diff --git a/lib/tsc.js b/lib/tsc.js
index 94ec709879f..f42b484993c 100644
--- a/lib/tsc.js
+++ b/lib/tsc.js
@@ -132,7 +132,7 @@ var ts;
 })(ts || (ts = {}));
 var ts;
 (function (ts) {
-    ts.version = "2.1.3";
+    ts.version = "2.1.4";
 })(ts || (ts = {}));
 (function (ts) {
     var createObject = Object.create;
@@ -2668,6 +2668,7 @@ var ts;
         Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword: { code: 2340, category: ts.DiagnosticCategory.Error, key: "Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword_2340", message: "Only public and protected methods of the base class are accessible via the 'super' keyword." },
         Property_0_is_private_and_only_accessible_within_class_1: { code: 2341, category: ts.DiagnosticCategory.Error, key: "Property_0_is_private_and_only_accessible_within_class_1_2341", message: "Property '{0}' is private and only accessible within class '{1}'." },
         An_index_expression_argument_must_be_of_type_string_number_symbol_or_any: { code: 2342, category: ts.DiagnosticCategory.Error, key: "An_index_expression_argument_must_be_of_type_string_number_symbol_or_any_2342", message: "An index expression argument must be of type 'string', 'number', 'symbol', or 'any'." },
+        This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1: { code: 2343, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1_2343", message: "This syntax requires an imported helper named '{1}', but module '{0}' has no exported member '{1}'." },
         Type_0_does_not_satisfy_the_constraint_1: { code: 2344, category: ts.DiagnosticCategory.Error, key: "Type_0_does_not_satisfy_the_constraint_1_2344", message: "Type '{0}' does not satisfy the constraint '{1}'." },
         Argument_of_type_0_is_not_assignable_to_parameter_of_type_1: { code: 2345, category: ts.DiagnosticCategory.Error, key: "Argument_of_type_0_is_not_assignable_to_parameter_of_type_1_2345", message: "Argument of type '{0}' is not assignable to parameter of type '{1}'." },
         Supplied_parameters_do_not_match_any_signature_of_call_target: { code: 2346, category: ts.DiagnosticCategory.Error, key: "Supplied_parameters_do_not_match_any_signature_of_call_target_2346", message: "Supplied parameters do not match any signature of call target." },
@@ -2678,6 +2679,7 @@ var ts;
         Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature: { code: 2351, category: ts.DiagnosticCategory.Error, key: "Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature_2351", message: "Cannot use 'new' with an expression whose type lacks a call or construct signature." },
         Type_0_cannot_be_converted_to_type_1: { code: 2352, category: ts.DiagnosticCategory.Error, key: "Type_0_cannot_be_converted_to_type_1_2352", message: "Type '{0}' cannot be converted to type '{1}'." },
         Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1: { code: 2353, category: ts.DiagnosticCategory.Error, key: "Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1_2353", message: "Object literal may only specify known properties, and '{0}' does not exist in type '{1}'." },
+        This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found: { code: 2354, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found_2354", message: "This syntax requires an imported helper but module '{0}' cannot be found." },
         A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value: { code: 2355, category: ts.DiagnosticCategory.Error, key: "A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value_2355", message: "A function whose declared type is neither 'void' nor 'any' must return a value." },
         An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type: { code: 2356, category: ts.DiagnosticCategory.Error, key: "An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type_2356", message: "An arithmetic operand must be of type 'any', 'number' or an enum type." },
         The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access: { code: 2357, category: ts.DiagnosticCategory.Error, key: "The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access_2357", message: "The operand of an increment or decrement operator must be a variable or a property access." },
@@ -2984,6 +2986,8 @@ var ts;
         Default_export_of_the_module_has_or_is_using_private_name_0: { code: 4082, category: ts.DiagnosticCategory.Error, key: "Default_export_of_the_module_has_or_is_using_private_name_0_4082", message: "Default export of the module has or is using private name '{0}'." },
         Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1: { code: 4083, category: ts.DiagnosticCategory.Error, key: "Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1_4083", message: "Type parameter '{0}' of exported type alias has or is using private name '{1}'." },
         Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_library_to_resolve_the_conflict: { code: 4090, category: ts.DiagnosticCategory.Message, key: "Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_librar_4090", message: "Conflicting definitions for '{0}' found at '{1}' and '{2}'. Consider installing a specific version of this library to resolve the conflict." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2: { code: 4091, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2_4091", message: "Parameter '{0}' of index signature from exported interface has or is using name '{1}' from private module '{2}'." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1: { code: 4092, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1_4092", message: "Parameter '{0}' of index signature from exported interface has or is using private name '{1}'." },
         The_current_host_does_not_support_the_0_option: { code: 5001, category: ts.DiagnosticCategory.Error, key: "The_current_host_does_not_support_the_0_option_5001", message: "The current host does not support the '{0}' option." },
         Cannot_find_the_common_subdirectory_path_for_the_input_files: { code: 5009, category: ts.DiagnosticCategory.Error, key: "Cannot_find_the_common_subdirectory_path_for_the_input_files_5009", message: "Cannot find the common subdirectory path for the input files." },
         File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0: { code: 5010, category: ts.DiagnosticCategory.Error, key: "File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0_5010", message: "File specification cannot end in a recursive directory wildcard ('**'): '{0}'." },
@@ -4869,17 +4873,17 @@ var ts;
     ts.hasChangesInResolutions = hasChangesInResolutions;
     function containsParseError(node) {
         aggregateChildData(node);
-        return (node.flags & 4194304) !== 0;
+        return (node.flags & 131072) !== 0;
     }
     ts.containsParseError = containsParseError;
     function aggregateChildData(node) {
-        if (!(node.flags & 8388608)) {
-            var thisNodeOrAnySubNodesHasError = ((node.flags & 1048576) !== 0) ||
+        if (!(node.flags & 262144)) {
+            var thisNodeOrAnySubNodesHasError = ((node.flags & 32768) !== 0) ||
                 ts.forEachChild(node, containsParseError);
             if (thisNodeOrAnySubNodesHasError) {
-                node.flags |= 4194304;
+                node.flags |= 131072;
             }
-            node.flags |= 8388608;
+            node.flags |= 262144;
         }
     }
     function getSourceFileOfNode(node) {
@@ -5103,6 +5107,10 @@ var ts;
         return false;
     }
     ts.isExternalModuleAugmentation = isExternalModuleAugmentation;
+    function isEffectiveExternalModule(node, compilerOptions) {
+        return ts.isExternalModule(node) || compilerOptions.isolatedModules;
+    }
+    ts.isEffectiveExternalModule = isEffectiveExternalModule;
     function isBlockScope(node, parentNode) {
         switch (node.kind) {
             case 261:
@@ -5858,7 +5866,7 @@ var ts;
     }
     ts.isSourceFileJavaScript = isSourceFileJavaScript;
     function isInJavaScriptFile(node) {
-        return node && !!(node.flags & 2097152);
+        return node && !!(node.flags & 65536);
     }
     ts.isInJavaScriptFile = isInJavaScriptFile;
     function isRequireCall(expression, checkArgumentIsStringLiteral) {
@@ -6097,7 +6105,7 @@ var ts;
     }
     ts.hasDeclaredRestParameter = hasDeclaredRestParameter;
     function isRestParameter(node) {
-        if (node && (node.flags & 2097152)) {
+        if (node && (node.flags & 65536)) {
             if (node.type && node.type.kind === 275 ||
                 ts.forEach(getJSDocParameterTags(node), function (t) { return t.typeExpression && t.typeExpression.type.kind === 275; })) {
                 return true;
@@ -11636,7 +11644,7 @@ var ts;
     var Parser;
     (function (Parser) {
         var scanner = ts.createScanner(5, true);
-        var disallowInAndDecoratorContext = 65536 | 262144;
+        var disallowInAndDecoratorContext = 2048 | 8192;
         var NodeConstructor;
         var TokenConstructor;
         var IdentifierConstructor;
@@ -11684,7 +11692,7 @@ var ts;
             identifiers = ts.createMap();
             identifierCount = 0;
             nodeCount = 0;
-            contextFlags = scriptKind === 1 || scriptKind === 2 ? 2097152 : 0;
+            contextFlags = scriptKind === 1 || scriptKind === 2 ? 65536 : 0;
             parseErrorBeforeNextFinishedNode = false;
             scanner.setText(sourceText);
             scanner.setOnError(scanError);
@@ -11779,16 +11787,16 @@ var ts;
             }
         }
         function setDisallowInContext(val) {
-            setContextFlag(val, 65536);
+            setContextFlag(val, 2048);
         }
         function setYieldContext(val) {
-            setContextFlag(val, 131072);
+            setContextFlag(val, 4096);
         }
         function setDecoratorContext(val) {
-            setContextFlag(val, 262144);
+            setContextFlag(val, 8192);
         }
         function setAwaitContext(val) {
-            setContextFlag(val, 524288);
+            setContextFlag(val, 16384);
         }
         function doOutsideOfContext(context, func) {
             var contextFlagsToClear = context & contextFlags;
@@ -11811,40 +11819,40 @@ var ts;
             return func();
         }
         function allowInAnd(func) {
-            return doOutsideOfContext(65536, func);
+            return doOutsideOfContext(2048, func);
         }
         function disallowInAnd(func) {
-            return doInsideOfContext(65536, func);
+            return doInsideOfContext(2048, func);
         }
         function doInYieldContext(func) {
-            return doInsideOfContext(131072, func);
+            return doInsideOfContext(4096, func);
         }
         function doInDecoratorContext(func) {
-            return doInsideOfContext(262144, func);
+            return doInsideOfContext(8192, func);
         }
         function doInAwaitContext(func) {
-            return doInsideOfContext(524288, func);
+            return doInsideOfContext(16384, func);
         }
         function doOutsideOfAwaitContext(func) {
-            return doOutsideOfContext(524288, func);
+            return doOutsideOfContext(16384, func);
         }
         function doInYieldAndAwaitContext(func) {
-            return doInsideOfContext(131072 | 524288, func);
+            return doInsideOfContext(4096 | 16384, func);
         }
         function inContext(flags) {
             return (contextFlags & flags) !== 0;
         }
         function inYieldContext() {
-            return inContext(131072);
+            return inContext(4096);
         }
         function inDisallowInContext() {
-            return inContext(65536);
+            return inContext(2048);
         }
         function inDecoratorContext() {
-            return inContext(262144);
+            return inContext(8192);
         }
         function inAwaitContext() {
-            return inContext(524288);
+            return inContext(16384);
         }
         function parseErrorAtCurrentToken(message, arg0) {
             var start = scanner.getTokenPos();
@@ -12006,7 +12014,7 @@ var ts;
             }
             if (parseErrorBeforeNextFinishedNode) {
                 parseErrorBeforeNextFinishedNode = false;
-                node.flags |= 1048576;
+                node.flags |= 32768;
             }
             return node;
         }
@@ -12324,7 +12332,7 @@ var ts;
             if (ts.containsParseError(node)) {
                 return undefined;
             }
-            var nodeContextFlags = node.flags & 3080192;
+            var nodeContextFlags = node.flags & 96256;
             if (nodeContextFlags !== contextFlags) {
                 return undefined;
             }
@@ -13132,7 +13140,7 @@ var ts;
             }
         }
         function parseType() {
-            return doOutsideOfContext(655360, parseTypeWorker);
+            return doOutsideOfContext(20480, parseTypeWorker);
         }
         function parseTypeWorker() {
             if (isStartOfFunctionType()) {
@@ -14763,7 +14771,7 @@ var ts;
             property.type = parseTypeAnnotation();
             property.initializer = ts.hasModifier(property, 32)
                 ? allowInAnd(parseNonParameterInitializer)
-                : doOutsideOfContext(131072 | 65536, parseNonParameterInitializer);
+                : doOutsideOfContext(4096 | 2048, parseNonParameterInitializer);
             parseSemicolon();
             return addJSDocComment(finishNode(property));
         }
@@ -16737,7 +16745,7 @@ var ts;
                 activeLabels = undefined;
                 hasExplicitReturn = false;
                 bindChildren(node);
-                node.flags &= ~64896;
+                node.flags &= ~1408;
                 if (!(currentFlow.flags & 1) && containerFlags & 8 && ts.nodeIsPresent(node.body)) {
                     node.flags |= 128;
                     if (hasExplicitReturn)
@@ -17920,9 +17928,6 @@ var ts;
                     return bindParameter(node);
                 case 223:
                 case 174:
-                    if (node.dotDotDotToken && node.parent.kind === 172) {
-                        emitFlags |= 32768;
-                    }
                     return bindVariableDeclarationOrBindingElement(node);
                 case 147:
                 case 146:
@@ -17949,7 +17954,6 @@ var ts;
                         }
                         root = root.parent;
                     }
-                    emitFlags |= hasRest ? 32768 : 16384;
                     return;
                 case 153:
                 case 154:
@@ -18145,14 +18149,6 @@ var ts;
             }
         }
         function bindClassLikeDeclaration(node) {
-            if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
-                if (ts.getClassExtendsHeritageClauseElement(node) !== undefined) {
-                    emitFlags |= 1024;
-                }
-                if (ts.nodeIsDecorated(node)) {
-                    emitFlags |= 2048;
-                }
-            }
             if (node.kind === 226) {
                 bindBlockScopedDeclaration(node, 32, 899519);
             }
@@ -18196,11 +18192,6 @@ var ts;
             }
         }
         function bindParameter(node) {
-            if (!ts.isDeclarationFile(file) &&
-                !ts.isInAmbientContext(node) &&
-                ts.nodeIsDecorated(node)) {
-                emitFlags |= (2048 | 4096);
-            }
             if (inStrictMode) {
                 checkStrictModeEvalOrArguments(node, node.name);
             }
@@ -18218,7 +18209,7 @@ var ts;
         function bindFunctionDeclaration(node) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192;
+                    emitFlags |= 1024;
                 }
             }
             checkStrictModeFunctionName(node);
@@ -18233,7 +18224,7 @@ var ts;
         function bindFunctionExpression(node) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192;
+                    emitFlags |= 1024;
                 }
             }
             if (currentFlow) {
@@ -18246,10 +18237,7 @@ var ts;
         function bindPropertyOrMethodOrAccessor(node, symbolFlags, symbolExcludes) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192;
-                }
-                if (ts.nodeIsDecorated(node)) {
-                    emitFlags |= 2048;
+                    emitFlags |= 1024;
                 }
             }
             if (currentFlow && ts.isObjectLiteralOrClassExpressionMethod(node)) {
@@ -19539,6 +19527,8 @@ var ts;
     ts.getSymbolId = getSymbolId;
     function createTypeChecker(host, produceDiagnostics) {
         var cancellationToken;
+        var requestedExternalEmitHelpers;
+        var externalHelpersModule;
         var Symbol = ts.objectAllocator.getSymbolConstructor();
         var Type = ts.objectAllocator.getTypeConstructor();
         var Signature = ts.objectAllocator.getSignatureConstructor();
@@ -21867,7 +21857,13 @@ var ts;
             return name.kind === 142 && !ts.isStringOrNumericLiteral(name.expression);
         }
         function getRestType(source, properties, symbol) {
-            ts.Debug.assert(!!(source.flags & 32768), "Rest types only support object types right now.");
+            source = filterType(source, function (t) { return !(t.flags & 6144); });
+            if (source.flags & 8192) {
+                return emptyObjectType;
+            }
+            if (source.flags & 65536) {
+                return mapType(source, function (t) { return getRestType(t, properties, symbol); });
+            }
             var members = ts.createMap();
             var names = ts.createMap();
             for (var _i = 0, properties_2 = properties; _i < properties_2.length; _i++) {
@@ -21903,7 +21899,7 @@ var ts;
             var type;
             if (pattern.kind === 172) {
                 if (declaration.dotDotDotToken) {
-                    if (!(parentType.flags & 32768)) {
+                    if (!isValidSpreadType(parentType)) {
                         error(declaration, ts.Diagnostics.Rest_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
@@ -21981,7 +21977,7 @@ var ts;
             return strictNullChecks && optional ? includeFalsyTypes(type, 2048) : type;
         }
         function getTypeForVariableLikeDeclaration(declaration, includeOptionality) {
-            if (declaration.flags & 2097152) {
+            if (declaration.flags & 65536) {
                 var type = getTypeForVariableLikeDeclarationFromJSDocComment(declaration);
                 if (type && type !== unknownType) {
                     return type;
@@ -22000,7 +21996,7 @@ var ts;
             if (declaration.type) {
                 return addOptionality(getTypeFromTypeNode(declaration.type), declaration.questionToken && includeOptionality);
             }
-            if ((compilerOptions.noImplicitAny || declaration.flags & 2097152) &&
+            if ((compilerOptions.noImplicitAny || declaration.flags & 65536) &&
                 declaration.kind === 223 && !ts.isBindingPattern(declaration.name) &&
                 !(ts.getCombinedModifierFlags(declaration) & 1) && !ts.isInAmbientContext(declaration)) {
                 if (!(ts.getCombinedNodeFlags(declaration) & 2) && (!declaration.initializer || isNullOrUndefined(declaration.initializer))) {
@@ -22061,13 +22057,18 @@ var ts;
         }
         function getTypeFromObjectBindingPattern(pattern, includePatternInType, reportErrors) {
             var members = ts.createMap();
+            var stringIndexInfo;
             var hasComputedProperties = false;
             ts.forEach(pattern.elements, function (e) {
                 var name = e.propertyName || e.name;
-                if (isComputedNonLiteralName(name) || e.dotDotDotToken) {
+                if (isComputedNonLiteralName(name)) {
                     hasComputedProperties = true;
                     return;
                 }
+                if (e.dotDotDotToken) {
+                    stringIndexInfo = createIndexInfo(anyType, false);
+                    return;
+                }
                 var text = ts.getTextOfPropertyName(name);
                 var flags = 4 | 67108864 | (e.initializer ? 536870912 : 0);
                 var symbol = createSymbol(flags, text);
@@ -22075,7 +22076,7 @@ var ts;
                 symbol.bindingElement = e;
                 members[symbol.name] = symbol;
             });
-            var result = createAnonymousType(undefined, members, emptyArray, emptyArray, undefined, undefined);
+            var result = createAnonymousType(undefined, members, emptyArray, emptyArray, stringIndexInfo, undefined);
             if (includePatternInType) {
                 result.pattern = pattern;
             }
@@ -22140,7 +22141,7 @@ var ts;
                 if (declaration.kind === 240) {
                     return links.type = checkExpression(declaration.expression);
                 }
-                if (declaration.flags & 2097152 && declaration.kind === 286 && declaration.typeExpression) {
+                if (declaration.flags & 65536 && declaration.kind === 286 && declaration.typeExpression) {
                     return links.type = getTypeFromTypeNode(declaration.typeExpression.type);
                 }
                 if (!pushTypeResolution(symbol, 0)) {
@@ -22149,7 +22150,7 @@ var ts;
                 var type = void 0;
                 if (declaration.kind === 192 ||
                     declaration.kind === 177 && declaration.parent.kind === 192) {
-                    if (declaration.flags & 2097152) {
+                    if (declaration.flags & 65536) {
                         var jsdocType = ts.getJSDocType(declaration.parent);
                         if (jsdocType) {
                             return links.type = getTypeFromTypeNode(jsdocType);
@@ -22203,7 +22204,7 @@ var ts;
             if (!links.type) {
                 var getter = ts.getDeclarationOfKind(symbol, 151);
                 var setter = ts.getDeclarationOfKind(symbol, 152);
-                if (getter && getter.flags & 2097152) {
+                if (getter && getter.flags & 65536) {
                     var jsDocType = getTypeForVariableLikeDeclarationFromJSDocComment(getter);
                     if (jsDocType) {
                         return links.type = jsDocType;
@@ -23074,7 +23075,7 @@ var ts;
                     var isomorphicProp = isomorphicType && getPropertyOfType(isomorphicType, propName);
                     var isOptional = templateOptional || !!(isomorphicProp && isomorphicProp.flags & 536870912);
                     var prop = createSymbol(4 | 67108864 | (isOptional ? 536870912 : 0), propName);
-                    prop.type = addOptionality(propType, isOptional);
+                    prop.type = propType;
                     prop.isReadonly = templateReadonly || isomorphicProp && isReadonlySymbol(isomorphicProp);
                     members[propName] = prop;
                 }
@@ -23095,7 +23096,7 @@ var ts;
         function getTemplateTypeFromMappedType(type) {
             return type.templateType ||
                 (type.templateType = type.declaration.type ?
