Merge branch 'navbar_class_child_item' into navbar_modules

Jakefile.js

@@ -726,24 +726,40 @@ function runConsoleTests(defaultReporter, defaultSubsets) {
         subsetRegexes = subsets.map(function (sub) { return "^" + sub + ".*$"; });
         subsetRegexes.push("^(?!" + subsets.join("|") + ").*$");
     }
+    var counter = subsetRegexes.length;
+    var errorStatus;
     subsetRegexes.forEach(function (subsetRegex, i) {
         tests = subsetRegex ? ' -g "' + subsetRegex + '"' : '';
         var cmd = "mocha" + (debug ? " --debug-brk" : "") + " -R " + reporter + tests + colors + ' -t ' + testTimeout + ' ' + run;
         console.log(cmd);
-        function finish() {
+        function finish(status) {
+            counter--;
+            // save first error status
+            if (status !== undefined && errorStatus === undefined) {
+                errorStatus = status;
+            }
+
             deleteTemporaryProjectOutput();
-            complete();
+            if (counter !== 0 || errorStatus === undefined) {
+                // run linter when last worker is finished
+                if (lintFlag && counter === 0) {
+                    var lint = jake.Task['lint'];
+                    lint.addListener('complete', function () {
+                        complete();
+                    });
+                    lint.invoke();
+                }
+                complete();
+            }
+            else {
+                fail("Process exited with code " + status);
+            }
         }
         exec(cmd, function () {
-            if (lintFlag && i === 0) {
-                var lint = jake.Task['lint'];
-                lint.addListener('complete', function () {
-                    complete();
-                });
-                lint.invoke();
-            }
             finish();
-        }, finish);
+        }, function(e, status) {
+            finish(status);
+        });
     });
 }
 
@@ -962,24 +978,13 @@ function lintFileAsync(options, path, cb) {
     });
 }
 
-var servicesLintTargets = [
-    "navigateTo.ts",
-    "navigationBar.ts",
-    "outliningElementsCollector.ts",
-    "patternMatcher.ts",
-    "services.ts",
-    "shims.ts",
-    "jsTyping.ts"
-].map(function (s) {
-    return path.join(servicesDirectory, s);
-});
 var lintTargets = compilerSources
     .concat(harnessSources)
     // Other harness sources
     .concat(["instrumenter.ts"].map(function(f) { return path.join(harnessDirectory, f) }))
     .concat(serverCoreSources)
     .concat(tslintRulesFiles)
-    .concat(servicesLintTargets);
+    .concat(servicesSources);
 
 
 desc("Runs tslint on the compiler sources. Optional arguments are: f[iles]=regex");

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.
   */

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.
   */

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.
   */

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);
@@ -18062,7 +18090,7 @@ var ts;
                             inferFromTypes(source, t);
                         }
                     }
-                    if (target.flags & 16384 && typeParameterCount === 1) {
+                    if (typeParameterCount === 1) {
                         inferiority++;
                         inferFromTypes(source, typeParameter);
                         inferiority--;
@@ -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",

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);
@@ -18816,7 +18854,7 @@ var ts;
                             inferFromTypes(source, t);
                         }
                     }
-                    if (target.flags & 16384 && typeParameterCount === 1) {
+                    if (typeParameterCount === 1) {
                         inferiority++;
                         inferFromTypes(source, typeParameter);
                         inferiority--;
@@ -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));
         };

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 {

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);
@@ -18816,7 +18854,7 @@ var ts;
                             inferFromTypes(source, t);
                         }
                     }
-                    if (target.flags & 16384 && typeParameterCount === 1) {
+                    if (typeParameterCount === 1) {
                         inferiority++;
                         inferFromTypes(source, typeParameter);
                         inferiority--;
@@ -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));
         };

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;

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;

scripts/tslint/noIncrementDecrementRule.ts

@@ -28,8 +28,15 @@ class IncrementDecrementWalker extends Lint.RuleWalker {
     }
 
     visitIncrementDecrement(node: ts.UnaryExpression) {
-        if (node.parent && (node.parent.kind === ts.SyntaxKind.ExpressionStatement ||
-                            node.parent.kind === ts.SyntaxKind.ForStatement)) {
+        if (node.parent && (
+            // Can be a statement
+            node.parent.kind === ts.SyntaxKind.ExpressionStatement ||
+            // Can be directly in a for-statement
+            node.parent.kind === ts.SyntaxKind.ForStatement ||
+            // Can be in a comma operator in a for statement (`for (let a = 0, b = 10; a < b; a++, b--)`)
+            node.parent.kind === ts.SyntaxKind.BinaryExpression &&
+            (<ts.BinaryExpression>node.parent).operatorToken.kind === ts.SyntaxKind.CommaToken &&
+            node.parent.parent.kind === ts.SyntaxKind.ForStatement)) {
             return;
         }
         this.addFailure(this.createFailure(node.getStart(), node.getWidth(), Rule.POSTFIX_FAILURE_STRING));

src/compiler/checker.ts

@@ -7158,11 +7158,10 @@ namespace ts {
                             inferFromTypes(source, t);
                         }
                     }
-                    // Next, if target is a union type containing a single naked type parameter, make a
-                    // secondary inference to that type parameter. We don't do this for intersection types
-                    // because in a target type like Foo & T we don't know how which parts of the source type
-                    // should be matched by Foo and which should be inferred to T.
-                    if (target.flags & TypeFlags.Union && typeParameterCount === 1) {
+                    // Next, if target containings a single naked type parameter, make a secondary inference to that type
+                    // parameter. This gives meaningful results for union types in co-variant positions and intersection
+                    // types in contra-variant positions (such as callback parameters).
+                    if (typeParameterCount === 1) {
                         inferiority++;
                         inferFromTypes(source, typeParameter);
                         inferiority--;
@@ -12972,18 +12971,20 @@ namespace ts {
                     const names = static ? staticNames : instanceNames;
 
                     const memberName = member.name && getPropertyNameForPropertyNameNode(member.name);
-                    switch (member.kind) {
-                        case SyntaxKind.GetAccessor:
-                            addName(names, member.name, memberName, getter);
-                            break;
+                    if (memberName) {
+                        switch (member.kind) {
+                            case SyntaxKind.GetAccessor:
+                                addName(names, member.name, memberName, getter);
+                                break;
 
-                        case SyntaxKind.SetAccessor:
-                            addName(names, member.name, memberName, setter);
-                            break;
+                            case SyntaxKind.SetAccessor:
+                                addName(names, member.name, memberName, setter);
+                                break;
 
-                        case SyntaxKind.PropertyDeclaration:
-                            addName(names, member.name, memberName, property);
-                            break;
+                            case SyntaxKind.PropertyDeclaration:
+                                addName(names, member.name, memberName, property);
+                                break;
+                        }
                     }
                 }
             }

src/harness/fourslash.ts

@@ -1096,14 +1096,6 @@ namespace FourSlash {
             }
             addSpanInfoString();
             return resultString;
-
-            function repeatString(count: number, char: string) {
-                let result = "";
-                for (let i = 0; i < count; i++) {
-                    result += char;
-                }
-                return result;
-            }
         }
 
         public getBreakpointStatementLocation(pos: number) {
@@ -2055,7 +2047,7 @@ namespace FourSlash {
 
             for (let i = 0; i < length; i++) {
                 const item = items[i];
-                Harness.IO.log(`name: ${item.text}, kind: ${item.kind}`);
+                Harness.IO.log(`${repeatString(item.indent, " ")}name: ${item.text}, kind: ${item.kind}, childItems: ${item.childItems.map(child => child.text)}`);
             }
         }
 
@@ -2742,6 +2734,14 @@ ${code}
             fileName: fileName
         };
     }
+
+    function repeatString(count: number, char: string) {
+        let result = "";
+        for (let i = 0; i < count; i++) {
+            result += char;
+        }
+        return result;
+    }
 }
 
 namespace FourSlashInterface {

src/services/breakpoints.ts

@@ -15,7 +15,7 @@ namespace ts.BreakpointResolver {
         }
 
         let tokenAtLocation = getTokenAtPosition(sourceFile, position);
-        let lineOfPosition = sourceFile.getLineAndCharacterOfPosition(position).line;
+        const lineOfPosition = sourceFile.getLineAndCharacterOfPosition(position).line;
         if (sourceFile.getLineAndCharacterOfPosition(tokenAtLocation.getStart(sourceFile)).line > lineOfPosition) {
             // Get previous token if the token is returned starts on new line
             // eg: let x =10; |--- cursor is here
@@ -216,7 +216,7 @@ namespace ts.BreakpointResolver {
                         return spanInNodeIfStartsOnSameLine(findPrecedingToken(node.pos, sourceFile));
 
                     case SyntaxKind.CommaToken:
-                        return spanInPreviousNode(node)
+                        return spanInPreviousNode(node);
 
                     case SyntaxKind.OpenBraceToken:
                         return spanInOpenBraceToken(node);
@@ -259,13 +259,13 @@ namespace ts.BreakpointResolver {
                         if (isArrayLiteralOrObjectLiteralDestructuringPattern(node)) {
                             return spanInArrayLiteralOrObjectLiteralDestructuringPattern(<DestructuringPattern>node);
                         }
-                        
+
                         // Set breakpoint on identifier element of destructuring pattern
                         // a or ...c  or d: x from 
                         // [a, b, ...c] or { a, b } or { d: x } from destructuring pattern
                         if ((node.kind === SyntaxKind.Identifier ||
-                            node.kind == SyntaxKind.SpreadElementExpression || 
-                            node.kind === SyntaxKind.PropertyAssignment || 
+                            node.kind == SyntaxKind.SpreadElementExpression ||
+                            node.kind === SyntaxKind.PropertyAssignment ||
                             node.kind === SyntaxKind.ShorthandPropertyAssignment) &&
                             isArrayLiteralOrObjectLiteralDestructuringPattern(node.parent)) {
                             return textSpan(node);
@@ -325,14 +325,14 @@ namespace ts.BreakpointResolver {
                                     break;
                             }
                         }
-                        
+
                         // If this is name of property assignment, set breakpoint in the initializer
                         if (node.parent.kind === SyntaxKind.PropertyAssignment &&
-                            (<PropertyDeclaration>node.parent).name === node && 
+                            (<PropertyDeclaration>node.parent).name === node &&
                             !isArrayLiteralOrObjectLiteralDestructuringPattern(node.parent.parent)) {
                             return spanInNode((<PropertyDeclaration>node.parent).initializer);
                         }
-                        
+
                         // Breakpoint in type assertion goes to its operand
                         if (node.parent.kind === SyntaxKind.TypeAssertionExpression && (<TypeAssertion>node.parent).type === node) {
                             return spanInNextNode((<TypeAssertion>node.parent).type);
@@ -370,7 +370,7 @@ namespace ts.BreakpointResolver {
             }
 
             function textSpanFromVariableDeclaration(variableDeclaration: VariableDeclaration): TextSpan {
-                let declarations = variableDeclaration.parent.declarations;
+                const declarations = variableDeclaration.parent.declarations;
                 if (declarations && declarations[0] === variableDeclaration) {
                     // First declaration - include let keyword
                     return textSpan(findPrecedingToken(variableDeclaration.pos, sourceFile, variableDeclaration.parent), variableDeclaration);
@@ -386,7 +386,7 @@ namespace ts.BreakpointResolver {
                 if (variableDeclaration.parent.parent.kind === SyntaxKind.ForInStatement) {
                     return spanInNode(variableDeclaration.parent.parent);
                 }
-                
+
                 // If this is a destructuring pattern, set breakpoint in binding pattern
                 if (isBindingPattern(variableDeclaration.name)) {
                     return spanInBindingPattern(<BindingPattern>variableDeclaration.name);
@@ -400,7 +400,7 @@ namespace ts.BreakpointResolver {
                     return textSpanFromVariableDeclaration(variableDeclaration);
                 }
 
-                let declarations = variableDeclaration.parent.declarations;
+                const declarations = variableDeclaration.parent.declarations;
                 if (declarations && declarations[0] !== variableDeclaration) {
                     // If we cannot set breakpoint on this declaration, set it on previous one
                     // Because the variable declaration may be binding pattern and 
@@ -425,8 +425,8 @@ namespace ts.BreakpointResolver {
                     return textSpan(parameter);
                 }
                 else {
-                    let functionDeclaration = <FunctionLikeDeclaration>parameter.parent;
-                    let indexOfParameter = indexOf(functionDeclaration.parameters, parameter);
+                    const functionDeclaration = <FunctionLikeDeclaration>parameter.parent;
+                    const indexOfParameter = indexOf(functionDeclaration.parameters, parameter);
                     if (indexOfParameter) {
                         // Not a first parameter, go to previous parameter
                         return spanInParameterDeclaration(functionDeclaration.parameters[indexOfParameter - 1]);
@@ -459,7 +459,7 @@ namespace ts.BreakpointResolver {
             }
 
             function spanInFunctionBlock(block: Block): TextSpan {
-                let nodeForSpanInBlock = block.statements.length ? block.statements[0] : block.getLastToken();
+                const nodeForSpanInBlock = block.statements.length ? block.statements[0] : block.getLastToken();
                 if (canFunctionHaveSpanInWholeDeclaration(<FunctionLikeDeclaration>block.parent)) {
                     return spanInNodeIfStartsOnSameLine(block.parent, nodeForSpanInBlock);
                 }
@@ -493,7 +493,7 @@ namespace ts.BreakpointResolver {
             function spanInInitializerOfForLike(forLikeStatement: ForStatement | ForOfStatement | ForInStatement): TextSpan {
                 if (forLikeStatement.initializer.kind === SyntaxKind.VariableDeclarationList) {
                     // Declaration list - set breakpoint in first declaration
-                    let variableDeclarationList = <VariableDeclarationList>forLikeStatement.initializer;
+                    const variableDeclarationList = <VariableDeclarationList>forLikeStatement.initializer;
                     if (variableDeclarationList.declarations.length > 0) {
                         return spanInNode(variableDeclarationList.declarations[0]);
                     }
@@ -519,7 +519,7 @@ namespace ts.BreakpointResolver {
 
             function spanInBindingPattern(bindingPattern: BindingPattern): TextSpan {
                 // Set breakpoint in first binding element
-                let firstBindingElement = forEach(bindingPattern.elements,
+                const firstBindingElement = forEach(bindingPattern.elements,
                     element => element.kind !== SyntaxKind.OmittedExpression ? element : undefined);
 
                 if (firstBindingElement) {
@@ -616,7 +616,7 @@ namespace ts.BreakpointResolver {
                     default:
                         if (isArrayLiteralOrObjectLiteralDestructuringPattern(node.parent)) {
                             // Breakpoint in last binding element or binding pattern if it contains no elements
-                            let objectLiteral = <ObjectLiteralExpression>node.parent;
+                            const objectLiteral = <ObjectLiteralExpression>node.parent;
                             return textSpan(lastOrUndefined(objectLiteral.properties) || objectLiteral);
                         }
                         return spanInNode(node.parent);
@@ -633,7 +633,7 @@ namespace ts.BreakpointResolver {
                     default:
                         if (isArrayLiteralOrObjectLiteralDestructuringPattern(node.parent)) {
                             // Breakpoint in last binding element or binding pattern if it contains no elements
-                            let arrayLiteral = <ArrayLiteralExpression>node.parent;
+                            const arrayLiteral = <ArrayLiteralExpression>node.parent;
                             return textSpan(lastOrUndefined(arrayLiteral.elements) || arrayLiteral);
                         }
 
@@ -686,7 +686,7 @@ namespace ts.BreakpointResolver {
             function spanInColonToken(node: Node): TextSpan {
                 // Is this : specifying return annotation of the function declaration
                 if (isFunctionLike(node.parent) ||
-                    node.parent.kind === SyntaxKind.PropertyAssignment || 
+                    node.parent.kind === SyntaxKind.PropertyAssignment ||
                     node.parent.kind === SyntaxKind.Parameter) {
                     return spanInPreviousNode(node);
                 }

src/services/formatting/formatting.ts

@@ -26,8 +26,8 @@ namespace ts.formatting {
      * while(true)
      * { let x;
      * }
-     * Normally indentation is applied only to the first token in line so at glance 'var' should not be touched.
-     * However if some format rule adds new line between '}' and 'var' 'var' will become
+     * Normally indentation is applied only to the first token in line so at glance 'let' should not be touched.
+     * However if some format rule adds new line between '}' and 'let' 'let' will become
      * the first token in line so it should be indented
      */
     interface DynamicIndentation {
@@ -64,11 +64,11 @@ namespace ts.formatting {
 
     interface Indentation {
         indentation: number;
-        delta: number
+        delta: number;
     }
 
     export function formatOnEnter(position: number, sourceFile: SourceFile, rulesProvider: RulesProvider, options: FormatCodeOptions): TextChange[] {
-        let line = sourceFile.getLineAndCharacterOfPosition(position).line;
+        const line = sourceFile.getLineAndCharacterOfPosition(position).line;
         if (line === 0) {
             return [];
         }
@@ -81,12 +81,12 @@ namespace ts.formatting {
         while (isWhiteSpace(sourceFile.text.charCodeAt(endOfFormatSpan)) && !isLineBreak(sourceFile.text.charCodeAt(endOfFormatSpan))) {
             endOfFormatSpan--;
         }
-        let span = {
+        const span = {
             // get start position for the previous line
             pos: getStartPositionOfLine(line - 1, sourceFile),
             // end value is exclusive so add 1 to the result
             end: endOfFormatSpan + 1
-        }
+        };
         return formatSpan(span, sourceFile, options, rulesProvider, FormattingRequestKind.FormatOnEnter);
     }
 
@@ -99,7 +99,7 @@ namespace ts.formatting {
     }
 
     export function formatDocument(sourceFile: SourceFile, rulesProvider: RulesProvider, options: FormatCodeOptions): TextChange[] {
-        let span = {
+        const span = {
             pos: 0,
             end: sourceFile.text.length
         };
@@ -108,7 +108,7 @@ namespace ts.formatting {
 
     export function formatSelection(start: number, end: number, sourceFile: SourceFile, rulesProvider: RulesProvider, options: FormatCodeOptions): TextChange[] {
         // format from the beginning of the line
-        let span = {
+        const span = {
             pos: getLineStartPositionForPosition(start, sourceFile),
             end: end
         };
@@ -116,11 +116,11 @@ namespace ts.formatting {
     }
 
     function formatOutermostParent(position: number, expectedLastToken: SyntaxKind, sourceFile: SourceFile, options: FormatCodeOptions, rulesProvider: RulesProvider, requestKind: FormattingRequestKind): TextChange[] {
-        let parent = findOutermostParent(position, expectedLastToken, sourceFile);
+        const parent = findOutermostParent(position, expectedLastToken, sourceFile);
         if (!parent) {
             return [];
         }
-        let span = {
+        const span = {
             pos: getLineStartPositionForPosition(parent.getStart(sourceFile), sourceFile),
             end: parent.end
         };
@@ -128,7 +128,7 @@ namespace ts.formatting {
     }
 
     function findOutermostParent(position: number, expectedTokenKind: SyntaxKind, sourceFile: SourceFile): Node {
-        let precedingToken = findPrecedingToken(position, sourceFile);
+        const precedingToken = findPrecedingToken(position, sourceFile);
 
