diff --git a/lib/tsc.js b/lib/tsc.js
index 98d68cec8fb..d412ef7a92d 100644
--- a/lib/tsc.js
+++ b/lib/tsc.js
@@ -1534,7 +1534,6 @@ var ts;
         Merged_declaration_0_cannot_include_a_default_export_declaration_Consider_adding_a_separate_export_default_0_declaration_instead: { code: 2652, category: ts.DiagnosticCategory.Error, key: "Merged declaration '{0}' cannot include a default export declaration. Consider adding a separate 'export default {0}' declaration instead." },
         Non_abstract_class_expression_does_not_implement_inherited_abstract_member_0_from_class_1: { code: 2653, category: ts.DiagnosticCategory.Error, key: "Non-abstract class expression does not implement inherited abstract member '{0}' from class '{1}'." },
         Exported_external_package_typings_file_cannot_contain_tripleslash_references_Please_contact_the_package_author_to_update_the_package_definition: { code: 2654, category: ts.DiagnosticCategory.Error, key: "Exported external package typings file cannot contain tripleslash references. Please contact the package author to update the package definition." },
-        Exported_external_package_typings_can_only_be_in_d_ts_files_Please_contact_the_package_author_to_update_the_package_definition: { code: 2655, category: ts.DiagnosticCategory.Error, key: "Exported external package typings can only be in '.d.ts' files. Please contact the package author to update the package definition." },
         Exported_external_package_typings_file_0_is_not_a_module_Please_contact_the_package_author_to_update_the_package_definition: { code: 2656, category: ts.DiagnosticCategory.Error, key: "Exported external package typings file '{0}' is not a module. Please contact the package author to update the package definition." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: ts.DiagnosticCategory.Error, key: "Import declaration '{0}' is using private name '{1}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: { code: 4002, category: ts.DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
@@ -12631,22 +12630,27 @@ var ts;
             }
             return type.resolvedBaseConstructorType;
         }
+        function hasClassBaseType(type) {
+            return !!ts.forEach(getBaseTypes(type), function (t) { return !!(t.symbol.flags & 32); });
+        }
         function getBaseTypes(type) {
+            var isClass = type.symbol.flags & 32;
+            var isInterface = type.symbol.flags & 64;
             if (!type.resolvedBaseTypes) {
-                if (type.symbol.flags & 32) {
+                if (!isClass && !isInterface) {
+                    ts.Debug.fail("type must be class or interface");
+                }
+                if (isClass) {
                     resolveBaseTypesOfClass(type);
                 }
-                else if (type.symbol.flags & 64) {
+                if (isInterface) {
                     resolveBaseTypesOfInterface(type);
                 }
-                else {
-                    ts.Debug.fail("type must be class or interface");
-                }
             }
             return type.resolvedBaseTypes;
         }
         function resolveBaseTypesOfClass(type) {
-            type.resolvedBaseTypes = emptyArray;
+            type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray;
             var baseContructorType = getBaseConstructorTypeOfClass(type);
             if (!(baseContructorType.flags & 80896)) {
                 return;
@@ -12675,10 +12679,15 @@ var ts;
                 error(type.symbol.valueDeclaration, ts.Diagnostics.Type_0_recursively_references_itself_as_a_base_type, typeToString(type, undefined, 1));
                 return;
             }
-            type.resolvedBaseTypes = [baseType];
+            if (type.resolvedBaseTypes === emptyArray) {
+                type.resolvedBaseTypes = [baseType];
+            }
+            else {
+                type.resolvedBaseTypes.push(baseType);
+            }
         }
         function resolveBaseTypesOfInterface(type) {
-            type.resolvedBaseTypes = [];
+            type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray;
             for (var _i = 0, _a = type.symbol.declarations; _i < _a.length; _i++) {
                 var declaration = _a[_i];
                 if (declaration.kind === 215 && ts.getInterfaceBaseTypeNodes(declaration)) {
@@ -12688,7 +12697,12 @@ var ts;
                         if (baseType !== unknownType) {
                             if (getTargetType(baseType).flags & (1024 | 2048)) {
                                 if (type !== baseType && !hasBaseType(baseType, type)) {
-                                    type.resolvedBaseTypes.push(baseType);
+                                    if (type.resolvedBaseTypes === emptyArray) {
+                                        type.resolvedBaseTypes = [baseType];
+                                    }
+                                    else {
+                                        type.resolvedBaseTypes.push(baseType);
+                                    }
                                 }
                                 else {
                                     error(declaration, ts.Diagnostics.Type_0_recursively_references_itself_as_a_base_type, typeToString(type, undefined, 1));
@@ -12986,7 +13000,7 @@ var ts;
             return createSignature(sig.declaration, sig.typeParameters, sig.parameters, sig.resolvedReturnType, sig.typePredicate, sig.minArgumentCount, sig.hasRestParameter, sig.hasStringLiterals);
         }
         function getDefaultConstructSignatures(classType) {
-            if (!getBaseTypes(classType).length) {
+            if (!hasClassBaseType(classType)) {
                 return [createSignature(undefined, classType.localTypeParameters, emptyArray, classType, undefined, 0, false, false)];
             }
             var baseConstructorType = getBaseConstructorTypeOfClass(classType);
@@ -14967,11 +14981,10 @@ var ts;
             }
             source = getErasedSignature(source);
             target = getErasedSignature(target);
-            var sourceLen = source.parameters.length;
             var targetLen = target.parameters.length;
             for (var i = 0; i < targetLen; i++) {
-                var s = source.hasRestParameter && i === sourceLen - 1 ? getRestTypeOfSignature(source) : getTypeOfSymbol(source.parameters[i]);
-                var t = target.hasRestParameter && i === targetLen - 1 ? getRestTypeOfSignature(target) : getTypeOfSymbol(target.parameters[i]);
+                var s = isRestParameterIndex(source, i) ? getRestTypeOfSignature(source) : getTypeOfSymbol(source.parameters[i]);
+                var t = isRestParameterIndex(target, i) ? getRestTypeOfSignature(target) : getTypeOfSymbol(target.parameters[i]);
                 var related = compareTypes(s, t);
                 if (!related) {
                     return 0;
@@ -14983,6 +14996,9 @@ var ts;
             }
             return result;
         }