-                    instantiateType(getTypeFromTypeNode(type.declaration.type), type.mapper || identityMapper) :
+                    instantiateType(addOptionality(getTypeFromTypeNode(type.declaration.type), !!type.declaration.questionToken), type.mapper || identityMapper) :
                     unknownType);
         }
         function getIsomorphicTypeFromMappedType(type) {
@@ -23344,7 +23345,7 @@ var ts;
             return undefined;
         }
         function getTypeParametersFromJSDocTemplate(declaration) {
-            if (declaration.flags & 2097152) {
+            if (declaration.flags & 65536) {
                 var templateTag = ts.getJSDocTemplateTag(declaration);
                 if (templateTag) {
                     return getTypeParametersFromDeclaration(templateTag.typeParameters);
@@ -23372,7 +23373,7 @@ var ts;
             return result;
         }
         function isJSDocOptionalParameter(node) {
-            if (node.flags & 2097152) {
+            if (node.flags & 65536) {
                 if (node.type && node.type.kind === 273) {
                     return true;
                 }
@@ -23501,7 +23502,7 @@ var ts;
             else if (declaration.type) {
                 return getTypeFromTypeNode(declaration.type);
             }
-            if (declaration.flags & 2097152) {
+            if (declaration.flags & 65536) {
                 var type = getReturnTypeFromJSDocComment(declaration);
                 if (type && type !== unknownType) {
                     return type;
@@ -24308,7 +24309,7 @@ var ts;
             }
             var mapper = createUnaryTypeMapper(getTypeParameterFromMappedType(type), indexType);
             var templateMapper = type.mapper ? combineTypeMappers(type.mapper, mapper) : mapper;
-            return addOptionality(instantiateType(getTemplateTypeFromMappedType(type), templateMapper), !!type.declaration.questionToken);
+            return instantiateType(getTemplateTypeFromMappedType(type), templateMapper);
         }
         function getIndexedAccessType(objectType, indexType, accessNode) {
             if (indexType.flags & 16384 ||
@@ -24384,10 +24385,23 @@ var ts;
             return symbol ? getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol) : undefined;
         }
         function getSpreadType(left, right, isFromObjectLiteral) {
-            ts.Debug.assert(!!(left.flags & (32768 | 1)) && !!(right.flags & (32768 | 1)), "Only object types may be spread.");
             if (left.flags & 1 || right.flags & 1) {
                 return anyType;
             }
+            left = filterType(left, function (t) { return !(t.flags & 6144); });
+            if (left.flags & 8192) {
+                return right;
+            }
+            right = filterType(right, function (t) { return !(t.flags & 6144); });
+            if (right.flags & 8192) {
+                return left;
+            }
+            if (left.flags & 65536) {
+                return mapType(left, function (t) { return getSpreadType(t, right, isFromObjectLiteral); });
+            }
+            if (right.flags & 65536) {
+                return mapType(right, function (t) { return getSpreadType(left, t, isFromObjectLiteral); });
+            }
             var members = ts.createMap();
             var skippedPrivateMembers = ts.createMap();
             var stringIndexInfo;
@@ -26312,6 +26326,8 @@ var ts;
             var typeInferences = createTypeInferencesObject();
             var typeInferencesArray = [typeInferences];
             var templateType = getTemplateTypeFromMappedType(target);
+            var readonlyMask = target.declaration.readonlyToken ? false : true;
+            var optionalMask = target.declaration.questionToken ? 0 : 536870912;
             var properties = getPropertiesOfType(source);
             var members = createSymbolTable(properties);
             var hasInferredTypes = false;
@@ -26319,10 +26335,10 @@ var ts;
                 var prop = properties_4[_i];
                 var inferredPropType = inferTargetType(getTypeOfSymbol(prop));
                 if (inferredPropType) {
-                    var inferredProp = createSymbol(4 | 67108864 | prop.flags & 536870912, prop.name);
+                    var inferredProp = createSymbol(4 | 67108864 | prop.flags & optionalMask, prop.name);
                     inferredProp.declarations = prop.declarations;
                     inferredProp.type = inferredPropType;
-                    inferredProp.isReadonly = isReadonlySymbol(prop);
+                    inferredProp.isReadonly = readonlyMask && isReadonlySymbol(prop);
                     members[prop.name] = inferredProp;
                     hasInferredTypes = true;
                 }
@@ -26331,7 +26347,7 @@ var ts;
             if (indexInfo) {
                 var inferredIndexType = inferTargetType(indexInfo.type);
                 if (inferredIndexType) {
-                    indexInfo = createIndexInfo(inferredIndexType, indexInfo.isReadonly);
+                    indexInfo = createIndexInfo(inferredIndexType, readonlyMask && indexInfo.isReadonly);
                     hasInferredTypes = true;
                 }
             }
@@ -27668,7 +27684,7 @@ var ts;
                         error(node, ts.Diagnostics.The_arguments_object_cannot_be_referenced_in_an_async_function_or_method_in_ES3_and_ES5_Consider_using_a_standard_function_or_method);
                     }
                 }
-                if (node.flags & 524288) {
+                if (node.flags & 16384) {
                     getNodeLinks(container).flags |= 8192;
                 }
                 return getTypeOfSymbol(symbol);
@@ -28581,7 +28597,7 @@ var ts;
                         if (impliedProp) {
                             prop.flags |= impliedProp.flags & 536870912;
                         }
-                        else if (!compilerOptions.suppressExcessPropertyErrors) {
+                        else if (!compilerOptions.suppressExcessPropertyErrors && !getIndexInfoOfType(contextualType, 0)) {
                             error(memberDecl.name, ts.Diagnostics.Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1, symbolToString(member), typeToString(contextualType));
                         }
                     }
@@ -28595,6 +28611,9 @@ var ts;
                     member = prop;
                 }
                 else if (memberDecl.kind === 259) {
+                    if (languageVersion < 5) {
+                        checkExternalEmitHelpers(memberDecl, 2);
+                    }
                     if (propertiesArray.length > 0) {
                         spread = getSpreadType(spread, createObjectLiteralType(), true);
                         propertiesArray = [];
@@ -28604,7 +28623,7 @@ var ts;
                         typeFlags = 0;
                     }
                     var type = checkExpression(memberDecl.expression);
-                    if (!(type.flags & (32768 | 1))) {
+                    if (!isValidSpreadType(type)) {
                         error(memberDecl, ts.Diagnostics.Spread_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
@@ -28669,6 +28688,11 @@ var ts;
                 return result;
             }
         }
+        function isValidSpreadType(type) {
+            return !!(type.flags & (1 | 4096 | 2048) ||
+                type.flags & 32768 && !isGenericMappedType(type) ||
+                type.flags & 196608 && !ts.forEach(type.types, function (t) { return !isValidSpreadType(t); }));
+        }
         function checkJsxSelfClosingElement(node) {
             checkJsxOpeningLikeElement(node);
             return jsxElementType || anyType;
@@ -28743,6 +28767,9 @@ var ts;
             return exprType;
         }
         function checkJsxSpreadAttribute(node, elementAttributesType, nameTable) {
+            if (compilerOptions.jsx === 2) {
+                checkExternalEmitHelpers(node, 2);
+            }
             var type = checkExpression(node.expression);
             var props = getPropertiesOfType(type);
             for (var _i = 0, props_2 = props; _i < props_2.length; _i++) {
@@ -30489,7 +30516,7 @@ var ts;
         }
         function checkAwaitExpression(node) {
             if (produceDiagnostics) {
-                if (!(node.flags & 524288)) {
+                if (!(node.flags & 16384)) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.await_expression_is_only_allowed_within_an_async_function);
                 }
                 if (isInParameterInitializerBeforeContainingFunction(node)) {
@@ -30647,6 +30674,9 @@ var ts;
                 }
             }
             else if (property.kind === 259) {
+                if (languageVersion < 5) {
+                    checkExternalEmitHelpers(property, 4);
+                }
                 var nonRestNames = [];
                 if (allProperties) {
                     for (var i = 0; i < allProperties.length - 1; i++) {
@@ -30997,7 +31027,7 @@ var ts;
         }
         function checkYieldExpression(node) {
             if (produceDiagnostics) {
-                if (!(node.flags & 131072) || isYieldExpressionInClass(node)) {
+                if (!(node.flags & 4096) || isYieldExpressionInClass(node)) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.A_yield_expression_is_only_allowed_in_a_generator_body);
                 }
                 if (isInParameterInitializerBeforeContainingFunction(node)) {
@@ -31373,6 +31403,12 @@ var ts;
                 node.kind === 154) {
                 checkGrammarFunctionLikeDeclaration(node);
             }
+            if (ts.isAsyncFunctionLike(node) && languageVersion < 4) {
+                checkExternalEmitHelpers(node, 64);
+                if (languageVersion < 2) {
+                    checkExternalEmitHelpers(node, 128);
+                }
+            }
             checkTypeParameters(node.typeParameters);
             ts.forEach(node.parameters, checkParameter);
             if (node.type) {
@@ -32167,7 +32203,13 @@ var ts;
             if (!compilerOptions.experimentalDecorators) {
                 error(node, ts.Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning);
             }
+            var firstDecorator = node.decorators[0];
+            checkExternalEmitHelpers(firstDecorator, 8);
+            if (node.kind === 144) {
+                checkExternalEmitHelpers(firstDecorator, 32);
+            }
             if (compilerOptions.emitDecoratorMetadata) {
+                checkExternalEmitHelpers(firstDecorator, 16);
                 switch (node.kind) {
                     case 226:
                         var constructor = ts.getFirstConstructorWithBody(node);
@@ -32484,14 +32526,14 @@ var ts;
             }
         }
         function checkCollisionWithGlobalPromiseInGeneratedCode(node, name) {
-            if (!needCollisionCheckForIdentifier(node, name, "Promise")) {
+            if (languageVersion >= 4 || !needCollisionCheckForIdentifier(node, name, "Promise")) {
                 return;
             }
             if (node.kind === 230 && ts.getModuleInstanceState(node) !== 1) {
                 return;
             }
             var parent = getDeclarationContainer(node);
-            if (parent.kind === 261 && ts.isExternalOrCommonJsModule(parent) && parent.flags & 8192) {
+            if (parent.kind === 261 && ts.isExternalOrCommonJsModule(parent) && parent.flags & 1024) {
                 error(name, ts.Diagnostics.Duplicate_identifier_0_Compiler_reserves_name_1_in_top_level_scope_of_a_module_containing_async_functions, ts.declarationNameToString(name), ts.declarationNameToString(name));
             }
         }
@@ -32588,6 +32630,9 @@ var ts;
                 }
             }
             if (node.kind === 174) {
+                if (node.parent.kind === 172 && languageVersion < 5) {
+                    checkExternalEmitHelpers(node, 4);
+                }
                 if (node.propertyName && node.propertyName.kind === 142) {
                     checkComputedPropertyName(node.propertyName);
                 }
@@ -32997,7 +33042,7 @@ var ts;
         }
         function checkWithStatement(node) {
             if (!checkGrammarStatementInAmbientContext(node)) {
-                if (node.flags & 524288) {
+                if (node.flags & 16384) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.with_statements_are_not_allowed_in_an_async_function_block);
                 }
             }
@@ -33243,6 +33288,9 @@ var ts;
             checkClassForDuplicateDeclarations(node);
             var baseTypeNode = ts.getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
+                if (languageVersion < 2) {
+                    checkExternalEmitHelpers(baseTypeNode.parent, 1);
+                }
                 var baseTypes = getBaseTypes(type);
                 if (baseTypes.length && produceDiagnostics) {
                     var baseType_1 = baseTypes[0];
@@ -35150,8 +35198,6 @@ var ts;
                 ts.bindSourceFile(file, compilerOptions);
             }
             var augmentations;
-            var requestedExternalEmitHelpers = 0;
-            var firstFileRequestingExternalHelpers;
             for (var _b = 0, _c = host.getSourceFiles(); _b < _c.length; _b++) {
                 var file = _c[_b];
                 if (!ts.isExternalOrCommonJsModule(file)) {
@@ -35171,15 +35217,6 @@ var ts;
                         }
                     }
                 }
-                if ((compilerOptions.isolatedModules || ts.isExternalModule(file)) && !file.isDeclarationFile) {
-                    var fileRequestedExternalEmitHelpers = file.flags & 64512;
-                    if (fileRequestedExternalEmitHelpers) {
-                        requestedExternalEmitHelpers |= fileRequestedExternalEmitHelpers;
-                        if (firstFileRequestingExternalHelpers === undefined) {
-                            firstFileRequestingExternalHelpers = file;
-                        }
-                    }
-                }
             }
             if (augmentations) {
                 for (var _d = 0, augmentations_1 = augmentations; _d < augmentations_1.length; _d++) {
@@ -35234,44 +35271,46 @@ var ts;
             var symbol = getGlobalSymbol("ReadonlyArray", 793064, undefined);
             globalReadonlyArrayType = symbol && getTypeOfGlobalSymbol(symbol, 1);
             anyReadonlyArrayType = globalReadonlyArrayType ? createTypeFromGenericGlobalType(globalReadonlyArrayType, [anyType]) : anyArrayType;
-            if (compilerOptions.importHelpers && firstFileRequestingExternalHelpers) {
-                var helpersModule = resolveExternalModule(firstFileRequestingExternalHelpers, ts.externalHelpersModuleNameText, ts.Diagnostics.Cannot_find_module_0, undefined);
-                if (helpersModule) {
-                    var exports = helpersModule.exports;
-                    if (requestedExternalEmitHelpers & 1024 && languageVersion < 2) {
-                        verifyHelperSymbol(exports, "__extends", 107455);
-                    }
-                    if (requestedExternalEmitHelpers & 16384 &&
-                        (languageVersion < 5 || compilerOptions.jsx === 2)) {
-                        verifyHelperSymbol(exports, "__assign", 107455);
-                    }
-                    if (languageVersion < 5 && requestedExternalEmitHelpers & 32768) {
-                        verifyHelperSymbol(exports, "__rest", 107455);
-                    }
-                    if (requestedExternalEmitHelpers & 2048) {
-                        verifyHelperSymbol(exports, "__decorate", 107455);
-                        if (compilerOptions.emitDecoratorMetadata) {
-                            verifyHelperSymbol(exports, "__metadata", 107455);
-                        }
-                    }
-                    if (requestedExternalEmitHelpers & 4096) {
-                        verifyHelperSymbol(exports, "__param", 107455);
-                    }
-                    if (requestedExternalEmitHelpers & 8192) {
-                        verifyHelperSymbol(exports, "__awaiter", 107455);
-                        if (languageVersion < 2) {
-                            verifyHelperSymbol(exports, "__generator", 107455);
+        }
+        function checkExternalEmitHelpers(location, helpers) {
+            if ((requestedExternalEmitHelpers & helpers) !== helpers && compilerOptions.importHelpers) {
+                var sourceFile = ts.getSourceFileOfNode(location);
+                if (ts.isEffectiveExternalModule(sourceFile, compilerOptions)) {
+                    var helpersModule = resolveHelpersModule(sourceFile, location);
+                    if (helpersModule !== unknownSymbol) {
+                        var uncheckedHelpers = helpers & ~requestedExternalEmitHelpers;
+                        for (var helper = 1; helper <= 128; helper <<= 1) {
+                            if (uncheckedHelpers & helper) {
+                                var name_27 = getHelperName(helper);
+                                var symbol = getSymbol(helpersModule.exports, ts.escapeIdentifier(name_27), 107455);
+                                if (!symbol) {
+                                    error(location, ts.Diagnostics.This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1, ts.externalHelpersModuleNameText, name_27);
+                                }
+                            }
                         }
                     }
+                    requestedExternalEmitHelpers |= helpers;
                 }
             }
         }
-        function verifyHelperSymbol(symbols, name, meaning) {
-            var symbol = getSymbol(symbols, ts.escapeIdentifier(name), meaning);
-            if (!symbol) {
-                error(undefined, ts.Diagnostics.Module_0_has_no_exported_member_1, ts.externalHelpersModuleNameText, name);
+        function getHelperName(helper) {
+            switch (helper) {
+                case 1: return "__extends";
+                case 2: return "__assign";
+                case 4: return "__rest";
+                case 8: return "__decorate";
+                case 16: return "__metadata";
+                case 32: return "__param";
+                case 64: return "__awaiter";
+                case 128: return "__generator";
             }
         }
+        function resolveHelpersModule(node, errorNode) {
+            if (!externalHelpersModule) {
+                externalHelpersModule = resolveExternalModule(node, ts.externalHelpersModuleNameText, ts.Diagnostics.This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found, errorNode) || unknownSymbol;
+            }
+            return externalHelpersModule;
+        }
         function createInstantiatedPromiseLikeType() {
             var promiseLikeType = getGlobalPromiseLikeType();
             if (promiseLikeType !== emptyGenericType) {
@@ -35794,9 +35833,9 @@ var ts;
                 if (prop.kind === 259) {
                     continue;
                 }
-                var name_27 = prop.name;
-                if (name_27.kind === 142) {
-                    checkGrammarComputedPropertyName(name_27);
+                var name_28 = prop.name;
+                if (name_28.kind === 142) {
+                    checkGrammarComputedPropertyName(name_28);
                 }
                 if (prop.kind === 258 && !inDestructuring && prop.objectAssignmentInitializer) {
                     return grammarErrorOnNode(prop.equalsToken, ts.Diagnostics.can_only_be_used_in_an_object_literal_property_inside_a_destructuring_assignment);
@@ -35812,8 +35851,8 @@ var ts;
                 var currentKind = void 0;
                 if (prop.kind === 257 || prop.kind === 258) {
                     checkGrammarForInvalidQuestionMark(prop.questionToken, ts.Diagnostics.An_object_member_cannot_be_declared_optional);
-                    if (name_27.kind === 8) {
-                        checkGrammarNumericLiteral(name_27);
+                    if (name_28.kind === 8) {
+                        checkGrammarNumericLiteral(name_28);
                     }
                     currentKind = Property;
                 }
@@ -35829,7 +35868,7 @@ var ts;
                 else {
                     ts.Debug.fail("Unexpected syntax kind:" + prop.kind);
                 }
-                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_27);
+                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_28);
                 if (effectiveName === undefined) {
                     continue;
                 }
@@ -35839,18 +35878,18 @@ var ts;
                 else {
                     var existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
-                        grammarErrorOnNode(name_27, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_27));
+                        grammarErrorOnNode(name_28, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_28));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
                             seen[effectiveName] = currentKind | existingKind;
                         }
                         else {
-                            return grammarErrorOnNode(name_27, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
+                            return grammarErrorOnNode(name_28, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
                         }
                     }
                     else {
-                        return grammarErrorOnNode(name_27, ts.Diagnostics.An_object_literal_cannot_have_property_and_accessor_with_the_same_name);
+                        return grammarErrorOnNode(name_28, ts.Diagnostics.An_object_literal_cannot_have_property_and_accessor_with_the_same_name);
                     }
                 }
             }
@@ -35863,12 +35902,12 @@ var ts;
                     continue;
                 }
                 var jsxAttr = attr;
-                var name_28 = jsxAttr.name;
-                if (!seen[name_28.text]) {
-                    seen[name_28.text] = true;
+                var name_29 = jsxAttr.name;
+                if (!seen[name_29.text]) {
+                    seen[name_29.text] = true;
                 }
                 else {
-                    return grammarErrorOnNode(name_28, ts.Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
+                    return grammarErrorOnNode(name_29, ts.Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
                 }
                 var initializer = jsxAttr.initializer;
                 if (initializer && initializer.kind === 252 && !initializer.expression) {
@@ -37186,10 +37225,10 @@ var ts;
             }
         }
         for (var _i = 0, pendingDeclarations_1 = pendingDeclarations; _i < pendingDeclarations_1.length; _i++) {
-            var _a = pendingDeclarations_1[_i], pendingExpressions_1 = _a.pendingExpressions, name_29 = _a.name, value = _a.value, location_2 = _a.location, original = _a.original;
-            var variable = ts.createVariableDeclaration(name_29, undefined, pendingExpressions_1 ? ts.inlineExpressions(ts.append(pendingExpressions_1, value)) : value, location_2);
+            var _a = pendingDeclarations_1[_i], pendingExpressions_1 = _a.pendingExpressions, name_30 = _a.name, value = _a.value, location_2 = _a.location, original = _a.original;
+            var variable = ts.createVariableDeclaration(name_30, undefined, pendingExpressions_1 ? ts.inlineExpressions(ts.append(pendingExpressions_1, value)) : value, location_2);
             variable.original = original;
-            if (ts.isIdentifier(name_29)) {
+            if (ts.isIdentifier(name_30)) {
                 ts.setEmitFlags(variable, 64);
             }
             ts.aggregateTransformFlags(variable);
@@ -37335,8 +37374,8 @@ var ts;
             return ts.createElementAccess(value, argumentExpression);
         }
         else {
-            var name_30 = ts.createIdentifier(ts.unescapeIdentifier(propertyName.text));
-            return ts.createPropertyAccess(value, name_30);
+            var name_31 = ts.createIdentifier(ts.unescapeIdentifier(propertyName.text));
+            return ts.createPropertyAccess(value, name_31);
         }
     }
     function ensureIdentifier(flattenContext, value, reuseIdentifierExpressions, location) {
@@ -37378,7 +37417,7 @@ var ts;
     var restHelper = {
         name: "typescript:rest",
         scoped: false,
-        text: "\n            var __rest = (this && this.__rest) || function (s, e) {\n                var t = {};\n                for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)\n                    t[p] = s[p];\n                if (typeof Object.getOwnPropertySymbols === \"function\")\n                    for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)\n                        t[p[i]] = s[p[i]];\n                return t;\n            };"
+        text: "\n            var __rest = (this && this.__rest) || function (s, e) {\n                var t = {};\n                for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)\n                    t[p] = s[p];\n                if (s != null && typeof Object.getOwnPropertySymbols === \"function\")\n                    for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)\n                        t[p[i]] = s[p[i]];\n                return t;\n            };"
     };
     function createRestCall(context, value, elements, computedTempVariables, location) {
         context.requestEmitHelper(restHelper);
@@ -38248,14 +38287,14 @@ var ts;
         function serializeEntityNameAsExpression(node, useFallback) {
             switch (node.kind) {
                 case 70:
-                    var name_31 = ts.getMutableClone(node);
-                    name_31.flags &= ~8;
-                    name_31.original = undefined;
-                    name_31.parent = currentScope;
+                    var name_32 = ts.getMutableClone(node);
+                    name_32.flags &= ~8;
+                    name_32.original = undefined;
+                    name_32.parent = currentScope;
                     if (useFallback) {
-                        return ts.createLogicalAnd(ts.createStrictInequality(ts.createTypeOf(name_31), ts.createLiteral("undefined")), name_31);
+                        return ts.createLogicalAnd(ts.createStrictInequality(ts.createTypeOf(name_32), ts.createLiteral("undefined")), name_32);
                     }
-                    return name_31;
+                    return name_32;
                 case 141:
                     return serializeQualifiedNameAsExpression(node, useFallback);
             }
@@ -38285,7 +38324,7 @@ var ts;
                     : name.expression;
             }
             else if (ts.isIdentifier(name)) {
-                return ts.createLiteral(name.text);
+                return ts.createLiteral(ts.unescapeIdentifier(name.text));
             }
             else {
                 return ts.getSynthesizedClone(name);
@@ -38526,9 +38565,9 @@ var ts;
         }
         function isFirstEmittedDeclarationInScope(node) {
             if (currentScopeFirstDeclarationsOfName) {
-                var name_32 = node.symbol && node.symbol.name;
-                if (name_32) {
-                    return currentScopeFirstDeclarationsOfName[name_32] === node;
+                var name_33 = node.symbol && node.symbol.name;
+                if (name_33) {
+                    return currentScopeFirstDeclarationsOfName[name_33] === node;
                 }
             }
             return false;
@@ -38817,14 +38856,14 @@ var ts;
         }
         function substituteShorthandPropertyAssignment(node) {
             if (enabledSubstitutions & 2) {
-                var name_33 = node.name;
-                var exportedName = trySubstituteNamespaceExportedName(name_33);
+                var name_34 = node.name;
+                var exportedName = trySubstituteNamespaceExportedName(name_34);
                 if (exportedName) {
                     if (node.objectAssignmentInitializer) {
                         var initializer = ts.createAssignment(exportedName, node.objectAssignmentInitializer);
-                        return ts.createPropertyAssignment(name_33, initializer, node);
+                        return ts.createPropertyAssignment(name_34, initializer, node);
                     }
-                    return ts.createPropertyAssignment(name_33, exportedName, node);
+                    return ts.createPropertyAssignment(name_34, exportedName, node);
                 }
             }
             return node;
@@ -39345,12 +39384,12 @@ var ts;
                 return getTagName(node.openingElement);
             }
             else {
-                var name_34 = node.tagName;
-                if (ts.isIdentifier(name_34) && ts.isIntrinsicJsxName(name_34.text)) {
-                    return ts.createLiteral(name_34.text);
+                var name_35 = node.tagName;
+                if (ts.isIdentifier(name_35) && ts.isIntrinsicJsxName(name_35.text)) {
+                    return ts.createLiteral(name_35.text);
                 }
                 else {
-                    return ts.createExpressionFromEntityName(name_34);
+                    return ts.createExpressionFromEntityName(name_35);
                 }
             }
         }
@@ -40483,15 +40522,15 @@ var ts;
             }
             for (var _i = 0, _a = node.parameters; _i < _a.length; _i++) {
                 var parameter = _a[_i];
-                var name_35 = parameter.name, initializer = parameter.initializer, dotDotDotToken = parameter.dotDotDotToken;
+                var name_36 = parameter.name, initializer = parameter.initializer, dotDotDotToken = parameter.dotDotDotToken;
                 if (dotDotDotToken) {
                     continue;
                 }
-                if (ts.isBindingPattern(name_35)) {
-                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name_35, initializer);
+                if (ts.isBindingPattern(name_36)) {
+                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name_36, initializer);
                 }
                 else if (initializer) {
-                    addDefaultValueAssignmentForInitializer(statements, parameter, name_35, initializer);
+                    addDefaultValueAssignmentForInitializer(statements, parameter, name_36, initializer);
                 }
             }
         }
@@ -42496,9 +42535,9 @@ var ts;
                 if (ts.isIdentifier(original) && original.parent) {
                     var declaration = resolver.getReferencedValueDeclaration(original);
                     if (declaration) {
-                        var name_36 = ts.getProperty(renamedCatchVariableDeclarations, String(ts.getOriginalNodeId(declaration)));
-                        if (name_36) {
-                            var clone_6 = ts.getMutableClone(name_36);
+                        var name_37 = ts.getProperty(renamedCatchVariableDeclarations, String(ts.getOriginalNodeId(declaration)));
+                        if (name_37) {
+                            var clone_6 = ts.getMutableClone(name_37);
                             ts.setSourceMapRange(clone_6, node);
                             ts.setCommentRange(clone_6, node);
                             return clone_6;
@@ -44667,8 +44706,8 @@ var ts;
                         return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent), ts.createIdentifier("default"), node);
                     }
                     else if (ts.isImportSpecifier(importDeclaration)) {
-                        var name_37 = importDeclaration.propertyName || importDeclaration.name;
-                        return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent.parent.parent), ts.getSynthesizedClone(name_37), node);
+                        var name_38 = importDeclaration.propertyName || importDeclaration.name;
+                        return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent.parent.parent), ts.getSynthesizedClone(name_38), node);
                     }
                 }
             }
@@ -45925,9 +45964,9 @@ var ts;
             var count = 0;
             while (true) {
                 count++;
-                var name_38 = baseName + "_" + count;
-                if (!(name_38 in currentIdentifiers)) {
-                    return name_38;
+                var name_39 = baseName + "_" + count;
+                if (!(name_39 in currentIdentifiers)) {
+                    return name_39;
                 }
             }
         }
@@ -46816,6 +46855,10 @@ var ts;
                         return symbolAccessibilityResult.errorModuleName ?