         // when it is claimed that trigger character was typed at given position
         // we verify that there is a token with a matching kind whose end is equal to position (because the character was just typed).
@@ -168,7 +168,7 @@ namespace ts.formatting {
             case SyntaxKind.InterfaceDeclaration:
                 return rangeContainsRange((<InterfaceDeclaration>parent).members, node);
             case SyntaxKind.ModuleDeclaration:
-                let body = (<ModuleDeclaration>parent).body;
+                const body = (<ModuleDeclaration>parent).body;
                 return body && body.kind === SyntaxKind.Block && rangeContainsRange((<Block>body).statements, node);
             case SyntaxKind.SourceFile:
             case SyntaxKind.Block:
@@ -186,9 +186,9 @@ namespace ts.formatting {
         return find(sourceFile);
 
         function find(n: Node): Node {
-            let candidate = forEachChild(n, c => startEndContainsRange(c.getStart(sourceFile), c.end, range) && c);
+            const candidate = forEachChild(n, c => startEndContainsRange(c.getStart(sourceFile), c.end, range) && c);
             if (candidate) {
-                let result = find(candidate);
+                const result = find(candidate);
                 if (result) {
                     return result;
                 }
@@ -208,7 +208,7 @@ namespace ts.formatting {
         }
 
         // pick only errors that fall in range
-        let sorted = errors
+        const sorted = errors
             .filter(d => rangeOverlapsWithStartEnd(originalRange, d.start, d.start + d.length))
             .sort((e1, e2) => e1.start - e2.start);
 
@@ -227,7 +227,7 @@ namespace ts.formatting {
                     return false;
                 }
 
-                let error = sorted[index];
+                const error = sorted[index];
                 if (r.end <= error.start) {
                     // specified range ends before the error refered by 'index' - no error in range
                     return false;
@@ -253,12 +253,12 @@ namespace ts.formatting {
       * and return its end as start position for the scanner.
       */
     function getScanStartPosition(enclosingNode: Node, originalRange: TextRange, sourceFile: SourceFile): number {
-        let start = enclosingNode.getStart(sourceFile);
+        const start = enclosingNode.getStart(sourceFile);
         if (start === originalRange.pos && enclosingNode.end === originalRange.end) {
             return start;
         }
 
-        let precedingToken = findPrecedingToken(originalRange.pos, sourceFile);
+        const precedingToken = findPrecedingToken(originalRange.pos, sourceFile);
         if (!precedingToken) {
             // no preceding token found - start from the beginning of enclosing node
             return enclosingNode.pos;
@@ -292,7 +292,7 @@ namespace ts.formatting {
         let previousLine = Constants.Unknown;
         let child: Node;
         while (n) {
-            let line = sourceFile.getLineAndCharacterOfPosition(n.getStart(sourceFile)).line;
+            const line = sourceFile.getLineAndCharacterOfPosition(n.getStart(sourceFile)).line;
             if (previousLine !== Constants.Unknown && line !== previousLine) {
                 break;
             }
@@ -314,17 +314,17 @@ namespace ts.formatting {
         rulesProvider: RulesProvider,
         requestKind: FormattingRequestKind): TextChange[] {
 
-        let rangeContainsError = prepareRangeContainsErrorFunction(sourceFile.parseDiagnostics, originalRange);
+        const rangeContainsError = prepareRangeContainsErrorFunction(sourceFile.parseDiagnostics, originalRange);
 
         // formatting context is used by rules provider
-        let formattingContext = new FormattingContext(sourceFile, requestKind);
+        const formattingContext = new FormattingContext(sourceFile, requestKind);
 
         // find the smallest node that fully wraps the range and compute the initial indentation for the node
-        let enclosingNode = findEnclosingNode(originalRange, sourceFile);
+        const enclosingNode = findEnclosingNode(originalRange, sourceFile);
 
-        let formattingScanner = getFormattingScanner(sourceFile, getScanStartPosition(enclosingNode, originalRange, sourceFile), originalRange.end);
+        const formattingScanner = getFormattingScanner(sourceFile, getScanStartPosition(enclosingNode, originalRange, sourceFile), originalRange.end);
 
-        let initialIndentation = SmartIndenter.getIndentationForNode(enclosingNode, originalRange, sourceFile, options);
+        const initialIndentation = SmartIndenter.getIndentationForNode(enclosingNode, originalRange, sourceFile, options);
 
         let previousRangeHasError: boolean;
         let previousRange: TextRangeWithKind;
@@ -334,23 +334,23 @@ namespace ts.formatting {
         let lastIndentedLine: number;
         let indentationOnLastIndentedLine: number;
 
-        let edits: TextChange[] = [];
+        const edits: TextChange[] = [];
 
         formattingScanner.advance();
 
         if (formattingScanner.isOnToken()) {
-            let startLine = sourceFile.getLineAndCharacterOfPosition(enclosingNode.getStart(sourceFile)).line;
+            const startLine = sourceFile.getLineAndCharacterOfPosition(enclosingNode.getStart(sourceFile)).line;
             let undecoratedStartLine = startLine;
             if (enclosingNode.decorators) {
                 undecoratedStartLine = sourceFile.getLineAndCharacterOfPosition(getNonDecoratorTokenPosOfNode(enclosingNode, sourceFile)).line;
             }
 
-            let delta = getOwnOrInheritedDelta(enclosingNode, options, sourceFile);
+            const delta = getOwnOrInheritedDelta(enclosingNode, options, sourceFile);
             processNode(enclosingNode, enclosingNode, startLine, undecoratedStartLine, initialIndentation, delta);
         }
 
         if (!formattingScanner.isOnToken()) {
-            let leadingTrivia = formattingScanner.getCurrentLeadingTrivia();
+            const leadingTrivia = formattingScanner.getCurrentLeadingTrivia();
             if (leadingTrivia) {
                 processTrivia(leadingTrivia, enclosingNode, enclosingNode, undefined);
                 trimTrailingWhitespacesForRemainingRange();
@@ -384,11 +384,11 @@ namespace ts.formatting {
                 }
             }
             else {
-                let startLine = sourceFile.getLineAndCharacterOfPosition(startPos).line;
-                let startLinePosition = getLineStartPositionForPosition(startPos, sourceFile);
-                let column = SmartIndenter.findFirstNonWhitespaceColumn(startLinePosition, startPos, sourceFile, options);
+                const startLine = sourceFile.getLineAndCharacterOfPosition(startPos).line;
+                const startLinePosition = getLineStartPositionForPosition(startPos, sourceFile);
+                const column = SmartIndenter.findFirstNonWhitespaceColumn(startLinePosition, startPos, sourceFile, options);
                 if (startLine !== parentStartLine || startPos === column) {
-                    return column
+                    return column;
                 }
             }
 
@@ -404,7 +404,7 @@ namespace ts.formatting {
             effectiveParentStartLine: number): Indentation {
 
             let indentation = inheritedIndentation;
-            var delta = SmartIndenter.shouldIndentChildNode(node) ? options.IndentSize : 0;
+            let delta = SmartIndenter.shouldIndentChildNode(node) ? options.IndentSize : 0;
 
             if (effectiveParentStartLine === startLine) {
                 // if node is located on the same line with the parent
@@ -427,7 +427,7 @@ namespace ts.formatting {
             return {
                 indentation,
                 delta
-            }
+            };
         }
 
         function getFirstNonDecoratorTokenOfNode(node: Node) {
@@ -511,7 +511,7 @@ namespace ts.formatting {
                         }
                     }
                 }
-            }
+            };
 
             function getEffectiveDelta(delta: number, child: TextRangeWithKind) {
                 // Delta value should be zero when the node explicitly prevents indentation of the child node
@@ -524,7 +524,7 @@ namespace ts.formatting {
                 return;
             }
 
-            let nodeDynamicIndentation = getDynamicIndentation(node, nodeStartLine, indentation, delta);
+            const nodeDynamicIndentation = getDynamicIndentation(node, nodeStartLine, indentation, delta);
 
             // a useful observations when tracking context node
             //        /
@@ -545,7 +545,7 @@ namespace ts.formatting {
             forEachChild(
                 node,
                 child => {
-                    processChildNode(child, /*inheritedIndentation*/ Constants.Unknown, node, nodeDynamicIndentation, nodeStartLine, undecoratedNodeStartLine, /*isListElement*/ false)
+                    processChildNode(child, /*inheritedIndentation*/ Constants.Unknown, node, nodeDynamicIndentation, nodeStartLine, undecoratedNodeStartLine, /*isListItem*/ false);
                 },
                 (nodes: NodeArray<Node>) => {
                     processChildNodes(nodes, node, nodeStartLine, nodeDynamicIndentation);
@@ -553,7 +553,7 @@ namespace ts.formatting {
 
             // proceed any tokens in the node that are located after child nodes
             while (formattingScanner.isOnToken()) {
-                let tokenInfo = formattingScanner.readTokenInfo(node);
+                const tokenInfo = formattingScanner.readTokenInfo(node);
                 if (tokenInfo.token.end > node.end) {
                     break;
                 }
@@ -570,9 +570,9 @@ namespace ts.formatting {
                 isListItem: boolean,
                 isFirstListItem?: boolean): number {
 
-                let childStartPos = child.getStart(sourceFile);
+                const childStartPos = child.getStart(sourceFile);
 
-                let childStartLine = sourceFile.getLineAndCharacterOfPosition(childStartPos).line;
+                const childStartLine = sourceFile.getLineAndCharacterOfPosition(childStartPos).line;
 
                 let undecoratedChildStartLine = childStartLine;
                 if (child.decorators) {
@@ -599,7 +599,7 @@ namespace ts.formatting {
 
                 while (formattingScanner.isOnToken()) {
                     // proceed any parent tokens that are located prior to child.getStart()
-                    let tokenInfo = formattingScanner.readTokenInfo(node);
+                    const tokenInfo = formattingScanner.readTokenInfo(node);
                     if (tokenInfo.token.end > childStartPos) {
                         // stop when formatting scanner advances past the beginning of the child
                         break;
@@ -614,14 +614,14 @@ namespace ts.formatting {
 
                 if (isToken(child)) {
                     // if child node is a token, it does not impact indentation, proceed it using parent indentation scope rules
-                    let tokenInfo = formattingScanner.readTokenInfo(child);
+                    const tokenInfo = formattingScanner.readTokenInfo(child);
                     Debug.assert(tokenInfo.token.end === child.end);
                     consumeTokenAndAdvanceScanner(tokenInfo, node, parentDynamicIndentation, child);
                     return inheritedIndentation;
                 }
 
-                let effectiveParentStartLine = child.kind === SyntaxKind.Decorator ? childStartLine : undecoratedParentStartLine;
-                let childIndentation = computeIndentation(child, childStartLine, childIndentationAmount, node, parentDynamicIndentation, effectiveParentStartLine);
+                const effectiveParentStartLine = child.kind === SyntaxKind.Decorator ? childStartLine : undecoratedParentStartLine;
+                const childIndentation = computeIndentation(child, childStartLine, childIndentationAmount, node, parentDynamicIndentation, effectiveParentStartLine);
 
                 processNode(child, childContextNode, childStartLine, undecoratedChildStartLine, childIndentation.indentation, childIndentation.delta);
 
@@ -639,8 +639,8 @@ namespace ts.formatting {
                 parentStartLine: number,
                 parentDynamicIndentation: DynamicIndentation): void {
 
-                let listStartToken = getOpenTokenForList(parent, nodes);
-                let listEndToken = getCloseTokenForOpenToken(listStartToken);
+                const listStartToken = getOpenTokenForList(parent, nodes);
+                const listEndToken = getCloseTokenForOpenToken(listStartToken);
 
                 let listDynamicIndentation = parentDynamicIndentation;
                 let startLine = parentStartLine;
@@ -648,7 +648,7 @@ namespace ts.formatting {
                 if (listStartToken !== SyntaxKind.Unknown) {
                     // introduce a new indentation scope for lists (including list start and end tokens)
                     while (formattingScanner.isOnToken()) {
-                        let tokenInfo = formattingScanner.readTokenInfo(parent);
+                        const tokenInfo = formattingScanner.readTokenInfo(parent);
                         if (tokenInfo.token.end > nodes.pos) {
                             // stop when formatting scanner moves past the beginning of node list
                             break;
@@ -656,7 +656,7 @@ namespace ts.formatting {
                         else if (tokenInfo.token.kind === listStartToken) {
                             // consume list start token
                             startLine = sourceFile.getLineAndCharacterOfPosition(tokenInfo.token.pos).line;
-                            let indentation =
+                            const indentation =
                                 computeIndentation(tokenInfo.token, startLine, Constants.Unknown, parent, parentDynamicIndentation, parentStartLine);
 
                             listDynamicIndentation = getDynamicIndentation(parent, parentStartLine, indentation.indentation, indentation.delta);
@@ -672,12 +672,12 @@ namespace ts.formatting {
                 let inheritedIndentation = Constants.Unknown;
                 for (let i = 0; i < nodes.length; i++) {
                     const 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 !== SyntaxKind.Unknown) {
                     if (formattingScanner.isOnToken()) {
-                        let tokenInfo = formattingScanner.readTokenInfo(parent);
+                        const tokenInfo = formattingScanner.readTokenInfo(parent);
                         // consume the list end token only if it is still belong to the parent
                         // there might be the case when current token matches end token but does not considered as one
                         // function (x: function) <--
@@ -693,7 +693,7 @@ namespace ts.formatting {
             function consumeTokenAndAdvanceScanner(currentTokenInfo: TokenInfo, parent: Node, dynamicIndentation: DynamicIndentation, container?: Node): void {
                 Debug.assert(rangeContainsRange(parent, currentTokenInfo.token));
 
-                let lastTriviaWasNewLine = formattingScanner.lastTrailingTriviaWasNewLine();
+                const lastTriviaWasNewLine = formattingScanner.lastTrailingTriviaWasNewLine();
                 let indentToken = false;
 
                 if (currentTokenInfo.leadingTrivia) {
@@ -701,13 +701,13 @@ namespace ts.formatting {
                 }
 
                 let lineAdded: boolean;
-                let isTokenInRange = rangeContainsRange(originalRange, currentTokenInfo.token);
+                const isTokenInRange = rangeContainsRange(originalRange, currentTokenInfo.token);
 
-                let tokenStart = sourceFile.getLineAndCharacterOfPosition(currentTokenInfo.token.pos);
+                const tokenStart = sourceFile.getLineAndCharacterOfPosition(currentTokenInfo.token.pos);
                 if (isTokenInRange) {
-                    let rangeHasError = rangeContainsError(currentTokenInfo.token);
+                    const rangeHasError = rangeContainsError(currentTokenInfo.token);
                     // save previousRange since processRange will overwrite this value with current one
-                    let savePreviousRange = previousRange;
+                    const savePreviousRange = previousRange;
                     lineAdded = processRange(currentTokenInfo.token, tokenStart, parent, childContextNode, dynamicIndentation);
                     if (rangeHasError) {
                         // do not indent comments\token if token range overlaps with some error
@@ -730,15 +730,15 @@ namespace ts.formatting {
                 }
 
                 if (indentToken) {
-                    let tokenIndentation = (isTokenInRange && !rangeContainsError(currentTokenInfo.token)) ?
+                    const tokenIndentation = (isTokenInRange && !rangeContainsError(currentTokenInfo.token)) ?
                         dynamicIndentation.getIndentationForToken(tokenStart.line, currentTokenInfo.token.kind, container) :
                         Constants.Unknown;
 
                     let indentNextTokenOrTrivia = true;
                     if (currentTokenInfo.leadingTrivia) {
-                        let commentIndentation = dynamicIndentation.getIndentationForComment(currentTokenInfo.token.kind, tokenIndentation, container);
+                        const commentIndentation = dynamicIndentation.getIndentationForComment(currentTokenInfo.token.kind, tokenIndentation, container);
 
-                        for (let triviaItem of currentTokenInfo.leadingTrivia) {
+                        for (const triviaItem of currentTokenInfo.leadingTrivia) {
                             const triviaInRange = rangeContainsRange(originalRange, triviaItem);
                             switch (triviaItem.kind) {
                                 case SyntaxKind.MultiLineCommentTrivia:
@@ -776,9 +776,9 @@ namespace ts.formatting {
         }
 
         function processTrivia(trivia: TextRangeWithKind[], parent: Node, contextNode: Node, dynamicIndentation: DynamicIndentation): void {
-            for (let triviaItem of trivia) {
+            for (const triviaItem of trivia) {
                 if (isComment(triviaItem.kind) && rangeContainsRange(originalRange, triviaItem)) {
-                    let triviaItemStart = sourceFile.getLineAndCharacterOfPosition(triviaItem.pos);
+                    const triviaItemStart = sourceFile.getLineAndCharacterOfPosition(triviaItem.pos);
                     processRange(triviaItem, triviaItemStart, parent, contextNode, dynamicIndentation);
                 }
             }
@@ -790,17 +790,17 @@ namespace ts.formatting {
             contextNode: Node,
             dynamicIndentation: DynamicIndentation): boolean {
 
-            let rangeHasError = rangeContainsError(range);
+            const rangeHasError = rangeContainsError(range);
             let lineAdded: boolean;
             if (!rangeHasError && !previousRangeHasError) {
                 if (!previousRange) {
                     // trim whitespaces starting from the beginning of the span up to the current line
-                    let originalStart = sourceFile.getLineAndCharacterOfPosition(originalRange.pos);
+                    const originalStart = sourceFile.getLineAndCharacterOfPosition(originalRange.pos);
                     trimTrailingWhitespacesForLines(originalStart.line, rangeStart.line);
                 }
                 else {
                     lineAdded =
-                        processPair(range, rangeStart.line, parent, previousRange, previousRangeStartLine, previousParent, contextNode, dynamicIndentation)
+                        processPair(range, rangeStart.line, parent, previousRange, previousRangeStartLine, previousParent, contextNode, dynamicIndentation);
                 }
             }
 
@@ -823,7 +823,7 @@ namespace ts.formatting {
 
             formattingContext.updateContext(previousItem, previousParent, currentItem, currentParent, contextNode);
 
-            let rule = rulesProvider.getRulesMap().GetRule(formattingContext);
+            const rule = rulesProvider.getRulesMap().GetRule(formattingContext);
 
             let trimTrailingWhitespaces: boolean;
             let lineAdded: boolean;
@@ -835,7 +835,7 @@ namespace ts.formatting {
                     // 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 & RuleAction.NewLine && currentStartLine === previousStartLine) {
@@ -844,7 +844,7 @@ namespace ts.formatting {
                     // 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);
                     }
                 }
 