+        function isRestParameterIndex(signature, parameterIndex) {
+            return signature.hasRestParameter && parameterIndex >= signature.parameters.length - 1;
+        }
         function isSupertypeOfEach(candidate, types) {
             for (var _i = 0; _i < types.length; _i++) {
                 var type = types[_i];
@@ -15921,8 +15937,9 @@ var ts;
                         if (indexOfParameter < len) {
                             return getTypeAtPosition(contextualSignature, indexOfParameter);
                         }
-                        if (indexOfParameter === (func.parameters.length - 1) &&
-                            funcHasRestParameters && contextualSignature.hasRestParameter && func.parameters.length >= contextualSignature.parameters.length) {
+                        if (funcHasRestParameters &&
+                            indexOfParameter === (func.parameters.length - 1) &&
+                            isRestParameterIndex(contextualSignature, func.parameters.length - 1)) {
                             return getTypeOfSymbol(ts.lastOrUndefined(contextualSignature.parameters));
                         }
                     }
@@ -17042,7 +17059,7 @@ var ts;
                 return false;
             }
             if (spreadArgIndex >= 0) {
-                return signature.hasRestParameter && spreadArgIndex >= signature.parameters.length - 1;
+                return isRestParameterIndex(signature, spreadArgIndex);
             }
             if (!signature.hasRestParameter && adjustedArgCount > signature.parameters.length) {
                 return false;
@@ -17640,7 +17657,7 @@ var ts;
                 var contextualParameterType = getTypeAtPosition(context, i);
                 assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
             }
-            if (signature.hasRestParameter && context.hasRestParameter && signature.parameters.length >= context.parameters.length) {
+            if (signature.hasRestParameter && isRestParameterIndex(context, signature.parameters.length - 1)) {
                 var parameter = ts.lastOrUndefined(signature.parameters);
                 var contextualParameterType = getTypeOfSymbol(ts.lastOrUndefined(context.parameters));
                 assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
@@ -17651,7 +17668,9 @@ var ts;
                 for (var _i = 0, _a = node.name.elements; _i < _a.length; _i++) {
                     var element = _a[_i];
                     if (element.kind !== 187) {
-                        getSymbolLinks(getSymbolOfNode(element)).type = getTypeForBindingElement(element);
+                        if (element.name.kind === 69) {
+                            getSymbolLinks(getSymbolOfNode(element)).type = getTypeForBindingElement(element);
+                        }
                         assignBindingElementTypes(element);
                     }
                 }
@@ -30506,10 +30525,6 @@ var ts;
                                 var start_2 = ts.getTokenPosOfNode(file.imports[i], file);
                                 fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_2, file.imports[i].end - start_2, ts.Diagnostics.Exported_external_package_typings_file_0_is_not_a_module_Please_contact_the_package_author_to_update_the_package_definition, importedFile.fileName));
                             }
-                            else if (!ts.fileExtensionIs(importedFile.fileName, ".d.ts")) {
-                                var start_3 = ts.getTokenPosOfNode(file.imports[i], file);
-                                fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_3, file.imports[i].end - start_3, ts.Diagnostics.Exported_external_package_typings_can_only_be_in_d_ts_files_Please_contact_the_package_author_to_update_the_package_definition));
-                            }
                             else if (importedFile.referencedFiles.length) {
                                 var firstRef = importedFile.referencedFiles[0];
                                 fileProcessingDiagnostics.add(ts.createFileDiagnostic(importedFile, firstRef.pos, firstRef.end - firstRef.pos, ts.Diagnostics.Exported_external_package_typings_file_cannot_contain_tripleslash_references_Please_contact_the_package_author_to_update_the_package_definition));
diff --git a/lib/tsserver.js b/lib/tsserver.js
index c0ac69112b7..1b1d3b06053 100644
--- a/lib/tsserver.js
+++ b/lib/tsserver.js
@@ -1534,7 +1534,6 @@ var ts;
         Merged_declaration_0_cannot_include_a_default_export_declaration_Consider_adding_a_separate_export_default_0_declaration_instead: { code: 2652, category: ts.DiagnosticCategory.Error, key: "Merged declaration '{0}' cannot include a default export declaration. Consider adding a separate 'export default {0}' declaration instead." },
         Non_abstract_class_expression_does_not_implement_inherited_abstract_member_0_from_class_1: { code: 2653, category: ts.DiagnosticCategory.Error, key: "Non-abstract class expression does not implement inherited abstract member '{0}' from class '{1}'." },
         Exported_external_package_typings_file_cannot_contain_tripleslash_references_Please_contact_the_package_author_to_update_the_package_definition: { code: 2654, category: ts.DiagnosticCategory.Error, key: "Exported external package typings file cannot contain tripleslash references. Please contact the package author to update the package definition." },
-        Exported_external_package_typings_can_only_be_in_d_ts_files_Please_contact_the_package_author_to_update_the_package_definition: { code: 2655, category: ts.DiagnosticCategory.Error, key: "Exported external package typings can only be in '.d.ts' files. Please contact the package author to update the package definition." },
         Exported_external_package_typings_file_0_is_not_a_module_Please_contact_the_package_author_to_update_the_package_definition: { code: 2656, category: ts.DiagnosticCategory.Error, key: "Exported external package typings file '{0}' is not a module. Please contact the package author to update the package definition." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: ts.DiagnosticCategory.Error, key: "Import declaration '{0}' is using private name '{1}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: { code: 4002, category: ts.DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
@@ -13094,22 +13093,27 @@ var ts;
             }
             return type.resolvedBaseConstructorType;
         }
+        function hasClassBaseType(type) {
+            return !!ts.forEach(getBaseTypes(type), function (t) { return !!(t.symbol.flags & 32); });
+        }
         function getBaseTypes(type) {
+            var isClass = type.symbol.flags & 32;
+            var isInterface = type.symbol.flags & 64;
             if (!type.resolvedBaseTypes) {
-                if (type.symbol.flags & 32) {
+                if (!isClass && !isInterface) {
+                    ts.Debug.fail("type must be class or interface");
+                }
+                if (isClass) {