                             ts.Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
                             ts.Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_private_name_1;
+                    case 155:
+                        return symbolAccessibilityResult.errorModuleName ?
+                            ts.Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
+                            ts.Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1;
                     case 149:
                     case 148:
                         if (ts.hasModifier(node.parent, 32)) {
@@ -48890,21 +48933,21 @@ var ts;
         }
         function makeTempVariableName(flags) {
             if (flags && !(tempFlags & flags)) {
-                var name_39 = flags === 268435456 ? "_i" : "_n";
-                if (isUniqueName(name_39)) {
+                var name_40 = flags === 268435456 ? "_i" : "_n";
+                if (isUniqueName(name_40)) {
                     tempFlags |= flags;
-                    return name_39;
+                    return name_40;
                 }
             }
             while (true) {
                 var count = tempFlags & 268435455;
                 tempFlags++;
                 if (count !== 8 && count !== 13) {
-                    var name_40 = count < 26
+                    var name_41 = count < 26
                         ? "_" + String.fromCharCode(97 + count)
                         : "_" + (count - 26);
-                    if (isUniqueName(name_40)) {
-                        return name_40;
+                    if (isUniqueName(name_41)) {
+                        return name_41;
                     }
                 }
             }
@@ -49240,10 +49283,10 @@ var ts;
         var resolutions = [];
         var cache = ts.createMap();
         for (var _i = 0, names_1 = names; _i < names_1.length; _i++) {
-            var name_41 = names_1[_i];
-            var result = name_41 in cache
-                ? cache[name_41]
-                : cache[name_41] = loader(name_41, containingFile);
+            var name_42 = names_1[_i];
+            var result = name_42 in cache
+                ? cache[name_42]
+                : cache[name_42] = loader(name_42, containingFile);
             resolutions.push(result);
         }
         return resolutions;
@@ -51057,9 +51100,9 @@ var ts;
         function serializeCompilerOptions(options) {
             var result = ts.createMap();
             var optionsNameMap = getOptionNameMap().optionNameMap;
-            for (var name_42 in options) {
-                if (ts.hasProperty(options, name_42)) {
-                    switch (name_42) {
+            for (var name_43 in options) {
+                if (ts.hasProperty(options, name_43)) {
+                    switch (name_43) {
                         case "init":
                         case "watch":
                         case "version":
@@ -51067,12 +51110,12 @@ var ts;
                         case "project":
                             break;
                         default:
-                            var value = options[name_42];
-                            var optionDefinition = optionsNameMap[name_42.toLowerCase()];
+                            var value = options[name_43];
+                            var optionDefinition = optionsNameMap[name_43.toLowerCase()];
                             if (optionDefinition) {
                                 var customTypeMap = getCustomTypeMapOfCommandLineOption(optionDefinition);
                                 if (!customTypeMap) {
-                                    result[name_42] = value;
+                                    result[name_43] = value;
                                 }
                                 else {
                                     if (optionDefinition.type === "list") {
@@ -51081,10 +51124,10 @@ var ts;
                                             var element = _a[_i];
                                             convertedValue.push(getNameOfCompilerOptionValue(element, customTypeMap));
                                         }
-                                        result[name_42] = convertedValue;
+                                        result[name_43] = convertedValue;
                                     }
                                     else {
-                                        result[name_42] = getNameOfCompilerOptionValue(value, customTypeMap);
+                                        result[name_43] = getNameOfCompilerOptionValue(value, customTypeMap);
                                     }
                                 }
                             }
@@ -51933,17 +51976,17 @@ var ts;
             var nameSize = 0;
             var valueSize = 0;
             for (var _i = 0, statistics_1 = statistics; _i < statistics_1.length; _i++) {
-                var _a = statistics_1[_i], name_43 = _a.name, value = _a.value;
-                if (name_43.length > nameSize) {
-                    nameSize = name_43.length;
+                var _a = statistics_1[_i], name_44 = _a.name, value = _a.value;
+                if (name_44.length > nameSize) {
+                    nameSize = name_44.length;
                 }
                 if (value.length > valueSize) {
                     valueSize = value.length;
                 }
             }
             for (var _b = 0, statistics_2 = statistics; _b < statistics_2.length; _b++) {
-                var _c = statistics_2[_b], name_44 = _c.name, value = _c.value;
-                ts.sys.write(padRight(name_44 + ":", nameSize + 2) + padLeft(value.toString(), valueSize) + ts.sys.newLine);
+                var _c = statistics_2[_b], name_45 = _c.name, value = _c.value;
+                ts.sys.write(padRight(name_45 + ":", nameSize + 2) + padLeft(value.toString(), valueSize) + ts.sys.newLine);
             }
         }
         function reportStatisticalValue(name, value) {
diff --git a/lib/tsserver.js b/lib/tsserver.js
index 7450ef5ab69..077dbe8115d 100644
--- a/lib/tsserver.js
+++ b/lib/tsserver.js
@@ -137,7 +137,7 @@ var ts;
 })(ts || (ts = {}));
 var ts;
 (function (ts) {
-    ts.version = "2.1.3";
+    ts.version = "2.1.4";
 })(ts || (ts = {}));
 (function (ts) {
     var createObject = Object.create;
@@ -2673,6 +2673,7 @@ var ts;
         Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword: { code: 2340, category: ts.DiagnosticCategory.Error, key: "Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword_2340", message: "Only public and protected methods of the base class are accessible via the 'super' keyword." },
         Property_0_is_private_and_only_accessible_within_class_1: { code: 2341, category: ts.DiagnosticCategory.Error, key: "Property_0_is_private_and_only_accessible_within_class_1_2341", message: "Property '{0}' is private and only accessible within class '{1}'." },
         An_index_expression_argument_must_be_of_type_string_number_symbol_or_any: { code: 2342, category: ts.DiagnosticCategory.Error, key: "An_index_expression_argument_must_be_of_type_string_number_symbol_or_any_2342", message: "An index expression argument must be of type 'string', 'number', 'symbol', or 'any'." },
+        This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1: { code: 2343, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1_2343", message: "This syntax requires an imported helper named '{1}', but module '{0}' has no exported member '{1}'." },
         Type_0_does_not_satisfy_the_constraint_1: { code: 2344, category: ts.DiagnosticCategory.Error, key: "Type_0_does_not_satisfy_the_constraint_1_2344", message: "Type '{0}' does not satisfy the constraint '{1}'." },
         Argument_of_type_0_is_not_assignable_to_parameter_of_type_1: { code: 2345, category: ts.DiagnosticCategory.Error, key: "Argument_of_type_0_is_not_assignable_to_parameter_of_type_1_2345", message: "Argument of type '{0}' is not assignable to parameter of type '{1}'." },
         Supplied_parameters_do_not_match_any_signature_of_call_target: { code: 2346, category: ts.DiagnosticCategory.Error, key: "Supplied_parameters_do_not_match_any_signature_of_call_target_2346", message: "Supplied parameters do not match any signature of call target." },
@@ -2683,6 +2684,7 @@ var ts;
         Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature: { code: 2351, category: ts.DiagnosticCategory.Error, key: "Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature_2351", message: "Cannot use 'new' with an expression whose type lacks a call or construct signature." },
         Type_0_cannot_be_converted_to_type_1: { code: 2352, category: ts.DiagnosticCategory.Error, key: "Type_0_cannot_be_converted_to_type_1_2352", message: "Type '{0}' cannot be converted to type '{1}'." },
         Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1: { code: 2353, category: ts.DiagnosticCategory.Error, key: "Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1_2353", message: "Object literal may only specify known properties, and '{0}' does not exist in type '{1}'." },
+        This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found: { code: 2354, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found_2354", message: "This syntax requires an imported helper but module '{0}' cannot be found." },
         A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value: { code: 2355, category: ts.DiagnosticCategory.Error, key: "A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value_2355", message: "A function whose declared type is neither 'void' nor 'any' must return a value." },
         An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type: { code: 2356, category: ts.DiagnosticCategory.Error, key: "An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type_2356", message: "An arithmetic operand must be of type 'any', 'number' or an enum type." },
         The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access: { code: 2357, category: ts.DiagnosticCategory.Error, key: "The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access_2357", message: "The operand of an increment or decrement operator must be a variable or a property access." },
@@ -2989,6 +2991,8 @@ var ts;
         Default_export_of_the_module_has_or_is_using_private_name_0: { code: 4082, category: ts.DiagnosticCategory.Error, key: "Default_export_of_the_module_has_or_is_using_private_name_0_4082", message: "Default export of the module has or is using private name '{0}'." },
         Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1: { code: 4083, category: ts.DiagnosticCategory.Error, key: "Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1_4083", message: "Type parameter '{0}' of exported type alias has or is using private name '{1}'." },
         Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_library_to_resolve_the_conflict: { code: 4090, category: ts.DiagnosticCategory.Message, key: "Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_librar_4090", message: "Conflicting definitions for '{0}' found at '{1}' and '{2}'. Consider installing a specific version of this library to resolve the conflict." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2: { code: 4091, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2_4091", message: "Parameter '{0}' of index signature from exported interface has or is using name '{1}' from private module '{2}'." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1: { code: 4092, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1_4092", message: "Parameter '{0}' of index signature from exported interface has or is using private name '{1}'." },
         The_current_host_does_not_support_the_0_option: { code: 5001, category: ts.DiagnosticCategory.Error, key: "The_current_host_does_not_support_the_0_option_5001", message: "The current host does not support the '{0}' option." },
         Cannot_find_the_common_subdirectory_path_for_the_input_files: { code: 5009, category: ts.DiagnosticCategory.Error, key: "Cannot_find_the_common_subdirectory_path_for_the_input_files_5009", message: "Cannot find the common subdirectory path for the input files." },
         File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0: { code: 5010, category: ts.DiagnosticCategory.Error, key: "File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0_5010", message: "File specification cannot end in a recursive directory wildcard ('**'): '{0}'." },
@@ -6965,17 +6969,17 @@ var ts;
     ts.hasChangesInResolutions = hasChangesInResolutions;
     function containsParseError(node) {
         aggregateChildData(node);
-        return (node.flags & 4194304) !== 0;
+        return (node.flags & 131072) !== 0;
     }
     ts.containsParseError = containsParseError;
     function aggregateChildData(node) {
-        if (!(node.flags & 8388608)) {
-            var thisNodeOrAnySubNodesHasError = ((node.flags & 1048576) !== 0) ||
+        if (!(node.flags & 262144)) {
+            var thisNodeOrAnySubNodesHasError = ((node.flags & 32768) !== 0) ||
                 ts.forEachChild(node, containsParseError);
             if (thisNodeOrAnySubNodesHasError) {
-                node.flags |= 4194304;
+                node.flags |= 131072;
             }
-            node.flags |= 8388608;
+            node.flags |= 262144;
         }
     }
     function getSourceFileOfNode(node) {
@@ -7199,6 +7203,10 @@ var ts;
         return false;
     }
     ts.isExternalModuleAugmentation = isExternalModuleAugmentation;
+    function isEffectiveExternalModule(node, compilerOptions) {
+        return ts.isExternalModule(node) || compilerOptions.isolatedModules;
+    }
+    ts.isEffectiveExternalModule = isEffectiveExternalModule;
     function isBlockScope(node, parentNode) {
         switch (node.kind) {
             case 261:
@@ -7954,7 +7962,7 @@ var ts;
     }
     ts.isSourceFileJavaScript = isSourceFileJavaScript;
     function isInJavaScriptFile(node) {
-        return node && !!(node.flags & 2097152);
+        return node && !!(node.flags & 65536);
     }
     ts.isInJavaScriptFile = isInJavaScriptFile;
     function isRequireCall(expression, checkArgumentIsStringLiteral) {
@@ -8193,7 +8201,7 @@ var ts;
     }
     ts.hasDeclaredRestParameter = hasDeclaredRestParameter;
     function isRestParameter(node) {
-        if (node && (node.flags & 2097152)) {
+        if (node && (node.flags & 65536)) {
             if (node.type && node.type.kind === 275 ||
                 ts.forEach(getJSDocParameterTags(node), function (t) { return t.typeExpression && t.typeExpression.type.kind === 275; })) {
                 return true;
@@ -13732,7 +13740,7 @@ var ts;
     var Parser;
     (function (Parser) {
         var scanner = ts.createScanner(5, true);
-        var disallowInAndDecoratorContext = 65536 | 262144;
+        var disallowInAndDecoratorContext = 2048 | 8192;
         var NodeConstructor;
         var TokenConstructor;
         var IdentifierConstructor;
@@ -13780,7 +13788,7 @@ var ts;
             identifiers = ts.createMap();
             identifierCount = 0;
             nodeCount = 0;
-            contextFlags = scriptKind === 1 || scriptKind === 2 ? 2097152 : 0;
+            contextFlags = scriptKind === 1 || scriptKind === 2 ? 65536 : 0;
             parseErrorBeforeNextFinishedNode = false;
             scanner.setText(sourceText);
             scanner.setOnError(scanError);
@@ -13875,16 +13883,16 @@ var ts;
             }
         }
         function setDisallowInContext(val) {
-            setContextFlag(val, 65536);
+            setContextFlag(val, 2048);
         }
         function setYieldContext(val) {
-            setContextFlag(val, 131072);
+            setContextFlag(val, 4096);
         }
         function setDecoratorContext(val) {
-            setContextFlag(val, 262144);
+            setContextFlag(val, 8192);
         }
         function setAwaitContext(val) {
-            setContextFlag(val, 524288);
+            setContextFlag(val, 16384);
         }
         function doOutsideOfContext(context, func) {
             var contextFlagsToClear = context & contextFlags;
@@ -13907,40 +13915,40 @@ var ts;
             return func();
         }
         function allowInAnd(func) {
-            return doOutsideOfContext(65536, func);
+            return doOutsideOfContext(2048, func);
         }
         function disallowInAnd(func) {
-            return doInsideOfContext(65536, func);
+            return doInsideOfContext(2048, func);
         }
         function doInYieldContext(func) {
-            return doInsideOfContext(131072, func);
+            return doInsideOfContext(4096, func);
         }
         function doInDecoratorContext(func) {
-            return doInsideOfContext(262144, func);
+            return doInsideOfContext(8192, func);
         }
         function doInAwaitContext(func) {
-            return doInsideOfContext(524288, func);
+            return doInsideOfContext(16384, func);
         }
         function doOutsideOfAwaitContext(func) {
-            return doOutsideOfContext(524288, func);
+            return doOutsideOfContext(16384, func);
         }
         function doInYieldAndAwaitContext(func) {
-            return doInsideOfContext(131072 | 524288, func);
+            return doInsideOfContext(4096 | 16384, func);
         }
         function inContext(flags) {
             return (contextFlags & flags) !== 0;
         }
         function inYieldContext() {
-            return inContext(131072);
+            return inContext(4096);
         }
         function inDisallowInContext() {
-            return inContext(65536);
+            return inContext(2048);
         }
         function inDecoratorContext() {
-            return inContext(262144);
+            return inContext(8192);
         }
         function inAwaitContext() {
-            return inContext(524288);
+            return inContext(16384);
         }
         function parseErrorAtCurrentToken(message, arg0) {
             var start = scanner.getTokenPos();
@@ -14102,7 +14110,7 @@ var ts;
             }
             if (parseErrorBeforeNextFinishedNode) {
                 parseErrorBeforeNextFinishedNode = false;
-                node.flags |= 1048576;
+                node.flags |= 32768;
             }
             return node;
         }
@@ -14420,7 +14428,7 @@ var ts;
             if (ts.containsParseError(node)) {
                 return undefined;
             }
-            var nodeContextFlags = node.flags & 3080192;
+            var nodeContextFlags = node.flags & 96256;
             if (nodeContextFlags !== contextFlags) {
                 return undefined;
             }
@@ -15228,7 +15236,7 @@ var ts;
             }
         }
         function parseType() {
-            return doOutsideOfContext(655360, parseTypeWorker);
+            return doOutsideOfContext(20480, parseTypeWorker);
         }
         function parseTypeWorker() {
             if (isStartOfFunctionType()) {
@@ -16859,7 +16867,7 @@ var ts;
             property.type = parseTypeAnnotation();
             property.initializer = ts.hasModifier(property, 32)
                 ? allowInAnd(parseNonParameterInitializer)
-                : doOutsideOfContext(131072 | 65536, parseNonParameterInitializer);
+                : doOutsideOfContext(4096 | 2048, parseNonParameterInitializer);
             parseSemicolon();
             return addJSDocComment(finishNode(property));
         }
@@ -18833,7 +18841,7 @@ var ts;
                 activeLabels = undefined;
                 hasExplicitReturn = false;
                 bindChildren(node);
-                node.flags &= ~64896;
+                node.flags &= ~1408;
                 if (!(currentFlow.flags & 1) && containerFlags & 8 && ts.nodeIsPresent(node.body)) {
                     node.flags |= 128;
                     if (hasExplicitReturn)
@@ -20016,9 +20024,6 @@ var ts;
                     return bindParameter(node);
                 case 223:
                 case 174:
-                    if (node.dotDotDotToken && node.parent.kind === 172) {
-                        emitFlags |= 32768;
-                    }
                     return bindVariableDeclarationOrBindingElement(node);
                 case 147:
                 case 146:
@@ -20045,7 +20050,6 @@ var ts;
                         }
                         root = root.parent;
                     }
-                    emitFlags |= hasRest ? 32768 : 16384;
                     return;
                 case 153:
                 case 154:
@@ -20241,14 +20245,6 @@ var ts;
             }
         }
         function bindClassLikeDeclaration(node) {
-            if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
-                if (ts.getClassExtendsHeritageClauseElement(node) !== undefined) {
-                    emitFlags |= 1024;
-                }
-                if (ts.nodeIsDecorated(node)) {
-                    emitFlags |= 2048;
-                }
-            }
             if (node.kind === 226) {
                 bindBlockScopedDeclaration(node, 32, 899519);
             }
@@ -20292,11 +20288,6 @@ var ts;
             }
         }
         function bindParameter(node) {
-            if (!ts.isDeclarationFile(file) &&
-                !ts.isInAmbientContext(node) &&
-                ts.nodeIsDecorated(node)) {
-                emitFlags |= (2048 | 4096);
-            }
             if (inStrictMode) {
                 checkStrictModeEvalOrArguments(node, node.name);
             }
@@ -20314,7 +20305,7 @@ var ts;
         function bindFunctionDeclaration(node) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192;
+                    emitFlags |= 1024;
                 }
             }
             checkStrictModeFunctionName(node);
@@ -20329,7 +20320,7 @@ var ts;
         function bindFunctionExpression(node) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192;
+                    emitFlags |= 1024;
                 }
             }
             if (currentFlow) {
@@ -20342,10 +20333,7 @@ var ts;
         function bindPropertyOrMethodOrAccessor(node, symbolFlags, symbolExcludes) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192;
-                }
-                if (ts.nodeIsDecorated(node)) {
-                    emitFlags |= 2048;
+                    emitFlags |= 1024;
                 }
             }
             if (currentFlow && ts.isObjectLiteralOrClassExpressionMethod(node)) {
@@ -21053,6 +21041,8 @@ var ts;
     ts.getSymbolId = getSymbolId;
     function createTypeChecker(host, produceDiagnostics) {
         var cancellationToken;
+        var requestedExternalEmitHelpers;
+        var externalHelpersModule;
         var Symbol = ts.objectAllocator.getSymbolConstructor();
         var Type = ts.objectAllocator.getTypeConstructor();
         var Signature = ts.objectAllocator.getSignatureConstructor();
@@ -23381,7 +23371,13 @@ var ts;
             return name.kind === 142 && !ts.isStringOrNumericLiteral(name.expression);
         }
         function getRestType(source, properties, symbol) {
-            ts.Debug.assert(!!(source.flags & 32768), "Rest types only support object types right now.");
+            source = filterType(source, function (t) { return !(t.flags & 6144); });
+            if (source.flags & 8192) {
+                return emptyObjectType;
+            }
+            if (source.flags & 65536) {
+                return mapType(source, function (t) { return getRestType(t, properties, symbol); });
+            }
             var members = ts.createMap();
             var names = ts.createMap();
             for (var _i = 0, properties_2 = properties; _i < properties_2.length; _i++) {
@@ -23417,7 +23413,7 @@ var ts;
             var type;
             if (pattern.kind === 172) {
                 if (declaration.dotDotDotToken) {
-                    if (!(parentType.flags & 32768)) {
+                    if (!isValidSpreadType(parentType)) {
                         error(declaration, ts.Diagnostics.Rest_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
@@ -23495,7 +23491,7 @@ var ts;
             return strictNullChecks && optional ? includeFalsyTypes(type, 2048) : type;
         }
         function getTypeForVariableLikeDeclaration(declaration, includeOptionality) {
-            if (declaration.flags & 2097152) {
+            if (declaration.flags & 65536) {
                 var type = getTypeForVariableLikeDeclarationFromJSDocComment(declaration);
                 if (type && type !== unknownType) {
                     return type;
@@ -23514,7 +23510,7 @@ var ts;
             if (declaration.type) {
                 return addOptionality(getTypeFromTypeNode(declaration.type), declaration.questionToken && includeOptionality);
             }
-            if ((compilerOptions.noImplicitAny || declaration.flags & 2097152) &&
+            if ((compilerOptions.noImplicitAny || declaration.flags & 65536) &&
                 declaration.kind === 223 && !ts.isBindingPattern(declaration.name) &&
                 !(ts.getCombinedModifierFlags(declaration) & 1) && !ts.isInAmbientContext(declaration)) {
                 if (!(ts.getCombinedNodeFlags(declaration) & 2) && (!declaration.initializer || isNullOrUndefined(declaration.initializer))) {
@@ -23575,13 +23571,18 @@ var ts;
         }
         function getTypeFromObjectBindingPattern(pattern, includePatternInType, reportErrors) {
             var members = ts.createMap();
+            var stringIndexInfo;
             var hasComputedProperties = false;
             ts.forEach(pattern.elements, function (e) {
                 var name = e.propertyName || e.name;
-                if (isComputedNonLiteralName(name) || e.dotDotDotToken) {
+                if (isComputedNonLiteralName(name)) {
                     hasComputedProperties = true;
                     return;
                 }
+                if (e.dotDotDotToken) {
+                    stringIndexInfo = createIndexInfo(anyType, false);
+                    return;
+                }
                 var text = ts.getTextOfPropertyName(name);
                 var flags = 4 | 67108864 | (e.initializer ? 536870912 : 0);
                 var symbol = createSymbol(flags, text);
@@ -23589,7 +23590,7 @@ var ts;
                 symbol.bindingElement = e;
                 members[symbol.name] = symbol;
             });
-            var result = createAnonymousType(undefined, members, emptyArray, emptyArray, undefined, undefined);
+            var result = createAnonymousType(undefined, members, emptyArray, emptyArray, stringIndexInfo, undefined);
             if (includePatternInType) {
                 result.pattern = pattern;
             }
@@ -23654,7 +23655,7 @@ var ts;
                 if (declaration.kind === 240) {
                     return links.type = checkExpression(declaration.expression);
                 }
-                if (declaration.flags & 2097152 && declaration.kind === 286 && declaration.typeExpression) {
+                if (declaration.flags & 65536 && declaration.kind === 286 && declaration.typeExpression) {
                     return links.type = getTypeFromTypeNode(declaration.typeExpression.type);
                 }
                 if (!pushTypeResolution(symbol, 0)) {
@@ -23663,7 +23664,7 @@ var ts;
                 var type = void 0;
                 if (declaration.kind === 192 ||
                     declaration.kind === 177 && declaration.parent.kind === 192) {
-                    if (declaration.flags & 2097152) {
+                    if (declaration.flags & 65536) {
                         var jsdocType = ts.getJSDocType(declaration.parent);
                         if (jsdocType) {
                             return links.type = getTypeFromTypeNode(jsdocType);
@@ -23717,7 +23718,7 @@ var ts;
             if (!links.type) {
                 var getter = ts.getDeclarationOfKind(symbol, 151);
                 var setter = ts.getDeclarationOfKind(symbol, 152);
-                if (getter && getter.flags & 2097152) {
+                if (getter && getter.flags & 65536) {
                     var jsDocType = getTypeForVariableLikeDeclarationFromJSDocComment(getter);
                     if (jsDocType) {
                         return links.type = jsDocType;
@@ -24588,7 +24589,7 @@ var ts;
                     var isomorphicProp = isomorphicType && getPropertyOfType(isomorphicType, propName);
                     var isOptional = templateOptional || !!(isomorphicProp && isomorphicProp.flags & 536870912);
                     var prop = createSymbol(4 | 67108864 | (isOptional ? 536870912 : 0), propName);
-                    prop.type = addOptionality(propType, isOptional);
+                    prop.type = propType;
                     prop.isReadonly = templateReadonly || isomorphicProp && isReadonlySymbol(isomorphicProp);
                     members[propName] = prop;
                 }
@@ -24609,7 +24610,7 @@ var ts;
         function getTemplateTypeFromMappedType(type) {
             return type.templateType ||
                 (type.templateType = type.declaration.type ?