@@ -864,15 +864,15 @@ namespace ts.formatting {
         }
 
         function insertIndentation(pos: number, indentation: number, lineAdded: boolean): void {
-            let indentationString = getIndentationString(indentation, options);
+            const indentationString = getIndentationString(indentation, options);
             if (lineAdded) {
                 // new line is added before the token by the formatting rules
                 // insert indentation string at the very beginning of the token
                 recordReplace(pos, 0, indentationString);
             }
             else {
-                let tokenStart = sourceFile.getLineAndCharacterOfPosition(pos);
-                let startLinePosition = getStartPositionOfLine(tokenStart.line, sourceFile);
+                const tokenStart = sourceFile.getLineAndCharacterOfPosition(pos);
+                const startLinePosition = getStartPositionOfLine(tokenStart.line, sourceFile);
                 if (indentation !== tokenStart.character || indentationIsDifferent(indentationString, startLinePosition)) {
                     recordReplace(startLinePosition, tokenStart.character, indentationString);
                 }
@@ -886,7 +886,7 @@ namespace ts.formatting {
         function indentMultilineComment(commentRange: TextRange, indentation: number, firstLineIsIndented: boolean) {
             // split comment in lines
             let startLine = sourceFile.getLineAndCharacterOfPosition(commentRange.pos).line;
-            let endLine = sourceFile.getLineAndCharacterOfPosition(commentRange.end).line;
+            const endLine = sourceFile.getLineAndCharacterOfPosition(commentRange.end).line;
             let parts: TextRange[];
             if (startLine === endLine) {
                 if (!firstLineIsIndented) {
@@ -898,8 +898,8 @@ namespace ts.formatting {
             else {
                 parts = [];
                 let startPos = commentRange.pos;
-                for (let line = startLine; line < endLine; ++line) {
-                    let endOfLine = getEndLinePosition(line, sourceFile);
+                for (let line = startLine; line < endLine; line++) {
+                    const endOfLine = getEndLinePosition(line, sourceFile);
                     parts.push({ pos: startPos, end: endOfLine });
                     startPos = getStartPositionOfLine(line + 1, sourceFile);
                 }
@@ -907,9 +907,9 @@ namespace ts.formatting {
                 parts.push({ pos: startPos, end: commentRange.end });
             }
 
-            let startLinePos = getStartPositionOfLine(startLine, sourceFile);
+            const startLinePos = getStartPositionOfLine(startLine, sourceFile);
 
-            let nonWhitespaceColumnInFirstPart =
+            const nonWhitespaceColumnInFirstPart =
                 SmartIndenter.findFirstNonWhitespaceCharacterAndColumn(startLinePos, parts[0].pos, sourceFile, options);
 
             if (indentation === nonWhitespaceColumnInFirstPart.column) {
@@ -923,17 +923,17 @@ namespace ts.formatting {
             }
 
             // shift all parts on the delta size
-            let delta = indentation - nonWhitespaceColumnInFirstPart.column;
-            for (let i = startIndex, len = parts.length; i < len; ++i, ++startLine) {
-                let startLinePos = getStartPositionOfLine(startLine, sourceFile);
-                let nonWhitespaceCharacterAndColumn =
+            const delta = indentation - nonWhitespaceColumnInFirstPart.column;
+            for (let i = startIndex, len = parts.length; i < len; i++, startLine++) {
+                const startLinePos = getStartPositionOfLine(startLine, sourceFile);
+                const nonWhitespaceCharacterAndColumn =
                     i === 0
                         ? nonWhitespaceColumnInFirstPart
                         : SmartIndenter.findFirstNonWhitespaceCharacterAndColumn(parts[i].pos, parts[i].end, sourceFile, options);
 
-                let newIndentation = nonWhitespaceCharacterAndColumn.column + delta;
+                const newIndentation = nonWhitespaceCharacterAndColumn.column + delta;
                 if (newIndentation > 0) {
-                    let indentationString = getIndentationString(newIndentation, options);
+                    const indentationString = getIndentationString(newIndentation, options);
                     recordReplace(startLinePos, nonWhitespaceCharacterAndColumn.character, indentationString);
                 }
                 else {
@@ -943,16 +943,16 @@ namespace ts.formatting {
         }
 
         function trimTrailingWhitespacesForLines(line1: number, line2: number, range?: TextRangeWithKind) {
-            for (let line = line1; line < line2; ++line) {
-                let lineStartPosition = getStartPositionOfLine(line, sourceFile);
-                let lineEndPosition = getEndLinePosition(line, sourceFile);
+            for (let line = line1; line < line2; line++) {
+                const lineStartPosition = getStartPositionOfLine(line, sourceFile);
+                const lineEndPosition = getEndLinePosition(line, sourceFile);
 
                 // do not trim whitespaces in comments or template expression
                 if (range && (isComment(range.kind) || isStringOrRegularExpressionOrTemplateLiteral(range.kind)) && range.pos <= lineEndPosition && range.end > lineEndPosition) {
                     continue;
                 }
 
-                let whitespaceStart = getTrailingWhitespaceStartPosition(lineStartPosition, lineEndPosition);
+                const whitespaceStart = getTrailingWhitespaceStartPosition(lineStartPosition, lineEndPosition);
                 if (whitespaceStart !== -1) {
                     Debug.assert(whitespaceStart === lineStartPosition || !isWhiteSpace(sourceFile.text.charCodeAt(whitespaceStart - 1)));
                     recordDelete(whitespaceStart, lineEndPosition + 1 - whitespaceStart);
@@ -979,16 +979,16 @@ namespace ts.formatting {
          * Trimming will be done for lines after the previous range
          */
         function trimTrailingWhitespacesForRemainingRange() {
-            let startPosition = previousRange ? previousRange.end : originalRange.pos;
+            const startPosition = previousRange ? previousRange.end : originalRange.pos;
 
-            let startLine = sourceFile.getLineAndCharacterOfPosition(startPosition).line;
-            let endLine = sourceFile.getLineAndCharacterOfPosition(originalRange.end).line;
+            const startLine = sourceFile.getLineAndCharacterOfPosition(startPosition).line;
+            const endLine = sourceFile.getLineAndCharacterOfPosition(originalRange.end).line;
 
             trimTrailingWhitespacesForLines(startLine, endLine + 1, previousRange);
         }
 
         function newTextChange(start: number, len: number, newText: string): TextChange {
-            return { span: createTextSpan(start, len), newText }
+            return { span: createTextSpan(start, len), newText };
         }
 
         function recordDelete(start: number, len: number) {
@@ -1009,7 +1009,6 @@ namespace ts.formatting {
             currentRange: TextRangeWithKind,
             currentStartLine: number): void {
 
-            let between: TextRange;
             switch (rule.Operation.Action) {
                 case RuleAction.Ignore:
                     // no action required
@@ -1029,7 +1028,7 @@ namespace ts.formatting {
                     }
 
                     // edit should not be applied only if we have one line feed between elements
-                    let lineDelta = currentStartLine - previousStartLine;
+                    const lineDelta = currentStartLine - previousStartLine;
                     if (lineDelta !== 1) {
                         recordReplace(previousRange.end, currentRange.pos - previousRange.end, options.NewLineCharacter);
                     }
@@ -1040,7 +1039,7 @@ namespace ts.formatting {
                         return;
                     }
 
-                    let posDelta = currentRange.pos - previousRange.end;
+                    const posDelta = currentRange.pos - previousRange.end;
                     if (posDelta !== 1 || sourceFile.text.charCodeAt(previousRange.end) !== CharacterCodes.space) {
                         recordReplace(previousRange.end, currentRange.pos - previousRange.end, " ");
                     }
@@ -1049,15 +1048,6 @@ namespace ts.formatting {
         }
     }
 
-    function isSomeBlock(kind: SyntaxKind): boolean {
-        switch (kind) {
-            case SyntaxKind.Block:
-            case SyntaxKind.ModuleBlock:
-                return true;
-        }
-        return false;
-    }
-
     function getOpenTokenForList(node: Node, list: Node[]) {
         switch (node.kind) {
             case SyntaxKind.Constructor:
@@ -1102,13 +1092,13 @@ namespace ts.formatting {
         return SyntaxKind.Unknown;
     }
 
-    var internedSizes: { tabSize: number; indentSize: number };
-    var internedTabsIndentation: string[];
-    var internedSpacesIndentation: string[];
+    let internedSizes: { tabSize: number; indentSize: number };
+    let internedTabsIndentation: string[];
+    let internedSpacesIndentation: string[];
 
     export function getIndentationString(indentation: number, options: FormatCodeOptions): string {
         // reset interned strings if FormatCodeOptions were changed
-        let resetInternedStrings =
+        const resetInternedStrings =
             !internedSizes || (internedSizes.tabSize !== options.TabSize || internedSizes.indentSize !== options.IndentSize);
 
         if (resetInternedStrings) {
@@ -1117,8 +1107,8 @@ namespace ts.formatting {
         }
 
         if (!options.ConvertTabsToSpaces) {
-            let tabs = Math.floor(indentation / options.TabSize);
-            let spaces = indentation - tabs * options.TabSize;
+            const tabs = Math.floor(indentation / options.TabSize);
+            const spaces = indentation - tabs * options.TabSize;
 
             let tabString: string;
             if (!internedTabsIndentation) {
@@ -1126,7 +1116,7 @@ namespace ts.formatting {
             }
 
             if (internedTabsIndentation[tabs] === undefined) {
-                internedTabsIndentation[tabs] = tabString = repeat('\t', tabs);
+                internedTabsIndentation[tabs] = tabString = repeat("\t", tabs);
             }
             else {
                 tabString = internedTabsIndentation[tabs];
@@ -1136,8 +1126,8 @@ namespace ts.formatting {
         }
         else {
             let spacesString: string;
-            let quotient = Math.floor(indentation / options.IndentSize);
-            let remainder = indentation % options.IndentSize;
+            const quotient = Math.floor(indentation / options.IndentSize);
+            const remainder = indentation % options.IndentSize;
             if (!internedSpacesIndentation) {
                 internedSpacesIndentation = [];
             }
@@ -1155,7 +1145,7 @@ namespace ts.formatting {
 
         function repeat(value: string, count: number): string {
             let s = "";
-            for (let i = 0; i < count; ++i) {
+            for (let i = 0; i < count; i++) {
                 s += value;
             }
 

src/services/formatting/formattingContext.ts

@@ -57,8 +57,8 @@ namespace ts.formatting {
 
         public TokensAreOnSameLine(): boolean {
             if (this.tokensAreOnSameLine === undefined) {
-                let startLine = this.sourceFile.getLineAndCharacterOfPosition(this.currentTokenSpan.pos).line;
-                let endLine = this.sourceFile.getLineAndCharacterOfPosition(this.nextTokenSpan.pos).line;
+                const startLine = this.sourceFile.getLineAndCharacterOfPosition(this.currentTokenSpan.pos).line;
+                const endLine = this.sourceFile.getLineAndCharacterOfPosition(this.nextTokenSpan.pos).line;
                 this.tokensAreOnSameLine = (startLine === endLine);
             }
 
@@ -82,17 +82,17 @@ namespace ts.formatting {
         }
 
         private NodeIsOnOneLine(node: Node): boolean {
-            let startLine = this.sourceFile.getLineAndCharacterOfPosition(node.getStart(this.sourceFile)).line;
-            let endLine = this.sourceFile.getLineAndCharacterOfPosition(node.getEnd()).line;
+            const startLine = this.sourceFile.getLineAndCharacterOfPosition(node.getStart(this.sourceFile)).line;
+            const endLine = this.sourceFile.getLineAndCharacterOfPosition(node.getEnd()).line;
             return startLine === endLine;
         }
 
         private BlockIsOnOneLine(node: Node): boolean {
-            let openBrace = findChildOfKind(node, SyntaxKind.OpenBraceToken, this.sourceFile);
-            let closeBrace = findChildOfKind(node, SyntaxKind.CloseBraceToken, this.sourceFile);
+            const openBrace = findChildOfKind(node, SyntaxKind.OpenBraceToken, this.sourceFile);
+            const closeBrace = findChildOfKind(node, SyntaxKind.CloseBraceToken, this.sourceFile);
             if (openBrace && closeBrace) {
-                let startLine = this.sourceFile.getLineAndCharacterOfPosition(openBrace.getEnd()).line;
-                let endLine = this.sourceFile.getLineAndCharacterOfPosition(closeBrace.getStart(this.sourceFile)).line;
+                const startLine = this.sourceFile.getLineAndCharacterOfPosition(openBrace.getEnd()).line;
+                const endLine = this.sourceFile.getLineAndCharacterOfPosition(closeBrace.getStart(this.sourceFile)).line;
                 return startLine === endLine;
             }
             return false;

src/services/formatting/formattingScanner.ts

@@ -35,7 +35,7 @@ namespace ts.formatting {
         scanner.setText(sourceFile.text);
         scanner.setTextPos(startPos);
 
-        let wasNewLine: boolean = true;
+        let wasNewLine = true;
         let leadingTrivia: TextRangeWithKind[];
         let trailingTrivia: TextRangeWithKind[];
 
@@ -56,13 +56,13 @@ namespace ts.formatting {
                 scanner.setText(undefined);
                 scanner = undefined;
             }
-        }
+        };
 
         function advance(): void {
             Debug.assert(scanner !== undefined);
 
             lastTokenInfo = undefined;
-            let isStarted = scanner.getStartPos() !== startPos;
+            const isStarted = scanner.getStartPos() !== startPos;
 
             if (isStarted) {
                 if (trailingTrivia) {
@@ -81,23 +81,22 @@ namespace ts.formatting {
                 scanner.scan();
             }
 
-            let t: SyntaxKind;
             let pos = scanner.getStartPos();
 
             // Read leading trivia and token
             while (pos < endPos) {
-                let t = scanner.getToken();
+                const t = scanner.getToken();
                 if (!isTrivia(t)) {
                     break;
                 }
 
                 // consume leading trivia
                 scanner.scan();
-                let item = {
+                const item = {
                     pos: pos,
                     end: scanner.getStartPos(),
                     kind: t
-                }
+                };
 
                 pos = scanner.getStartPos();
 
@@ -166,16 +165,16 @@ namespace ts.formatting {
 
             // normally scanner returns the smallest available token
             // check the kind of context node to determine if scanner should have more greedy behavior and consume more text.
-            let expectedScanAction =
+            const expectedScanAction =
                 shouldRescanGreaterThanToken(n)
                 ? ScanAction.RescanGreaterThanToken
-                : shouldRescanSlashToken(n) 
-                    ? ScanAction.RescanSlashToken 
+                : shouldRescanSlashToken(n)
+                    ? ScanAction.RescanSlashToken
                     : shouldRescanTemplateToken(n)
                         ? ScanAction.RescanTemplateToken
                         : shouldRescanJsxIdentifier(n)
-                            ? ScanAction.RescanJsxIdentifier 
-                            : ScanAction.Scan
+                            ? ScanAction.RescanJsxIdentifier
+                            : ScanAction.Scan;
 
             if (lastTokenInfo && expectedScanAction === lastScanAction) {
                 // readTokenInfo was called before with the same expected scan action.
@@ -218,11 +217,11 @@ namespace ts.formatting {
                 lastScanAction = ScanAction.Scan;
             }
 
-            let token: TextRangeWithKind = {
+            const token: TextRangeWithKind = {
                 pos: scanner.getStartPos(),
                 end: scanner.getTextPos(),
                 kind: currentToken
-            }
+            };
 
             // consume trailing trivia
             if (trailingTrivia) {
@@ -233,7 +232,7 @@ namespace ts.formatting {
                 if (!isTrivia(currentToken)) {
                     break;
                 }
-                let trivia = {
+                const trivia = {
                     pos: scanner.getStartPos(),
                     end: scanner.getTextPos(),
                     kind: currentToken
@@ -256,7 +255,7 @@ namespace ts.formatting {
                 leadingTrivia: leadingTrivia,
                 trailingTrivia: trailingTrivia,
                 token: token
-            }
+            };
 
             return fixTokenKind(lastTokenInfo, n);
         }
@@ -264,8 +263,8 @@ namespace ts.formatting {
         function isOnToken(): boolean {
             Debug.assert(scanner !== undefined);
 
-            let current = (lastTokenInfo && lastTokenInfo.token.kind) || scanner.getToken();
-            let startPos = (lastTokenInfo && lastTokenInfo.token.pos) || scanner.getStartPos();
+            const current = (lastTokenInfo && lastTokenInfo.token.kind) || scanner.getToken();
+            const startPos = (lastTokenInfo && lastTokenInfo.token.pos) || scanner.getStartPos();
             return startPos < endPos && current !== SyntaxKind.EndOfFileToken && !isTrivia(current);
         }
 

src/services/formatting/ruleOperation.ts

@@ -3,13 +3,7 @@
 /* @internal */
 namespace ts.formatting {
     export class RuleOperation {
-        public Context: RuleOperationContext;
-        public Action: RuleAction;
-
-        constructor() {
-            this.Context = null;
-            this.Action = null;
-        }
+        constructor(public Context: RuleOperationContext, public Action: RuleAction) {}
 
         public toString(): string {
             return "[context=" + this.Context + "," +
@@ -17,14 +11,11 @@ namespace ts.formatting {
         }
 
         static create1(action: RuleAction) {
-            return RuleOperation.create2(RuleOperationContext.Any, action)
+            return RuleOperation.create2(RuleOperationContext.Any, action);
         }
 
         static create2(context: RuleOperationContext, action: RuleAction) {
-            let result = new RuleOperation();
-            result.Context = context;
-            result.Action = action;
-            return result;
+            return new RuleOperation(context, action);
         }
     }
 }

src/services/formatting/ruleOperationContext.ts

@@ -5,7 +5,7 @@ namespace ts.formatting {
 
     export class RuleOperationContext {
         private customContextChecks: { (context: FormattingContext): boolean; }[];
-        
+
         constructor(...funcs: { (context: FormattingContext): boolean; }[]) {
             this.customContextChecks = funcs;
         }
@@ -22,7 +22,7 @@ namespace ts.formatting {
                 return true;
             }
 
-            for (let check of this.customContextChecks) {
+            for (const check of this.customContextChecks) {
                 if (!check(context)) {
                     return false;
                 }

src/services/formatting/rules.ts

@@ -4,8 +4,8 @@
 namespace ts.formatting {
     export class Rules {
         public getRuleName(rule: Rule) {
-            let o: ts.Map<any> = <any>this;
-            for (let name in o) {
+            const o: ts.Map<any> = <any>this;
+            for (const name in o) {
                 if (o[name] === rule) {
                     return name;
                 }
@@ -166,7 +166,7 @@ namespace ts.formatting {
         public NoSpaceAfterKeywordInControl: Rule;
 