                     resolveBaseTypesOfClass(type);
                 }
-                else if (type.symbol.flags & 64) {
+                if (isInterface) {
                     resolveBaseTypesOfInterface(type);
                 }
-                else {
-                    ts.Debug.fail("type must be class or interface");
-                }
             }
             return type.resolvedBaseTypes;
         }
         function resolveBaseTypesOfClass(type) {
-            type.resolvedBaseTypes = emptyArray;
+            type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray;
             var baseContructorType = getBaseConstructorTypeOfClass(type);
             if (!(baseContructorType.flags & 80896)) {
                 return;
@@ -13138,10 +13142,15 @@ var ts;
                 error(type.symbol.valueDeclaration, ts.Diagnostics.Type_0_recursively_references_itself_as_a_base_type, typeToString(type, undefined, 1));
                 return;
             }
-            type.resolvedBaseTypes = [baseType];
+            if (type.resolvedBaseTypes === emptyArray) {
+                type.resolvedBaseTypes = [baseType];
+            }
+            else {
+                type.resolvedBaseTypes.push(baseType);
+            }
         }
         function resolveBaseTypesOfInterface(type) {
-            type.resolvedBaseTypes = [];
+            type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray;
             for (var _i = 0, _a = type.symbol.declarations; _i < _a.length; _i++) {
                 var declaration = _a[_i];
                 if (declaration.kind === 215 && ts.getInterfaceBaseTypeNodes(declaration)) {
@@ -13151,7 +13160,12 @@ var ts;
                         if (baseType !== unknownType) {
                             if (getTargetType(baseType).flags & (1024 | 2048)) {
                                 if (type !== baseType && !hasBaseType(baseType, type)) {
-                                    type.resolvedBaseTypes.push(baseType);
+                                    if (type.resolvedBaseTypes === emptyArray) {
+                                        type.resolvedBaseTypes = [baseType];
+                                    }
+                                    else {
+                                        type.resolvedBaseTypes.push(baseType);
+                                    }
                                 }
                                 else {
                                     error(declaration, ts.Diagnostics.Type_0_recursively_references_itself_as_a_base_type, typeToString(type, undefined, 1));
@@ -13449,7 +13463,7 @@ var ts;
             return createSignature(sig.declaration, sig.typeParameters, sig.parameters, sig.resolvedReturnType, sig.typePredicate, sig.minArgumentCount, sig.hasRestParameter, sig.hasStringLiterals);
         }
         function getDefaultConstructSignatures(classType) {
-            if (!getBaseTypes(classType).length) {
+            if (!hasClassBaseType(classType)) {
                 return [createSignature(undefined, classType.localTypeParameters, emptyArray, classType, undefined, 0, false, false)];
             }
             var baseConstructorType = getBaseConstructorTypeOfClass(classType);
@@ -15430,11 +15444,10 @@ var ts;
             }
             source = getErasedSignature(source);
             target = getErasedSignature(target);
-            var sourceLen = source.parameters.length;
             var targetLen = target.parameters.length;
             for (var i = 0; i < targetLen; i++) {
-                var s = source.hasRestParameter && i === sourceLen - 1 ? getRestTypeOfSignature(source) : getTypeOfSymbol(source.parameters[i]);
-                var t = target.hasRestParameter && i === targetLen - 1 ? getRestTypeOfSignature(target) : getTypeOfSymbol(target.parameters[i]);
+                var s = isRestParameterIndex(source, i) ? getRestTypeOfSignature(source) : getTypeOfSymbol(source.parameters[i]);
+                var t = isRestParameterIndex(target, i) ? getRestTypeOfSignature(target) : getTypeOfSymbol(target.parameters[i]);
                 var related = compareTypes(s, t);
                 if (!related) {
                     return 0;
@@ -15446,6 +15459,9 @@ var ts;
             }
             return result;
         }
+        function isRestParameterIndex(signature, parameterIndex) {
+            return signature.hasRestParameter && parameterIndex >= signature.parameters.length - 1;
+        }
         function isSupertypeOfEach(candidate, types) {
             for (var _i = 0; _i < types.length; _i++) {
                 var type = types[_i];
@@ -16384,8 +16400,9 @@ var ts;
                         if (indexOfParameter < len) {
                             return getTypeAtPosition(contextualSignature, indexOfParameter);
                         }
-                        if (indexOfParameter === (func.parameters.length - 1) &&
-                            funcHasRestParameters && contextualSignature.hasRestParameter && func.parameters.length >= contextualSignature.parameters.length) {
+                        if (funcHasRestParameters &&
+                            indexOfParameter === (func.parameters.length - 1) &&
+                            isRestParameterIndex(contextualSignature, func.parameters.length - 1)) {
                             return getTypeOfSymbol(ts.lastOrUndefined(contextualSignature.parameters));
                         }
                     }
@@ -17505,7 +17522,7 @@ var ts;
                 return false;
             }
             if (spreadArgIndex >= 0) {
-                return signature.hasRestParameter && spreadArgIndex >= signature.parameters.length - 1;
+                return isRestParameterIndex(signature, spreadArgIndex);
             }
             if (!signature.hasRestParameter && adjustedArgCount > signature.parameters.length) {
                 return false;
@@ -18103,7 +18120,7 @@ var ts;
                 var contextualParameterType = getTypeAtPosition(context, i);
                 assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
             }
-            if (signature.hasRestParameter && context.hasRestParameter && signature.parameters.length >= context.parameters.length) {
+            if (signature.hasRestParameter && isRestParameterIndex(context, signature.parameters.length - 1)) {
                 var parameter = ts.lastOrUndefined(signature.parameters);
                 var contextualParameterType = getTypeOfSymbol(ts.lastOrUndefined(context.parameters));
                 assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
@@ -18114,7 +18131,9 @@ var ts;
                 for (var _i = 0, _a = node.name.elements; _i < _a.length; _i++) {
                     var element = _a[_i];
                     if (element.kind !== 187) {
-                        getSymbolLinks(getSymbolOfNode(element)).type = getTypeForBindingElement(element);
+                        if (element.name.kind === 69) {
+                            getSymbolLinks(getSymbolOfNode(element)).type = getTypeForBindingElement(element);
