diff --git a/lib/lib.d.ts b/lib/lib.d.ts
index 6bded7a1135..15745c5d533 100644
--- a/lib/lib.d.ts
+++ b/lib/lib.d.ts
@@ -965,38 +965,22 @@ interface JSON {
       * If a member contains nested objects, the nested objects are transformed before the parent object is.
       */
     parse(text: string, reviver?: (key: any, value: any) => any): any;
-    /**
-      * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
-      * @param value A JavaScript value, usually an object or array, to be converted.
-      */
-    stringify(value: any): string;
-    /**
-      * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
-      * @param value A JavaScript value, usually an object or array, to be converted.
-      * @param replacer A function that transforms the results.
-      */
-    stringify(value: any, replacer: (key: string, value: any) => any): string;
-    /**
-      * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
-      * @param value A JavaScript value, usually an object or array, to be converted.
-      * @param replacer Array that transforms the results.
-      */
-    stringify(value: any, replacer: any[]): string;
     /**
       * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
       * @param value A JavaScript value, usually an object or array, to be converted.
       * @param replacer A function that transforms the results.
       * @param space Adds indentation, white space, and line break characters to the return-value JSON text to make it easier to read.
       */
-    stringify(value: any, replacer: (key: string, value: any) => any, space: string | number): string;
+    stringify(value: any, replacer?: (key: string, value: any) => any, space?: string | number): string;
     /**
       * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
       * @param value A JavaScript value, usually an object or array, to be converted.
-      * @param replacer Array that transforms the results.
+      * @param replacer An array of strings and numbers that acts as a white list for selecting the object properties that will be stringified.
       * @param space Adds indentation, white space, and line break characters to the return-value JSON text to make it easier to read.
       */
-    stringify(value: any, replacer: any[], space: string | number): string;
+    stringify(value: any, replacer?: (number | string)[] | null, space?: string | number): string;
 }
+
 /**
   * An intrinsic object that provides functions to convert JavaScript values to and from the JavaScript Object Notation (JSON) format.
   */
diff --git a/lib/lib.es5.d.ts b/lib/lib.es5.d.ts
index 3a0f73f3cc7..e4e0334e0cb 100644
--- a/lib/lib.es5.d.ts
+++ b/lib/lib.es5.d.ts
@@ -965,38 +965,22 @@ interface JSON {
       * If a member contains nested objects, the nested objects are transformed before the parent object is.
       */
     parse(text: string, reviver?: (key: any, value: any) => any): any;
-    /**
-      * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
-      * @param value A JavaScript value, usually an object or array, to be converted.
-      */
-    stringify(value: any): string;
-    /**
-      * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
-      * @param value A JavaScript value, usually an object or array, to be converted.
-      * @param replacer A function that transforms the results.
-      */
-    stringify(value: any, replacer: (key: string, value: any) => any): string;
-    /**
-      * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
-      * @param value A JavaScript value, usually an object or array, to be converted.
-      * @param replacer Array that transforms the results.
-      */
-    stringify(value: any, replacer: any[]): string;
     /**
       * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
       * @param value A JavaScript value, usually an object or array, to be converted.
       * @param replacer A function that transforms the results.
       * @param space Adds indentation, white space, and line break characters to the return-value JSON text to make it easier to read.
       */
-    stringify(value: any, replacer: (key: string, value: any) => any, space: string | number): string;
+    stringify(value: any, replacer?: (key: string, value: any) => any, space?: string | number): string;
     /**
       * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
       * @param value A JavaScript value, usually an object or array, to be converted.
-      * @param replacer Array that transforms the results.
+      * @param replacer An array of strings and numbers that acts as a white list for selecting the object properties that will be stringified.
       * @param space Adds indentation, white space, and line break characters to the return-value JSON text to make it easier to read.
       */
-    stringify(value: any, replacer: any[], space: string | number): string;
+    stringify(value: any, replacer?: (number | string)[] | null, space?: string | number): string;
 }
+
 /**
   * An intrinsic object that provides functions to convert JavaScript values to and from the JavaScript Object Notation (JSON) format.
   */
diff --git a/lib/lib.es6.d.ts b/lib/lib.es6.d.ts
index 6ed743d739a..ae54e8e8570 100644
--- a/lib/lib.es6.d.ts
+++ b/lib/lib.es6.d.ts
@@ -965,38 +965,22 @@ interface JSON {
       * If a member contains nested objects, the nested objects are transformed before the parent object is.
       */
     parse(text: string, reviver?: (key: any, value: any) => any): any;
-    /**
-      * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
-      * @param value A JavaScript value, usually an object or array, to be converted.
-      */
-    stringify(value: any): string;
-    /**
-      * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
-      * @param value A JavaScript value, usually an object or array, to be converted.
-      * @param replacer A function that transforms the results.
-      */
-    stringify(value: any, replacer: (key: string, value: any) => any): string;
-    /**
-      * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
-      * @param value A JavaScript value, usually an object or array, to be converted.
-      * @param replacer Array that transforms the results.
-      */
-    stringify(value: any, replacer: any[]): string;
     /**
       * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
       * @param value A JavaScript value, usually an object or array, to be converted.
       * @param replacer A function that transforms the results.
       * @param space Adds indentation, white space, and line break characters to the return-value JSON text to make it easier to read.
       */
-    stringify(value: any, replacer: (key: string, value: any) => any, space: string | number): string;
+    stringify(value: any, replacer?: (key: string, value: any) => any, space?: string | number): string;
     /**
       * Converts a JavaScript value to a JavaScript Object Notation (JSON) string.
       * @param value A JavaScript value, usually an object or array, to be converted.
-      * @param replacer Array that transforms the results.
+      * @param replacer An array of strings and numbers that acts as a white list for selecting the object properties that will be stringified.
       * @param space Adds indentation, white space, and line break characters to the return-value JSON text to make it easier to read.
       */
-    stringify(value: any, replacer: any[], space: string | number): string;
+    stringify(value: any, replacer?: (number | string)[] | null, space?: string | number): string;
 }
+
 /**
   * An intrinsic object that provides functions to convert JavaScript values to and from the JavaScript Object Notation (JSON) format.
   */
diff --git a/lib/tsc.js b/lib/tsc.js
index 8dba7a921dc..00c758c0446 100644
--- a/lib/tsc.js
+++ b/lib/tsc.js
@@ -913,6 +913,10 @@ var ts;
                 }
                 return result.sort();
             }
+            function getDirectories(path) {
+                var folder = fso.GetFolder(path);
+                return getNames(folder.subfolders);
+            }
             function readDirectory(path, extension, exclude) {
                 var result = [];
                 exclude = ts.map(exclude, function (s) { return getCanonicalPath(ts.combinePaths(path, s)); });
@@ -967,6 +971,7 @@ var ts;
                 getCurrentDirectory: function () {
                     return new ActiveXObject("WScript.Shell").CurrentDirectory;
                 },
+                getDirectories: getDirectories,
                 readDirectory: readDirectory,
                 exit: function (exitCode) {
                     try {
@@ -1114,6 +1119,9 @@ var ts;
             function directoryExists(path) {
                 return fileSystemEntryExists(path, 1);
             }
+            function getDirectories(path) {
+                return ts.filter(_fs.readdirSync(path), function (p) { return fileSystemEntryExists(ts.combinePaths(path, p), 1); });
+            }
             function readDirectory(path, extension, exclude) {
                 var result = [];
                 exclude = ts.map(exclude, function (s) { return getCanonicalPath(ts.combinePaths(path, s)); });
@@ -1206,6 +1214,7 @@ var ts;
                 getCurrentDirectory: function () {
                     return process.cwd();
                 },
+                getDirectories: getDirectories,
                 readDirectory: readDirectory,
                 getModifiedTime: function (path) {
                     try {
@@ -1256,6 +1265,7 @@ var ts;
                 createDirectory: ChakraHost.createDirectory,
                 getExecutingFilePath: function () { return ChakraHost.executingFile; },
                 getCurrentDirectory: function () { return ChakraHost.currentDirectory; },
+                getDirectories: ChakraHost.getDirectories,
                 readDirectory: ChakraHost.readDirectory,
                 exit: ChakraHost.quit,
                 realpath: realpath
@@ -1389,7 +1399,7 @@ var ts;
         or_expected: { code: 1144, category: ts.DiagnosticCategory.Error, key: "or_expected_1144", message: "'{' or ';' expected." },
         Declaration_expected: { code: 1146, category: ts.DiagnosticCategory.Error, key: "Declaration_expected_1146", message: "Declaration expected." },
         Import_declarations_in_a_namespace_cannot_reference_a_module: { code: 1147, category: ts.DiagnosticCategory.Error, key: "Import_declarations_in_a_namespace_cannot_reference_a_module_1147", message: "Import declarations in a namespace cannot reference a module." },
-        Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file: { code: 1148, category: ts.DiagnosticCategory.Error, key: "Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting__1148", message: "Cannot compile modules unless the '--module' flag is provided with a valid module type. Consider setting the 'module' compiler option in a 'tsconfig.json' file." },
+        Cannot_use_imports_exports_or_module_augmentations_when_module_is_none: { code: 1148, category: ts.DiagnosticCategory.Error, key: "Cannot_use_imports_exports_or_module_augmentations_when_module_is_none_1148", message: "Cannot use imports, exports, or module augmentations when '--module' is 'none'." },
         File_name_0_differs_from_already_included_file_name_1_only_in_casing: { code: 1149, category: ts.DiagnosticCategory.Error, key: "File_name_0_differs_from_already_included_file_name_1_only_in_casing_1149", message: "File name '{0}' differs from already included file name '{1}' only in casing" },
         new_T_cannot_be_used_to_create_an_array_Use_new_Array_T_instead: { code: 1150, category: ts.DiagnosticCategory.Error, key: "new_T_cannot_be_used_to_create_an_array_Use_new_Array_T_instead_1150", message: "'new T[]' cannot be used to create an array. Use 'new Array<T>()' instead." },
         const_declarations_must_be_initialized: { code: 1155, category: ts.DiagnosticCategory.Error, key: "const_declarations_must_be_initialized_1155", message: "'const' declarations must be initialized" },
@@ -1759,6 +1769,8 @@ var ts;
         this_implicitly_has_type_any_because_it_does_not_have_a_type_annotation: { code: 2683, category: ts.DiagnosticCategory.Error, key: "this_implicitly_has_type_any_because_it_does_not_have_a_type_annotation_2683", message: "'this' implicitly has type 'any' because it does not have a type annotation." },
         The_this_context_of_type_0_is_not_assignable_to_method_s_this_of_type_1: { code: 2684, category: ts.DiagnosticCategory.Error, key: "The_this_context_of_type_0_is_not_assignable_to_method_s_this_of_type_1_2684", message: "The 'this' context of type '{0}' is not assignable to method's 'this' of type '{1}'." },
         The_this_types_of_each_signature_are_incompatible: { code: 2685, category: ts.DiagnosticCategory.Error, key: "The_this_types_of_each_signature_are_incompatible_2685", message: "The 'this' types of each signature are incompatible." },
+        Identifier_0_must_be_imported_from_a_module: { code: 2686, category: ts.DiagnosticCategory.Error, key: "Identifier_0_must_be_imported_from_a_module_2686", message: "Identifier '{0}' must be imported from a module" },
+        All_declarations_of_0_must_have_identical_modifiers: { code: 2687, category: ts.DiagnosticCategory.Error, key: "All_declarations_of_0_must_have_identical_modifiers_2687", message: "All declarations of '{0}' must have identical modifiers." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: ts.DiagnosticCategory.Error, key: "Import_declaration_0_is_using_private_name_1_4000", message: "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_4002", message: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
         Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1: { code: 4004, category: ts.DiagnosticCategory.Error, key: "Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1_4004", message: "Type parameter '{0}' of exported interface has or is using private name '{1}'." },
@@ -1852,7 +1864,7 @@ var ts;
         Option_paths_cannot_be_used_without_specifying_baseUrl_option: { code: 5060, category: ts.DiagnosticCategory.Error, key: "Option_paths_cannot_be_used_without_specifying_baseUrl_option_5060", message: "Option 'paths' cannot be used without specifying '--baseUrl' option." },
         Pattern_0_can_have_at_most_one_Asterisk_character: { code: 5061, category: ts.DiagnosticCategory.Error, key: "Pattern_0_can_have_at_most_one_Asterisk_character_5061", message: "Pattern '{0}' can have at most one '*' character" },
         Substitution_0_in_pattern_1_in_can_have_at_most_one_Asterisk_character: { code: 5062, category: ts.DiagnosticCategory.Error, key: "Substitution_0_in_pattern_1_in_can_have_at_most_one_Asterisk_character_5062", message: "Substitution '{0}' in pattern '{1}' in can have at most one '*' character" },
-        Substututions_for_pattern_0_should_be_an_array: { code: 5063, category: ts.DiagnosticCategory.Error, key: "Substututions_for_pattern_0_should_be_an_array_5063", message: "Substututions for pattern '{0}' should be an array." },
+        Substitutions_for_pattern_0_should_be_an_array: { code: 5063, category: ts.DiagnosticCategory.Error, key: "Substitutions_for_pattern_0_should_be_an_array_5063", message: "Substitutions for pattern '{0}' should be an array." },
         Substitution_0_for_pattern_1_has_incorrect_type_expected_string_got_2: { code: 5064, category: ts.DiagnosticCategory.Error, key: "Substitution_0_for_pattern_1_has_incorrect_type_expected_string_got_2_5064", message: "Substitution '{0}' for pattern '{1}' has incorrect type, expected 'string', got '{2}'." },
         Concatenate_and_emit_output_to_single_file: { code: 6001, category: ts.DiagnosticCategory.Message, key: "Concatenate_and_emit_output_to_single_file_6001", message: "Concatenate and emit output to single file." },
         Generates_corresponding_d_ts_file: { code: 6002, category: ts.DiagnosticCategory.Message, key: "Generates_corresponding_d_ts_file_6002", message: "Generates corresponding '.d.ts' file." },
@@ -1865,6 +1877,7 @@ var ts;
         Do_not_emit_comments_to_output: { code: 6009, category: ts.DiagnosticCategory.Message, key: "Do_not_emit_comments_to_output_6009", message: "Do not emit comments to output." },
         Do_not_emit_outputs: { code: 6010, category: ts.DiagnosticCategory.Message, key: "Do_not_emit_outputs_6010", message: "Do not emit outputs." },
         Allow_default_imports_from_modules_with_no_default_export_This_does_not_affect_code_emit_just_typechecking: { code: 6011, category: ts.DiagnosticCategory.Message, key: "Allow_default_imports_from_modules_with_no_default_export_This_does_not_affect_code_emit_just_typech_6011", message: "Allow default imports from modules with no default export. This does not affect code emit, just typechecking." },
+        Skip_type_checking_of_declaration_files: { code: 6012, category: ts.DiagnosticCategory.Message, key: "Skip_type_checking_of_declaration_files_6012", message: "Skip type checking of declaration files." },
         Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015: { code: 6015, category: ts.DiagnosticCategory.Message, key: "Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015_6015", message: "Specify ECMAScript target version: 'ES3' (default), 'ES5', or 'ES2015'" },
         Specify_module_code_generation_Colon_commonjs_amd_system_umd_or_es2015: { code: 6016, category: ts.DiagnosticCategory.Message, key: "Specify_module_code_generation_Colon_commonjs_amd_system_umd_or_es2015_6016", message: "Specify module code generation: 'commonjs', 'amd', 'system', 'umd' or 'es2015'" },
         Print_this_message: { code: 6017, category: ts.DiagnosticCategory.Message, key: "Print_this_message_6017", message: "Print this message." },
@@ -1966,6 +1979,7 @@ var ts;
         Resolving_type_reference_directive_0_containing_file_not_set_root_directory_not_set: { code: 6128, category: ts.DiagnosticCategory.Message, key: "Resolving_type_reference_directive_0_containing_file_not_set_root_directory_not_set_6128", message: "======== Resolving type reference directive '{0}', containing file not set, root directory not set. ========" },
         The_config_file_0_found_doesn_t_contain_any_source_files: { code: 6129, category: ts.DiagnosticCategory.Error, key: "The_config_file_0_found_doesn_t_contain_any_source_files_6129", message: "The config file '{0}' found doesn't contain any source files." },
         Resolving_real_path_for_0_result_1: { code: 6130, category: ts.DiagnosticCategory.Message, key: "Resolving_real_path_for_0_result_1_6130", message: "Resolving real path for '{0}', result '{1}'" },
+        Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system: { code: 6131, category: ts.DiagnosticCategory.Error, key: "Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system_6131", message: "Cannot compile modules using option '{0}' unless the '--module' flag is 'amd' or 'system'." },
         Variable_0_implicitly_has_an_1_type: { code: 7005, category: ts.DiagnosticCategory.Error, key: "Variable_0_implicitly_has_an_1_type_7005", message: "Variable '{0}' implicitly has an '{1}' type." },
         Parameter_0_implicitly_has_an_1_type: { code: 7006, category: ts.DiagnosticCategory.Error, key: "Parameter_0_implicitly_has_an_1_type_7006", message: "Parameter '{0}' implicitly has an '{1}' type." },
         Member_0_implicitly_has_an_1_type: { code: 7008, category: ts.DiagnosticCategory.Error, key: "Member_0_implicitly_has_an_1_type_7008", message: "Member '{0}' implicitly has an '{1}' type." },
@@ -5004,7 +5018,7 @@ var ts;
     }
     ts.isWellKnownSymbolSyntactically = isWellKnownSymbolSyntactically;
     function getPropertyNameForPropertyNameNode(name) {
-        if (name.kind === 69 || name.kind === 9 || name.kind === 8) {
+        if (name.kind === 69 || name.kind === 9 || name.kind === 8 || name.kind === 142) {
             return name.text;
         }
         if (name.kind === 140) {
@@ -12050,10 +12064,10 @@ var ts;
                 case 145:
                 case 144:
                 case 266:
-                    return bindPropertyOrMethodOrAccessor(node, 4 | (node.questionToken ? 536870912 : 0), 107455);
+                    return bindPropertyOrMethodOrAccessor(node, 4 | (node.questionToken ? 536870912 : 0), 0);
                 case 253:
                 case 254:
-                    return bindPropertyOrMethodOrAccessor(node, 4, 107455);
+                    return bindPropertyOrMethodOrAccessor(node, 4, 0);
                 case 255:
                     return bindPropertyOrMethodOrAccessor(node, 8, 107455);
                 case 247:
@@ -12065,7 +12079,7 @@ var ts;
                     return declareSymbolAndAddToSymbolTable(node, 131072, 0);
                 case 147:
                 case 146:
-                    return bindPropertyOrMethodOrAccessor(node, 8192 | (node.questionToken ? 536870912 : 0), ts.isObjectLiteralMethod(node) ? 107455 : 99263);
+                    return bindPropertyOrMethodOrAccessor(node, 8192 | (node.questionToken ? 536870912 : 0), ts.isObjectLiteralMethod(node) ? 0 : 99263);
                 case 220:
                     return bindFunctionDeclaration(node);
                 case 148:
@@ -12108,7 +12122,7 @@ var ts;
                 case 238:
                     return declareSymbolAndAddToSymbolTable(node, 8388608, 8388608);
                 case 228:
-                    return bindGlobalModuleExportDeclaration(node);
+                    return bindNamespaceExportDeclaration(node);
                 case 231:
                     return bindImportClause(node);
                 case 236:
@@ -12144,13 +12158,13 @@ var ts;
                 bindAnonymousDeclaration(node, 8388608, getDeclarationName(node));
             }
             else if (boundExpression.kind === 69 && node.kind === 235) {
-                declareSymbol(container.symbol.exports, container.symbol, node, 8388608, 107455 | 8388608);
+                declareSymbol(container.symbol.exports, container.symbol, node, 8388608, 0 | 8388608);
             }
             else {
-                declareSymbol(container.symbol.exports, container.symbol, node, 4, 107455 | 8388608);
+                declareSymbol(container.symbol.exports, container.symbol, node, 4, 0 | 8388608);
             }
         }
-        function bindGlobalModuleExportDeclaration(node) {
+        function bindNamespaceExportDeclaration(node) {
             if (node.modifiers && node.modifiers.length) {
                 file.bindDiagnostics.push(ts.createDiagnosticForNode(node, ts.Diagnostics.Modifiers_cannot_appear_here));
             }
@@ -12202,7 +12216,7 @@ var ts;
         function bindThisPropertyAssignment(node) {
             if (container.kind === 179 || container.kind === 220) {
                 container.symbol.members = container.symbol.members || {};
-                declareSymbol(container.symbol.members, container.symbol, node, 4, 107455 & ~4);
+                declareSymbol(container.symbol.members, container.symbol, node, 4, 0 & ~4);
             }
         }
         function bindPrototypePropertyAssignment(node) {
@@ -12219,7 +12233,7 @@ var ts;
             if (!funcSymbol.members) {
                 funcSymbol.members = {};
             }
-            declareSymbol(funcSymbol.members, funcSymbol, leftSideOfAssignment, 4, 107455);
+            declareSymbol(funcSymbol.members, funcSymbol, leftSideOfAssignment, 4, 0);
         }
         function bindCallExpression(node) {
             if (!file.commonJsModuleIndicator && ts.isRequireCall(node, false)) {
@@ -12295,7 +12309,7 @@ var ts;
             }
             if (ts.isParameterPropertyDeclaration(node)) {
                 var classDeclaration = node.parent.parent;
-                declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, 4, 107455);
+                declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, 4, 0);
             }
         }
         function bindFunctionDeclaration(node) {
@@ -12595,7 +12609,7 @@ var ts;
             if (flags & 1)
                 result |= 107454;
             if (flags & 4)
-                result |= 107455;
+                result |= 0;
             if (flags & 8)
                 result |= 107455;
             if (flags & 16)
@@ -12851,6 +12865,7 @@ var ts;
             var propertyWithInvalidInitializer;
             var errorLocation = location;
             var grandparent;
+            var isInExternalModule = false;
             loop: while (location) {
                 if (location.locals && !isGlobalSourceFile(location)) {
                     if (result = getSymbol(location.locals, name, meaning)) {
@@ -12882,6 +12897,7 @@ var ts;
                     case 256:
                         if (!ts.isExternalOrCommonJsModule(location))
                             break;
+                        isInExternalModule = true;
                     case 225:
                         var moduleExports = getSymbolOfNode(location).exports;
                         if (location.kind === 256 || ts.isAmbientModule(location)) {
@@ -13005,6 +13021,12 @@ var ts;
                         checkResolvedBlockScopedVariable(exportOrLocalSymbol, errorLocation);
                     }
                 }
+                if (result && isInExternalModule) {
+                    var decls = result.declarations;
+                    if (decls && decls.length === 1 && decls[0].kind === 228) {
+                        error(errorLocation, ts.Diagnostics.Identifier_0_must_be_imported_from_a_module, name);
+                    }
+                }
             }
             return result;
         }
@@ -14480,7 +14502,7 @@ var ts;
         }
         function getTypeForBindingElementParent(node) {
             var symbol = getSymbolOfNode(node);
-            return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node);
+            return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node, false);
         }
         function getTextOfPropertyName(name) {
             switch (name.kind) {
@@ -14585,7 +14607,7 @@ var ts;
         function addOptionality(type, optional) {
             return strictNullChecks && optional ? addNullableKind(type, 32) : type;
         }
-        function getTypeForVariableLikeDeclaration(declaration) {
+        function getTypeForVariableLikeDeclaration(declaration, includeOptionality) {
             if (declaration.flags & 134217728) {
                 var type = getTypeForVariableLikeDeclarationFromJSDocComment(declaration);
                 if (type && type !== unknownType) {
@@ -14602,7 +14624,7 @@ var ts;
                 return getTypeForBindingElement(declaration);
             }
             if (declaration.type) {
-                return addOptionality(getTypeFromTypeNode(declaration.type), !!declaration.questionToken);
+                return addOptionality(getTypeFromTypeNode(declaration.type), declaration.questionToken && includeOptionality);
             }
             if (declaration.kind === 142) {
                 var func = declaration.parent;
@@ -14621,11 +14643,11 @@ var ts;
                     ? getContextuallyTypedThisType(func)
                     : getContextuallyTypedParameterType(declaration);
                 if (type) {
-                    return addOptionality(type, !!declaration.questionToken);
+                    return addOptionality(type, declaration.questionToken && includeOptionality);
                 }
             }
             if (declaration.initializer) {
-                return addOptionality(checkExpressionCached(declaration.initializer), !!declaration.questionToken);
+                return addOptionality(checkExpressionCached(declaration.initializer), declaration.questionToken && includeOptionality);
             }
             if (declaration.kind === 254) {
                 return checkIdentifier(declaration.name);
@@ -14693,7 +14715,7 @@ var ts;
                 : getTypeFromArrayBindingPattern(pattern, includePatternInType);
         }
         function getWidenedTypeForVariableLikeDeclaration(declaration, reportErrors) {
-            var type = getTypeForVariableLikeDeclaration(declaration);
+            var type = getTypeForVariableLikeDeclaration(declaration, true);
             if (type) {
                 if (reportErrors) {
                     reportErrorsFromWidening(declaration, type);
@@ -17010,7 +17032,7 @@ var ts;
                     return isIdenticalTo(source, target);
                 }
                 if (!(target.flags & 134217728)) {
-                    if (target.flags & 1)
+                    if (target.flags & 1 || source.flags & 134217728)
                         return -1;
                     if (source.flags & 32) {
                         if (!strictNullChecks || target.flags & (32 | 16) || source === emptyArrayElementType)
@@ -17030,7 +17052,7 @@ var ts;
                     if (source.flags & 256 && target === stringType)
                         return -1;
                     if (relation === assignableRelation || relation === comparableRelation) {
-                        if (source.flags & (1 | 134217728))
+                        if (source.flags & 1)
                             return -1;
                         if (source === numberType && target.flags & 128)
                             return -1;
@@ -17807,41 +17829,47 @@ var ts;
                 getSignaturesOfType(type, 0).length === 0 &&
                 getSignaturesOfType(type, 1).length === 0;
         }
+        function createTransientSymbol(source, type) {
+            var symbol = createSymbol(source.flags | 67108864, source.name);
+            symbol.declarations = source.declarations;
+            symbol.parent = source.parent;
+            symbol.type = type;
+            symbol.target = source;
+            if (source.valueDeclaration) {
+                symbol.valueDeclaration = source.valueDeclaration;
+            }
+            return symbol;
+        }
+        function transformTypeOfMembers(type, f) {
+            var members = {};
+            for (var _i = 0, _a = getPropertiesOfObjectType(type); _i < _a.length; _i++) {
+                var property = _a[_i];
+                var original = getTypeOfSymbol(property);
+                var updated = f(original);
+                members[property.name] = updated === original ? property : createTransientSymbol(property, updated);
+            }
+            ;
+            return members;
+        }
         function getRegularTypeOfObjectLiteral(type) {
-            if (type.flags & 1048576) {
-                var regularType = type.regularType;
-                if (!regularType) {
-                    regularType = createType(type.flags & ~1048576);
-                    regularType.symbol = type.symbol;
-                    regularType.members = type.members;
-                    regularType.properties = type.properties;
-                    regularType.callSignatures = type.callSignatures;
-                    regularType.constructSignatures = type.constructSignatures;
-                    regularType.stringIndexInfo = type.stringIndexInfo;
-                    regularType.numberIndexInfo = type.numberIndexInfo;
-                    type.regularType = regularType;
-                }
+            if (!(type.flags & 1048576)) {
+                return type;
+            }
+            var regularType = type.regularType;
+            if (regularType) {
                 return regularType;
             }
-            return type;
+            var resolved = type;
+            var members = transformTypeOfMembers(type, getRegularTypeOfObjectLiteral);
+            var regularNew = createAnonymousType(resolved.symbol, members, resolved.callSignatures, resolved.constructSignatures, resolved.stringIndexInfo, resolved.numberIndexInfo);
+            regularNew.flags = resolved.flags & ~1048576;
+            type.regularType = regularNew;
+            return regularNew;
         }
         function getWidenedTypeOfObjectLiteral(type) {
-            var properties = getPropertiesOfObjectType(type);
-            var members = {};
-            ts.forEach(properties, function (p) {
-                var propType = getTypeOfSymbol(p);
-                var widenedType = getWidenedType(propType);
-                if (propType !== widenedType) {
-                    var symbol = createSymbol(p.flags | 67108864, p.name);
-                    symbol.declarations = p.declarations;
-                    symbol.parent = p.parent;
-                    symbol.type = widenedType;
-                    symbol.target = p;
-                    if (p.valueDeclaration)
-                        symbol.valueDeclaration = p.valueDeclaration;
-                    p = symbol;
-                }
-                members[p.name] = p;
+            var members = transformTypeOfMembers(type, function (prop) {
+                var widened = getWidenedType(prop);
+                return prop === widened ? prop : widened;
             });
             var stringIndexInfo = getIndexInfoOfType(type, 0);
             var numberIndexInfo = getIndexInfoOfType(type, 1);
@@ -19134,7 +19162,7 @@ var ts;
             }
             return nodeCheckFlag === 512
                 ? getBaseConstructorTypeOfClass(classType)
-                : baseClassType;
+                : getTypeWithThisArgument(baseClassType, classType.thisType);
             function isLegalUsageOfSuperExpression(container) {
                 if (!container) {
                     return false;
@@ -21182,7 +21210,7 @@ var ts;
                 var types = void 0;
                 var funcIsGenerator = !!func.asteriskToken;
                 if (funcIsGenerator) {
-                    types = checkAndAggregateYieldOperandTypes(func.body, contextualMapper);
+                    types = checkAndAggregateYieldOperandTypes(func, contextualMapper);
                     if (types.length === 0) {
                         var iterableIteratorAny = createIterableIteratorType(anyType);
                         if (compilerOptions.noImplicitAny) {
@@ -21192,8 +21220,7 @@ var ts;
                     }
                 }
                 else {
-                    var hasImplicitReturn = !!(func.flags & 32768);
-                    types = checkAndAggregateReturnExpressionTypes(func.body, contextualMapper, isAsync, hasImplicitReturn);
+                    types = checkAndAggregateReturnExpressionTypes(func, contextualMapper);
                     if (!types) {
                         return neverType;
                     }
@@ -21240,9 +21267,9 @@ var ts;
                 return widenedType;
             }
         }
-        function checkAndAggregateYieldOperandTypes(body, contextualMapper) {
+        function checkAndAggregateYieldOperandTypes(func, contextualMapper) {
             var aggregatedTypes = [];
-            ts.forEachYieldExpression(body, function (yieldExpression) {
+            ts.forEachYieldExpression(func.body, function (yieldExpression) {
                 var expr = yieldExpression.expression;
                 if (expr) {
                     var type = checkExpressionCached(expr, contextualMapper);
@@ -21256,28 +21283,34 @@ var ts;
             });
             return aggregatedTypes;
         }
-        function checkAndAggregateReturnExpressionTypes(body, contextualMapper, isAsync, hasImplicitReturn) {
+        function checkAndAggregateReturnExpressionTypes(func, contextualMapper) {
+            var isAsync = ts.isAsyncFunctionLike(func);
             var aggregatedTypes = [];
-            var hasOmittedExpressions = false;
-            ts.forEachReturnStatement(body, function (returnStatement) {
+            var hasReturnWithNoExpression = !!(func.flags & 32768);
+            var hasReturnOfTypeNever = false;
+            ts.forEachReturnStatement(func.body, function (returnStatement) {
                 var expr = returnStatement.expression;
                 if (expr) {
                     var type = checkExpressionCached(expr, contextualMapper);
                     if (isAsync) {
-                        type = checkAwaitedType(type, body.parent, ts.Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
+                        type = checkAwaitedType(type, func, ts.Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
                     }
-                    if (type !== neverType && !ts.contains(aggregatedTypes, type)) {
+                    if (type === neverType) {
+                        hasReturnOfTypeNever = true;
+                    }
+                    else if (!ts.contains(aggregatedTypes, type)) {
                         aggregatedTypes.push(type);
                     }
                 }
                 else {
-                    hasOmittedExpressions = true;
+                    hasReturnWithNoExpression = true;
                 }
             });
-            if (aggregatedTypes.length === 0 && !hasOmittedExpressions && !hasImplicitReturn) {
+            if (aggregatedTypes.length === 0 && !hasReturnWithNoExpression && (hasReturnOfTypeNever ||
+                func.kind === 179 || func.kind === 180)) {
                 return undefined;
             }
-            if (strictNullChecks && aggregatedTypes.length && (hasOmittedExpressions || hasImplicitReturn)) {
+            if (strictNullChecks && aggregatedTypes.length && hasReturnWithNoExpression) {
                 if (!ts.contains(aggregatedTypes, undefinedType)) {
                     aggregatedTypes.push(undefinedType);
                 }
@@ -21407,7 +21440,9 @@ var ts;
                     (expr.kind === 172 || expr.kind === 173) &&
                     expr.expression.kind === 97) {
                     var func = ts.getContainingFunction(expr);
-                    return !(func && func.kind === 148 && func.parent === symbol.valueDeclaration.parent);
+                    if (!(func && func.kind === 148))
+                        return true;
+                    return !(func.parent === symbol.valueDeclaration.parent || func === symbol.valueDeclaration.parent);
                 }
                 return true;
             }
@@ -22231,6 +22266,79 @@ var ts;
                 }
             }
         }
+        function checkClassForDuplicateDeclarations(node) {
+            var getter = 1, setter = 2, property = getter | setter;
+            var instanceNames = {};
+            var staticNames = {};
+            for (var _i = 0, _a = node.members; _i < _a.length; _i++) {
+                var member = _a[_i];
+                if (member.kind === 148) {
+                    for (var _b = 0, _c = member.parameters; _b < _c.length; _b++) {
+                        var param = _c[_b];
+                        if (ts.isParameterPropertyDeclaration(param)) {
+                            addName(instanceNames, param.name, param.name.text, property);
+                        }
+                    }
+                }
+                else {
+                    var static = ts.forEach(member.modifiers, function (m) { return m.kind === 113; });
+                    var names = static ? staticNames : instanceNames;
+                    var memberName = member.name && ts.getPropertyNameForPropertyNameNode(member.name);
+                    if (memberName) {
+                        switch (member.kind) {
+                            case 149:
+                                addName(names, member.name, memberName, getter);
+                                break;
+                            case 150:
+                                addName(names, member.name, memberName, setter);
+                                break;
+                            case 145:
+                                addName(names, member.name, memberName, property);
+                                break;
+                        }
+                    }
+                }
+            }
+            function addName(names, location, name, meaning) {
+                if (ts.hasProperty(names, name)) {
+                    var prev = names[name];
+                    if (prev & meaning) {
+                        error(location, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(location));
+                    }
+                    else {
+                        names[name] = prev | meaning;
+                    }
+                }
+                else {
+                    names[name] = meaning;
+                }
+            }
+        }
+        function checkObjectTypeForDuplicateDeclarations(node) {
+            var names = {};
+            for (var _i = 0, _a = node.members; _i < _a.length; _i++) {
+                var member = _a[_i];
+                if (member.kind == 144) {
+                    var memberName = void 0;
+                    switch (member.name.kind) {
+                        case 9:
+                        case 8:
+                        case 69:
+                            memberName = member.name.text;
+                            break;
+                        default:
+                            continue;
+                    }
+                    if (ts.hasProperty(names, memberName)) {
+                        error(member.symbol.valueDeclaration.name, ts.Diagnostics.Duplicate_identifier_0, memberName);
+                        error(member.name, ts.Diagnostics.Duplicate_identifier_0, memberName);
+                    }
+                    else {
+                        names[memberName] = true;
+                    }
+                }
+            }
+        }
         function checkTypeForDuplicateIndexSignatures(node) {
             if (node.kind === 222) {
                 var nodeSymbol = getSymbolOfNode(node);
@@ -22449,6 +22557,7 @@ var ts;
                 var type = getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node);
                 checkIndexConstraints(type);
                 checkTypeForDuplicateIndexSignatures(node);
+                checkObjectTypeForDuplicateDeclarations(node);
             }
         }
         function checkArrayType(node) {
@@ -23208,6 +23317,10 @@ var ts;
                 if (node.initializer) {
                     checkTypeAssignableTo(checkExpressionCached(node.initializer), declarationType, node, undefined);
                 }
+                if (!areDeclarationFlagsIdentical(node, symbol.valueDeclaration)) {
+                    error(symbol.valueDeclaration.name, ts.Diagnostics.All_declarations_of_0_must_have_identical_modifiers, ts.declarationNameToString(node.name));
+                    error(node.name, ts.Diagnostics.All_declarations_of_0_must_have_identical_modifiers, ts.declarationNameToString(node.name));
+                }
             }
             if (node.kind !== 145 && node.kind !== 144) {
                 checkExportsOnMergedDeclarations(node);
@@ -23220,6 +23333,18 @@ var ts;
                 checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name);
             }
         }
+        function areDeclarationFlagsIdentical(left, right) {
+            if (ts.hasQuestionToken(left) !== ts.hasQuestionToken(right)) {
+                return false;
+            }
+            var interestingFlags = 8 |
+                16 |
+                256 |
+                128 |
+                64 |
+                32;
+            return (left.flags & interestingFlags) === (right.flags & interestingFlags);
+        }
         function checkVariableDeclaration(node) {
             checkGrammarVariableDeclaration(node);
             return checkVariableLikeDeclaration(node);
@@ -23770,6 +23895,7 @@ var ts;
             var typeWithThis = getTypeWithThisArgument(type);
             var staticType = getTypeOfSymbol(symbol);
             checkTypeParameterListsIdentical(node, symbol);
+            checkClassForDuplicateDeclarations(node);
             var baseTypeNode = ts.getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
                 var baseTypes = getBaseTypes(type);
@@ -23981,6 +24107,7 @@ var ts;
                         checkIndexConstraints(type);
                     }
                 }
+                checkObjectTypeForDuplicateDeclarations(node);
             }
             ts.forEach(ts.getInterfaceBaseTypeNodes(node), function (heritageElement) {
                 if (!ts.isSupportedExpressionWithTypeArguments(heritageElement)) {
@@ -24735,10 +24862,8 @@ var ts;
         function checkSourceFileWorker(node) {
             var links = getNodeLinks(node);
             if (!(links.flags & 1)) {
-                if (compilerOptions.skipDefaultLibCheck) {
-                    if (node.hasNoDefaultLib) {
-                        return;
-                    }
+                if (compilerOptions.skipLibCheck && node.isDeclarationFile || compilerOptions.skipDefaultLibCheck && node.hasNoDefaultLib) {
+                    return;
                 }
                 checkGrammarSourceFile(node);
                 potentialThisCollisions.length = 0;
@@ -25107,7 +25232,7 @@ var ts;
                 return symbol && getTypeOfSymbol(symbol);
             }
             if (ts.isBindingPattern(node)) {
-                return getTypeForVariableLikeDeclaration(node.parent);
+                return getTypeForVariableLikeDeclaration(node.parent, true);
             }
             if (isInRightSideOfImportOrExportAssignment(node)) {
                 var symbol = getSymbolAtLocation(node);
@@ -25546,7 +25671,7 @@ var ts;
                 if (file.moduleAugmentations.length) {
                     (augmentations || (augmentations = [])).push(file.moduleAugmentations);
                 }
-                if (file.wasReferenced && file.symbol && file.symbol.globalExports) {
+                if (file.symbol && file.symbol.globalExports) {
                     mergeSymbolTable(globals, file.symbol.globalExports);
                 }
             });
@@ -26116,7 +26241,6 @@ var ts;
                 if (prop.kind === 193 ||
                     name_20.kind === 140) {
                     checkGrammarComputedPropertyName(name_20);
-                    return "continue";
                 }
                 if (prop.kind === 254 && !inDestructuring && prop.objectAssignmentInitializer) {
                     return { value: grammarErrorOnNode(prop.equalsToken, ts.Diagnostics.can_only_be_used_in_an_object_literal_property_inside_a_destructuring_assignment) };
@@ -26146,17 +26270,21 @@ var ts;
                 else {
                     ts.Debug.fail("Unexpected syntax kind:" + prop.kind);
                 }
-                if (!ts.hasProperty(seen, name_20.text)) {
-                    seen[name_20.text] = currentKind;
+                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_20);
+                if (effectiveName === undefined) {
+                    return "continue";
+                }
+                if (!ts.hasProperty(seen, effectiveName)) {
+                    seen[effectiveName] = currentKind;