         // 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
         public FunctionOpenBraceLeftTokenRange: Shared.TokenRange;
         public SpaceBeforeOpenBraceInFunction: Rule;
         public NewLineBeforeOpenBraceInFunction: Rule;
@@ -313,7 +313,7 @@ namespace ts.formatting {
             this.SpaceAfterVoidOperator = new Rule(RuleDescriptor.create3(SyntaxKind.VoidKeyword, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsVoidOpContext), RuleAction.Space));
 
             this.NoSpaceBetweenReturnAndSemicolon = new Rule(RuleDescriptor.create1(SyntaxKind.ReturnKeyword, SyntaxKind.SemicolonToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            
+
             // Add a space between statements. All keywords except (do,else,case) has open/close parens after them.
             // So, we have a rule to add a space for [),Any], [do,Any], [else,Any], and [case,Any]
             this.SpaceBetweenStatements = new Rule(RuleDescriptor.create4(Shared.TokenRange.FromTokens([SyntaxKind.CloseParenToken, SyntaxKind.DoKeyword, SyntaxKind.ElseKeyword, SyntaxKind.CaseKeyword]), Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsNotForContext), RuleAction.Space));
@@ -458,7 +458,7 @@ namespace ts.formatting {
             this.NoSpaceAfterKeywordInControl = new Rule(RuleDescriptor.create2(Shared.TokenRange.Keywords, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsControlDeclContext), RuleAction.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 Rule(RuleDescriptor.create2(this.FunctionOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsFunctionDeclContext, Rules.IsBeforeMultilineBlockContext), RuleAction.NewLine), RuleFlags.CanDeleteNewLines);
 
             // Open Brace braces after TypeScript module/class/interface
@@ -616,17 +616,17 @@ namespace ts.formatting {
                 case SyntaxKind.FunctionDeclaration:
                 case SyntaxKind.MethodDeclaration:
                 case SyntaxKind.MethodSignature:
-                //case SyntaxKind.MemberFunctionDeclaration:
+                // case SyntaxKind.MemberFunctionDeclaration:
                 case SyntaxKind.GetAccessor:
                 case SyntaxKind.SetAccessor:
-                ///case SyntaxKind.MethodSignature:
+                // case SyntaxKind.MethodSignature:
                 case SyntaxKind.CallSignature:
                 case SyntaxKind.FunctionExpression:
                 case SyntaxKind.Constructor:
                 case SyntaxKind.ArrowFunction:
-                //case SyntaxKind.ConstructorDeclaration:
-                //case SyntaxKind.SimpleArrowFunctionExpression:
-                //case SyntaxKind.ParenthesizedArrowFunctionExpression:
+                // case SyntaxKind.ConstructorDeclaration:
+                // case SyntaxKind.SimpleArrowFunctionExpression:
+                // case SyntaxKind.ParenthesizedArrowFunctionExpression:
                 case SyntaxKind.InterfaceDeclaration: // This one is not truly a function, but for formatting purposes, it acts just like one
                     return true;
             }
@@ -724,7 +724,7 @@ namespace ts.formatting {
         }
 
         static IsNotBeforeBlockInFunctionDeclarationContext(context: FormattingContext): boolean {
-            return !Rules.IsFunctionDeclContext(context) && !Rules.IsBeforeBlockContext(context)
+            return !Rules.IsFunctionDeclContext(context) && !Rules.IsBeforeBlockContext(context);
         }
 
         static IsEndOfDecoratorContextOnSameLine(context: FormattingContext): boolean {
@@ -755,7 +755,7 @@ namespace ts.formatting {
         }
 
         static IsObjectTypeContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.TypeLiteral;// && context.contextNode.parent.kind !== SyntaxKind.InterfaceDeclaration;
+            return context.contextNode.kind === SyntaxKind.TypeLiteral; // && context.contextNode.parent.kind !== SyntaxKind.InterfaceDeclaration;
         }
 
         static IsTypeArgumentOrParameterOrAssertion(token: TextRangeWithKind, parent: Node): boolean {

src/services/formatting/rulesMap.ts

@@ -12,17 +12,17 @@ namespace ts.formatting {
         }
 
         static create(rules: Rule[]): RulesMap {
-            let result = new RulesMap();
+            const result = new RulesMap();
             result.Initialize(rules);
             return result;
         }
 
         public Initialize(rules: Rule[]) {
             this.mapRowLength = SyntaxKind.LastToken + 1;
-            this.map = <any> new Array(this.mapRowLength * this.mapRowLength);//new Array<RulesBucket>(this.mapRowLength * this.mapRowLength);
+            this.map = <any> 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
-            let rulesBucketConstructionStateList: RulesBucketConstructionState[] = <any> new Array(this.map.length);//new Array<RulesBucketConstructionState>(this.map.length);
+            const rulesBucketConstructionStateList: RulesBucketConstructionState[] = <any>new Array(this.map.length); // new Array<RulesBucketConstructionState>(this.map.length);
 
             this.FillRules(rules, rulesBucketConstructionStateList);
             return this.map;
@@ -35,18 +35,18 @@ namespace ts.formatting {
         }
 
         private GetRuleBucketIndex(row: number, column: number): number {
-            let rulesBucketIndex = (row * this.mapRowLength) + column;
-            //Debug.Assert(rulesBucketIndex < this.map.Length, "Trying to access an index outside the array.");
+            const rulesBucketIndex = (row * this.mapRowLength) + column;
+            // Debug.Assert(rulesBucketIndex < this.map.Length, "Trying to access an index outside the array.");
             return rulesBucketIndex;
         }
 
         private FillRule(rule: Rule, rulesBucketConstructionStateList: RulesBucketConstructionState[]): void {
-            let specificRule = rule.Descriptor.LeftTokenRange !== Shared.TokenRange.Any &&
+            const specificRule = rule.Descriptor.LeftTokenRange !== Shared.TokenRange.Any &&
                                rule.Descriptor.RightTokenRange !== Shared.TokenRange.Any;
 
             rule.Descriptor.LeftTokenRange.GetTokens().forEach((left) => {
                 rule.Descriptor.RightTokenRange.GetTokens().forEach((right) => {
-                    let rulesBucketIndex = this.GetRuleBucketIndex(left, right);
+                    const rulesBucketIndex = this.GetRuleBucketIndex(left, right);
 
                     let rulesBucket = this.map[rulesBucketIndex];
                     if (rulesBucket === undefined) {
@@ -54,26 +54,26 @@ namespace ts.formatting {
                     }
 
                     rulesBucket.AddRule(rule, specificRule, rulesBucketConstructionStateList, rulesBucketIndex);
-                })
-            })
+                });
+            });
         }
 
         public GetRule(context: FormattingContext): Rule {
-            let bucketIndex = this.GetRuleBucketIndex(context.currentTokenSpan.kind, context.nextTokenSpan.kind);
-            let bucket = this.map[bucketIndex];
-            if (bucket != null) {
-                for (let rule of bucket.Rules()) {
+            const bucketIndex = this.GetRuleBucketIndex(context.currentTokenSpan.kind, context.nextTokenSpan.kind);
+            const bucket = this.map[bucketIndex];
+            if (bucket) {
+                for (const rule of bucket.Rules()) {
                     if (rule.Operation.Context.InContext(context)) {
                         return rule;
                     }
                 }
             }
-            return null;
+            return undefined;
         }
     }
 
-    let MaskBitSize = 5;
-    let Mask = 0x1f;
+    const MaskBitSize = 5;
+    const Mask = 0x1f;
 
     export enum RulesPosition {
         IgnoreRulesSpecific = 0,
@@ -167,7 +167,7 @@ namespace ts.formatting {
             if (state === undefined) {
                 state = constructionState[rulesBucketIndex] = new RulesBucketConstructionState();
             }
-            let index = state.GetInsertionIndex(position);
+            const index = state.GetInsertionIndex(position);
             this.rules.splice(index, 0, rule);
             state.IncreaseInsertionIndex(position);
         }

src/services/formatting/rulesProvider.ts

@@ -25,10 +25,9 @@ namespace ts.formatting {
         }
 
         public ensureUpToDate(options: ts.FormatCodeOptions) {
-            // TODO: Should this be '==='?
-            if (this.options == null || !ts.compareDataObjects(this.options, options)) {
-                let activeRules = this.createActiveRules(options);
-                let rulesMap = RulesMap.create(activeRules);
+            if (!this.options || !ts.compareDataObjects(this.options, options)) {
+                const activeRules = this.createActiveRules(options);
+                const rulesMap = RulesMap.create(activeRules);
 
                 this.activeRules = activeRules;
                 this.rulesMap = rulesMap;

src/services/formatting/smartIndenter.ts

@@ -2,7 +2,7 @@
 
 /* @internal */
 namespace ts.formatting {
-    export module SmartIndenter {
+    export namespace SmartIndenter {
 
         const enum Value {
             Unknown = -1
@@ -19,18 +19,18 @@ namespace ts.formatting {
                 return 0;
             }
 
-            let precedingToken = findPrecedingToken(position, sourceFile);
+            const precedingToken = findPrecedingToken(position, sourceFile);
             if (!precedingToken) {
                 return 0;
             }
 
             // no indentation in string \regex\template literals
-            let precedingTokenIsLiteral = isStringOrRegularExpressionOrTemplateLiteral(precedingToken.kind);
+            const precedingTokenIsLiteral = isStringOrRegularExpressionOrTemplateLiteral(precedingToken.kind);
             if (precedingTokenIsLiteral && precedingToken.getStart(sourceFile) <= position && precedingToken.end > position) {
                 return 0;
             }
 
-            let lineAtPosition = sourceFile.getLineAndCharacterOfPosition(position).line;
+            const lineAtPosition = sourceFile.getLineAndCharacterOfPosition(position).line;
 
             // indentation is first non-whitespace character in a previous line
             // for block indentation, we should look for a line which contains something that's not
@@ -40,21 +40,21 @@ namespace ts.formatting {
                 // move backwards until we find a line with a non-whitespace character,
                 // then find the first non-whitespace character for that line.
                 let current = position;
-                while (current > 0){
-                    let char = sourceFile.text.charCodeAt(current);
+                while (current > 0) {
+                    const char = sourceFile.text.charCodeAt(current);
                     if (!isWhiteSpace(char) && !isLineBreak(char)) {
                         break;
                     }
                     current--;
                 }
 
-                let lineStart = ts.getLineStartPositionForPosition(current, sourceFile);
+                const lineStart = ts.getLineStartPositionForPosition(current, sourceFile);
                 return SmartIndenter.findFirstNonWhitespaceColumn(lineStart, current, sourceFile, options);
             }
 
             if (precedingToken.kind === SyntaxKind.CommaToken && precedingToken.parent.kind !== SyntaxKind.BinaryExpression) {
                 // previous token is comma that separates items in list - find the previous item and try to derive indentation from it
-                let actualIndentation = getActualIndentationForListItemBeforeComma(precedingToken, sourceFile, options);
+                const actualIndentation = getActualIndentationForListItemBeforeComma(precedingToken, sourceFile, options);
                 if (actualIndentation !== Value.Unknown) {
                     return actualIndentation;
                 }
@@ -104,7 +104,7 @@ namespace ts.formatting {
         }
 
         export function getIndentationForNode(n: Node, ignoreActualIndentationRange: TextRange, sourceFile: SourceFile, options: FormatCodeOptions): number {
-            let start = sourceFile.getLineAndCharacterOfPosition(n.getStart(sourceFile));
+            const start = sourceFile.getLineAndCharacterOfPosition(n.getStart(sourceFile));
             return getIndentationForNodeWorker(n, start, ignoreActualIndentationRange, /*indentationDelta*/ 0, sourceFile, options);
         }
 
@@ -124,19 +124,19 @@ namespace ts.formatting {
             while (parent) {
                 let useActualIndentation = true;
                 if (ignoreActualIndentationRange) {
-                    let start = current.getStart(sourceFile);
+                    const start = current.getStart(sourceFile);
                     useActualIndentation = start < ignoreActualIndentationRange.pos || start > ignoreActualIndentationRange.end;
                 }
 
                 if (useActualIndentation) {
                     // check if current node is a list item - if yes, take indentation from it
-                    let actualIndentation = getActualIndentationForListItem(current, sourceFile, options);
+                    const actualIndentation = getActualIndentationForListItem(current, sourceFile, options);
                     if (actualIndentation !== Value.Unknown) {
                         return actualIndentation + indentationDelta;
                     }
                 }
                 parentStart = getParentStart(parent, current, sourceFile);
-                let parentAndChildShareLine =
+                const parentAndChildShareLine =
                     parentStart.line === currentStart.line ||
                     childStartsOnTheSameLineWithElseInIfStatement(parent, current, currentStart.line, sourceFile);
 
@@ -167,7 +167,7 @@ namespace ts.formatting {
 
 
         function getParentStart(parent: Node, child: Node, sourceFile: SourceFile): LineAndCharacter {
-            let containingList = getContainingList(child, sourceFile);
+            const containingList = getContainingList(child, sourceFile);
             if (containingList) {
                 return sourceFile.getLineAndCharacterOfPosition(containingList.pos);
             }
@@ -180,7 +180,7 @@ namespace ts.formatting {
          */
         function getActualIndentationForListItemBeforeComma(commaToken: Node, sourceFile: SourceFile, options: EditorOptions): number {
             // previous token is comma that separates items in list - find the previous item and try to derive indentation from it
-            let commaItemInfo = findListItemInfo(commaToken);
+            const commaItemInfo = findListItemInfo(commaToken);
             if (commaItemInfo && commaItemInfo.listItemIndex > 0) {
                 return deriveActualIndentationFromList(commaItemInfo.list.getChildren(), commaItemInfo.listItemIndex - 1, sourceFile, options);
             }
@@ -203,7 +203,7 @@ namespace ts.formatting {
             // actual indentation is used for statements\declarations if one of cases below is true:
             // - parent is SourceFile - by default immediate children of SourceFile are not indented except when user indents them manually
             // - parent and child are not on the same line
-            let useActualIndentation =
+            const useActualIndentation =
                 (isDeclaration(current) || isStatement(current)) &&
                 (parent.kind === SyntaxKind.SourceFile || !parentAndChildShareLine);
 
@@ -215,7 +215,7 @@ namespace ts.formatting {
         }
 
         function nextTokenIsCurlyBraceOnSameLineAsCursor(precedingToken: Node, current: Node, lineAtPosition: number, sourceFile: SourceFile): boolean {
-            let nextToken = findNextToken(precedingToken, current);
+            const nextToken = findNextToken(precedingToken, current);
             if (!nextToken) {
                 return false;
             }
@@ -234,7 +234,7 @@ namespace ts.formatting {
                 // class A {
                 // $}
 
-                let nextTokenStartLine = getStartLineAndCharacterForNode(nextToken, sourceFile).line;
+                const nextTokenStartLine = getStartLineAndCharacterForNode(nextToken, sourceFile).line;
                 return lineAtPosition === nextTokenStartLine;
             }
 
@@ -247,10 +247,10 @@ namespace ts.formatting {
 
         export function childStartsOnTheSameLineWithElseInIfStatement(parent: Node, child: TextRangeWithKind, childStartLine: number, sourceFile: SourceFile): boolean {
             if (parent.kind === SyntaxKind.IfStatement && (<IfStatement>parent).elseStatement === child) {
-                let elseKeyword = findChildOfKind(parent, SyntaxKind.ElseKeyword, sourceFile);
+                const elseKeyword = findChildOfKind(parent, SyntaxKind.ElseKeyword, sourceFile);
                 Debug.assert(elseKeyword !== undefined);
 
-                let elseKeywordStartLine = getStartLineAndCharacterForNode(elseKeyword, sourceFile).line;
+                const elseKeywordStartLine = getStartLineAndCharacterForNode(elseKeyword, sourceFile).line;
                 return elseKeywordStartLine === childStartLine;
             }
 
@@ -277,7 +277,7 @@ namespace ts.formatting {
                     case SyntaxKind.MethodSignature:
                     case SyntaxKind.CallSignature:
                     case SyntaxKind.ConstructSignature: {
-                        let start = node.getStart(sourceFile);
+                        const start = node.getStart(sourceFile);
                         if ((<SignatureDeclaration>node.parent).typeParameters &&
                             rangeContainsStartEnd((<SignatureDeclaration>node.parent).typeParameters, start, node.getEnd())) {
                             return (<SignatureDeclaration>node.parent).typeParameters;
@@ -289,7 +289,7 @@ namespace ts.formatting {
                     }
                     case SyntaxKind.NewExpression:
                     case SyntaxKind.CallExpression: {
-                        let start = node.getStart(sourceFile);
+                        const start = node.getStart(sourceFile);
                         if ((<CallExpression>node.parent).typeArguments &&
                             rangeContainsStartEnd((<CallExpression>node.parent).typeArguments, start, node.getEnd())) {
                             return (<CallExpression>node.parent).typeArguments;
@@ -306,11 +306,11 @@ namespace ts.formatting {
         }
 
         function getActualIndentationForListItem(node: Node, sourceFile: SourceFile, options: EditorOptions): number {
-            let containingList = getContainingList(node, sourceFile);
+            const containingList = getContainingList(node, sourceFile);
             return containingList ? getActualIndentationFromList(containingList) : Value.Unknown;
 
             function getActualIndentationFromList(list: Node[]): number {
-                let index = indexOf(list, node);
+                const index = indexOf(list, node);
                 return index !== -1 ? deriveActualIndentationFromList(list, index, sourceFile, options) : Value.Unknown;
             }
         }
@@ -327,15 +327,15 @@ namespace ts.formatting {
                 node.parent.kind === SyntaxKind.NewExpression) &&
                 (<CallExpression>node.parent).expression !== node) {
 
-                let fullCallOrNewExpression = (<CallExpression | NewExpression>node.parent).expression;
-                let startingExpression = getStartingExpression(<PropertyAccessExpression | CallExpression | ElementAccessExpression>fullCallOrNewExpression);
+                const fullCallOrNewExpression = (<CallExpression | NewExpression>node.parent).expression;
+                const startingExpression = getStartingExpression(<PropertyAccessExpression | CallExpression | ElementAccessExpression>fullCallOrNewExpression);
 
                 if (fullCallOrNewExpression === startingExpression) {
                     return Value.Unknown;
                 }
 
-                let fullCallOrNewExpressionEnd = sourceFile.getLineAndCharacterOfPosition(fullCallOrNewExpression.end);
-                let startingExpressionEnd = sourceFile.getLineAndCharacterOfPosition(startingExpression.end);
+                const fullCallOrNewExpressionEnd = sourceFile.getLineAndCharacterOfPosition(fullCallOrNewExpression.end);
+                const startingExpressionEnd = sourceFile.getLineAndCharacterOfPosition(startingExpression.end);
 
                 if (fullCallOrNewExpressionEnd.line === startingExpressionEnd.line) {
                     return Value.Unknown;
@@ -365,17 +365,17 @@ namespace ts.formatting {
 
         function deriveActualIndentationFromList(list: Node[], index: number, sourceFile: SourceFile, options: EditorOptions): number {
             Debug.assert(index >= 0 && index < list.length);
-            let node = list[index];
+            const node = list[index];
 