+                        }
                         assignBindingElementTypes(element);
                     }
                 }
@@ -30969,10 +30988,6 @@ var ts;
                                 var start_2 = ts.getTokenPosOfNode(file.imports[i], file);
                                 fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_2, file.imports[i].end - start_2, ts.Diagnostics.Exported_external_package_typings_file_0_is_not_a_module_Please_contact_the_package_author_to_update_the_package_definition, importedFile.fileName));
                             }
-                            else if (!ts.fileExtensionIs(importedFile.fileName, ".d.ts")) {
-                                var start_3 = ts.getTokenPosOfNode(file.imports[i], file);
-                                fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_3, file.imports[i].end - start_3, ts.Diagnostics.Exported_external_package_typings_can_only_be_in_d_ts_files_Please_contact_the_package_author_to_update_the_package_definition));
-                            }
                             else if (importedFile.referencedFiles.length) {
                                 var firstRef = importedFile.referencedFiles[0];
                                 fileProcessingDiagnostics.add(ts.createFileDiagnostic(importedFile, firstRef.pos, firstRef.end - firstRef.pos, ts.Diagnostics.Exported_external_package_typings_file_cannot_contain_tripleslash_references_Please_contact_the_package_author_to_update_the_package_definition));
@@ -37691,9 +37706,9 @@ var ts;
             log("getCompletionData: Get previous token 1: " + (new Date().getTime() - start));
             var contextToken = previousToken;
             if (contextToken && position <= contextToken.end && ts.isWord(contextToken.kind)) {
-                var start_4 = new Date().getTime();
+                var start_3 = new Date().getTime();
                 contextToken = ts.findPrecedingToken(contextToken.getFullStart(), sourceFile);
-                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_4));
+                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_3));
             }
             var node = currentToken;
             var isRightOfDot = false;
@@ -37915,9 +37930,9 @@ var ts;
                 if (contextToken.kind === 9
                     || contextToken.kind === 10
                     || ts.isTemplateLiteralKind(contextToken.kind)) {
-                    var start_5 = contextToken.getStart();
+                    var start_4 = contextToken.getStart();
                     var end = contextToken.getEnd();
-                    if (start_5 < position && position < end) {
+                    if (start_4 < position && position < end) {
                         return true;
                     }
                     if (position === end) {
@@ -43250,11 +43265,15 @@ var ts;
                                 if (info.isOpen) {
                                     if (this.openFileRoots.indexOf(info) >= 0) {
                                         this.openFileRoots = copyListRemovingItem(info, this.openFileRoots);
+                                        if (info.defaultProject && !info.defaultProject.isConfiguredProject()) {
+                                            this.removeProject(info.defaultProject);
+                                        }
                                     }
                                     if (this.openFilesReferenced.indexOf(info) >= 0) {
                                         this.openFilesReferenced = copyListRemovingItem(info, this.openFilesReferenced);
                                     }
                                     this.openFileRootsConfigured.push(info);
+                                    info.defaultProject = project;
                                 }
                             }
                             project.addRoot(info);
@@ -44275,6 +44294,33 @@ var ts;
             return new Logger(fileName, detailLevel);
         }
         var logger = createLoggerFromEnv();
+        var pending = [];
+        function queueMessage(s) {
+            pending.push(s);
+            if (pending.length === 1) {
+                drain();
+            }
+        }
+        function drain() {
+            ts.Debug.assert(pending.length > 0);
+            writeBuffer(new Buffer(pending[0], "utf8"), 0);
+        }
+        function writeBuffer(buffer, offset) {
+            var toWrite = buffer.length - offset;
+            fs.write(1, buffer, offset, toWrite, undefined, function (err, written, buffer) {
+                if (toWrite > written) {
+                    writeBuffer(buffer, offset + written);
+                }
+                else {
+                    ts.Debug.assert(pending.length > 0);
+                    pending.shift();
+                    if (pending.length > 0) {
+                        drain();
+                    }
+                }
+            });
+        }
+        ts.sys.write = function (s) { return queueMessage(s); };
         var ioSession = new IOSession(ts.sys, logger);
         process.on('uncaughtException', function (err) {
             ioSession.logError(err, "unknown");
diff --git a/lib/typescript.js b/lib/typescript.js
index 62e9c2a809b..d0f7741df2c 100644
--- a/lib/typescript.js
+++ b/lib/typescript.js
@@ -2449,7 +2449,6 @@ var ts;
         Merged_declaration_0_cannot_include_a_default_export_declaration_Consider_adding_a_separate_export_default_0_declaration_instead: { code: 2652, category: ts.DiagnosticCategory.Error, key: "Merged declaration '{0}' cannot include a default export declaration. Consider adding a separate 'export default {0}' declaration instead." },
         Non_abstract_class_expression_does_not_implement_inherited_abstract_member_0_from_class_1: { code: 2653, category: ts.DiagnosticCategory.Error, key: "Non-abstract class expression does not implement inherited abstract member '{0}' from class '{1}'." },
         Exported_external_package_typings_file_cannot_contain_tripleslash_references_Please_contact_the_package_author_to_update_the_package_definition: { code: 2654, category: ts.DiagnosticCategory.Error, key: "Exported external package typings file cannot contain tripleslash references. Please contact the package author to update the package definition." },
-        Exported_external_package_typings_can_only_be_in_d_ts_files_Please_contact_the_package_author_to_update_the_package_definition: { code: 2655, category: ts.DiagnosticCategory.Error, key: "Exported external package typings can only be in '.d.ts' files. Please contact the package author to update the package definition." },
         Exported_external_package_typings_file_0_is_not_a_module_Please_contact_the_package_author_to_update_the_package_definition: { code: 2656, category: ts.DiagnosticCategory.Error, key: "Exported external package typings file '{0}' is not a module. Please contact the package author to update the package definition." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: ts.DiagnosticCategory.Error, key: "Import declaration '{0}' is using private name '{1}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: { code: 4002, category: ts.DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