                 }
                 else {
-                    var existingKind = seen[name_20.text];
+                    var existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
-                        return "continue";
+                        grammarErrorOnNode(name_20, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_20));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
-                            seen[name_20.text] = currentKind | existingKind;
+                            seen[effectiveName] = currentKind | existingKind;
                         }
                         else {
                             return { value: grammarErrorOnNode(name_20, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name) };
@@ -34613,7 +34741,7 @@ var ts;
             skipTsx: true,
             traceEnabled: traceEnabled
         };
-        var rootDir = options.typesRoot || (options.configFilePath ? ts.getDirectoryPath(options.configFilePath) : undefined);
+        var rootDir = options.typesRoot || (options.configFilePath ? ts.getDirectoryPath(options.configFilePath) : (host.getCurrentDirectory && host.getCurrentDirectory()));
         if (traceEnabled) {
             if (containingFile === undefined) {
                 if (rootDir === undefined) {
@@ -35116,12 +35244,25 @@ var ts;
                 }
             }
         }
+        function getDefaultTypeDirectiveNames(rootPath) {
+            var localTypes = ts.combinePaths(rootPath, "types");
+            var npmTypes = ts.combinePaths(rootPath, "node_modules/@types");
+            var result = [];
+            if (ts.sys.directoryExists(localTypes)) {
+                result = result.concat(ts.sys.getDirectories(localTypes));
+            }
+            if (ts.sys.directoryExists(npmTypes)) {
+                result = result.concat(ts.sys.getDirectories(npmTypes));
+            }
+            return result;
+        }
         function getDefaultLibLocation() {
             return ts.getDirectoryPath(ts.normalizePath(ts.sys.getExecutingFilePath()));
         }
         var newLine = ts.getNewLineCharacter(options);
         var realpath = ts.sys.realpath && (function (path) { return ts.sys.realpath(path); });
         return {
+            getDefaultTypeDirectiveNames: getDefaultTypeDirectiveNames,
             getSourceFile: getSourceFile,
             getDefaultLibLocation: getDefaultLibLocation,
             getDefaultLibFileName: function (options) { return ts.combinePaths(getDefaultLibLocation(), ts.getDefaultLibFileName(options)); },
@@ -35189,6 +35330,19 @@ var ts;
         }
         return resolutions;
     }
+    function getDefaultTypeDirectiveNames(options, rootFiles, host) {
+        if (options.types) {
+            return options.types;
+        }
+        if (host && host.getDefaultTypeDirectiveNames) {
+            var commonRoot = computeCommonSourceDirectoryOfFilenames(rootFiles, host.getCurrentDirectory(), function (f) { return host.getCanonicalFileName(f); });
+            if (commonRoot) {
+                return host.getDefaultTypeDirectiveNames(commonRoot);
+            }
+        }
+        return undefined;
+    }
+    ts.getDefaultTypeDirectiveNames = getDefaultTypeDirectiveNames;
     function createProgram(rootNames, options, host, oldProgram) {
         var program;
         var files = [];
@@ -35224,13 +35378,14 @@ var ts;
         var filesByName = ts.createFileMap();
         var filesByNameIgnoreCase = host.useCaseSensitiveFileNames() ? ts.createFileMap(function (fileName) { return fileName.toLowerCase(); }) : undefined;
         if (!tryReuseStructureFromOldProgram()) {
-            if (options.types && options.types.length) {
-                var resolutions = resolveTypeReferenceDirectiveNamesWorker(options.types, undefined);
-                for (var i = 0; i < options.types.length; i++) {
-                    processTypeReferenceDirective(options.types[i], resolutions[i]);
+            ts.forEach(rootNames, function (name) { return processRootFile(name, false); });
+            var typeReferences = getDefaultTypeDirectiveNames(options, rootNames, host);
+            if (typeReferences) {
+                var resolutions = resolveTypeReferenceDirectiveNamesWorker(typeReferences, undefined);
+                for (var i = 0; i < typeReferences.length; i++) {
+                    processTypeReferenceDirective(typeReferences[i], resolutions[i]);
                 }
             }
-            ts.forEach(rootNames, function (name) { return processRootFile(name, false); });
             if (!skipDefaultLib) {
                 if (!options.lib) {
                     processRootFile(host.getDefaultLibFileName(options), true);
@@ -35807,9 +35962,6 @@ var ts;
                 if (file_1 && options.forceConsistentCasingInFileNames && ts.getNormalizedAbsolutePath(file_1.fileName, currentDirectory) !== ts.getNormalizedAbsolutePath(fileName, currentDirectory)) {
                     reportFileNamesDifferOnlyInCasingError(fileName, file_1.fileName, refFile, refPos, refEnd);
                 }
-                if (file_1) {
-                    file_1.wasReferenced = file_1.wasReferenced || isReference;
-                }
                 return file_1;
             }
             var file = host.getSourceFile(fileName, options.target, function (hostErrorMessage) {
@@ -35822,7 +35974,6 @@ var ts;
             });
             filesByName.set(path, file);
             if (file) {
-                file.wasReferenced = file.wasReferenced || isReference;
                 file.path = path;
                 if (host.useCaseSensitiveFileNames()) {
                     var existingFile = filesByNameIgnoreCase.get(path);
@@ -35923,17 +36074,7 @@ var ts;
                         !options.noResolve &&
                         i < file.imports.length;
                     if (shouldAddFile) {
-                        var importedFile = findSourceFile(resolution.resolvedFileName, ts.toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName), false, false, file, ts.skipTrivia(file.text, file.imports[i].pos), file.imports[i].end);
-                        if (importedFile && resolution.isExternalLibraryImport) {
-                            if (!ts.isExternalModule(importedFile) && importedFile.statements.length) {
-                                var start_5 = ts.getTokenPosOfNode(file.imports[i], file);
-                                fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_5, file.imports[i].end - start_5, 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 (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));
-                            }
-                        }
+                        findSourceFile(resolution.resolvedFileName, ts.toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName), false, false, file, ts.skipTrivia(file.text, file.imports[i].pos), file.imports[i].end);
                     }
                 }
             }
@@ -36018,7 +36159,7 @@ var ts;
                         }
                     }
                     else {
-                        programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Substututions_for_pattern_0_should_be_an_array, key));
+                        programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Substitutions_for_pattern_0_should_be_an_array, key));
                     }
                 }
             }
@@ -36067,13 +36208,19 @@ var ts;
             }
             else if (firstExternalModuleSourceFile && languageVersion < 2 && options.module === ts.ModuleKind.None) {
                 var span = ts.getErrorSpanForNode(firstExternalModuleSourceFile, firstExternalModuleSourceFile.externalModuleIndicator);
-                programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file));
+                programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_use_imports_exports_or_module_augmentations_when_module_is_none));
             }
             if (options.module === ts.ModuleKind.ES6 && languageVersion < 2) {
                 programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Cannot_compile_modules_into_es2015_when_targeting_ES5_or_lower));
             }
-            if (outFile && options.module && !(options.module === ts.ModuleKind.AMD || options.module === ts.ModuleKind.System)) {
-                programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Only_amd_and_system_modules_are_supported_alongside_0, options.out ? "out" : "outFile"));
+            if (outFile) {
+                if (options.module && !(options.module === ts.ModuleKind.AMD || options.module === ts.ModuleKind.System)) {
+                    programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Only_amd_and_system_modules_are_supported_alongside_0, options.out ? "out" : "outFile"));
+                }
+                else if (options.module === undefined && firstExternalModuleSourceFile) {
+                    var span = ts.getErrorSpanForNode(firstExternalModuleSourceFile, firstExternalModuleSourceFile.externalModuleIndicator);
+                    programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system, options.out ? "out" : "outFile"));
+                }
             }
             if (options.outDir ||
                 options.sourceRoot ||
@@ -36156,6 +36303,11 @@ var ts;
             type: "boolean",
             description: ts.Diagnostics.Print_this_message
         },
+        {
+            name: "help",
+            shortName: "?",
+            type: "boolean"
+        },
         {
             name: "init",
             type: "boolean",
@@ -36258,6 +36410,11 @@ var ts;
             name: "skipDefaultLibCheck",
             type: "boolean"
         },
+        {
+            name: "skipLibCheck",
+            type: "boolean",
+            description: ts.Diagnostics.Skip_type_checking_of_declaration_files
+        },
         {
             name: "out",
             type: "string",
diff --git a/lib/tsserver.js b/lib/tsserver.js
index ecb7bfb5509..7eb744a77d3 100644
--- a/lib/tsserver.js
+++ b/lib/tsserver.js
@@ -918,6 +918,10 @@ var ts;
                 }
                 return result.sort();
             }
+            function getDirectories(path) {
+                var folder = fso.GetFolder(path);
+                return getNames(folder.subfolders);
+            }
             function readDirectory(path, extension, exclude) {
                 var result = [];
                 exclude = ts.map(exclude, function (s) { return getCanonicalPath(ts.combinePaths(path, s)); });
@@ -972,6 +976,7 @@ var ts;
                 getCurrentDirectory: function () {
                     return new ActiveXObject("WScript.Shell").CurrentDirectory;
                 },
+                getDirectories: getDirectories,
                 readDirectory: readDirectory,
                 exit: function (exitCode) {
                     try {
@@ -1119,6 +1124,9 @@ var ts;
             function directoryExists(path) {
                 return fileSystemEntryExists(path, 1);
             }
+            function getDirectories(path) {
+                return ts.filter(_fs.readdirSync(path), function (p) { return fileSystemEntryExists(ts.combinePaths(path, p), 1); });
+            }
             function readDirectory(path, extension, exclude) {
                 var result = [];
                 exclude = ts.map(exclude, function (s) { return getCanonicalPath(ts.combinePaths(path, s)); });
@@ -1211,6 +1219,7 @@ var ts;
                 getCurrentDirectory: function () {
                     return process.cwd();
                 },
+                getDirectories: getDirectories,
                 readDirectory: readDirectory,
                 getModifiedTime: function (path) {
                     try {
@@ -1261,6 +1270,7 @@ var ts;
                 createDirectory: ChakraHost.createDirectory,
                 getExecutingFilePath: function () { return ChakraHost.executingFile; },
                 getCurrentDirectory: function () { return ChakraHost.currentDirectory; },
+                getDirectories: ChakraHost.getDirectories,
                 readDirectory: ChakraHost.readDirectory,
                 exit: ChakraHost.quit,
                 realpath: realpath
@@ -1394,7 +1404,7 @@ var ts;
         or_expected: { code: 1144, category: ts.DiagnosticCategory.Error, key: "or_expected_1144", message: "'{' or ';' expected." },
         Declaration_expected: { code: 1146, category: ts.DiagnosticCategory.Error, key: "Declaration_expected_1146", message: "Declaration expected." },
         Import_declarations_in_a_namespace_cannot_reference_a_module: { code: 1147, category: ts.DiagnosticCategory.Error, key: "Import_declarations_in_a_namespace_cannot_reference_a_module_1147", message: "Import declarations in a namespace cannot reference a module." },
-        Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file: { code: 1148, category: ts.DiagnosticCategory.Error, key: "Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting__1148", message: "Cannot compile modules unless the '--module' flag is provided with a valid module type. Consider setting the 'module' compiler option in a 'tsconfig.json' file." },
+        Cannot_use_imports_exports_or_module_augmentations_when_module_is_none: { code: 1148, category: ts.DiagnosticCategory.Error, key: "Cannot_use_imports_exports_or_module_augmentations_when_module_is_none_1148", message: "Cannot use imports, exports, or module augmentations when '--module' is 'none'." },
         File_name_0_differs_from_already_included_file_name_1_only_in_casing: { code: 1149, category: ts.DiagnosticCategory.Error, key: "File_name_0_differs_from_already_included_file_name_1_only_in_casing_1149", message: "File name '{0}' differs from already included file name '{1}' only in casing" },
         new_T_cannot_be_used_to_create_an_array_Use_new_Array_T_instead: { code: 1150, category: ts.DiagnosticCategory.Error, key: "new_T_cannot_be_used_to_create_an_array_Use_new_Array_T_instead_1150", message: "'new T[]' cannot be used to create an array. Use 'new Array<T>()' instead." },
         const_declarations_must_be_initialized: { code: 1155, category: ts.DiagnosticCategory.Error, key: "const_declarations_must_be_initialized_1155", message: "'const' declarations must be initialized" },
@@ -1764,6 +1774,8 @@ var ts;
         this_implicitly_has_type_any_because_it_does_not_have_a_type_annotation: { code: 2683, category: ts.DiagnosticCategory.Error, key: "this_implicitly_has_type_any_because_it_does_not_have_a_type_annotation_2683", message: "'this' implicitly has type 'any' because it does not have a type annotation." },
         The_this_context_of_type_0_is_not_assignable_to_method_s_this_of_type_1: { code: 2684, category: ts.DiagnosticCategory.Error, key: "The_this_context_of_type_0_is_not_assignable_to_method_s_this_of_type_1_2684", message: "The 'this' context of type '{0}' is not assignable to method's 'this' of type '{1}'." },
         The_this_types_of_each_signature_are_incompatible: { code: 2685, category: ts.DiagnosticCategory.Error, key: "The_this_types_of_each_signature_are_incompatible_2685", message: "The 'this' types of each signature are incompatible." },
+        Identifier_0_must_be_imported_from_a_module: { code: 2686, category: ts.DiagnosticCategory.Error, key: "Identifier_0_must_be_imported_from_a_module_2686", message: "Identifier '{0}' must be imported from a module" },
+        All_declarations_of_0_must_have_identical_modifiers: { code: 2687, category: ts.DiagnosticCategory.Error, key: "All_declarations_of_0_must_have_identical_modifiers_2687", message: "All declarations of '{0}' must have identical modifiers." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: ts.DiagnosticCategory.Error, key: "Import_declaration_0_is_using_private_name_1_4000", message: "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_4002", message: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
         Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1: { code: 4004, category: ts.DiagnosticCategory.Error, key: "Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1_4004", message: "Type parameter '{0}' of exported interface has or is using private name '{1}'." },
@@ -1857,7 +1869,7 @@ var ts;
         Option_paths_cannot_be_used_without_specifying_baseUrl_option: { code: 5060, category: ts.DiagnosticCategory.Error, key: "Option_paths_cannot_be_used_without_specifying_baseUrl_option_5060", message: "Option 'paths' cannot be used without specifying '--baseUrl' option." },
         Pattern_0_can_have_at_most_one_Asterisk_character: { code: 5061, category: ts.DiagnosticCategory.Error, key: "Pattern_0_can_have_at_most_one_Asterisk_character_5061", message: "Pattern '{0}' can have at most one '*' character" },
         Substitution_0_in_pattern_1_in_can_have_at_most_one_Asterisk_character: { code: 5062, category: ts.DiagnosticCategory.Error, key: "Substitution_0_in_pattern_1_in_can_have_at_most_one_Asterisk_character_5062", message: "Substitution '{0}' in pattern '{1}' in can have at most one '*' character" },
-        Substututions_for_pattern_0_should_be_an_array: { code: 5063, category: ts.DiagnosticCategory.Error, key: "Substututions_for_pattern_0_should_be_an_array_5063", message: "Substututions for pattern '{0}' should be an array." },
+        Substitutions_for_pattern_0_should_be_an_array: { code: 5063, category: ts.DiagnosticCategory.Error, key: "Substitutions_for_pattern_0_should_be_an_array_5063", message: "Substitutions for pattern '{0}' should be an array." },
         Substitution_0_for_pattern_1_has_incorrect_type_expected_string_got_2: { code: 5064, category: ts.DiagnosticCategory.Error, key: "Substitution_0_for_pattern_1_has_incorrect_type_expected_string_got_2_5064", message: "Substitution '{0}' for pattern '{1}' has incorrect type, expected 'string', got '{2}'." },
         Concatenate_and_emit_output_to_single_file: { code: 6001, category: ts.DiagnosticCategory.Message, key: "Concatenate_and_emit_output_to_single_file_6001", message: "Concatenate and emit output to single file." },
         Generates_corresponding_d_ts_file: { code: 6002, category: ts.DiagnosticCategory.Message, key: "Generates_corresponding_d_ts_file_6002", message: "Generates corresponding '.d.ts' file." },
@@ -1870,6 +1882,7 @@ var ts;
         Do_not_emit_comments_to_output: { code: 6009, category: ts.DiagnosticCategory.Message, key: "Do_not_emit_comments_to_output_6009", message: "Do not emit comments to output." },
         Do_not_emit_outputs: { code: 6010, category: ts.DiagnosticCategory.Message, key: "Do_not_emit_outputs_6010", message: "Do not emit outputs." },
         Allow_default_imports_from_modules_with_no_default_export_This_does_not_affect_code_emit_just_typechecking: { code: 6011, category: ts.DiagnosticCategory.Message, key: "Allow_default_imports_from_modules_with_no_default_export_This_does_not_affect_code_emit_just_typech_6011", message: "Allow default imports from modules with no default export. This does not affect code emit, just typechecking." },
+        Skip_type_checking_of_declaration_files: { code: 6012, category: ts.DiagnosticCategory.Message, key: "Skip_type_checking_of_declaration_files_6012", message: "Skip type checking of declaration files." },
         Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015: { code: 6015, category: ts.DiagnosticCategory.Message, key: "Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015_6015", message: "Specify ECMAScript target version: 'ES3' (default), 'ES5', or 'ES2015'" },
         Specify_module_code_generation_Colon_commonjs_amd_system_umd_or_es2015: { code: 6016, category: ts.DiagnosticCategory.Message, key: "Specify_module_code_generation_Colon_commonjs_amd_system_umd_or_es2015_6016", message: "Specify module code generation: 'commonjs', 'amd', 'system', 'umd' or 'es2015'" },
         Print_this_message: { code: 6017, category: ts.DiagnosticCategory.Message, key: "Print_this_message_6017", message: "Print this message." },
@@ -1971,6 +1984,7 @@ var ts;
         Resolving_type_reference_directive_0_containing_file_not_set_root_directory_not_set: { code: 6128, category: ts.DiagnosticCategory.Message, key: "Resolving_type_reference_directive_0_containing_file_not_set_root_directory_not_set_6128", message: "======== Resolving type reference directive '{0}', containing file not set, root directory not set. ========" },
         The_config_file_0_found_doesn_t_contain_any_source_files: { code: 6129, category: ts.DiagnosticCategory.Error, key: "The_config_file_0_found_doesn_t_contain_any_source_files_6129", message: "The config file '{0}' found doesn't contain any source files." },
         Resolving_real_path_for_0_result_1: { code: 6130, category: ts.DiagnosticCategory.Message, key: "Resolving_real_path_for_0_result_1_6130", message: "Resolving real path for '{0}', result '{1}'" },
+        Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system: { code: 6131, category: ts.DiagnosticCategory.Error, key: "Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system_6131", message: "Cannot compile modules using option '{0}' unless the '--module' flag is 'amd' or 'system'." },
         Variable_0_implicitly_has_an_1_type: { code: 7005, category: ts.DiagnosticCategory.Error, key: "Variable_0_implicitly_has_an_1_type_7005", message: "Variable '{0}' implicitly has an '{1}' type." },
         Parameter_0_implicitly_has_an_1_type: { code: 7006, category: ts.DiagnosticCategory.Error, key: "Parameter_0_implicitly_has_an_1_type_7006", message: "Parameter '{0}' implicitly has an '{1}' type." },
         Member_0_implicitly_has_an_1_type: { code: 7008, category: ts.DiagnosticCategory.Error, key: "Member_0_implicitly_has_an_1_type_7008", message: "Member '{0}' implicitly has an '{1}' type." },
@@ -3537,6 +3551,11 @@ var ts;
             type: "boolean",
             description: ts.Diagnostics.Print_this_message
         },
+        {
+            name: "help",
+            shortName: "?",
+            type: "boolean"
+        },
         {
             name: "init",
             type: "boolean",
@@ -3639,6 +3658,11 @@ var ts;
             name: "skipDefaultLibCheck",
             type: "boolean"
         },
+        {
+            name: "skipLibCheck",
+            type: "boolean",
+            description: ts.Diagnostics.Skip_type_checking_of_declaration_files
+        },
         {
             name: "out",
             type: "string",
@@ -5758,7 +5782,7 @@ var ts;
     }
     ts.isWellKnownSymbolSyntactically = isWellKnownSymbolSyntactically;
     function getPropertyNameForPropertyNameNode(name) {
-        if (name.kind === 69 || name.kind === 9 || name.kind === 8) {
+        if (name.kind === 69 || name.kind === 9 || name.kind === 8 || name.kind === 142) {
             return name.text;
         }
         if (name.kind === 140) {
@@ -12804,10 +12828,10 @@ var ts;
                 case 145:
                 case 144:
                 case 266:
-                    return bindPropertyOrMethodOrAccessor(node, 4 | (node.questionToken ? 536870912 : 0), 107455);
+                    return bindPropertyOrMethodOrAccessor(node, 4 | (node.questionToken ? 536870912 : 0), 0);
                 case 253:
                 case 254:
-                    return bindPropertyOrMethodOrAccessor(node, 4, 107455);
+                    return bindPropertyOrMethodOrAccessor(node, 4, 0);
                 case 255:
                     return bindPropertyOrMethodOrAccessor(node, 8, 107455);
                 case 247:
@@ -12819,7 +12843,7 @@ var ts;
                     return declareSymbolAndAddToSymbolTable(node, 131072, 0);
                 case 147:
                 case 146:
-                    return bindPropertyOrMethodOrAccessor(node, 8192 | (node.questionToken ? 536870912 : 0), ts.isObjectLiteralMethod(node) ? 107455 : 99263);
+                    return bindPropertyOrMethodOrAccessor(node, 8192 | (node.questionToken ? 536870912 : 0), ts.isObjectLiteralMethod(node) ? 0 : 99263);
                 case 220:
                     return bindFunctionDeclaration(node);
                 case 148:
@@ -12862,7 +12886,7 @@ var ts;
                 case 238:
                     return declareSymbolAndAddToSymbolTable(node, 8388608, 8388608);
                 case 228:
-                    return bindGlobalModuleExportDeclaration(node);
+                    return bindNamespaceExportDeclaration(node);
                 case 231:
                     return bindImportClause(node);
                 case 236:
@@ -12898,13 +12922,13 @@ var ts;
                 bindAnonymousDeclaration(node, 8388608, getDeclarationName(node));
             }
             else if (boundExpression.kind === 69 && node.kind === 235) {
-                declareSymbol(container.symbol.exports, container.symbol, node, 8388608, 107455 | 8388608);
+                declareSymbol(container.symbol.exports, container.symbol, node, 8388608, 0 | 8388608);
             }
             else {
-                declareSymbol(container.symbol.exports, container.symbol, node, 4, 107455 | 8388608);
+                declareSymbol(container.symbol.exports, container.symbol, node, 4, 0 | 8388608);
             }
         }
-        function bindGlobalModuleExportDeclaration(node) {
+        function bindNamespaceExportDeclaration(node) {
             if (node.modifiers && node.modifiers.length) {
                 file.bindDiagnostics.push(ts.createDiagnosticForNode(node, ts.Diagnostics.Modifiers_cannot_appear_here));
             }
@@ -12956,7 +12980,7 @@ var ts;
         function bindThisPropertyAssignment(node) {
             if (container.kind === 179 || container.kind === 220) {
                 container.symbol.members = container.symbol.members || {};
-                declareSymbol(container.symbol.members, container.symbol, node, 4, 107455 & ~4);
+                declareSymbol(container.symbol.members, container.symbol, node, 4, 0 & ~4);
             }
         }
         function bindPrototypePropertyAssignment(node) {
@@ -12973,7 +12997,7 @@ var ts;
             if (!funcSymbol.members) {
                 funcSymbol.members = {};
             }
-            declareSymbol(funcSymbol.members, funcSymbol, leftSideOfAssignment, 4, 107455);
+            declareSymbol(funcSymbol.members, funcSymbol, leftSideOfAssignment, 4, 0);
         }
         function bindCallExpression(node) {
             if (!file.commonJsModuleIndicator && ts.isRequireCall(node, false)) {
@@ -13049,7 +13073,7 @@ var ts;
             }
             if (ts.isParameterPropertyDeclaration(node)) {
                 var classDeclaration = node.parent.parent;
-                declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, 4, 107455);
+                declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, 4, 0);
             }
         }
         function bindFunctionDeclaration(node) {
@@ -13349,7 +13373,7 @@ var ts;
             if (flags & 1)
                 result |= 107454;
             if (flags & 4)
-                result |= 107455;
+                result |= 0;
             if (flags & 8)
                 result |= 107455;
             if (flags & 16)
@@ -13605,6 +13629,7 @@ var ts;
             var propertyWithInvalidInitializer;
             var errorLocation = location;
             var grandparent;
+            var isInExternalModule = false;
             loop: while (location) {
                 if (location.locals && !isGlobalSourceFile(location)) {
                     if (result = getSymbol(location.locals, name, meaning)) {
@@ -13636,6 +13661,7 @@ var ts;
                     case 256:
                         if (!ts.isExternalOrCommonJsModule(location))
                             break;
+                        isInExternalModule = true;
                     case 225:
                         var moduleExports = getSymbolOfNode(location).exports;
                         if (location.kind === 256 || ts.isAmbientModule(location)) {
@@ -13759,6 +13785,12 @@ var ts;
                         checkResolvedBlockScopedVariable(exportOrLocalSymbol, errorLocation);
                     }
                 }
+                if (result && isInExternalModule) {
+                    var decls = result.declarations;
+                    if (decls && decls.length === 1 && decls[0].kind === 228) {
+                        error(errorLocation, ts.Diagnostics.Identifier_0_must_be_imported_from_a_module, name);
+                    }
+                }
             }
             return result;
         }
@@ -15234,7 +15266,7 @@ var ts;
         }
         function getTypeForBindingElementParent(node) {
             var symbol = getSymbolOfNode(node);
-            return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node);
+            return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node, false);
         }
         function getTextOfPropertyName(name) {
             switch (name.kind) {
@@ -15339,7 +15371,7 @@ var ts;
         function addOptionality(type, optional) {
             return strictNullChecks && optional ? addNullableKind(type, 32) : type;
         }
-        function getTypeForVariableLikeDeclaration(declaration) {
+        function getTypeForVariableLikeDeclaration(declaration, includeOptionality) {
             if (declaration.flags & 134217728) {
                 var type = getTypeForVariableLikeDeclarationFromJSDocComment(declaration);
                 if (type && type !== unknownType) {
@@ -15356,7 +15388,7 @@ var ts;
                 return getTypeForBindingElement(declaration);
             }
             if (declaration.type) {
-                return addOptionality(getTypeFromTypeNode(declaration.type), !!declaration.questionToken);
+                return addOptionality(getTypeFromTypeNode(declaration.type), declaration.questionToken && includeOptionality);
             }
             if (declaration.kind === 142) {
                 var func = declaration.parent;
@@ -15375,11 +15407,11 @@ var ts;
                     ? getContextuallyTypedThisType(func)
                     : getContextuallyTypedParameterType(declaration);
                 if (type) {
-                    return addOptionality(type, !!declaration.questionToken);
+                    return addOptionality(type, declaration.questionToken && includeOptionality);
                 }
             }
             if (declaration.initializer) {
-                return addOptionality(checkExpressionCached(declaration.initializer), !!declaration.questionToken);
+                return addOptionality(checkExpressionCached(declaration.initializer), declaration.questionToken && includeOptionality);
             }
             if (declaration.kind === 254) {
                 return checkIdentifier(declaration.name);
@@ -15447,7 +15479,7 @@ var ts;
                 : getTypeFromArrayBindingPattern(pattern, includePatternInType);
         }
         function getWidenedTypeForVariableLikeDeclaration(declaration, reportErrors) {
-            var type = getTypeForVariableLikeDeclaration(declaration);
+            var type = getTypeForVariableLikeDeclaration(declaration, true);
             if (type) {
                 if (reportErrors) {
                     reportErrorsFromWidening(declaration, type);
@@ -17764,7 +17796,7 @@ var ts;
                     return isIdenticalTo(source, target);
                 }
                 if (!(target.flags & 134217728)) {
-                    if (target.flags & 1)
+                    if (target.flags & 1 || source.flags & 134217728)
                         return -1;
                     if (source.flags & 32) {
                         if (!strictNullChecks || target.flags & (32 | 16) || source === emptyArrayElementType)
@@ -17784,7 +17816,7 @@ var ts;
                     if (source.flags & 256 && target === stringType)
                         return -1;
                     if (relation === assignableRelation || relation === comparableRelation) {
-                        if (source.flags & (1 | 134217728))
+                        if (source.flags & 1)
                             return -1;
                         if (source === numberType && target.flags & 128)
                             return -1;
@@ -18561,41 +18593,47 @@ var ts;
                 getSignaturesOfType(type, 0).length === 0 &&
                 getSignaturesOfType(type, 1).length === 0;
         }
+        function createTransientSymbol(source, type) {
+            var symbol = createSymbol(source.flags | 67108864, source.name);
+            symbol.declarations = source.declarations;
+            symbol.parent = source.parent;
+            symbol.type = type;
+            symbol.target = source;
+            if (source.valueDeclaration) {
+                symbol.valueDeclaration = source.valueDeclaration;
+            }
+            return symbol;
+        }
+        function transformTypeOfMembers(type, f) {
+            var members = {};
+            for (var _i = 0, _a = getPropertiesOfObjectType(type); _i < _a.length; _i++) {
+                var property = _a[_i];
+                var original = getTypeOfSymbol(property);
+                var updated = f(original);
+                members[property.name] = updated === original ? property : createTransientSymbol(property, updated);
+            }
+            ;
+            return members;
+        }
         function getRegularTypeOfObjectLiteral(type) {
-            if (type.flags & 1048576) {
-                var regularType = type.regularType;
-                if (!regularType) {
-                    regularType = createType(type.flags & ~1048576);
-                    regularType.symbol = type.symbol;
-                    regularType.members = type.members;
-                    regularType.properties = type.properties;
-                    regularType.callSignatures = type.callSignatures;
-                    regularType.constructSignatures = type.constructSignatures;
-                    regularType.stringIndexInfo = type.stringIndexInfo;
-                    regularType.numberIndexInfo = type.numberIndexInfo;
-                    type.regularType = regularType;
-                }
+            if (!(type.flags & 1048576)) {
+                return type;
+            }
+            var regularType = type.regularType;
+            if (regularType) {
                 return regularType;
             }
-            return type;
+            var resolved = type;
+            var members = transformTypeOfMembers(type, getRegularTypeOfObjectLiteral);
+            var regularNew = createAnonymousType(resolved.symbol, members, resolved.callSignatures, resolved.constructSignatures, resolved.stringIndexInfo, resolved.numberIndexInfo);
+            regularNew.flags = resolved.flags & ~1048576;
+            type.regularType = regularNew;
+            return regularNew;
         }
         function getWidenedTypeOfObjectLiteral(type) {
-            var properties = getPropertiesOfObjectType(type);
-            var members = {};
-            ts.forEach(properties, function (p) {
-                var propType = getTypeOfSymbol(p);
-                var widenedType = getWidenedType(propType);
-                if (propType !== widenedType) {
-                    var symbol = createSymbol(p.flags | 67108864, p.name);
-                    symbol.declarations = p.declarations;
-                    symbol.parent = p.parent;
-                    symbol.type = widenedType;
-                    symbol.target = p;
-                    if (p.valueDeclaration)
-                        symbol.valueDeclaration = p.valueDeclaration;
-                    p = symbol;
-                }
-                members[p.name] = p;
+            var members = transformTypeOfMembers(type, function (prop) {
+                var widened = getWidenedType(prop);
+                return prop === widened ? prop : widened;
             });
             var stringIndexInfo = getIndexInfoOfType(type, 0);
             var numberIndexInfo = getIndexInfoOfType(type, 1);
@@ -19888,7 +19926,7 @@ var ts;
             }
             return nodeCheckFlag === 512
                 ? getBaseConstructorTypeOfClass(classType)
-                : baseClassType;
+                : getTypeWithThisArgument(baseClassType, classType.thisType);
             function isLegalUsageOfSuperExpression(container) {
                 if (!container) {
                     return false;
@@ -21936,7 +21974,7 @@ var ts;
                 var types = void 0;
                 var funcIsGenerator = !!func.asteriskToken;
                 if (funcIsGenerator) {
-                    types = checkAndAggregateYieldOperandTypes(func.body, contextualMapper);
+                    types = checkAndAggregateYieldOperandTypes(func, contextualMapper);
                     if (types.length === 0) {
                         var iterableIteratorAny = createIterableIteratorType(anyType);
                         if (compilerOptions.noImplicitAny) {
@@ -21946,8 +21984,7 @@ var ts;
                     }
                 }
                 else {
-                    var hasImplicitReturn = !!(func.flags & 32768);
-                    types = checkAndAggregateReturnExpressionTypes(func.body, contextualMapper, isAsync, hasImplicitReturn);
+                    types = checkAndAggregateReturnExpressionTypes(func, contextualMapper);
                     if (!types) {
                         return neverType;
                     }
@@ -21994,9 +22031,9 @@ var ts;
                 return widenedType;
             }
         }
-        function checkAndAggregateYieldOperandTypes(body, contextualMapper) {
+        function checkAndAggregateYieldOperandTypes(func, contextualMapper) {
             var aggregatedTypes = [];
-            ts.forEachYieldExpression(body, function (yieldExpression) {
+            ts.forEachYieldExpression(func.body, function (yieldExpression) {
                 var expr = yieldExpression.expression;
                 if (expr) {
                     var type = checkExpressionCached(expr, contextualMapper);
@@ -22010,28 +22047,34 @@ var ts;
             });
             return aggregatedTypes;
         }
-        function checkAndAggregateReturnExpressionTypes(body, contextualMapper, isAsync, hasImplicitReturn) {
+        function checkAndAggregateReturnExpressionTypes(func, contextualMapper) {
+            var isAsync = ts.isAsyncFunctionLike(func);
             var aggregatedTypes = [];
-            var hasOmittedExpressions = false;
-            ts.forEachReturnStatement(body, function (returnStatement) {
+            var hasReturnWithNoExpression = !!(func.flags & 32768);
+            var hasReturnOfTypeNever = false;
+            ts.forEachReturnStatement(func.body, function (returnStatement) {
                 var expr = returnStatement.expression;
                 if (expr) {
                     var type = checkExpressionCached(expr, contextualMapper);
                     if (isAsync) {
-                        type = checkAwaitedType(type, body.parent, ts.Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
+                        type = checkAwaitedType(type, func, ts.Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
                     }
-                    if (type !== neverType && !ts.contains(aggregatedTypes, type)) {
+                    if (type === neverType) {
+                        hasReturnOfTypeNever = true;
+                    }
+                    else if (!ts.contains(aggregatedTypes, type)) {
                         aggregatedTypes.push(type);
                     }
                 }
                 else {
-                    hasOmittedExpressions = true;
+                    hasReturnWithNoExpression = true;
                 }
             });
-            if (aggregatedTypes.length === 0 && !hasOmittedExpressions && !hasImplicitReturn) {
+            if (aggregatedTypes.length === 0 && !hasReturnWithNoExpression && (hasReturnOfTypeNever ||
+                func.kind === 179 || func.kind === 180)) {
                 return undefined;
             }
-            if (strictNullChecks && aggregatedTypes.length && (hasOmittedExpressions || hasImplicitReturn)) {
+            if (strictNullChecks && aggregatedTypes.length && hasReturnWithNoExpression) {
                 if (!ts.contains(aggregatedTypes, undefinedType)) {
                     aggregatedTypes.push(undefinedType);
                 }
@@ -22161,7 +22204,9 @@ var ts;
                     (expr.kind === 172 || expr.kind === 173) &&
                     expr.expression.kind === 97) {
                     var func = ts.getContainingFunction(expr);
-                    return !(func && func.kind === 148 && func.parent === symbol.valueDeclaration.parent);
+                    if (!(func && func.kind === 148))
+                        return true;
+                    return !(func.parent === symbol.valueDeclaration.parent || func === symbol.valueDeclaration.parent);
                 }
                 return true;
             }
@@ -22985,6 +23030,79 @@ var ts;
                 }
             }
         }
+        function checkClassForDuplicateDeclarations(node) {
+            var getter = 1, setter = 2, property = getter | setter;
+            var instanceNames = {};
+            var staticNames = {};
+            for (var _i = 0, _a = node.members; _i < _a.length; _i++) {
+                var member = _a[_i];
+                if (member.kind === 148) {
+                    for (var _b = 0, _c = member.parameters; _b < _c.length; _b++) {
+                        var param = _c[_b];
+                        if (ts.isParameterPropertyDeclaration(param)) {
+                            addName(instanceNames, param.name, param.name.text, property);
+                        }
+                    }
+                }
+                else {
+                    var static = ts.forEach(member.modifiers, function (m) { return m.kind === 113; });
+                    var names = static ? staticNames : instanceNames;
+                    var memberName = member.name && ts.getPropertyNameForPropertyNameNode(member.name);
+                    if (memberName) {
+                        switch (member.kind) {
+                            case 149:
+                                addName(names, member.name, memberName, getter);
+                                break;
+                            case 150:
+                                addName(names, member.name, memberName, setter);
+                                break;
+                            case 145:
+                                addName(names, member.name, memberName, property);
+                                break;
+                        }
+                    }
+                }
+            }
+            function addName(names, location, name, meaning) {
+                if (ts.hasProperty(names, name)) {
+                    var prev = names[name];
+                    if (prev & meaning) {
+                        error(location, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(location));
+                    }
+                    else {
+                        names[name] = prev | meaning;
+                    }
+                }
+                else {
+                    names[name] = meaning;
+                }
+            }
+        }
+        function checkObjectTypeForDuplicateDeclarations(node) {
+            var names = {};
+            for (var _i = 0, _a = node.members; _i < _a.length; _i++) {
+                var member = _a[_i];
+                if (member.kind == 144) {
+                    var memberName = void 0;
+                    switch (member.name.kind) {
+                        case 9:
+                        case 8:
+                        case 69:
+                            memberName = member.name.text;
+                            break;
+                        default:
+                            continue;
+                    }
+                    if (ts.hasProperty(names, memberName)) {
+                        error(member.symbol.valueDeclaration.name, ts.Diagnostics.Duplicate_identifier_0, memberName);
+                        error(member.name, ts.Diagnostics.Duplicate_identifier_0, memberName);
+                    }
+                    else {
+                        names[memberName] = true;
+                    }
+                }
+            }
+        }
         function checkTypeForDuplicateIndexSignatures(node) {
             if (node.kind === 222) {
                 var nodeSymbol = getSymbolOfNode(node);
@@ -23203,6 +23321,7 @@ var ts;
                 var type = getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node);
                 checkIndexConstraints(type);
                 checkTypeForDuplicateIndexSignatures(node);
+                checkObjectTypeForDuplicateDeclarations(node);
             }
         }
         function checkArrayType(node) {
@@ -23962,6 +24081,10 @@ var ts;
                 if (node.initializer) {
                     checkTypeAssignableTo(checkExpressionCached(node.initializer), declarationType, node, undefined);
                 }
+                if (!areDeclarationFlagsIdentical(node, symbol.valueDeclaration)) {
+                    error(symbol.valueDeclaration.name, ts.Diagnostics.All_declarations_of_0_must_have_identical_modifiers, ts.declarationNameToString(node.name));
+                    error(node.name, ts.Diagnostics.All_declarations_of_0_must_have_identical_modifiers, ts.declarationNameToString(node.name));
+                }
             }
             if (node.kind !== 145 && node.kind !== 144) {
                 checkExportsOnMergedDeclarations(node);
@@ -23974,6 +24097,18 @@ var ts;
                 checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name);
             }
         }
+        function areDeclarationFlagsIdentical(left, right) {
+            if (ts.hasQuestionToken(left) !== ts.hasQuestionToken(right)) {
+                return false;
+            }
+            var interestingFlags = 8 |
+                16 |
+                256 |
+                128 |
+                64 |
+                32;
+            return (left.flags & interestingFlags) === (right.flags & interestingFlags);
+        }
         function checkVariableDeclaration(node) {
             checkGrammarVariableDeclaration(node);
             return checkVariableLikeDeclaration(node);
@@ -24524,6 +24659,7 @@ var ts;
             var typeWithThis = getTypeWithThisArgument(type);
             var staticType = getTypeOfSymbol(symbol);
             checkTypeParameterListsIdentical(node, symbol);
+            checkClassForDuplicateDeclarations(node);
             var baseTypeNode = ts.getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
                 var baseTypes = getBaseTypes(type);
@@ -24735,6 +24871,7 @@ var ts;
                         checkIndexConstraints(type);
