupleTypeParameterConstraints.ts, 10, 16))
+
+    // 4 methods will run out of memory if this-types are not instantiated
+    // correctly for tuple types that are type parameter constraints
+    map<U>(arg: this): void;
+>map : Symbol(Array.map, Decl(thisInTupleTypeParameterConstraints.ts, 10, 20))
+>U : Symbol(U, Decl(thisInTupleTypeParameterConstraints.ts, 13, 8))
+>arg : Symbol(arg, Decl(thisInTupleTypeParameterConstraints.ts, 13, 11))
+
+    reduceRight<U>(arg: this): void;
+>reduceRight : Symbol(Array.reduceRight, Decl(thisInTupleTypeParameterConstraints.ts, 13, 28))
+>U : Symbol(U, Decl(thisInTupleTypeParameterConstraints.ts, 14, 16))
+>arg : Symbol(arg, Decl(thisInTupleTypeParameterConstraints.ts, 14, 19))
+
+    reduce<U>(arg: this): void;
+>reduce : Symbol(Array.reduce, Decl(thisInTupleTypeParameterConstraints.ts, 14, 36))
+>U : Symbol(U, Decl(thisInTupleTypeParameterConstraints.ts, 15, 11))
+>arg : Symbol(arg, Decl(thisInTupleTypeParameterConstraints.ts, 15, 14))
+
+    reduce2<U>(arg: this): void;
+>reduce2 : Symbol(Array.reduce2, Decl(thisInTupleTypeParameterConstraints.ts, 15, 31))
+>U : Symbol(U, Decl(thisInTupleTypeParameterConstraints.ts, 16, 12))
+>arg : Symbol(arg, Decl(thisInTupleTypeParameterConstraints.ts, 16, 15))
+}
+
+declare function f<T extends [(x: number) => number]>(a: T): void;
+>f : Symbol(f, Decl(thisInTupleTypeParameterConstraints.ts, 17, 1))
+>T : Symbol(T, Decl(thisInTupleTypeParameterConstraints.ts, 19, 19))
+>x : Symbol(x, Decl(thisInTupleTypeParameterConstraints.ts, 19, 31))
+>a : Symbol(a, Decl(thisInTupleTypeParameterConstraints.ts, 19, 54))
+>T : Symbol(T, Decl(thisInTupleTypeParameterConstraints.ts, 19, 19))
+
+let x: [(x: number) => number];
+>x : Symbol(x, Decl(thisInTupleTypeParameterConstraints.ts, 20, 3))
+>x : Symbol(x, Decl(thisInTupleTypeParameterConstraints.ts, 20, 9))
+
+f(x);
+>f : Symbol(f, Decl(thisInTupleTypeParameterConstraints.ts, 17, 1))
+>x : Symbol(x, Decl(thisInTupleTypeParameterConstraints.ts, 20, 3))
+
diff --git a/tests/baselines/reference/thisInTupleTypeParameterConstraints.types b/tests/baselines/reference/thisInTupleTypeParameterConstraints.types
new file mode 100644
index 00000000000..7daafe02bfc
--- /dev/null
+++ b/tests/baselines/reference/thisInTupleTypeParameterConstraints.types
@@ -0,0 +1,67 @@
+=== tests/cases/compiler/thisInTupleTypeParameterConstraints.ts ===
+/// <reference no-default-lib="true"/>
+
+interface Boolean {}
+>Boolean : Boolean
+
+interface IArguments {}
+>IArguments : IArguments
+
+interface Function {}
+>Function : Function
+
+interface Number {}
+>Number : Number
+
+interface RegExp {}
+>RegExp : RegExp
+
+interface Object {}
+>Object : Object
+
+interface String {}
+>String : String
+
+interface Array<T> {
+>Array : T[]
+>T : T
+
+    // 4 methods will run out of memory if this-types are not instantiated
+    // correctly for tuple types that are type parameter constraints
+    map<U>(arg: this): void;
+>map : <U>(arg: this) => void
+>U : U
+>arg : this
+
+    reduceRight<U>(arg: this): void;
+>reduceRight : <U>(arg: this) => void
+>U : U
+>arg : this
+
+    reduce<U>(arg: this): void;
+>reduce : <U>(arg: this) => void
+>U : U
+>arg : this
+
+    reduce2<U>(arg: this): void;
+>reduce2 : <U>(arg: this) => void
+>U : U
+>arg : this
+}
+
+declare function f<T extends [(x: number) => number]>(a: T): void;
+>f : <T extends [(x: number) => number]>(a: T) => void
+>T : T
+>x : number
+>a : T
+>T : T
+
+let x: [(x: number) => number];
+>x : [(x: number) => number]
+>x : number
+
+f(x);
+>f(x) : void
+>f : <T extends [(x: number) => number]>(a: T) => void
+>x : [(x: number) => number]
+