@@ -15810,22 +15809,27 @@ var ts;
             }
             return type.resolvedBaseConstructorType;
         }
+        function hasClassBaseType(type) {
+            return !!ts.forEach(getBaseTypes(type), function (t) { return !!(t.symbol.flags & 32 /* Class */); });
+        }
         function getBaseTypes(type) {
+            var isClass = type.symbol.flags & 32 /* Class */;
+            var isInterface = type.symbol.flags & 64 /* Interface */;
             if (!type.resolvedBaseTypes) {
-                if (type.symbol.flags & 32 /* Class */) {
+                if (!isClass && !isInterface) {
+                    ts.Debug.fail("type must be class or interface");
+                }
+                if (isClass) {
                     resolveBaseTypesOfClass(type);
                 }
-                else if (type.symbol.flags & 64 /* Interface */) {
+                if (isInterface) {
                     resolveBaseTypesOfInterface(type);
                 }
-                else {
-                    ts.Debug.fail("type must be class or interface");
-                }
             }
             return type.resolvedBaseTypes;
         }
         function resolveBaseTypesOfClass(type) {
-            type.resolvedBaseTypes = emptyArray;
+            type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray;
             var baseContructorType = getBaseConstructorTypeOfClass(type);
             if (!(baseContructorType.flags & 80896 /* ObjectType */)) {
                 return;
@@ -15860,10 +15864,15 @@ var ts;
                 error(type.symbol.valueDeclaration, ts.Diagnostics.Type_0_recursively_references_itself_as_a_base_type, typeToString(type, /*enclosingDeclaration*/ undefined, 1 /* WriteArrayAsGenericType */));
                 return;
             }
-            type.resolvedBaseTypes = [baseType];
+            if (type.resolvedBaseTypes === emptyArray) {
+                type.resolvedBaseTypes = [baseType];
+            }
+            else {
+                type.resolvedBaseTypes.push(baseType);
+            }
         }
         function resolveBaseTypesOfInterface(type) {
-            type.resolvedBaseTypes = [];
+            type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray;
             for (var _i = 0, _a = type.symbol.declarations; _i < _a.length; _i++) {
                 var declaration = _a[_i];
                 if (declaration.kind === 215 /* InterfaceDeclaration */ && ts.getInterfaceBaseTypeNodes(declaration)) {
@@ -15873,7 +15882,12 @@ var ts;
                         if (baseType !== unknownType) {
                             if (getTargetType(baseType).flags & (1024 /* Class */ | 2048 /* Interface */)) {
                                 if (type !== baseType && !hasBaseType(baseType, type)) {
-                                    type.resolvedBaseTypes.push(baseType);
+                                    if (type.resolvedBaseTypes === emptyArray) {
+                                        type.resolvedBaseTypes = [baseType];
+                                    }
+                                    else {
+                                        type.resolvedBaseTypes.push(baseType);
+                                    }
                                 }
                                 else {
                                     error(declaration, ts.Diagnostics.Type_0_recursively_references_itself_as_a_base_type, typeToString(type, /*enclosingDeclaration*/ undefined, 1 /* WriteArrayAsGenericType */));
@@ -16198,7 +16212,7 @@ var ts;
             return createSignature(sig.declaration, sig.typeParameters, sig.parameters, sig.resolvedReturnType, sig.typePredicate, sig.minArgumentCount, sig.hasRestParameter, sig.hasStringLiterals);
         }
         function getDefaultConstructSignatures(classType) {
-            if (!getBaseTypes(classType).length) {
+            if (!hasClassBaseType(classType)) {
                 return [createSignature(undefined, classType.localTypeParameters, emptyArray, classType, undefined, 0, false, false)];
             }
             var baseConstructorType = getBaseConstructorTypeOfClass(classType);
@@ -18385,11 +18399,10 @@ var ts;
             // M and N (the signatures) are instantiated using type Any as the type argument for all type parameters declared by M and N
             source = getErasedSignature(source);
             target = getErasedSignature(target);
-            var sourceLen = source.parameters.length;
             var targetLen = target.parameters.length;
             for (var i = 0; i < targetLen; i++) {
-                var s = source.hasRestParameter && i === sourceLen - 1 ? getRestTypeOfSignature(source) : getTypeOfSymbol(source.parameters[i]);
-                var t = target.hasRestParameter && i === targetLen - 1 ? getRestTypeOfSignature(target) : getTypeOfSymbol(target.parameters[i]);
+                var s = isRestParameterIndex(source, i) ? getRestTypeOfSignature(source) : getTypeOfSymbol(source.parameters[i]);
+                var t = isRestParameterIndex(target, i) ? getRestTypeOfSignature(target) : getTypeOfSymbol(target.parameters[i]);
                 var related = compareTypes(s, t);
                 if (!related) {
                     return 0 /* False */;
@@ -18401,6 +18414,9 @@ var ts;
             }
             return result;
         }
+        function isRestParameterIndex(signature, parameterIndex) {
+            return signature.hasRestParameter && parameterIndex >= signature.parameters.length - 1;
+        }
         function isSupertypeOfEach(candidate, types) {
             for (var _i = 0; _i < types.length; _i++) {
                 var type = types[_i];
@@ -19470,8 +19486,9 @@ var ts;
                             return getTypeAtPosition(contextualSignature, indexOfParameter);
                         }
                         // If last parameter is contextually rest parameter get its type
-                        if (indexOfParameter === (func.parameters.length - 1) &&
-                            funcHasRestParameters && contextualSignature.hasRestParameter && func.parameters.length >= contextualSignature.parameters.length) {
+                        if (funcHasRestParameters &&
+                            indexOfParameter === (func.parameters.length - 1) &&
+                            isRestParameterIndex(contextualSignature, func.parameters.length - 1)) {
                             return getTypeOfSymbol(ts.lastOrUndefined(contextualSignature.parameters));
                         }
                     }
@@ -20895,7 +20912,7 @@ var ts;
             // If spread arguments are present, check that they correspond to a rest parameter. If so, no
             // further checking is necessary.