                     }
                 }
+                checkObjectTypeForDuplicateDeclarations(node);
             }
             ts.forEach(ts.getInterfaceBaseTypeNodes(node), function (heritageElement) {
                 if (!ts.isSupportedExpressionWithTypeArguments(heritageElement)) {
@@ -25489,10 +25626,8 @@ var ts;
         function checkSourceFileWorker(node) {
             var links = getNodeLinks(node);
             if (!(links.flags & 1)) {
-                if (compilerOptions.skipDefaultLibCheck) {
-                    if (node.hasNoDefaultLib) {
-                        return;
-                    }
+                if (compilerOptions.skipLibCheck && node.isDeclarationFile || compilerOptions.skipDefaultLibCheck && node.hasNoDefaultLib) {
+                    return;
                 }
                 checkGrammarSourceFile(node);
                 potentialThisCollisions.length = 0;
@@ -25861,7 +25996,7 @@ var ts;
                 return symbol && getTypeOfSymbol(symbol);
             }
             if (ts.isBindingPattern(node)) {
-                return getTypeForVariableLikeDeclaration(node.parent);
+                return getTypeForVariableLikeDeclaration(node.parent, true);
             }
             if (isInRightSideOfImportOrExportAssignment(node)) {
                 var symbol = getSymbolAtLocation(node);
@@ -26300,7 +26435,7 @@ var ts;
                 if (file.moduleAugmentations.length) {
                     (augmentations || (augmentations = [])).push(file.moduleAugmentations);
                 }
-                if (file.wasReferenced && file.symbol && file.symbol.globalExports) {
+                if (file.symbol && file.symbol.globalExports) {
                     mergeSymbolTable(globals, file.symbol.globalExports);
                 }
             });
@@ -26870,7 +27005,6 @@ var ts;
                 if (prop.kind === 193 ||
                     name_20.kind === 140) {
                     checkGrammarComputedPropertyName(name_20);
-                    return "continue";
                 }
                 if (prop.kind === 254 && !inDestructuring && prop.objectAssignmentInitializer) {
                     return { value: grammarErrorOnNode(prop.equalsToken, ts.Diagnostics.can_only_be_used_in_an_object_literal_property_inside_a_destructuring_assignment) };
@@ -26900,17 +27034,21 @@ var ts;
                 else {
                     ts.Debug.fail("Unexpected syntax kind:" + prop.kind);
                 }
-                if (!ts.hasProperty(seen, name_20.text)) {
-                    seen[name_20.text] = currentKind;
+                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_20);
+                if (effectiveName === undefined) {
+                    return "continue";
+                }
+                if (!ts.hasProperty(seen, effectiveName)) {
+                    seen[effectiveName] = currentKind;
                 }
                 else {
-                    var existingKind = seen[name_20.text];
+                    var existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
-                        return "continue";
+                        grammarErrorOnNode(name_20, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_20));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
-                            seen[name_20.text] = currentKind | existingKind;
+                            seen[effectiveName] = currentKind | existingKind;
                         }
                         else {
                             return { value: grammarErrorOnNode(name_20, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name) };
@@ -35367,7 +35505,7 @@ var ts;
             skipTsx: true,
             traceEnabled: traceEnabled
         };
-        var rootDir = options.typesRoot || (options.configFilePath ? ts.getDirectoryPath(options.configFilePath) : undefined);
+        var rootDir = options.typesRoot || (options.configFilePath ? ts.getDirectoryPath(options.configFilePath) : (host.getCurrentDirectory && host.getCurrentDirectory()));
         if (traceEnabled) {
             if (containingFile === undefined) {
                 if (rootDir === undefined) {
@@ -35870,12 +36008,25 @@ var ts;
                 }
             }
         }
+        function getDefaultTypeDirectiveNames(rootPath) {
+            var localTypes = ts.combinePaths(rootPath, "types");
+            var npmTypes = ts.combinePaths(rootPath, "node_modules/@types");
+            var result = [];
+            if (ts.sys.directoryExists(localTypes)) {
+                result = result.concat(ts.sys.getDirectories(localTypes));
+            }
+            if (ts.sys.directoryExists(npmTypes)) {
+                result = result.concat(ts.sys.getDirectories(npmTypes));
+            }
+            return result;
+        }
         function getDefaultLibLocation() {
             return ts.getDirectoryPath(ts.normalizePath(ts.sys.getExecutingFilePath()));
         }
         var newLine = ts.getNewLineCharacter(options);
         var realpath = ts.sys.realpath && (function (path) { return ts.sys.realpath(path); });
         return {
+            getDefaultTypeDirectiveNames: getDefaultTypeDirectiveNames,
             getSourceFile: getSourceFile,
             getDefaultLibLocation: getDefaultLibLocation,
             getDefaultLibFileName: function (options) { return ts.combinePaths(getDefaultLibLocation(), ts.getDefaultLibFileName(options)); },
@@ -35943,6 +36094,19 @@ var ts;
         }
         return resolutions;
     }
+    function getDefaultTypeDirectiveNames(options, rootFiles, host) {
+        if (options.types) {
+            return options.types;
+        }
+        if (host && host.getDefaultTypeDirectiveNames) {
+            var commonRoot = computeCommonSourceDirectoryOfFilenames(rootFiles, host.getCurrentDirectory(), function (f) { return host.getCanonicalFileName(f); });
+            if (commonRoot) {
+                return host.getDefaultTypeDirectiveNames(commonRoot);
+            }
+        }
+        return undefined;
+    }
+    ts.getDefaultTypeDirectiveNames = getDefaultTypeDirectiveNames;
     function createProgram(rootNames, options, host, oldProgram) {
         var program;
         var files = [];
@@ -35978,13 +36142,14 @@ var ts;
         var filesByName = ts.createFileMap();
         var filesByNameIgnoreCase = host.useCaseSensitiveFileNames() ? ts.createFileMap(function (fileName) { return fileName.toLowerCase(); }) : undefined;
         if (!tryReuseStructureFromOldProgram()) {
-            if (options.types && options.types.length) {
-                var resolutions = resolveTypeReferenceDirectiveNamesWorker(options.types, undefined);
-                for (var i = 0; i < options.types.length; i++) {
-                    processTypeReferenceDirective(options.types[i], resolutions[i]);
+            ts.forEach(rootNames, function (name) { return processRootFile(name, false); });
+            var typeReferences = getDefaultTypeDirectiveNames(options, rootNames, host);
+            if (typeReferences) {
+                var resolutions = resolveTypeReferenceDirectiveNamesWorker(typeReferences, undefined);
+                for (var i = 0; i < typeReferences.length; i++) {
+                    processTypeReferenceDirective(typeReferences[i], resolutions[i]);
                 }
             }
-            ts.forEach(rootNames, function (name) { return processRootFile(name, false); });
             if (!skipDefaultLib) {
                 if (!options.lib) {
                     processRootFile(host.getDefaultLibFileName(options), true);
@@ -36561,9 +36726,6 @@ var ts;
                 if (file_1 && options.forceConsistentCasingInFileNames && ts.getNormalizedAbsolutePath(file_1.fileName, currentDirectory) !== ts.getNormalizedAbsolutePath(fileName, currentDirectory)) {
                     reportFileNamesDifferOnlyInCasingError(fileName, file_1.fileName, refFile, refPos, refEnd);
                 }
-                if (file_1) {
-                    file_1.wasReferenced = file_1.wasReferenced || isReference;
-                }
                 return file_1;
             }
             var file = host.getSourceFile(fileName, options.target, function (hostErrorMessage) {
@@ -36576,7 +36738,6 @@ var ts;
             });
             filesByName.set(path, file);
             if (file) {
-                file.wasReferenced = file.wasReferenced || isReference;
                 file.path = path;
                 if (host.useCaseSensitiveFileNames()) {
                     var existingFile = filesByNameIgnoreCase.get(path);
@@ -36677,17 +36838,7 @@ var ts;
                         !options.noResolve &&
                         i < file.imports.length;
                     if (shouldAddFile) {
-                        var importedFile = findSourceFile(resolution.resolvedFileName, ts.toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName), false, false, file, ts.skipTrivia(file.text, file.imports[i].pos), file.imports[i].end);
-                        if (importedFile && resolution.isExternalLibraryImport) {
-                            if (!ts.isExternalModule(importedFile) && importedFile.statements.length) {
-                                var start_5 = ts.getTokenPosOfNode(file.imports[i], file);
-                                fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_5, file.imports[i].end - start_5, 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 (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));
-                            }
-                        }
+                        findSourceFile(resolution.resolvedFileName, ts.toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName), false, false, file, ts.skipTrivia(file.text, file.imports[i].pos), file.imports[i].end);
                     }
                 }
             }
@@ -36772,7 +36923,7 @@ var ts;
                         }
                     }
                     else {
-                        programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Substututions_for_pattern_0_should_be_an_array, key));
+                        programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Substitutions_for_pattern_0_should_be_an_array, key));
                     }
                 }
             }
@@ -36821,13 +36972,19 @@ var ts;
             }
             else if (firstExternalModuleSourceFile && languageVersion < 2 && options.module === ts.ModuleKind.None) {
                 var span = ts.getErrorSpanForNode(firstExternalModuleSourceFile, firstExternalModuleSourceFile.externalModuleIndicator);
-                programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file));
+                programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_use_imports_exports_or_module_augmentations_when_module_is_none));
             }
             if (options.module === ts.ModuleKind.ES6 && languageVersion < 2) {
                 programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Cannot_compile_modules_into_es2015_when_targeting_ES5_or_lower));
             }
-            if (outFile && options.module && !(options.module === ts.ModuleKind.AMD || options.module === ts.ModuleKind.System)) {
-                programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Only_amd_and_system_modules_are_supported_alongside_0, options.out ? "out" : "outFile"));
+            if (outFile) {
+                if (options.module && !(options.module === ts.ModuleKind.AMD || options.module === ts.ModuleKind.System)) {
+                    programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Only_amd_and_system_modules_are_supported_alongside_0, options.out ? "out" : "outFile"));
+                }
+                else if (options.module === undefined && firstExternalModuleSourceFile) {
+                    var span = ts.getErrorSpanForNode(firstExternalModuleSourceFile, firstExternalModuleSourceFile.externalModuleIndicator);
+                    programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system, options.out ? "out" : "outFile"));
+                }
             }
             if (options.outDir ||
                 options.sourceRoot ||
@@ -37517,7 +37674,7 @@ var ts;
 (function (ts) {
     var NavigateTo;
     (function (NavigateTo) {
-        function getNavigateToItems(program, cancellationToken, searchValue, maxResultCount) {
+        function getNavigateToItems(program, checker, cancellationToken, searchValue, maxResultCount) {
             var patternMatcher = ts.createPatternMatcher(searchValue);
             var rawItems = [];
             var baseSensitivity = { sensitivity: "base" };
@@ -37550,6 +37707,17 @@ var ts;
                     }
                 }
             });
+            rawItems = ts.filter(rawItems, function (item) {
+                var decl = item.declaration;
+                if (decl.kind === 231 || decl.kind === 234 || decl.kind === 229) {
+                    var importer = checker.getSymbolAtLocation(decl.name);
+                    var imported = checker.getAliasedSymbol(importer);
+                    return importer.name !== imported.name;
+                }
+                else {
+                    return true;
+                }
+            });
             rawItems.sort(compareNavigateToItems);
             if (maxResultCount !== undefined) {
                 rawItems = rawItems.slice(0, maxResultCount);
@@ -37892,8 +38060,12 @@ var ts;
                         return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.memberSetAccessorElement);
                     case 153:
                         return createItem(node, "[]", ts.ScriptElementKind.indexSignatureElement);
+                    case 224:
+                        return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.enumElement);
                     case 255:
                         return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.memberVariableElement);
+                    case 222:
+                        return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.interfaceElement);
                     case 151:
                         return createItem(node, "()", ts.ScriptElementKind.callSignatureElement);
                     case 152:
@@ -39263,7 +39435,7 @@ var ts;
             }
         }
         function findRightmostChildNodeWithTokens(children, exclusiveStartPosition) {
-            for (var i = exclusiveStartPosition - 1; i >= 0; --i) {
+            for (var i = exclusiveStartPosition - 1; i >= 0; i--) {
                 if (nodeHasTokens(children[i])) {
                     return children[i];
                 }
@@ -39889,18 +40061,17 @@ var ts;
                 if (!isStarted) {
                     scanner.scan();
                 }
-                var t;
                 var pos = scanner.getStartPos();
                 while (pos < endPos) {
-                    var t_1 = scanner.getToken();
-                    if (!ts.isTrivia(t_1)) {
+                    var t = scanner.getToken();
+                    if (!ts.isTrivia(t)) {
                         break;
                     }
                     scanner.scan();
                     var item = {
                         pos: pos,
                         end: scanner.getStartPos(),
-                        kind: t_1
+                        kind: t
                     };
                     pos = scanner.getStartPos();
                     if (!leadingTrivia) {
@@ -41550,7 +41721,7 @@ var ts;
                 else {
                     parts = [];
                     var startPos = commentRange.pos;
-                    for (var line = startLine; line < endLine; ++line) {
+                    for (var line = startLine; line < endLine; line++) {
                         var endOfLine = ts.getEndLinePosition(line, sourceFile);
                         parts.push({ pos: startPos, end: endOfLine });
                         startPos = ts.getStartPositionOfLine(line + 1, sourceFile);
@@ -41568,7 +41739,7 @@ var ts;
                     startLine++;
                 }
                 var delta = indentation - nonWhitespaceColumnInFirstPart.column;
-                for (var i = startIndex, len = parts.length; i < len; ++i, ++startLine) {
+                for (var i = startIndex, len = parts.length; i < len; i++, startLine++) {
                     var startLinePos_1 = ts.getStartPositionOfLine(startLine, sourceFile);
                     var nonWhitespaceCharacterAndColumn = i === 0
                         ? nonWhitespaceColumnInFirstPart
@@ -41584,7 +41755,7 @@ var ts;
                 }
             }
             function trimTrailingWhitespacesForLines(line1, line2, range) {
-                for (var line = line1; line < line2; ++line) {
+                for (var line = line1; line < line2; line++) {
                     var lineStartPosition = ts.getStartPositionOfLine(line, sourceFile);
                     var lineEndPosition = ts.getEndLinePosition(line, sourceFile);
                     if (range && (ts.isComment(range.kind) || ts.isStringOrRegularExpressionOrTemplateLiteral(range.kind)) && range.pos <= lineEndPosition && range.end > lineEndPosition) {
@@ -41627,7 +41798,6 @@ var ts;
                 }
             }
             function applyRuleEdits(rule, previousRange, previousStartLine, currentRange, currentStartLine) {
-                var between;
                 switch (rule.Operation.Action) {
                     case 1:
                         return;
@@ -41657,14 +41827,6 @@ var ts;
                 }
             }
         }
-        function isSomeBlock(kind) {
-            switch (kind) {
-                case 199:
-                case 226:
-                    return true;
-            }
-            return false;
-        }
         function getOpenTokenForList(node, list) {
             switch (node.kind) {
                 case 148:
@@ -41722,7 +41884,7 @@ var ts;
                     internedTabsIndentation = [];
                 }
                 if (internedTabsIndentation[tabs] === undefined) {
-                    internedTabsIndentation[tabs] = tabString = repeat('\t', tabs);
+                    internedTabsIndentation[tabs] = tabString = repeat("\t", tabs);
                 }
                 else {
                     tabString = internedTabsIndentation[tabs];
@@ -41747,7 +41909,7 @@ var ts;
             }
             function repeat(value, count) {
                 var s = "";
-                for (var i = 0; i < count; ++i) {
+                for (var i = 0; i < count; i++) {
                     s += value;
                 }
                 return s;
@@ -42015,7 +42177,7 @@ var ts;
                 ts.Debug.assert(index >= 0 && index < list.length);
                 var node = list[index];
                 var lineAndCharacter = getStartLineAndCharacterForNode(node, sourceFile);
-                for (var i = index - 1; i >= 0; --i) {
+                for (var i = index - 1; i >= 0; i--) {
                     if (list[i].kind === 24) {
                         continue;
                     }
@@ -42034,7 +42196,7 @@ var ts;
             function findFirstNonWhitespaceCharacterAndColumn(startPos, endPos, sourceFile, options) {
                 var character = 0;
                 var column = 0;
-                for (var pos = startPos; pos < endPos; ++pos) {
+                for (var pos = startPos; pos < endPos; pos++) {
                     var ch = sourceFile.text.charCodeAt(pos);
                     if (!ts.isWhiteSpace(ch)) {
                         break;
@@ -44005,9 +44167,9 @@ 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_6 = new Date().getTime();
+                var start_5 = new Date().getTime();
                 contextToken = ts.findPrecedingToken(contextToken.getFullStart(), sourceFile);
-                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_6));
+                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_5));
             }
             var node = currentToken;
             var isRightOfDot = false;
@@ -44234,9 +44396,9 @@ var ts;
                     || contextToken.kind === 166
                     || contextToken.kind === 10
                     || ts.isTemplateLiteralKind(contextToken.kind)) {
-                    var start_7 = contextToken.getStart();
+                    var start_6 = contextToken.getStart();
                     var end = contextToken.getEnd();
-                    if (start_7 < position && position < end) {
+                    if (start_6 < position && position < end) {
                         return true;
                     }
                     if (position === end) {
@@ -45314,8 +45476,7 @@ var ts;
         }
         function getDocumentHighlights(fileName, position, filesToSearch) {
             synchronizeHostData();
-            filesToSearch = ts.map(filesToSearch, ts.normalizeSlashes);
-            var sourceFilesToSearch = ts.filter(program.getSourceFiles(), function (f) { return ts.contains(filesToSearch, f.fileName); });
+            var sourceFilesToSearch = ts.map(filesToSearch, function (f) { return program.getSourceFile(f); });
             var sourceFile = getValidSourceFile(fileName);
             var node = ts.getTouchingWord(sourceFile, position);
             if (!node) {
@@ -46498,7 +46659,8 @@ var ts;
         }
         function getNavigateToItems(searchValue, maxResultCount) {
             synchronizeHostData();
-            return ts.NavigateTo.getNavigateToItems(program, cancellationToken, searchValue, maxResultCount);
+            var checker = getProgram().getTypeChecker();
+            return ts.NavigateTo.getNavigateToItems(program, checker, cancellationToken, searchValue, maxResultCount);
         }
         function getEmitOutput(fileName) {
             synchronizeHostData();
@@ -51195,6 +51357,9 @@ var ts;
         LanguageServiceShimHostAdapter.prototype.getCurrentDirectory = function () {
             return this.shimHost.getCurrentDirectory();
         };
+        LanguageServiceShimHostAdapter.prototype.getDirectories = function (path) {
+            return this.shimHost.getDirectories(path);
+        };
         LanguageServiceShimHostAdapter.prototype.getDefaultLibFileName = function (options) {
             return this.shimHost.getDefaultLibFileName(JSON.stringify(options));
         };
diff --git a/lib/tsserverlibrary.d.ts b/lib/tsserverlibrary.d.ts
index 0629ad983a3..76b66dda93b 100644
--- a/lib/tsserverlibrary.d.ts
+++ b/lib/tsserverlibrary.d.ts
@@ -247,7 +247,7 @@ declare namespace ts {
         ModuleDeclaration = 225,
         ModuleBlock = 226,
         CaseBlock = 227,
-        GlobalModuleExportDeclaration = 228,
+        NamespaceExportDeclaration = 228,
         ImportEqualsDeclaration = 229,
         ImportDeclaration = 230,
         ImportClause = 231,
@@ -925,7 +925,7 @@ declare namespace ts {
     interface NamespaceImport extends Declaration {
         name: Identifier;
     }
-    interface GlobalModuleExportDeclaration extends DeclarationStatement {
+    interface NamespaceExportDeclaration extends DeclarationStatement {
         name: Identifier;
         moduleReference: LiteralLikeNode;
     }
@@ -1087,7 +1087,6 @@ declare namespace ts {
         scriptKind: ScriptKind;
         externalModuleIndicator: Node;
         commonJsModuleIndicator: Node;
-        wasReferenced?: boolean;
         identifiers: Map<string>;
         nodeCount: number;
         identifierCount: number;
@@ -1381,7 +1380,7 @@ declare namespace ts {
         FunctionScopedVariableExcludes = 107454,
         BlockScopedVariableExcludes = 107455,
         ParameterExcludes = 107455,
-        PropertyExcludes = 107455,
+        PropertyExcludes = 0,
         EnumMemberExcludes = 107455,
         FunctionExcludes = 106927,
         ClassExcludes = 899519,
@@ -1735,6 +1734,7 @@ declare namespace ts {
         allowJs?: boolean;
         noImplicitUseStrict?: boolean;
         strictNullChecks?: boolean;
+        skipLibCheck?: boolean;
         listEmittedFiles?: boolean;
         lib?: string[];
         stripInternal?: boolean;
@@ -1967,6 +1967,7 @@ declare namespace ts {
         trace?(s: string): void;
         directoryExists?(directoryName: string): boolean;
         realpath?(path: string): string;
+        getCurrentDirectory?(): string;
     }
     interface ResolvedModule {
         resolvedFileName: string;
@@ -1990,6 +1991,7 @@ declare namespace ts {
         getCancellationToken?(): CancellationToken;
         getDefaultLibFileName(options: CompilerOptions): string;
         getDefaultLibLocation?(): string;
+        getDefaultTypeDirectiveNames?(rootPath: string): string[];
         writeFile: WriteFileCallback;
         getCurrentDirectory(): string;
         getCanonicalFileName(fileName: string): string;
@@ -2136,6 +2138,7 @@ declare namespace ts {
         createDirectory(path: string): void;
         getExecutingFilePath(): string;
         getCurrentDirectory(): string;
+        getDirectories(path: string): string[];
         readDirectory(path: string, extension?: string, exclude?: string[]): string[];
         getModifiedTime?(path: string): Date;
         createHash?(data: string): string;
@@ -2820,7 +2823,7 @@ declare namespace ts {
             key: string;
             message: string;
         };
-        Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file: {
+        Cannot_use_imports_exports_or_module_augmentations_when_module_is_none: {
             code: number;
             category: DiagnosticCategory;
             key: string;
@@ -5040,6 +5043,18 @@ declare namespace ts {
             key: string;
             message: string;
         };
+        Identifier_0_must_be_imported_from_a_module: {
+            code: number;
+            category: DiagnosticCategory;
+            key: string;
+            message: string;
+        };
+        All_declarations_of_0_must_have_identical_modifiers: {
+            code: number;
+            category: DiagnosticCategory;
+            key: string;
+            message: string;
+        };
         Import_declaration_0_is_using_private_name_1: {
             code: number;
             category: DiagnosticCategory;
@@ -5598,7 +5613,7 @@ declare namespace ts {
             key: string;
             message: string;
         };
-        Substututions_for_pattern_0_should_be_an_array: {
+        Substitutions_for_pattern_0_should_be_an_array: {
             code: number;
             category: DiagnosticCategory;
             key: string;
@@ -5676,6 +5691,12 @@ declare namespace ts {
             key: string;
             message: string;
         };
+        Skip_type_checking_of_declaration_files: {
+            code: number;
+            category: DiagnosticCategory;
+            key: string;
+            message: string;
+        };
         Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015: {
             code: number;
             category: DiagnosticCategory;
@@ -6282,6 +6303,12 @@ declare namespace ts {
             key: string;
             message: string;
         };
+        Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system: {
+            code: number;
+            category: DiagnosticCategory;
+            key: string;
+            message: string;
+        };
         Variable_0_implicitly_has_an_1_type: {
             code: number;
             category: DiagnosticCategory;
@@ -7024,6 +7051,7 @@ declare namespace ts {
     function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost;
     function getPreEmitDiagnostics(program: Program, sourceFile?: SourceFile, cancellationToken?: CancellationToken): Diagnostic[];
     function flattenDiagnosticMessageText(messageText: string | DiagnosticMessageChain, newLine: string): string;
+    function getDefaultTypeDirectiveNames(options: CompilerOptions, rootFiles: string[], host: CompilerHost): string[];
     function createProgram(rootNames: string[], options: CompilerOptions, host?: CompilerHost, oldProgram?: Program): Program;
 }
 declare namespace ts.BreakpointResolver {
@@ -7033,7 +7061,7 @@ declare namespace ts.OutliningElementsCollector {
     function collectElements(sourceFile: SourceFile): OutliningSpan[];
 }
 declare namespace ts.NavigateTo {
-    function getNavigateToItems(program: Program, cancellationToken: CancellationToken, searchValue: string, maxResultCount: number): NavigateToItem[];
+    function getNavigateToItems(program: Program, checker: TypeChecker, cancellationToken: CancellationToken, searchValue: string, maxResultCount: number): NavigateToItem[];
 }
 declare namespace ts.NavigationBar {
     function getNavigationBarItems(sourceFile: SourceFile, compilerOptions: CompilerOptions): ts.NavigationBarItem[];
@@ -7431,7 +7459,7 @@ declare namespace ts.formatting {
     }
 }
 declare namespace ts.formatting {
-    module Shared {
+    namespace Shared {
         interface ITokenAccess {
             GetTokens(): SyntaxKind[];
             Contains(token: SyntaxKind): boolean;
@@ -7516,7 +7544,7 @@ declare namespace ts.formatting {
     function getIndentationString(indentation: number, options: FormatCodeOptions): string;
 }
 declare namespace ts.formatting {
-    module SmartIndenter {
+    namespace SmartIndenter {
         function getIndentation(position: number, sourceFile: SourceFile, options: EditorOptions): number;
         function getIndentationForNode(n: Node, ignoreActualIndentationRange: TextRange, sourceFile: SourceFile, options: FormatCodeOptions): number;
         function childStartsOnTheSameLineWithElseInIfStatement(parent: Node, child: TextRangeWithKind, childStartLine: number, sourceFile: SourceFile): boolean;
@@ -8487,6 +8515,7 @@ declare namespace ts {
         getLocalizedDiagnosticMessages(): string;
         getCancellationToken(): HostCancellationToken;
         getCurrentDirectory(): string;
+        getDirectories(path: string): string[];
         getDefaultLibFileName(options: string): string;
         getNewLine?(): string;
         getProjectVersion?(): string;
@@ -8582,6 +8611,7 @@ declare namespace ts {
         getLocalizedDiagnosticMessages(): any;
         getCancellationToken(): HostCancellationToken;
         getCurrentDirectory(): string;
+        getDirectories(path: string): string[];
         getDefaultLibFileName(options: CompilerOptions): string;
     }
     class CoreServicesShimHostAdapter implements ParseConfigHost, ModuleResolutionHost {
diff --git a/lib/tsserverlibrary.js b/lib/tsserverlibrary.js
index 050d9ca265d..902bfcf610e 100644
--- a/lib/tsserverlibrary.js
+++ b/lib/tsserverlibrary.js
@@ -918,6 +918,10 @@ var ts;
                 }
                 return result.sort();
             }
+            function getDirectories(path) {
+                var folder = fso.GetFolder(path);
+                return getNames(folder.subfolders);
+            }
             function readDirectory(path, extension, exclude) {
                 var result = [];
                 exclude = ts.map(exclude, function (s) { return getCanonicalPath(ts.combinePaths(path, s)); });
@@ -972,6 +976,7 @@ var ts;
                 getCurrentDirectory: function () {
                     return new ActiveXObject("WScript.Shell").CurrentDirectory;
                 },
+                getDirectories: getDirectories,
                 readDirectory: readDirectory,
                 exit: function (exitCode) {
                     try {
@@ -1119,6 +1124,9 @@ var ts;
             function directoryExists(path) {
                 return fileSystemEntryExists(path, 1);
             }
+            function getDirectories(path) {
+                return ts.filter(_fs.readdirSync(path), function (p) { return fileSystemEntryExists(ts.combinePaths(path, p), 1); });
+            }
             function readDirectory(path, extension, exclude) {
                 var result = [];
                 exclude = ts.map(exclude, function (s) { return getCanonicalPath(ts.combinePaths(path, s)); });
@@ -1211,6 +1219,7 @@ var ts;
                 getCurrentDirectory: function () {
                     return process.cwd();
                 },
+                getDirectories: getDirectories,
                 readDirectory: readDirectory,
                 getModifiedTime: function (path) {
                     try {
@@ -1261,6 +1270,7 @@ var ts;
                 createDirectory: ChakraHost.createDirectory,
                 getExecutingFilePath: function () { return ChakraHost.executingFile; },
                 getCurrentDirectory: function () { return ChakraHost.currentDirectory; },
+                getDirectories: ChakraHost.getDirectories,
                 readDirectory: ChakraHost.readDirectory,
                 exit: ChakraHost.quit,
                 realpath: realpath
@@ -1394,7 +1404,7 @@ var ts;
         or_expected: { code: 1144, category: ts.DiagnosticCategory.Error, key: "or_expected_1144", message: "'{' or ';' expected." },
         Declaration_expected: { code: 1146, category: ts.DiagnosticCategory.Error, key: "Declaration_expected_1146", message: "Declaration expected." },
         Import_declarations_in_a_namespace_cannot_reference_a_module: { code: 1147, category: ts.DiagnosticCategory.Error, key: "Import_declarations_in_a_namespace_cannot_reference_a_module_1147", message: "Import declarations in a namespace cannot reference a module." },
-        Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file: { code: 1148, category: ts.DiagnosticCategory.Error, key: "Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting__1148", message: "Cannot compile modules unless the '--module' flag is provided with a valid module type. Consider setting the 'module' compiler option in a 'tsconfig.json' file." },
+        Cannot_use_imports_exports_or_module_augmentations_when_module_is_none: { code: 1148, category: ts.DiagnosticCategory.Error, key: "Cannot_use_imports_exports_or_module_augmentations_when_module_is_none_1148", message: "Cannot use imports, exports, or module augmentations when '--module' is 'none'." },
         File_name_0_differs_from_already_included_file_name_1_only_in_casing: { code: 1149, category: ts.DiagnosticCategory.Error, key: "File_name_0_differs_from_already_included_file_name_1_only_in_casing_1149", message: "File name '{0}' differs from already included file name '{1}' only in casing" },
         new_T_cannot_be_used_to_create_an_array_Use_new_Array_T_instead: { code: 1150, category: ts.DiagnosticCategory.Error, key: "new_T_cannot_be_used_to_create_an_array_Use_new_Array_T_instead_1150", message: "'new T[]' cannot be used to create an array. Use 'new Array<T>()' instead." },
         const_declarations_must_be_initialized: { code: 1155, category: ts.DiagnosticCategory.Error, key: "const_declarations_must_be_initialized_1155", message: "'const' declarations must be initialized" },
@@ -1764,6 +1774,8 @@ var ts;
         this_implicitly_has_type_any_because_it_does_not_have_a_type_annotation: { code: 2683, category: ts.DiagnosticCategory.Error, key: "this_implicitly_has_type_any_because_it_does_not_have_a_type_annotation_2683", message: "'this' implicitly has type 'any' because it does not have a type annotation." },
         The_this_context_of_type_0_is_not_assignable_to_method_s_this_of_type_1: { code: 2684, category: ts.DiagnosticCategory.Error, key: "The_this_context_of_type_0_is_not_assignable_to_method_s_this_of_type_1_2684", message: "The 'this' context of type '{0}' is not assignable to method's 'this' of type '{1}'." },
         The_this_types_of_each_signature_are_incompatible: { code: 2685, category: ts.DiagnosticCategory.Error, key: "The_this_types_of_each_signature_are_incompatible_2685", message: "The 'this' types of each signature are incompatible." },
+        Identifier_0_must_be_imported_from_a_module: { code: 2686, category: ts.DiagnosticCategory.Error, key: "Identifier_0_must_be_imported_from_a_module_2686", message: "Identifier '{0}' must be imported from a module" },
+        All_declarations_of_0_must_have_identical_modifiers: { code: 2687, category: ts.DiagnosticCategory.Error, key: "All_declarations_of_0_must_have_identical_modifiers_2687", message: "All declarations of '{0}' must have identical modifiers." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: ts.DiagnosticCategory.Error, key: "Import_declaration_0_is_using_private_name_1_4000", message: "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_4002", message: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
         Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1: { code: 4004, category: ts.DiagnosticCategory.Error, key: "Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1_4004", message: "Type parameter '{0}' of exported interface has or is using private name '{1}'." },
@@ -1857,7 +1869,7 @@ var ts;
         Option_paths_cannot_be_used_without_specifying_baseUrl_option: { code: 5060, category: ts.DiagnosticCategory.Error, key: "Option_paths_cannot_be_used_without_specifying_baseUrl_option_5060", message: "Option 'paths' cannot be used without specifying '--baseUrl' option." },
         Pattern_0_can_have_at_most_one_Asterisk_character: { code: 5061, category: ts.DiagnosticCategory.Error, key: "Pattern_0_can_have_at_most_one_Asterisk_character_5061", message: "Pattern '{0}' can have at most one '*' character" },
         Substitution_0_in_pattern_1_in_can_have_at_most_one_Asterisk_character: { code: 5062, category: ts.DiagnosticCategory.Error, key: "Substitution_0_in_pattern_1_in_can_have_at_most_one_Asterisk_character_5062", message: "Substitution '{0}' in pattern '{1}' in can have at most one '*' character" },
-        Substututions_for_pattern_0_should_be_an_array: { code: 5063, category: ts.DiagnosticCategory.Error, key: "Substututions_for_pattern_0_should_be_an_array_5063", message: "Substututions for pattern '{0}' should be an array." },
+        Substitutions_for_pattern_0_should_be_an_array: { code: 5063, category: ts.DiagnosticCategory.Error, key: "Substitutions_for_pattern_0_should_be_an_array_5063", message: "Substitutions for pattern '{0}' should be an array." },
         Substitution_0_for_pattern_1_has_incorrect_type_expected_string_got_2: { code: 5064, category: ts.DiagnosticCategory.Error, key: "Substitution_0_for_pattern_1_has_incorrect_type_expected_string_got_2_5064", message: "Substitution '{0}' for pattern '{1}' has incorrect type, expected 'string', got '{2}'." },
         Concatenate_and_emit_output_to_single_file: { code: 6001, category: ts.DiagnosticCategory.Message, key: "Concatenate_and_emit_output_to_single_file_6001", message: "Concatenate and emit output to single file." },
         Generates_corresponding_d_ts_file: { code: 6002, category: ts.DiagnosticCategory.Message, key: "Generates_corresponding_d_ts_file_6002", message: "Generates corresponding '.d.ts' file." },
@@ -1870,6 +1882,7 @@ var ts;
         Do_not_emit_comments_to_output: { code: 6009, category: ts.DiagnosticCategory.Message, key: "Do_not_emit_comments_to_output_6009", message: "Do not emit comments to output." },
         Do_not_emit_outputs: { code: 6010, category: ts.DiagnosticCategory.Message, key: "Do_not_emit_outputs_6010", message: "Do not emit outputs." },
         Allow_default_imports_from_modules_with_no_default_export_This_does_not_affect_code_emit_just_typechecking: { code: 6011, category: ts.DiagnosticCategory.Message, key: "Allow_default_imports_from_modules_with_no_default_export_This_does_not_affect_code_emit_just_typech_6011", message: "Allow default imports from modules with no default export. This does not affect code emit, just typechecking." },
+        Skip_type_checking_of_declaration_files: { code: 6012, category: ts.DiagnosticCategory.Message, key: "Skip_type_checking_of_declaration_files_6012", message: "Skip type checking of declaration files." },
         Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015: { code: 6015, category: ts.DiagnosticCategory.Message, key: "Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015_6015", message: "Specify ECMAScript target version: 'ES3' (default), 'ES5', or 'ES2015'" },
         Specify_module_code_generation_Colon_commonjs_amd_system_umd_or_es2015: { code: 6016, category: ts.DiagnosticCategory.Message, key: "Specify_module_code_generation_Colon_commonjs_amd_system_umd_or_es2015_6016", message: "Specify module code generation: 'commonjs', 'amd', 'system', 'umd' or 'es2015'" },
         Print_this_message: { code: 6017, category: ts.DiagnosticCategory.Message, key: "Print_this_message_6017", message: "Print this message." },
@@ -1971,6 +1984,7 @@ var ts;
         Resolving_type_reference_directive_0_containing_file_not_set_root_directory_not_set: { code: 6128, category: ts.DiagnosticCategory.Message, key: "Resolving_type_reference_directive_0_containing_file_not_set_root_directory_not_set_6128", message: "======== Resolving type reference directive '{0}', containing file not set, root directory not set. ========" },
         The_config_file_0_found_doesn_t_contain_any_source_files: { code: 6129, category: ts.DiagnosticCategory.Error, key: "The_config_file_0_found_doesn_t_contain_any_source_files_6129", message: "The config file '{0}' found doesn't contain any source files." },
         Resolving_real_path_for_0_result_1: { code: 6130, category: ts.DiagnosticCategory.Message, key: "Resolving_real_path_for_0_result_1_6130", message: "Resolving real path for '{0}', result '{1}'" },
+        Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system: { code: 6131, category: ts.DiagnosticCategory.Error, key: "Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system_6131", message: "Cannot compile modules using option '{0}' unless the '--module' flag is 'amd' or 'system'." },
         Variable_0_implicitly_has_an_1_type: { code: 7005, category: ts.DiagnosticCategory.Error, key: "Variable_0_implicitly_has_an_1_type_7005", message: "Variable '{0}' implicitly has an '{1}' type." },
         Parameter_0_implicitly_has_an_1_type: { code: 7006, category: ts.DiagnosticCategory.Error, key: "Parameter_0_implicitly_has_an_1_type_7006", message: "Parameter '{0}' implicitly has an '{1}' type." },
         Member_0_implicitly_has_an_1_type: { code: 7008, category: ts.DiagnosticCategory.Error, key: "Member_0_implicitly_has_an_1_type_7008", message: "Member '{0}' implicitly has an '{1}' type." },
@@ -3537,6 +3551,11 @@ var ts;
             type: "boolean",
             description: ts.Diagnostics.Print_this_message
         },
+        {
+            name: "help",
+            shortName: "?",
+            type: "boolean"
+        },
         {
             name: "init",
             type: "boolean",
@@ -3639,6 +3658,11 @@ var ts;
             name: "skipDefaultLibCheck",
             type: "boolean"
         },
+        {
+            name: "skipLibCheck",
+            type: "boolean",
+            description: ts.Diagnostics.Skip_type_checking_of_declaration_files
+        },
         {
             name: "out",
             type: "string",
@@ -5758,7 +5782,7 @@ var ts;
     }
     ts.isWellKnownSymbolSyntactically = isWellKnownSymbolSyntactically;
     function getPropertyNameForPropertyNameNode(name) {
-        if (name.kind === 69 || name.kind === 9 || name.kind === 8) {
+        if (name.kind === 69 || name.kind === 9 || name.kind === 8 || name.kind === 142) {
             return name.text;
         }
         if (name.kind === 140) {
@@ -12804,10 +12828,10 @@ var ts;
                 case 145:
                 case 144:
                 case 266:
-                    return bindPropertyOrMethodOrAccessor(node, 4 | (node.questionToken ? 536870912 : 0), 107455);
+                    return bindPropertyOrMethodOrAccessor(node, 4 | (node.questionToken ? 536870912 : 0), 0);
                 case 253:
                 case 254:
-                    return bindPropertyOrMethodOrAccessor(node, 4, 107455);
+                    return bindPropertyOrMethodOrAccessor(node, 4, 0);
                 case 255:
                     return bindPropertyOrMethodOrAccessor(node, 8, 107455);
                 case 247:
@@ -12819,7 +12843,7 @@ var ts;
                     return declareSymbolAndAddToSymbolTable(node, 131072, 0);
                 case 147:
                 case 146:
-                    return bindPropertyOrMethodOrAccessor(node, 8192 | (node.questionToken ? 536870912 : 0), ts.isObjectLiteralMethod(node) ? 107455 : 99263);
+                    return bindPropertyOrMethodOrAccessor(node, 8192 | (node.questionToken ? 536870912 : 0), ts.isObjectLiteralMethod(node) ? 0 : 99263);
                 case 220:
                     return bindFunctionDeclaration(node);
                 case 148:
@@ -12862,7 +12886,7 @@ var ts;
                 case 238:
                     return declareSymbolAndAddToSymbolTable(node, 8388608, 8388608);
                 case 228:
-                    return bindGlobalModuleExportDeclaration(node);
+                    return bindNamespaceExportDeclaration(node);
                 case 231:
                     return bindImportClause(node);
                 case 236:
@@ -12898,13 +12922,13 @@ var ts;
                 bindAnonymousDeclaration(node, 8388608, getDeclarationName(node));
             }
             else if (boundExpression.kind === 69 && node.kind === 235) {
-                declareSymbol(container.symbol.exports, container.symbol, node, 8388608, 107455 | 8388608);
+                declareSymbol(container.symbol.exports, container.symbol, node, 8388608, 0 | 8388608);
             }
             else {
-                declareSymbol(container.symbol.exports, container.symbol, node, 4, 107455 | 8388608);
+                declareSymbol(container.symbol.exports, container.symbol, node, 4, 0 | 8388608);
             }
         }
-        function bindGlobalModuleExportDeclaration(node) {
+        function bindNamespaceExportDeclaration(node) {
             if (node.modifiers && node.modifiers.length) {
                 file.bindDiagnostics.push(ts.createDiagnosticForNode(node, ts.Diagnostics.Modifiers_cannot_appear_here));
             }
@@ -12956,7 +12980,7 @@ var ts;
         function bindThisPropertyAssignment(node) {
             if (container.kind === 179 || container.kind === 220) {
                 container.symbol.members = container.symbol.members || {};
-                declareSymbol(container.symbol.members, container.symbol, node, 4, 107455 & ~4);
+                declareSymbol(container.symbol.members, container.symbol, node, 4, 0 & ~4);
             }
         }
         function bindPrototypePropertyAssignment(node) {
@@ -12973,7 +12997,7 @@ var ts;
             if (!funcSymbol.members) {
                 funcSymbol.members = {};
             }
-            declareSymbol(funcSymbol.members, funcSymbol, leftSideOfAssignment, 4, 107455);
+            declareSymbol(funcSymbol.members, funcSymbol, leftSideOfAssignment, 4, 0);
         }