diff --git a/tests/cases/compiler/discriminantsAndNullOrUndefined.ts b/tests/cases/compiler/discriminantsAndNullOrUndefined.ts
new file mode 100644
index 00000000000..8346fa8adea
--- /dev/null
+++ b/tests/cases/compiler/discriminantsAndNullOrUndefined.ts
@@ -0,0 +1,25 @@
+// @strictNullChecks: true
+
+// Repro from #10228
+
+interface A { kind: 'A'; }
+interface B { kind: 'B'; }
+
+type C = A | B | undefined;
+
+function never(_: never): never {
+    throw new Error();
+}
+
+function useA(_: A): void { }
+function useB(_: B): void { }
+
+declare var c: C;
+
+if (c !== undefined) {
+    switch (c.kind) {
+        case 'A': useA(c); break;
+        case 'B': useB(c); break;
+        default: never(c);
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/exportDefaultProperty.ts b/tests/cases/compiler/exportDefaultProperty.ts
new file mode 100644
index 00000000000..4a4b4139025
--- /dev/null
+++ b/tests/cases/compiler/exportDefaultProperty.ts
@@ -0,0 +1,39 @@
+// This test is just like exportEqualsProperty, but with `export default`.
+
+// @Filename: declarations.d.ts
+declare namespace foo.bar {
+    export type X = number;
+    export const X: number;
+}
+
+declare module "foobar" {
+    export default foo.bar;
+}
+
+declare module "foobarx" {
+    export default foo.bar.X;
+}
+
+// @Filename: a.ts
+namespace A {
+    export class B { constructor(b: number) {} }
+    export namespace B { export const b: number = 0; }
+}
+export default A.B;
+
+// @Filename: b.ts
+export default "foo".length;
+
+// @Filename: index.ts
+/// <reference path="declarations.d.ts" />
+import fooBar from "foobar";
+import X = fooBar.X;
+import X2 from "foobarx";
+const x: X = X;
+const x2: X2 = X2;
+
+import B from "./a";
+const b: B = new B(B.b);
+
+import fooLength from "./b";
+fooLength + 1;
diff --git a/tests/cases/compiler/exportEqualsProperty.ts b/tests/cases/compiler/exportEqualsProperty.ts
new file mode 100644
index 00000000000..0d14815a5bd
--- /dev/null
+++ b/tests/cases/compiler/exportEqualsProperty.ts
@@ -0,0 +1,38 @@
+// This test is just like exportDefaultProperty, but with `export =`.
+
+// @Filename: declarations.d.ts
+declare namespace foo.bar {
+    export type X = number;
+    export const X: number;
+}
+
+declare module "foobar" {
+    export = foo.bar;
+}
+
+declare module "foobarx" {
+    export = foo.bar.X;
+}
+
+// @Filename: a.ts
+namespace A {
+    export class B { constructor(b: number) {} }
+    export namespace B { export const b: number = 0; }
+}
+export = A.B;
+
+// @Filename: b.ts
+export = "foo".length;
+
+// @Filename: index.ts
+/// <reference path="declarations.d.ts" />
+import { X } from "foobar";
+import X2 = require("foobarx");
+const x: X = X;
+const x2: X2 = X2;
+
+import B = require("./a");
+const b: B = new B(B.b);
+
+import fooLength = require("./b");
+fooLength + 1;
diff --git a/tests/cases/compiler/thisInTupleTypeParameterConstraints.ts b/tests/cases/compiler/thisInTupleTypeParameterConstraints.ts
new file mode 100644
index 00000000000..b6d0d338d85
--- /dev/null
+++ b/tests/cases/compiler/thisInTupleTypeParameterConstraints.ts
@@ -0,0 +1,22 @@
+/// <reference no-default-lib="true"/>
+
+interface Boolean {}
+interface IArguments {}
+interface Function {}
+interface Number {}
+interface RegExp {}
+interface Object {}
+interface String {}
+
+interface Array<T> {
+    // 4 methods will run out of memory if this-types are not instantiated
+    // correctly for tuple types that are type parameter constraints
+    map<U>(arg: this): void;
+    reduceRight<U>(arg: this): void;
+    reduce<U>(arg: this): void;
+    reduce2<U>(arg: this): void;
+}
+
+declare function f<T extends [(x: number) => number]>(a: T): void;
+let x: [(x: number) => number];
+f(x);