             if (spreadArgIndex >= 0) {
-                return signature.hasRestParameter && spreadArgIndex >= signature.parameters.length - 1;
+                return isRestParameterIndex(signature, spreadArgIndex);
             }
             // Too many arguments implies incorrect arity.
             if (!signature.hasRestParameter && adjustedArgCount > signature.parameters.length) {
@@ -21768,7 +21785,7 @@ var ts;
                 var contextualParameterType = getTypeAtPosition(context, i);
                 assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
             }
-            if (signature.hasRestParameter && context.hasRestParameter && signature.parameters.length >= context.parameters.length) {
+            if (signature.hasRestParameter && isRestParameterIndex(context, signature.parameters.length - 1)) {
                 var parameter = ts.lastOrUndefined(signature.parameters);
                 var contextualParameterType = getTypeOfSymbol(ts.lastOrUndefined(context.parameters));
                 assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
@@ -21781,7 +21798,9 @@ var ts;
                 for (var _i = 0, _a = node.name.elements; _i < _a.length; _i++) {
                     var element = _a[_i];
                     if (element.kind !== 187 /* OmittedExpression */) {
-                        getSymbolLinks(getSymbolOfNode(element)).type = getTypeForBindingElement(element);
+                        if (element.name.kind === 69 /* Identifier */) {
+                            getSymbolLinks(getSymbolOfNode(element)).type = getTypeForBindingElement(element);
+                        }
                         assignBindingElementTypes(element);
                     }
                 }
@@ -36684,10 +36703,6 @@ var ts;
                                 var start_2 = ts.getTokenPosOfNode(file.imports[i], file);
                                 fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_2, file.imports[i].end - start_2, ts.Diagnostics.Exported_external_package_typings_file_0_is_not_a_module_Please_contact_the_package_author_to_update_the_package_definition, importedFile.fileName));
                             }
-                            else if (!ts.fileExtensionIs(importedFile.fileName, ".d.ts")) {
-                                var start_3 = ts.getTokenPosOfNode(file.imports[i], file);
-                                fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_3, file.imports[i].end - start_3, ts.Diagnostics.Exported_external_package_typings_can_only_be_in_d_ts_files_Please_contact_the_package_author_to_update_the_package_definition));
-                            }
                             else if (importedFile.referencedFiles.length) {
                                 var firstRef = importedFile.referencedFiles[0];
                                 fileProcessingDiagnostics.add(ts.createFileDiagnostic(importedFile, firstRef.pos, firstRef.end - firstRef.pos, ts.Diagnostics.Exported_external_package_typings_file_cannot_contain_tripleslash_references_Please_contact_the_package_author_to_update_the_package_definition));
@@ -44885,9 +44900,9 @@ var ts;
             // Check if the caret is at the end of an identifier; this is a partial identifier that we want to complete: e.g. a.toS|
             // Skip this partial identifier and adjust the contextToken to the token that precedes it.
             if (contextToken && position <= contextToken.end && ts.isWord(contextToken.kind)) {
-                var start_4 = new Date().getTime();
+                var start_3 = new Date().getTime();
                 contextToken = ts.findPrecedingToken(contextToken.getFullStart(), sourceFile);
-                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_4));
+                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_3));
             }
             // Find the node where completion is requested on.
             // Also determine whether we are trying to complete with members of that node
@@ -45162,13 +45177,13 @@ var ts;
                 if (contextToken.kind === 9 /* StringLiteral */
                     || contextToken.kind === 10 /* RegularExpressionLiteral */
                     || ts.isTemplateLiteralKind(contextToken.kind)) {
-                    var start_5 = contextToken.getStart();
+                    var start_4 = contextToken.getStart();
                     var end = contextToken.getEnd();
                     // To be "in" one of these literals, the position has to be:
                     //   1. entirely within the token text.
                     //   2. at the end position of an unterminated token.
                     //   3. at the end of a regular expression (due to trailing flags like '/foo/g').