-                    instantiateType(getTypeFromTypeNode(type.declaration.type), type.mapper || identityMapper) :
+                    instantiateType(addOptionality(getTypeFromTypeNode(type.declaration.type), !!type.declaration.questionToken), type.mapper || identityMapper) :
                     unknownType);
         }
         function getIsomorphicTypeFromMappedType(type) {
@@ -24858,7 +24859,7 @@ var ts;
             return undefined;
         }
         function getTypeParametersFromJSDocTemplate(declaration) {
-            if (declaration.flags & 2097152) {
+            if (declaration.flags & 65536) {
                 var templateTag = ts.getJSDocTemplateTag(declaration);
                 if (templateTag) {
                     return getTypeParametersFromDeclaration(templateTag.typeParameters);
@@ -24886,7 +24887,7 @@ var ts;
             return result;
         }
         function isJSDocOptionalParameter(node) {
-            if (node.flags & 2097152) {
+            if (node.flags & 65536) {
                 if (node.type && node.type.kind === 273) {
                     return true;
                 }
@@ -25015,7 +25016,7 @@ var ts;
             else if (declaration.type) {
                 return getTypeFromTypeNode(declaration.type);
             }
-            if (declaration.flags & 2097152) {
+            if (declaration.flags & 65536) {
                 var type = getReturnTypeFromJSDocComment(declaration);
                 if (type && type !== unknownType) {
                     return type;
@@ -25822,7 +25823,7 @@ var ts;
             }
             var mapper = createUnaryTypeMapper(getTypeParameterFromMappedType(type), indexType);
             var templateMapper = type.mapper ? combineTypeMappers(type.mapper, mapper) : mapper;
-            return addOptionality(instantiateType(getTemplateTypeFromMappedType(type), templateMapper), !!type.declaration.questionToken);
+            return instantiateType(getTemplateTypeFromMappedType(type), templateMapper);
         }
         function getIndexedAccessType(objectType, indexType, accessNode) {
             if (indexType.flags & 16384 ||
@@ -25898,10 +25899,23 @@ var ts;
             return symbol ? getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol) : undefined;
         }
         function getSpreadType(left, right, isFromObjectLiteral) {
-            ts.Debug.assert(!!(left.flags & (32768 | 1)) && !!(right.flags & (32768 | 1)), "Only object types may be spread.");
             if (left.flags & 1 || right.flags & 1) {
                 return anyType;
             }
+            left = filterType(left, function (t) { return !(t.flags & 6144); });
+            if (left.flags & 8192) {
+                return right;
+            }
+            right = filterType(right, function (t) { return !(t.flags & 6144); });
+            if (right.flags & 8192) {
+                return left;
+            }
+            if (left.flags & 65536) {
+                return mapType(left, function (t) { return getSpreadType(t, right, isFromObjectLiteral); });
+            }
+            if (right.flags & 65536) {
+                return mapType(right, function (t) { return getSpreadType(left, t, isFromObjectLiteral); });
+            }
             var members = ts.createMap();
             var skippedPrivateMembers = ts.createMap();
             var stringIndexInfo;
@@ -27826,6 +27840,8 @@ var ts;
             var typeInferences = createTypeInferencesObject();
             var typeInferencesArray = [typeInferences];
             var templateType = getTemplateTypeFromMappedType(target);
+            var readonlyMask = target.declaration.readonlyToken ? false : true;
+            var optionalMask = target.declaration.questionToken ? 0 : 536870912;
             var properties = getPropertiesOfType(source);
             var members = createSymbolTable(properties);
             var hasInferredTypes = false;
@@ -27833,10 +27849,10 @@ var ts;
                 var prop = properties_4[_i];
                 var inferredPropType = inferTargetType(getTypeOfSymbol(prop));
                 if (inferredPropType) {
-                    var inferredProp = createSymbol(4 | 67108864 | prop.flags & 536870912, prop.name);
+                    var inferredProp = createSymbol(4 | 67108864 | prop.flags & optionalMask, prop.name);
                     inferredProp.declarations = prop.declarations;
                     inferredProp.type = inferredPropType;
-                    inferredProp.isReadonly = isReadonlySymbol(prop);
+                    inferredProp.isReadonly = readonlyMask && isReadonlySymbol(prop);
                     members[prop.name] = inferredProp;
                     hasInferredTypes = true;
                 }
@@ -27845,7 +27861,7 @@ var ts;
             if (indexInfo) {
                 var inferredIndexType = inferTargetType(indexInfo.type);
                 if (inferredIndexType) {
-                    indexInfo = createIndexInfo(inferredIndexType, indexInfo.isReadonly);
+                    indexInfo = createIndexInfo(inferredIndexType, readonlyMask && indexInfo.isReadonly);
                     hasInferredTypes = true;
                 }
             }
@@ -29182,7 +29198,7 @@ var ts;
                         error(node, ts.Diagnostics.The_arguments_object_cannot_be_referenced_in_an_async_function_or_method_in_ES3_and_ES5_Consider_using_a_standard_function_or_method);
                     }
                 }
-                if (node.flags & 524288) {
+                if (node.flags & 16384) {
                     getNodeLinks(container).flags |= 8192;
                 }
                 return getTypeOfSymbol(symbol);
@@ -30095,7 +30111,7 @@ var ts;
                         if (impliedProp) {
                             prop.flags |= impliedProp.flags & 536870912;
                         }
-                        else if (!compilerOptions.suppressExcessPropertyErrors) {
+                        else if (!compilerOptions.suppressExcessPropertyErrors && !getIndexInfoOfType(contextualType, 0)) {
                             error(memberDecl.name, ts.Diagnostics.Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1, symbolToString(member), typeToString(contextualType));
                         }
                     }
@@ -30109,6 +30125,9 @@ var ts;
                     member = prop;
                 }
                 else if (memberDecl.kind === 259) {
+                    if (languageVersion < 5) {
+                        checkExternalEmitHelpers(memberDecl, 2);
+                    }
                     if (propertiesArray.length > 0) {
                         spread = getSpreadType(spread, createObjectLiteralType(), true);
                         propertiesArray = [];
@@ -30118,7 +30137,7 @@ var ts;
                         typeFlags = 0;
                     }
                     var type = checkExpression(memberDecl.expression);
-                    if (!(type.flags & (32768 | 1))) {
+                    if (!isValidSpreadType(type)) {
                         error(memberDecl, ts.Diagnostics.Spread_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
@@ -30183,6 +30202,11 @@ var ts;
                 return result;
             }
         }
+        function isValidSpreadType(type) {
+            return !!(type.flags & (1 | 4096 | 2048) ||
+                type.flags & 32768 && !isGenericMappedType(type) ||
+                type.flags & 196608 && !ts.forEach(type.types, function (t) { return !isValidSpreadType(t); }));
+        }
         function checkJsxSelfClosingElement(node) {
             checkJsxOpeningLikeElement(node);
             return jsxElementType || anyType;
@@ -30257,6 +30281,9 @@ var ts;
             return exprType;
         }
         function checkJsxSpreadAttribute(node, elementAttributesType, nameTable) {
+            if (compilerOptions.jsx === 2) {
+                checkExternalEmitHelpers(node, 2);
+            }
             var type = checkExpression(node.expression);
             var props = getPropertiesOfType(type);
             for (var _i = 0, props_2 = props; _i < props_2.length; _i++) {
@@ -32003,7 +32030,7 @@ var ts;
         }
         function checkAwaitExpression(node) {
             if (produceDiagnostics) {
-                if (!(node.flags & 524288)) {
+                if (!(node.flags & 16384)) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.await_expression_is_only_allowed_within_an_async_function);
                 }
                 if (isInParameterInitializerBeforeContainingFunction(node)) {
@@ -32161,6 +32188,9 @@ var ts;
                 }
             }
             else if (property.kind === 259) {
+                if (languageVersion < 5) {
+                    checkExternalEmitHelpers(property, 4);
+                }
                 var nonRestNames = [];
                 if (allProperties) {
                     for (var i = 0; i < allProperties.length - 1; i++) {
@@ -32511,7 +32541,7 @@ var ts;
         }
         function checkYieldExpression(node) {
             if (produceDiagnostics) {
-                if (!(node.flags & 131072) || isYieldExpressionInClass(node)) {
+                if (!(node.flags & 4096) || isYieldExpressionInClass(node)) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.A_yield_expression_is_only_allowed_in_a_generator_body);
                 }
                 if (isInParameterInitializerBeforeContainingFunction(node)) {
@@ -32887,6 +32917,12 @@ var ts;
                 node.kind === 154) {
                 checkGrammarFunctionLikeDeclaration(node);
             }
+            if (ts.isAsyncFunctionLike(node) && languageVersion < 4) {
+                checkExternalEmitHelpers(node, 64);
+                if (languageVersion < 2) {
+                    checkExternalEmitHelpers(node, 128);
+                }
+            }
             checkTypeParameters(node.typeParameters);
             ts.forEach(node.parameters, checkParameter);
             if (node.type) {
@@ -33681,7 +33717,13 @@ var ts;
             if (!compilerOptions.experimentalDecorators) {
                 error(node, ts.Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning);
             }
+            var firstDecorator = node.decorators[0];
+            checkExternalEmitHelpers(firstDecorator, 8);
+            if (node.kind === 144) {
+                checkExternalEmitHelpers(firstDecorator, 32);
+            }
             if (compilerOptions.emitDecoratorMetadata) {
+                checkExternalEmitHelpers(firstDecorator, 16);
                 switch (node.kind) {
                     case 226:
                         var constructor = ts.getFirstConstructorWithBody(node);
@@ -33998,14 +34040,14 @@ var ts;
             }
         }
         function checkCollisionWithGlobalPromiseInGeneratedCode(node, name) {
-            if (!needCollisionCheckForIdentifier(node, name, "Promise")) {
+            if (languageVersion >= 4 || !needCollisionCheckForIdentifier(node, name, "Promise")) {
                 return;
             }
             if (node.kind === 230 && ts.getModuleInstanceState(node) !== 1) {
                 return;
             }
             var parent = getDeclarationContainer(node);
-            if (parent.kind === 261 && ts.isExternalOrCommonJsModule(parent) && parent.flags & 8192) {
+            if (parent.kind === 261 && ts.isExternalOrCommonJsModule(parent) && parent.flags & 1024) {
                 error(name, ts.Diagnostics.Duplicate_identifier_0_Compiler_reserves_name_1_in_top_level_scope_of_a_module_containing_async_functions, ts.declarationNameToString(name), ts.declarationNameToString(name));
             }
         }
@@ -34102,6 +34144,9 @@ var ts;
                 }
             }
             if (node.kind === 174) {
+                if (node.parent.kind === 172 && languageVersion < 5) {
+                    checkExternalEmitHelpers(node, 4);
+                }
                 if (node.propertyName && node.propertyName.kind === 142) {
                     checkComputedPropertyName(node.propertyName);
                 }
@@ -34511,7 +34556,7 @@ var ts;
         }
         function checkWithStatement(node) {
             if (!checkGrammarStatementInAmbientContext(node)) {
-                if (node.flags & 524288) {
+                if (node.flags & 16384) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.with_statements_are_not_allowed_in_an_async_function_block);
                 }
             }
@@ -34757,6 +34802,9 @@ var ts;
             checkClassForDuplicateDeclarations(node);
             var baseTypeNode = ts.getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
+                if (languageVersion < 2) {
+                    checkExternalEmitHelpers(baseTypeNode.parent, 1);
+                }
                 var baseTypes = getBaseTypes(type);
                 if (baseTypes.length && produceDiagnostics) {
                     var baseType_1 = baseTypes[0];
@@ -36664,8 +36712,6 @@ var ts;
                 ts.bindSourceFile(file, compilerOptions);
             }
             var augmentations;
-            var requestedExternalEmitHelpers = 0;
-            var firstFileRequestingExternalHelpers;
             for (var _b = 0, _c = host.getSourceFiles(); _b < _c.length; _b++) {
                 var file = _c[_b];
                 if (!ts.isExternalOrCommonJsModule(file)) {
@@ -36685,15 +36731,6 @@ var ts;
                         }
                     }
                 }
-                if ((compilerOptions.isolatedModules || ts.isExternalModule(file)) && !file.isDeclarationFile) {
-                    var fileRequestedExternalEmitHelpers = file.flags & 64512;
-                    if (fileRequestedExternalEmitHelpers) {
-                        requestedExternalEmitHelpers |= fileRequestedExternalEmitHelpers;
-                        if (firstFileRequestingExternalHelpers === undefined) {
-                            firstFileRequestingExternalHelpers = file;
-                        }
-                    }
-                }
             }
             if (augmentations) {
                 for (var _d = 0, augmentations_1 = augmentations; _d < augmentations_1.length; _d++) {
@@ -36748,44 +36785,46 @@ var ts;
             var symbol = getGlobalSymbol("ReadonlyArray", 793064, undefined);
             globalReadonlyArrayType = symbol && getTypeOfGlobalSymbol(symbol, 1);
             anyReadonlyArrayType = globalReadonlyArrayType ? createTypeFromGenericGlobalType(globalReadonlyArrayType, [anyType]) : anyArrayType;
-            if (compilerOptions.importHelpers && firstFileRequestingExternalHelpers) {
-                var helpersModule = resolveExternalModule(firstFileRequestingExternalHelpers, ts.externalHelpersModuleNameText, ts.Diagnostics.Cannot_find_module_0, undefined);
-                if (helpersModule) {
-                    var exports_2 = helpersModule.exports;
-                    if (requestedExternalEmitHelpers & 1024 && languageVersion < 2) {
-                        verifyHelperSymbol(exports_2, "__extends", 107455);
-                    }
-                    if (requestedExternalEmitHelpers & 16384 &&
-                        (languageVersion < 5 || compilerOptions.jsx === 2)) {
-                        verifyHelperSymbol(exports_2, "__assign", 107455);
-                    }
-                    if (languageVersion < 5 && requestedExternalEmitHelpers & 32768) {
-                        verifyHelperSymbol(exports_2, "__rest", 107455);
-                    }
-                    if (requestedExternalEmitHelpers & 2048) {
-                        verifyHelperSymbol(exports_2, "__decorate", 107455);
-                        if (compilerOptions.emitDecoratorMetadata) {
-                            verifyHelperSymbol(exports_2, "__metadata", 107455);
-                        }
-                    }
-                    if (requestedExternalEmitHelpers & 4096) {
-                        verifyHelperSymbol(exports_2, "__param", 107455);
-                    }
-                    if (requestedExternalEmitHelpers & 8192) {
-                        verifyHelperSymbol(exports_2, "__awaiter", 107455);
-                        if (languageVersion < 2) {
-                            verifyHelperSymbol(exports_2, "__generator", 107455);
+        }
+        function checkExternalEmitHelpers(location, helpers) {
+            if ((requestedExternalEmitHelpers & helpers) !== helpers && compilerOptions.importHelpers) {
+                var sourceFile = ts.getSourceFileOfNode(location);
+                if (ts.isEffectiveExternalModule(sourceFile, compilerOptions)) {
+                    var helpersModule = resolveHelpersModule(sourceFile, location);
+                    if (helpersModule !== unknownSymbol) {
+                        var uncheckedHelpers = helpers & ~requestedExternalEmitHelpers;
+                        for (var helper = 1; helper <= 128; helper <<= 1) {
+                            if (uncheckedHelpers & helper) {
+                                var name_29 = getHelperName(helper);
+                                var symbol = getSymbol(helpersModule.exports, ts.escapeIdentifier(name_29), 107455);
+                                if (!symbol) {
+                                    error(location, ts.Diagnostics.This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1, ts.externalHelpersModuleNameText, name_29);
+                                }
+                            }
                         }
                     }
+                    requestedExternalEmitHelpers |= helpers;
                 }
             }
         }
-        function verifyHelperSymbol(symbols, name, meaning) {
-            var symbol = getSymbol(symbols, ts.escapeIdentifier(name), meaning);
-            if (!symbol) {
-                error(undefined, ts.Diagnostics.Module_0_has_no_exported_member_1, ts.externalHelpersModuleNameText, name);
+        function getHelperName(helper) {
+            switch (helper) {
+                case 1: return "__extends";
+                case 2: return "__assign";
+                case 4: return "__rest";
+                case 8: return "__decorate";
+                case 16: return "__metadata";
+                case 32: return "__param";
+                case 64: return "__awaiter";
+                case 128: return "__generator";
             }
         }
+        function resolveHelpersModule(node, errorNode) {
+            if (!externalHelpersModule) {
+                externalHelpersModule = resolveExternalModule(node, ts.externalHelpersModuleNameText, ts.Diagnostics.This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found, errorNode) || unknownSymbol;
+            }
+            return externalHelpersModule;
+        }
         function createInstantiatedPromiseLikeType() {
             var promiseLikeType = getGlobalPromiseLikeType();
             if (promiseLikeType !== emptyGenericType) {
@@ -37308,9 +37347,9 @@ var ts;
                 if (prop.kind === 259) {
                     continue;
                 }
-                var name_29 = prop.name;
-                if (name_29.kind === 142) {
-                    checkGrammarComputedPropertyName(name_29);
+                var name_30 = prop.name;
+                if (name_30.kind === 142) {
+                    checkGrammarComputedPropertyName(name_30);
                 }
                 if (prop.kind === 258 && !inDestructuring && prop.objectAssignmentInitializer) {
                     return grammarErrorOnNode(prop.equalsToken, ts.Diagnostics.can_only_be_used_in_an_object_literal_property_inside_a_destructuring_assignment);
@@ -37326,8 +37365,8 @@ var ts;
                 var currentKind = void 0;
                 if (prop.kind === 257 || prop.kind === 258) {
                     checkGrammarForInvalidQuestionMark(prop.questionToken, ts.Diagnostics.An_object_member_cannot_be_declared_optional);
-                    if (name_29.kind === 8) {
-                        checkGrammarNumericLiteral(name_29);
+                    if (name_30.kind === 8) {
+                        checkGrammarNumericLiteral(name_30);
                     }
                     currentKind = Property;
                 }
@@ -37343,7 +37382,7 @@ var ts;
                 else {
                     ts.Debug.fail("Unexpected syntax kind:" + prop.kind);
                 }
-                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_29);
+                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_30);
                 if (effectiveName === undefined) {
                     continue;
                 }
@@ -37353,18 +37392,18 @@ var ts;
                 else {
                     var existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
-                        grammarErrorOnNode(name_29, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_29));
+                        grammarErrorOnNode(name_30, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_30));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
                             seen[effectiveName] = currentKind | existingKind;
                         }
                         else {
-                            return grammarErrorOnNode(name_29, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
+                            return grammarErrorOnNode(name_30, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
                         }
                     }
                     else {
-                        return grammarErrorOnNode(name_29, ts.Diagnostics.An_object_literal_cannot_have_property_and_accessor_with_the_same_name);
+                        return grammarErrorOnNode(name_30, ts.Diagnostics.An_object_literal_cannot_have_property_and_accessor_with_the_same_name);
                     }
                 }
             }
@@ -37377,12 +37416,12 @@ var ts;
                     continue;
                 }
                 var jsxAttr = attr;
-                var name_30 = jsxAttr.name;
-                if (!seen[name_30.text]) {
-                    seen[name_30.text] = true;
+                var name_31 = jsxAttr.name;
+                if (!seen[name_31.text]) {
+                    seen[name_31.text] = true;
                 }
                 else {
-                    return grammarErrorOnNode(name_30, ts.Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
+                    return grammarErrorOnNode(name_31, ts.Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
                 }
                 var initializer = jsxAttr.initializer;
                 if (initializer && initializer.kind === 252 && !initializer.expression) {
@@ -38700,10 +38739,10 @@ var ts;
             }
         }
         for (var _i = 0, pendingDeclarations_1 = pendingDeclarations; _i < pendingDeclarations_1.length; _i++) {
-            var _a = pendingDeclarations_1[_i], pendingExpressions_1 = _a.pendingExpressions, name_31 = _a.name, value = _a.value, location_2 = _a.location, original = _a.original;
-            var variable = ts.createVariableDeclaration(name_31, undefined, pendingExpressions_1 ? ts.inlineExpressions(ts.append(pendingExpressions_1, value)) : value, location_2);
+            var _a = pendingDeclarations_1[_i], pendingExpressions_1 = _a.pendingExpressions, name_32 = _a.name, value = _a.value, location_2 = _a.location, original = _a.original;
+            var variable = ts.createVariableDeclaration(name_32, undefined, pendingExpressions_1 ? ts.inlineExpressions(ts.append(pendingExpressions_1, value)) : value, location_2);
             variable.original = original;
-            if (ts.isIdentifier(name_31)) {
+            if (ts.isIdentifier(name_32)) {
                 ts.setEmitFlags(variable, 64);
             }
             ts.aggregateTransformFlags(variable);
@@ -38849,8 +38888,8 @@ var ts;
             return ts.createElementAccess(value, argumentExpression);
         }
         else {
-            var name_32 = ts.createIdentifier(ts.unescapeIdentifier(propertyName.text));
-            return ts.createPropertyAccess(value, name_32);
+            var name_33 = ts.createIdentifier(ts.unescapeIdentifier(propertyName.text));
+            return ts.createPropertyAccess(value, name_33);
         }
     }
     function ensureIdentifier(flattenContext, value, reuseIdentifierExpressions, location) {
@@ -38892,7 +38931,7 @@ var ts;
     var restHelper = {
         name: "typescript:rest",
         scoped: false,