         function bindCallExpression(node) {
             if (!file.commonJsModuleIndicator && ts.isRequireCall(node, false)) {
@@ -13049,7 +13073,7 @@ var ts;
             }
             if (ts.isParameterPropertyDeclaration(node)) {
                 var classDeclaration = node.parent.parent;
-                declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, 4, 107455);
+                declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, 4, 0);
             }
         }
         function bindFunctionDeclaration(node) {
@@ -13349,7 +13373,7 @@ var ts;
             if (flags & 1)
                 result |= 107454;
             if (flags & 4)
-                result |= 107455;
+                result |= 0;
             if (flags & 8)
                 result |= 107455;
             if (flags & 16)
@@ -13605,6 +13629,7 @@ var ts;
             var propertyWithInvalidInitializer;
             var errorLocation = location;
             var grandparent;
+            var isInExternalModule = false;
             loop: while (location) {
                 if (location.locals && !isGlobalSourceFile(location)) {
                     if (result = getSymbol(location.locals, name, meaning)) {
@@ -13636,6 +13661,7 @@ var ts;
                     case 256:
                         if (!ts.isExternalOrCommonJsModule(location))
                             break;
+                        isInExternalModule = true;
                     case 225:
                         var moduleExports = getSymbolOfNode(location).exports;
                         if (location.kind === 256 || ts.isAmbientModule(location)) {
@@ -13759,6 +13785,12 @@ var ts;
                         checkResolvedBlockScopedVariable(exportOrLocalSymbol, errorLocation);
                     }
                 }
+                if (result && isInExternalModule) {
+                    var decls = result.declarations;
+                    if (decls && decls.length === 1 && decls[0].kind === 228) {
+                        error(errorLocation, ts.Diagnostics.Identifier_0_must_be_imported_from_a_module, name);
+                    }
+                }
             }
             return result;
         }
@@ -15234,7 +15266,7 @@ var ts;
         }
         function getTypeForBindingElementParent(node) {
             var symbol = getSymbolOfNode(node);
-            return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node);
+            return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node, false);
         }
         function getTextOfPropertyName(name) {
             switch (name.kind) {
@@ -15339,7 +15371,7 @@ var ts;
         function addOptionality(type, optional) {
             return strictNullChecks && optional ? addNullableKind(type, 32) : type;
         }
-        function getTypeForVariableLikeDeclaration(declaration) {
+        function getTypeForVariableLikeDeclaration(declaration, includeOptionality) {
             if (declaration.flags & 134217728) {
                 var type = getTypeForVariableLikeDeclarationFromJSDocComment(declaration);
                 if (type && type !== unknownType) {
@@ -15356,7 +15388,7 @@ var ts;
                 return getTypeForBindingElement(declaration);
             }
             if (declaration.type) {
-                return addOptionality(getTypeFromTypeNode(declaration.type), !!declaration.questionToken);
+                return addOptionality(getTypeFromTypeNode(declaration.type), declaration.questionToken && includeOptionality);
             }
             if (declaration.kind === 142) {
                 var func = declaration.parent;
@@ -15375,11 +15407,11 @@ var ts;
                     ? getContextuallyTypedThisType(func)
                     : getContextuallyTypedParameterType(declaration);
                 if (type) {
-                    return addOptionality(type, !!declaration.questionToken);
+                    return addOptionality(type, declaration.questionToken && includeOptionality);
                 }
             }
             if (declaration.initializer) {
-                return addOptionality(checkExpressionCached(declaration.initializer), !!declaration.questionToken);
+                return addOptionality(checkExpressionCached(declaration.initializer), declaration.questionToken && includeOptionality);
             }
             if (declaration.kind === 254) {
                 return checkIdentifier(declaration.name);
@@ -15447,7 +15479,7 @@ var ts;
                 : getTypeFromArrayBindingPattern(pattern, includePatternInType);
         }
         function getWidenedTypeForVariableLikeDeclaration(declaration, reportErrors) {
-            var type = getTypeForVariableLikeDeclaration(declaration);
+            var type = getTypeForVariableLikeDeclaration(declaration, true);
             if (type) {
                 if (reportErrors) {
                     reportErrorsFromWidening(declaration, type);
@@ -17764,7 +17796,7 @@ var ts;
                     return isIdenticalTo(source, target);
                 }
                 if (!(target.flags & 134217728)) {
-                    if (target.flags & 1)
+                    if (target.flags & 1 || source.flags & 134217728)
                         return -1;
                     if (source.flags & 32) {
                         if (!strictNullChecks || target.flags & (32 | 16) || source === emptyArrayElementType)
@@ -17784,7 +17816,7 @@ var ts;
                     if (source.flags & 256 && target === stringType)
                         return -1;
                     if (relation === assignableRelation || relation === comparableRelation) {
-                        if (source.flags & (1 | 134217728))
+                        if (source.flags & 1)
                             return -1;
                         if (source === numberType && target.flags & 128)
                             return -1;
@@ -18561,41 +18593,47 @@ var ts;
                 getSignaturesOfType(type, 0).length === 0 &&
                 getSignaturesOfType(type, 1).length === 0;
         }
+        function createTransientSymbol(source, type) {
+            var symbol = createSymbol(source.flags | 67108864, source.name);
+            symbol.declarations = source.declarations;
+            symbol.parent = source.parent;
+            symbol.type = type;
+            symbol.target = source;
+            if (source.valueDeclaration) {
+                symbol.valueDeclaration = source.valueDeclaration;
+            }
+            return symbol;
+        }
+        function transformTypeOfMembers(type, f) {
+            var members = {};
+            for (var _i = 0, _a = getPropertiesOfObjectType(type); _i < _a.length; _i++) {
+                var property = _a[_i];
+                var original = getTypeOfSymbol(property);
+                var updated = f(original);
+                members[property.name] = updated === original ? property : createTransientSymbol(property, updated);
+            }
+            ;
+            return members;
+        }
         function getRegularTypeOfObjectLiteral(type) {
-            if (type.flags & 1048576) {
-                var regularType = type.regularType;
-                if (!regularType) {
-                    regularType = createType(type.flags & ~1048576);
-                    regularType.symbol = type.symbol;
-                    regularType.members = type.members;
-                    regularType.properties = type.properties;
-                    regularType.callSignatures = type.callSignatures;
-                    regularType.constructSignatures = type.constructSignatures;
-                    regularType.stringIndexInfo = type.stringIndexInfo;
-                    regularType.numberIndexInfo = type.numberIndexInfo;
-                    type.regularType = regularType;
-                }
+            if (!(type.flags & 1048576)) {
+                return type;
+            }
+            var regularType = type.regularType;
+            if (regularType) {
                 return regularType;
             }
-            return type;
+            var resolved = type;
+            var members = transformTypeOfMembers(type, getRegularTypeOfObjectLiteral);
+            var regularNew = createAnonymousType(resolved.symbol, members, resolved.callSignatures, resolved.constructSignatures, resolved.stringIndexInfo, resolved.numberIndexInfo);
+            regularNew.flags = resolved.flags & ~1048576;
+            type.regularType = regularNew;
+            return regularNew;
         }
         function getWidenedTypeOfObjectLiteral(type) {
-            var properties = getPropertiesOfObjectType(type);
-            var members = {};
-            ts.forEach(properties, function (p) {
-                var propType = getTypeOfSymbol(p);
-                var widenedType = getWidenedType(propType);
-                if (propType !== widenedType) {
-                    var symbol = createSymbol(p.flags | 67108864, p.name);
-                    symbol.declarations = p.declarations;
-                    symbol.parent = p.parent;
-                    symbol.type = widenedType;
-                    symbol.target = p;
-                    if (p.valueDeclaration)
-                        symbol.valueDeclaration = p.valueDeclaration;
-                    p = symbol;
-                }
-                members[p.name] = p;
+            var members = transformTypeOfMembers(type, function (prop) {
+                var widened = getWidenedType(prop);
+                return prop === widened ? prop : widened;
             });
             var stringIndexInfo = getIndexInfoOfType(type, 0);
             var numberIndexInfo = getIndexInfoOfType(type, 1);
@@ -19888,7 +19926,7 @@ var ts;
             }
             return nodeCheckFlag === 512
                 ? getBaseConstructorTypeOfClass(classType)
-                : baseClassType;
+                : getTypeWithThisArgument(baseClassType, classType.thisType);
             function isLegalUsageOfSuperExpression(container) {
                 if (!container) {
                     return false;
@@ -21936,7 +21974,7 @@ var ts;
                 var types = void 0;
                 var funcIsGenerator = !!func.asteriskToken;
                 if (funcIsGenerator) {
-                    types = checkAndAggregateYieldOperandTypes(func.body, contextualMapper);
+                    types = checkAndAggregateYieldOperandTypes(func, contextualMapper);
                     if (types.length === 0) {
                         var iterableIteratorAny = createIterableIteratorType(anyType);
                         if (compilerOptions.noImplicitAny) {
@@ -21946,8 +21984,7 @@ var ts;
                     }
                 }
                 else {
-                    var hasImplicitReturn = !!(func.flags & 32768);
-                    types = checkAndAggregateReturnExpressionTypes(func.body, contextualMapper, isAsync, hasImplicitReturn);
+                    types = checkAndAggregateReturnExpressionTypes(func, contextualMapper);
                     if (!types) {
                         return neverType;
                     }
@@ -21994,9 +22031,9 @@ var ts;
                 return widenedType;
             }
         }
-        function checkAndAggregateYieldOperandTypes(body, contextualMapper) {
+        function checkAndAggregateYieldOperandTypes(func, contextualMapper) {
             var aggregatedTypes = [];
-            ts.forEachYieldExpression(body, function (yieldExpression) {
+            ts.forEachYieldExpression(func.body, function (yieldExpression) {
                 var expr = yieldExpression.expression;
                 if (expr) {
                     var type = checkExpressionCached(expr, contextualMapper);
@@ -22010,28 +22047,34 @@ var ts;
             });
             return aggregatedTypes;
         }
-        function checkAndAggregateReturnExpressionTypes(body, contextualMapper, isAsync, hasImplicitReturn) {
+        function checkAndAggregateReturnExpressionTypes(func, contextualMapper) {
+            var isAsync = ts.isAsyncFunctionLike(func);
             var aggregatedTypes = [];
-            var hasOmittedExpressions = false;
-            ts.forEachReturnStatement(body, function (returnStatement) {
+            var hasReturnWithNoExpression = !!(func.flags & 32768);
+            var hasReturnOfTypeNever = false;
+            ts.forEachReturnStatement(func.body, function (returnStatement) {
                 var expr = returnStatement.expression;
                 if (expr) {
                     var type = checkExpressionCached(expr, contextualMapper);
                     if (isAsync) {
-                        type = checkAwaitedType(type, body.parent, ts.Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
+                        type = checkAwaitedType(type, func, ts.Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
                     }
-                    if (type !== neverType && !ts.contains(aggregatedTypes, type)) {
+                    if (type === neverType) {
+                        hasReturnOfTypeNever = true;
+                    }
+                    else if (!ts.contains(aggregatedTypes, type)) {
                         aggregatedTypes.push(type);
                     }
                 }
                 else {
-                    hasOmittedExpressions = true;
+                    hasReturnWithNoExpression = true;
                 }
             });
-            if (aggregatedTypes.length === 0 && !hasOmittedExpressions && !hasImplicitReturn) {
+            if (aggregatedTypes.length === 0 && !hasReturnWithNoExpression && (hasReturnOfTypeNever ||
+                func.kind === 179 || func.kind === 180)) {
                 return undefined;
             }
-            if (strictNullChecks && aggregatedTypes.length && (hasOmittedExpressions || hasImplicitReturn)) {
+            if (strictNullChecks && aggregatedTypes.length && hasReturnWithNoExpression) {
                 if (!ts.contains(aggregatedTypes, undefinedType)) {
                     aggregatedTypes.push(undefinedType);
                 }
@@ -22161,7 +22204,9 @@ var ts;
                     (expr.kind === 172 || expr.kind === 173) &&
                     expr.expression.kind === 97) {
                     var func = ts.getContainingFunction(expr);
-                    return !(func && func.kind === 148 && func.parent === symbol.valueDeclaration.parent);
+                    if (!(func && func.kind === 148))
+                        return true;
+                    return !(func.parent === symbol.valueDeclaration.parent || func === symbol.valueDeclaration.parent);
                 }
                 return true;
             }
@@ -22985,6 +23030,79 @@ var ts;
                 }
             }
         }
+        function checkClassForDuplicateDeclarations(node) {
+            var getter = 1, setter = 2, property = getter | setter;
+            var instanceNames = {};
+            var staticNames = {};
+            for (var _i = 0, _a = node.members; _i < _a.length; _i++) {
+                var member = _a[_i];
+                if (member.kind === 148) {
+                    for (var _b = 0, _c = member.parameters; _b < _c.length; _b++) {
+                        var param = _c[_b];
+                        if (ts.isParameterPropertyDeclaration(param)) {
+                            addName(instanceNames, param.name, param.name.text, property);
+                        }
+                    }
+                }
+                else {
+                    var static = ts.forEach(member.modifiers, function (m) { return m.kind === 113; });
+                    var names = static ? staticNames : instanceNames;
+                    var memberName = member.name && ts.getPropertyNameForPropertyNameNode(member.name);
+                    if (memberName) {
+                        switch (member.kind) {
+                            case 149:
+                                addName(names, member.name, memberName, getter);
+                                break;
+                            case 150:
+                                addName(names, member.name, memberName, setter);
+                                break;
+                            case 145:
+                                addName(names, member.name, memberName, property);
+                                break;
+                        }
+                    }
+                }
+            }
+            function addName(names, location, name, meaning) {
+                if (ts.hasProperty(names, name)) {
+                    var prev = names[name];
+                    if (prev & meaning) {
+                        error(location, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(location));
+                    }
+                    else {
+                        names[name] = prev | meaning;
+                    }
+                }
+                else {
+                    names[name] = meaning;
+                }
+            }
+        }
+        function checkObjectTypeForDuplicateDeclarations(node) {
+            var names = {};
+            for (var _i = 0, _a = node.members; _i < _a.length; _i++) {
+                var member = _a[_i];
+                if (member.kind == 144) {
+                    var memberName = void 0;
+                    switch (member.name.kind) {
+                        case 9:
+                        case 8:
+                        case 69:
+                            memberName = member.name.text;
+                            break;
+                        default:
+                            continue;
+                    }
+                    if (ts.hasProperty(names, memberName)) {
+                        error(member.symbol.valueDeclaration.name, ts.Diagnostics.Duplicate_identifier_0, memberName);
+                        error(member.name, ts.Diagnostics.Duplicate_identifier_0, memberName);
+                    }
+                    else {
+                        names[memberName] = true;
+                    }
+                }
+            }
+        }
         function checkTypeForDuplicateIndexSignatures(node) {
             if (node.kind === 222) {
                 var nodeSymbol = getSymbolOfNode(node);
@@ -23203,6 +23321,7 @@ var ts;
                 var type = getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node);
                 checkIndexConstraints(type);
                 checkTypeForDuplicateIndexSignatures(node);
+                checkObjectTypeForDuplicateDeclarations(node);
             }
         }
         function checkArrayType(node) {
@@ -23962,6 +24081,10 @@ var ts;
                 if (node.initializer) {
                     checkTypeAssignableTo(checkExpressionCached(node.initializer), declarationType, node, undefined);
                 }
+                if (!areDeclarationFlagsIdentical(node, symbol.valueDeclaration)) {
+                    error(symbol.valueDeclaration.name, ts.Diagnostics.All_declarations_of_0_must_have_identical_modifiers, ts.declarationNameToString(node.name));
+                    error(node.name, ts.Diagnostics.All_declarations_of_0_must_have_identical_modifiers, ts.declarationNameToString(node.name));
+                }
             }
             if (node.kind !== 145 && node.kind !== 144) {
                 checkExportsOnMergedDeclarations(node);
@@ -23974,6 +24097,18 @@ var ts;
                 checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name);
             }
         }
+        function areDeclarationFlagsIdentical(left, right) {
+            if (ts.hasQuestionToken(left) !== ts.hasQuestionToken(right)) {
+                return false;
+            }
+            var interestingFlags = 8 |
+                16 |
+                256 |
+                128 |
+                64 |
+                32;
+            return (left.flags & interestingFlags) === (right.flags & interestingFlags);
+        }
         function checkVariableDeclaration(node) {
             checkGrammarVariableDeclaration(node);
             return checkVariableLikeDeclaration(node);
@@ -24524,6 +24659,7 @@ var ts;
             var typeWithThis = getTypeWithThisArgument(type);
             var staticType = getTypeOfSymbol(symbol);
             checkTypeParameterListsIdentical(node, symbol);
+            checkClassForDuplicateDeclarations(node);
             var baseTypeNode = ts.getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
                 var baseTypes = getBaseTypes(type);
@@ -24735,6 +24871,7 @@ var ts;
                         checkIndexConstraints(type);
                     }
                 }
+                checkObjectTypeForDuplicateDeclarations(node);
             }
             ts.forEach(ts.getInterfaceBaseTypeNodes(node), function (heritageElement) {
                 if (!ts.isSupportedExpressionWithTypeArguments(heritageElement)) {
@@ -25489,10 +25626,8 @@ var ts;
         function checkSourceFileWorker(node) {
             var links = getNodeLinks(node);
             if (!(links.flags & 1)) {
-                if (compilerOptions.skipDefaultLibCheck) {
-                    if (node.hasNoDefaultLib) {
-                        return;
-                    }
+                if (compilerOptions.skipLibCheck && node.isDeclarationFile || compilerOptions.skipDefaultLibCheck && node.hasNoDefaultLib) {
+                    return;
                 }
                 checkGrammarSourceFile(node);
                 potentialThisCollisions.length = 0;
@@ -25861,7 +25996,7 @@ var ts;
                 return symbol && getTypeOfSymbol(symbol);
             }
             if (ts.isBindingPattern(node)) {
-                return getTypeForVariableLikeDeclaration(node.parent);
+                return getTypeForVariableLikeDeclaration(node.parent, true);
             }
             if (isInRightSideOfImportOrExportAssignment(node)) {
                 var symbol = getSymbolAtLocation(node);
@@ -26300,7 +26435,7 @@ var ts;
                 if (file.moduleAugmentations.length) {
                     (augmentations || (augmentations = [])).push(file.moduleAugmentations);
                 }
-                if (file.wasReferenced && file.symbol && file.symbol.globalExports) {
+                if (file.symbol && file.symbol.globalExports) {
                     mergeSymbolTable(globals, file.symbol.globalExports);
                 }
             });
@@ -26870,7 +27005,6 @@ var ts;
                 if (prop.kind === 193 ||
                     name_20.kind === 140) {
                     checkGrammarComputedPropertyName(name_20);
-                    return "continue";
                 }
                 if (prop.kind === 254 && !inDestructuring && prop.objectAssignmentInitializer) {
                     return { value: grammarErrorOnNode(prop.equalsToken, ts.Diagnostics.can_only_be_used_in_an_object_literal_property_inside_a_destructuring_assignment) };
@@ -26900,17 +27034,21 @@ var ts;
                 else {
                     ts.Debug.fail("Unexpected syntax kind:" + prop.kind);
                 }
-                if (!ts.hasProperty(seen, name_20.text)) {
-                    seen[name_20.text] = currentKind;
+                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_20);
+                if (effectiveName === undefined) {
+                    return "continue";
+                }
+                if (!ts.hasProperty(seen, effectiveName)) {
+                    seen[effectiveName] = currentKind;
                 }
                 else {
-                    var existingKind = seen[name_20.text];
+                    var existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
-                        return "continue";
+                        grammarErrorOnNode(name_20, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_20));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
-                            seen[name_20.text] = currentKind | existingKind;
+                            seen[effectiveName] = currentKind | existingKind;
                         }
                         else {
                             return { value: grammarErrorOnNode(name_20, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name) };
@@ -35367,7 +35505,7 @@ var ts;
             skipTsx: true,
             traceEnabled: traceEnabled
         };
-        var rootDir = options.typesRoot || (options.configFilePath ? ts.getDirectoryPath(options.configFilePath) : undefined);
+        var rootDir = options.typesRoot || (options.configFilePath ? ts.getDirectoryPath(options.configFilePath) : (host.getCurrentDirectory && host.getCurrentDirectory()));
         if (traceEnabled) {
             if (containingFile === undefined) {
                 if (rootDir === undefined) {
@@ -35870,12 +36008,25 @@ var ts;
                 }
             }
         }
+        function getDefaultTypeDirectiveNames(rootPath) {
+            var localTypes = ts.combinePaths(rootPath, "types");
+            var npmTypes = ts.combinePaths(rootPath, "node_modules/@types");
+            var result = [];
+            if (ts.sys.directoryExists(localTypes)) {
+                result = result.concat(ts.sys.getDirectories(localTypes));
+            }
+            if (ts.sys.directoryExists(npmTypes)) {
+                result = result.concat(ts.sys.getDirectories(npmTypes));
+            }
+            return result;
+        }
         function getDefaultLibLocation() {
             return ts.getDirectoryPath(ts.normalizePath(ts.sys.getExecutingFilePath()));
         }
         var newLine = ts.getNewLineCharacter(options);
         var realpath = ts.sys.realpath && (function (path) { return ts.sys.realpath(path); });
         return {
+            getDefaultTypeDirectiveNames: getDefaultTypeDirectiveNames,
             getSourceFile: getSourceFile,
             getDefaultLibLocation: getDefaultLibLocation,
             getDefaultLibFileName: function (options) { return ts.combinePaths(getDefaultLibLocation(), ts.getDefaultLibFileName(options)); },
@@ -35943,6 +36094,19 @@ var ts;
         }
         return resolutions;
     }
+    function getDefaultTypeDirectiveNames(options, rootFiles, host) {
+        if (options.types) {
+            return options.types;
+        }
+        if (host && host.getDefaultTypeDirectiveNames) {
+            var commonRoot = computeCommonSourceDirectoryOfFilenames(rootFiles, host.getCurrentDirectory(), function (f) { return host.getCanonicalFileName(f); });
+            if (commonRoot) {
+                return host.getDefaultTypeDirectiveNames(commonRoot);
+            }
+        }
+        return undefined;
+    }
+    ts.getDefaultTypeDirectiveNames = getDefaultTypeDirectiveNames;
     function createProgram(rootNames, options, host, oldProgram) {
         var program;
         var files = [];
@@ -35978,13 +36142,14 @@ var ts;
         var filesByName = ts.createFileMap();
         var filesByNameIgnoreCase = host.useCaseSensitiveFileNames() ? ts.createFileMap(function (fileName) { return fileName.toLowerCase(); }) : undefined;
         if (!tryReuseStructureFromOldProgram()) {
-            if (options.types && options.types.length) {
-                var resolutions = resolveTypeReferenceDirectiveNamesWorker(options.types, undefined);
-                for (var i = 0; i < options.types.length; i++) {
-                    processTypeReferenceDirective(options.types[i], resolutions[i]);
+            ts.forEach(rootNames, function (name) { return processRootFile(name, false); });
+            var typeReferences = getDefaultTypeDirectiveNames(options, rootNames, host);
+            if (typeReferences) {
+                var resolutions = resolveTypeReferenceDirectiveNamesWorker(typeReferences, undefined);
+                for (var i = 0; i < typeReferences.length; i++) {
+                    processTypeReferenceDirective(typeReferences[i], resolutions[i]);
                 }
             }
-            ts.forEach(rootNames, function (name) { return processRootFile(name, false); });
             if (!skipDefaultLib) {
                 if (!options.lib) {
                     processRootFile(host.getDefaultLibFileName(options), true);
@@ -36561,9 +36726,6 @@ var ts;
                 if (file_1 && options.forceConsistentCasingInFileNames && ts.getNormalizedAbsolutePath(file_1.fileName, currentDirectory) !== ts.getNormalizedAbsolutePath(fileName, currentDirectory)) {
                     reportFileNamesDifferOnlyInCasingError(fileName, file_1.fileName, refFile, refPos, refEnd);
                 }
-                if (file_1) {
-                    file_1.wasReferenced = file_1.wasReferenced || isReference;
-                }
                 return file_1;
             }
             var file = host.getSourceFile(fileName, options.target, function (hostErrorMessage) {
@@ -36576,7 +36738,6 @@ var ts;
             });
             filesByName.set(path, file);
             if (file) {
-                file.wasReferenced = file.wasReferenced || isReference;
                 file.path = path;
                 if (host.useCaseSensitiveFileNames()) {
                     var existingFile = filesByNameIgnoreCase.get(path);
@@ -36677,17 +36838,7 @@ var ts;
                         !options.noResolve &&
                         i < file.imports.length;
                     if (shouldAddFile) {
-                        var importedFile = findSourceFile(resolution.resolvedFileName, ts.toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName), false, false, file, ts.skipTrivia(file.text, file.imports[i].pos), file.imports[i].end);
-                        if (importedFile && resolution.isExternalLibraryImport) {
-                            if (!ts.isExternalModule(importedFile) && importedFile.statements.length) {
-                                var start_5 = ts.getTokenPosOfNode(file.imports[i], file);
-                                fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_5, file.imports[i].end - start_5, 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 (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));
-                            }
-                        }
+                        findSourceFile(resolution.resolvedFileName, ts.toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName), false, false, file, ts.skipTrivia(file.text, file.imports[i].pos), file.imports[i].end);
                     }
                 }
             }
@@ -36772,7 +36923,7 @@ var ts;
                         }
                     }
                     else {
-                        programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Substututions_for_pattern_0_should_be_an_array, key));
+                        programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Substitutions_for_pattern_0_should_be_an_array, key));
                     }
                 }
             }
@@ -36821,13 +36972,19 @@ var ts;
             }
             else if (firstExternalModuleSourceFile && languageVersion < 2 && options.module === ts.ModuleKind.None) {
                 var span = ts.getErrorSpanForNode(firstExternalModuleSourceFile, firstExternalModuleSourceFile.externalModuleIndicator);
-                programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file));
+                programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_use_imports_exports_or_module_augmentations_when_module_is_none));
             }
             if (options.module === ts.ModuleKind.ES6 && languageVersion < 2) {
                 programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Cannot_compile_modules_into_es2015_when_targeting_ES5_or_lower));
             }
-            if (outFile && options.module && !(options.module === ts.ModuleKind.AMD || options.module === ts.ModuleKind.System)) {
-                programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Only_amd_and_system_modules_are_supported_alongside_0, options.out ? "out" : "outFile"));
+            if (outFile) {
+                if (options.module && !(options.module === ts.ModuleKind.AMD || options.module === ts.ModuleKind.System)) {
+                    programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Only_amd_and_system_modules_are_supported_alongside_0, options.out ? "out" : "outFile"));
+                }
+                else if (options.module === undefined && firstExternalModuleSourceFile) {
+                    var span = ts.getErrorSpanForNode(firstExternalModuleSourceFile, firstExternalModuleSourceFile.externalModuleIndicator);
+                    programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system, options.out ? "out" : "outFile"));
+                }
             }
             if (options.outDir ||
                 options.sourceRoot ||
@@ -37517,7 +37674,7 @@ var ts;
 (function (ts) {
     var NavigateTo;
     (function (NavigateTo) {
-        function getNavigateToItems(program, cancellationToken, searchValue, maxResultCount) {
+        function getNavigateToItems(program, checker, cancellationToken, searchValue, maxResultCount) {
             var patternMatcher = ts.createPatternMatcher(searchValue);
             var rawItems = [];
             var baseSensitivity = { sensitivity: "base" };
@@ -37550,6 +37707,17 @@ var ts;
                     }
                 }
             });
+            rawItems = ts.filter(rawItems, function (item) {
+                var decl = item.declaration;
+                if (decl.kind === 231 || decl.kind === 234 || decl.kind === 229) {
+                    var importer = checker.getSymbolAtLocation(decl.name);
+                    var imported = checker.getAliasedSymbol(importer);
+                    return importer.name !== imported.name;
+                }
+                else {
+                    return true;
+                }
+            });
             rawItems.sort(compareNavigateToItems);
             if (maxResultCount !== undefined) {
                 rawItems = rawItems.slice(0, maxResultCount);
@@ -37892,8 +38060,12 @@ var ts;
                         return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.memberSetAccessorElement);
                     case 153:
                         return createItem(node, "[]", ts.ScriptElementKind.indexSignatureElement);
+                    case 224:
+                        return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.enumElement);
                     case 255:
                         return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.memberVariableElement);
+                    case 222:
+                        return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.interfaceElement);
                     case 151:
                         return createItem(node, "()", ts.ScriptElementKind.callSignatureElement);
                     case 152:
@@ -39263,7 +39435,7 @@ var ts;
             }
         }
         function findRightmostChildNodeWithTokens(children, exclusiveStartPosition) {
-            for (var i = exclusiveStartPosition - 1; i >= 0; --i) {
+            for (var i = exclusiveStartPosition - 1; i >= 0; i--) {
                 if (nodeHasTokens(children[i])) {
                     return children[i];
                 }
@@ -39889,18 +40061,17 @@ var ts;
                 if (!isStarted) {
                     scanner.scan();
                 }
-                var t;
                 var pos = scanner.getStartPos();
                 while (pos < endPos) {
-                    var t_1 = scanner.getToken();
-                    if (!ts.isTrivia(t_1)) {
+                    var t = scanner.getToken();
+                    if (!ts.isTrivia(t)) {
                         break;
                     }
                     scanner.scan();
                     var item = {
                         pos: pos,
                         end: scanner.getStartPos(),
-                        kind: t_1
+                        kind: t
                     };
                     pos = scanner.getStartPos();
                     if (!leadingTrivia) {
@@ -41550,7 +41721,7 @@ var ts;
                 else {
                     parts = [];
                     var startPos = commentRange.pos;
-                    for (var line = startLine; line < endLine; ++line) {
+                    for (var line = startLine; line < endLine; line++) {
                         var endOfLine = ts.getEndLinePosition(line, sourceFile);
                         parts.push({ pos: startPos, end: endOfLine });
                         startPos = ts.getStartPositionOfLine(line + 1, sourceFile);
@@ -41568,7 +41739,7 @@ var ts;
                     startLine++;
                 }
                 var delta = indentation - nonWhitespaceColumnInFirstPart.column;
-                for (var i = startIndex, len = parts.length; i < len; ++i, ++startLine) {
+                for (var i = startIndex, len = parts.length; i < len; i++, startLine++) {
                     var startLinePos_1 = ts.getStartPositionOfLine(startLine, sourceFile);
                     var nonWhitespaceCharacterAndColumn = i === 0
                         ? nonWhitespaceColumnInFirstPart
@@ -41584,7 +41755,7 @@ var ts;
                 }
             }
             function trimTrailingWhitespacesForLines(line1, line2, range) {
-                for (var line = line1; line < line2; ++line) {
+                for (var line = line1; line < line2; line++) {
                     var lineStartPosition = ts.getStartPositionOfLine(line, sourceFile);
                     var lineEndPosition = ts.getEndLinePosition(line, sourceFile);
                     if (range && (ts.isComment(range.kind) || ts.isStringOrRegularExpressionOrTemplateLiteral(range.kind)) && range.pos <= lineEndPosition && range.end > lineEndPosition) {
@@ -41627,7 +41798,6 @@ var ts;
                 }
             }
             function applyRuleEdits(rule, previousRange, previousStartLine, currentRange, currentStartLine) {
-                var between;
                 switch (rule.Operation.Action) {
                     case 1:
                         return;
@@ -41657,14 +41827,6 @@ var ts;
                 }
             }
         }
-        function isSomeBlock(kind) {
-            switch (kind) {
-                case 199:
-                case 226:
-                    return true;
-            }
-            return false;
-        }
         function getOpenTokenForList(node, list) {
             switch (node.kind) {
                 case 148:
@@ -41722,7 +41884,7 @@ var ts;
                     internedTabsIndentation = [];
                 }
                 if (internedTabsIndentation[tabs] === undefined) {
-                    internedTabsIndentation[tabs] = tabString = repeat('\t', tabs);
+                    internedTabsIndentation[tabs] = tabString = repeat("\t", tabs);
                 }
                 else {
                     tabString = internedTabsIndentation[tabs];
@@ -41747,7 +41909,7 @@ var ts;
             }
             function repeat(value, count) {
                 var s = "";
-                for (var i = 0; i < count; ++i) {
+                for (var i = 0; i < count; i++) {
                     s += value;
                 }
                 return s;
@@ -42015,7 +42177,7 @@ var ts;
                 ts.Debug.assert(index >= 0 && index < list.length);
                 var node = list[index];
                 var lineAndCharacter = getStartLineAndCharacterForNode(node, sourceFile);
-                for (var i = index - 1; i >= 0; --i) {
+                for (var i = index - 1; i >= 0; i--) {
                     if (list[i].kind === 24) {
                         continue;
                     }
@@ -42034,7 +42196,7 @@ var ts;
             function findFirstNonWhitespaceCharacterAndColumn(startPos, endPos, sourceFile, options) {
                 var character = 0;
                 var column = 0;
-                for (var pos = startPos; pos < endPos; ++pos) {
+                for (var pos = startPos; pos < endPos; pos++) {
                     var ch = sourceFile.text.charCodeAt(pos);
                     if (!ts.isWhiteSpace(ch)) {
                         break;
@@ -44005,9 +44167,9 @@ 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_6 = new Date().getTime();
+                var start_5 = new Date().getTime();
                 contextToken = ts.findPrecedingToken(contextToken.getFullStart(), sourceFile);
-                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_6));
+                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_5));
             }
             var node = currentToken;
             var isRightOfDot = false;
@@ -44234,9 +44396,9 @@ var ts;
                     || contextToken.kind === 166
                     || contextToken.kind === 10
                     || ts.isTemplateLiteralKind(contextToken.kind)) {
-                    var start_7 = contextToken.getStart();
+                    var start_6 = contextToken.getStart();
                     var end = contextToken.getEnd();
-                    if (start_7 < position && position < end) {
+                    if (start_6 < position && position < end) {
                         return true;
                     }
                     if (position === end) {
@@ -45314,8 +45476,7 @@ var ts;
         }
         function getDocumentHighlights(fileName, position, filesToSearch) {
             synchronizeHostData();
-            filesToSearch = ts.map(filesToSearch, ts.normalizeSlashes);
-            var sourceFilesToSearch = ts.filter(program.getSourceFiles(), function (f) { return ts.contains(filesToSearch, f.fileName); });
+            var sourceFilesToSearch = ts.map(filesToSearch, function (f) { return program.getSourceFile(f); });
             var sourceFile = getValidSourceFile(fileName);
             var node = ts.getTouchingWord(sourceFile, position);
             if (!node) {
@@ -46498,7 +46659,8 @@ var ts;
         }
         function getNavigateToItems(searchValue, maxResultCount) {
             synchronizeHostData();
-            return ts.NavigateTo.getNavigateToItems(program, cancellationToken, searchValue, maxResultCount);
+            var checker = getProgram().getTypeChecker();
+            return ts.NavigateTo.getNavigateToItems(program, checker, cancellationToken, searchValue, maxResultCount);
         }
         function getEmitOutput(fileName) {
             synchronizeHostData();
@@ -50961,6 +51123,9 @@ var ts;
         LanguageServiceShimHostAdapter.prototype.getCurrentDirectory = function () {
             return this.shimHost.getCurrentDirectory();
         };
+        LanguageServiceShimHostAdapter.prototype.getDirectories = function (path) {
+            return this.shimHost.getDirectories(path);
+        };
         LanguageServiceShimHostAdapter.prototype.getDefaultLibFileName = function (options) {
             return this.shimHost.getDefaultLibFileName(JSON.stringify(options));
         };
diff --git a/lib/typescript.d.ts b/lib/typescript.d.ts
index 84a06001d14..1ac624055d7 100644
--- a/lib/typescript.d.ts
+++ b/lib/typescript.d.ts
@@ -261,7 +261,7 @@ declare namespace ts {
         ModuleDeclaration = 225,
         ModuleBlock = 226,
         CaseBlock = 227,
-        GlobalModuleExportDeclaration = 228,
+        NamespaceExportDeclaration = 228,
         ImportEqualsDeclaration = 229,
         ImportDeclaration = 230,
         ImportClause = 231,
@@ -934,7 +934,7 @@ declare namespace ts {
     interface NamespaceImport extends Declaration {
         name: Identifier;
     }
-    interface GlobalModuleExportDeclaration extends DeclarationStatement {
+    interface NamespaceExportDeclaration extends DeclarationStatement {
         name: Identifier;
         moduleReference: LiteralLikeNode;
     }
@@ -1329,7 +1329,7 @@ declare namespace ts {
         FunctionScopedVariableExcludes = 107454,
         BlockScopedVariableExcludes = 107455,
         ParameterExcludes = 107455,
-        PropertyExcludes = 107455,
+        PropertyExcludes = 0,
         EnumMemberExcludes = 107455,
         FunctionExcludes = 106927,
         ClassExcludes = 899519,
@@ -1554,6 +1554,7 @@ declare namespace ts {
         allowJs?: boolean;
         noImplicitUseStrict?: boolean;
         strictNullChecks?: boolean;
+        skipLibCheck?: boolean;
         listEmittedFiles?: boolean;
         lib?: string[];
         types?: string[];
@@ -1627,6 +1628,7 @@ declare namespace ts {
         trace?(s: string): void;
         directoryExists?(directoryName: string): boolean;
         realpath?(path: string): string;
+        getCurrentDirectory?(): string;
     }
     interface ResolvedModule {
         resolvedFileName: string;
@@ -1650,6 +1652,7 @@ declare namespace ts {
         getCancellationToken?(): CancellationToken;
         getDefaultLibFileName(options: CompilerOptions): string;
         getDefaultLibLocation?(): string;
+        getDefaultTypeDirectiveNames?(rootPath: string): string[];
         writeFile: WriteFileCallback;
         getCurrentDirectory(): string;
         getCanonicalFileName(fileName: string): string;
@@ -1693,6 +1696,7 @@ declare namespace ts {
         createDirectory(path: string): void;
         getExecutingFilePath(): string;
         getCurrentDirectory(): string;
+        getDirectories(path: string): string[];
         readDirectory(path: string, extension?: string, exclude?: string[]): string[];
         getModifiedTime?(path: string): Date;
         createHash?(data: string): string;
@@ -1812,6 +1816,7 @@ declare namespace ts {
     function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost;
     function getPreEmitDiagnostics(program: Program, sourceFile?: SourceFile, cancellationToken?: CancellationToken): Diagnostic[];
     function flattenDiagnosticMessageText(messageText: string | DiagnosticMessageChain, newLine: string): string;
+    function getDefaultTypeDirectiveNames(options: CompilerOptions, rootFiles: string[], host: CompilerHost): string[];
     function createProgram(rootNames: string[], options: CompilerOptions, host?: CompilerHost, oldProgram?: Program): Program;
 }
 declare namespace ts {
@@ -2345,26 +2350,55 @@ declare namespace ts {
     namespace ScriptElementKind {
         const unknown: string;
         const warning: string;
+        /** predefined type (void) or keyword (class) */
         const keyword: string;
+        /** top level script node */
         const scriptElement: string;
+        /** module foo {} */
         const moduleElement: string;
+        /** class X {} */
         const classElement: string;
+        /** var x = class X {} */
         const localClassElement: string;
+        /** interface Y {} */
         const interfaceElement: string;
+        /** type T = ... */
         const typeElement: string;
+        /** enum E */
         const enumElement: string;
+        /**
+         * Inside module and script only
+         * const v = ..