-                    if (start_5 < position && position < end) {
+                    if (start_4 < position && position < end) {
                         return true;
                     }
                     if (position === end) {
diff --git a/lib/typescriptServices.js b/lib/typescriptServices.js
index 62e9c2a809b..d0f7741df2c 100644
--- a/lib/typescriptServices.js
+++ b/lib/typescriptServices.js
@@ -2449,7 +2449,6 @@ var ts;
         Merged_declaration_0_cannot_include_a_default_export_declaration_Consider_adding_a_separate_export_default_0_declaration_instead: { code: 2652, category: ts.DiagnosticCategory.Error, key: "Merged declaration '{0}' cannot include a default export declaration. Consider adding a separate 'export default {0}' declaration instead." },
         Non_abstract_class_expression_does_not_implement_inherited_abstract_member_0_from_class_1: { code: 2653, category: ts.DiagnosticCategory.Error, key: "Non-abstract class expression does not implement inherited abstract member '{0}' from class '{1}'." },
         Exported_external_package_typings_file_cannot_contain_tripleslash_references_Please_contact_the_package_author_to_update_the_package_definition: { code: 2654, category: ts.DiagnosticCategory.Error, key: "Exported external package typings file cannot contain tripleslash references. Please contact the package author to update the package definition." },
-        Exported_external_package_typings_can_only_be_in_d_ts_files_Please_contact_the_package_author_to_update_the_package_definition: { code: 2655, category: ts.DiagnosticCategory.Error, key: "Exported external package typings can only be in '.d.ts' files. Please contact the package author to update the package definition." },
         Exported_external_package_typings_file_0_is_not_a_module_Please_contact_the_package_author_to_update_the_package_definition: { code: 2656, category: ts.DiagnosticCategory.Error, key: "Exported external package typings file '{0}' is not a module. Please contact the package author to update the package definition." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: ts.DiagnosticCategory.Error, key: "Import declaration '{0}' is using private name '{1}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: { code: 4002, category: ts.DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
@@ -15810,22 +15809,27 @@ var ts;
             }
             return type.resolvedBaseConstructorType;
         }
+        function hasClassBaseType(type) {
+            return !!ts.forEach(getBaseTypes(type), function (t) { return !!(t.symbol.flags & 32 /* Class */); });
+        }
         function getBaseTypes(type) {
+            var isClass = type.symbol.flags & 32 /* Class */;
+            var isInterface = type.symbol.flags & 64 /* Interface */;
             if (!type.resolvedBaseTypes) {
-                if (type.symbol.flags & 32 /* Class */) {
+                if (!isClass && !isInterface) {
+                    ts.Debug.fail("type must be class or interface");
+                }
+                if (isClass) {
                     resolveBaseTypesOfClass(type);
                 }
-                else if (type.symbol.flags & 64 /* Interface */) {
+                if (isInterface) {
                     resolveBaseTypesOfInterface(type);
                 }
-                else {
-                    ts.Debug.fail("type must be class or interface");
-                }
             }
             return type.resolvedBaseTypes;
         }
         function resolveBaseTypesOfClass(type) {
-            type.resolvedBaseTypes = emptyArray;
+            type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray;
             var baseContructorType = getBaseConstructorTypeOfClass(type);
             if (!(baseContructorType.flags & 80896 /* ObjectType */)) {
                 return;
@@ -15860,10 +15864,15 @@ var ts;
                 error(type.symbol.valueDeclaration, ts.Diagnostics.Type_0_recursively_references_itself_as_a_base_type, typeToString(type, /*enclosingDeclaration*/ undefined, 1 /* WriteArrayAsGenericType */));
                 return;
             }
-            type.resolvedBaseTypes = [baseType];
+            if (type.resolvedBaseTypes === emptyArray) {
+                type.resolvedBaseTypes = [baseType];
+            }
+            else {
+                type.resolvedBaseTypes.push(baseType);
+            }
         }
         function resolveBaseTypesOfInterface(type) {
-            type.resolvedBaseTypes = [];
+            type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray;
             for (var _i = 0, _a = type.symbol.declarations; _i < _a.length; _i++) {
                 var declaration = _a[_i];
                 if (declaration.kind === 215 /* InterfaceDeclaration */ && ts.getInterfaceBaseTypeNodes(declaration)) {
@@ -15873,7 +15882,12 @@ var ts;
                         if (baseType !== unknownType) {
                             if (getTargetType(baseType).flags & (1024 /* Class */ | 2048 /* Interface */)) {
                                 if (type !== baseType && !hasBaseType(baseType, type)) {
-                                    type.resolvedBaseTypes.push(baseType);
+                                    if (type.resolvedBaseTypes === emptyArray) {
+                                        type.resolvedBaseTypes = [baseType];
+                                    }
+                                    else {
+                                        type.resolvedBaseTypes.push(baseType);
+                                    }
                                 }
                                 else {
                                     error(declaration, ts.Diagnostics.Type_0_recursively_references_itself_as_a_base_type, typeToString(type, /*enclosingDeclaration*/ undefined, 1 /* WriteArrayAsGenericType */));
@@ -16198,7 +16212,7 @@ var ts;
             return createSignature(sig.declaration, sig.typeParameters, sig.parameters, sig.resolvedReturnType, sig.typePredicate, sig.minArgumentCount, sig.hasRestParameter, sig.hasStringLiterals);
         }
         function getDefaultConstructSignatures(classType) {
-            if (!getBaseTypes(classType).length) {
+            if (!hasClassBaseType(classType)) {
                 return [createSignature(undefined, classType.localTypeParameters, emptyArray, classType, undefined, 0, false, false)];
             }
             var baseConstructorType = getBaseConstructorTypeOfClass(classType);
@@ -18385,11 +18399,10 @@ var ts;
             // M and N (the signatures) are instantiated using type Any as the type argument for all type parameters declared by M and N
             source = getErasedSignature(source);
             target = getErasedSignature(target);
-            var sourceLen = source.parameters.length;
             var targetLen = target.parameters.length;
             for (var i = 0; i < targetLen; i++) {
-                var s = source.hasRestParameter && i === sourceLen - 1 ? getRestTypeOfSignature(source) : getTypeOfSymbol(source.parameters[i]);