-        text: "\n            var __rest = (this && this.__rest) || function (s, e) {\n                var t = {};\n                for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)\n                    t[p] = s[p];\n                if (typeof Object.getOwnPropertySymbols === \"function\")\n                    for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)\n                        t[p[i]] = s[p[i]];\n                return t;\n            };"
+        text: "\n            var __rest = (this && this.__rest) || function (s, e) {\n                var t = {};\n                for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)\n                    t[p] = s[p];\n                if (s != null && typeof Object.getOwnPropertySymbols === \"function\")\n                    for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)\n                        t[p[i]] = s[p[i]];\n                return t;\n            };"
     };
     function createRestCall(context, value, elements, computedTempVariables, location) {
         context.requestEmitHelper(restHelper);
@@ -39762,14 +39801,14 @@ var ts;
         function serializeEntityNameAsExpression(node, useFallback) {
             switch (node.kind) {
                 case 70:
-                    var name_33 = ts.getMutableClone(node);
-                    name_33.flags &= ~8;
-                    name_33.original = undefined;
-                    name_33.parent = currentScope;
+                    var name_34 = ts.getMutableClone(node);
+                    name_34.flags &= ~8;
+                    name_34.original = undefined;
+                    name_34.parent = currentScope;
                     if (useFallback) {
-                        return ts.createLogicalAnd(ts.createStrictInequality(ts.createTypeOf(name_33), ts.createLiteral("undefined")), name_33);
+                        return ts.createLogicalAnd(ts.createStrictInequality(ts.createTypeOf(name_34), ts.createLiteral("undefined")), name_34);
                     }
-                    return name_33;
+                    return name_34;
                 case 141:
                     return serializeQualifiedNameAsExpression(node, useFallback);
             }
@@ -39799,7 +39838,7 @@ var ts;
                     : name.expression;
             }
             else if (ts.isIdentifier(name)) {
-                return ts.createLiteral(name.text);
+                return ts.createLiteral(ts.unescapeIdentifier(name.text));
             }
             else {
                 return ts.getSynthesizedClone(name);
@@ -40040,9 +40079,9 @@ var ts;
         }
         function isFirstEmittedDeclarationInScope(node) {
             if (currentScopeFirstDeclarationsOfName) {
-                var name_34 = node.symbol && node.symbol.name;
-                if (name_34) {
-                    return currentScopeFirstDeclarationsOfName[name_34] === node;
+                var name_35 = node.symbol && node.symbol.name;
+                if (name_35) {
+                    return currentScopeFirstDeclarationsOfName[name_35] === node;
                 }
             }
             return false;
@@ -40331,14 +40370,14 @@ var ts;
         }
         function substituteShorthandPropertyAssignment(node) {
             if (enabledSubstitutions & 2) {
-                var name_35 = node.name;
-                var exportedName = trySubstituteNamespaceExportedName(name_35);
+                var name_36 = node.name;
+                var exportedName = trySubstituteNamespaceExportedName(name_36);
                 if (exportedName) {
                     if (node.objectAssignmentInitializer) {
                         var initializer = ts.createAssignment(exportedName, node.objectAssignmentInitializer);
-                        return ts.createPropertyAssignment(name_35, initializer, node);
+                        return ts.createPropertyAssignment(name_36, initializer, node);
                     }
-                    return ts.createPropertyAssignment(name_35, exportedName, node);
+                    return ts.createPropertyAssignment(name_36, exportedName, node);
                 }
             }
             return node;
@@ -40859,12 +40898,12 @@ var ts;
                 return getTagName(node.openingElement);
             }
             else {
-                var name_36 = node.tagName;
-                if (ts.isIdentifier(name_36) && ts.isIntrinsicJsxName(name_36.text)) {
-                    return ts.createLiteral(name_36.text);
+                var name_37 = node.tagName;
+                if (ts.isIdentifier(name_37) && ts.isIntrinsicJsxName(name_37.text)) {
+                    return ts.createLiteral(name_37.text);
                 }
                 else {
-                    return ts.createExpressionFromEntityName(name_36);
+                    return ts.createExpressionFromEntityName(name_37);
                 }
             }
         }
@@ -41997,15 +42036,15 @@ var ts;
             }
             for (var _i = 0, _a = node.parameters; _i < _a.length; _i++) {
                 var parameter = _a[_i];
-                var name_37 = parameter.name, initializer = parameter.initializer, dotDotDotToken = parameter.dotDotDotToken;
+                var name_38 = parameter.name, initializer = parameter.initializer, dotDotDotToken = parameter.dotDotDotToken;
                 if (dotDotDotToken) {
                     continue;
                 }
-                if (ts.isBindingPattern(name_37)) {
-                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name_37, initializer);
+                if (ts.isBindingPattern(name_38)) {
+                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name_38, initializer);
                 }
                 else if (initializer) {
-                    addDefaultValueAssignmentForInitializer(statements, parameter, name_37, initializer);
+                    addDefaultValueAssignmentForInitializer(statements, parameter, name_38, initializer);
                 }
             }
         }
@@ -44010,9 +44049,9 @@ var ts;
                 if (ts.isIdentifier(original) && original.parent) {
                     var declaration = resolver.getReferencedValueDeclaration(original);
                     if (declaration) {
-                        var name_38 = ts.getProperty(renamedCatchVariableDeclarations, String(ts.getOriginalNodeId(declaration)));
-                        if (name_38) {
-                            var clone_6 = ts.getMutableClone(name_38);
+                        var name_39 = ts.getProperty(renamedCatchVariableDeclarations, String(ts.getOriginalNodeId(declaration)));
+                        if (name_39) {
+                            var clone_6 = ts.getMutableClone(name_39);
                             ts.setSourceMapRange(clone_6, node);
                             ts.setCommentRange(clone_6, node);
                             return clone_6;
@@ -45294,8 +45333,8 @@ var ts;
                         return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent), ts.createIdentifier("default"), node);
                     }
                     else if (ts.isImportSpecifier(importDeclaration)) {
-                        var name_39 = importDeclaration.propertyName || importDeclaration.name;
-                        return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent.parent.parent), ts.getSynthesizedClone(name_39), node);
+                        var name_40 = importDeclaration.propertyName || importDeclaration.name;
+                        return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent.parent.parent), ts.getSynthesizedClone(name_40), node);
                     }
                 }
             }
@@ -46906,9 +46945,9 @@ var ts;
             var count = 0;
             while (true) {
                 count++;
-                var name_40 = baseName + "_" + count;
-                if (!(name_40 in currentIdentifiers)) {
-                    return name_40;
+                var name_41 = baseName + "_" + count;
+                if (!(name_41 in currentIdentifiers)) {
+                    return name_41;
                 }
             }
         }
@@ -47797,6 +47836,10 @@ var ts;
                         return symbolAccessibilityResult.errorModuleName ?
                             ts.Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
                             ts.Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_private_name_1;
+                    case 155:
+                        return symbolAccessibilityResult.errorModuleName ?
+                            ts.Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
+                            ts.Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1;
                     case 149:
                     case 148:
                         if (ts.hasModifier(node.parent, 32)) {
@@ -50404,21 +50447,21 @@ var ts;
         }
         function makeTempVariableName(flags) {
             if (flags && !(tempFlags & flags)) {
-                var name_41 = flags === 268435456 ? "_i" : "_n";
-                if (isUniqueName(name_41)) {
+                var name_42 = flags === 268435456 ? "_i" : "_n";
+                if (isUniqueName(name_42)) {
                     tempFlags |= flags;
-                    return name_41;
+                    return name_42;
                 }
             }
             while (true) {
                 var count = tempFlags & 268435455;
                 tempFlags++;
                 if (count !== 8 && count !== 13) {
-                    var name_42 = count < 26
+                    var name_43 = count < 26
                         ? "_" + String.fromCharCode(97 + count)
                         : "_" + (count - 26);
-                    if (isUniqueName(name_42)) {
-                        return name_42;
+                    if (isUniqueName(name_43)) {
+                        return name_43;
                     }
                 }
             }
@@ -50754,10 +50797,10 @@ var ts;
         var resolutions = [];
         var cache = ts.createMap();
         for (var _i = 0, names_1 = names; _i < names_1.length; _i++) {
-            var name_43 = names_1[_i];
-            var result = name_43 in cache
-                ? cache[name_43]
-                : cache[name_43] = loader(name_43, containingFile);
+            var name_44 = names_1[_i];
+            var result = name_44 in cache
+                ? cache[name_44]
+                : cache[name_44] = loader(name_44, containingFile);
             resolutions.push(result);
         }
         return resolutions;
@@ -54447,13 +54490,13 @@ var ts;
             function getJavaScriptCompletionEntries(sourceFile, position, uniqueNames) {
                 var entries = [];
                 var nameTable = ts.getNameTable(sourceFile);
-                for (var name_44 in nameTable) {
-                    if (nameTable[name_44] === position) {
+                for (var name_45 in nameTable) {
+                    if (nameTable[name_45] === position) {
                         continue;
                     }
-                    if (!uniqueNames[name_44]) {
-                        uniqueNames[name_44] = name_44;
-                        var displayName = getCompletionEntryDisplayName(ts.unescapeIdentifier(name_44), compilerOptions.target, true);
+                    if (!uniqueNames[name_45]) {
+                        uniqueNames[name_45] = name_45;
+                        var displayName = getCompletionEntryDisplayName(ts.unescapeIdentifier(name_45), compilerOptions.target, true);
                         if (displayName) {
                             var entry = {
                                 name: displayName,
@@ -55526,8 +55569,8 @@ var ts;
                     if (element.getStart() <= position && position <= element.getEnd()) {
                         continue;
                     }
-                    var name_45 = element.propertyName || element.name;
-                    existingImportsOrExports[name_45.text] = true;
+                    var name_46 = element.propertyName || element.name;
+                    existingImportsOrExports[name_46.text] = true;
                 }
                 if (!ts.someProperties(existingImportsOrExports)) {
                     return ts.filter(exportsOfModule, function (e) { return e.name !== "default"; });
@@ -57662,10 +57705,10 @@ var ts;
                     return;
                 }
                 var nameToDeclarations = sourceFile.getNamedDeclarations();
-                for (var name_46 in nameToDeclarations) {
-                    var declarations = nameToDeclarations[name_46];
+                for (var name_47 in nameToDeclarations) {
+                    var declarations = nameToDeclarations[name_47];
                     if (declarations) {
-                        var matches = patternMatcher.getMatchesForLastSegmentOfPattern(name_46);
+                        var matches = patternMatcher.getMatchesForLastSegmentOfPattern(name_47);
                         if (!matches) {
                             continue;
                         }
@@ -57676,14 +57719,14 @@ var ts;
                                 if (!containers) {
                                     return undefined;
                                 }
-                                matches = patternMatcher.getMatches(containers, name_46);
+                                matches = patternMatcher.getMatches(containers, name_47);
                                 if (!matches) {
                                     continue;
                                 }
                             }
                             var fileName = sourceFile.fileName;
                             var matchKind = bestMatchKind(matches);
-                            rawItems.push({ name: name_46, fileName: fileName, matchKind: matchKind, isCaseSensitive: allMatchesAreCaseSensitive(matches), declaration: declaration });
+                            rawItems.push({ name: name_47, fileName: fileName, matchKind: matchKind, isCaseSensitive: allMatchesAreCaseSensitive(matches), declaration: declaration });
                         }
                     }
                 }
@@ -57936,9 +57979,9 @@ var ts;
                 case 174:
                 case 223:
                     var decl = node;
-                    var name_47 = decl.name;
-                    if (ts.isBindingPattern(name_47)) {
-                        addChildrenRecursively(name_47);
+                    var name_48 = decl.name;
+                    if (ts.isBindingPattern(name_48)) {
+                        addChildrenRecursively(name_48);
                     }
                     else if (decl.initializer && isFunctionOrClassExpression(decl.initializer)) {
                         addChildrenRecursively(decl.initializer);
@@ -60728,9 +60771,9 @@ var ts;
             }
             Rules.prototype.getRuleName = function (rule) {
                 var o = this;
-                for (var name_48 in o) {
-                    if (o[name_48] === rule) {
-                        return name_48;
+                for (var name_49 in o) {
+                    if (o[name_49] === rule) {
+                        return name_49;
                     }
                 }
                 throw new Error("Unknown rule");
@@ -64215,15 +64258,15 @@ var ts;
                 var compilerOptions = this.getCompilationSettings();
                 var lastDeletedFileName = this.project.projectService.lastDeletedFile && this.project.projectService.lastDeletedFile.fileName;
                 for (var _i = 0, names_2 = names; _i < names_2.length; _i++) {
-                    var name_49 = names_2[_i];
-                    var resolution = newResolutions[name_49];
+                    var name_50 = names_2[_i];
+                    var resolution = newResolutions[name_50];
                     if (!resolution) {
-                        var existingResolution = currentResolutionsInFile && currentResolutionsInFile[name_49];
+                        var existingResolution = currentResolutionsInFile && currentResolutionsInFile[name_50];
                         if (moduleResolutionIsValid(existingResolution)) {
                             resolution = existingResolution;
                         }
                         else {
-                            newResolutions[name_49] = resolution = loader(name_49, containingFile, compilerOptions, this);
+                            newResolutions[name_50] = resolution = loader(name_50, containingFile, compilerOptions, this);
                         }
                         if (logChanges && this.filesWithChangedSetOfUnresolvedImports && !resolutionIsEqualTo(existingResolution, resolution)) {
                             this.filesWithChangedSetOfUnresolvedImports.push(path);
@@ -64951,9 +64994,7 @@ var ts;
                 else if (hasExplicitListOfFiles) {
                     this.compilerOptions.allowNonTsExtensions = true;
                 }
-                if (this.projectKind === ProjectKind.Inferred || this.projectKind === ProjectKind.External) {
-                    this.compilerOptions.noEmitForJsFiles = true;
-                }
+                this.setInternalCompilerOptionsForEmittingJsFiles();
                 this.lsHost = new server.LSHost(this.projectService.host, this, this.projectService.cancellationToken);
                 this.lsHost.setCompilationSettings(this.compilerOptions);
                 this.languageService = ts.createLanguageService(this.lsHost, this.documentRegistry);
@@ -64975,6 +65016,11 @@ var ts;
             Project.prototype.getCachedUnresolvedImportsPerFile_TestOnly = function () {
                 return this.cachedUnresolvedImportsPerFile;
             };
+            Project.prototype.setInternalCompilerOptionsForEmittingJsFiles = function () {
+                if (this.projectKind === ProjectKind.Inferred || this.projectKind === ProjectKind.External) {
+                    this.compilerOptions.noEmitForJsFiles = true;
+                }
+            };
             Project.prototype.getProjectErrors = function () {
                 return this.projectErrors;
             };
@@ -65172,9 +65218,9 @@ var ts;
                 }
                 var unresolvedImports;
                 if (file.resolvedModules) {
-                    for (var name_50 in file.resolvedModules) {
-                        if (!file.resolvedModules[name_50] && !ts.isExternalModuleNameRelative(name_50)) {
-                            var trimmed = name_50.trim();
+                    for (var name_51 in file.resolvedModules) {
+                        if (!file.resolvedModules[name_51] && !ts.isExternalModuleNameRelative(name_51)) {
+                            var trimmed = name_51.trim();
                             var i = trimmed.indexOf("/");
                             if (i !== -1 && trimmed.charCodeAt(0) === 64) {
                                 i = trimmed.indexOf("/", i + 1);
@@ -65288,6 +65334,7 @@ var ts;
                         this.lastCachedUnresolvedImportsList = undefined;
                     }
                     this.compilerOptions = compilerOptions;
+                    this.setInternalCompilerOptionsForEmittingJsFiles();
                     this.lsHost.setCompilationSettings(compilerOptions);
                     this.markAsDirty();
                 }
@@ -67713,9 +67760,9 @@ var ts;
                 if (simplifiedResult) {
                     return completions.entries.reduce(function (result, entry) {
                         if (completions.isMemberCompletion || (entry.name.toLowerCase().indexOf(prefix.toLowerCase()) === 0)) {
-                            var name_51 = entry.name, kind = entry.kind, kindModifiers = entry.kindModifiers, sortText = entry.sortText, replacementSpan = entry.replacementSpan;
+                            var name_52 = entry.name, kind = entry.kind, kindModifiers = entry.kindModifiers, sortText = entry.sortText, replacementSpan = entry.replacementSpan;
                             var convertedSpan = replacementSpan ? _this.decorateSpan(replacementSpan, scriptInfo) : undefined;
-                            result.push({ name: name_51, kind: kind, kindModifiers: kindModifiers, sortText: sortText, replacementSpan: convertedSpan });
+                            result.push({ name: name_52, kind: kind, kindModifiers: kindModifiers, sortText: sortText, replacementSpan: convertedSpan });
                         }
                         return result;
                     }, []).sort(function (a, b) { return ts.compareStrings(a.name, b.name); });
diff --git a/lib/tsserverlibrary.d.ts b/lib/tsserverlibrary.d.ts
index a93576fd993..bf014f3242b 100644
--- a/lib/tsserverlibrary.d.ts
+++ b/lib/tsserverlibrary.d.ts
@@ -1230,26 +1230,20 @@ declare namespace ts {
         HasImplicitReturn = 128,
         HasExplicitReturn = 256,
         GlobalAugmentation = 512,
-        HasClassExtends = 1024,
-        HasDecorators = 2048,
-        HasParamDecorators = 4096,
-        HasAsyncFunctions = 8192,
-        HasSpreadAttribute = 16384,
-        HasRestAttribute = 32768,
-        DisallowInContext = 65536,
-        YieldContext = 131072,
-        DecoratorContext = 262144,
-        AwaitContext = 524288,
-        ThisNodeHasError = 1048576,
-        JavaScriptFile = 2097152,
-        ThisNodeOrAnySubNodesHasError = 4194304,
-        HasAggregatedChildData = 8388608,
+        HasAsyncFunctions = 1024,
+        DisallowInContext = 2048,
+        YieldContext = 4096,
+        DecoratorContext = 8192,
+        AwaitContext = 16384,
+        ThisNodeHasError = 32768,
+        JavaScriptFile = 65536,
+        ThisNodeOrAnySubNodesHasError = 131072,
+        HasAggregatedChildData = 262144,
         BlockScoped = 3,
         ReachabilityCheckFlags = 384,
-        EmitHelperFlags = 64512,
-        ReachabilityAndEmitFlags = 64896,
-        ContextFlags = 3080192,
-        TypeExcludesFlags = 655360,
+        ReachabilityAndEmitFlags = 1408,
+        ContextFlags = 96256,
+        TypeExcludesFlags = 20480,
     }
     const enum ModifierFlags {
         None = 0,
@@ -3491,6 +3485,18 @@ declare namespace ts {
         readonly text: string;
         readonly priority?: number;
     }
+    const enum ExternalEmitHelpers {
+        Extends = 1,
+        Assign = 2,
+        Rest = 4,
+        Decorate = 8,
+        Metadata = 16,
+        Param = 32,
+        Awaiter = 64,
+        Generator = 128,
+        FirstEmitHelper = 1,
+        LastEmitHelper = 128,
+    }
     const enum EmitContext {
         SourceFile = 0,
         Expression = 1,
@@ -3563,7 +3569,7 @@ declare namespace ts.performance {
     function disable(): void;
 }
 declare namespace ts {
-    const version = "2.1.3";
+    const version = "2.1.4";
 }
 declare namespace ts {
     const enum Ternary {
@@ -5358,6 +5364,12 @@ declare namespace ts {
             key: string;
             message: string;
         };
+        This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1: {
+            code: number;
+            category: DiagnosticCategory;
+            key: string;
+            message: string;
+        };
         Type_0_does_not_satisfy_the_constraint_1: {
             code: number;
             category: DiagnosticCategory;
@@ -5418,6 +5430,12 @@ declare namespace ts {
             key: string;
             message: string;
         };
+        This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found: {
+            code: number;
+            category: DiagnosticCategory;
+            key: string;
+            message: string;
+        };
         A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value: {
             code: number;
             category: DiagnosticCategory;
@@ -7254,6 +7272,18 @@ declare namespace ts {
             key: string;
             message: string;
         };
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2: {
+            code: number;
+            category: DiagnosticCategory;
+            key: string;
+            message: string;
+        };
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1: {
+            code: number;
+            category: DiagnosticCategory;
+            key: string;
+            message: string;
+        };
         The_current_host_does_not_support_the_0_option: {
             code: number;
             category: DiagnosticCategory;