+         */
         const variableElement: string;
+        /** Inside function */
         const localVariableElement: string;
+        /**
+         * Inside module and script only
+         * function f() { }
+         */
         const functionElement: string;
+        /** Inside function */
         const localFunctionElement: string;
+        /** class X { [public|private]* foo() {} } */
         const memberFunctionElement: string;
+        /** class X { [public|private]* [get|set] foo:number; } */
         const memberGetAccessorElement: string;
         const memberSetAccessorElement: string;
+        /**
+         * class X { [public|private]* foo:number; }
+         * interface Y { foo:number; }
+         */
         const memberVariableElement: string;
+        /** class X { constructor() { } } */
         const constructorImplementationElement: string;
+        /** interface Y { ():number; } */
         const callSignatureElement: string;
+        /** interface Y { []:number; } */
         const indexSignatureElement: string;
+        /** interface Y { new():Y; } */
         const constructSignatureElement: string;
+        /** function foo(*Y*: string) */
         const parameterElement: string;
         const typeParameterElement: string;
         const primitiveType: string;
diff --git a/lib/typescript.js b/lib/typescript.js
index e78eda7b0bb..19fffd35501 100644
--- a/lib/typescript.js
+++ b/lib/typescript.js
@@ -271,7 +271,7 @@ var ts;
         SyntaxKind[SyntaxKind["ModuleDeclaration"] = 225] = "ModuleDeclaration";
         SyntaxKind[SyntaxKind["ModuleBlock"] = 226] = "ModuleBlock";
         SyntaxKind[SyntaxKind["CaseBlock"] = 227] = "CaseBlock";
-        SyntaxKind[SyntaxKind["GlobalModuleExportDeclaration"] = 228] = "GlobalModuleExportDeclaration";
+        SyntaxKind[SyntaxKind["NamespaceExportDeclaration"] = 228] = "NamespaceExportDeclaration";
         SyntaxKind[SyntaxKind["ImportEqualsDeclaration"] = 229] = "ImportEqualsDeclaration";
         SyntaxKind[SyntaxKind["ImportDeclaration"] = 230] = "ImportDeclaration";
         SyntaxKind[SyntaxKind["ImportClause"] = 231] = "ImportClause";
@@ -561,7 +561,7 @@ var ts;
         // they can not merge with anything in the value space
         SymbolFlags[SymbolFlags["BlockScopedVariableExcludes"] = 107455] = "BlockScopedVariableExcludes";
         SymbolFlags[SymbolFlags["ParameterExcludes"] = 107455] = "ParameterExcludes";
-        SymbolFlags[SymbolFlags["PropertyExcludes"] = 107455] = "PropertyExcludes";
+        SymbolFlags[SymbolFlags["PropertyExcludes"] = 0] = "PropertyExcludes";
         SymbolFlags[SymbolFlags["EnumMemberExcludes"] = 107455] = "EnumMemberExcludes";
         SymbolFlags[SymbolFlags["FunctionExcludes"] = 106927] = "FunctionExcludes";
         SymbolFlags[SymbolFlags["ClassExcludes"] = 899519] = "ClassExcludes";
@@ -1841,6 +1841,10 @@ var ts;
                 }
                 return result.sort();
             }
+            function getDirectories(path) {
+                var folder = fso.GetFolder(path);
+                return getNames(folder.subfolders);
+            }
             function readDirectory(path, extension, exclude) {
                 var result = [];
                 exclude = ts.map(exclude, function (s) { return getCanonicalPath(ts.combinePaths(path, s)); });
@@ -1895,6 +1899,7 @@ var ts;
                 getCurrentDirectory: function () {
                     return new ActiveXObject("WScript.Shell").CurrentDirectory;
                 },
+                getDirectories: getDirectories,
                 readDirectory: readDirectory,
                 exit: function (exitCode) {
                     try {
@@ -2057,6 +2062,9 @@ var ts;
             function directoryExists(path) {
                 return fileSystemEntryExists(path, 1 /* Directory */);
             }
+            function getDirectories(path) {
+                return ts.filter(_fs.readdirSync(path), function (p) { return fileSystemEntryExists(ts.combinePaths(path, p), 1 /* Directory */); });
+            }
             function readDirectory(path, extension, exclude) {
                 var result = [];
                 exclude = ts.map(exclude, function (s) { return getCanonicalPath(ts.combinePaths(path, s)); });
@@ -2157,6 +2165,7 @@ var ts;
                 getCurrentDirectory: function () {
                     return process.cwd();
                 },
+                getDirectories: getDirectories,
                 readDirectory: readDirectory,
                 getModifiedTime: function (path) {
                     try {
@@ -2209,6 +2218,7 @@ var ts;
                 createDirectory: ChakraHost.createDirectory,
                 getExecutingFilePath: function () { return ChakraHost.executingFile; },
                 getCurrentDirectory: function () { return ChakraHost.currentDirectory; },
+                getDirectories: ChakraHost.getDirectories,
                 readDirectory: ChakraHost.readDirectory,
                 exit: ChakraHost.quit,
                 realpath: realpath
@@ -2347,7 +2357,7 @@ var ts;
         or_expected: { code: 1144, category: ts.DiagnosticCategory.Error, key: "or_expected_1144", message: "'{' or ';' expected." },
         Declaration_expected: { code: 1146, category: ts.DiagnosticCategory.Error, key: "Declaration_expected_1146", message: "Declaration expected." },
         Import_declarations_in_a_namespace_cannot_reference_a_module: { code: 1147, category: ts.DiagnosticCategory.Error, key: "Import_declarations_in_a_namespace_cannot_reference_a_module_1147", message: "Import declarations in a namespace cannot reference a module." },
-        Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file: { code: 1148, category: ts.DiagnosticCategory.Error, key: "Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting__1148", message: "Cannot compile modules unless the '--module' flag is provided with a valid module type. Consider setting the 'module' compiler option in a 'tsconfig.json' file." },
+        Cannot_use_imports_exports_or_module_augmentations_when_module_is_none: { code: 1148, category: ts.DiagnosticCategory.Error, key: "Cannot_use_imports_exports_or_module_augmentations_when_module_is_none_1148", message: "Cannot use imports, exports, or module augmentations when '--module' is 'none'." },
         File_name_0_differs_from_already_included_file_name_1_only_in_casing: { code: 1149, category: ts.DiagnosticCategory.Error, key: "File_name_0_differs_from_already_included_file_name_1_only_in_casing_1149", message: "File name '{0}' differs from already included file name '{1}' only in casing" },
         new_T_cannot_be_used_to_create_an_array_Use_new_Array_T_instead: { code: 1150, category: ts.DiagnosticCategory.Error, key: "new_T_cannot_be_used_to_create_an_array_Use_new_Array_T_instead_1150", message: "'new T[]' cannot be used to create an array. Use 'new Array<T>()' instead." },
         const_declarations_must_be_initialized: { code: 1155, category: ts.DiagnosticCategory.Error, key: "const_declarations_must_be_initialized_1155", message: "'const' declarations must be initialized" },
@@ -2717,6 +2727,8 @@ var ts;
         this_implicitly_has_type_any_because_it_does_not_have_a_type_annotation: { code: 2683, category: ts.DiagnosticCategory.Error, key: "this_implicitly_has_type_any_because_it_does_not_have_a_type_annotation_2683", message: "'this' implicitly has type 'any' because it does not have a type annotation." },
         The_this_context_of_type_0_is_not_assignable_to_method_s_this_of_type_1: { code: 2684, category: ts.DiagnosticCategory.Error, key: "The_this_context_of_type_0_is_not_assignable_to_method_s_this_of_type_1_2684", message: "The 'this' context of type '{0}' is not assignable to method's 'this' of type '{1}'." },
         The_this_types_of_each_signature_are_incompatible: { code: 2685, category: ts.DiagnosticCategory.Error, key: "The_this_types_of_each_signature_are_incompatible_2685", message: "The 'this' types of each signature are incompatible." },
+        Identifier_0_must_be_imported_from_a_module: { code: 2686, category: ts.DiagnosticCategory.Error, key: "Identifier_0_must_be_imported_from_a_module_2686", message: "Identifier '{0}' must be imported from a module" },
+        All_declarations_of_0_must_have_identical_modifiers: { code: 2687, category: ts.DiagnosticCategory.Error, key: "All_declarations_of_0_must_have_identical_modifiers_2687", message: "All declarations of '{0}' must have identical modifiers." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: ts.DiagnosticCategory.Error, key: "Import_declaration_0_is_using_private_name_1_4000", message: "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_4002", message: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
         Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1: { code: 4004, category: ts.DiagnosticCategory.Error, key: "Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1_4004", message: "Type parameter '{0}' of exported interface has or is using private name '{1}'." },
@@ -2810,7 +2822,7 @@ var ts;
         Option_paths_cannot_be_used_without_specifying_baseUrl_option: { code: 5060, category: ts.DiagnosticCategory.Error, key: "Option_paths_cannot_be_used_without_specifying_baseUrl_option_5060", message: "Option 'paths' cannot be used without specifying '--baseUrl' option." },
         Pattern_0_can_have_at_most_one_Asterisk_character: { code: 5061, category: ts.DiagnosticCategory.Error, key: "Pattern_0_can_have_at_most_one_Asterisk_character_5061", message: "Pattern '{0}' can have at most one '*' character" },
         Substitution_0_in_pattern_1_in_can_have_at_most_one_Asterisk_character: { code: 5062, category: ts.DiagnosticCategory.Error, key: "Substitution_0_in_pattern_1_in_can_have_at_most_one_Asterisk_character_5062", message: "Substitution '{0}' in pattern '{1}' in can have at most one '*' character" },
-        Substututions_for_pattern_0_should_be_an_array: { code: 5063, category: ts.DiagnosticCategory.Error, key: "Substututions_for_pattern_0_should_be_an_array_5063", message: "Substututions for pattern '{0}' should be an array." },
+        Substitutions_for_pattern_0_should_be_an_array: { code: 5063, category: ts.DiagnosticCategory.Error, key: "Substitutions_for_pattern_0_should_be_an_array_5063", message: "Substitutions for pattern '{0}' should be an array." },
         Substitution_0_for_pattern_1_has_incorrect_type_expected_string_got_2: { code: 5064, category: ts.DiagnosticCategory.Error, key: "Substitution_0_for_pattern_1_has_incorrect_type_expected_string_got_2_5064", message: "Substitution '{0}' for pattern '{1}' has incorrect type, expected 'string', got '{2}'." },
         Concatenate_and_emit_output_to_single_file: { code: 6001, category: ts.DiagnosticCategory.Message, key: "Concatenate_and_emit_output_to_single_file_6001", message: "Concatenate and emit output to single file." },
         Generates_corresponding_d_ts_file: { code: 6002, category: ts.DiagnosticCategory.Message, key: "Generates_corresponding_d_ts_file_6002", message: "Generates corresponding '.d.ts' file." },
@@ -2823,6 +2835,7 @@ var ts;
         Do_not_emit_comments_to_output: { code: 6009, category: ts.DiagnosticCategory.Message, key: "Do_not_emit_comments_to_output_6009", message: "Do not emit comments to output." },
         Do_not_emit_outputs: { code: 6010, category: ts.DiagnosticCategory.Message, key: "Do_not_emit_outputs_6010", message: "Do not emit outputs." },
         Allow_default_imports_from_modules_with_no_default_export_This_does_not_affect_code_emit_just_typechecking: { code: 6011, category: ts.DiagnosticCategory.Message, key: "Allow_default_imports_from_modules_with_no_default_export_This_does_not_affect_code_emit_just_typech_6011", message: "Allow default imports from modules with no default export. This does not affect code emit, just typechecking." },
+        Skip_type_checking_of_declaration_files: { code: 6012, category: ts.DiagnosticCategory.Message, key: "Skip_type_checking_of_declaration_files_6012", message: "Skip type checking of declaration files." },
         Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015: { code: 6015, category: ts.DiagnosticCategory.Message, key: "Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015_6015", message: "Specify ECMAScript target version: 'ES3' (default), 'ES5', or 'ES2015'" },
         Specify_module_code_generation_Colon_commonjs_amd_system_umd_or_es2015: { code: 6016, category: ts.DiagnosticCategory.Message, key: "Specify_module_code_generation_Colon_commonjs_amd_system_umd_or_es2015_6016", message: "Specify module code generation: 'commonjs', 'amd', 'system', 'umd' or 'es2015'" },
         Print_this_message: { code: 6017, category: ts.DiagnosticCategory.Message, key: "Print_this_message_6017", message: "Print this message." },
@@ -2924,6 +2937,7 @@ var ts;
         Resolving_type_reference_directive_0_containing_file_not_set_root_directory_not_set: { code: 6128, category: ts.DiagnosticCategory.Message, key: "Resolving_type_reference_directive_0_containing_file_not_set_root_directory_not_set_6128", message: "======== Resolving type reference directive '{0}', containing file not set, root directory not set. ========" },
         The_config_file_0_found_doesn_t_contain_any_source_files: { code: 6129, category: ts.DiagnosticCategory.Error, key: "The_config_file_0_found_doesn_t_contain_any_source_files_6129", message: "The config file '{0}' found doesn't contain any source files." },
         Resolving_real_path_for_0_result_1: { code: 6130, category: ts.DiagnosticCategory.Message, key: "Resolving_real_path_for_0_result_1_6130", message: "Resolving real path for '{0}', result '{1}'" },
+        Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system: { code: 6131, category: ts.DiagnosticCategory.Error, key: "Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system_6131", message: "Cannot compile modules using option '{0}' unless the '--module' flag is 'amd' or 'system'." },
         Variable_0_implicitly_has_an_1_type: { code: 7005, category: ts.DiagnosticCategory.Error, key: "Variable_0_implicitly_has_an_1_type_7005", message: "Variable '{0}' implicitly has an '{1}' type." },
         Parameter_0_implicitly_has_an_1_type: { code: 7006, category: ts.DiagnosticCategory.Error, key: "Parameter_0_implicitly_has_an_1_type_7006", message: "Parameter '{0}' implicitly has an '{1}' type." },
         Member_0_implicitly_has_an_1_type: { code: 7008, category: ts.DiagnosticCategory.Error, key: "Member_0_implicitly_has_an_1_type_7008", message: "Member '{0}' implicitly has an '{1}' type." },
@@ -6172,7 +6186,7 @@ var ts;
     // export default ...
     function isAliasSymbolDeclaration(node) {
         return node.kind === 229 /* ImportEqualsDeclaration */ ||
-            node.kind === 228 /* GlobalModuleExportDeclaration */ ||
+            node.kind === 228 /* NamespaceExportDeclaration */ ||
             node.kind === 231 /* ImportClause */ && !!node.name ||
             node.kind === 232 /* NamespaceImport */ ||
             node.kind === 234 /* ImportSpecifier */ ||
@@ -6301,7 +6315,7 @@ var ts;
     }
     ts.isWellKnownSymbolSyntactically = isWellKnownSymbolSyntactically;
     function getPropertyNameForPropertyNameNode(name) {
-        if (name.kind === 69 /* Identifier */ || name.kind === 9 /* StringLiteral */ || name.kind === 8 /* NumericLiteral */) {
+        if (name.kind === 69 /* Identifier */ || name.kind === 9 /* StringLiteral */ || name.kind === 8 /* NumericLiteral */ || name.kind === 142 /* Parameter */) {
             return name.text;
         }
         if (name.kind === 140 /* ComputedPropertyName */) {
@@ -7773,7 +7787,7 @@ var ts;
             case 231 /* ImportClause */:
                 return visitNode(cbNode, node.name) ||
                     visitNode(cbNode, node.namedBindings);
-            case 228 /* GlobalModuleExportDeclaration */:
+            case 228 /* NamespaceExportDeclaration */:
                 return visitNode(cbNode, node.name);
             case 232 /* NamespaceImport */:
                 return visitNode(cbNode, node.name);
@@ -12182,7 +12196,7 @@ var ts;
             return nextToken() === 39 /* SlashToken */;
         }
         function parseGlobalModuleExportDeclaration(fullStart, decorators, modifiers) {
-            var exportDeclaration = createNode(228 /* GlobalModuleExportDeclaration */, fullStart);
+            var exportDeclaration = createNode(228 /* NamespaceExportDeclaration */, fullStart);
             exportDeclaration.decorators = decorators;
             exportDeclaration.modifiers = modifiers;
             parseExpected(116 /* AsKeyword */);
@@ -15018,10 +15032,10 @@ var ts;
                 case 145 /* PropertyDeclaration */:
                 case 144 /* PropertySignature */:
                 case 266 /* JSDocRecordMember */:
-                    return bindPropertyOrMethodOrAccessor(node, 4 /* Property */ | (node.questionToken ? 536870912 /* Optional */ : 0 /* None */), 107455 /* PropertyExcludes */);
+                    return bindPropertyOrMethodOrAccessor(node, 4 /* Property */ | (node.questionToken ? 536870912 /* Optional */ : 0 /* None */), 0 /* PropertyExcludes */);
                 case 253 /* PropertyAssignment */:
                 case 254 /* ShorthandPropertyAssignment */:
-                    return bindPropertyOrMethodOrAccessor(node, 4 /* Property */, 107455 /* PropertyExcludes */);
+                    return bindPropertyOrMethodOrAccessor(node, 4 /* Property */, 0 /* PropertyExcludes */);
                 case 255 /* EnumMember */:
                     return bindPropertyOrMethodOrAccessor(node, 8 /* EnumMember */, 107455 /* EnumMemberExcludes */);
                 case 247 /* JsxSpreadAttribute */:
@@ -15037,7 +15051,7 @@ var ts;
                     // as other properties in the object literal.  So we use SymbolFlags.PropertyExcludes
                     // so that it will conflict with any other object literal members with the same
                     // name.
-                    return bindPropertyOrMethodOrAccessor(node, 8192 /* Method */ | (node.questionToken ? 536870912 /* Optional */ : 0 /* None */), ts.isObjectLiteralMethod(node) ? 107455 /* PropertyExcludes */ : 99263 /* MethodExcludes */);
+                    return bindPropertyOrMethodOrAccessor(node, 8192 /* Method */ | (node.questionToken ? 536870912 /* Optional */ : 0 /* None */), ts.isObjectLiteralMethod(node) ? 0 /* PropertyExcludes */ : 99263 /* MethodExcludes */);
                 case 220 /* FunctionDeclaration */:
                     return bindFunctionDeclaration(node);
                 case 148 /* Constructor */:
@@ -15081,8 +15095,8 @@ var ts;
                 case 234 /* ImportSpecifier */:
                 case 238 /* ExportSpecifier */:
                     return declareSymbolAndAddToSymbolTable(node, 8388608 /* Alias */, 8388608 /* AliasExcludes */);
-                case 228 /* GlobalModuleExportDeclaration */:
-                    return bindGlobalModuleExportDeclaration(node);
+                case 228 /* NamespaceExportDeclaration */:
+                    return bindNamespaceExportDeclaration(node);
                 case 231 /* ImportClause */:
                     return bindImportClause(node);
                 case 236 /* ExportDeclaration */:
@@ -15120,14 +15134,14 @@ var ts;
             }
             else if (boundExpression.kind === 69 /* Identifier */ && node.kind === 235 /* ExportAssignment */) {
                 // An export default clause with an identifier exports all meanings of that identifier
-                declareSymbol(container.symbol.exports, container.symbol, node, 8388608 /* Alias */, 107455 /* PropertyExcludes */ | 8388608 /* AliasExcludes */);
+                declareSymbol(container.symbol.exports, container.symbol, node, 8388608 /* Alias */, 0 /* PropertyExcludes */ | 8388608 /* AliasExcludes */);
             }
             else {
                 // An export default clause with an expression exports a value
-                declareSymbol(container.symbol.exports, container.symbol, node, 4 /* Property */, 107455 /* PropertyExcludes */ | 8388608 /* AliasExcludes */);
+                declareSymbol(container.symbol.exports, container.symbol, node, 4 /* Property */, 0 /* PropertyExcludes */ | 8388608 /* AliasExcludes */);
             }
         }
-        function bindGlobalModuleExportDeclaration(node) {
+        function bindNamespaceExportDeclaration(node) {
             if (node.modifiers && node.modifiers.length) {
                 file.bindDiagnostics.push(ts.createDiagnosticForNode(node, ts.Diagnostics.Modifiers_cannot_appear_here));
             }
@@ -15186,7 +15200,7 @@ var ts;
             if (container.kind === 179 /* FunctionExpression */ || container.kind === 220 /* FunctionDeclaration */) {
                 container.symbol.members = container.symbol.members || {};
                 // It's acceptable for multiple 'this' assignments of the same identifier to occur
-                declareSymbol(container.symbol.members, container.symbol, node, 4 /* Property */, 107455 /* PropertyExcludes */ & ~4 /* Property */);
+                declareSymbol(container.symbol.members, container.symbol, node, 4 /* Property */, 0 /* PropertyExcludes */ & ~4 /* Property */);
             }
         }
         function bindPrototypePropertyAssignment(node) {
@@ -15209,7 +15223,7 @@ var ts;
                 funcSymbol.members = {};
             }
             // Declare the method/property
-            declareSymbol(funcSymbol.members, funcSymbol, leftSideOfAssignment, 4 /* Property */, 107455 /* PropertyExcludes */);
+            declareSymbol(funcSymbol.members, funcSymbol, leftSideOfAssignment, 4 /* Property */, 0 /* PropertyExcludes */);
         }
         function bindCallExpression(node) {
             // We're only inspecting call expressions to detect CommonJS modules, so we can skip
@@ -15310,7 +15324,7 @@ var ts;
             // containing class.
             if (ts.isParameterPropertyDeclaration(node)) {
                 var classDeclaration = node.parent.parent;
-                declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, 4 /* Property */, 107455 /* PropertyExcludes */);
+                declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, 4 /* Property */, 0 /* PropertyExcludes */);
             }
         }
         function bindFunctionDeclaration(node) {
@@ -15696,7 +15710,7 @@ var ts;
             if (flags & 1 /* FunctionScopedVariable */)
                 result |= 107454 /* FunctionScopedVariableExcludes */;
             if (flags & 4 /* Property */)
-                result |= 107455 /* PropertyExcludes */;
+                result |= 0 /* PropertyExcludes */;
             if (flags & 8 /* EnumMember */)
                 result |= 107455 /* EnumMemberExcludes */;
             if (flags & 16 /* Function */)
@@ -15982,6 +15996,7 @@ var ts;
             var propertyWithInvalidInitializer;
             var errorLocation = location;
             var grandparent;
+            var isInExternalModule = false;
             loop: while (location) {
                 // Locals of a source file are not in scope (because they get merged into the global symbol table)
                 if (location.locals && !isGlobalSourceFile(location)) {
@@ -16024,6 +16039,7 @@ var ts;
                     case 256 /* SourceFile */:
                         if (!ts.isExternalOrCommonJsModule(location))
                             break;
+                        isInExternalModule = true;
                     case 225 /* ModuleDeclaration */:
                         var moduleExports = getSymbolOfNode(location).exports;
                         if (location.kind === 256 /* SourceFile */ || ts.isAmbientModule(location)) {
@@ -16207,6 +16223,13 @@ var ts;
                         checkResolvedBlockScopedVariable(exportOrLocalSymbol, errorLocation);
                     }
                 }
+                // If we're in an external module, we can't reference symbols created from UMD export declarations
+                if (result && isInExternalModule) {
+                    var decls = result.declarations;
+                    if (decls && decls.length === 1 && decls[0].kind === 228 /* NamespaceExportDeclaration */) {
+                        error(errorLocation, ts.Diagnostics.Identifier_0_must_be_imported_from_a_module, name);
+                    }
+                }
             }
             return result;
         }
@@ -16409,7 +16432,7 @@ var ts;
                     return getTargetOfExportSpecifier(node);
                 case 235 /* ExportAssignment */:
                     return getTargetOfExportAssignment(node);
-                case 228 /* GlobalModuleExportDeclaration */:
+                case 228 /* NamespaceExportDeclaration */:
                     return getTargetOfGlobalModuleExportDeclaration(node);
             }
         }
@@ -17883,7 +17906,7 @@ var ts;
         // assigned by contextual typing.
         function getTypeForBindingElementParent(node) {
             var symbol = getSymbolOfNode(node);
-            return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node);
+            return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node, /*includeOptionality*/ false);
         }
         function getTextOfPropertyName(name) {
             switch (name.kind) {
@@ -18009,7 +18032,7 @@ var ts;
             return strictNullChecks && optional ? addNullableKind(type, 32 /* Undefined */) : type;
         }
         // Return the inferred type for a variable, parameter, or property declaration
-        function getTypeForVariableLikeDeclaration(declaration) {
+        function getTypeForVariableLikeDeclaration(declaration, includeOptionality) {
             if (declaration.flags & 134217728 /* JavaScriptFile */) {
                 // If this is a variable in a JavaScript file, then use the JSDoc type (if it has
                 // one as its type), otherwise fallback to the below standard TS codepaths to
@@ -18035,7 +18058,7 @@ var ts;
             }
             // Use type from type annotation if one is present
             if (declaration.type) {
-                return addOptionality(getTypeFromTypeNode(declaration.type), /*optional*/ !!declaration.questionToken);
+                return addOptionality(getTypeFromTypeNode(declaration.type), /*optional*/ declaration.questionToken && includeOptionality);
             }
             if (declaration.kind === 142 /* Parameter */) {
                 var func = declaration.parent;
@@ -18056,12 +18079,12 @@ var ts;
                     ? getContextuallyTypedThisType(func)
                     : getContextuallyTypedParameterType(declaration);
                 if (type) {
-                    return addOptionality(type, /*optional*/ !!declaration.questionToken);
+                    return addOptionality(type, /*optional*/ declaration.questionToken && includeOptionality);
                 }
             }
             // Use the type of the initializer expression if one is present
             if (declaration.initializer) {
-                return addOptionality(checkExpressionCached(declaration.initializer), /*optional*/ !!declaration.questionToken);
+                return addOptionality(checkExpressionCached(declaration.initializer), /*optional*/ declaration.questionToken && includeOptionality);
             }
             // If it is a short-hand property assignment, use the type of the identifier
             if (declaration.kind === 254 /* ShorthandPropertyAssignment */) {
@@ -18155,7 +18178,7 @@ var ts;
         // binding pattern [x, s = ""]. Because the contextual type is a tuple type, the resulting type of [1, "one"] is the
         // tuple type [number, string]. Thus, the type inferred for 'x' is number and the type inferred for 's' is string.
         function getWidenedTypeForVariableLikeDeclaration(declaration, reportErrors) {
-            var type = getTypeForVariableLikeDeclaration(declaration);
+            var type = getTypeForVariableLikeDeclaration(declaration, /*includeOptionality*/ true);
             if (type) {
                 if (reportErrors) {
                     reportErrorsFromWidening(declaration, type);
@@ -20719,7 +20742,7 @@ var ts;
                     return isIdenticalTo(source, target);
                 }
                 if (!(target.flags & 134217728 /* Never */)) {
-                    if (target.flags & 1 /* Any */)
+                    if (target.flags & 1 /* Any */ || source.flags & 134217728 /* Never */)
                         return -1 /* True */;
                     if (source.flags & 32 /* Undefined */) {
                         if (!strictNullChecks || target.flags & (32 /* Undefined */ | 16 /* Void */) || source === emptyArrayElementType)
@@ -20739,7 +20762,7 @@ var ts;
                     if (source.flags & 256 /* StringLiteral */ && target === stringType)
                         return -1 /* True */;
                     if (relation === assignableRelation || relation === comparableRelation) {
-                        if (source.flags & (1 /* Any */ | 134217728 /* Never */))
+                        if (source.flags & 1 /* Any */)
                             return -1 /* True */;
                         if (source === numberType && target.flags & 128 /* Enum */)
                             return -1 /* True */;
@@ -21634,41 +21657,52 @@ var ts;
                 getSignaturesOfType(type, 0 /* Call */).length === 0 &&
                 getSignaturesOfType(type, 1 /* Construct */).length === 0;
         }
+        function createTransientSymbol(source, type) {
+            var symbol = createSymbol(source.flags | 67108864 /* Transient */, source.name);
+            symbol.declarations = source.declarations;
+            symbol.parent = source.parent;
+            symbol.type = type;
+            symbol.target = source;
+            if (source.valueDeclaration) {
+                symbol.valueDeclaration = source.valueDeclaration;
+            }
+            return symbol;
+        }
+        function transformTypeOfMembers(type, f) {
+            var members = {};
+            for (var _i = 0, _a = getPropertiesOfObjectType(type); _i < _a.length; _i++) {
+                var property = _a[_i];
+                var original = getTypeOfSymbol(property);
+                var updated = f(original);
+                members[property.name] = updated === original ? property : createTransientSymbol(property, updated);
+            }
+            ;
+            return members;
+        }
+        /**
+         * If the the provided object literal is subject to the excess properties check,
+         * create a new that is exempt. Recursively mark object literal members as exempt.
+         * Leave signatures alone since they are not subject to the check.
+         */
         function getRegularTypeOfObjectLiteral(type) {
-            if (type.flags & 1048576 /* FreshObjectLiteral */) {
-                var regularType = type.regularType;
-                if (!regularType) {
-                    regularType = createType(type.flags & ~1048576 /* FreshObjectLiteral */);
-                    regularType.symbol = type.symbol;
-                    regularType.members = type.members;
-                    regularType.properties = type.properties;
-                    regularType.callSignatures = type.callSignatures;
-                    regularType.constructSignatures = type.constructSignatures;
-                    regularType.stringIndexInfo = type.stringIndexInfo;
-                    regularType.numberIndexInfo = type.numberIndexInfo;
-                    type.regularType = regularType;
-                }
+            if (!(type.flags & 1048576 /* FreshObjectLiteral */)) {
+                return type;
+            }
+            var regularType = type.regularType;
+            if (regularType) {
                 return regularType;
             }
-            return type;
+            var resolved = type;
+            var members = transformTypeOfMembers(type, getRegularTypeOfObjectLiteral);
+            var regularNew = createAnonymousType(resolved.symbol, members, resolved.callSignatures, resolved.constructSignatures, resolved.stringIndexInfo, resolved.numberIndexInfo);
+            regularNew.flags = resolved.flags & ~1048576 /* FreshObjectLiteral */;
+            type.regularType = regularNew;
+            return regularNew;
         }
         function getWidenedTypeOfObjectLiteral(type) {
-            var properties = getPropertiesOfObjectType(type);
-            var members = {};
-            ts.forEach(properties, function (p) {
-                var propType = getTypeOfSymbol(p);
-                var widenedType = getWidenedType(propType);
-                if (propType !== widenedType) {
-                    var symbol = createSymbol(p.flags | 67108864 /* Transient */, p.name);
-                    symbol.declarations = p.declarations;
-                    symbol.parent = p.parent;
-                    symbol.type = widenedType;
-                    symbol.target = p;
-                    if (p.valueDeclaration)
-                        symbol.valueDeclaration = p.valueDeclaration;
-                    p = symbol;
-                }
-                members[p.name] = p;
+            var members = transformTypeOfMembers(type, function (prop) {
+                var widened = getWidenedType(prop);
+                return prop === widened ? prop : widened;
             });
             var stringIndexInfo = getIndexInfoOfType(type, 0 /* String */);
             var numberIndexInfo = getIndexInfoOfType(type, 1 /* Number */);
@@ -23224,7 +23258,7 @@ var ts;
             }
             return nodeCheckFlag === 512 /* SuperStatic */
                 ? getBaseConstructorTypeOfClass(classType)
-                : baseClassType;
+                : getTypeWithThisArgument(baseClassType, classType.thisType);
             function isLegalUsageOfSuperExpression(container) {
                 if (!container) {
                     return false;
@@ -25936,7 +25970,7 @@ var ts;
                 var types = void 0;
                 var funcIsGenerator = !!func.asteriskToken;
                 if (funcIsGenerator) {
-                    types = checkAndAggregateYieldOperandTypes(func.body, contextualMapper);
+                    types = checkAndAggregateYieldOperandTypes(func, contextualMapper);
                     if (types.length === 0) {
                         var iterableIteratorAny = createIterableIteratorType(anyType);
                         if (compilerOptions.noImplicitAny) {
@@ -25946,8 +25980,7 @@ var ts;
                     }
                 }
                 else {
-                    var hasImplicitReturn = !!(func.flags & 32768 /* HasImplicitReturn */);
-                    types = checkAndAggregateReturnExpressionTypes(func.body, contextualMapper, isAsync, hasImplicitReturn);
+                    types = checkAndAggregateReturnExpressionTypes(func, contextualMapper);
                     if (!types) {
                         return neverType;
                     }
@@ -26001,9 +26034,9 @@ var ts;
                 return widenedType;
             }
         }
-        function checkAndAggregateYieldOperandTypes(body, contextualMapper) {
+        function checkAndAggregateYieldOperandTypes(func, contextualMapper) {
             var aggregatedTypes = [];
-            ts.forEachYieldExpression(body, function (yieldExpression) {
+            ts.forEachYieldExpression(func.body, function (yieldExpression) {
                 var expr = yieldExpression.expression;
                 if (expr) {
                     var type = checkExpressionCached(expr, contextualMapper);
@@ -26018,10 +26051,12 @@ var ts;
             });
             return aggregatedTypes;
         }
-        function checkAndAggregateReturnExpressionTypes(body, contextualMapper, isAsync, hasImplicitReturn) {
+        function checkAndAggregateReturnExpressionTypes(func, contextualMapper) {
+            var isAsync = ts.isAsyncFunctionLike(func);
             var aggregatedTypes = [];
-            var hasOmittedExpressions = false;
-            ts.forEachReturnStatement(body, function (returnStatement) {
+            var hasReturnWithNoExpression = !!(func.flags & 32768 /* HasImplicitReturn */);
+            var hasReturnOfTypeNever = false;
+            ts.forEachReturnStatement(func.body, function (returnStatement) {
                 var expr = returnStatement.expression;
                 if (expr) {
                     var type = checkExpressionCached(expr, contextualMapper);
@@ -26030,20 +26065,24 @@ var ts;
                         // Promise/A+ compatible implementation will always assimilate any foreign promise, so the
                         // return type of the body should be unwrapped to its awaited type, which should be wrapped in
                         // the native Promise<T> type by the caller.
-                        type = checkAwaitedType(type, body.parent, ts.Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
+                        type = checkAwaitedType(type, func, ts.Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
                     }
-                    if (type !== neverType && !ts.contains(aggregatedTypes, type)) {
+                    if (type === neverType) {
+                        hasReturnOfTypeNever = true;
+                    }
+                    else if (!ts.contains(aggregatedTypes, type)) {
                         aggregatedTypes.push(type);
                     }
                 }
                 else {
-                    hasOmittedExpressions = true;
+                    hasReturnWithNoExpression = true;
                 }
             });
-            if (aggregatedTypes.length === 0 && !hasOmittedExpressions && !hasImplicitReturn) {
+            if (aggregatedTypes.length === 0 && !hasReturnWithNoExpression && (hasReturnOfTypeNever ||
+                func.kind === 179 /* FunctionExpression */ || func.kind === 180 /* ArrowFunction */)) {
                 return undefined;
             }
-            if (strictNullChecks && aggregatedTypes.length && (hasOmittedExpressions || hasImplicitReturn)) {
+            if (strictNullChecks && aggregatedTypes.length && hasReturnWithNoExpression) {
                 if (!ts.contains(aggregatedTypes, undefinedType)) {
                     aggregatedTypes.push(undefinedType);
                 }
@@ -26215,8 +26254,14 @@ var ts;
                 if (symbol.flags & 4 /* Property */ &&
                     (expr.kind === 172 /* PropertyAccessExpression */ || expr.kind === 173 /* ElementAccessExpression */) &&
                     expr.expression.kind === 97 /* ThisKeyword */) {
+                    // Look for if this is the constructor for the class that `symbol` is a property of.
                     var func = ts.getContainingFunction(expr);
-                    return !(func && func.kind === 148 /* Constructor */ && func.parent === symbol.valueDeclaration.parent);
+                    if (!(func && func.kind === 148 /* Constructor */))
+                        return true;
+                    // If func.parent is a class and symbol is a (readonly) property of that class, or
+                    // if func is a constructor and symbol is a (readonly) parameter property declared in it,
+                    // then symbol is writeable here.