             // 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]
             let lineAndCharacter = getStartLineAndCharacterForNode(node, sourceFile);
-            for (let i = index - 1; i >= 0; --i) {
+            for (let i = index - 1; i >= 0; i--) {
                 if (list[i].kind === SyntaxKind.CommaToken) {
                     continue;
                 }
                 // skip list items that ends on the same line with the current list element
-                let prevEndLine = sourceFile.getLineAndCharacterOfPosition(list[i].end).line;
+                const prevEndLine = sourceFile.getLineAndCharacterOfPosition(list[i].end).line;
                 if (prevEndLine !== lineAndCharacter.line) {
                     return findColumnForFirstNonWhitespaceCharacterInLine(lineAndCharacter, sourceFile, options);
                 }
@@ -386,7 +386,7 @@ namespace ts.formatting {
         }
 
         function findColumnForFirstNonWhitespaceCharacterInLine(lineAndCharacter: LineAndCharacter, sourceFile: SourceFile, options: EditorOptions): number {
-            let lineStart = sourceFile.getPositionOfLineAndCharacter(lineAndCharacter.line, 0);
+            const lineStart = sourceFile.getPositionOfLineAndCharacter(lineAndCharacter.line, 0);
             return findFirstNonWhitespaceColumn(lineStart, lineStart + lineAndCharacter.character, sourceFile, options);
         }
 
@@ -400,8 +400,8 @@ namespace ts.formatting {
         export function findFirstNonWhitespaceCharacterAndColumn(startPos: number, endPos: number, sourceFile: SourceFile, options: EditorOptions) {
             let character = 0;
             let column = 0;
-            for (let pos = startPos; pos < endPos; ++pos) {
-                let ch = sourceFile.text.charCodeAt(pos);
+            for (let pos = startPos; pos < endPos; pos++) {
+                const ch = sourceFile.text.charCodeAt(pos);
                 if (!isWhiteSpace(ch)) {
                     break;
                 }
@@ -467,10 +467,10 @@ namespace ts.formatting {
             }
             return false;
         }
-        
+
         /* @internal */
         export function nodeWillIndentChild(parent: TextRangeWithKind, child: TextRangeWithKind, indentByDefault: boolean) {
-            let childKind = child ? child.kind : SyntaxKind.Unknown;
+            const childKind = child ? child.kind : SyntaxKind.Unknown;
             switch (parent.kind) {
                 case SyntaxKind.DoStatement:
                 case SyntaxKind.WhileStatement:
@@ -497,7 +497,7 @@ namespace ts.formatting {
         Function returns true when the parent node should indent the given child by an explicit rule
         */
         export function shouldIndentChildNode(parent: TextRangeWithKind, child?: TextRangeWithKind): boolean {
-            return nodeContentIsAlwaysIndented(parent.kind) || nodeWillIndentChild(parent, child, false); 
+            return nodeContentIsAlwaysIndented(parent.kind) || nodeWillIndentChild(parent, child, /*indentByDefault*/ false);
         }
     }
 }

src/services/formatting/tokenRange.ts

@@ -2,7 +2,7 @@
 
 /* @internal */
 namespace ts.formatting {
-    export module Shared {
+    export namespace Shared {
         export interface ITokenAccess {
             GetTokens(): SyntaxKind[];
             Contains(token: SyntaxKind): boolean;
@@ -60,7 +60,7 @@ namespace ts.formatting {
 
         export class TokenAllAccess implements ITokenAccess {
             public GetTokens(): SyntaxKind[] {
-                let result: SyntaxKind[] = [];
+                const result: SyntaxKind[] = [];
                 for (let token = SyntaxKind.FirstToken; token <= SyntaxKind.LastToken; token++) {
                     result.push(token);
                 }

src/services/navigationBar.ts

@@ -323,6 +323,10 @@ namespace ts.NavigationBar {
                 case SyntaxKind.ModuleDeclaration:
                     return createItem(node, getModuleName(<ModuleDeclaration>node), ts.ScriptElementKind.moduleElement);
 
+                case SyntaxKind.InterfaceDeclaration:
+                    return createItem(node, getTextOfNode((<InterfaceDeclaration>node).name), ts.ScriptElementKind.interfaceElement);
+
+
                 case SyntaxKind.CallSignature:
                     return createItem(node, "()", ts.ScriptElementKind.callSignatureElement);
 
@@ -333,6 +337,9 @@ namespace ts.NavigationBar {
                 case SyntaxKind.PropertySignature:
                     return createItem(node, getTextOfNode((<PropertyDeclaration>node).name), ts.ScriptElementKind.memberVariableElement);
 
+                case SyntaxKind.ClassDeclaration:
+                    return createItem(node, getTextOfNode((<ClassDeclaration>node).name), ts.ScriptElementKind.classElement);
+
                 case SyntaxKind.FunctionDeclaration:
                     return createItem(node, getTextOfNode((<FunctionLikeDeclaration>node).name), ts.ScriptElementKind.functionElement);
 

src/services/signatureHelp.ts

@@ -7,7 +7,7 @@ namespace ts.SignatureHelp {
     // 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)) {
@@ -125,9 +125,9 @@ namespace ts.SignatureHelp {
     //    }
 
     //    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();
     //    }
@@ -161,8 +161,8 @@ namespace ts.SignatureHelp {
 
     //    // Did not find matching token
     //    return null;
-    //}
-    let emptyArray: any[] = [];
+    // }
+    const emptyArray: any[] = [];
 
     const enum ArgumentListKind {
         TypeArguments,
@@ -179,16 +179,16 @@ namespace ts.SignatureHelp {
     }
 
     export function getSignatureHelpItems(program: Program, sourceFile: SourceFile, position: number, cancellationToken: CancellationToken): SignatureHelpItems {
-        let typeChecker = program.getTypeChecker();
+        const typeChecker = program.getTypeChecker();
 
         // Decide whether to show signature help
-        let startingToken = findTokenOnLeftOfPosition(sourceFile, position);
+        const startingToken = findTokenOnLeftOfPosition(sourceFile, position);
         if (!startingToken) {
             // We are at the beginning of the file
             return undefined;
         }
 
-        let argumentInfo = getContainingArgumentInfo(startingToken);
+        const argumentInfo = getContainingArgumentInfo(startingToken);
         cancellationToken.throwIfCancellationRequested();
 
         // Semantic filtering of signature help
@@ -196,9 +196,9 @@ namespace ts.SignatureHelp {
             return undefined;
         }
 
-        let call = argumentInfo.invocation;
-        let candidates = <Signature[]>[];
-        let resolvedSignature = typeChecker.getResolvedSignature(call, candidates);
+        const call = argumentInfo.invocation;
+        const candidates = <Signature[]>[];
+        const resolvedSignature = typeChecker.getResolvedSignature(call, candidates);
         cancellationToken.throwIfCancellationRequested();
 
         if (!candidates.length) {
@@ -219,9 +219,9 @@ namespace ts.SignatureHelp {
             }
 
             // See if we can find some symbol with the call expression name that has call signatures.
-            let callExpression = <CallExpression>argumentInfo.invocation;
-            let expression = callExpression.expression;
-            let name = expression.kind === SyntaxKind.Identifier
+            const callExpression = <CallExpression>argumentInfo.invocation;
+            const expression = callExpression.expression;
+            const name = expression.kind === SyntaxKind.Identifier
                 ? <Identifier> expression
                 : expression.kind === SyntaxKind.PropertyAccessExpression
                     ? (<PropertyAccessExpression>expression).name
@@ -231,18 +231,18 @@ namespace ts.SignatureHelp {
                 return undefined;
             }
 
-            let typeChecker = program.getTypeChecker();
-            for (let sourceFile of program.getSourceFiles()) {
-                let nameToDeclarations = sourceFile.getNamedDeclarations();
-                let declarations = getProperty(nameToDeclarations, name.text);
+            const typeChecker = program.getTypeChecker();
+            for (const sourceFile of program.getSourceFiles()) {
+                const nameToDeclarations = sourceFile.getNamedDeclarations();
+                const declarations = getProperty(nameToDeclarations, name.text);
 
                 if (declarations) {
-                    for (let declaration of declarations) {
-                        let symbol = declaration.symbol;
+                    for (const declaration of declarations) {
+                        const symbol = declaration.symbol;
                         if (symbol) {
-                            let type = typeChecker.getTypeOfSymbolAtLocation(symbol, declaration);
+                            const type = typeChecker.getTypeOfSymbolAtLocation(symbol, declaration);
                             if (type) {
-                                let callSignatures = type.getCallSignatures();
+                                const callSignatures = type.getCallSignatures();
                                 if (callSignatures && callSignatures.length) {
                                     return createSignatureHelpItems(callSignatures, callSignatures[0], argumentInfo);
                                 }
@@ -259,7 +259,7 @@ namespace ts.SignatureHelp {
          */
         function getImmediatelyContainingArgumentInfo(node: Node): ArgumentListInfo {
             if (node.parent.kind === SyntaxKind.CallExpression || node.parent.kind === SyntaxKind.NewExpression) {
-                let callExpression = <CallExpression>node.parent;
+                const callExpression = <CallExpression>node.parent;
                 // There are 3 cases to handle:
                 //   1. The token introduces a list, and should begin a sig help session
                 //   2. The token is either not associated with a list, or ends a list, so the session should end
@@ -278,8 +278,8 @@ namespace ts.SignatureHelp {
                     node.kind === SyntaxKind.OpenParenToken) {
                     // Find the list that starts right *after* the < or ( token.
                     // If the user has just opened a list, consider this item 0.
-                    let list = getChildListThatStartsWithOpenerToken(callExpression, node, sourceFile);
-                    let isTypeArgList = callExpression.typeArguments && callExpression.typeArguments.pos === list.pos;
+                    const list = getChildListThatStartsWithOpenerToken(callExpression, node, sourceFile);
+                    const isTypeArgList = callExpression.typeArguments && callExpression.typeArguments.pos === list.pos;
                     Debug.assert(list !== undefined);
                     return {
                         kind: isTypeArgList ? ArgumentListKind.TypeArguments : ArgumentListKind.CallArguments,
@@ -296,16 +296,16 @@ namespace ts.SignatureHelp {
                 //   - Between the type arguments and the arguments (greater than token)
                 //   - On the target of the call (parent.func)
                 //   - On the 'new' keyword in a 'new' expression
-                let listItemInfo = findListItemInfo(node);
+                const listItemInfo = findListItemInfo(node);
                 if (listItemInfo) {
-                    let list = listItemInfo.list;
-                    let isTypeArgList = callExpression.typeArguments && callExpression.typeArguments.pos === list.pos;
+                    const list = listItemInfo.list;
+                    const isTypeArgList = callExpression.typeArguments && callExpression.typeArguments.pos === list.pos;
 
-                    let argumentIndex = getArgumentIndex(list, node);
-                    let argumentCount = getArgumentCount(list);
+                    const argumentIndex = getArgumentIndex(list, node);
+                    const argumentCount = getArgumentCount(list);
 
                     Debug.assert(argumentIndex === 0 || argumentIndex < argumentCount,
-                        `argumentCount < argumentIndex, ${argumentCount} < ${argumentIndex}`); 
+                        `argumentCount < argumentIndex, ${argumentCount} < ${argumentIndex}`);
 
                     return {
                         kind: isTypeArgList ? ArgumentListKind.TypeArguments : ArgumentListKind.CallArguments,
@@ -324,18 +324,18 @@ namespace ts.SignatureHelp {
                 }
             }
             else if (node.kind === SyntaxKind.TemplateHead && node.parent.parent.kind === SyntaxKind.TaggedTemplateExpression) {
-                let templateExpression = <TemplateExpression>node.parent;
-                let tagExpression = <TaggedTemplateExpression>templateExpression.parent;
+                const templateExpression = <TemplateExpression>node.parent;
+                const tagExpression = <TaggedTemplateExpression>templateExpression.parent;
                 Debug.assert(templateExpression.kind === SyntaxKind.TemplateExpression);
 
-                let argumentIndex = isInsideTemplateLiteral(<LiteralExpression>node, position) ? 0 : 1;
+                const argumentIndex = isInsideTemplateLiteral(<LiteralExpression>node, position) ? 0 : 1;
 
                 return getArgumentListInfoForTemplate(tagExpression, argumentIndex);
             }
             else if (node.parent.kind === SyntaxKind.TemplateSpan && node.parent.parent.parent.kind === SyntaxKind.TaggedTemplateExpression) {
-                let templateSpan = <TemplateSpan>node.parent;
-                let templateExpression = <TemplateExpression>templateSpan.parent;
-                let tagExpression = <TaggedTemplateExpression>templateExpression.parent;
+                const templateSpan = <TemplateSpan>node.parent;
+                const templateExpression = <TemplateExpression>templateSpan.parent;
+                const tagExpression = <TaggedTemplateExpression>templateExpression.parent;
                 Debug.assert(templateExpression.kind === SyntaxKind.TemplateExpression);
 
                 // If we're just after a template tail, don't show signature help.
@@ -343,12 +343,12 @@ namespace ts.SignatureHelp {
                     return undefined;
                 }
 
-                let spanIndex = templateExpression.templateSpans.indexOf(templateSpan);
-                let argumentIndex = getArgumentIndexForTemplatePiece(spanIndex, node);
+                const spanIndex = templateExpression.templateSpans.indexOf(templateSpan);
+                const argumentIndex = getArgumentIndexForTemplatePiece(spanIndex, node);
 
                 return getArgumentListInfoForTemplate(tagExpression, argumentIndex);
             }
-            
+
             return undefined;
         }
 
@@ -365,8 +365,8 @@ namespace ts.SignatureHelp {
             // that trailing comma in the list, and we'll have generated the appropriate
             // arg index.
             let argumentIndex = 0;
-            let listChildren = argumentsList.getChildren();
-            for (let child of listChildren) {
+            const listChildren = argumentsList.getChildren();
+            for (const child of listChildren) {
                 if (child === node) {
                     break;
                 }
@@ -390,7 +390,7 @@ namespace ts.SignatureHelp {
             // we'll have:  'a' '<comma>' '<missing>' 
             // That will give us 2 non-commas.  We then add one for the last comma, givin us an
             // arg count of 3.
-            let listChildren = argumentsList.getChildren();
+            const listChildren = argumentsList.getChildren();
 
             let argumentCount = countWhere(listChildren, arg => arg.kind !== SyntaxKind.CommaToken);
             if (listChildren.length > 0 && lastOrUndefined(listChildren).kind === SyntaxKind.CommaToken) {
@@ -426,11 +426,11 @@ namespace ts.SignatureHelp {
 
         function getArgumentListInfoForTemplate(tagExpression: TaggedTemplateExpression, argumentIndex: number): ArgumentListInfo {
             // argumentCount is either 1 or (numSpans + 1) to account for the template strings array argument.
-            let argumentCount = tagExpression.template.kind === SyntaxKind.NoSubstitutionTemplateLiteral
+            const argumentCount = tagExpression.template.kind === SyntaxKind.NoSubstitutionTemplateLiteral
                 ? 1
                 : (<TemplateExpression>tagExpression.template).templateSpans.length + 1;
 
-            Debug.assert(argumentIndex === 0 || argumentIndex < argumentCount, `argumentCount < argumentIndex, ${argumentCount} < ${argumentIndex}`); 
+            Debug.assert(argumentIndex === 0 || argumentIndex < argumentCount, `argumentCount < argumentIndex, ${argumentCount} < ${argumentIndex}`);
 
             return {
                 kind: ArgumentListKind.TaggedTemplateArguments,
@@ -450,14 +450,14 @@ namespace ts.SignatureHelp {
             //
             // The applicable span is from the first bar to the second bar (inclusive,
             // but not including parentheses)
-            let applicableSpanStart = argumentsList.getFullStart();
-            let applicableSpanEnd = skipTrivia(sourceFile.text, argumentsList.getEnd(), /*stopAfterLineBreak*/ false);
+            const applicableSpanStart = argumentsList.getFullStart();
+            const applicableSpanEnd = skipTrivia(sourceFile.text, argumentsList.getEnd(), /*stopAfterLineBreak*/ false);
             return createTextSpan(applicableSpanStart, applicableSpanEnd - applicableSpanStart);
         }
 
         function getApplicableSpanForTaggedTemplate(taggedTemplate: TaggedTemplateExpression): TextSpan {
-            let template = taggedTemplate.template;
-            let applicableSpanStart = template.getStart();
+            const template = taggedTemplate.template;
+            const applicableSpanStart = template.getStart();
             let applicableSpanEnd = template.getEnd();
 
             // We need to adjust the end position for the case where the template does not have a tail.
@@ -470,7 +470,7 @@ namespace ts.SignatureHelp {
             // This is because a Missing node has no width. However, what we actually want is to include trivia
             // leading up to the next token in case the user is about to type in a TemplateMiddle or TemplateTail.
             if (template.kind === SyntaxKind.TemplateExpression) {
-                let lastSpan = lastOrUndefined((<TemplateExpression>template).templateSpans);
+                const lastSpan = lastOrUndefined((<TemplateExpression>template).templateSpans);
                 if (lastSpan.literal.getFullWidth() === 0) {
                     applicableSpanEnd = skipTrivia(sourceFile.text, applicableSpanEnd, /*stopAfterLineBreak*/ false);
                 }
@@ -491,7 +491,7 @@ namespace ts.SignatureHelp {
                     Debug.fail("Node of kind " + n.kind + " is not a subspan of its parent of kind " + n.parent.kind);
                 }
 
-                let argumentInfo = getImmediatelyContainingArgumentInfo(n);
+                const argumentInfo = getImmediatelyContainingArgumentInfo(n);
                 if (argumentInfo) {
                     return argumentInfo;
                 }
@@ -503,8 +503,8 @@ namespace ts.SignatureHelp {
         }
 
         function getChildListThatStartsWithOpenerToken(parent: Node, openerToken: Node, sourceFile: SourceFile): Node {
-            let children = parent.getChildren(sourceFile);
-            let indexOfOpenerToken = children.indexOf(openerToken);
+            const children = parent.getChildren(sourceFile);
+            const indexOfOpenerToken = children.indexOf(openerToken);
             Debug.assert(indexOfOpenerToken >= 0 && children.length > indexOfOpenerToken + 1);
             return children[indexOfOpenerToken + 1];
         }
@@ -521,7 +521,7 @@ namespace ts.SignatureHelp {
             let maxParamsSignatureIndex = -1;
             let maxParams = -1;
             for (let i = 0; i < candidates.length; i++) {
-                let candidate = candidates[i];
+                const candidate = candidates[i];
 
                 if (candidate.hasRestParameter || candidate.parameters.length >= argumentCount) {
                     return i;
@@ -537,17 +537,17 @@ namespace ts.SignatureHelp {
         }
 
         function createSignatureHelpItems(candidates: Signature[], bestSignature: Signature, argumentListInfo: ArgumentListInfo): SignatureHelpItems {
-            let applicableSpan = argumentListInfo.argumentsSpan;
-            let isTypeParameterList = argumentListInfo.kind === ArgumentListKind.TypeArguments;
+            const applicableSpan = argumentListInfo.argumentsSpan;
+            const isTypeParameterList = argumentListInfo.kind === ArgumentListKind.TypeArguments;
 