@@ -8913,6 +8943,7 @@ declare namespace ts {
     function isBlockScopedContainerTopLevel(node: Node): boolean;
     function isGlobalScopeAugmentation(module: ModuleDeclaration): boolean;
     function isExternalModuleAugmentation(node: Node): boolean;
+    function isEffectiveExternalModule(node: SourceFile, compilerOptions: CompilerOptions): boolean;
     function isBlockScope(node: Node, parentNode: Node): boolean;
     function getEnclosingBlockScopeContainer(node: Node): Node;
     function declarationNameToString(name: DeclarationName): string;
@@ -11106,6 +11137,7 @@ declare namespace ts.server {
         isJsOnlyProject(): boolean;
         getCachedUnresolvedImportsPerFile_TestOnly(): UnresolvedImportsMap;
         constructor(projectName: string, projectKind: ProjectKind, projectService: ProjectService, documentRegistry: ts.DocumentRegistry, hasExplicitListOfFiles: boolean, languageServiceEnabled: boolean, compilerOptions: CompilerOptions, compileOnSaveEnabled: boolean);
+        private setInternalCompilerOptionsForEmittingJsFiles();
         getProjectErrors(): Diagnostic[];
         getLanguageService(ensureSynchronized?: boolean): LanguageService;
         getCompileOnSaveAffectedFileList(scriptInfo: ScriptInfo): string[];
diff --git a/lib/tsserverlibrary.js b/lib/tsserverlibrary.js
index af13c561eeb..439d1d4d07e 100644
--- a/lib/tsserverlibrary.js
+++ b/lib/tsserverlibrary.js
@@ -137,7 +137,7 @@ var ts;
 })(ts || (ts = {}));
 var ts;
 (function (ts) {
-    ts.version = "2.1.3";
+    ts.version = "2.1.4";
 })(ts || (ts = {}));
 (function (ts) {
     var createObject = Object.create;
@@ -2673,6 +2673,7 @@ var ts;
         Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword: { code: 2340, category: ts.DiagnosticCategory.Error, key: "Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword_2340", message: "Only public and protected methods of the base class are accessible via the 'super' keyword." },
         Property_0_is_private_and_only_accessible_within_class_1: { code: 2341, category: ts.DiagnosticCategory.Error, key: "Property_0_is_private_and_only_accessible_within_class_1_2341", message: "Property '{0}' is private and only accessible within class '{1}'." },
         An_index_expression_argument_must_be_of_type_string_number_symbol_or_any: { code: 2342, category: ts.DiagnosticCategory.Error, key: "An_index_expression_argument_must_be_of_type_string_number_symbol_or_any_2342", message: "An index expression argument must be of type 'string', 'number', 'symbol', or 'any'." },
+        This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1: { code: 2343, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1_2343", message: "This syntax requires an imported helper named '{1}', but module '{0}' has no exported member '{1}'." },
         Type_0_does_not_satisfy_the_constraint_1: { code: 2344, category: ts.DiagnosticCategory.Error, key: "Type_0_does_not_satisfy_the_constraint_1_2344", message: "Type '{0}' does not satisfy the constraint '{1}'." },
         Argument_of_type_0_is_not_assignable_to_parameter_of_type_1: { code: 2345, category: ts.DiagnosticCategory.Error, key: "Argument_of_type_0_is_not_assignable_to_parameter_of_type_1_2345", message: "Argument of type '{0}' is not assignable to parameter of type '{1}'." },
         Supplied_parameters_do_not_match_any_signature_of_call_target: { code: 2346, category: ts.DiagnosticCategory.Error, key: "Supplied_parameters_do_not_match_any_signature_of_call_target_2346", message: "Supplied parameters do not match any signature of call target." },
@@ -2683,6 +2684,7 @@ var ts;
         Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature: { code: 2351, category: ts.DiagnosticCategory.Error, key: "Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature_2351", message: "Cannot use 'new' with an expression whose type lacks a call or construct signature." },
         Type_0_cannot_be_converted_to_type_1: { code: 2352, category: ts.DiagnosticCategory.Error, key: "Type_0_cannot_be_converted_to_type_1_2352", message: "Type '{0}' cannot be converted to type '{1}'." },
         Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1: { code: 2353, category: ts.DiagnosticCategory.Error, key: "Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1_2353", message: "Object literal may only specify known properties, and '{0}' does not exist in type '{1}'." },
+        This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found: { code: 2354, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found_2354", message: "This syntax requires an imported helper but module '{0}' cannot be found." },
         A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value: { code: 2355, category: ts.DiagnosticCategory.Error, key: "A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value_2355", message: "A function whose declared type is neither 'void' nor 'any' must return a value." },
         An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type: { code: 2356, category: ts.DiagnosticCategory.Error, key: "An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type_2356", message: "An arithmetic operand must be of type 'any', 'number' or an enum type." },
         The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access: { code: 2357, category: ts.DiagnosticCategory.Error, key: "The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access_2357", message: "The operand of an increment or decrement operator must be a variable or a property access." },
@@ -2989,6 +2991,8 @@ var ts;
         Default_export_of_the_module_has_or_is_using_private_name_0: { code: 4082, category: ts.DiagnosticCategory.Error, key: "Default_export_of_the_module_has_or_is_using_private_name_0_4082", message: "Default export of the module has or is using private name '{0}'." },
         Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1: { code: 4083, category: ts.DiagnosticCategory.Error, key: "Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1_4083", message: "Type parameter '{0}' of exported type alias has or is using private name '{1}'." },
         Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_library_to_resolve_the_conflict: { code: 4090, category: ts.DiagnosticCategory.Message, key: "Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_librar_4090", message: "Conflicting definitions for '{0}' found at '{1}' and '{2}'. Consider installing a specific version of this library to resolve the conflict." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2: { code: 4091, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2_4091", message: "Parameter '{0}' of index signature from exported interface has or is using name '{1}' from private module '{2}'." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1: { code: 4092, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1_4092", message: "Parameter '{0}' of index signature from exported interface has or is using private name '{1}'." },
         The_current_host_does_not_support_the_0_option: { code: 5001, category: ts.DiagnosticCategory.Error, key: "The_current_host_does_not_support_the_0_option_5001", message: "The current host does not support the '{0}' option." },
         Cannot_find_the_common_subdirectory_path_for_the_input_files: { code: 5009, category: ts.DiagnosticCategory.Error, key: "Cannot_find_the_common_subdirectory_path_for_the_input_files_5009", message: "Cannot find the common subdirectory path for the input files." },
         File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0: { code: 5010, category: ts.DiagnosticCategory.Error, key: "File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0_5010", message: "File specification cannot end in a recursive directory wildcard ('**'): '{0}'." },
@@ -6965,17 +6969,17 @@ var ts;
     ts.hasChangesInResolutions = hasChangesInResolutions;
     function containsParseError(node) {
         aggregateChildData(node);
-        return (node.flags & 4194304) !== 0;
+        return (node.flags & 131072) !== 0;
     }
     ts.containsParseError = containsParseError;
     function aggregateChildData(node) {
-        if (!(node.flags & 8388608)) {
-            var thisNodeOrAnySubNodesHasError = ((node.flags & 1048576) !== 0) ||
+        if (!(node.flags & 262144)) {
+            var thisNodeOrAnySubNodesHasError = ((node.flags & 32768) !== 0) ||
                 ts.forEachChild(node, containsParseError);
             if (thisNodeOrAnySubNodesHasError) {
-                node.flags |= 4194304;
+                node.flags |= 131072;
             }
-            node.flags |= 8388608;
+            node.flags |= 262144;
         }
     }
     function getSourceFileOfNode(node) {
@@ -7199,6 +7203,10 @@ var ts;
         return false;
     }
     ts.isExternalModuleAugmentation = isExternalModuleAugmentation;
+    function isEffectiveExternalModule(node, compilerOptions) {
+        return ts.isExternalModule(node) || compilerOptions.isolatedModules;
+    }
+    ts.isEffectiveExternalModule = isEffectiveExternalModule;
     function isBlockScope(node, parentNode) {
         switch (node.kind) {
             case 261:
@@ -7954,7 +7962,7 @@ var ts;
     }
     ts.isSourceFileJavaScript = isSourceFileJavaScript;
     function isInJavaScriptFile(node) {
-        return node && !!(node.flags & 2097152);
+        return node && !!(node.flags & 65536);
     }
     ts.isInJavaScriptFile = isInJavaScriptFile;
     function isRequireCall(expression, checkArgumentIsStringLiteral) {
@@ -8193,7 +8201,7 @@ var ts;
     }
     ts.hasDeclaredRestParameter = hasDeclaredRestParameter;
     function isRestParameter(node) {
-        if (node && (node.flags & 2097152)) {
+        if (node && (node.flags & 65536)) {
             if (node.type && node.type.kind === 275 ||
                 ts.forEach(getJSDocParameterTags(node), function (t) { return t.typeExpression && t.typeExpression.type.kind === 275; })) {
                 return true;
@@ -13732,7 +13740,7 @@ var ts;
     var Parser;
     (function (Parser) {
         var scanner = ts.createScanner(5, true);
-        var disallowInAndDecoratorContext = 65536 | 262144;
+        var disallowInAndDecoratorContext = 2048 | 8192;
         var NodeConstructor;
         var TokenConstructor;
         var IdentifierConstructor;
@@ -13780,7 +13788,7 @@ var ts;
             identifiers = ts.createMap();
             identifierCount = 0;
             nodeCount = 0;
-            contextFlags = scriptKind === 1 || scriptKind === 2 ? 2097152 : 0;
+            contextFlags = scriptKind === 1 || scriptKind === 2 ? 65536 : 0;
             parseErrorBeforeNextFinishedNode = false;
             scanner.setText(sourceText);
             scanner.setOnError(scanError);
@@ -13875,16 +13883,16 @@ var ts;
             }
         }
         function setDisallowInContext(val) {
-            setContextFlag(val, 65536);
+            setContextFlag(val, 2048);
         }
         function setYieldContext(val) {
-            setContextFlag(val, 131072);
+            setContextFlag(val, 4096);
         }
         function setDecoratorContext(val) {
-            setContextFlag(val, 262144);
+            setContextFlag(val, 8192);
         }
         function setAwaitContext(val) {
-            setContextFlag(val, 524288);
+            setContextFlag(val, 16384);
         }
         function doOutsideOfContext(context, func) {
             var contextFlagsToClear = context & contextFlags;
@@ -13907,40 +13915,40 @@ var ts;
             return func();
         }
         function allowInAnd(func) {
-            return doOutsideOfContext(65536, func);
+            return doOutsideOfContext(2048, func);
         }
         function disallowInAnd(func) {
-            return doInsideOfContext(65536, func);
+            return doInsideOfContext(2048, func);
         }
         function doInYieldContext(func) {
-            return doInsideOfContext(131072, func);
+            return doInsideOfContext(4096, func);
         }
         function doInDecoratorContext(func) {
-            return doInsideOfContext(262144, func);
+            return doInsideOfContext(8192, func);
         }
         function doInAwaitContext(func) {
-            return doInsideOfContext(524288, func);
+            return doInsideOfContext(16384, func);
         }
         function doOutsideOfAwaitContext(func) {
-            return doOutsideOfContext(524288, func);
+            return doOutsideOfContext(16384, func);
         }
         function doInYieldAndAwaitContext(func) {
-            return doInsideOfContext(131072 | 524288, func);
+            return doInsideOfContext(4096 | 16384, func);
         }
         function inContext(flags) {
             return (contextFlags & flags) !== 0;
         }
         function inYieldContext() {
-            return inContext(131072);
+            return inContext(4096);
         }
         function inDisallowInContext() {
-            return inContext(65536);
+            return inContext(2048);
         }
         function inDecoratorContext() {
-            return inContext(262144);
+            return inContext(8192);
         }
         function inAwaitContext() {
-            return inContext(524288);
+            return inContext(16384);
         }
         function parseErrorAtCurrentToken(message, arg0) {
             var start = scanner.getTokenPos();
@@ -14102,7 +14110,7 @@ var ts;
             }
             if (parseErrorBeforeNextFinishedNode) {
                 parseErrorBeforeNextFinishedNode = false;
-                node.flags |= 1048576;
+                node.flags |= 32768;
             }
             return node;
         }
@@ -14420,7 +14428,7 @@ var ts;
             if (ts.containsParseError(node)) {
                 return undefined;
             }
-            var nodeContextFlags = node.flags & 3080192;
+            var nodeContextFlags = node.flags & 96256;
             if (nodeContextFlags !== contextFlags) {
                 return undefined;
             }
@@ -15228,7 +15236,7 @@ var ts;
             }
         }
         function parseType() {
-            return doOutsideOfContext(655360, parseTypeWorker);
+            return doOutsideOfContext(20480, parseTypeWorker);
         }
         function parseTypeWorker() {
             if (isStartOfFunctionType()) {
@@ -16859,7 +16867,7 @@ var ts;
             property.type = parseTypeAnnotation();
             property.initializer = ts.hasModifier(property, 32)
                 ? allowInAnd(parseNonParameterInitializer)
-                : doOutsideOfContext(131072 | 65536, parseNonParameterInitializer);
+                : doOutsideOfContext(4096 | 2048, parseNonParameterInitializer);
             parseSemicolon();
             return addJSDocComment(finishNode(property));
         }
@@ -18833,7 +18841,7 @@ var ts;
                 activeLabels = undefined;
                 hasExplicitReturn = false;
                 bindChildren(node);
-                node.flags &= ~64896;
+                node.flags &= ~1408;
                 if (!(currentFlow.flags & 1) && containerFlags & 8 && ts.nodeIsPresent(node.body)) {
                     node.flags |= 128;
                     if (hasExplicitReturn)
@@ -20016,9 +20024,6 @@ var ts;
                     return bindParameter(node);
                 case 223:
                 case 174:
-                    if (node.dotDotDotToken && node.parent.kind === 172) {
-                        emitFlags |= 32768;
-                    }
                     return bindVariableDeclarationOrBindingElement(node);
                 case 147:
                 case 146:
@@ -20045,7 +20050,6 @@ var ts;
                         }
                         root = root.parent;
                     }
-                    emitFlags |= hasRest ? 32768 : 16384;
                     return;
                 case 153:
                 case 154:
@@ -20241,14 +20245,6 @@ var ts;
             }
         }
         function bindClassLikeDeclaration(node) {
-            if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
-                if (ts.getClassExtendsHeritageClauseElement(node) !== undefined) {
-                    emitFlags |= 1024;
-                }
-                if (ts.nodeIsDecorated(node)) {
-                    emitFlags |= 2048;
-                }
-            }
             if (node.kind === 226) {
                 bindBlockScopedDeclaration(node, 32, 899519);
             }
@@ -20292,11 +20288,6 @@ var ts;
             }
         }
         function bindParameter(node) {
-            if (!ts.isDeclarationFile(file) &&
-                !ts.isInAmbientContext(node) &&
-                ts.nodeIsDecorated(node)) {
-                emitFlags |= (2048 | 4096);
-            }
             if (inStrictMode) {
                 checkStrictModeEvalOrArguments(node, node.name);
             }
@@ -20314,7 +20305,7 @@ var ts;
         function bindFunctionDeclaration(node) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192;
+                    emitFlags |= 1024;
                 }
             }
             checkStrictModeFunctionName(node);
@@ -20329,7 +20320,7 @@ var ts;
         function bindFunctionExpression(node) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192;
+                    emitFlags |= 1024;
                 }
             }
             if (currentFlow) {
@@ -20342,10 +20333,7 @@ var ts;
         function bindPropertyOrMethodOrAccessor(node, symbolFlags, symbolExcludes) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192;
-                }
-                if (ts.nodeIsDecorated(node)) {
-                    emitFlags |= 2048;
+                    emitFlags |= 1024;
                 }
             }
             if (currentFlow && ts.isObjectLiteralOrClassExpressionMethod(node)) {
@@ -21053,6 +21041,8 @@ var ts;
     ts.getSymbolId = getSymbolId;
     function createTypeChecker(host, produceDiagnostics) {
         var cancellationToken;
+        var requestedExternalEmitHelpers;
+        var externalHelpersModule;
         var Symbol = ts.objectAllocator.getSymbolConstructor();
         var Type = ts.objectAllocator.getTypeConstructor();
         var Signature = ts.objectAllocator.getSignatureConstructor();
@@ -23381,7 +23371,13 @@ var ts;
             return name.kind === 142 && !ts.isStringOrNumericLiteral(name.expression);
         }
         function getRestType(source, properties, symbol) {
-            ts.Debug.assert(!!(source.flags & 32768), "Rest types only support object types right now.");
+            source = filterType(source, function (t) { return !(t.flags & 6144); });
+            if (source.flags & 8192) {
+                return emptyObjectType;
+            }
+            if (source.flags & 65536) {
+                return mapType(source, function (t) { return getRestType(t, properties, symbol); });
+            }
             var members = ts.createMap();
             var names = ts.createMap();
             for (var _i = 0, properties_2 = properties; _i < properties_2.length; _i++) {
@@ -23417,7 +23413,7 @@ var ts;
             var type;
             if (pattern.kind === 172) {
                 if (declaration.dotDotDotToken) {
-                    if (!(parentType.flags & 32768)) {
+                    if (!isValidSpreadType(parentType)) {
                         error(declaration, ts.Diagnostics.Rest_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
@@ -23495,7 +23491,7 @@ var ts;
             return strictNullChecks && optional ? includeFalsyTypes(type, 2048) : type;
         }
         function getTypeForVariableLikeDeclaration(declaration, includeOptionality) {
-            if (declaration.flags & 2097152) {
+            if (declaration.flags & 65536) {
                 var type = getTypeForVariableLikeDeclarationFromJSDocComment(declaration);
                 if (type && type !== unknownType) {
                     return type;
@@ -23514,7 +23510,7 @@ var ts;
             if (declaration.type) {
                 return addOptionality(getTypeFromTypeNode(declaration.type), declaration.questionToken && includeOptionality);
             }
-            if ((compilerOptions.noImplicitAny || declaration.flags & 2097152) &&
+            if ((compilerOptions.noImplicitAny || declaration.flags & 65536) &&
                 declaration.kind === 223 && !ts.isBindingPattern(declaration.name) &&
                 !(ts.getCombinedModifierFlags(declaration) & 1) && !ts.isInAmbientContext(declaration)) {
                 if (!(ts.getCombinedNodeFlags(declaration) & 2) && (!declaration.initializer || isNullOrUndefined(declaration.initializer))) {
@@ -23575,13 +23571,18 @@ var ts;
         }
         function getTypeFromObjectBindingPattern(pattern, includePatternInType, reportErrors) {
             var members = ts.createMap();
+            var stringIndexInfo;
             var hasComputedProperties = false;
             ts.forEach(pattern.elements, function (e) {
                 var name = e.propertyName || e.name;
-                if (isComputedNonLiteralName(name) || e.dotDotDotToken) {
+                if (isComputedNonLiteralName(name)) {
                     hasComputedProperties = true;
                     return;
                 }
+                if (e.dotDotDotToken) {
+                    stringIndexInfo = createIndexInfo(anyType, false);
+                    return;
+                }
                 var text = ts.getTextOfPropertyName(name);
                 var flags = 4 | 67108864 | (e.initializer ? 536870912 : 0);
                 var symbol = createSymbol(flags, text);
@@ -23589,7 +23590,7 @@ var ts;
                 symbol.bindingElement = e;
                 members[symbol.name] = symbol;
             });
-            var result = createAnonymousType(undefined, members, emptyArray, emptyArray, undefined, undefined);
+            var result = createAnonymousType(undefined, members, emptyArray, emptyArray, stringIndexInfo, undefined);
             if (includePatternInType) {
                 result.pattern = pattern;
             }
@@ -23654,7 +23655,7 @@ var ts;
                 if (declaration.kind === 240) {
                     return links.type = checkExpression(declaration.expression);
                 }
-                if (declaration.flags & 2097152 && declaration.kind === 286 && declaration.typeExpression) {
+                if (declaration.flags & 65536 && declaration.kind === 286 && declaration.typeExpression) {
                     return links.type = getTypeFromTypeNode(declaration.typeExpression.type);
                 }
                 if (!pushTypeResolution(symbol, 0)) {
@@ -23663,7 +23664,7 @@ var ts;
                 var type = void 0;
                 if (declaration.kind === 192 ||
                     declaration.kind === 177 && declaration.parent.kind === 192) {
-                    if (declaration.flags & 2097152) {
+                    if (declaration.flags & 65536) {
                         var jsdocType = ts.getJSDocType(declaration.parent);
                         if (jsdocType) {
                             return links.type = getTypeFromTypeNode(jsdocType);
@@ -23717,7 +23718,7 @@ var ts;
             if (!links.type) {
                 var getter = ts.getDeclarationOfKind(symbol, 151);
                 var setter = ts.getDeclarationOfKind(symbol, 152);
-                if (getter && getter.flags & 2097152) {
+                if (getter && getter.flags & 65536) {
                     var jsDocType = getTypeForVariableLikeDeclarationFromJSDocComment(getter);
                     if (jsDocType) {
                         return links.type = jsDocType;
@@ -24588,7 +24589,7 @@ var ts;
                     var isomorphicProp = isomorphicType && getPropertyOfType(isomorphicType, propName);
                     var isOptional = templateOptional || !!(isomorphicProp && isomorphicProp.flags & 536870912);
                     var prop = createSymbol(4 | 67108864 | (isOptional ? 536870912 : 0), propName);
-                    prop.type = addOptionality(propType, isOptional);
+                    prop.type = propType;
                     prop.isReadonly = templateReadonly || isomorphicProp && isReadonlySymbol(isomorphicProp);
                     members[propName] = prop;
                 }
@@ -24609,7 +24610,7 @@ var ts;
         function getTemplateTypeFromMappedType(type) {
             return type.templateType ||
                 (type.templateType = type.declaration.type ?