+                    return !(func.parent === symbol.valueDeclaration.parent || func === symbol.valueDeclaration.parent);
                 }
                 return true;
             }
@@ -27148,6 +27193,79 @@ var ts;
                 }
             }
         }
+        function checkClassForDuplicateDeclarations(node) {
+            var getter = 1, setter = 2, property = getter | setter;
+            var instanceNames = {};
+            var staticNames = {};
+            for (var _i = 0, _a = node.members; _i < _a.length; _i++) {
+                var member = _a[_i];
+                if (member.kind === 148 /* Constructor */) {
+                    for (var _b = 0, _c = member.parameters; _b < _c.length; _b++) {
+                        var param = _c[_b];
+                        if (ts.isParameterPropertyDeclaration(param)) {
+                            addName(instanceNames, param.name, param.name.text, property);
+                        }
+                    }
+                }
+                else {
+                    var static = ts.forEach(member.modifiers, function (m) { return m.kind === 113 /* StaticKeyword */; });
+                    var names = static ? staticNames : instanceNames;
+                    var memberName = member.name && ts.getPropertyNameForPropertyNameNode(member.name);
+                    if (memberName) {
+                        switch (member.kind) {
+                            case 149 /* GetAccessor */:
+                                addName(names, member.name, memberName, getter);
+                                break;
+                            case 150 /* SetAccessor */:
+                                addName(names, member.name, memberName, setter);
+                                break;
+                            case 145 /* PropertyDeclaration */:
+                                addName(names, member.name, memberName, property);
+                                break;
+                        }
+                    }
+                }
+            }
+            function addName(names, location, name, meaning) {
+                if (ts.hasProperty(names, name)) {
+                    var prev = names[name];
+                    if (prev & meaning) {
+                        error(location, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(location));
+                    }
+                    else {
+                        names[name] = prev | meaning;
+                    }
+                }
+                else {
+                    names[name] = meaning;
+                }
+            }
+        }
+        function checkObjectTypeForDuplicateDeclarations(node) {
+            var names = {};
+            for (var _i = 0, _a = node.members; _i < _a.length; _i++) {
+                var member = _a[_i];
+                if (member.kind == 144 /* PropertySignature */) {
+                    var memberName = void 0;
+                    switch (member.name.kind) {
+                        case 9 /* StringLiteral */:
+                        case 8 /* NumericLiteral */:
+                        case 69 /* Identifier */:
+                            memberName = member.name.text;
+                            break;
+                        default:
+                            continue;
+                    }
+                    if (ts.hasProperty(names, memberName)) {
+                        error(member.symbol.valueDeclaration.name, ts.Diagnostics.Duplicate_identifier_0, memberName);
+                        error(member.name, ts.Diagnostics.Duplicate_identifier_0, memberName);
+                    }
+                    else {
+                        names[memberName] = true;
+                    }
+                }
+            }
+        }
         function checkTypeForDuplicateIndexSignatures(node) {
             if (node.kind === 222 /* InterfaceDeclaration */) {
                 var nodeSymbol = getSymbolOfNode(node);
@@ -27399,6 +27517,7 @@ var ts;
                 var type = getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node);
                 checkIndexConstraints(type);
                 checkTypeForDuplicateIndexSignatures(node);
+                checkObjectTypeForDuplicateDeclarations(node);
             }
         }
         function checkArrayType(node) {
@@ -28444,6 +28563,10 @@ var ts;
                 if (node.initializer) {
                     checkTypeAssignableTo(checkExpressionCached(node.initializer), declarationType, node, /*headMessage*/ undefined);
                 }
+                if (!areDeclarationFlagsIdentical(node, symbol.valueDeclaration)) {
+                    error(symbol.valueDeclaration.name, ts.Diagnostics.All_declarations_of_0_must_have_identical_modifiers, ts.declarationNameToString(node.name));
+                    error(node.name, ts.Diagnostics.All_declarations_of_0_must_have_identical_modifiers, ts.declarationNameToString(node.name));
+                }
             }
             if (node.kind !== 145 /* PropertyDeclaration */ && node.kind !== 144 /* PropertySignature */) {
                 // We know we don't have a binding pattern or computed name here
@@ -28457,6 +28580,18 @@ var ts;
                 checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name);
             }
         }
+        function areDeclarationFlagsIdentical(left, right) {
+            if (ts.hasQuestionToken(left) !== ts.hasQuestionToken(right)) {
+                return false;
+            }
+            var interestingFlags = 8 /* Private */ |
+                16 /* Protected */ |
+                256 /* Async */ |
+                128 /* Abstract */ |
+                64 /* Readonly */ |
+                32 /* Static */;
+            return (left.flags & interestingFlags) === (right.flags & interestingFlags);
+        }
         function checkVariableDeclaration(node) {
             checkGrammarVariableDeclaration(node);
             return checkVariableLikeDeclaration(node);
@@ -29150,6 +29285,7 @@ var ts;
             var typeWithThis = getTypeWithThisArgument(type);
             var staticType = getTypeOfSymbol(symbol);
             checkTypeParameterListsIdentical(node, symbol);
+            checkClassForDuplicateDeclarations(node);
             var baseTypeNode = ts.getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
                 var baseTypes = getBaseTypes(type);
@@ -29398,6 +29534,7 @@ var ts;
                         checkIndexConstraints(type);
                     }
                 }
+                checkObjectTypeForDuplicateDeclarations(node);
             }
             ts.forEach(ts.getInterfaceBaseTypeNodes(node), function (heritageElement) {
                 if (!ts.isSupportedExpressionWithTypeArguments(heritageElement)) {
@@ -30241,14 +30378,11 @@ var ts;
         function checkSourceFileWorker(node) {
             var links = getNodeLinks(node);
             if (!(links.flags & 1 /* TypeChecked */)) {
-                // Check whether the file has declared it is the default lib,
-                // and whether the user has specifically chosen to avoid checking it.
-                if (compilerOptions.skipDefaultLibCheck) {
-                    // If the user specified '--noLib' and a file has a '/// <reference no-default-lib="true"/>',
-                    // then we should treat that file as a default lib.
-                    if (node.hasNoDefaultLib) {
-                        return;
-                    }
+                // If skipLibCheck is enabled, skip type checking if file is a declaration file.
+                // If skipDefaultLibCheck is enabled, skip type checking if file contains a
+                // '/// <reference no-default-lib="true"/>' directive.
+                if (compilerOptions.skipLibCheck && node.isDeclarationFile || compilerOptions.skipDefaultLibCheck && node.hasNoDefaultLib) {
+                    return;
                 }
                 // Grammar checking
                 checkGrammarSourceFile(node);
@@ -30665,7 +30799,7 @@ var ts;
                 return symbol && getTypeOfSymbol(symbol);
             }
             if (ts.isBindingPattern(node)) {
-                return getTypeForVariableLikeDeclaration(node.parent);
+                return getTypeForVariableLikeDeclaration(node.parent, /*includeOptionality*/ true);
             }
             if (isInRightSideOfImportOrExportAssignment(node)) {
                 var symbol = getSymbolAtLocation(node);
@@ -31204,7 +31338,7 @@ var ts;
                 if (file.moduleAugmentations.length) {
                     (augmentations || (augmentations = [])).push(file.moduleAugmentations);
                 }
-                if (file.wasReferenced && file.symbol && file.symbol.globalExports) {
+                if (file.symbol && file.symbol.globalExports) {
                     mergeSymbolTable(globals, file.symbol.globalExports);
                 }
             });
@@ -31787,7 +31921,6 @@ var ts;
                     name_20.kind === 140 /* ComputedPropertyName */) {
                     // If the name is not a ComputedPropertyName, the grammar checking will skip it
                     checkGrammarComputedPropertyName(name_20);
-                    return "continue";
                 }
                 if (prop.kind === 254 /* ShorthandPropertyAssignment */ && !inDestructuring && prop.objectAssignmentInitializer) {
                     // having objectAssignmentInitializer is only valid in ObjectAssignmentPattern
@@ -31829,17 +31962,21 @@ var ts;
                 else {
                     ts.Debug.fail("Unexpected syntax kind:" + prop.kind);
                 }
-                if (!ts.hasProperty(seen, name_20.text)) {
-                    seen[name_20.text] = currentKind;
+                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_20);
+                if (effectiveName === undefined) {
+                    return "continue";
+                }
+                if (!ts.hasProperty(seen, effectiveName)) {
+                    seen[effectiveName] = currentKind;
                 }
                 else {
-                    var existingKind = seen[name_20.text];
+                    var existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
-                        return "continue";
+                        grammarErrorOnNode(name_20, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_20));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
-                            seen[name_20.text] = currentKind | existingKind;
+                            seen[effectiveName] = currentKind | existingKind;
                         }
                         else {
                             return { value: grammarErrorOnNode(name_20, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name) };
@@ -41638,8 +41775,8 @@ var ts;
             skipTsx: true,
             traceEnabled: traceEnabled
         };
-        // use typesRoot and fallback to directory that contains tsconfig if typesRoot is not set
-        var rootDir = options.typesRoot || (options.configFilePath ? ts.getDirectoryPath(options.configFilePath) : undefined);
+        // use typesRoot and fallback to directory that contains tsconfig or current directory if typesRoot is not set
+        var rootDir = options.typesRoot || (options.configFilePath ? ts.getDirectoryPath(options.configFilePath) : (host.getCurrentDirectory && host.getCurrentDirectory()));
         if (traceEnabled) {
             if (containingFile === undefined) {
                 if (rootDir === undefined) {
@@ -42229,12 +42366,25 @@ var ts;
                 }
             }
         }
+        function getDefaultTypeDirectiveNames(rootPath) {
+            var localTypes = ts.combinePaths(rootPath, "types");
+            var npmTypes = ts.combinePaths(rootPath, "node_modules/@types");
+            var result = [];
+            if (ts.sys.directoryExists(localTypes)) {
+                result = result.concat(ts.sys.getDirectories(localTypes));
+            }
+            if (ts.sys.directoryExists(npmTypes)) {
+                result = result.concat(ts.sys.getDirectories(npmTypes));
+            }
+            return result;
+        }
         function getDefaultLibLocation() {
             return ts.getDirectoryPath(ts.normalizePath(ts.sys.getExecutingFilePath()));
         }
         var newLine = ts.getNewLineCharacter(options);
         var realpath = ts.sys.realpath && (function (path) { return ts.sys.realpath(path); });
         return {
+            getDefaultTypeDirectiveNames: getDefaultTypeDirectiveNames,
             getSourceFile: getSourceFile,
             getDefaultLibLocation: getDefaultLibLocation,
             getDefaultLibFileName: function (options) { return ts.combinePaths(getDefaultLibLocation(), ts.getDefaultLibFileName(options)); },
@@ -42302,6 +42452,21 @@ var ts;
         }
         return resolutions;
     }
+    function getDefaultTypeDirectiveNames(options, rootFiles, host) {
+        // Use explicit type list from tsconfig.json
+        if (options.types) {
+            return options.types;
+        }
+        // or load all types from the automatic type import fields
+        if (host && host.getDefaultTypeDirectiveNames) {
+            var commonRoot = computeCommonSourceDirectoryOfFilenames(rootFiles, host.getCurrentDirectory(), function (f) { return host.getCanonicalFileName(f); });
+            if (commonRoot) {
+                return host.getDefaultTypeDirectiveNames(commonRoot);
+            }
+        }
+        return undefined;
+    }
+    ts.getDefaultTypeDirectiveNames = getDefaultTypeDirectiveNames;
     function createProgram(rootNames, options, host, oldProgram) {
         var program;
         var files = [];
@@ -42340,14 +42505,15 @@ var ts;
         // used to track cases when two file names differ only in casing
         var filesByNameIgnoreCase = host.useCaseSensitiveFileNames() ? ts.createFileMap(function (fileName) { return fileName.toLowerCase(); }) : undefined;
         if (!tryReuseStructureFromOldProgram()) {
+            ts.forEach(rootNames, function (name) { return processRootFile(name, /*isDefaultLib*/ false); });
             // load type declarations specified via 'types' argument
-            if (options.types && options.types.length) {
-                var resolutions = resolveTypeReferenceDirectiveNamesWorker(options.types, /*containingFile*/ undefined);
-                for (var i = 0; i < options.types.length; i++) {
-                    processTypeReferenceDirective(options.types[i], resolutions[i]);
+            var typeReferences = getDefaultTypeDirectiveNames(options, rootNames, host);
+            if (typeReferences) {
+                var resolutions = resolveTypeReferenceDirectiveNamesWorker(typeReferences, /*containingFile*/ undefined);
+                for (var i = 0; i < typeReferences.length; i++) {
+                    processTypeReferenceDirective(typeReferences[i], resolutions[i]);
                 }
             }
-            ts.forEach(rootNames, function (name) { return processRootFile(name, /*isDefaultLib*/ false); });
             // Do not process the default library if:
             //  - The '--noLib' flag is used.
             //  - A 'no-default-lib' reference comment is encountered in
@@ -42999,9 +43165,6 @@ var ts;
                 if (file_1 && options.forceConsistentCasingInFileNames && ts.getNormalizedAbsolutePath(file_1.fileName, currentDirectory) !== ts.getNormalizedAbsolutePath(fileName, currentDirectory)) {
                     reportFileNamesDifferOnlyInCasingError(fileName, file_1.fileName, refFile, refPos, refEnd);
                 }
-                if (file_1) {
-                    file_1.wasReferenced = file_1.wasReferenced || isReference;
-                }
                 return file_1;
             }
             // We haven't looked for this file, do so now and cache result
@@ -43015,7 +43178,6 @@ var ts;
             });
             filesByName.set(path, file);
             if (file) {
-                file.wasReferenced = file.wasReferenced || isReference;
                 file.path = path;
                 if (host.useCaseSensitiveFileNames()) {
                     // for case-sensitive file systems check if we've already seen some file with similar filename ignoring case
@@ -43129,19 +43291,7 @@ var ts;
                         !options.noResolve &&
                         i < file.imports.length;
                     if (shouldAddFile) {
-                        var importedFile = findSourceFile(resolution.resolvedFileName, ts.toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName), /*isDefaultLib*/ false, /*isReference*/ false, file, ts.skipTrivia(file.text, file.imports[i].pos), file.imports[i].end);
-                        if (importedFile && resolution.isExternalLibraryImport) {
-                            // Since currently irrespective of allowJs, we only look for supportedTypeScript extension external module files,
-                            // this check is ok. Otherwise this would be never true for javascript file
-                            if (!ts.isExternalModule(importedFile) && importedFile.statements.length) {
-                                var start_5 = ts.getTokenPosOfNode(file.imports[i], file);
-                                fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_5, file.imports[i].end - start_5, 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 (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));
-                            }
-                        }
+                        findSourceFile(resolution.resolvedFileName, ts.toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName), /*isDefaultLib*/ false, /*isReference*/ false, file, ts.skipTrivia(file.text, file.imports[i].pos), file.imports[i].end);
                     }
                 }
             }
@@ -43227,7 +43377,7 @@ var ts;
                         }
                     }
                     else {
-                        programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Substututions_for_pattern_0_should_be_an_array, key));
+                        programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Substitutions_for_pattern_0_should_be_an_array, key));
                     }
                 }
             }
@@ -43278,15 +43428,21 @@ var ts;
             else if (firstExternalModuleSourceFile && languageVersion < 2 /* ES6 */ && options.module === ts.ModuleKind.None) {
                 // We cannot use createDiagnosticFromNode because nodes do not have parents yet
                 var span = ts.getErrorSpanForNode(firstExternalModuleSourceFile, firstExternalModuleSourceFile.externalModuleIndicator);
-                programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file));
+                programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_use_imports_exports_or_module_augmentations_when_module_is_none));
             }
             // Cannot specify module gen target of es6 when below es6
             if (options.module === ts.ModuleKind.ES6 && languageVersion < 2 /* ES6 */) {
                 programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Cannot_compile_modules_into_es2015_when_targeting_ES5_or_lower));
             }
             // Cannot specify module gen that isn't amd or system with --out
-            if (outFile && options.module && !(options.module === ts.ModuleKind.AMD || options.module === ts.ModuleKind.System)) {
-                programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Only_amd_and_system_modules_are_supported_alongside_0, options.out ? "out" : "outFile"));
+            if (outFile) {
+                if (options.module && !(options.module === ts.ModuleKind.AMD || options.module === ts.ModuleKind.System)) {
+                    programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Only_amd_and_system_modules_are_supported_alongside_0, options.out ? "out" : "outFile"));
+                }
+                else if (options.module === undefined && firstExternalModuleSourceFile) {
+                    var span = ts.getErrorSpanForNode(firstExternalModuleSourceFile, firstExternalModuleSourceFile.externalModuleIndicator);
+                    programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system, options.out ? "out" : "outFile"));
+                }
             }
             // there has to be common source directory if user specified --outdir || --sourceRoot
             // if user specified --mapRoot, there needs to be common source directory if there would be multiple files being emitted
@@ -43384,6 +43540,11 @@ var ts;
             type: "boolean",
             description: ts.Diagnostics.Print_this_message
         },
+        {
+            name: "help",
+            shortName: "?",
+            type: "boolean"
+        },
         {
             name: "init",
             type: "boolean",
@@ -43486,6 +43647,11 @@ var ts;
             name: "skipDefaultLibCheck",
             type: "boolean"
         },
+        {
+            name: "skipLibCheck",
+            type: "boolean",
+            description: ts.Diagnostics.Skip_type_checking_of_declaration_files
+        },
         {
             name: "out",
             type: "string",
@@ -44315,7 +44481,7 @@ var ts;
 (function (ts) {
     var NavigateTo;
     (function (NavigateTo) {
-        function getNavigateToItems(program, cancellationToken, searchValue, maxResultCount) {
+        function getNavigateToItems(program, checker, cancellationToken, searchValue, maxResultCount) {
             var patternMatcher = ts.createPatternMatcher(searchValue);
             var rawItems = [];
             // This means "compare in a case insensitive manner."
@@ -44354,6 +44520,18 @@ var ts;
                     }
                 }
             });
+            // Remove imports when the imported declaration is already in the list and has the same name.
+            rawItems = ts.filter(rawItems, function (item) {
+                var decl = item.declaration;
+                if (decl.kind === 231 /* ImportClause */ || decl.kind === 234 /* ImportSpecifier */ || decl.kind === 229 /* ImportEqualsDeclaration */) {
+                    var importer = checker.getSymbolAtLocation(decl.name);
+                    var imported = checker.getAliasedSymbol(importer);
+                    return importer.name !== imported.name;
+                }
+                else {
+                    return true;
+                }
+            });
             rawItems.sort(compareNavigateToItems);
             if (maxResultCount !== undefined) {
                 rawItems = rawItems.slice(0, maxResultCount);
@@ -44752,8 +44930,12 @@ var ts;
                         return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.memberSetAccessorElement);
                     case 153 /* IndexSignature */:
                         return createItem(node, "[]", ts.ScriptElementKind.indexSignatureElement);
+                    case 224 /* EnumDeclaration */:
+                        return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.enumElement);
                     case 255 /* EnumMember */:
                         return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.memberVariableElement);
+                    case 222 /* InterfaceDeclaration */:
+                        return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.interfaceElement);
                     case 151 /* CallSignature */:
                         return createItem(node, "()", ts.ScriptElementKind.callSignatureElement);
                     case 152 /* ConstructSignature */:
@@ -45714,7 +45896,7 @@ var ts;
         // To do this, the method will back parse the expression starting at the position required. it will try to parse the current expression as a generic type expression, if it did succeed it 
         // will return the generic identifier that started the expression (e.g. "foo" in "foo<any, |"). It is then up to the caller to ensure that this is a valid generic expression through 
         // looking up the type. The method will also keep track of the parameter index inside the expression.
-        //public static isInPartiallyWrittenTypeArgumentList(syntaxTree: TypeScript.SyntaxTree, position: number): any {
+        // public static isInPartiallyWrittenTypeArgumentList(syntaxTree: TypeScript.SyntaxTree, position: number): any {
         //    let token = Syntax.findTokenOnLeft(syntaxTree.sourceUnit(), position, /*includeSkippedTokens*/ true);
         //    if (token && TypeScript.Syntax.hasAncestorOfKind(token, TypeScript.SyntaxKind.TypeParameterList)) {
         //        // We are in the wrong generic list. bail out
@@ -45810,8 +45992,8 @@ var ts;
         //        token = previousToken(token, /*includeSkippedTokens*/ true);
         //    }
         //    return null;
-        //}
-        //private static moveBackUpTillMatchingTokenKind(token: TypeScript.ISyntaxToken, tokenKind: TypeScript.SyntaxKind, matchingTokenKind: TypeScript.SyntaxKind): TypeScript.ISyntaxToken {
+        // }
+        // private static moveBackUpTillMatchingTokenKind(token: TypeScript.ISyntaxToken, tokenKind: TypeScript.SyntaxKind, matchingTokenKind: TypeScript.SyntaxKind): TypeScript.ISyntaxToken {
         //    if (!token || token.kind() !== tokenKind) {
         //        throw TypeScript.Errors.invalidOperation();
         //    }
@@ -45840,7 +46022,7 @@ var ts;
         //    }
         //    // Did not find matching token
         //    return null;
-        //}
+        // }
         var emptyArray = [];
         var ArgumentListKind;
         (function (ArgumentListKind) {
@@ -46601,7 +46783,7 @@ var ts;
         }
         /// finds last node that is considered as candidate for search (isCandidate(node) === true) starting from 'exclusiveStartPosition'
         function findRightmostChildNodeWithTokens(children, exclusiveStartPosition) {
-            for (var i = exclusiveStartPosition - 1; i >= 0; --i) {
+            for (var i = exclusiveStartPosition - 1; i >= 0; i--) {
                 if (nodeHasTokens(children[i])) {
                     return children[i];
                 }
@@ -47337,12 +47519,11 @@ var ts;
                 if (!isStarted) {
                     scanner.scan();
                 }
-                var t;
                 var pos = scanner.getStartPos();
                 // Read leading trivia and token
                 while (pos < endPos) {
-                    var t_1 = scanner.getToken();
-                    if (!ts.isTrivia(t_1)) {
+                    var t = scanner.getToken();
+                    if (!ts.isTrivia(t)) {
                         break;
                     }
                     // consume leading trivia
@@ -47350,7 +47531,7 @@ var ts;
                     var item = {
                         pos: pos,
                         end: scanner.getStartPos(),
-                        kind: t_1
+                        kind: t
                     };
                     pos = scanner.getStartPos();
                     if (!leadingTrivia) {
@@ -47690,6 +47871,7 @@ var ts;
     })(formatting = ts.formatting || (ts.formatting = {}));
 })(ts || (ts = {}));
 ///<reference path='references.ts' />
+/* tslint:disable:no-null-keyword */
 /* @internal */
 var ts;
 (function (ts) {
@@ -47951,7 +48133,7 @@ var ts;
                 this.SpaceAfterKeywordInControl = new formatting.Rule(formatting.RuleDescriptor.create2(formatting.Shared.TokenRange.Keywords, 17 /* OpenParenToken */), formatting.RuleOperation.create2(new formatting.RuleOperationContext(Rules.IsControlDeclContext), 2 /* Space */));
                 this.NoSpaceAfterKeywordInControl = new formatting.Rule(formatting.RuleDescriptor.create2(formatting.Shared.TokenRange.Keywords, 17 /* OpenParenToken */), formatting.RuleOperation.create2(new formatting.RuleOperationContext(Rules.IsControlDeclContext), 8 /* Delete */));
                 // Open Brace braces after function
-                //TypeScript: Function can have return types, which can be made of tons of different token kinds
+                // TypeScript: Function can have return types, which can be made of tons of different token kinds
                 this.NewLineBeforeOpenBraceInFunction = new formatting.Rule(formatting.RuleDescriptor.create2(this.FunctionOpenBraceLeftTokenRange, 15 /* OpenBraceToken */), formatting.RuleOperation.create2(new formatting.RuleOperationContext(Rules.IsFunctionDeclContext, Rules.IsBeforeMultilineBlockContext), 4 /* NewLine */), 1 /* CanDeleteNewLines */);
                 // Open Brace braces after TypeScript module/class/interface
                 this.NewLineBeforeOpenBraceInTypeScriptDeclWithBlock = new formatting.Rule(formatting.RuleDescriptor.create2(this.TypeScriptOpenBraceLeftTokenRange, 15 /* OpenBraceToken */), formatting.RuleOperation.create2(new formatting.RuleOperationContext(Rules.IsTypeScriptDeclWithBlockContext, Rules.IsBeforeMultilineBlockContext), 4 /* NewLine */), 1 /* CanDeleteNewLines */);
@@ -48092,17 +48274,17 @@ var ts;
                     case 220 /* FunctionDeclaration */:
                     case 147 /* MethodDeclaration */:
                     case 146 /* MethodSignature */:
-                    //case SyntaxKind.MemberFunctionDeclaration:
+                    // case SyntaxKind.MemberFunctionDeclaration:
                     case 149 /* GetAccessor */:
                     case 150 /* SetAccessor */:
-                    ///case SyntaxKind.MethodSignature:
+                    // case SyntaxKind.MethodSignature:
                     case 151 /* CallSignature */:
                     case 179 /* FunctionExpression */:
                     case 148 /* Constructor */:
                     case 180 /* ArrowFunction */:
-                    //case SyntaxKind.ConstructorDeclaration:
-                    //case SyntaxKind.SimpleArrowFunctionExpression:
-                    //case SyntaxKind.ParenthesizedArrowFunctionExpression:
+                    // case SyntaxKind.ConstructorDeclaration:
+                    // case SyntaxKind.SimpleArrowFunctionExpression:
+                    // case SyntaxKind.ParenthesizedArrowFunctionExpression:
                     case 222 /* InterfaceDeclaration */:
                         return true;
                 }
@@ -48254,6 +48436,7 @@ var ts;
     })(formatting = ts.formatting || (ts.formatting = {}));
 })(ts || (ts = {}));
 ///<reference path='references.ts' />
+/* tslint:disable:no-null-keyword */
 /* @internal */
 var ts;
 (function (ts) {
@@ -48271,9 +48454,9 @@ var ts;
             };
             RulesMap.prototype.Initialize = function (rules) {
                 this.mapRowLength = 138 /* LastToken */ + 1;
-                this.map = new Array(this.mapRowLength * this.mapRowLength); //new Array<RulesBucket>(this.mapRowLength * this.mapRowLength);
+                this.map = new Array(this.mapRowLength * this.mapRowLength); // new Array<RulesBucket>(this.mapRowLength * this.mapRowLength);
                 // This array is used only during construction of the rulesbucket in the map
-                var rulesBucketConstructionStateList = new Array(this.map.length); //new Array<RulesBucketConstructionState>(this.map.length);
+                var rulesBucketConstructionStateList = new Array(this.map.length); // new Array<RulesBucketConstructionState>(this.map.length);
                 this.FillRules(rules, rulesBucketConstructionStateList);
                 return this.map;
             };
@@ -48285,7 +48468,7 @@ var ts;
             };
             RulesMap.prototype.GetRuleBucketIndex = function (row, column) {
                 var rulesBucketIndex = (row * this.mapRowLength) + column;
-                //Debug.Assert(rulesBucketIndex < this.map.Length, "Trying to access an index outside the array.");
+                // Debug.Assert(rulesBucketIndex < this.map.Length, "Trying to access an index outside the array.");
                 return rulesBucketIndex;
             };
             RulesMap.prototype.FillRule = function (rule, rulesBucketConstructionStateList) {
@@ -48537,6 +48720,7 @@ var ts;
 ///<reference path='rulesMap.ts' />
 ///<reference path='tokenRange.ts' /> 
 /// <reference path="references.ts"/>
+/* tslint:disable:no-null-keyword */
 /* @internal */
 var ts;
 (function (ts) {
@@ -49058,7 +49242,7 @@ var ts;
                 // if there are any tokens that logically belong to node and interleave child nodes
                 // such tokens will be consumed in processChildNode for for the child that follows them
                 ts.forEachChild(node, function (child) {
-                    processChildNode(child, /*inheritedIndentation*/ -1 /* Unknown */, node, nodeDynamicIndentation, nodeStartLine, undecoratedNodeStartLine, /*isListElement*/ false);
+                    processChildNode(child, /*inheritedIndentation*/ -1 /* Unknown */, node, nodeDynamicIndentation, nodeStartLine, undecoratedNodeStartLine, /*isListItem*/ false);
                 }, function (nodes) {
                     processChildNodes(nodes, node, nodeStartLine, nodeDynamicIndentation);
                 });
@@ -49149,7 +49333,7 @@ var ts;
                     var inheritedIndentation = -1 /* Unknown */;
                     for (var i = 0; i < nodes.length; i++) {
                         var child = nodes[i];
-                        inheritedIndentation = processChildNode(child, inheritedIndentation, node, listDynamicIndentation, startLine, startLine, /*isListElement*/ true, /*isFirstListItem*/ i === 0);
+                        inheritedIndentation = processChildNode(child, inheritedIndentation, node, listDynamicIndentation, startLine, startLine, /*isListItem*/ true, /*isFirstListItem*/ i === 0);
                     }
                     if (listEndToken !== 0 /* Unknown */) {
                         if (formattingScanner.isOnToken()) {
@@ -49279,7 +49463,7 @@ var ts;
                         // Handle the case where the next line is moved to be the end of this line.
                         // In this case we don't indent the next line in the next pass.
                         if (currentParent.getStart(sourceFile) === currentItem.pos) {
-                            dynamicIndentation.recomputeIndentation(/*lineAdded*/ false);
+                            dynamicIndentation.recomputeIndentation(/*lineAddedByFormatting*/ false);
                         }
                     }
                     else if (rule.Operation.Action & 4 /* NewLine */ && currentStartLine === previousStartLine) {
@@ -49288,7 +49472,7 @@ var ts;
                         // In this case we indent token2 in the next pass but we set
                         // sameLineIndent flag to notify the indenter that the indentation is within the line.
                         if (currentParent.getStart(sourceFile) === currentItem.pos) {
-                            dynamicIndentation.recomputeIndentation(/*lineAdded*/ true);
+                            dynamicIndentation.recomputeIndentation(/*lineAddedByFormatting*/ true);
                         }
                     }
                     // We need to trim trailing whitespace between the tokens if they were on different lines, and no rule was applied to put them on the same line
@@ -49336,7 +49520,7 @@ var ts;
                 else {
                     parts = [];
                     var startPos = commentRange.pos;
-                    for (var line = startLine; line < endLine; ++line) {
+                    for (var line = startLine; line < endLine; line++) {
                         var endOfLine = ts.getEndLinePosition(line, sourceFile);
                         parts.push({ pos: startPos, end: endOfLine });
                         startPos = ts.getStartPositionOfLine(line + 1, sourceFile);
@@ -49355,7 +49539,7 @@ var ts;
                 }
                 // shift all parts on the delta size
                 var delta = indentation - nonWhitespaceColumnInFirstPart.column;
-                for (var i = startIndex, len = parts.length; i < len; ++i, ++startLine) {
+                for (var i = startIndex, len = parts.length; i < len; i++, startLine++) {
                     var startLinePos_1 = ts.getStartPositionOfLine(startLine, sourceFile);
                     var nonWhitespaceCharacterAndColumn = i === 0
                         ? nonWhitespaceColumnInFirstPart
@@ -49371,7 +49555,7 @@ var ts;
                 }
             }
             function trimTrailingWhitespacesForLines(line1, line2, range) {
-                for (var line = line1; line < line2; ++line) {
+                for (var line = line1; line < line2; line++) {
                     var lineStartPosition = ts.getStartPositionOfLine(line, sourceFile);
                     var lineEndPosition = ts.getEndLinePosition(line, sourceFile);
                     // do not trim whitespaces in comments or template expression
@@ -49422,7 +49606,6 @@ var ts;
                 }
             }
             function applyRuleEdits(rule, previousRange, previousStartLine, currentRange, currentStartLine) {
-                var between;
                 switch (rule.Operation.Action) {
                     case 1 /* Ignore */:
                         // no action required
@@ -49459,14 +49642,6 @@ var ts;
                 }
             }
         }
-        function isSomeBlock(kind) {
-            switch (kind) {
-                case 199 /* Block */:
-                case 226 /* ModuleBlock */:
-                    return true;
-            }
-            return false;
-        }
         function getOpenTokenForList(node, list) {
             switch (node.kind) {
                 case 148 /* Constructor */:
@@ -49525,7 +49700,7 @@ var ts;
                     internedTabsIndentation = [];
                 }
                 if (internedTabsIndentation[tabs] === undefined) {
-                    internedTabsIndentation[tabs] = tabString = repeat('\t', tabs);
+                    internedTabsIndentation[tabs] = tabString = repeat("\t", tabs);
                 }
                 else {
                     tabString = internedTabsIndentation[tabs];
@@ -49550,7 +49725,7 @@ var ts;
             }
             function repeat(value, count) {
                 var s = "";
-                for (var i = 0; i < count; ++i) {
+                for (var i = 0; i < count; i++) {
                     s += value;
                 }
                 return s;
@@ -49866,7 +50041,7 @@ var ts;
                 // walk toward the start of the list starting from current node and check if the line is the same for all items.
                 // if end line for item [i - 1] differs from the start line for item [i] - find column of the first non-whitespace character on the line of item [i]
                 var lineAndCharacter = getStartLineAndCharacterForNode(node, sourceFile);
-                for (var i = index - 1; i >= 0; --i) {
+                for (var i = index - 1; i >= 0; i--) {
                     if (list[i].kind === 24 /* CommaToken */) {
                         continue;
                     }
@@ -49893,7 +50068,7 @@ var ts;
             function findFirstNonWhitespaceCharacterAndColumn(startPos, endPos, sourceFile, options) {
                 var character = 0;
                 var column = 0;
-                for (var pos = startPos; pos < endPos; ++pos) {
+                for (var pos = startPos; pos < endPos; pos++) {
                     var ch = sourceFile.text.charCodeAt(pos);
                     if (!ts.isWhiteSpace(ch)) {
                         break;
@@ -49987,7 +50162,7 @@ var ts;
             Function returns true when the parent node should indent the given child by an explicit rule
             */
             function shouldIndentChildNode(parent, child) {
-                return nodeContentIsAlwaysIndented(parent.kind) || nodeWillIndentChild(parent, child, false);
+                return nodeContentIsAlwaysIndented(parent.kind) || nodeWillIndentChild(parent, child, /*indentByDefault*/ false);
             }
             SmartIndenter.shouldIndentChildNode = shouldIndentChildNode;
         })(SmartIndenter = formatting.SmartIndenter || (formatting.SmartIndenter = {}));
@@ -50809,49 +50984,55 @@ var ts;
     (function (ScriptElementKind) {
         ScriptElementKind.unknown = "";
         ScriptElementKind.warning = "warning";
-        // predefined type (void) or keyword (class)
+        /** predefined type (void) or keyword (class) */
         ScriptElementKind.keyword = "keyword";
-        // top level script node
+        /** top level script node */
         ScriptElementKind.scriptElement = "script";
-        // module foo {}
+        /** module foo {} */
         ScriptElementKind.moduleElement = "module";
-        // class X {}
+        /** class X {} */
         ScriptElementKind.classElement = "class";
-        // var x = class X {}
+        /** var x = class X {} */
         ScriptElementKind.localClassElement = "local class";
-        // interface Y {}
+        /** interface Y {} */
         ScriptElementKind.interfaceElement = "interface";
-        // type T = ...
+        /** type T = ... */
         ScriptElementKind.typeElement = "type";
-        // enum E
+        /** enum E */
         ScriptElementKind.enumElement = "enum";
-        // Inside module and script only
-        // const v = ..
+        /**
+         * Inside module and script only
+         * const v = ..
+         */
         ScriptElementKind.variableElement = "var";
-        // Inside function
+        /** Inside function */
         ScriptElementKind.localVariableElement = "local var";
-        // Inside module and script only
-        // function f() { }
+        /**
+         * Inside module and script only
+         * function f() { }
+         */
         ScriptElementKind.functionElement = "function";
-        // Inside function
+        /** Inside function */
         ScriptElementKind.localFunctionElement = "local function";
-        // class X { [public|private]* foo() {} }
+        /** class X { [public|private]* foo() {} } */
         ScriptElementKind.memberFunctionElement = "method";
-        // class X { [public|private]* [get|set] foo:number; }
+        /** class X { [public|private]* [get|set] foo:number; } */
         ScriptElementKind.memberGetAccessorElement = "getter";
         ScriptElementKind.memberSetAccessorElement = "setter";
-        // class X { [public|private]* foo:number; }
-        // interface Y { foo:number; }
+        /**
+         * class X { [public|private]* foo:number; }
+         * interface Y { foo:number; }
+         */
         ScriptElementKind.memberVariableElement = "property";
-        // class X { constructor() { } }
+        /** class X { constructor() { } } */
         ScriptElementKind.constructorImplementationElement = "constructor";
-        // interface Y { ():number; }
+        /** interface Y { ():number; } */
         ScriptElementKind.callSignatureElement = "call";
-        // interface Y { []:number; }
+        /** interface Y { []:number; } */
         ScriptElementKind.indexSignatureElement = "index";
-        // interface Y { new():Y; }
+        /** interface Y { new():Y; } */
         ScriptElementKind.constructSignatureElement = "construct";
-        // function foo(*Y*: string)
+        /** function foo(*Y*: string) */
         ScriptElementKind.parameterElement = "parameter";
         ScriptElementKind.typeParameterElement = "type parameter";
         ScriptElementKind.primitiveType = "primitive type";
@@ -52236,9 +52417,9 @@ 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_6 = new Date().getTime();
+                var start_5 = new Date().getTime();
                 contextToken = ts.findPrecedingToken(contextToken.getFullStart(), sourceFile);
-                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_6));
+                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_5));
             }
             // Find the node where completion is requested on.