-            let invocation = argumentListInfo.invocation;
-            let callTarget = getInvokedExpression(invocation)
-            let callTargetSymbol = typeChecker.getSymbolAtLocation(callTarget);
-            let callTargetDisplayParts = callTargetSymbol && symbolToDisplayParts(typeChecker, callTargetSymbol, /*enclosingDeclaration*/ undefined, /*meaning*/ undefined);
-            let items: SignatureHelpItem[] = map(candidates, candidateSignature => {
+            const invocation = argumentListInfo.invocation;
+            const callTarget = getInvokedExpression(invocation);
+            const callTargetSymbol = typeChecker.getSymbolAtLocation(callTarget);
+            const callTargetDisplayParts = callTargetSymbol && symbolToDisplayParts(typeChecker, callTargetSymbol, /*enclosingDeclaration*/ undefined, /*meaning*/ undefined);
+            const items: SignatureHelpItem[] = map(candidates, candidateSignature => {
                 let signatureHelpParameters: SignatureHelpParameter[];
-                let prefixDisplayParts: SymbolDisplayPart[] = [];
-                let suffixDisplayParts: SymbolDisplayPart[] = [];
+                const prefixDisplayParts: SymbolDisplayPart[] = [];
+                const suffixDisplayParts: SymbolDisplayPart[] = [];
 
                 if (callTargetDisplayParts) {
                     addRange(prefixDisplayParts, callTargetDisplayParts);
@@ -555,28 +555,28 @@ namespace ts.SignatureHelp {
 
                 if (isTypeParameterList) {
                     prefixDisplayParts.push(punctuationPart(SyntaxKind.LessThanToken));
-                    let typeParameters = candidateSignature.typeParameters;
+                    const typeParameters = candidateSignature.typeParameters;
                     signatureHelpParameters = typeParameters && typeParameters.length > 0 ? map(typeParameters, createSignatureHelpParameterForTypeParameter) : emptyArray;
                     suffixDisplayParts.push(punctuationPart(SyntaxKind.GreaterThanToken));
-                    let parameterParts = mapToDisplayParts(writer =>
+                    const parameterParts = mapToDisplayParts(writer =>
                         typeChecker.getSymbolDisplayBuilder().buildDisplayForParametersAndDelimiters(candidateSignature.thisType, candidateSignature.parameters, writer, invocation));
                     addRange(suffixDisplayParts, parameterParts);
                 }
                 else {
-                    let typeParameterParts = mapToDisplayParts(writer =>
+                    const typeParameterParts = mapToDisplayParts(writer =>
                         typeChecker.getSymbolDisplayBuilder().buildDisplayForTypeParametersAndDelimiters(candidateSignature.typeParameters, writer, invocation));
                     addRange(prefixDisplayParts, typeParameterParts);
                     prefixDisplayParts.push(punctuationPart(SyntaxKind.OpenParenToken));
 
-                    let parameters = candidateSignature.parameters;
+                    const parameters = candidateSignature.parameters;
                     signatureHelpParameters = parameters.length > 0 ? map(parameters, createSignatureHelpParameterForParameter) : emptyArray;
                     suffixDisplayParts.push(punctuationPart(SyntaxKind.CloseParenToken));
                 }
 
-                let returnTypeParts = mapToDisplayParts(writer =>
+                const returnTypeParts = mapToDisplayParts(writer =>
                     typeChecker.getSymbolDisplayBuilder().buildReturnTypeDisplay(candidateSignature, writer, invocation));
                 addRange(suffixDisplayParts, returnTypeParts);
-                
+
                 return {
                     isVariadic: candidateSignature.hasRestParameter,
                     prefixDisplayParts,
@@ -587,17 +587,17 @@ namespace ts.SignatureHelp {
                 };
             });
 
-            let argumentIndex = argumentListInfo.argumentIndex;
+            const argumentIndex = argumentListInfo.argumentIndex;
 
             // argumentCount is the *apparent* number of arguments.
-            let argumentCount = argumentListInfo.argumentCount;
+            const argumentCount = argumentListInfo.argumentCount;
 
             let selectedItemIndex = candidates.indexOf(bestSignature);
             if (selectedItemIndex < 0) {
                 selectedItemIndex = selectBestInvalidOverloadIndex(candidates, argumentCount);
             }
 
-            Debug.assert(argumentIndex === 0 || argumentIndex < argumentCount, `argumentCount < argumentIndex, ${argumentCount} < ${argumentIndex}`); 
+            Debug.assert(argumentIndex === 0 || argumentIndex < argumentCount, `argumentCount < argumentIndex, ${argumentCount} < ${argumentIndex}`);
 
             return {
                 items,
@@ -608,7 +608,7 @@ namespace ts.SignatureHelp {
             };
 
             function createSignatureHelpParameterForParameter(parameter: Symbol): SignatureHelpParameter {
-                let displayParts = mapToDisplayParts(writer =>
+                const displayParts = mapToDisplayParts(writer =>
                     typeChecker.getSymbolDisplayBuilder().buildParameterDisplay(parameter, writer, invocation));
 
                 return {
@@ -620,7 +620,7 @@ namespace ts.SignatureHelp {
             }
 
             function createSignatureHelpParameterForTypeParameter(typeParameter: TypeParameter): SignatureHelpParameter {
-                let displayParts = mapToDisplayParts(writer =>
+                const displayParts = mapToDisplayParts(writer =>
                     typeChecker.getSymbolDisplayBuilder().buildTypeParameterDisplay(typeParameter, writer, invocation));
 
                 return {

src/services/utilities.ts

@@ -7,8 +7,8 @@ namespace ts {
     }
 
     export function getLineStartPositionForPosition(position: number, sourceFile: SourceFile): number {
-        let lineStarts = sourceFile.getLineStarts();
-        let line = sourceFile.getLineAndCharacterOfPosition(position).line;
+        const lineStarts = sourceFile.getLineStarts();
+        const line = sourceFile.getLineAndCharacterOfPosition(position).line;
         return lineStarts[line];
     }
 
@@ -29,8 +29,8 @@ namespace ts {
     }
 
     export function startEndOverlapsWithStartEnd(start1: number, end1: number, start2: number, end2: number) {
-        let start = Math.max(start1, start2);
-        let end = Math.min(end1, end2);
+        const start = Math.max(start1, start2);
+        const end = Math.min(end1, end2);
         return start < end;
     }
 
@@ -131,7 +131,7 @@ namespace ts {
                 return isCompletedNode((<IterationStatement>n).statement, sourceFile);
             case SyntaxKind.DoStatement:
                 // rough approximation: if DoStatement has While keyword - then if node is completed is checking the presence of ')';
-                let hasWhileKeyword = findChildOfKind(n, SyntaxKind.WhileKeyword, sourceFile);
+                const hasWhileKeyword = findChildOfKind(n, SyntaxKind.WhileKeyword, sourceFile);
                 if (hasWhileKeyword) {
                     return nodeEndsWith(n, SyntaxKind.CloseParenToken, sourceFile);
                 }
@@ -145,13 +145,13 @@ namespace ts {
             case SyntaxKind.VoidExpression:
             case SyntaxKind.YieldExpression:
             case SyntaxKind.SpreadElementExpression:
-                let unaryWordExpression = (<TypeOfExpression | DeleteExpression | VoidExpression | YieldExpression | SpreadElementExpression>n);
+                const unaryWordExpression = (<TypeOfExpression | DeleteExpression | VoidExpression | YieldExpression | SpreadElementExpression>n);
                 return isCompletedNode(unaryWordExpression.expression, sourceFile);
 
             case SyntaxKind.TaggedTemplateExpression:
                 return isCompletedNode((<TaggedTemplateExpression>n).template, sourceFile);
             case SyntaxKind.TemplateExpression:
-                let lastSpan = lastOrUndefined((<TemplateExpression>n).templateSpans);
+                const lastSpan = lastOrUndefined((<TemplateExpression>n).templateSpans);
                 return isCompletedNode(lastSpan, sourceFile);
             case SyntaxKind.TemplateSpan:
                 return nodeIsPresent((<TemplateSpan>n).literal);
@@ -173,9 +173,9 @@ namespace ts {
      * If child at position 'length - 1' is 'SemicolonToken' it is skipped and 'expectedLastToken' is compared with child at position 'length - 2'.
      */
     function nodeEndsWith(n: Node, expectedLastToken: SyntaxKind, sourceFile: SourceFile): boolean {
-        let children = n.getChildren(sourceFile);
+        const children = n.getChildren(sourceFile);
         if (children.length) {
-            let last = lastOrUndefined(children);
+            const last = lastOrUndefined(children);
             if (last.kind === expectedLastToken) {
                 return true;
             }
@@ -187,7 +187,7 @@ namespace ts {
     }
 
     export function findListItemInfo(node: Node): ListItemInfo {
-        let list = findContainingList(node);
+        const list = findContainingList(node);
 
         // It is possible at this point for syntaxList to be undefined, either if
         // node.parent had no list child, or if none of its list children contained
@@ -197,8 +197,8 @@ namespace ts {
             return undefined;
         }
 
-        let children = list.getChildren();
-        let listItemIndex = indexOf(children, node);
+        const children = list.getChildren();
+        const listItemIndex = indexOf(children, node);
 
         return {
             listItemIndex,
@@ -219,7 +219,7 @@ namespace ts {
         // be parented by the container of the SyntaxList, not the SyntaxList itself.
         // In order to find the list item index, we first need to locate SyntaxList itself and then search
         // for the position of the relevant node (or comma).
-        let syntaxList = forEach(node.parent.getChildren(), c => {
+        const syntaxList = forEach(node.parent.getChildren(), c => {
             // find syntax list that covers the span of the node
             if (c.kind === SyntaxKind.SyntaxList && c.pos <= node.pos && c.end >= node.end) {
                 return c;
@@ -266,16 +266,16 @@ namespace ts {
 
             // find the child that contains 'position'
             for (let i = 0, n = current.getChildCount(sourceFile); i < n; i++) {
-                let child = current.getChildAt(i);
-                let start = allowPositionInLeadingTrivia ? child.getFullStart() : child.getStart(sourceFile);
+                const child = current.getChildAt(i);
+                const start = allowPositionInLeadingTrivia ? child.getFullStart() : child.getStart(sourceFile);
                 if (start <= position) {
-                    let end = child.getEnd();
+                    const end = child.getEnd();
                     if (position < end || (position === end && child.kind === SyntaxKind.EndOfFileToken)) {
                         current = child;
                         continue outer;
                     }
                     else if (includeItemAtEndPosition && end === position) {
-                        let previousToken = findPrecedingToken(position, sourceFile, child);
+                        const previousToken = findPrecedingToken(position, sourceFile, child);
                         if (previousToken && includeItemAtEndPosition(previousToken)) {
                             return previousToken;
                         }
@@ -297,7 +297,7 @@ namespace ts {
     export function findTokenOnLeftOfPosition(file: SourceFile, position: number): Node {
         // Ideally, getTokenAtPosition should return a token. However, it is currently
         // broken, so we do a check to make sure the result was indeed a token.
-        let tokenAtPosition = getTokenAtPosition(file, position);
+        const tokenAtPosition = getTokenAtPosition(file, position);
         if (isToken(tokenAtPosition) && position > tokenAtPosition.getStart(file) && position < tokenAtPosition.getEnd()) {
             return tokenAtPosition;
         }
@@ -314,9 +314,9 @@ namespace ts {
                 return n;
             }
 
-            let children = n.getChildren();
-            for (let child of children) {
-                let shouldDiveInChildNode =
+            const children = n.getChildren();
+            for (const child of children) {
+                const shouldDiveInChildNode =
                     // previous token is enclosed somewhere in the child
                     (child.pos <= previousToken.pos && child.end > previousToken.end) ||
                     // previous token ends exactly at the beginning of child
@@ -339,8 +339,8 @@ namespace ts {
                 return n;
             }
 
-            let children = n.getChildren();
-            let candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ children.length);
+            const children = n.getChildren();
+            const candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ children.length);
             return candidate && findRightmostToken(candidate);
 
         }
@@ -352,7 +352,7 @@ namespace ts {
 
             const children = n.getChildren();
             for (let i = 0, len = children.length; i < len; i++) {
-                let child = children[i];
+                const child = children[i];
                 // condition 'position < child.end' checks if child node end after the position
                 // in the example below this condition will be false for 'aaaa' and 'bbbb' and true for 'ccc'
                 // aaaa___bbbb___$__ccc
@@ -369,7 +369,7 @@ namespace ts {
 
                     if (lookInPreviousChild) {
                         // actual start of the node is past the position - previous token should be at the end of previous child
-                        let candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ i);
+                        const candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ i);
                         return candidate && findRightmostToken(candidate);
                     }
                     else {
@@ -386,14 +386,14 @@ namespace ts {
             // Try to find the rightmost token in the file without filtering.
             // Namely we are skipping the check: 'position < node.end'
             if (children.length) {
-                let candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ children.length);
+                const candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ children.length);
                 return candidate && findRightmostToken(candidate);
             }
         }
 
         /// finds last node that is considered as candidate for search (isCandidate(node) === true) starting from 'exclusiveStartPosition'
         function findRightmostChildNodeWithTokens(children: Node[], exclusiveStartPosition: number): Node {
-            for (let i = exclusiveStartPosition - 1; i >= 0; --i) {
+            for (let i = exclusiveStartPosition - 1; i >= 0; i--) {
                 if (nodeHasTokens(children[i])) {
                     return children[i];
                 }
@@ -402,7 +402,7 @@ namespace ts {
     }
 
     export function isInString(sourceFile: SourceFile, position: number) {
-        let token = getTokenAtPosition(sourceFile, position);
+        const token = getTokenAtPosition(sourceFile, position);
         return token && (token.kind === SyntaxKind.StringLiteral || token.kind === SyntaxKind.StringLiteralType) && position > token.getStart(sourceFile);
     }
 
@@ -414,7 +414,7 @@ namespace ts {
      * returns true if the position is in between the open and close elements of an JSX expression.
      */
     export function isInsideJsxElementOrAttribute(sourceFile: SourceFile, position: number) {
-        let token = getTokenAtPosition(sourceFile, position);
+        const token = getTokenAtPosition(sourceFile, position);
 
         if (!token) {
             return false;
@@ -446,7 +446,7 @@ namespace ts {
     }
 
     export function isInTemplateString(sourceFile: SourceFile, position: number) {
-        let token = getTokenAtPosition(sourceFile, position);
+        const token = getTokenAtPosition(sourceFile, position);
         return isTemplateLiteralKind(token.kind) && position > token.getStart(sourceFile);
     }
 
@@ -455,10 +455,10 @@ namespace ts {
      * satisfies predicate, and false otherwise.
      */
     export function isInCommentHelper(sourceFile: SourceFile, position: number, predicate?: (c: CommentRange) => boolean): boolean {
-        let token = getTokenAtPosition(sourceFile, position);
+        const token = getTokenAtPosition(sourceFile, position);
 
         if (token && position <= token.getStart(sourceFile)) {
-            let commentRanges = getLeadingCommentRanges(sourceFile.text, token.pos);
+            const commentRanges = getLeadingCommentRanges(sourceFile.text, token.pos);
 
             // The end marker of a single-line comment does not include the newline character.
             // In the following case, we are inside a comment (^ denotes the cursor position):
@@ -482,10 +482,10 @@ namespace ts {
     }
 
     export function hasDocComment(sourceFile: SourceFile, position: number) {
-        let token = getTokenAtPosition(sourceFile, position);
+        const token = getTokenAtPosition(sourceFile, position);
 
         // First, we have to see if this position actually landed in a comment.
-        let commentRanges = getLeadingCommentRanges(sourceFile.text, token.pos);
+        const commentRanges = getLeadingCommentRanges(sourceFile.text, token.pos);
 
         return forEach(commentRanges, jsDocPrefix);
 
@@ -515,9 +515,9 @@ namespace ts {
         }
 
         if (node) {
-            let jsDocComment = node.jsDocComment;
+            const jsDocComment = node.jsDocComment;
             if (jsDocComment) {
-                for (let tag of jsDocComment.tags) {
+                for (const tag of jsDocComment.tags) {
                     if (tag.pos <= position && position <= tag.end) {
                         return tag;
                     }
@@ -535,8 +535,8 @@ namespace ts {
     }
 
     export function getNodeModifiers(node: Node): string {
-        let flags = getCombinedNodeFlags(node);
-        let result: string[] = [];
+        const flags = getCombinedNodeFlags(node);
+        const result: string[] = [];
 
         if (flags & NodeFlags.Private) result.push(ScriptElementKindModifier.privateMemberModifier);
         if (flags & NodeFlags.Protected) result.push(ScriptElementKindModifier.protectedMemberModifier);
@@ -608,7 +608,7 @@ namespace ts {
     }
 
     export function compareDataObjects(dst: any, src: any): boolean {
-        for (let e in dst) {
+        for (const e in dst) {
             if (typeof dst[e] === "object") {
                 if (!compareDataObjects(dst[e], src[e])) {
                     return false;
@@ -661,7 +661,7 @@ namespace ts {
         return symbol.declarations && symbol.declarations.length > 0 && symbol.declarations[0].kind === SyntaxKind.Parameter;
     }
 
-    let displayPartWriter = getDisplayPartWriter();
+    const displayPartWriter = getDisplayPartWriter();
     function getDisplayPartWriter(): DisplayPartsSymbolWriter {
         let displayParts: SymbolDisplayPart[];
         let lineStart: boolean;
@@ -687,7 +687,7 @@ namespace ts {
 
         function writeIndent() {
             if (lineStart) {
-                let indentString = getIndentString(indent);
+                const indentString = getIndentString(indent);
                 if (indentString) {
                     displayParts.push(displayPart(indentString, SymbolDisplayPartKind.space));
                 }
@@ -721,7 +721,7 @@ namespace ts {
         return displayPart(text, displayPartKind(symbol), symbol);
 
         function displayPartKind(symbol: Symbol): SymbolDisplayPartKind {
-            let flags = symbol.flags;
+            const flags = symbol.flags;
 
             if (flags & SymbolFlags.Variable) {
                 return isFirstDeclarationOfSymbolParameter(symbol) ? SymbolDisplayPartKind.parameterName : SymbolDisplayPartKind.localName;
@@ -792,7 +792,7 @@ namespace ts {
 
     export function mapToDisplayParts(writeDisplayParts: (writer: DisplayPartsSymbolWriter) => void): SymbolDisplayPart[] {
         writeDisplayParts(displayPartWriter);
-        let result = displayPartWriter.displayParts();
+        const result = displayPartWriter.displayParts();
         displayPartWriter.clear();
         return result;
     }
@@ -828,9 +828,9 @@ namespace ts {
 
         // Try to get the local symbol if we're dealing with an 'export default'
         // since that symbol has the "true" name.
-        let localExportDefaultSymbol = getLocalSymbolForExportDefault(symbol);
+        const localExportDefaultSymbol = getLocalSymbolForExportDefault(symbol);
 