-                var t = target.hasRestParameter && i === targetLen - 1 ? getRestTypeOfSignature(target) : getTypeOfSymbol(target.parameters[i]);
+                var s = isRestParameterIndex(source, i) ? getRestTypeOfSignature(source) : getTypeOfSymbol(source.parameters[i]);
+                var t = isRestParameterIndex(target, i) ? getRestTypeOfSignature(target) : getTypeOfSymbol(target.parameters[i]);
                 var related = compareTypes(s, t);
                 if (!related) {
                     return 0 /* False */;
@@ -18401,6 +18414,9 @@ var ts;
             }
             return result;
         }
+        function isRestParameterIndex(signature, parameterIndex) {
+            return signature.hasRestParameter && parameterIndex >= signature.parameters.length - 1;
+        }
         function isSupertypeOfEach(candidate, types) {
             for (var _i = 0; _i < types.length; _i++) {
                 var type = types[_i];
@@ -19470,8 +19486,9 @@ var ts;
                             return getTypeAtPosition(contextualSignature, indexOfParameter);
                         }
                         // If last parameter is contextually rest parameter get its type
-                        if (indexOfParameter === (func.parameters.length - 1) &&
-                            funcHasRestParameters && contextualSignature.hasRestParameter && func.parameters.length >= contextualSignature.parameters.length) {
+                        if (funcHasRestParameters &&
+                            indexOfParameter === (func.parameters.length - 1) &&
+                            isRestParameterIndex(contextualSignature, func.parameters.length - 1)) {
                             return getTypeOfSymbol(ts.lastOrUndefined(contextualSignature.parameters));
                         }
                     }
@@ -20895,7 +20912,7 @@ var ts;
             // If spread arguments are present, check that they correspond to a rest parameter. If so, no
             // further checking is necessary.
             if (spreadArgIndex >= 0) {
-                return signature.hasRestParameter && spreadArgIndex >= signature.parameters.length - 1;
+                return isRestParameterIndex(signature, spreadArgIndex);
             }
             // Too many arguments implies incorrect arity.
             if (!signature.hasRestParameter && adjustedArgCount > signature.parameters.length) {
@@ -21768,7 +21785,7 @@ var ts;
                 var contextualParameterType = getTypeAtPosition(context, i);
                 assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
             }
-            if (signature.hasRestParameter && context.hasRestParameter && signature.parameters.length >= context.parameters.length) {
+            if (signature.hasRestParameter && isRestParameterIndex(context, signature.parameters.length - 1)) {
                 var parameter = ts.lastOrUndefined(signature.parameters);
                 var contextualParameterType = getTypeOfSymbol(ts.lastOrUndefined(context.parameters));
                 assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
@@ -21781,7 +21798,9 @@ var ts;
                 for (var _i = 0, _a = node.name.elements; _i < _a.length; _i++) {
                     var element = _a[_i];
                     if (element.kind !== 187 /* OmittedExpression */) {
-                        getSymbolLinks(getSymbolOfNode(element)).type = getTypeForBindingElement(element);
+                        if (element.name.kind === 69 /* Identifier */) {
+                            getSymbolLinks(getSymbolOfNode(element)).type = getTypeForBindingElement(element);
+                        }
                         assignBindingElementTypes(element);
                     }
                 }
@@ -36684,10 +36703,6 @@ var ts;
                                 var start_2 = ts.getTokenPosOfNode(file.imports[i], file);
                                 fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_2, file.imports[i].end - start_2, ts.Diagnostics.Exported_external_package_typings_file_0_is_not_a_module_Please_contact_the_package_author_to_update_the_package_definition, importedFile.fileName));
                             }
-                            else if (!ts.fileExtensionIs(importedFile.fileName, ".d.ts")) {
-                                var start_3 = ts.getTokenPosOfNode(file.imports[i], file);
-                                fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_3, file.imports[i].end - start_3, ts.Diagnostics.Exported_external_package_typings_can_only_be_in_d_ts_files_Please_contact_the_package_author_to_update_the_package_definition));
-                            }
                             else if (importedFile.referencedFiles.length) {
                                 var firstRef = importedFile.referencedFiles[0];
                                 fileProcessingDiagnostics.add(ts.createFileDiagnostic(importedFile, firstRef.pos, firstRef.end - firstRef.pos, ts.Diagnostics.Exported_external_package_typings_file_cannot_contain_tripleslash_references_Please_contact_the_package_author_to_update_the_package_definition));
@@ -44885,9 +44900,9 @@ var ts;
             // Check if the caret is at the end of an identifier; this is a partial identifier that we want to complete: e.g. a.toS|
             // Skip this partial identifier and adjust the contextToken to the token that precedes it.
             if (contextToken && position <= contextToken.end && ts.isWord(contextToken.kind)) {
-                var start_4 = new Date().getTime();
+                var start_3 = new Date().getTime();
                 contextToken = ts.findPrecedingToken(contextToken.getFullStart(), sourceFile);
-                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_4));
+                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_3));
             }
             // Find the node where completion is requested on.
             // Also determine whether we are trying to complete with members of that node
@@ -45162,13 +45177,13 @@ var ts;
                 if (contextToken.kind === 9 /* StringLiteral */
                     || contextToken.kind === 10 /* RegularExpressionLiteral */
                     || ts.isTemplateLiteralKind(contextToken.kind)) {
-                    var start_5 = contextToken.getStart();
+                    var start_4 = contextToken.getStart();
                     var end = contextToken.getEnd();
                     // To be "in" one of these literals, the position has to be:
                     //   1. entirely within the token text.
                     //   2. at the end position of an unterminated token.
                     //   3. at the end of a regular expression (due to trailing flags like '/foo/g').
-                    if (start_5 < position && position < end) {
+                    if (start_4 < position && position < end) {
                         return true;
                     }
                     if (position === end) {