-                    instantiateType(getTypeFromTypeNode(type.declaration.type), type.mapper || identityMapper) :
+                    instantiateType(addOptionality(getTypeFromTypeNode(type.declaration.type), !!type.declaration.questionToken), type.mapper || identityMapper) :
                     unknownType);
         }
         function getIsomorphicTypeFromMappedType(type) {
@@ -24858,7 +24859,7 @@ var ts;
             return undefined;
         }
         function getTypeParametersFromJSDocTemplate(declaration) {
-            if (declaration.flags & 2097152) {
+            if (declaration.flags & 65536) {
                 var templateTag = ts.getJSDocTemplateTag(declaration);
                 if (templateTag) {
                     return getTypeParametersFromDeclaration(templateTag.typeParameters);
@@ -24886,7 +24887,7 @@ var ts;
             return result;
         }
         function isJSDocOptionalParameter(node) {
-            if (node.flags & 2097152) {
+            if (node.flags & 65536) {
                 if (node.type && node.type.kind === 273) {
                     return true;
                 }
@@ -25015,7 +25016,7 @@ var ts;
             else if (declaration.type) {
                 return getTypeFromTypeNode(declaration.type);
             }
-            if (declaration.flags & 2097152) {
+            if (declaration.flags & 65536) {
                 var type = getReturnTypeFromJSDocComment(declaration);
                 if (type && type !== unknownType) {
                     return type;
@@ -25822,7 +25823,7 @@ var ts;
             }
             var mapper = createUnaryTypeMapper(getTypeParameterFromMappedType(type), indexType);
             var templateMapper = type.mapper ? combineTypeMappers(type.mapper, mapper) : mapper;
-            return addOptionality(instantiateType(getTemplateTypeFromMappedType(type), templateMapper), !!type.declaration.questionToken);
+            return instantiateType(getTemplateTypeFromMappedType(type), templateMapper);
         }
         function getIndexedAccessType(objectType, indexType, accessNode) {
             if (indexType.flags & 16384 ||
@@ -25898,10 +25899,23 @@ var ts;
             return symbol ? getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol) : undefined;
         }
         function getSpreadType(left, right, isFromObjectLiteral) {
-            ts.Debug.assert(!!(left.flags & (32768 | 1)) && !!(right.flags & (32768 | 1)), "Only object types may be spread.");
             if (left.flags & 1 || right.flags & 1) {
                 return anyType;
             }
+            left = filterType(left, function (t) { return !(t.flags & 6144); });
+            if (left.flags & 8192) {
+                return right;
+            }
+            right = filterType(right, function (t) { return !(t.flags & 6144); });
+            if (right.flags & 8192) {
+                return left;
+            }
+            if (left.flags & 65536) {
+                return mapType(left, function (t) { return getSpreadType(t, right, isFromObjectLiteral); });
+            }
+            if (right.flags & 65536) {
+                return mapType(right, function (t) { return getSpreadType(left, t, isFromObjectLiteral); });
+            }
             var members = ts.createMap();
             var skippedPrivateMembers = ts.createMap();
             var stringIndexInfo;
@@ -27826,6 +27840,8 @@ var ts;
             var typeInferences = createTypeInferencesObject();
             var typeInferencesArray = [typeInferences];
             var templateType = getTemplateTypeFromMappedType(target);
+            var readonlyMask = target.declaration.readonlyToken ? false : true;
+            var optionalMask = target.declaration.questionToken ? 0 : 536870912;
             var properties = getPropertiesOfType(source);
             var members = createSymbolTable(properties);
             var hasInferredTypes = false;
@@ -27833,10 +27849,10 @@ var ts;
                 var prop = properties_4[_i];
                 var inferredPropType = inferTargetType(getTypeOfSymbol(prop));
                 if (inferredPropType) {
-                    var inferredProp = createSymbol(4 | 67108864 | prop.flags & 536870912, prop.name);
+                    var inferredProp = createSymbol(4 | 67108864 | prop.flags & optionalMask, prop.name);
                     inferredProp.declarations = prop.declarations;
                     inferredProp.type = inferredPropType;
-                    inferredProp.isReadonly = isReadonlySymbol(prop);
+                    inferredProp.isReadonly = readonlyMask && isReadonlySymbol(prop);
                     members[prop.name] = inferredProp;
                     hasInferredTypes = true;
                 }
@@ -27845,7 +27861,7 @@ var ts;
             if (indexInfo) {
                 var inferredIndexType = inferTargetType(indexInfo.type);
                 if (inferredIndexType) {
-                    indexInfo = createIndexInfo(inferredIndexType, indexInfo.isReadonly);
+                    indexInfo = createIndexInfo(inferredIndexType, readonlyMask && indexInfo.isReadonly);
                     hasInferredTypes = true;
                 }
             }
@@ -29182,7 +29198,7 @@ var ts;
                         error(node, ts.Diagnostics.The_arguments_object_cannot_be_referenced_in_an_async_function_or_method_in_ES3_and_ES5_Consider_using_a_standard_function_or_method);
                     }
                 }
-                if (node.flags & 524288) {
+                if (node.flags & 16384) {
                     getNodeLinks(container).flags |= 8192;
                 }
                 return getTypeOfSymbol(symbol);
@@ -30095,7 +30111,7 @@ var ts;
                         if (impliedProp) {
                             prop.flags |= impliedProp.flags & 536870912;
                         }
-                        else if (!compilerOptions.suppressExcessPropertyErrors) {
+                        else if (!compilerOptions.suppressExcessPropertyErrors && !getIndexInfoOfType(contextualType, 0)) {
                             error(memberDecl.name, ts.Diagnostics.Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1, symbolToString(member), typeToString(contextualType));
                         }
                     }
@@ -30109,6 +30125,9 @@ var ts;
                     member = prop;
                 }
                 else if (memberDecl.kind === 259) {
+                    if (languageVersion < 5) {
+                        checkExternalEmitHelpers(memberDecl, 2);
+                    }
                     if (propertiesArray.length > 0) {
                         spread = getSpreadType(spread, createObjectLiteralType(), true);
                         propertiesArray = [];
@@ -30118,7 +30137,7 @@ var ts;
                         typeFlags = 0;
                     }
                     var type = checkExpression(memberDecl.expression);
-                    if (!(type.flags & (32768 | 1))) {
+                    if (!isValidSpreadType(type)) {
                         error(memberDecl, ts.Diagnostics.Spread_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
@@ -30183,6 +30202,11 @@ var ts;
                 return result;
             }
         }
+        function isValidSpreadType(type) {
+            return !!(type.flags & (1 | 4096 | 2048) ||
+                type.flags & 32768 && !isGenericMappedType(type) ||
+                type.flags & 196608 && !ts.forEach(type.types, function (t) { return !isValidSpreadType(t); }));
+        }
         function checkJsxSelfClosingElement(node) {
             checkJsxOpeningLikeElement(node);
             return jsxElementType || anyType;
@@ -30257,6 +30281,9 @@ var ts;
             return exprType;
         }
         function checkJsxSpreadAttribute(node, elementAttributesType, nameTable) {
+            if (compilerOptions.jsx === 2) {
+                checkExternalEmitHelpers(node, 2);
+            }
             var type = checkExpression(node.expression);
             var props = getPropertiesOfType(type);
             for (var _i = 0, props_2 = props; _i < props_2.length; _i++) {
@@ -32003,7 +32030,7 @@ var ts;
         }
         function checkAwaitExpression(node) {
             if (produceDiagnostics) {
-                if (!(node.flags & 524288)) {
+                if (!(node.flags & 16384)) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.await_expression_is_only_allowed_within_an_async_function);
                 }
                 if (isInParameterInitializerBeforeContainingFunction(node)) {
@@ -32161,6 +32188,9 @@ var ts;
                 }
             }
             else if (property.kind === 259) {
+                if (languageVersion < 5) {
+                    checkExternalEmitHelpers(property, 4);
+                }
                 var nonRestNames = [];
                 if (allProperties) {
                     for (var i = 0; i < allProperties.length - 1; i++) {
@@ -32511,7 +32541,7 @@ var ts;
         }
         function checkYieldExpression(node) {
             if (produceDiagnostics) {
-                if (!(node.flags & 131072) || isYieldExpressionInClass(node)) {
+                if (!(node.flags & 4096) || isYieldExpressionInClass(node)) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.A_yield_expression_is_only_allowed_in_a_generator_body);
                 }
                 if (isInParameterInitializerBeforeContainingFunction(node)) {
@@ -32887,6 +32917,12 @@ var ts;
                 node.kind === 154) {
                 checkGrammarFunctionLikeDeclaration(node);
             }
+            if (ts.isAsyncFunctionLike(node) && languageVersion < 4) {
+                checkExternalEmitHelpers(node, 64);
+                if (languageVersion < 2) {
+                    checkExternalEmitHelpers(node, 128);
+                }
+            }
             checkTypeParameters(node.typeParameters);
             ts.forEach(node.parameters, checkParameter);
             if (node.type) {
@@ -33681,7 +33717,13 @@ var ts;
             if (!compilerOptions.experimentalDecorators) {
                 error(node, ts.Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning);
             }
+            var firstDecorator = node.decorators[0];
+            checkExternalEmitHelpers(firstDecorator, 8);
+            if (node.kind === 144) {
+                checkExternalEmitHelpers(firstDecorator, 32);
+            }
             if (compilerOptions.emitDecoratorMetadata) {
+                checkExternalEmitHelpers(firstDecorator, 16);
                 switch (node.kind) {
                     case 226:
                         var constructor = ts.getFirstConstructorWithBody(node);
@@ -33998,14 +34040,14 @@ var ts;
             }
         }
         function checkCollisionWithGlobalPromiseInGeneratedCode(node, name) {
-            if (!needCollisionCheckForIdentifier(node, name, "Promise")) {
+            if (languageVersion >= 4 || !needCollisionCheckForIdentifier(node, name, "Promise")) {
                 return;
             }
             if (node.kind === 230 && ts.getModuleInstanceState(node) !== 1) {
                 return;
             }
             var parent = getDeclarationContainer(node);
-            if (parent.kind === 261 && ts.isExternalOrCommonJsModule(parent) && parent.flags & 8192) {
+            if (parent.kind === 261 && ts.isExternalOrCommonJsModule(parent) && parent.flags & 1024) {
                 error(name, ts.Diagnostics.Duplicate_identifier_0_Compiler_reserves_name_1_in_top_level_scope_of_a_module_containing_async_functions, ts.declarationNameToString(name), ts.declarationNameToString(name));
             }
         }
@@ -34102,6 +34144,9 @@ var ts;
                 }
             }
             if (node.kind === 174) {
+                if (node.parent.kind === 172 && languageVersion < 5) {
+                    checkExternalEmitHelpers(node, 4);
+                }
                 if (node.propertyName && node.propertyName.kind === 142) {
                     checkComputedPropertyName(node.propertyName);
                 }
@@ -34511,7 +34556,7 @@ var ts;
         }
         function checkWithStatement(node) {
             if (!checkGrammarStatementInAmbientContext(node)) {
-                if (node.flags & 524288) {
+                if (node.flags & 16384) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.with_statements_are_not_allowed_in_an_async_function_block);
                 }
             }
@@ -34757,6 +34802,9 @@ var ts;
             checkClassForDuplicateDeclarations(node);
             var baseTypeNode = ts.getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
+                if (languageVersion < 2) {
+                    checkExternalEmitHelpers(baseTypeNode.parent, 1);
+                }
                 var baseTypes = getBaseTypes(type);
                 if (baseTypes.length && produceDiagnostics) {
                     var baseType_1 = baseTypes[0];
@@ -36664,8 +36712,6 @@ var ts;
                 ts.bindSourceFile(file, compilerOptions);
             }
             var augmentations;
-            var requestedExternalEmitHelpers = 0;
-            var firstFileRequestingExternalHelpers;
             for (var _b = 0, _c = host.getSourceFiles(); _b < _c.length; _b++) {
                 var file = _c[_b];
                 if (!ts.isExternalOrCommonJsModule(file)) {
@@ -36685,15 +36731,6 @@ var ts;
                         }
                     }
                 }
-                if ((compilerOptions.isolatedModules || ts.isExternalModule(file)) && !file.isDeclarationFile) {
-                    var fileRequestedExternalEmitHelpers = file.flags & 64512;
-                    if (fileRequestedExternalEmitHelpers) {
-                        requestedExternalEmitHelpers |= fileRequestedExternalEmitHelpers;
-                        if (firstFileRequestingExternalHelpers === undefined) {
-                            firstFileRequestingExternalHelpers = file;
-                        }
-                    }
-                }
             }
             if (augmentations) {
                 for (var _d = 0, augmentations_1 = augmentations; _d < augmentations_1.length; _d++) {
@@ -36748,44 +36785,46 @@ var ts;
             var symbol = getGlobalSymbol("ReadonlyArray", 793064, undefined);
             globalReadonlyArrayType = symbol && getTypeOfGlobalSymbol(symbol, 1);
             anyReadonlyArrayType = globalReadonlyArrayType ? createTypeFromGenericGlobalType(globalReadonlyArrayType, [anyType]) : anyArrayType;
-            if (compilerOptions.importHelpers && firstFileRequestingExternalHelpers) {
-                var helpersModule = resolveExternalModule(firstFileRequestingExternalHelpers, ts.externalHelpersModuleNameText, ts.Diagnostics.Cannot_find_module_0, undefined);
-                if (helpersModule) {
-                    var exports_2 = helpersModule.exports;
-                    if (requestedExternalEmitHelpers & 1024 && languageVersion < 2) {
-                        verifyHelperSymbol(exports_2, "__extends", 107455);
-                    }
-                    if (requestedExternalEmitHelpers & 16384 &&
-                        (languageVersion < 5 || compilerOptions.jsx === 2)) {
-                        verifyHelperSymbol(exports_2, "__assign", 107455);
-                    }
-                    if (languageVersion < 5 && requestedExternalEmitHelpers & 32768) {
-                        verifyHelperSymbol(exports_2, "__rest", 107455);
-                    }
-                    if (requestedExternalEmitHelpers & 2048) {
-                        verifyHelperSymbol(exports_2, "__decorate", 107455);
-                        if (compilerOptions.emitDecoratorMetadata) {
-                            verifyHelperSymbol(exports_2, "__metadata", 107455);
-                        }
-                    }
-                    if (requestedExternalEmitHelpers & 4096) {
-                        verifyHelperSymbol(exports_2, "__param", 107455);
-                    }
-                    if (requestedExternalEmitHelpers & 8192) {
-                        verifyHelperSymbol(exports_2, "__awaiter", 107455);
-                        if (languageVersion < 2) {
-                            verifyHelperSymbol(exports_2, "__generator", 107455);
+        }
+        function checkExternalEmitHelpers(location, helpers) {
+            if ((requestedExternalEmitHelpers & helpers) !== helpers && compilerOptions.importHelpers) {
+                var sourceFile = ts.getSourceFileOfNode(location);
+                if (ts.isEffectiveExternalModule(sourceFile, compilerOptions)) {
+                    var helpersModule = resolveHelpersModule(sourceFile, location);
+                    if (helpersModule !== unknownSymbol) {
+                        var uncheckedHelpers = helpers & ~requestedExternalEmitHelpers;
+                        for (var helper = 1; helper <= 128; helper <<= 1) {
+                            if (uncheckedHelpers & helper) {
+                                var name_29 = getHelperName(helper);
+                                var symbol = getSymbol(helpersModule.exports, ts.escapeIdentifier(name_29), 107455);
+                                if (!symbol) {
+                                    error(location, ts.Diagnostics.This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1, ts.externalHelpersModuleNameText, name_29);
+                                }
+                            }
                         }
                     }
+                    requestedExternalEmitHelpers |= helpers;
                 }
             }
         }
-        function verifyHelperSymbol(symbols, name, meaning) {
-            var symbol = getSymbol(symbols, ts.escapeIdentifier(name), meaning);
-            if (!symbol) {
-                error(undefined, ts.Diagnostics.Module_0_has_no_exported_member_1, ts.externalHelpersModuleNameText, name);
+        function getHelperName(helper) {
+            switch (helper) {
+                case 1: return "__extends";
+                case 2: return "__assign";
+                case 4: return "__rest";
+                case 8: return "__decorate";
+                case 16: return "__metadata";
+                case 32: return "__param";
+                case 64: return "__awaiter";
+                case 128: return "__generator";
             }
         }
+        function resolveHelpersModule(node, errorNode) {
+            if (!externalHelpersModule) {
+                externalHelpersModule = resolveExternalModule(node, ts.externalHelpersModuleNameText, ts.Diagnostics.This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found, errorNode) || unknownSymbol;
+            }
+            return externalHelpersModule;
+        }
         function createInstantiatedPromiseLikeType() {
             var promiseLikeType = getGlobalPromiseLikeType();
             if (promiseLikeType !== emptyGenericType) {
@@ -37308,9 +37347,9 @@ var ts;
                 if (prop.kind === 259) {
                     continue;
                 }
-                var name_29 = prop.name;
-                if (name_29.kind === 142) {
-                    checkGrammarComputedPropertyName(name_29);
+                var name_30 = prop.name;
+                if (name_30.kind === 142) {
+                    checkGrammarComputedPropertyName(name_30);
                 }
                 if (prop.kind === 258 && !inDestructuring && prop.objectAssignmentInitializer) {
                     return grammarErrorOnNode(prop.equalsToken, ts.Diagnostics.can_only_be_used_in_an_object_literal_property_inside_a_destructuring_assignment);
@@ -37326,8 +37365,8 @@ var ts;
                 var currentKind = void 0;
                 if (prop.kind === 257 || prop.kind === 258) {
                     checkGrammarForInvalidQuestionMark(prop.questionToken, ts.Diagnostics.An_object_member_cannot_be_declared_optional);
-                    if (name_29.kind === 8) {
-                        checkGrammarNumericLiteral(name_29);
+                    if (name_30.kind === 8) {
+                        checkGrammarNumericLiteral(name_30);
                     }
                     currentKind = Property;
                 }
@@ -37343,7 +37382,7 @@ var ts;
                 else {
                     ts.Debug.fail("Unexpected syntax kind:" + prop.kind);
                 }
-                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_29);
+                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_30);
                 if (effectiveName === undefined) {
                     continue;
                 }
@@ -37353,18 +37392,18 @@ var ts;
                 else {
                     var existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
-                        grammarErrorOnNode(name_29, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_29));
+                        grammarErrorOnNode(name_30, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_30));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
                             seen[effectiveName] = currentKind | existingKind;
                         }
                         else {
-                            return grammarErrorOnNode(name_29, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
+                            return grammarErrorOnNode(name_30, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
                         }
                     }
                     else {
-                        return grammarErrorOnNode(name_29, ts.Diagnostics.An_object_literal_cannot_have_property_and_accessor_with_the_same_name);
+                        return grammarErrorOnNode(name_30, ts.Diagnostics.An_object_literal_cannot_have_property_and_accessor_with_the_same_name);
                     }
                 }
             }
@@ -37377,12 +37416,12 @@ var ts;
                     continue;
                 }
                 var jsxAttr = attr;
-                var name_30 = jsxAttr.name;
-                if (!seen[name_30.text]) {
-                    seen[name_30.text] = true;
+                var name_31 = jsxAttr.name;
+                if (!seen[name_31.text]) {
+                    seen[name_31.text] = true;
                 }
                 else {
-                    return grammarErrorOnNode(name_30, ts.Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
+                    return grammarErrorOnNode(name_31, ts.Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
                 }
                 var initializer = jsxAttr.initializer;
                 if (initializer && initializer.kind === 252 && !initializer.expression) {
@@ -38700,10 +38739,10 @@ var ts;
             }
         }
         for (var _i = 0, pendingDeclarations_1 = pendingDeclarations; _i < pendingDeclarations_1.length; _i++) {
-            var _a = pendingDeclarations_1[_i], pendingExpressions_1 = _a.pendingExpressions, name_31 = _a.name, value = _a.value, location_2 = _a.location, original = _a.original;
-            var variable = ts.createVariableDeclaration(name_31, undefined, pendingExpressions_1 ? ts.inlineExpressions(ts.append(pendingExpressions_1, value)) : value, location_2);
+            var _a = pendingDeclarations_1[_i], pendingExpressions_1 = _a.pendingExpressions, name_32 = _a.name, value = _a.value, location_2 = _a.location, original = _a.original;
+            var variable = ts.createVariableDeclaration(name_32, undefined, pendingExpressions_1 ? ts.inlineExpressions(ts.append(pendingExpressions_1, value)) : value, location_2);
             variable.original = original;
-            if (ts.isIdentifier(name_31)) {
+            if (ts.isIdentifier(name_32)) {
                 ts.setEmitFlags(variable, 64);
             }
             ts.aggregateTransformFlags(variable);
@@ -38849,8 +38888,8 @@ var ts;
             return ts.createElementAccess(value, argumentExpression);
         }
         else {
-            var name_32 = ts.createIdentifier(ts.unescapeIdentifier(propertyName.text));
-            return ts.createPropertyAccess(value, name_32);
+            var name_33 = ts.createIdentifier(ts.unescapeIdentifier(propertyName.text));
+            return ts.createPropertyAccess(value, name_33);
         }
     }
     function ensureIdentifier(flattenContext, value, reuseIdentifierExpressions, location) {
@@ -38892,7 +38931,7 @@ var ts;
     var restHelper = {
         name: "typescript:rest",
         scoped: false,