-        let name = typeChecker.symbolToString(localExportDefaultSymbol || symbol);
+        const name = typeChecker.symbolToString(localExportDefaultSymbol || symbol);
 
         return name;
     }
@@ -847,7 +847,7 @@ namespace ts {
      * @return non-quoted string
      */
     export function stripQuotes(name: string) {
-        let length = name.length;
+        const length = name.length;
         if (length >= 2 &&
             name.charCodeAt(0) === name.charCodeAt(length - 1) &&
             (name.charCodeAt(0) === CharacterCodes.doubleQuote || name.charCodeAt(0) === CharacterCodes.singleQuote)) {

tests/baselines/reference/classAndInterfaceMergeConflictingMembers.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/conformance/classes/classDeclarations/classAndInterfaceMergeConflictingMembers.ts(10,15): error TS2686: All declarations of 'x' must have identical modifiers.
-tests/cases/conformance/classes/classDeclarations/classAndInterfaceMergeConflictingMembers.ts(14,5): error TS2686: All declarations of 'x' must have identical modifiers.
-tests/cases/conformance/classes/classDeclarations/classAndInterfaceMergeConflictingMembers.ts(18,13): error TS2686: All declarations of 'x' must have identical modifiers.
-tests/cases/conformance/classes/classDeclarations/classAndInterfaceMergeConflictingMembers.ts(22,5): error TS2686: All declarations of 'x' must have identical modifiers.
+tests/cases/conformance/classes/classDeclarations/classAndInterfaceMergeConflictingMembers.ts(10,15): error TS2687: All declarations of 'x' must have identical modifiers.
+tests/cases/conformance/classes/classDeclarations/classAndInterfaceMergeConflictingMembers.ts(14,5): error TS2687: All declarations of 'x' must have identical modifiers.
+tests/cases/conformance/classes/classDeclarations/classAndInterfaceMergeConflictingMembers.ts(18,13): error TS2687: All declarations of 'x' must have identical modifiers.
+tests/cases/conformance/classes/classDeclarations/classAndInterfaceMergeConflictingMembers.ts(22,5): error TS2687: All declarations of 'x' must have identical modifiers.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classAndInterfaceMergeConflictingMembers.ts (4 errors) ====
@@ -16,23 +16,23 @@ tests/cases/conformance/classes/classDeclarations/classAndInterfaceMergeConflict
     declare class C2 {
         protected x : number;
                   ~
-!!! error TS2686: All declarations of 'x' must have identical modifiers.
+!!! error TS2687: All declarations of 'x' must have identical modifiers.
     }
     
     interface C2 {
         x : number;
         ~
-!!! error TS2686: All declarations of 'x' must have identical modifiers.
+!!! error TS2687: All declarations of 'x' must have identical modifiers.
     }
     
     declare class C3 {
         private x : number;
                 ~
-!!! error TS2686: All declarations of 'x' must have identical modifiers.
+!!! error TS2687: All declarations of 'x' must have identical modifiers.
     }
     
     interface C3 {
         x : number;
         ~
-!!! error TS2686: All declarations of 'x' must have identical modifiers.
+!!! error TS2687: All declarations of 'x' must have identical modifiers.
     }

tests/baselines/reference/constructSignatureWithAccessibilityModifiersOnParameters2.errors.txt

@@ -1,8 +1,11 @@
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(4,17): error TS2369: A parameter property is only allowed in a constructor implementation.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(4,27): error TS2369: A parameter property is only allowed in a constructor implementation.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(5,24): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(5,35): error TS2300: Duplicate identifier 'y'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(9,17): error TS2369: A parameter property is only allowed in a constructor implementation.
-tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(9,25): error TS2686: All declarations of 'x' must have identical modifiers.
-tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(10,24): error TS2686: All declarations of 'x' must have identical modifiers.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(9,25): error TS2687: All declarations of 'x' must have identical modifiers.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(10,24): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(10,24): error TS2687: All declarations of 'x' must have identical modifiers.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(14,17): error TS2369: A parameter property is only allowed in a constructor implementation.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(19,10): error TS2369: A parameter property is only allowed in a constructor implementation.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(20,10): error TS2369: A parameter property is only allowed in a constructor implementation.
@@ -14,7 +17,7 @@ tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatur
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(35,10): error TS2369: A parameter property is only allowed in a constructor implementation.
 
 
-==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts (14 errors) ====
+==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts (17 errors) ====
     // Parameter properties are not valid in overloads of constructors
     
     class C {
@@ -24,6 +27,10 @@ tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatur
                               ~~~~~~~~~
 !!! error TS2369: A parameter property is only allowed in a constructor implementation.
         constructor(public x, private y) { }
+                           ~
+!!! error TS2300: Duplicate identifier 'x'.
+                                      ~
+!!! error TS2300: Duplicate identifier 'y'.
     }
     
     class C2 {
@@ -31,10 +38,12 @@ tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatur
                     ~~~~~~~~~
 !!! error TS2369: A parameter property is only allowed in a constructor implementation.
                             ~
-!!! error TS2686: All declarations of 'x' must have identical modifiers.
+!!! error TS2687: All declarations of 'x' must have identical modifiers.
         constructor(public x) { }
                            ~
-!!! error TS2686: All declarations of 'x' must have identical modifiers.
+!!! error TS2300: Duplicate identifier 'x'.
+                           ~
+!!! error TS2687: All declarations of 'x' must have identical modifiers.
     }
     
     class C3 {

tests/baselines/reference/constructorParameterProperties2.errors.txt

@@ -1,10 +1,10 @@
 tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(11,24): error TS2300: Duplicate identifier 'y'.
-tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(18,5): error TS2686: All declarations of 'y' must have identical modifiers.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(18,5): error TS2687: All declarations of 'y' must have identical modifiers.
 tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(19,25): error TS2300: Duplicate identifier 'y'.
-tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(19,25): error TS2686: All declarations of 'y' must have identical modifiers.
-tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(26,5): error TS2686: All declarations of 'y' must have identical modifiers.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(19,25): error TS2687: All declarations of 'y' must have identical modifiers.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(26,5): error TS2687: All declarations of 'y' must have identical modifiers.
 tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(27,27): error TS2300: Duplicate identifier 'y'.
-tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(27,27): error TS2686: All declarations of 'y' must have identical modifiers.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(27,27): error TS2687: All declarations of 'y' must have identical modifiers.
 
 
 ==== tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts (7 errors) ====
@@ -29,12 +29,12 @@ tests/cases/conformance/classes/constructorDeclarations/constructorParameters/co
     class E {
         y: number;
         ~
-!!! error TS2686: All declarations of 'y' must have identical modifiers.
+!!! error TS2687: All declarations of 'y' must have identical modifiers.
         constructor(private y: number) { } // error
                             ~
 !!! error TS2300: Duplicate identifier 'y'.
                             ~
-!!! error TS2686: All declarations of 'y' must have identical modifiers.
+!!! error TS2687: All declarations of 'y' must have identical modifiers.
     }
     
     var e: E;
@@ -43,12 +43,12 @@ tests/cases/conformance/classes/constructorDeclarations/constructorParameters/co
     class F {
         y: number;
         ~
-!!! error TS2686: All declarations of 'y' must have identical modifiers.
+!!! error TS2687: All declarations of 'y' must have identical modifiers.
         constructor(protected y: number) { } // error
                               ~
 !!! error TS2300: Duplicate identifier 'y'.
                               ~
-!!! error TS2686: All declarations of 'y' must have identical modifiers.
+!!! error TS2687: All declarations of 'y' must have identical modifiers.
     }
     
     var f: F;

tests/baselines/reference/duplicateIdentifierComputedName.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/duplicateIdentifierComputedName.ts(3,5): error TS2300: Duplicate identifier 'a'.
+tests/cases/compiler/duplicateIdentifierComputedName.ts(3,5): error TS2300: Duplicate identifier '["a"]'.
 
 
 ==== tests/cases/compiler/duplicateIdentifierComputedName.ts (1 errors) ====
@@ -6,6 +6,6 @@ tests/cases/compiler/duplicateIdentifierComputedName.ts(3,5): error TS2300: Dupl
         ["a"]: string;
         ["a"]: string;
         ~~~~~
-!!! error TS2300: Duplicate identifier 'a'.
+!!! error TS2300: Duplicate identifier '["a"]'.
     }
     

tests/baselines/reference/duplicateIdentifierDifferentModifiers.errors.txt

@@ -1,17 +1,17 @@
-tests/cases/compiler/duplicateIdentifierDifferentModifiers.ts(2,15): error TS2686: All declarations of 'x' must have identical modifiers.
-tests/cases/compiler/duplicateIdentifierDifferentModifiers.ts(3,15): error TS2686: All declarations of 'x' must have identical modifiers.
-tests/cases/compiler/duplicateIdentifierDifferentModifiers.ts(16,11): error TS2686: All declarations of 'y' must have identical modifiers.
-tests/cases/compiler/duplicateIdentifierDifferentModifiers.ts(20,3): error TS2686: All declarations of 'y' must have identical modifiers.
+tests/cases/compiler/duplicateIdentifierDifferentModifiers.ts(2,15): error TS2687: All declarations of 'x' must have identical modifiers.
+tests/cases/compiler/duplicateIdentifierDifferentModifiers.ts(3,15): error TS2687: All declarations of 'x' must have identical modifiers.
+tests/cases/compiler/duplicateIdentifierDifferentModifiers.ts(16,11): error TS2687: All declarations of 'y' must have identical modifiers.
+tests/cases/compiler/duplicateIdentifierDifferentModifiers.ts(20,3): error TS2687: All declarations of 'y' must have identical modifiers.
 
 
 ==== tests/cases/compiler/duplicateIdentifierDifferentModifiers.ts (4 errors) ====
     // Not OK
     interface B { x; }
                   ~
-!!! error TS2686: All declarations of 'x' must have identical modifiers.
+!!! error TS2687: All declarations of 'x' must have identical modifiers.
     interface B { x?; }
                   ~
-!!! error TS2686: All declarations of 'x' must have identical modifiers.
+!!! error TS2687: All declarations of 'x' must have identical modifiers.
     
     // OK
     class A {
@@ -26,12 +26,12 @@ tests/cases/compiler/duplicateIdentifierDifferentModifiers.ts(20,3): error TS268
     class C {
       private y: string;
               ~
-!!! error TS2686: All declarations of 'y' must have identical modifiers.
+!!! error TS2687: All declarations of 'y' must have identical modifiers.
     }
     
     interface C {
       y: string;
       ~
-!!! error TS2686: All declarations of 'y' must have identical modifiers.
+!!! error TS2687: All declarations of 'y' must have identical modifiers.
     }
     

tests/baselines/reference/intersectionTypeInference1.js

@@ -0,0 +1,17 @@
+//// [intersectionTypeInference1.ts]
+// Repro from #8801
+
+function alert(s: string) {}
+
+const parameterFn = (props:{store:string}) => alert(props.store)
+const brokenFunction = <OwnProps>(f: (p: {dispatch: number} & OwnProps) => void) => (o: OwnProps) => o
+export const Form3 = brokenFunction(parameterFn)({store: "hello"})
+
+
+//// [intersectionTypeInference1.js]
+// Repro from #8801
+"use strict";
+function alert(s) { }
+var parameterFn = function (props) { return alert(props.store); };
+var brokenFunction = function (f) { return function (o) { return o; }; };
+exports.Form3 = brokenFunction(parameterFn)({ store: "hello" });

tests/baselines/reference/intersectionTypeInference1.symbols

@@ -0,0 +1,33 @@
+=== tests/cases/compiler/intersectionTypeInference1.ts ===
+// Repro from #8801
+
+function alert(s: string) {}
+>alert : Symbol(alert, Decl(intersectionTypeInference1.ts, 0, 0))
+>s : Symbol(s, Decl(intersectionTypeInference1.ts, 2, 15))
+
+const parameterFn = (props:{store:string}) => alert(props.store)
+>parameterFn : Symbol(parameterFn, Decl(intersectionTypeInference1.ts, 4, 5))
+>props : Symbol(props, Decl(intersectionTypeInference1.ts, 4, 21))
+>store : Symbol(store, Decl(intersectionTypeInference1.ts, 4, 28))
+>alert : Symbol(alert, Decl(intersectionTypeInference1.ts, 0, 0))
+>props.store : Symbol(store, Decl(intersectionTypeInference1.ts, 4, 28))
+>props : Symbol(props, Decl(intersectionTypeInference1.ts, 4, 21))
+>store : Symbol(store, Decl(intersectionTypeInference1.ts, 4, 28))
+
+const brokenFunction = <OwnProps>(f: (p: {dispatch: number} & OwnProps) => void) => (o: OwnProps) => o
+>brokenFunction : Symbol(brokenFunction, Decl(intersectionTypeInference1.ts, 5, 5))
+>OwnProps : Symbol(OwnProps, Decl(intersectionTypeInference1.ts, 5, 24))
+>f : Symbol(f, Decl(intersectionTypeInference1.ts, 5, 34))
+>p : Symbol(p, Decl(intersectionTypeInference1.ts, 5, 38))
+>dispatch : Symbol(dispatch, Decl(intersectionTypeInference1.ts, 5, 42))
+>OwnProps : Symbol(OwnProps, Decl(intersectionTypeInference1.ts, 5, 24))
+>o : Symbol(o, Decl(intersectionTypeInference1.ts, 5, 85))
+>OwnProps : Symbol(OwnProps, Decl(intersectionTypeInference1.ts, 5, 24))
+>o : Symbol(o, Decl(intersectionTypeInference1.ts, 5, 85))
+
+export const Form3 = brokenFunction(parameterFn)({store: "hello"})
+>Form3 : Symbol(Form3, Decl(intersectionTypeInference1.ts, 6, 12))
+>brokenFunction : Symbol(brokenFunction, Decl(intersectionTypeInference1.ts, 5, 5))
+>parameterFn : Symbol(parameterFn, Decl(intersectionTypeInference1.ts, 4, 5))
+>store : Symbol(store, Decl(intersectionTypeInference1.ts, 6, 50))
+

tests/baselines/reference/intersectionTypeInference1.types

@@ -0,0 +1,41 @@
+=== tests/cases/compiler/intersectionTypeInference1.ts ===
+// Repro from #8801
+
+function alert(s: string) {}
+>alert : (s: string) => void
+>s : string
+
+const parameterFn = (props:{store:string}) => alert(props.store)
+>parameterFn : (props: { store: string; }) => void
+>(props:{store:string}) => alert(props.store) : (props: { store: string; }) => void
+>props : { store: string; }
+>store : string
+>alert(props.store) : void
+>alert : (s: string) => void
+>props.store : string
+>props : { store: string; }
+>store : string
+
+const brokenFunction = <OwnProps>(f: (p: {dispatch: number} & OwnProps) => void) => (o: OwnProps) => o
+>brokenFunction : <OwnProps>(f: (p: { dispatch: number; } & OwnProps) => void) => (o: OwnProps) => OwnProps
+><OwnProps>(f: (p: {dispatch: number} & OwnProps) => void) => (o: OwnProps) => o : <OwnProps>(f: (p: { dispatch: number; } & OwnProps) => void) => (o: OwnProps) => OwnProps
+>OwnProps : OwnProps
+>f : (p: { dispatch: number; } & OwnProps) => void
+>p : { dispatch: number; } & OwnProps
+>dispatch : number
+>OwnProps : OwnProps
+>(o: OwnProps) => o : (o: OwnProps) => OwnProps
+>o : OwnProps
+>OwnProps : OwnProps
+>o : OwnProps
+
+export const Form3 = brokenFunction(parameterFn)({store: "hello"})
+>Form3 : { store: string; }
+>brokenFunction(parameterFn)({store: "hello"}) : { store: string; }
+>brokenFunction(parameterFn) : (o: { store: string; }) => { store: string; }
+>brokenFunction : <OwnProps>(f: (p: { dispatch: number; } & OwnProps) => void) => (o: OwnProps) => OwnProps
+>parameterFn : (props: { store: string; }) => void
+>{store: "hello"} : { store: string; }
+>store : string
+>"hello" : string
+

tests/baselines/reference/numericClassMembers1.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/compiler/numericClassMembers1.ts(3,3): error TS2300: Duplicate identifier '0'.
-tests/cases/compiler/numericClassMembers1.ts(8,2): error TS2300: Duplicate identifier '0'.
+tests/cases/compiler/numericClassMembers1.ts(3,3): error TS2300: Duplicate identifier '0.0'.
+tests/cases/compiler/numericClassMembers1.ts(8,2): error TS2300: Duplicate identifier ''0''.
 
 
 ==== tests/cases/compiler/numericClassMembers1.ts (2 errors) ====
@@ -7,14 +7,14 @@ tests/cases/compiler/numericClassMembers1.ts(8,2): error TS2300: Duplicate ident
       0 = 1; 
       0.0 = 2;
       ~~~
-!!! error TS2300: Duplicate identifier '0'.
+!!! error TS2300: Duplicate identifier '0.0'.
     }
      
     class C235 { 
       0.0 = 1;
      '0' = 2;
      ~~~
-!!! error TS2300: Duplicate identifier '0'.
+!!! error TS2300: Duplicate identifier ''0''.
     }
     
     class C236 {

tests/baselines/reference/numericNamedPropertyDuplicates.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(3,5): error TS2300: Duplicate identifier '1'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(3,5): error TS2300: Duplicate identifier '1.0'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(5,12): error TS2300: Duplicate identifier '2'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(9,5): error TS2300: Duplicate identifier '2'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(10,5): error TS2300: Duplicate identifier '2'.
@@ -12,7 +12,7 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedP
         1: number;
         1.0: number;
         ~~~
-!!! error TS2300: Duplicate identifier '1'.
+!!! error TS2300: Duplicate identifier '1.0'.
         static 2: number;
         static 2: number;
                ~

tests/baselines/reference/numericStringNamedPropertyEquivalence.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(6,5): error TS2300: Duplicate identifier '1'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(6,5): error TS2300: Duplicate identifier '1.0'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(10,5): error TS2300: Duplicate identifier '1'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(12,5): error TS2300: Duplicate identifier '1'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(16,5): error TS2300: Duplicate identifier '1'.
@@ -15,7 +15,7 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericString
         "1.0": number; // not a duplicate
         1.0: number;
         ~~~
-!!! error TS2300: Duplicate identifier '1'.
+!!! error TS2300: Duplicate identifier '1.0'.
     }
     
     interface I {

tests/baselines/reference/objectTypeWithDuplicateNumericProperty.errors.txt

@@ -1,6 +1,6 @@
-tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(6,5): error TS2300: Duplicate identifier '1'.
-tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(7,5): error TS2300: Duplicate identifier '1'.
-tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(8,5): error TS2300: Duplicate identifier '1'.
+tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(6,5): error TS2300: Duplicate identifier '1.0'.
+tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(7,5): error TS2300: Duplicate identifier '1.'.
+tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(8,5): error TS2300: Duplicate identifier '1.00'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(12,5): error TS2300: Duplicate identifier '1'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(13,5): error TS2300: Duplicate identifier '1'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(14,5): error TS2300: Duplicate identifier '1'.
@@ -22,13 +22,13 @@ tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(
         1;
         1.0;
         ~~~
-!!! error TS2300: Duplicate identifier '1'.
+!!! error TS2300: Duplicate identifier '1.0'.
         1.;
         ~~
-!!! error TS2300: Duplicate identifier '1'.
+!!! error TS2300: Duplicate identifier '1.'.
         1.00;
         ~~~~
-!!! error TS2300: Duplicate identifier '1'.
+!!! error TS2300: Duplicate identifier '1.00'.
     }
     