             // Also determine whether we are trying to complete with members of that node
@@ -52518,13 +52699,13 @@ var ts;
                     || contextToken.kind === 166 /* StringLiteralType */
                     || contextToken.kind === 10 /* RegularExpressionLiteral */
                     || ts.isTemplateLiteralKind(contextToken.kind)) {
-                    var start_7 = contextToken.getStart();
+                    var start_6 = 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_7 < position && position < end) {
+                    if (start_6 < position && position < end) {
                         return true;
                     }
                     if (position === end) {
@@ -53759,8 +53940,7 @@ var ts;
         }
         function getDocumentHighlights(fileName, position, filesToSearch) {
             synchronizeHostData();
-            filesToSearch = ts.map(filesToSearch, ts.normalizeSlashes);
-            var sourceFilesToSearch = ts.filter(program.getSourceFiles(), function (f) { return ts.contains(filesToSearch, f.fileName); });
+            var sourceFilesToSearch = ts.map(filesToSearch, function (f) { return program.getSourceFile(f); });
             var sourceFile = getValidSourceFile(fileName);
             var node = ts.getTouchingWord(sourceFile, position);
             if (!node) {
@@ -55150,7 +55330,8 @@ var ts;
         /// NavigateTo
         function getNavigateToItems(searchValue, maxResultCount) {
             synchronizeHostData();
-            return ts.NavigateTo.getNavigateToItems(program, cancellationToken, searchValue, maxResultCount);
+            var checker = getProgram().getTypeChecker();
+            return ts.NavigateTo.getNavigateToItems(program, checker, cancellationToken, searchValue, maxResultCount);
         }
         function getEmitOutput(fileName) {
             synchronizeHostData();
@@ -57559,6 +57740,9 @@ var ts;
         LanguageServiceShimHostAdapter.prototype.getCurrentDirectory = function () {
             return this.shimHost.getCurrentDirectory();
         };
+        LanguageServiceShimHostAdapter.prototype.getDirectories = function (path) {
+            return this.shimHost.getDirectories(path);
+        };
         LanguageServiceShimHostAdapter.prototype.getDefaultLibFileName = function (options) {
             return this.shimHost.getDefaultLibFileName(JSON.stringify(options));
         };
diff --git a/lib/typescriptServices.d.ts b/lib/typescriptServices.d.ts
index cd459201d8b..67530e211bc 100644
--- a/lib/typescriptServices.d.ts
+++ b/lib/typescriptServices.d.ts
@@ -261,7 +261,7 @@ declare namespace ts {
         ModuleDeclaration = 225,
         ModuleBlock = 226,
         CaseBlock = 227,
-        GlobalModuleExportDeclaration = 228,
+        NamespaceExportDeclaration = 228,
         ImportEqualsDeclaration = 229,
         ImportDeclaration = 230,
         ImportClause = 231,
@@ -934,7 +934,7 @@ declare namespace ts {
     interface NamespaceImport extends Declaration {
         name: Identifier;
     }
-    interface GlobalModuleExportDeclaration extends DeclarationStatement {
+    interface NamespaceExportDeclaration extends DeclarationStatement {
         name: Identifier;
         moduleReference: LiteralLikeNode;
     }
@@ -1329,7 +1329,7 @@ declare namespace ts {
         FunctionScopedVariableExcludes = 107454,
         BlockScopedVariableExcludes = 107455,
         ParameterExcludes = 107455,
-        PropertyExcludes = 107455,
+        PropertyExcludes = 0,
         EnumMemberExcludes = 107455,
         FunctionExcludes = 106927,
         ClassExcludes = 899519,
@@ -1554,6 +1554,7 @@ declare namespace ts {
         allowJs?: boolean;
         noImplicitUseStrict?: boolean;
         strictNullChecks?: boolean;
+        skipLibCheck?: boolean;
         listEmittedFiles?: boolean;
         lib?: string[];
         types?: string[];
@@ -1627,6 +1628,7 @@ declare namespace ts {
         trace?(s: string): void;
         directoryExists?(directoryName: string): boolean;
         realpath?(path: string): string;
+        getCurrentDirectory?(): string;
     }
     interface ResolvedModule {
         resolvedFileName: string;
@@ -1650,6 +1652,7 @@ declare namespace ts {
         getCancellationToken?(): CancellationToken;
         getDefaultLibFileName(options: CompilerOptions): string;
         getDefaultLibLocation?(): string;
+        getDefaultTypeDirectiveNames?(rootPath: string): string[];
         writeFile: WriteFileCallback;
         getCurrentDirectory(): string;
         getCanonicalFileName(fileName: string): string;
@@ -1693,6 +1696,7 @@ declare namespace ts {
         createDirectory(path: string): void;
         getExecutingFilePath(): string;
         getCurrentDirectory(): string;
+        getDirectories(path: string): string[];
         readDirectory(path: string, extension?: string, exclude?: string[]): string[];
         getModifiedTime?(path: string): Date;
         createHash?(data: string): string;
@@ -1812,6 +1816,7 @@ declare namespace ts {
     function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost;
     function getPreEmitDiagnostics(program: Program, sourceFile?: SourceFile, cancellationToken?: CancellationToken): Diagnostic[];
     function flattenDiagnosticMessageText(messageText: string | DiagnosticMessageChain, newLine: string): string;
+    function getDefaultTypeDirectiveNames(options: CompilerOptions, rootFiles: string[], host: CompilerHost): string[];
     function createProgram(rootNames: string[], options: CompilerOptions, host?: CompilerHost, oldProgram?: Program): Program;
 }
 declare namespace ts {
@@ -2345,26 +2350,55 @@ declare namespace ts {
     namespace ScriptElementKind {
         const unknown: string;
         const warning: string;
+        /** predefined type (void) or keyword (class) */
         const keyword: string;
+        /** top level script node */
         const scriptElement: string;
+        /** module foo {} */
         const moduleElement: string;
+        /** class X {} */
         const classElement: string;
+        /** var x = class X {} */
         const localClassElement: string;
+        /** interface Y {} */
         const interfaceElement: string;
+        /** type T = ... */
         const typeElement: string;
+        /** enum E */
         const enumElement: string;
+        /**
+         * Inside module and script only
+         * const v = ..
+         */
         const variableElement: string;
+        /** Inside function */
         const localVariableElement: string;
+        /**
+         * Inside module and script only
+         * function f() { }
+         */
         const functionElement: string;
+        /** Inside function */
         const localFunctionElement: string;
+        /** class X { [public|private]* foo() {} } */
         const memberFunctionElement: string;
+        /** class X { [public|private]* [get|set] foo:number; } */
         const memberGetAccessorElement: string;
         const memberSetAccessorElement: string;
+        /**
+         * class X { [public|private]* foo:number; }
+         * interface Y { foo:number; }
+         */
         const memberVariableElement: string;
+        /** class X { constructor() { } } */
         const constructorImplementationElement: string;
+        /** interface Y { ():number; } */
         const callSignatureElement: string;
+        /** interface Y { []:number; } */
         const indexSignatureElement: string;
+        /** interface Y { new():Y; } */
         const constructSignatureElement: string;
+        /** function foo(*Y*: string) */
         const parameterElement: string;
         const typeParameterElement: string;
         const primitiveType: string;
diff --git a/lib/typescriptServices.js b/lib/typescriptServices.js
index e78eda7b0bb..19fffd35501 100644
--- a/lib/typescriptServices.js
+++ b/lib/typescriptServices.js
@@ -271,7 +271,7 @@ var ts;
         SyntaxKind[SyntaxKind["ModuleDeclaration"] = 225] = "ModuleDeclaration";
         SyntaxKind[SyntaxKind["ModuleBlock"] = 226] = "ModuleBlock";
         SyntaxKind[SyntaxKind["CaseBlock"] = 227] = "CaseBlock";
-        SyntaxKind[SyntaxKind["GlobalModuleExportDeclaration"] = 228] = "GlobalModuleExportDeclaration";
+        SyntaxKind[SyntaxKind["NamespaceExportDeclaration"] = 228] = "NamespaceExportDeclaration";
         SyntaxKind[SyntaxKind["ImportEqualsDeclaration"] = 229] = "ImportEqualsDeclaration";
         SyntaxKind[SyntaxKind["ImportDeclaration"] = 230] = "ImportDeclaration";
         SyntaxKind[SyntaxKind["ImportClause"] = 231] = "ImportClause";
@@ -561,7 +561,7 @@ var ts;
         // they can not merge with anything in the value space
         SymbolFlags[SymbolFlags["BlockScopedVariableExcludes"] = 107455] = "BlockScopedVariableExcludes";
         SymbolFlags[SymbolFlags["ParameterExcludes"] = 107455] = "ParameterExcludes";
-        SymbolFlags[SymbolFlags["PropertyExcludes"] = 107455] = "PropertyExcludes";
+        SymbolFlags[SymbolFlags["PropertyExcludes"] = 0] = "PropertyExcludes";
         SymbolFlags[SymbolFlags["EnumMemberExcludes"] = 107455] = "EnumMemberExcludes";
         SymbolFlags[SymbolFlags["FunctionExcludes"] = 106927] = "FunctionExcludes";
         SymbolFlags[SymbolFlags["ClassExcludes"] = 899519] = "ClassExcludes";
@@ -1841,6 +1841,10 @@ var ts;
                 }
                 return result.sort();
             }
+            function getDirectories(path) {
+                var folder = fso.GetFolder(path);
+                return getNames(folder.subfolders);
+            }
             function readDirectory(path, extension, exclude) {
                 var result = [];
                 exclude = ts.map(exclude, function (s) { return getCanonicalPath(ts.combinePaths(path, s)); });
@@ -1895,6 +1899,7 @@ var ts;
                 getCurrentDirectory: function () {
                     return new ActiveXObject("WScript.Shell").CurrentDirectory;
                 },
+                getDirectories: getDirectories,
                 readDirectory: readDirectory,
                 exit: function (exitCode) {
                     try {
@@ -2057,6 +2062,9 @@ var ts;
             function directoryExists(path) {
                 return fileSystemEntryExists(path, 1 /* Directory */);
             }
+            function getDirectories(path) {
+                return ts.filter(_fs.readdirSync(path), function (p) { return fileSystemEntryExists(ts.combinePaths(path, p), 1 /* Directory */); });
+            }
             function readDirectory(path, extension, exclude) {
                 var result = [];
                 exclude = ts.map(exclude, function (s) { return getCanonicalPath(ts.combinePaths(path, s)); });
@@ -2157,6 +2165,7 @@ var ts;
                 getCurrentDirectory: function () {
                     return process.cwd();
                 },
+                getDirectories: getDirectories,
                 readDirectory: readDirectory,
                 getModifiedTime: function (path) {
                     try {
@@ -2209,6 +2218,7 @@ var ts;
                 createDirectory: ChakraHost.createDirectory,
                 getExecutingFilePath: function () { return ChakraHost.executingFile; },
                 getCurrentDirectory: function () { return ChakraHost.currentDirectory; },
+                getDirectories: ChakraHost.getDirectories,
                 readDirectory: ChakraHost.readDirectory,
                 exit: ChakraHost.quit,
                 realpath: realpath
@@ -2347,7 +2357,7 @@ var ts;
         or_expected: { code: 1144, category: ts.DiagnosticCategory.Error, key: "or_expected_1144", message: "'{' or ';' expected." },
         Declaration_expected: { code: 1146, category: ts.DiagnosticCategory.Error, key: "Declaration_expected_1146", message: "Declaration expected." },
         Import_declarations_in_a_namespace_cannot_reference_a_module: { code: 1147, category: ts.DiagnosticCategory.Error, key: "Import_declarations_in_a_namespace_cannot_reference_a_module_1147", message: "Import declarations in a namespace cannot reference a module." },
-        Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file: { code: 1148, category: ts.DiagnosticCategory.Error, key: "Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting__1148", message: "Cannot compile modules unless the '--module' flag is provided with a valid module type. Consider setting the 'module' compiler option in a 'tsconfig.json' file." },
+        Cannot_use_imports_exports_or_module_augmentations_when_module_is_none: { code: 1148, category: ts.DiagnosticCategory.Error, key: "Cannot_use_imports_exports_or_module_augmentations_when_module_is_none_1148", message: "Cannot use imports, exports, or module augmentations when '--module' is 'none'." },
         File_name_0_differs_from_already_included_file_name_1_only_in_casing: { code: 1149, category: ts.DiagnosticCategory.Error, key: "File_name_0_differs_from_already_included_file_name_1_only_in_casing_1149", message: "File name '{0}' differs from already included file name '{1}' only in casing" },
         new_T_cannot_be_used_to_create_an_array_Use_new_Array_T_instead: { code: 1150, category: ts.DiagnosticCategory.Error, key: "new_T_cannot_be_used_to_create_an_array_Use_new_Array_T_instead_1150", message: "'new T[]' cannot be used to create an array. Use 'new Array<T>()' instead." },
         const_declarations_must_be_initialized: { code: 1155, category: ts.DiagnosticCategory.Error, key: "const_declarations_must_be_initialized_1155", message: "'const' declarations must be initialized" },
@@ -2717,6 +2727,8 @@ var ts;
         this_implicitly_has_type_any_because_it_does_not_have_a_type_annotation: { code: 2683, category: ts.DiagnosticCategory.Error, key: "this_implicitly_has_type_any_because_it_does_not_have_a_type_annotation_2683", message: "'this' implicitly has type 'any' because it does not have a type annotation." },
         The_this_context_of_type_0_is_not_assignable_to_method_s_this_of_type_1: { code: 2684, category: ts.DiagnosticCategory.Error, key: "The_this_context_of_type_0_is_not_assignable_to_method_s_this_of_type_1_2684", message: "The 'this' context of type '{0}' is not assignable to method's 'this' of type '{1}'." },
         The_this_types_of_each_signature_are_incompatible: { code: 2685, category: ts.DiagnosticCategory.Error, key: "The_this_types_of_each_signature_are_incompatible_2685", message: "The 'this' types of each signature are incompatible." },
+        Identifier_0_must_be_imported_from_a_module: { code: 2686, category: ts.DiagnosticCategory.Error, key: "Identifier_0_must_be_imported_from_a_module_2686", message: "Identifier '{0}' must be imported from a module" },
+        All_declarations_of_0_must_have_identical_modifiers: { code: 2687, category: ts.DiagnosticCategory.Error, key: "All_declarations_of_0_must_have_identical_modifiers_2687", message: "All declarations of '{0}' must have identical modifiers." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: ts.DiagnosticCategory.Error, key: "Import_declaration_0_is_using_private_name_1_4000", message: "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_4002", message: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
         Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1: { code: 4004, category: ts.DiagnosticCategory.Error, key: "Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1_4004", message: "Type parameter '{0}' of exported interface has or is using private name '{1}'." },
@@ -2810,7 +2822,7 @@ var ts;
         Option_paths_cannot_be_used_without_specifying_baseUrl_option: { code: 5060, category: ts.DiagnosticCategory.Error, key: "Option_paths_cannot_be_used_without_specifying_baseUrl_option_5060", message: "Option 'paths' cannot be used without specifying '--baseUrl' option." },
         Pattern_0_can_have_at_most_one_Asterisk_character: { code: 5061, category: ts.DiagnosticCategory.Error, key: "Pattern_0_can_have_at_most_one_Asterisk_character_5061", message: "Pattern '{0}' can have at most one '*' character" },
         Substitution_0_in_pattern_1_in_can_have_at_most_one_Asterisk_character: { code: 5062, category: ts.DiagnosticCategory.Error, key: "Substitution_0_in_pattern_1_in_can_have_at_most_one_Asterisk_character_5062", message: "Substitution '{0}' in pattern '{1}' in can have at most one '*' character" },
-        Substututions_for_pattern_0_should_be_an_array: { code: 5063, category: ts.DiagnosticCategory.Error, key: "Substututions_for_pattern_0_should_be_an_array_5063", message: "Substututions for pattern '{0}' should be an array." },
+        Substitutions_for_pattern_0_should_be_an_array: { code: 5063, category: ts.DiagnosticCategory.Error, key: "Substitutions_for_pattern_0_should_be_an_array_5063", message: "Substitutions for pattern '{0}' should be an array." },
         Substitution_0_for_pattern_1_has_incorrect_type_expected_string_got_2: { code: 5064, category: ts.DiagnosticCategory.Error, key: "Substitution_0_for_pattern_1_has_incorrect_type_expected_string_got_2_5064", message: "Substitution '{0}' for pattern '{1}' has incorrect type, expected 'string', got '{2}'." },
         Concatenate_and_emit_output_to_single_file: { code: 6001, category: ts.DiagnosticCategory.Message, key: "Concatenate_and_emit_output_to_single_file_6001", message: "Concatenate and emit output to single file." },
         Generates_corresponding_d_ts_file: { code: 6002, category: ts.DiagnosticCategory.Message, key: "Generates_corresponding_d_ts_file_6002", message: "Generates corresponding '.d.ts' file." },
@@ -2823,6 +2835,7 @@ var ts;
         Do_not_emit_comments_to_output: { code: 6009, category: ts.DiagnosticCategory.Message, key: "Do_not_emit_comments_to_output_6009", message: "Do not emit comments to output." },
         Do_not_emit_outputs: { code: 6010, category: ts.DiagnosticCategory.Message, key: "Do_not_emit_outputs_6010", message: "Do not emit outputs." },
         Allow_default_imports_from_modules_with_no_default_export_This_does_not_affect_code_emit_just_typechecking: { code: 6011, category: ts.DiagnosticCategory.Message, key: "Allow_default_imports_from_modules_with_no_default_export_This_does_not_affect_code_emit_just_typech_6011", message: "Allow default imports from modules with no default export. This does not affect code emit, just typechecking." },
+        Skip_type_checking_of_declaration_files: { code: 6012, category: ts.DiagnosticCategory.Message, key: "Skip_type_checking_of_declaration_files_6012", message: "Skip type checking of declaration files." },
         Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015: { code: 6015, category: ts.DiagnosticCategory.Message, key: "Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015_6015", message: "Specify ECMAScript target version: 'ES3' (default), 'ES5', or 'ES2015'" },
         Specify_module_code_generation_Colon_commonjs_amd_system_umd_or_es2015: { code: 6016, category: ts.DiagnosticCategory.Message, key: "Specify_module_code_generation_Colon_commonjs_amd_system_umd_or_es2015_6016", message: "Specify module code generation: 'commonjs', 'amd', 'system', 'umd' or 'es2015'" },
         Print_this_message: { code: 6017, category: ts.DiagnosticCategory.Message, key: "Print_this_message_6017", message: "Print this message." },
@@ -2924,6 +2937,7 @@ var ts;
         Resolving_type_reference_directive_0_containing_file_not_set_root_directory_not_set: { code: 6128, category: ts.DiagnosticCategory.Message, key: "Resolving_type_reference_directive_0_containing_file_not_set_root_directory_not_set_6128", message: "======== Resolving type reference directive '{0}', containing file not set, root directory not set. ========" },
         The_config_file_0_found_doesn_t_contain_any_source_files: { code: 6129, category: ts.DiagnosticCategory.Error, key: "The_config_file_0_found_doesn_t_contain_any_source_files_6129", message: "The config file '{0}' found doesn't contain any source files." },
         Resolving_real_path_for_0_result_1: { code: 6130, category: ts.DiagnosticCategory.Message, key: "Resolving_real_path_for_0_result_1_6130", message: "Resolving real path for '{0}', result '{1}'" },
+        Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system: { code: 6131, category: ts.DiagnosticCategory.Error, key: "Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system_6131", message: "Cannot compile modules using option '{0}' unless the '--module' flag is 'amd' or 'system'." },
         Variable_0_implicitly_has_an_1_type: { code: 7005, category: ts.DiagnosticCategory.Error, key: "Variable_0_implicitly_has_an_1_type_7005", message: "Variable '{0}' implicitly has an '{1}' type." },
         Parameter_0_implicitly_has_an_1_type: { code: 7006, category: ts.DiagnosticCategory.Error, key: "Parameter_0_implicitly_has_an_1_type_7006", message: "Parameter '{0}' implicitly has an '{1}' type." },
         Member_0_implicitly_has_an_1_type: { code: 7008, category: ts.DiagnosticCategory.Error, key: "Member_0_implicitly_has_an_1_type_7008", message: "Member '{0}' implicitly has an '{1}' type." },
@@ -6172,7 +6186,7 @@ var ts;
     // export default ...
     function isAliasSymbolDeclaration(node) {
         return node.kind === 229 /* ImportEqualsDeclaration */ ||
-            node.kind === 228 /* GlobalModuleExportDeclaration */ ||
+            node.kind === 228 /* NamespaceExportDeclaration */ ||
             node.kind === 231 /* ImportClause */ && !!node.name ||
             node.kind === 232 /* NamespaceImport */ ||
             node.kind === 234 /* ImportSpecifier */ ||
@@ -6301,7 +6315,7 @@ var ts;
     }
     ts.isWellKnownSymbolSyntactically = isWellKnownSymbolSyntactically;
     function getPropertyNameForPropertyNameNode(name) {
-        if (name.kind === 69 /* Identifier */ || name.kind === 9 /* StringLiteral */ || name.kind === 8 /* NumericLiteral */) {
+        if (name.kind === 69 /* Identifier */ || name.kind === 9 /* StringLiteral */ || name.kind === 8 /* NumericLiteral */ || name.kind === 142 /* Parameter */) {
             return name.text;
         }
         if (name.kind === 140 /* ComputedPropertyName */) {
@@ -7773,7 +7787,7 @@ var ts;
             case 231 /* ImportClause */:
                 return visitNode(cbNode, node.name) ||
                     visitNode(cbNode, node.namedBindings);
-            case 228 /* GlobalModuleExportDeclaration */:
+            case 228 /* NamespaceExportDeclaration */:
                 return visitNode(cbNode, node.name);
             case 232 /* NamespaceImport */:
                 return visitNode(cbNode, node.name);
@@ -12182,7 +12196,7 @@ var ts;
             return nextToken() === 39 /* SlashToken */;
         }
         function parseGlobalModuleExportDeclaration(fullStart, decorators, modifiers) {
-            var exportDeclaration = createNode(228 /* GlobalModuleExportDeclaration */, fullStart);
+            var exportDeclaration = createNode(228 /* NamespaceExportDeclaration */, fullStart);
             exportDeclaration.decorators = decorators;
             exportDeclaration.modifiers = modifiers;
             parseExpected(116 /* AsKeyword */);
@@ -15018,10 +15032,10 @@ var ts;
                 case 145 /* PropertyDeclaration */:
                 case 144 /* PropertySignature */:
                 case 266 /* JSDocRecordMember */:
-                    return bindPropertyOrMethodOrAccessor(node, 4 /* Property */ | (node.questionToken ? 536870912 /* Optional */ : 0 /* None */), 107455 /* PropertyExcludes */);
+                    return bindPropertyOrMethodOrAccessor(node, 4 /* Property */ | (node.questionToken ? 536870912 /* Optional */ : 0 /* None */), 0 /* PropertyExcludes */);
                 case 253 /* PropertyAssignment */:
                 case 254 /* ShorthandPropertyAssignment */:
-                    return bindPropertyOrMethodOrAccessor(node, 4 /* Property */, 107455 /* PropertyExcludes */);
+                    return bindPropertyOrMethodOrAccessor(node, 4 /* Property */, 0 /* PropertyExcludes */);
                 case 255 /* EnumMember */:
                     return bindPropertyOrMethodOrAccessor(node, 8 /* EnumMember */, 107455 /* EnumMemberExcludes */);
                 case 247 /* JsxSpreadAttribute */:
@@ -15037,7 +15051,7 @@ var ts;
                     // as other properties in the object literal.  So we use SymbolFlags.PropertyExcludes
                     // so that it will conflict with any other object literal members with the same
                     // name.
-                    return bindPropertyOrMethodOrAccessor(node, 8192 /* Method */ | (node.questionToken ? 536870912 /* Optional */ : 0 /* None */), ts.isObjectLiteralMethod(node) ? 107455 /* PropertyExcludes */ : 99263 /* MethodExcludes */);
+                    return bindPropertyOrMethodOrAccessor(node, 8192 /* Method */ | (node.questionToken ? 536870912 /* Optional */ : 0 /* None */), ts.isObjectLiteralMethod(node) ? 0 /* PropertyExcludes */ : 99263 /* MethodExcludes */);
                 case 220 /* FunctionDeclaration */:
                     return bindFunctionDeclaration(node);
                 case 148 /* Constructor */:
@@ -15081,8 +15095,8 @@ var ts;
                 case 234 /* ImportSpecifier */:
                 case 238 /* ExportSpecifier */:
                     return declareSymbolAndAddToSymbolTable(node, 8388608 /* Alias */, 8388608 /* AliasExcludes */);
-                case 228 /* GlobalModuleExportDeclaration */:
-                    return bindGlobalModuleExportDeclaration(node);
+                case 228 /* NamespaceExportDeclaration */:
+                    return bindNamespaceExportDeclaration(node);
                 case 231 /* ImportClause */:
                     return bindImportClause(node);
                 case 236 /* ExportDeclaration */:
@@ -15120,14 +15134,14 @@ var ts;
             }
             else if (boundExpression.kind === 69 /* Identifier */ && node.kind === 235 /* ExportAssignment */) {
                 // An export default clause with an identifier exports all meanings of that identifier
-                declareSymbol(container.symbol.exports, container.symbol, node, 8388608 /* Alias */, 107455 /* PropertyExcludes */ | 8388608 /* AliasExcludes */);
+                declareSymbol(container.symbol.exports, container.symbol, node, 8388608 /* Alias */, 0 /* PropertyExcludes */ | 8388608 /* AliasExcludes */);
             }
             else {
                 // An export default clause with an expression exports a value
-                declareSymbol(container.symbol.exports, container.symbol, node, 4 /* Property */, 107455 /* PropertyExcludes */ | 8388608 /* AliasExcludes */);
+                declareSymbol(container.symbol.exports, container.symbol, node, 4 /* Property */, 0 /* PropertyExcludes */ | 8388608 /* AliasExcludes */);
             }
         }
-        function bindGlobalModuleExportDeclaration(node) {
+        function bindNamespaceExportDeclaration(node) {
             if (node.modifiers && node.modifiers.length) {
                 file.bindDiagnostics.push(ts.createDiagnosticForNode(node, ts.Diagnostics.Modifiers_cannot_appear_here));
             }
@@ -15186,7 +15200,7 @@ var ts;
             if (container.kind === 179 /* FunctionExpression */ || container.kind === 220 /* FunctionDeclaration */) {
                 container.symbol.members = container.symbol.members || {};
                 // It's acceptable for multiple 'this' assignments of the same identifier to occur
-                declareSymbol(container.symbol.members, container.symbol, node, 4 /* Property */, 107455 /* PropertyExcludes */ & ~4 /* Property */);
+                declareSymbol(container.symbol.members, container.symbol, node, 4 /* Property */, 0 /* PropertyExcludes */ & ~4 /* Property */);
             }
         }
         function bindPrototypePropertyAssignment(node) {
@@ -15209,7 +15223,7 @@ var ts;
                 funcSymbol.members = {};
             }
             // Declare the method/property
-            declareSymbol(funcSymbol.members, funcSymbol, leftSideOfAssignment, 4 /* Property */, 107455 /* PropertyExcludes */);
+            declareSymbol(funcSymbol.members, funcSymbol, leftSideOfAssignment, 4 /* Property */, 0 /* PropertyExcludes */);
         }
         function bindCallExpression(node) {
             // We're only inspecting call expressions to detect CommonJS modules, so we can skip
@@ -15310,7 +15324,7 @@ var ts;
             // containing class.
             if (ts.isParameterPropertyDeclaration(node)) {
                 var classDeclaration = node.parent.parent;
-                declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, 4 /* Property */, 107455 /* PropertyExcludes */);
+                declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, 4 /* Property */, 0 /* PropertyExcludes */);
             }
         }
         function bindFunctionDeclaration(node) {
@@ -15696,7 +15710,7 @@ var ts;
             if (flags & 1 /* FunctionScopedVariable */)
                 result |= 107454 /* FunctionScopedVariableExcludes */;
             if (flags & 4 /* Property */)
-                result |= 107455 /* PropertyExcludes */;
+                result |= 0 /* PropertyExcludes */;
             if (flags & 8 /* EnumMember */)
                 result |= 107455 /* EnumMemberExcludes */;
             if (flags & 16 /* Function */)
@@ -15982,6 +15996,7 @@ var ts;
             var propertyWithInvalidInitializer;
             var errorLocation = location;
             var grandparent;
+            var isInExternalModule = false;
             loop: while (location) {
                 // Locals of a source file are not in scope (because they get merged into the global symbol table)
                 if (location.locals && !isGlobalSourceFile(location)) {
@@ -16024,6 +16039,7 @@ var ts;
                     case 256 /* SourceFile */:
                         if (!ts.isExternalOrCommonJsModule(location))
                             break;
+                        isInExternalModule = true;
                     case 225 /* ModuleDeclaration */:
                         var moduleExports = getSymbolOfNode(location).exports;
                         if (location.kind === 256 /* SourceFile */ || ts.isAmbientModule(location)) {
@@ -16207,6 +16223,13 @@ var ts;
                         checkResolvedBlockScopedVariable(exportOrLocalSymbol, errorLocation);
                     }
                 }
+                // If we're in an external module, we can't reference symbols created from UMD export declarations
+                if (result && isInExternalModule) {
+                    var decls = result.declarations;
+                    if (decls && decls.length === 1 && decls[0].kind === 228 /* NamespaceExportDeclaration */) {
+                        error(errorLocation, ts.Diagnostics.Identifier_0_must_be_imported_from_a_module, name);
+                    }
+                }
             }
             return result;
         }
@@ -16409,7 +16432,7 @@ var ts;
                     return getTargetOfExportSpecifier(node);
                 case 235 /* ExportAssignment */:
                     return getTargetOfExportAssignment(node);
-                case 228 /* GlobalModuleExportDeclaration */:
+                case 228 /* NamespaceExportDeclaration */:
                     return getTargetOfGlobalModuleExportDeclaration(node);
             }
         }
@@ -17883,7 +17906,7 @@ var ts;
         // assigned by contextual typing.
         function getTypeForBindingElementParent(node) {
             var symbol = getSymbolOfNode(node);
-            return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node);
+            return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node, /*includeOptionality*/ false);
         }
         function getTextOfPropertyName(name) {
             switch (name.kind) {
@@ -18009,7 +18032,7 @@ var ts;
             return strictNullChecks && optional ? addNullableKind(type, 32 /* Undefined */) : type;
         }
         // Return the inferred type for a variable, parameter, or property declaration
-        function getTypeForVariableLikeDeclaration(declaration) {
+        function getTypeForVariableLikeDeclaration(declaration, includeOptionality) {
             if (declaration.flags & 134217728 /* JavaScriptFile */) {
                 // If this is a variable in a JavaScript file, then use the JSDoc type (if it has
                 // one as its type), otherwise fallback to the below standard TS codepaths to
@@ -18035,7 +18058,7 @@ var ts;
             }
             // Use type from type annotation if one is present
             if (declaration.type) {
-                return addOptionality(getTypeFromTypeNode(declaration.type), /*optional*/ !!declaration.questionToken);
+                return addOptionality(getTypeFromTypeNode(declaration.type), /*optional*/ declaration.questionToken && includeOptionality);
             }
             if (declaration.kind === 142 /* Parameter */) {
                 var func = declaration.parent;
@@ -18056,12 +18079,12 @@ var ts;
                     ? getContextuallyTypedThisType(func)
                     : getContextuallyTypedParameterType(declaration);
                 if (type) {
-                    return addOptionality(type, /*optional*/ !!declaration.questionToken);
+                    return addOptionality(type, /*optional*/ declaration.questionToken && includeOptionality);
                 }
             }
             // Use the type of the initializer expression if one is present
             if (declaration.initializer) {
-                return addOptionality(checkExpressionCached(declaration.initializer), /*optional*/ !!declaration.questionToken);
+                return addOptionality(checkExpressionCached(declaration.initializer), /*optional*/ declaration.questionToken && includeOptionality);
             }
             // If it is a short-hand property assignment, use the type of the identifier
             if (declaration.kind === 254 /* ShorthandPropertyAssignment */) {
@@ -18155,7 +18178,7 @@ var ts;
         // binding pattern [x, s = ""]. Because the contextual type is a tuple type, the resulting type of [1, "one"] is the
         // tuple type [number, string]. Thus, the type inferred for 'x' is number and the type inferred for 's' is string.
         function getWidenedTypeForVariableLikeDeclaration(declaration, reportErrors) {
-            var type = getTypeForVariableLikeDeclaration(declaration);
+            var type = getTypeForVariableLikeDeclaration(declaration, /*includeOptionality*/ true);
             if (type) {
                 if (reportErrors) {
                     reportErrorsFromWidening(declaration, type);
@@ -20719,7 +20742,7 @@ var ts;
                     return isIdenticalTo(source, target);
                 }
                 if (!(target.flags & 134217728 /* Never */)) {
-                    if (target.flags & 1 /* Any */)
+                    if (target.flags & 1 /* Any */ || source.flags & 134217728 /* Never */)
                         return -1 /* True */;
                     if (source.flags & 32 /* Undefined */) {
                         if (!strictNullChecks || target.flags & (32 /* Undefined */ | 16 /* Void */) || source === emptyArrayElementType)
@@ -20739,7 +20762,7 @@ var ts;
                     if (source.flags & 256 /* StringLiteral */ && target === stringType)
                         return -1 /* True */;
                     if (relation === assignableRelation || relation === comparableRelation) {
-                        if (source.flags & (1 /* Any */ | 134217728 /* Never */))
+                        if (source.flags & 1 /* Any */)
                             return -1 /* True */;
                         if (source === numberType && target.flags & 128 /* Enum */)
                             return -1 /* True */;
@@ -21634,41 +21657,52 @@ var ts;
                 getSignaturesOfType(type, 0 /* Call */).length === 0 &&
                 getSignaturesOfType(type, 1 /* Construct */).length === 0;
         }
+        function createTransientSymbol(source, type) {
+            var symbol = createSymbol(source.flags | 67108864 /* Transient */, source.name);
+            symbol.declarations = source.declarations;
+            symbol.parent = source.parent;
+            symbol.type = type;
+            symbol.target = source;
+            if (source.valueDeclaration) {
+                symbol.valueDeclaration = source.valueDeclaration;
+            }
+            return symbol;
+        }
+        function transformTypeOfMembers(type, f) {
+            var members = {};
+            for (var _i = 0, _a = getPropertiesOfObjectType(type); _i < _a.length; _i++) {
+                var property = _a[_i];
+                var original = getTypeOfSymbol(property);
+                var updated = f(original);
+                members[property.name] = updated === original ? property : createTransientSymbol(property, updated);
+            }
+            ;
+            return members;
+        }
+        /**
+         * If the the provided object literal is subject to the excess properties check,
+         * create a new that is exempt. Recursively mark object literal members as exempt.
+         * Leave signatures alone since they are not subject to the check.
+         */
         function getRegularTypeOfObjectLiteral(type) {
-            if (type.flags & 1048576 /* FreshObjectLiteral */) {
-                var regularType = type.regularType;
-                if (!regularType) {
-                    regularType = createType(type.flags & ~1048576 /* FreshObjectLiteral */);
-                    regularType.symbol = type.symbol;
-                    regularType.members = type.members;
-                    regularType.properties = type.properties;
-                    regularType.callSignatures = type.callSignatures;
-                    regularType.constructSignatures = type.constructSignatures;
-                    regularType.stringIndexInfo = type.stringIndexInfo;
-                    regularType.numberIndexInfo = type.numberIndexInfo;
-                    type.regularType = regularType;
-                }
+            if (!(type.flags & 1048576 /* FreshObjectLiteral */)) {
+                return type;
+            }
+            var regularType = type.regularType;
+            if (regularType) {
                 return regularType;
             }
-            return type;
+            var resolved = type;
+            var members = transformTypeOfMembers(type, getRegularTypeOfObjectLiteral);
+            var regularNew = createAnonymousType(resolved.symbol, members, resolved.callSignatures, resolved.constructSignatures, resolved.stringIndexInfo, resolved.numberIndexInfo);
+            regularNew.flags = resolved.flags & ~1048576 /* FreshObjectLiteral */;
+            type.regularType = regularNew;
+            return regularNew;
         }
         function getWidenedTypeOfObjectLiteral(type) {
-            var properties = getPropertiesOfObjectType(type);
-            var members = {};
-            ts.forEach(properties, function (p) {
-                var propType = getTypeOfSymbol(p);
-                var widenedType = getWidenedType(propType);
-                if (propType !== widenedType) {
-                    var symbol = createSymbol(p.flags | 67108864 /* Transient */, p.name);
-                    symbol.declarations = p.declarations;
-                    symbol.parent = p.parent;
-                    symbol.type = widenedType;
-                    symbol.target = p;
-                    if (p.valueDeclaration)
-                        symbol.valueDeclaration = p.valueDeclaration;
-                    p = symbol;
-                }
-                members[p.name] = p;
+            var members = transformTypeOfMembers(type, function (prop) {
+                var widened = getWidenedType(prop);
+                return prop === widened ? prop : widened;
             });
             var stringIndexInfo = getIndexInfoOfType(type, 0 /* String */);
             var numberIndexInfo = getIndexInfoOfType(type, 1 /* Number */);
@@ -23224,7 +23258,7 @@ var ts;
             }
             return nodeCheckFlag === 512 /* SuperStatic */
                 ? getBaseConstructorTypeOfClass(classType)
-                : baseClassType;
+                : getTypeWithThisArgument(baseClassType, classType.thisType);
             function isLegalUsageOfSuperExpression(container) {
                 if (!container) {
                     return false;
@@ -25936,7 +25970,7 @@ var ts;
                 var types = void 0;
                 var funcIsGenerator = !!func.asteriskToken;
                 if (funcIsGenerator) {
-                    types = checkAndAggregateYieldOperandTypes(func.body, contextualMapper);
+                    types = checkAndAggregateYieldOperandTypes(func, contextualMapper);
                     if (types.length === 0) {
                         var iterableIteratorAny = createIterableIteratorType(anyType);
                         if (compilerOptions.noImplicitAny) {
@@ -25946,8 +25980,7 @@ var ts;
                     }
                 }
                 else {
-                    var hasImplicitReturn = !!(func.flags & 32768 /* HasImplicitReturn */);
-                    types = checkAndAggregateReturnExpressionTypes(func.body, contextualMapper, isAsync, hasImplicitReturn);
+                    types = checkAndAggregateReturnExpressionTypes(func, contextualMapper);
                     if (!types) {
                         return neverType;
                     }
@@ -26001,9 +26034,9 @@ var ts;
                 return widenedType;
             }
         }
-        function checkAndAggregateYieldOperandTypes(body, contextualMapper) {
+        function checkAndAggregateYieldOperandTypes(func, contextualMapper) {
             var aggregatedTypes = [];
-            ts.forEachYieldExpression(body, function (yieldExpression) {
+            ts.forEachYieldExpression(func.body, function (yieldExpression) {
                 var expr = yieldExpression.expression;
                 if (expr) {
                     var type = checkExpressionCached(expr, contextualMapper);
@@ -26018,10 +26051,12 @@ var ts;
             });
             return aggregatedTypes;
         }
-        function checkAndAggregateReturnExpressionTypes(body, contextualMapper, isAsync, hasImplicitReturn) {
+        function checkAndAggregateReturnExpressionTypes(func, contextualMapper) {
+            var isAsync = ts.isAsyncFunctionLike(func);
             var aggregatedTypes = [];
-            var hasOmittedExpressions = false;
-            ts.forEachReturnStatement(body, function (returnStatement) {
+            var hasReturnWithNoExpression = !!(func.flags & 32768 /* HasImplicitReturn */);
+            var hasReturnOfTypeNever = false;
+            ts.forEachReturnStatement(func.body, function (returnStatement) {
                 var expr = returnStatement.expression;
                 if (expr) {
                     var type = checkExpressionCached(expr, contextualMapper);
@@ -26030,20 +26065,24 @@ var ts;
                         // Promise/A+ compatible implementation will always assimilate any foreign promise, so the
                         // return type of the body should be unwrapped to its awaited type, which should be wrapped in
                         // the native Promise<T> type by the caller.
-                        type = checkAwaitedType(type, body.parent, ts.Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
+                        type = checkAwaitedType(type, func, ts.Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
                     }
-                    if (type !== neverType && !ts.contains(aggregatedTypes, type)) {
+                    if (type === neverType) {
+                        hasReturnOfTypeNever = true;
+                    }
+                    else if (!ts.contains(aggregatedTypes, type)) {
                         aggregatedTypes.push(type);
                     }
                 }
                 else {
-                    hasOmittedExpressions = true;
+                    hasReturnWithNoExpression = true;
                 }
             });
-            if (aggregatedTypes.length === 0 && !hasOmittedExpressions && !hasImplicitReturn) {
+            if (aggregatedTypes.length === 0 && !hasReturnWithNoExpression && (hasReturnOfTypeNever ||
+                func.kind === 179 /* FunctionExpression */ || func.kind === 180 /* ArrowFunction */)) {
                 return undefined;
             }
-            if (strictNullChecks && aggregatedTypes.length && (hasOmittedExpressions || hasImplicitReturn)) {
+            if (strictNullChecks && aggregatedTypes.length && hasReturnWithNoExpression) {
                 if (!ts.contains(aggregatedTypes, undefinedType)) {
                     aggregatedTypes.push(undefinedType);
                 }
@@ -26215,8 +26254,14 @@ var ts;
                 if (symbol.flags & 4 /* Property */ &&
                     (expr.kind === 172 /* PropertyAccessExpression */ || expr.kind === 173 /* ElementAccessExpression */) &&
                     expr.expression.kind === 97 /* ThisKeyword */) {
+                    // Look for if this is the constructor for the class that `symbol` is a property of.
                     var func = ts.getContainingFunction(expr);
-                    return !(func && func.kind === 148 /* Constructor */ && func.parent === symbol.valueDeclaration.parent);
+                    if (!(func && func.kind === 148 /* Constructor */))
+                        return true;
+                    // If func.parent is a class and symbol is a (readonly) property of that class, or
+                    // if func is a constructor and symbol is a (readonly) parameter property declared in it,
+                    // then symbol is writeable here.
+                    return !(func.parent === symbol.valueDeclaration.parent || func === symbol.valueDeclaration.parent);
                 }
                 return true;
             }
@@ -27148,6 +27193,79 @@ var ts;
                 }
             }
         }
+        function checkClassForDuplicateDeclarations(node) {
+            var getter = 1, setter = 2, property = getter | setter;
+            var instanceNames = {};
+            var staticNames = {};
+            for (var _i = 0, _a = node.members; _i < _a.length; _i++) {
+                var member = _a[_i];
+                if (member.kind === 148 /* Constructor */) {
+                    for (var _b = 0, _c = member.parameters; _b < _c.length; _b++) {
+                        var param = _c[_b];
+                        if (ts.isParameterPropertyDeclaration(param)) {
+                            addName(instanceNames, param.name, param.name.text, property);
+                        }
+                    }
+                }
+                else {
+                    var static = ts.forEach(member.modifiers, function (m) { return m.kind === 113 /* StaticKeyword */; });
+                    var names = static ? staticNames : instanceNames;
+                    var memberName = member.name && ts.getPropertyNameForPropertyNameNode(member.name);
+                    if (memberName) {
+                        switch (member.kind) {
+                            case 149 /* GetAccessor */:
+                                addName(names, member.name, memberName, getter);
+                                break;
+                            case 150 /* SetAccessor */:
+                                addName(names, member.name, memberName, setter);
+                                break;
+                            case 145 /* PropertyDeclaration */:
+                                addName(names, member.name, memberName, property);
+                                break;
+                        }
+                    }
+                }
+            }
+            function addName(names, location, name, meaning) {
+                if (ts.hasProperty(names, name)) {
+                    var prev = names[name];
+                    if (prev & meaning) {
+                        error(location, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(location));
+                    }
+                    else {
+                        names[name] = prev | meaning;
+                    }
+                }
+                else {
+                    names[name] = meaning;
+                }
+            }
+        }
+        function checkObjectTypeForDuplicateDeclarations(node) {
+            var names = {};
+            for (var _i = 0, _a = node.members; _i < _a.length; _i++) {
+                var member = _a[_i];
+                if (member.kind == 144 /* PropertySignature */) {
+                    var memberName = void 0;
+                    switch (member.name.kind) {
+                        case 9 /* StringLiteral */:
+                        case 8 /* NumericLiteral */:
+                        case 69 /* Identifier */:
+                            memberName = member.name.text;
+                            break;
+                        default:
+                            continue;
+                    }
+                    if (ts.hasProperty(names, memberName)) {
+                        error(member.symbol.valueDeclaration.name, ts.Diagnostics.Duplicate_identifier_0, memberName);
+                        error(member.name, ts.Diagnostics.Duplicate_identifier_0, memberName);
+                    }
+                    else {
+                        names[memberName] = true;
+                    }
+                }
+            }
+        }
         function checkTypeForDuplicateIndexSignatures(node) {
             if (node.kind === 222 /* InterfaceDeclaration */) {
                 var nodeSymbol = getSymbolOfNode(node);
@@ -27399,6 +27517,7 @@ var ts;
                 var type = getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node);
                 checkIndexConstraints(type);
                 checkTypeForDuplicateIndexSignatures(node);
+                checkObjectTypeForDuplicateDeclarations(node);
             }
         }
         function checkArrayType(node) {
@@ -28444,6 +28563,10 @@ var ts;
                 if (node.initializer) {
                     checkTypeAssignableTo(checkExpressionCached(node.initializer), declarationType, node, /*headMessage*/ undefined);
                 }
+                if (!areDeclarationFlagsIdentical(node, symbol.valueDeclaration)) {
+                    error(symbol.valueDeclaration.name, ts.Diagnostics.All_declarations_of_0_must_have_identical_modifiers, ts.declarationNameToString(node.name));
+                    error(node.name, ts.Diagnostics.All_declarations_of_0_must_have_identical_modifiers, ts.declarationNameToString(node.name));
+                }
             }
             if (node.kind !== 145 /* PropertyDeclaration */ && node.kind !== 144 /* PropertySignature */) {
                 // We know we don't have a binding pattern or computed name here
@@ -28457,6 +28580,18 @@ var ts;
                 checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name);
             }
         }
+        function areDeclarationFlagsIdentical(left, right) {
+            if (ts.hasQuestionToken(left) !== ts.hasQuestionToken(right)) {
+                return false;
+            }
+            var interestingFlags = 8 /* Private */ |
+                16 /* Protected */ |
+                256 /* Async */ |
+                128 /* Abstract */ |
+                64 /* Readonly */ |
+                32 /* Static */;
+            return (left.flags & interestingFlags) === (right.flags & interestingFlags);
+        }
         function checkVariableDeclaration(node) {
             checkGrammarVariableDeclaration(node);
             return checkVariableLikeDeclaration(node);
@@ -29150,6 +29285,7 @@ var ts;
             var typeWithThis = getTypeWithThisArgument(type);
             var staticType = getTypeOfSymbol(symbol);
             checkTypeParameterListsIdentical(node, symbol);
+            checkClassForDuplicateDeclarations(node);
             var baseTypeNode = ts.getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
                 var baseTypes = getBaseTypes(type);
@@ -29398,6 +29534,7 @@ var ts;
                         checkIndexConstraints(type);
                     }
                 }
+                checkObjectTypeForDuplicateDeclarations(node);
             }
             ts.forEach(ts.getInterfaceBaseTypeNodes(node), function (heritageElement) {
                 if (!ts.isSupportedExpressionWithTypeArguments(heritageElement)) {
@@ -30241,14 +30378,11 @@ var ts;
         function checkSourceFileWorker(node) {
             var links = getNodeLinks(node);
             if (!(links.flags & 1 /* TypeChecked */)) {
-                // Check whether the file has declared it is the default lib,
-                // and whether the user has specifically chosen to avoid checking it.
-                if (compilerOptions.skipDefaultLibCheck) {
-                    // If the user specified '--noLib' and a file has a '/// <reference no-default-lib="true"/>',
-                    // then we should treat that file as a default lib.
-                    if (node.hasNoDefaultLib) {
-                        return;
-                    }
+                // If skipLibCheck is enabled, skip type checking if file is a declaration file.
+                // If skipDefaultLibCheck is enabled, skip type checking if file contains a
+                // '/// <reference no-default-lib="true"/>' directive.
+                if (compilerOptions.skipLibCheck && node.isDeclarationFile || compilerOptions.skipDefaultLibCheck && node.hasNoDefaultLib) {
+                    return;
                 }
                 // Grammar checking
                 checkGrammarSourceFile(node);
@@ -30665,7 +30799,7 @@ var ts;
                 return symbol && getTypeOfSymbol(symbol);
             }
             if (ts.isBindingPattern(node)) {
-                return getTypeForVariableLikeDeclaration(node.parent);
+                return getTypeForVariableLikeDeclaration(node.parent, /*includeOptionality*/ true);
             }
             if (isInRightSideOfImportOrExportAssignment(node)) {
                 var symbol = getSymbolAtLocation(node);
@@ -31204,7 +31338,7 @@ var ts;
                 if (file.moduleAugmentations.length) {
                     (augmentations || (augmentations = [])).push(file.moduleAugmentations);
                 }
-                if (file.wasReferenced && file.symbol && file.symbol.globalExports) {
+                if (file.symbol && file.symbol.globalExports) {
                     mergeSymbolTable(globals, file.symbol.globalExports);
                 }
             });
@@ -31787,7 +31921,6 @@ var ts;
                     name_20.kind === 140 /* ComputedPropertyName */) {
                     // If the name is not a ComputedPropertyName, the grammar checking will skip it
                     checkGrammarComputedPropertyName(name_20);
-                    return "continue";
                 }
                 if (prop.kind === 254 /* ShorthandPropertyAssignment */ && !inDestructuring && prop.objectAssignmentInitializer) {
                     // having objectAssignmentInitializer is only valid in ObjectAssignmentPattern
@@ -31829,17 +31962,21 @@ var ts;
                 else {
                     ts.Debug.fail("Unexpected syntax kind:" + prop.kind);
                 }
-                if (!ts.hasProperty(seen, name_20.text)) {
-                    seen[name_20.text] = currentKind;
+                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_20);
+                if (effectiveName === undefined) {
+                    return "continue";
+                }
+                if (!ts.hasProperty(seen, effectiveName)) {
+                    seen[effectiveName] = currentKind;
                 }
                 else {
-                    var existingKind = seen[name_20.text];
+                    var existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
-                        return "continue";
+                        grammarErrorOnNode(name_20, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_20));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
-                            seen[name_20.text] = currentKind | existingKind;
+                            seen[effectiveName] = currentKind | existingKind;
                         }
                         else {
                             return { value: grammarErrorOnNode(name_20, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name) };
@@ -41638,8 +41775,8 @@ var ts;
             skipTsx: true,
             traceEnabled: traceEnabled
         };
-        // use typesRoot and fallback to directory that contains tsconfig if typesRoot is not set
-        var rootDir = options.typesRoot || (options.configFilePath ? ts.getDirectoryPath(options.configFilePath) : undefined);
+        // use typesRoot and fallback to directory that contains tsconfig or current directory if typesRoot is not set
+        var rootDir = options.typesRoot || (options.configFilePath ? ts.getDirectoryPath(options.configFilePath) : (host.getCurrentDirectory && host.getCurrentDirectory()));
         if (traceEnabled) {
             if (containingFile === undefined) {
                 if (rootDir === undefined) {
@@ -42229,12 +42366,25 @@ var ts;
                 }
             }
         }
+        function getDefaultTypeDirectiveNames(rootPath) {
+            var localTypes = ts.combinePaths(rootPath, "types");
+            var npmTypes = ts.combinePaths(rootPath, "node_modules/@types");
+            var result = [];
+            if (ts.sys.directoryExists(localTypes)) {
+                result = result.concat(ts.sys.getDirectories(localTypes));
+            }
+            if (ts.sys.directoryExists(npmTypes)) {
+                result = result.concat(ts.sys.getDirectories(npmTypes));
+            }
+            return result;
+        }
         function getDefaultLibLocation() {
             return ts.getDirectoryPath(ts.normalizePath(ts.sys.getExecutingFilePath()));
         }
         var newLine = ts.getNewLineCharacter(options);
         var realpath = ts.sys.realpath && (function (path) { return ts.sys.realpath(path); });
         return {
+            getDefaultTypeDirectiveNames: getDefaultTypeDirectiveNames,
             getSourceFile: getSourceFile,
             getDefaultLibLocation: getDefaultLibLocation,
             getDefaultLibFileName: function (options) { return ts.combinePaths(getDefaultLibLocation(), ts.getDefaultLibFileName(options)); },
@@ -42302,6 +42452,21 @@ var ts;
         }
         return resolutions;
     }
+    function getDefaultTypeDirectiveNames(options, rootFiles, host) {
+        // Use explicit type list from tsconfig.json
+        if (options.types) {
+            return options.types;
+        }
+        // or load all types from the automatic type import fields
+        if (host && host.getDefaultTypeDirectiveNames) {
+            var commonRoot = computeCommonSourceDirectoryOfFilenames(rootFiles, host.getCurrentDirectory(), function (f) { return host.getCanonicalFileName(f); });
+            if (commonRoot) {
+                return host.getDefaultTypeDirectiveNames(commonRoot);
+            }
+        }
+        return undefined;
+    }
+    ts.getDefaultTypeDirectiveNames = getDefaultTypeDirectiveNames;
     function createProgram(rootNames, options, host, oldProgram) {
         var program;
         var files = [];
@@ -42340,14 +42505,15 @@ var ts;
         // used to track cases when two file names differ only in casing
         var filesByNameIgnoreCase = host.useCaseSensitiveFileNames() ? ts.createFileMap(function (fileName) { return fileName.toLowerCase(); }) : undefined;
         if (!tryReuseStructureFromOldProgram()) {
+            ts.forEach(rootNames, function (name) { return processRootFile(name, /*isDefaultLib*/ false); });
             // load type declarations specified via 'types' argument
-            if (options.types && options.types.length) {
-                var resolutions = resolveTypeReferenceDirectiveNamesWorker(options.types, /*containingFile*/ undefined);
-                for (var i = 0; i < options.types.length; i++) {
-                    processTypeReferenceDirective(options.types[i], resolutions[i]);
+            var typeReferences = getDefaultTypeDirectiveNames(options, rootNames, host);
+            if (typeReferences) {
+                var resolutions = resolveTypeReferenceDirectiveNamesWorker(typeReferences, /*containingFile*/ undefined);
+                for (var i = 0; i < typeReferences.length; i++) {
+                    processTypeReferenceDirective(typeReferences[i], resolutions[i]);
                 }
             }
-            ts.forEach(rootNames, function (name) { return processRootFile(name, /*isDefaultLib*/ false); });
             // Do not process the default library if:
             //  - The '--noLib' flag is used.
             //  - A 'no-default-lib' reference comment is encountered in
@@ -42999,9 +43165,6 @@ var ts;
                 if (file_1 && options.forceConsistentCasingInFileNames && ts.getNormalizedAbsolutePath(file_1.fileName, currentDirectory) !== ts.getNormalizedAbsolutePath(fileName, currentDirectory)) {
                     reportFileNamesDifferOnlyInCasingError(fileName, file_1.fileName, refFile, refPos, refEnd);
                 }
-                if (file_1) {
-                    file_1.wasReferenced = file_1.wasReferenced || isReference;
-                }
                 return file_1;
             }
             // We haven't looked for this file, do so now and cache result
@@ -43015,7 +43178,6 @@ var ts;
             });
             filesByName.set(path, file);
             if (file) {
-                file.wasReferenced = file.wasReferenced || isReference;
                 file.path = path;
                 if (host.useCaseSensitiveFileNames()) {
                     // for case-sensitive file systems check if we've already seen some file with similar filename ignoring case
@@ -43129,19 +43291,7 @@ var ts;
                         !options.noResolve &&
                         i < file.imports.length;
                     if (shouldAddFile) {
-                        var importedFile = findSourceFile(resolution.resolvedFileName, ts.toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName), /*isDefaultLib*/ false, /*isReference*/ false, file, ts.skipTrivia(file.text, file.imports[i].pos), file.imports[i].end);
-                        if (importedFile && resolution.isExternalLibraryImport) {
-                            // Since currently irrespective of allowJs, we only look for supportedTypeScript extension external module files,
-                            // this check is ok. Otherwise this would be never true for javascript file
-                            if (!ts.isExternalModule(importedFile) && importedFile.statements.length) {
-                                var start_5 = ts.getTokenPosOfNode(file.imports[i], file);
-                                fileProcessingDiagnostics.add(ts.createFileDiagnostic(file, start_5, file.imports[i].end - start_5, 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 (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));
-                            }
-                        }
+                        findSourceFile(resolution.resolvedFileName, ts.toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName), /*isDefaultLib*/ false, /*isReference*/ false, file, ts.skipTrivia(file.text, file.imports[i].pos), file.imports[i].end);
                     }
                 }
             }
@@ -43227,7 +43377,7 @@ var ts;
                         }
                     }
                     else {
-                        programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Substututions_for_pattern_0_should_be_an_array, key));
+                        programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Substitutions_for_pattern_0_should_be_an_array, key));
                     }
                 }
             }
@@ -43278,15 +43428,21 @@ var ts;
             else if (firstExternalModuleSourceFile && languageVersion < 2 /* ES6 */ && options.module === ts.ModuleKind.None) {
                 // We cannot use createDiagnosticFromNode because nodes do not have parents yet
                 var span = ts.getErrorSpanForNode(firstExternalModuleSourceFile, firstExternalModuleSourceFile.externalModuleIndicator);
-                programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file));
+                programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_use_imports_exports_or_module_augmentations_when_module_is_none));
             }
             // Cannot specify module gen target of es6 when below es6
             if (options.module === ts.ModuleKind.ES6 && languageVersion < 2 /* ES6 */) {
                 programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Cannot_compile_modules_into_es2015_when_targeting_ES5_or_lower));
             }
             // Cannot specify module gen that isn't amd or system with --out
-            if (outFile && options.module && !(options.module === ts.ModuleKind.AMD || options.module === ts.ModuleKind.System)) {
-                programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Only_amd_and_system_modules_are_supported_alongside_0, options.out ? "out" : "outFile"));
+            if (outFile) {
+                if (options.module && !(options.module === ts.ModuleKind.AMD || options.module === ts.ModuleKind.System)) {
+                    programDiagnostics.add(ts.createCompilerDiagnostic(ts.Diagnostics.Only_amd_and_system_modules_are_supported_alongside_0, options.out ? "out" : "outFile"));
+                }
+                else if (options.module === undefined && firstExternalModuleSourceFile) {
+                    var span = ts.getErrorSpanForNode(firstExternalModuleSourceFile, firstExternalModuleSourceFile.externalModuleIndicator);
+                    programDiagnostics.add(ts.createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, ts.Diagnostics.Cannot_compile_modules_using_option_0_unless_the_module_flag_is_amd_or_system, options.out ? "out" : "outFile"));
+                }
             }
             // there has to be common source directory if user specified --outdir || --sourceRoot
             // if user specified --mapRoot, there needs to be common source directory if there would be multiple files being emitted
@@ -43384,6 +43540,11 @@ var ts;
             type: "boolean",
             description: ts.Diagnostics.Print_this_message
         },
+        {
+            name: "help",
+            shortName: "?",
+            type: "boolean"
+        },
         {
             name: "init",
             type: "boolean",
@@ -43486,6 +43647,11 @@ var ts;
             name: "skipDefaultLibCheck",
             type: "boolean"
         },
+        {
+            name: "skipLibCheck",
+            type: "boolean",
+            description: ts.Diagnostics.Skip_type_checking_of_declaration_files
+        },
         {
             name: "out",
             type: "string",
@@ -44315,7 +44481,7 @@ var ts;
 (function (ts) {
     var NavigateTo;
     (function (NavigateTo) {
-        function getNavigateToItems(program, cancellationToken, searchValue, maxResultCount) {
+        function getNavigateToItems(program, checker, cancellationToken, searchValue, maxResultCount) {
             var patternMatcher = ts.createPatternMatcher(searchValue);
             var rawItems = [];
             // This means "compare in a case insensitive manner."
@@ -44354,6 +44520,18 @@ var ts;
                     }
                 }
             });
+            // Remove imports when the imported declaration is already in the list and has the same name.
+            rawItems = ts.filter(rawItems, function (item) {
+                var decl = item.declaration;
+                if (decl.kind === 231 /* ImportClause */ || decl.kind === 234 /* ImportSpecifier */ || decl.kind === 229 /* ImportEqualsDeclaration */) {
+                    var importer = checker.getSymbolAtLocation(decl.name);
+                    var imported = checker.getAliasedSymbol(importer);
+                    return importer.name !== imported.name;
+                }
+                else {
+                    return true;
+                }
+            });
             rawItems.sort(compareNavigateToItems);
             if (maxResultCount !== undefined) {
                 rawItems = rawItems.slice(0, maxResultCount);
@@ -44752,8 +44930,12 @@ var ts;
                         return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.memberSetAccessorElement);
                     case 153 /* IndexSignature */:
                         return createItem(node, "[]", ts.ScriptElementKind.indexSignatureElement);
+                    case 224 /* EnumDeclaration */:
+                        return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.enumElement);
                     case 255 /* EnumMember */:
                         return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.memberVariableElement);
+                    case 222 /* InterfaceDeclaration */:
+                        return createItem(node, getTextOfNode(node.name), ts.ScriptElementKind.interfaceElement);
                     case 151 /* CallSignature */:
                         return createItem(node, "()", ts.ScriptElementKind.callSignatureElement);
                     case 152 /* ConstructSignature */:
@@ -45714,7 +45896,7 @@ var ts;
         // To do this, the method will back parse the expression starting at the position required. it will try to parse the current expression as a generic type expression, if it did succeed it 
         // will return the generic identifier that started the expression (e.g. "foo" in "foo<any, |"). It is then up to the caller to ensure that this is a valid generic expression through 
         // looking up the type. The method will also keep track of the parameter index inside the expression.
-        //public static isInPartiallyWrittenTypeArgumentList(syntaxTree: TypeScript.SyntaxTree, position: number): any {
+        // public static isInPartiallyWrittenTypeArgumentList(syntaxTree: TypeScript.SyntaxTree, position: number): any {
         //    let token = Syntax.findTokenOnLeft(syntaxTree.sourceUnit(), position, /*includeSkippedTokens*/ true);
         //    if (token && TypeScript.Syntax.hasAncestorOfKind(token, TypeScript.SyntaxKind.TypeParameterList)) {
         //        // We are in the wrong generic list. bail out
@@ -45810,8 +45992,8 @@ var ts;
         //        token = previousToken(token, /*includeSkippedTokens*/ true);
         //    }
         //    return null;
-        //}
-        //private static moveBackUpTillMatchingTokenKind(token: TypeScript.ISyntaxToken, tokenKind: TypeScript.SyntaxKind, matchingTokenKind: TypeScript.SyntaxKind): TypeScript.ISyntaxToken {
+        // }
+        // private static moveBackUpTillMatchingTokenKind(token: TypeScript.ISyntaxToken, tokenKind: TypeScript.SyntaxKind, matchingTokenKind: TypeScript.SyntaxKind): TypeScript.ISyntaxToken {
         //    if (!token || token.kind() !== tokenKind) {
         //        throw TypeScript.Errors.invalidOperation();
         //    }
@@ -45840,7 +46022,7 @@ var ts;
         //    }
         //    // Did not find matching token
         //    return null;
-        //}
+        // }
         var emptyArray = [];
         var ArgumentListKind;
         (function (ArgumentListKind) {
@@ -46601,7 +46783,7 @@ var ts;
         }
         /// finds last node that is considered as candidate for search (isCandidate(node) === true) starting from 'exclusiveStartPosition'
         function findRightmostChildNodeWithTokens(children, exclusiveStartPosition) {
-            for (var i = exclusiveStartPosition - 1; i >= 0; --i) {
+            for (var i = exclusiveStartPosition - 1; i >= 0; i--) {
                 if (nodeHasTokens(children[i])) {
                     return children[i];
                 }
@@ -47337,12 +47519,11 @@ var ts;
                 if (!isStarted) {
                     scanner.scan();
                 }
-                var t;
                 var pos = scanner.getStartPos();
                 // Read leading trivia and token
                 while (pos < endPos) {
-                    var t_1 = scanner.getToken();
-                    if (!ts.isTrivia(t_1)) {
+                    var t = scanner.getToken();
+                    if (!ts.isTrivia(t)) {
                         break;
                     }
                     // consume leading trivia
@@ -47350,7 +47531,7 @@ var ts;
                     var item = {
                         pos: pos,
                         end: scanner.getStartPos(),
-                        kind: t_1
+                        kind: t
                     };
                     pos = scanner.getStartPos();
                     if (!leadingTrivia) {
@@ -47690,6 +47871,7 @@ var ts;
     })(formatting = ts.formatting || (ts.formatting = {}));
 })(ts || (ts = {}));
 ///<reference path='references.ts' />
+/* tslint:disable:no-null-keyword */
 /* @internal */
 var ts;
 (function (ts) {
@@ -47951,7 +48133,7 @@ var ts;
                 this.SpaceAfterKeywordInControl = new formatting.Rule(formatting.RuleDescriptor.create2(formatting.Shared.TokenRange.Keywords, 17 /* OpenParenToken */), formatting.RuleOperation.create2(new formatting.RuleOperationContext(Rules.IsControlDeclContext), 2 /* Space */));
                 this.NoSpaceAfterKeywordInControl = new formatting.Rule(formatting.RuleDescriptor.create2(formatting.Shared.TokenRange.Keywords, 17 /* OpenParenToken */), formatting.RuleOperation.create2(new formatting.RuleOperationContext(Rules.IsControlDeclContext), 8 /* Delete */));
                 // Open Brace braces after function
-                //TypeScript: Function can have return types, which can be made of tons of different token kinds
+                // TypeScript: Function can have return types, which can be made of tons of different token kinds
                 this.NewLineBeforeOpenBraceInFunction = new formatting.Rule(formatting.RuleDescriptor.create2(this.FunctionOpenBraceLeftTokenRange, 15 /* OpenBraceToken */), formatting.RuleOperation.create2(new formatting.RuleOperationContext(Rules.IsFunctionDeclContext, Rules.IsBeforeMultilineBlockContext), 4 /* NewLine */), 1 /* CanDeleteNewLines */);
                 // Open Brace braces after TypeScript module/class/interface
                 this.NewLineBeforeOpenBraceInTypeScriptDeclWithBlock = new formatting.Rule(formatting.RuleDescriptor.create2(this.TypeScriptOpenBraceLeftTokenRange, 15 /* OpenBraceToken */), formatting.RuleOperation.create2(new formatting.RuleOperationContext(Rules.IsTypeScriptDeclWithBlockContext, Rules.IsBeforeMultilineBlockContext), 4 /* NewLine */), 1 /* CanDeleteNewLines */);
@@ -48092,17 +48274,17 @@ var ts;
                     case 220 /* FunctionDeclaration */:
                     case 147 /* MethodDeclaration */:
                     case 146 /* MethodSignature */:
-                    //case SyntaxKind.MemberFunctionDeclaration:
+                    // case SyntaxKind.MemberFunctionDeclaration:
                     case 149 /* GetAccessor */:
                     case 150 /* SetAccessor */:
-                    ///case SyntaxKind.MethodSignature:
+                    // case SyntaxKind.MethodSignature:
                     case 151 /* CallSignature */:
                     case 179 /* FunctionExpression */:
                     case 148 /* Constructor */:
                     case 180 /* ArrowFunction */:
-                    //case SyntaxKind.ConstructorDeclaration:
-                    //case SyntaxKind.SimpleArrowFunctionExpression:
-                    //case SyntaxKind.ParenthesizedArrowFunctionExpression:
+                    // case SyntaxKind.ConstructorDeclaration:
+                    // case SyntaxKind.SimpleArrowFunctionExpression:
+                    // case SyntaxKind.ParenthesizedArrowFunctionExpression:
                     case 222 /* InterfaceDeclaration */:
                         return true;
                 }
@@ -48254,6 +48436,7 @@ var ts;
     })(formatting = ts.formatting || (ts.formatting = {}));
 })(ts || (ts = {}));
 ///<reference path='references.ts' />
+/* tslint:disable:no-null-keyword */
 /* @internal */
 var ts;
 (function (ts) {
@@ -48271,9 +48454,9 @@ var ts;
             };
             RulesMap.prototype.Initialize = function (rules) {
                 this.mapRowLength = 138 /* LastToken */ + 1;
-                this.map = new Array(this.mapRowLength * this.mapRowLength); //new Array<RulesBucket>(this.mapRowLength * this.mapRowLength);
+                this.map = new Array(this.mapRowLength * this.mapRowLength); // new Array<RulesBucket>(this.mapRowLength * this.mapRowLength);
                 // This array is used only during construction of the rulesbucket in the map
-                var rulesBucketConstructionStateList = new Array(this.map.length); //new Array<RulesBucketConstructionState>(this.map.length);
+                var rulesBucketConstructionStateList = new Array(this.map.length); // new Array<RulesBucketConstructionState>(this.map.length);
                 this.FillRules(rules, rulesBucketConstructionStateList);
                 return this.map;
             };
@@ -48285,7 +48468,7 @@ var ts;
             };
             RulesMap.prototype.GetRuleBucketIndex = function (row, column) {
                 var rulesBucketIndex = (row * this.mapRowLength) + column;
-                //Debug.Assert(rulesBucketIndex < this.map.Length, "Trying to access an index outside the array.");
+                // Debug.Assert(rulesBucketIndex < this.map.Length, "Trying to access an index outside the array.");
                 return rulesBucketIndex;
             };
             RulesMap.prototype.FillRule = function (rule, rulesBucketConstructionStateList) {
@@ -48537,6 +48720,7 @@ var ts;
 ///<reference path='rulesMap.ts' />
 ///<reference path='tokenRange.ts' /> 
 /// <reference path="references.ts"/>
+/* tslint:disable:no-null-keyword */
 /* @internal */
 var ts;
 (function (ts) {
@@ -49058,7 +49242,7 @@ var ts;
                 // if there are any tokens that logically belong to node and interleave child nodes
                 // such tokens will be consumed in processChildNode for for the child that follows them
                 ts.forEachChild(node, function (child) {
-                    processChildNode(child, /*inheritedIndentation*/ -1 /* Unknown */, node, nodeDynamicIndentation, nodeStartLine, undecoratedNodeStartLine, /*isListElement*/ false);
+                    processChildNode(child, /*inheritedIndentation*/ -1 /* Unknown */, node, nodeDynamicIndentation, nodeStartLine, undecoratedNodeStartLine, /*isListItem*/ false);
                 }, function (nodes) {
                     processChildNodes(nodes, node, nodeStartLine, nodeDynamicIndentation);
                 });
@@ -49149,7 +49333,7 @@ var ts;
                     var inheritedIndentation = -1 /* Unknown */;
                     for (var i = 0; i < nodes.length; i++) {
                         var child = nodes[i];
-                        inheritedIndentation = processChildNode(child, inheritedIndentation, node, listDynamicIndentation, startLine, startLine, /*isListElement*/ true, /*isFirstListItem*/ i === 0);
+                        inheritedIndentation = processChildNode(child, inheritedIndentation, node, listDynamicIndentation, startLine, startLine, /*isListItem*/ true, /*isFirstListItem*/ i === 0);
                     }
                     if (listEndToken !== 0 /* Unknown */) {
                         if (formattingScanner.isOnToken()) {
@@ -49279,7 +49463,7 @@ var ts;
                         // Handle the case where the next line is moved to be the end of this line.
                         // In this case we don't indent the next line in the next pass.
                         if (currentParent.getStart(sourceFile) === currentItem.pos) {
-                            dynamicIndentation.recomputeIndentation(/*lineAdded*/ false);
+                            dynamicIndentation.recomputeIndentation(/*lineAddedByFormatting*/ false);
                         }
                     }
                     else if (rule.Operation.Action & 4 /* NewLine */ && currentStartLine === previousStartLine) {
@@ -49288,7 +49472,7 @@ var ts;
                         // In this case we indent token2 in the next pass but we set
                         // sameLineIndent flag to notify the indenter that the indentation is within the line.
                         if (currentParent.getStart(sourceFile) === currentItem.pos) {
-                            dynamicIndentation.recomputeIndentation(/*lineAdded*/ true);
+                            dynamicIndentation.recomputeIndentation(/*lineAddedByFormatting*/ true);
                         }
                     }
                     // We need to trim trailing whitespace between the tokens if they were on different lines, and no rule was applied to put them on the same line
@@ -49336,7 +49520,7 @@ var ts;
                 else {
                     parts = [];
                     var startPos = commentRange.pos;
-                    for (var line = startLine; line < endLine; ++line) {
+                    for (var line = startLine; line < endLine; line++) {
                         var endOfLine = ts.getEndLinePosition(line, sourceFile);
                         parts.push({ pos: startPos, end: endOfLine });
                         startPos = ts.getStartPositionOfLine(line + 1, sourceFile);
@@ -49355,7 +49539,7 @@ var ts;
                 }
                 // shift all parts on the delta size
                 var delta = indentation - nonWhitespaceColumnInFirstPart.column;
-                for (var i = startIndex, len = parts.length; i < len; ++i, ++startLine) {
+                for (var i = startIndex, len = parts.length; i < len; i++, startLine++) {
                     var startLinePos_1 = ts.getStartPositionOfLine(startLine, sourceFile);
                     var nonWhitespaceCharacterAndColumn = i === 0
                         ? nonWhitespaceColumnInFirstPart
@@ -49371,7 +49555,7 @@ var ts;
                 }
             }
             function trimTrailingWhitespacesForLines(line1, line2, range) {
-                for (var line = line1; line < line2; ++line) {
+                for (var line = line1; line < line2; line++) {
                     var lineStartPosition = ts.getStartPositionOfLine(line, sourceFile);
                     var lineEndPosition = ts.getEndLinePosition(line, sourceFile);
                     // do not trim whitespaces in comments or template expression
@@ -49422,7 +49606,6 @@ var ts;
                 }
             }
             function applyRuleEdits(rule, previousRange, previousStartLine, currentRange, currentStartLine) {
-                var between;
                 switch (rule.Operation.Action) {
                     case 1 /* Ignore */:
                         // no action required
@@ -49459,14 +49642,6 @@ var ts;
                 }
             }
         }
-        function isSomeBlock(kind) {
-            switch (kind) {
-                case 199 /* Block */:
-                case 226 /* ModuleBlock */:
-                    return true;
-            }
-            return false;
-        }
         function getOpenTokenForList(node, list) {
             switch (node.kind) {
                 case 148 /* Constructor */:
@@ -49525,7 +49700,7 @@ var ts;
                     internedTabsIndentation = [];
                 }
                 if (internedTabsIndentation[tabs] === undefined) {
-                    internedTabsIndentation[tabs] = tabString = repeat('\t', tabs);
+                    internedTabsIndentation[tabs] = tabString = repeat("\t", tabs);
                 }
                 else {
                     tabString = internedTabsIndentation[tabs];
@@ -49550,7 +49725,7 @@ var ts;
             }
             function repeat(value, count) {
                 var s = "";
-                for (var i = 0; i < count; ++i) {
+                for (var i = 0; i < count; i++) {
                     s += value;
                 }
                 return s;
@@ -49866,7 +50041,7 @@ var ts;
                 // walk toward the start of the list starting from current node and check if the line is the same for all items.
                 // if end line for item [i - 1] differs from the start line for item [i] - find column of the first non-whitespace character on the line of item [i]
                 var lineAndCharacter = getStartLineAndCharacterForNode(node, sourceFile);
-                for (var i = index - 1; i >= 0; --i) {
+                for (var i = index - 1; i >= 0; i--) {
                     if (list[i].kind === 24 /* CommaToken */) {
                         continue;
                     }
@@ -49893,7 +50068,7 @@ var ts;
             function findFirstNonWhitespaceCharacterAndColumn(startPos, endPos, sourceFile, options) {
                 var character = 0;
                 var column = 0;
-                for (var pos = startPos; pos < endPos; ++pos) {
+                for (var pos = startPos; pos < endPos; pos++) {
                     var ch = sourceFile.text.charCodeAt(pos);
                     if (!ts.isWhiteSpace(ch)) {
                         break;
@@ -49987,7 +50162,7 @@ var ts;
             Function returns true when the parent node should indent the given child by an explicit rule
             */
             function shouldIndentChildNode(parent, child) {
-                return nodeContentIsAlwaysIndented(parent.kind) || nodeWillIndentChild(parent, child, false);
+                return nodeContentIsAlwaysIndented(parent.kind) || nodeWillIndentChild(parent, child, /*indentByDefault*/ false);
             }
             SmartIndenter.shouldIndentChildNode = shouldIndentChildNode;
         })(SmartIndenter = formatting.SmartIndenter || (formatting.SmartIndenter = {}));
@@ -50809,49 +50984,55 @@ var ts;
     (function (ScriptElementKind) {
         ScriptElementKind.unknown = "";
         ScriptElementKind.warning = "warning";
-        // predefined type (void) or keyword (class)
+        /** predefined type (void) or keyword (class) */
         ScriptElementKind.keyword = "keyword";
-        // top level script node
+        /** top level script node */
         ScriptElementKind.scriptElement = "script";
-        // module foo {}
+        /** module foo {} */
         ScriptElementKind.moduleElement = "module";
-        // class X {}
+        /** class X {} */
         ScriptElementKind.classElement = "class";
-        // var x = class X {}
+        /** var x = class X {} */
         ScriptElementKind.localClassElement = "local class";
-        // interface Y {}
+        /** interface Y {} */
         ScriptElementKind.interfaceElement = "interface";
-        // type T = ...
+        /** type T = ... */
         ScriptElementKind.typeElement = "type";
-        // enum E
+        /** enum E */
         ScriptElementKind.enumElement = "enum";
-        // Inside module and script only
-        // const v = ..
+        /**
+         * Inside module and script only
+         * const v = ..
+         */
         ScriptElementKind.variableElement = "var";
-        // Inside function
+        /** Inside function */
         ScriptElementKind.localVariableElement = "local var";
-        // Inside module and script only
-        // function f() { }
+        /**
+         * Inside module and script only
+         * function f() { }
+         */
         ScriptElementKind.functionElement = "function";
-        // Inside function
+        /** Inside function */
         ScriptElementKind.localFunctionElement = "local function";
-        // class X { [public|private]* foo() {} }
+        /** class X { [public|private]* foo() {} } */
         ScriptElementKind.memberFunctionElement = "method";
-        // class X { [public|private]* [get|set] foo:number; }
+        /** class X { [public|private]* [get|set] foo:number; } */
         ScriptElementKind.memberGetAccessorElement = "getter";
         ScriptElementKind.memberSetAccessorElement = "setter";
-        // class X { [public|private]* foo:number; }
-        // interface Y { foo:number; }
+        /**
+         * class X { [public|private]* foo:number; }
+         * interface Y { foo:number; }
+         */
         ScriptElementKind.memberVariableElement = "property";
-        // class X { constructor() { } }
+        /** class X { constructor() { } } */
         ScriptElementKind.constructorImplementationElement = "constructor";
-        // interface Y { ():number; }
+        /** interface Y { ():number; } */
         ScriptElementKind.callSignatureElement = "call";
-        // interface Y { []:number; }
+        /** interface Y { []:number; } */
         ScriptElementKind.indexSignatureElement = "index";
-        // interface Y { new():Y; }
+        /** interface Y { new():Y; } */
         ScriptElementKind.constructSignatureElement = "construct";
-        // function foo(*Y*: string)
+        /** function foo(*Y*: string) */
         ScriptElementKind.parameterElement = "parameter";
         ScriptElementKind.typeParameterElement = "type parameter";
         ScriptElementKind.primitiveType = "primitive type";
@@ -52236,9 +52417,9 @@ 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_6 = new Date().getTime();
+                var start_5 = new Date().getTime();
                 contextToken = ts.findPrecedingToken(contextToken.getFullStart(), sourceFile);
-                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_6));
+                log("getCompletionData: Get previous token 2: " + (new Date().getTime() - start_5));
             }
             // Find the node where completion is requested on.
             // Also determine whether we are trying to complete with members of that node
@@ -52518,13 +52699,13 @@ var ts;
                     || contextToken.kind === 166 /* StringLiteralType */
                     || contextToken.kind === 10 /* RegularExpressionLiteral */
                     || ts.isTemplateLiteralKind(contextToken.kind)) {
-                    var start_7 = contextToken.getStart();
+                    var start_6 = 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_7 < position && position < end) {
+                    if (start_6 < position && position < end) {
                         return true;
                     }
                     if (position === end) {
@@ -53759,8 +53940,7 @@ var ts;
         }
         function getDocumentHighlights(fileName, position, filesToSearch) {
             synchronizeHostData();
-            filesToSearch = ts.map(filesToSearch, ts.normalizeSlashes);
-            var sourceFilesToSearch = ts.filter(program.getSourceFiles(), function (f) { return ts.contains(filesToSearch, f.fileName); });
+            var sourceFilesToSearch = ts.map(filesToSearch, function (f) { return program.getSourceFile(f); });
             var sourceFile = getValidSourceFile(fileName);
             var node = ts.getTouchingWord(sourceFile, position);
             if (!node) {
@@ -55150,7 +55330,8 @@ var ts;
         /// NavigateTo
         function getNavigateToItems(searchValue, maxResultCount) {
             synchronizeHostData();
-            return ts.NavigateTo.getNavigateToItems(program, cancellationToken, searchValue, maxResultCount);
+            var checker = getProgram().getTypeChecker();
+            return ts.NavigateTo.getNavigateToItems(program, checker, cancellationToken, searchValue, maxResultCount);
         }
         function getEmitOutput(fileName) {
             synchronizeHostData();
@@ -57559,6 +57740,9 @@ var ts;
         LanguageServiceShimHostAdapter.prototype.getCurrentDirectory = function () {
             return this.shimHost.getCurrentDirectory();
         };
+        LanguageServiceShimHostAdapter.prototype.getDirectories = function (path) {
+            return this.shimHost.getDirectories(path);
+        };
         LanguageServiceShimHostAdapter.prototype.getDefaultLibFileName = function (options) {
             return this.shimHost.getDefaultLibFileName(JSON.stringify(options));
         };