     interface I {

tests/baselines/reference/optionalPropertiesSyntax.errors.txt

@@ -5,9 +5,9 @@ tests/cases/compiler/optionalPropertiesSyntax.ts(12,5): error TS1131: Property o
 tests/cases/compiler/optionalPropertiesSyntax.ts(18,11): error TS1005: ';' expected.
 tests/cases/compiler/optionalPropertiesSyntax.ts(18,12): error TS1131: Property or signature expected.
 tests/cases/compiler/optionalPropertiesSyntax.ts(24,5): error TS2300: Duplicate identifier 'prop'.
-tests/cases/compiler/optionalPropertiesSyntax.ts(24,5): error TS2686: All declarations of 'prop' must have identical modifiers.
+tests/cases/compiler/optionalPropertiesSyntax.ts(24,5): error TS2687: All declarations of 'prop' must have identical modifiers.
 tests/cases/compiler/optionalPropertiesSyntax.ts(25,5): error TS2300: Duplicate identifier 'prop'.
-tests/cases/compiler/optionalPropertiesSyntax.ts(25,5): error TS2686: All declarations of 'prop' must have identical modifiers.
+tests/cases/compiler/optionalPropertiesSyntax.ts(25,5): error TS2687: All declarations of 'prop' must have identical modifiers.
 tests/cases/compiler/optionalPropertiesSyntax.ts(32,5): error TS2375: Duplicate number index signature.
 tests/cases/compiler/optionalPropertiesSyntax.ts(32,18): error TS1005: ';' expected.
 tests/cases/compiler/optionalPropertiesSyntax.ts(32,19): error TS1131: Property or signature expected.
@@ -56,12 +56,12 @@ tests/cases/compiler/optionalPropertiesSyntax.ts(34,5): error TS2375: Duplicate
         ~~~~
 !!! error TS2300: Duplicate identifier 'prop'.
         ~~~~
-!!! error TS2686: All declarations of 'prop' must have identical modifiers.
+!!! error TS2687: All declarations of 'prop' must have identical modifiers.
         prop?: any;
         ~~~~
 !!! error TS2300: Duplicate identifier 'prop'.
         ~~~~
-!!! error TS2686: All declarations of 'prop' must have identical modifiers.
+!!! error TS2687: All declarations of 'prop' must have identical modifiers.
         prop2?: any;
     }
     

tests/baselines/reference/parameterPropertyInConstructor2.errors.txt

@@ -1,8 +1,9 @@
 tests/cases/compiler/parameterPropertyInConstructor2.ts(3,5): error TS2394: Overload signature is not compatible with function implementation.
 tests/cases/compiler/parameterPropertyInConstructor2.ts(3,17): error TS2369: A parameter property is only allowed in a constructor implementation.
+tests/cases/compiler/parameterPropertyInConstructor2.ts(4,24): error TS2300: Duplicate identifier 'names'.
 
 
-==== tests/cases/compiler/parameterPropertyInConstructor2.ts (2 errors) ====
+==== tests/cases/compiler/parameterPropertyInConstructor2.ts (3 errors) ====
     module mod {
       class Customers {
         constructor(public names: string);
@@ -11,6 +12,8 @@ tests/cases/compiler/parameterPropertyInConstructor2.ts(3,17): error TS2369: A p
                     ~~~~~~~~~~~~~~~~~~~~
 !!! error TS2369: A parameter property is only allowed in a constructor implementation.
         constructor(public names: string, public ages: number) {
+                           ~~~~~
+!!! error TS2300: Duplicate identifier 'names'.
         }
       }
     }

tests/baselines/reference/stringNamedPropertyDuplicates.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(3,5): error TS2300: Duplicate identifier 'a b'.
-tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(5,12): error TS2300: Duplicate identifier 'c d'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(3,5): error TS2300: Duplicate identifier '"a b"'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(5,12): error TS2300: Duplicate identifier '"c d"'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(9,5): error TS2300: Duplicate identifier 'a b'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(10,5): error TS2300: Duplicate identifier 'a b'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(14,5): error TS2300: Duplicate identifier 'a b'.
@@ -12,11 +12,11 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPr
         "a b": number;
         "a b": number;
         ~~~~~
-!!! error TS2300: Duplicate identifier 'a b'.
+!!! error TS2300: Duplicate identifier '"a b"'.
         static "c d": number;
         static "c d": number;
                ~~~~~
-!!! error TS2300: Duplicate identifier 'c d'.
+!!! error TS2300: Duplicate identifier '"c d"'.
     }
     
     interface I {

tests/baselines/reference/symbolProperty44.errors.txt

@@ -1,9 +1,8 @@
 tests/cases/conformance/es6/Symbols/symbolProperty44.ts(2,9): error TS2300: Duplicate identifier '[Symbol.hasInstance]'.
 tests/cases/conformance/es6/Symbols/symbolProperty44.ts(5,9): error TS2300: Duplicate identifier '[Symbol.hasInstance]'.
-tests/cases/conformance/es6/Symbols/symbolProperty44.ts(5,9): error TS2300: Duplicate identifier '__@hasInstance'.
 
 
-==== tests/cases/conformance/es6/Symbols/symbolProperty44.ts (3 errors) ====
+==== tests/cases/conformance/es6/Symbols/symbolProperty44.ts (2 errors) ====
     class C {
         get [Symbol.hasInstance]() {
             ~~~~~~~~~~~~~~~~~~~~
@@ -13,8 +12,6 @@ tests/cases/conformance/es6/Symbols/symbolProperty44.ts(5,9): error TS2300: Dupl
         get [Symbol.hasInstance]() {
             ~~~~~~~~~~~~~~~~~~~~
 !!! error TS2300: Duplicate identifier '[Symbol.hasInstance]'.
-            ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2300: Duplicate identifier '__@hasInstance'.
             return "";
         }
     }

tests/cases/compiler/intersectionTypeInference1.ts

@@ -0,0 +1,7 @@
+// Repro from #8801
+
+function alert(s: string) {}
+
+const parameterFn = (props:{store:string}) => alert(props.store)
+const brokenFunction = <OwnProps>(f: (p: {dispatch: number} & OwnProps) => void) => (o: OwnProps) => o
+export const Form3 = brokenFunction(parameterFn)({store: "hello"})

tests/cases/fourslash/getNavigationBarItems.ts

@@ -5,7 +5,7 @@
 ////    ["bar"]: string;
 ////}
 
-verify.navigationBarCount(3);
+verify.navigationBarCount(5);
 verify.navigationBarContains("C", "class");
 verify.navigationBarChildItem("C", "[\"bar\"]", "property");
 verify.navigationBarChildItem("C", "foo", "property");

tests/cases/fourslash/navbar_contains-no-duplicates.ts

@@ -2,7 +2,7 @@
 //// {| "itemName": "Windows", "kind": "module", "parentName": "<global>" |}declare module Windows {
 ////     {| "itemName": "Foundation", "kind": "module", "parentName": "Windows" |}export module Foundation {
 ////         export var {| "itemName": "A", "kind": "var" |}A;
-////         {| "itemName": "Test", "kind": "class" |}export class Test {
+////         {| "itemName": "Test", "kind": "class", "parentName": "Foundation" |}export class Test {
 ////             {| "itemName": "wow", "kind": "method" |}public wow();
 ////         }
 ////     }
@@ -38,4 +38,5 @@ test.markers().forEach(marker => {
             marker.position);
     }
 });
-verify.navigationBarCount(17);
+
+verify.navigationBarCount(19);

tests/cases/fourslash/navigationBarItemsBindingPatternsInConstructor.ts

@@ -11,4 +11,4 @@
 ////    }
 ////}
 
-verify.navigationBarCount(6); // 2x(class + field + constructor)
+verify.navigationBarCount(9); // global + 2 children + 2x(class + field + constructor)

tests/cases/fourslash/navigationBarItemsEmptyConstructors.ts

@@ -9,4 +9,4 @@ verify.navigationBarContains("Test", "class");
 verify.navigationBarContains("constructor", "constructor");
 
 // no other items
-verify.navigationBarCount(2);
+verify.navigationBarCount(4); // global + 1 child, Test + 1 child

tests/cases/fourslash/navigationBarItemsInsideMethodsAndConstructors.ts

@@ -6,7 +6,7 @@
 ////
 ////        }
 ////
-////        {| "itemName": "LocalInterfaceInConstrcutor", "kind": "interface", "parentName": ""|}interface LocalInterfaceInConstrcutor {
+////        {| "itemName": "LocalInterfaceInConstrcutor", "kind": "interface", "parentName": "constructor"|}interface LocalInterfaceInConstrcutor {
 ////        }
 ////
 ////        {| "itemName": "LocalEnumInConstructor", "kind": "enum", "parentName": "constructor"|}enum LocalEnumInConstructor {
@@ -21,7 +21,7 @@
 ////            }
 ////        }
 ////
-////        {| "itemName": "LocalInterfaceInMethod", "kind": "interface", "parentName": ""|}interface LocalInterfaceInMethod {
+////        {| "itemName": "LocalInterfaceInMethod", "kind": "interface", "parentName": "method"|}interface LocalInterfaceInMethod {
 ////        }
 ////
 ////        {| "itemName": "LocalEnumInMethod", "kind": "enum", "parentName": "method"|}enum LocalEnumInMethod {
@@ -39,4 +39,4 @@ test.markers().forEach((marker) => {
 });
 
 // no other items
-verify.navigationBarCount(19);
+verify.navigationBarCount(23);

tests/cases/fourslash/navigationBarItemsItems.ts

@@ -1,7 +1,7 @@
 /// <reference path="fourslash.ts"/>
 
 ////// Interface
-////{| "itemName": "IPoint", "kind": "interface", "parentName": "" |}interface IPoint {
+////{| "itemName": "IPoint", "kind": "interface", "parentName": "<global>" |}interface IPoint {
 ////    {| "itemName": "getDist", "kind": "method", "parentName": "IPoint" |}getDist(): number;
 ////    {| "itemName": "new()", "kind": "construct", "parentName": "IPoint" |}new(): IPoint;
 ////    {| "itemName": "()", "kind": "call", "parentName": "IPoint" |}(): any;
@@ -13,7 +13,7 @@
 ////{| "itemName": "Shapes", "kind": "module", "parentName": "<global>" |}module Shapes {
 ////
 ////    // Class
-////    {| "itemName": "Point", "kind": "class", "parentName": "" |}export class Point implements IPoint {
+////    {| "itemName": "Point", "kind": "class", "parentName": "Shapes" |}export class Point implements IPoint {
 ////        {| "itemName": "constructor", "kind": "constructor", "parentName": "Point" |}constructor (public x: number, public y: number) { }
 ////
 ////        // Instance member
@@ -49,4 +49,4 @@ test.markers().forEach((marker) => {
     }
 });
 
-verify.navigationBarCount(25);
+verify.navigationBarCount(27);

tests/cases/fourslash/navigationBarItemsItemsExternalModules.ts

@@ -1,6 +1,6 @@
 /// <reference path="fourslash.ts"/>
 
-////{| "itemName": "Bar", "kind": "class" |}export class Bar {
+////{| "itemName": "Bar", "kind": "class", "parentName": "\"navigationBarItemsItemsExternalModules\"" |}export class Bar {
 ////    {| "itemName": "s", "kind": "property", "parentName": "Bar" |}public s: string;
 ////}
 
@@ -8,4 +8,4 @@ test.markers().forEach((marker) => {
     verify.navigationBarContains(marker.data.itemName, marker.data.kind, marker.fileName, marker.data.parentName);
 });
 
-verify.navigationBarCount(2); // external module node + class + property
+verify.navigationBarCount(4); // external module node + class + property

tests/cases/fourslash/navigationBarItemsItemsExternalModules2.ts

@@ -1,7 +1,7 @@
 /// <reference path="fourslash.ts"/>
 
 // @Filename: test/file.ts
-////{| "itemName": "Bar", "kind": "class" |}export class Bar {
+////{| "itemName": "Bar", "kind": "class", "parentName": "\"file\"" |}export class Bar {
 ////    {| "itemName": "s", "kind": "property", "parentName": "Bar" |}public s: string;
 ////}
 ////{| "itemName": "\"file\"", "kind": "module" |}
@@ -12,4 +12,4 @@ test.markers().forEach((marker) => {
     verify.navigationBarContains(marker.data.itemName, marker.data.kind, marker.fileName, marker.data.parentName);
 });
 
-verify.navigationBarCount(4); // external module node + variable in module + class + property
+verify.navigationBarCount(5); // external module node + variable in module + class + property

tests/cases/fourslash/navigationBarItemsItemsExternalModules3.ts

@@ -1,7 +1,7 @@
 /// <reference path="fourslash.ts"/>
 
 // @Filename: test/my fil"e.ts
-////{| "itemName": "Bar", "kind": "class" |}export class Bar {
+////{| "itemName": "Bar", "kind": "class", "parentName": "\"my fil\\\"e\"" |}export class Bar {
 ////    {| "itemName": "s", "kind": "property", "parentName": "Bar" |}public s: string;
 ////}
 ////{| "itemName": "\"my fil\\\"e\"", "kind": "module" |}
@@ -12,4 +12,4 @@ test.markers().forEach((marker) => {
     verify.navigationBarContains(marker.data.itemName, marker.data.kind, marker.fileName, marker.data.parentName);
 });
 
-verify.navigationBarCount(4); // external module node + variable in module + class + property
+verify.navigationBarCount(5); // external module node + 2 children + class + property

tests/cases/fourslash/navigationBarItemsMissingName1.ts

@@ -2,7 +2,7 @@
 /////**
 //// * This is a class.
 //// */
-////{| "itemName": "C", "kind": "class" |} class C {
+////{| "itemName": "C", "kind": "class", "parentName": "\"navigationBarItemsMissingName1\"" |} class C {
 ////    {| "itemName": "foo", "kind": "method" |} foo() {
 ////    }
 ////}
@@ -12,5 +12,5 @@ test.markers().forEach((marker) => {
     verify.navigationBarContains(marker.data.itemName, marker.data.kind, marker.fileName, marker.data.parentName);
 });
 
-/// Only have two named elements.
-verify.navigationBarCount(2);
+/// Root + 1 child, class + 1 child
+verify.navigationBarCount(4);

tests/cases/fourslash/navigationBarItemsMultilineStringIdentifiers.ts

@@ -10,7 +10,7 @@
 ////{| "itemName": "\"MultilineMadness\"", "kind": "module", "parentName": "<global>" |}
 ////declare module "MultilineMadness" {}
 ////
-////{| "itemName": "Foo", "kind": "interface" |}
+////{| "itemName": "Foo", "kind": "interface", "parentName": "<global>" |}
 ////interface Foo {
 ////    {| "itemName": "\"a1\\\\\\r\\nb\"", "kind": "property", "parentName": "Foo" |}
 ////    "a1\\\r\nb";
@@ -20,7 +20,7 @@
 ////    b"(): Foo;
 ////}
 ////
-////{| "itemName": "Bar", "kind": "class" |}
+////{| "itemName": "Bar", "kind": "class", "parentName": "<global>" |}
 ////class Bar implements Foo {
 ////    {| "itemName": "'a1\\\\\\r\\nb'", "kind": "property", "parentName": "Bar" |}
 ////    'a1\\\r\nb': Foo;
@@ -38,4 +38,4 @@ test.markers().forEach((marker) => {
     verify.navigationBarContains(marker.data.itemName, marker.data.kind, marker.fileName, marker.data.parentName);
 });
 
-verify.navigationBarCount(13);
+verify.navigationBarCount(15);

tests/cases/fourslash/navigationBarItemsPropertiesDefinedInConstructors.ts

@@ -12,4 +12,4 @@ verify.navigationBarContains("a", "property");
 verify.navigationBarContains("b", "property");
 
 // no other items
-verify.navigationBarCount(4);
+verify.navigationBarCount(6);

tests/cases/fourslash/navigationBarItemsSymbols1.ts

@@ -1,6 +1,6 @@
 /// <reference path="fourslash.ts"/>
 
-////{| "itemName": "C", "kind": "class", "parentName": "" |}
+////{| "itemName": "C", "kind": "class", "parentName": "<global>" |}
 ////class C {
 ////    {| "itemName": "[Symbol.isRegExp]", "kind": "property", "parentName": "C" |}
 ////    [Symbol.isRegExp] = 0;
@@ -14,4 +14,5 @@ test.markers().forEach(marker => {
     verify.navigationBarContains(marker.data.itemName, marker.data.kind, marker.fileName, marker.data.parentName);
 });
 
-verify.navigationBarCount(test.markers().length);
+// 2 lack markers: <global> and its child
+verify.navigationBarCount(2 + test.markers().length);

tests/cases/fourslash/navigationBarItemsSymbols2.ts

@@ -1,6 +1,6 @@
 /// <reference path="fourslash.ts"/>
 
-////{| "itemName": "I", "kind": "interface", "parentName": "" |}
+////{| "itemName": "I", "kind": "interface", "parentName": "<global>" |}
 ////interface I {
 ////    {| "itemName": "[Symbol.isRegExp]", "kind": "property", "parentName": "I" |}
 ////    [Symbol.isRegExp]: string;
@@ -12,4 +12,5 @@ test.markers().forEach(marker => {
     verify.navigationBarContains(marker.data.itemName, marker.data.kind, marker.fileName, marker.data.parentName);
 });
 
-verify.navigationBarCount(test.markers().length);
+// 2 are not marked: <global> and its child.
+verify.navigationBarCount(2 + test.markers().length);

tests/cases/fourslash/server/navbar01.ts

@@ -1,7 +1,7 @@
 /// <reference path="../fourslash.ts"/>
 
 ////// Interface
-////{| "itemName": "IPoint", "kind": "interface", "parentName": "" |}interface IPoint {
+////{| "itemName": "IPoint", "kind": "interface", "parentName": "<global>" |}interface IPoint {
 ////    {| "itemName": "getDist", "kind": "method", "parentName": "IPoint" |}getDist(): number;
 ////    {| "itemName": "new()", "kind": "construct", "parentName": "IPoint" |}new(): IPoint;
 ////    {| "itemName": "()", "kind": "call", "parentName": "IPoint" |}(): any;
@@ -13,7 +13,7 @@
 ////{| "itemName": "Shapes", "kind": "module", "parentName": "<global>" |}module Shapes {
 ////
 ////    // Class
-////    {| "itemName": "Point", "kind": "class", "parentName": "" |}export class Point implements IPoint {
+////    {| "itemName": "Point", "kind": "class", "parentName": "Shapes" |}export class Point implements IPoint {
 ////        {| "itemName": "constructor", "kind": "constructor", "parentName": "Point" |}constructor (public x: number, public y: number) { }
 ////
 ////        // Instance member
@@ -49,4 +49,4 @@ test.markers().forEach((marker) => {
     }
 });
 
-verify.navigationBarCount(25);
+verify.navigationBarCount(27);