-        text: "\n            var __rest = (this && this.__rest) || function (s, e) {\n                var t = {};\n                for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)\n                    t[p] = s[p];\n                if (typeof Object.getOwnPropertySymbols === \"function\")\n                    for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)\n                        t[p[i]] = s[p[i]];\n                return t;\n            };"
+        text: "\n            var __rest = (this && this.__rest) || function (s, e) {\n                var t = {};\n                for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)\n                    t[p] = s[p];\n                if (s != null && typeof Object.getOwnPropertySymbols === \"function\")\n                    for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)\n                        t[p[i]] = s[p[i]];\n                return t;\n            };"
     };
     function createRestCall(context, value, elements, computedTempVariables, location) {
         context.requestEmitHelper(restHelper);
@@ -39762,14 +39801,14 @@ var ts;
         function serializeEntityNameAsExpression(node, useFallback) {
             switch (node.kind) {
                 case 70:
-                    var name_33 = ts.getMutableClone(node);
-                    name_33.flags &= ~8;
-                    name_33.original = undefined;
-                    name_33.parent = currentScope;
+                    var name_34 = ts.getMutableClone(node);
+                    name_34.flags &= ~8;
+                    name_34.original = undefined;
+                    name_34.parent = currentScope;
                     if (useFallback) {
-                        return ts.createLogicalAnd(ts.createStrictInequality(ts.createTypeOf(name_33), ts.createLiteral("undefined")), name_33);
+                        return ts.createLogicalAnd(ts.createStrictInequality(ts.createTypeOf(name_34), ts.createLiteral("undefined")), name_34);
                     }
-                    return name_33;
+                    return name_34;
                 case 141:
                     return serializeQualifiedNameAsExpression(node, useFallback);
             }
@@ -39799,7 +39838,7 @@ var ts;
                     : name.expression;
             }
             else if (ts.isIdentifier(name)) {
-                return ts.createLiteral(name.text);
+                return ts.createLiteral(ts.unescapeIdentifier(name.text));
             }
             else {
                 return ts.getSynthesizedClone(name);
@@ -40040,9 +40079,9 @@ var ts;
         }
         function isFirstEmittedDeclarationInScope(node) {
             if (currentScopeFirstDeclarationsOfName) {
-                var name_34 = node.symbol && node.symbol.name;
-                if (name_34) {
-                    return currentScopeFirstDeclarationsOfName[name_34] === node;
+                var name_35 = node.symbol && node.symbol.name;
+                if (name_35) {
+                    return currentScopeFirstDeclarationsOfName[name_35] === node;
                 }
             }
             return false;
@@ -40331,14 +40370,14 @@ var ts;
         }
         function substituteShorthandPropertyAssignment(node) {
             if (enabledSubstitutions & 2) {
-                var name_35 = node.name;
-                var exportedName = trySubstituteNamespaceExportedName(name_35);
+                var name_36 = node.name;
+                var exportedName = trySubstituteNamespaceExportedName(name_36);
                 if (exportedName) {
                     if (node.objectAssignmentInitializer) {
                         var initializer = ts.createAssignment(exportedName, node.objectAssignmentInitializer);
-                        return ts.createPropertyAssignment(name_35, initializer, node);
+                        return ts.createPropertyAssignment(name_36, initializer, node);
                     }
-                    return ts.createPropertyAssignment(name_35, exportedName, node);
+                    return ts.createPropertyAssignment(name_36, exportedName, node);
                 }
             }
             return node;
@@ -40859,12 +40898,12 @@ var ts;
                 return getTagName(node.openingElement);
             }
             else {
-                var name_36 = node.tagName;
-                if (ts.isIdentifier(name_36) && ts.isIntrinsicJsxName(name_36.text)) {
-                    return ts.createLiteral(name_36.text);
+                var name_37 = node.tagName;
+                if (ts.isIdentifier(name_37) && ts.isIntrinsicJsxName(name_37.text)) {
+                    return ts.createLiteral(name_37.text);
                 }
                 else {
-                    return ts.createExpressionFromEntityName(name_36);
+                    return ts.createExpressionFromEntityName(name_37);
                 }
             }
         }
@@ -41997,15 +42036,15 @@ var ts;
             }
             for (var _i = 0, _a = node.parameters; _i < _a.length; _i++) {
                 var parameter = _a[_i];
-                var name_37 = parameter.name, initializer = parameter.initializer, dotDotDotToken = parameter.dotDotDotToken;
+                var name_38 = parameter.name, initializer = parameter.initializer, dotDotDotToken = parameter.dotDotDotToken;
                 if (dotDotDotToken) {
                     continue;
                 }
-                if (ts.isBindingPattern(name_37)) {
-                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name_37, initializer);
+                if (ts.isBindingPattern(name_38)) {
+                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name_38, initializer);
                 }
                 else if (initializer) {
-                    addDefaultValueAssignmentForInitializer(statements, parameter, name_37, initializer);
+                    addDefaultValueAssignmentForInitializer(statements, parameter, name_38, initializer);
                 }
             }
         }
@@ -44010,9 +44049,9 @@ var ts;
                 if (ts.isIdentifier(original) && original.parent) {
                     var declaration = resolver.getReferencedValueDeclaration(original);
                     if (declaration) {
-                        var name_38 = ts.getProperty(renamedCatchVariableDeclarations, String(ts.getOriginalNodeId(declaration)));
-                        if (name_38) {
-                            var clone_6 = ts.getMutableClone(name_38);
+                        var name_39 = ts.getProperty(renamedCatchVariableDeclarations, String(ts.getOriginalNodeId(declaration)));
+                        if (name_39) {
+                            var clone_6 = ts.getMutableClone(name_39);
                             ts.setSourceMapRange(clone_6, node);
                             ts.setCommentRange(clone_6, node);
                             return clone_6;
@@ -45294,8 +45333,8 @@ var ts;
                         return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent), ts.createIdentifier("default"), node);
                     }
                     else if (ts.isImportSpecifier(importDeclaration)) {
-                        var name_39 = importDeclaration.propertyName || importDeclaration.name;
-                        return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent.parent.parent), ts.getSynthesizedClone(name_39), node);
+                        var name_40 = importDeclaration.propertyName || importDeclaration.name;
+                        return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent.parent.parent), ts.getSynthesizedClone(name_40), node);
                     }
                 }
             }
@@ -46906,9 +46945,9 @@ var ts;
             var count = 0;
             while (true) {
                 count++;
-                var name_40 = baseName + "_" + count;
-                if (!(name_40 in currentIdentifiers)) {
-                    return name_40;
+                var name_41 = baseName + "_" + count;
+                if (!(name_41 in currentIdentifiers)) {
+                    return name_41;
                 }
             }
         }
@@ -47797,6 +47836,10 @@ var ts;
                         return symbolAccessibilityResult.errorModuleName ?
                             ts.Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
                             ts.Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_private_name_1;
+                    case 155:
+                        return symbolAccessibilityResult.errorModuleName ?
+                            ts.Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
+                            ts.Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1;
                     case 149:
                     case 148:
                         if (ts.hasModifier(node.parent, 32)) {
@@ -50404,21 +50447,21 @@ var ts;
         }
         function makeTempVariableName(flags) {
             if (flags && !(tempFlags & flags)) {
-                var name_41 = flags === 268435456 ? "_i" : "_n";
-                if (isUniqueName(name_41)) {
+                var name_42 = flags === 268435456 ? "_i" : "_n";
+                if (isUniqueName(name_42)) {
                     tempFlags |= flags;
-                    return name_41;
+                    return name_42;
                 }
             }
             while (true) {
                 var count = tempFlags & 268435455;
                 tempFlags++;
                 if (count !== 8 && count !== 13) {
-                    var name_42 = count < 26
+                    var name_43 = count < 26
                         ? "_" + String.fromCharCode(97 + count)
                         : "_" + (count - 26);
-                    if (isUniqueName(name_42)) {
-                        return name_42;
+                    if (isUniqueName(name_43)) {
+                        return name_43;
                     }
                 }
             }
@@ -50754,10 +50797,10 @@ var ts;
         var resolutions = [];
         var cache = ts.createMap();
         for (var _i = 0, names_1 = names; _i < names_1.length; _i++) {
-            var name_43 = names_1[_i];
-            var result = name_43 in cache
-                ? cache[name_43]
-                : cache[name_43] = loader(name_43, containingFile);
+            var name_44 = names_1[_i];
+            var result = name_44 in cache
+                ? cache[name_44]
+                : cache[name_44] = loader(name_44, containingFile);
             resolutions.push(result);
         }
         return resolutions;
@@ -54447,13 +54490,13 @@ var ts;
             function getJavaScriptCompletionEntries(sourceFile, position, uniqueNames) {
                 var entries = [];
                 var nameTable = ts.getNameTable(sourceFile);
-                for (var name_44 in nameTable) {
-                    if (nameTable[name_44] === position) {
+                for (var name_45 in nameTable) {
+                    if (nameTable[name_45] === position) {
                         continue;
                     }
-                    if (!uniqueNames[name_44]) {
-                        uniqueNames[name_44] = name_44;
-                        var displayName = getCompletionEntryDisplayName(ts.unescapeIdentifier(name_44), compilerOptions.target, true);
+                    if (!uniqueNames[name_45]) {
+                        uniqueNames[name_45] = name_45;
+                        var displayName = getCompletionEntryDisplayName(ts.unescapeIdentifier(name_45), compilerOptions.target, true);
                         if (displayName) {
                             var entry = {
                                 name: displayName,
@@ -55526,8 +55569,8 @@ var ts;
                     if (element.getStart() <= position && position <= element.getEnd()) {
                         continue;
                     }
-                    var name_45 = element.propertyName || element.name;
-                    existingImportsOrExports[name_45.text] = true;
+                    var name_46 = element.propertyName || element.name;
+                    existingImportsOrExports[name_46.text] = true;
                 }
                 if (!ts.someProperties(existingImportsOrExports)) {
                     return ts.filter(exportsOfModule, function (e) { return e.name !== "default"; });
@@ -57662,10 +57705,10 @@ var ts;
                     return;
                 }
                 var nameToDeclarations = sourceFile.getNamedDeclarations();
-                for (var name_46 in nameToDeclarations) {
-                    var declarations = nameToDeclarations[name_46];
+                for (var name_47 in nameToDeclarations) {
+                    var declarations = nameToDeclarations[name_47];
                     if (declarations) {
-                        var matches = patternMatcher.getMatchesForLastSegmentOfPattern(name_46);
+                        var matches = patternMatcher.getMatchesForLastSegmentOfPattern(name_47);
                         if (!matches) {
                             continue;
                         }
@@ -57676,14 +57719,14 @@ var ts;
                                 if (!containers) {
                                     return undefined;
                                 }
-                                matches = patternMatcher.getMatches(containers, name_46);
+                                matches = patternMatcher.getMatches(containers, name_47);
                                 if (!matches) {
                                     continue;
                                 }
                             }
                             var fileName = sourceFile.fileName;
                             var matchKind = bestMatchKind(matches);
-                            rawItems.push({ name: name_46, fileName: fileName, matchKind: matchKind, isCaseSensitive: allMatchesAreCaseSensitive(matches), declaration: declaration });
+                            rawItems.push({ name: name_47, fileName: fileName, matchKind: matchKind, isCaseSensitive: allMatchesAreCaseSensitive(matches), declaration: declaration });
                         }
                     }
                 }
@@ -57936,9 +57979,9 @@ var ts;
                 case 174:
                 case 223:
                     var decl = node;
-                    var name_47 = decl.name;
-                    if (ts.isBindingPattern(name_47)) {
-                        addChildrenRecursively(name_47);
+                    var name_48 = decl.name;
+                    if (ts.isBindingPattern(name_48)) {
+                        addChildrenRecursively(name_48);
                     }
                     else if (decl.initializer && isFunctionOrClassExpression(decl.initializer)) {
                         addChildrenRecursively(decl.initializer);
@@ -60728,9 +60771,9 @@ var ts;
             }
             Rules.prototype.getRuleName = function (rule) {
                 var o = this;
-                for (var name_48 in o) {
-                    if (o[name_48] === rule) {
-                        return name_48;
+                for (var name_49 in o) {
+                    if (o[name_49] === rule) {
+                        return name_49;
                     }
                 }
                 throw new Error("Unknown rule");
@@ -64215,15 +64258,15 @@ var ts;
                 var compilerOptions = this.getCompilationSettings();
                 var lastDeletedFileName = this.project.projectService.lastDeletedFile && this.project.projectService.lastDeletedFile.fileName;
                 for (var _i = 0, names_2 = names; _i < names_2.length; _i++) {
-                    var name_49 = names_2[_i];
-                    var resolution = newResolutions[name_49];
+                    var name_50 = names_2[_i];
+                    var resolution = newResolutions[name_50];
                     if (!resolution) {
-                        var existingResolution = currentResolutionsInFile && currentResolutionsInFile[name_49];
+                        var existingResolution = currentResolutionsInFile && currentResolutionsInFile[name_50];
                         if (moduleResolutionIsValid(existingResolution)) {
                             resolution = existingResolution;
                         }
                         else {
-                            newResolutions[name_49] = resolution = loader(name_49, containingFile, compilerOptions, this);
+                            newResolutions[name_50] = resolution = loader(name_50, containingFile, compilerOptions, this);
                         }
                         if (logChanges && this.filesWithChangedSetOfUnresolvedImports && !resolutionIsEqualTo(existingResolution, resolution)) {
                             this.filesWithChangedSetOfUnresolvedImports.push(path);
@@ -64951,9 +64994,7 @@ var ts;
                 else if (hasExplicitListOfFiles) {
                     this.compilerOptions.allowNonTsExtensions = true;
                 }
-                if (this.projectKind === ProjectKind.Inferred || this.projectKind === ProjectKind.External) {
-                    this.compilerOptions.noEmitForJsFiles = true;
-                }
+                this.setInternalCompilerOptionsForEmittingJsFiles();
                 this.lsHost = new server.LSHost(this.projectService.host, this, this.projectService.cancellationToken);
                 this.lsHost.setCompilationSettings(this.compilerOptions);
                 this.languageService = ts.createLanguageService(this.lsHost, this.documentRegistry);
@@ -64975,6 +65016,11 @@ var ts;
             Project.prototype.getCachedUnresolvedImportsPerFile_TestOnly = function () {
                 return this.cachedUnresolvedImportsPerFile;
             };
+            Project.prototype.setInternalCompilerOptionsForEmittingJsFiles = function () {
+                if (this.projectKind === ProjectKind.Inferred || this.projectKind === ProjectKind.External) {
+                    this.compilerOptions.noEmitForJsFiles = true;
+                }
+            };
             Project.prototype.getProjectErrors = function () {
                 return this.projectErrors;
             };
@@ -65172,9 +65218,9 @@ var ts;
                 }
                 var unresolvedImports;
                 if (file.resolvedModules) {
-                    for (var name_50 in file.resolvedModules) {
-                        if (!file.resolvedModules[name_50] && !ts.isExternalModuleNameRelative(name_50)) {
-                            var trimmed = name_50.trim();
+                    for (var name_51 in file.resolvedModules) {
+                        if (!file.resolvedModules[name_51] && !ts.isExternalModuleNameRelative(name_51)) {
+                            var trimmed = name_51.trim();
                             var i = trimmed.indexOf("/");
                             if (i !== -1 && trimmed.charCodeAt(0) === 64) {
                                 i = trimmed.indexOf("/", i + 1);
@@ -65288,6 +65334,7 @@ var ts;
                         this.lastCachedUnresolvedImportsList = undefined;
                     }
                     this.compilerOptions = compilerOptions;
+                    this.setInternalCompilerOptionsForEmittingJsFiles();
                     this.lsHost.setCompilationSettings(compilerOptions);
                     this.markAsDirty();
                 }
@@ -67713,9 +67760,9 @@ var ts;
                 if (simplifiedResult) {
                     return completions.entries.reduce(function (result, entry) {
                         if (completions.isMemberCompletion || (entry.name.toLowerCase().indexOf(prefix.toLowerCase()) === 0)) {
-                            var name_51 = entry.name, kind = entry.kind, kindModifiers = entry.kindModifiers, sortText = entry.sortText, replacementSpan = entry.replacementSpan;
+                            var name_52 = entry.name, kind = entry.kind, kindModifiers = entry.kindModifiers, sortText = entry.sortText, replacementSpan = entry.replacementSpan;
                             var convertedSpan = replacementSpan ? _this.decorateSpan(replacementSpan, scriptInfo) : undefined;
-                            result.push({ name: name_51, kind: kind, kindModifiers: kindModifiers, sortText: sortText, replacementSpan: convertedSpan });
+                            result.push({ name: name_52, kind: kind, kindModifiers: kindModifiers, sortText: sortText, replacementSpan: convertedSpan });
                         }
                         return result;
                     }, []).sort(function (a, b) { return ts.compareStrings(a.name, b.name); });
diff --git a/lib/typescript.d.ts b/lib/typescript.d.ts
index 4414efb805f..a3a005c12d7 100644
--- a/lib/typescript.d.ts
+++ b/lib/typescript.d.ts
@@ -378,26 +378,20 @@ declare namespace ts {
         HasImplicitReturn = 128,
         HasExplicitReturn = 256,
         GlobalAugmentation = 512,
-        HasClassExtends = 1024,
-        HasDecorators = 2048,
-        HasParamDecorators = 4096,
-        HasAsyncFunctions = 8192,
-        HasSpreadAttribute = 16384,
-        HasRestAttribute = 32768,
-        DisallowInContext = 65536,
-        YieldContext = 131072,
-        DecoratorContext = 262144,
-        AwaitContext = 524288,
-        ThisNodeHasError = 1048576,
-        JavaScriptFile = 2097152,
-        ThisNodeOrAnySubNodesHasError = 4194304,
-        HasAggregatedChildData = 8388608,
+        HasAsyncFunctions = 1024,
+        DisallowInContext = 2048,
+        YieldContext = 4096,
+        DecoratorContext = 8192,
+        AwaitContext = 16384,
+        ThisNodeHasError = 32768,
+        JavaScriptFile = 65536,
+        ThisNodeOrAnySubNodesHasError = 131072,
+        HasAggregatedChildData = 262144,
         BlockScoped = 3,
         ReachabilityCheckFlags = 384,
-        EmitHelperFlags = 64512,
-        ReachabilityAndEmitFlags = 64896,
-        ContextFlags = 3080192,
-        TypeExcludesFlags = 655360,
+        ReachabilityAndEmitFlags = 1408,
+        ContextFlags = 96256,
+        TypeExcludesFlags = 20480,
     }
     enum ModifierFlags {
         None = 0,
@@ -2145,7 +2139,7 @@ declare namespace ts {
 }
 declare namespace ts {
     /** The version of the TypeScript compiler release */
-    const version = "2.1.3";
+    const version = "2.1.4";
 }
 declare namespace ts {
     type FileWatcherCallback = (fileName: string, removed?: boolean) => void;
diff --git a/lib/typescript.js b/lib/typescript.js
index 29a7baad1a1..cf735e4a3bc 100644
--- a/lib/typescript.js
+++ b/lib/typescript.js
@@ -399,28 +399,22 @@ var ts;
         NodeFlags[NodeFlags["HasImplicitReturn"] = 128] = "HasImplicitReturn";
         NodeFlags[NodeFlags["HasExplicitReturn"] = 256] = "HasExplicitReturn";
         NodeFlags[NodeFlags["GlobalAugmentation"] = 512] = "GlobalAugmentation";
-        NodeFlags[NodeFlags["HasClassExtends"] = 1024] = "HasClassExtends";
-        NodeFlags[NodeFlags["HasDecorators"] = 2048] = "HasDecorators";
-        NodeFlags[NodeFlags["HasParamDecorators"] = 4096] = "HasParamDecorators";
-        NodeFlags[NodeFlags["HasAsyncFunctions"] = 8192] = "HasAsyncFunctions";
-        NodeFlags[NodeFlags["HasSpreadAttribute"] = 16384] = "HasSpreadAttribute";
-        NodeFlags[NodeFlags["HasRestAttribute"] = 32768] = "HasRestAttribute";
-        NodeFlags[NodeFlags["DisallowInContext"] = 65536] = "DisallowInContext";
-        NodeFlags[NodeFlags["YieldContext"] = 131072] = "YieldContext";
-        NodeFlags[NodeFlags["DecoratorContext"] = 262144] = "DecoratorContext";
-        NodeFlags[NodeFlags["AwaitContext"] = 524288] = "AwaitContext";
-        NodeFlags[NodeFlags["ThisNodeHasError"] = 1048576] = "ThisNodeHasError";
-        NodeFlags[NodeFlags["JavaScriptFile"] = 2097152] = "JavaScriptFile";
-        NodeFlags[NodeFlags["ThisNodeOrAnySubNodesHasError"] = 4194304] = "ThisNodeOrAnySubNodesHasError";
-        NodeFlags[NodeFlags["HasAggregatedChildData"] = 8388608] = "HasAggregatedChildData";
+        NodeFlags[NodeFlags["HasAsyncFunctions"] = 1024] = "HasAsyncFunctions";
+        NodeFlags[NodeFlags["DisallowInContext"] = 2048] = "DisallowInContext";
+        NodeFlags[NodeFlags["YieldContext"] = 4096] = "YieldContext";
+        NodeFlags[NodeFlags["DecoratorContext"] = 8192] = "DecoratorContext";
+        NodeFlags[NodeFlags["AwaitContext"] = 16384] = "AwaitContext";
+        NodeFlags[NodeFlags["ThisNodeHasError"] = 32768] = "ThisNodeHasError";
+        NodeFlags[NodeFlags["JavaScriptFile"] = 65536] = "JavaScriptFile";
+        NodeFlags[NodeFlags["ThisNodeOrAnySubNodesHasError"] = 131072] = "ThisNodeOrAnySubNodesHasError";
+        NodeFlags[NodeFlags["HasAggregatedChildData"] = 262144] = "HasAggregatedChildData";
         NodeFlags[NodeFlags["BlockScoped"] = 3] = "BlockScoped";
         NodeFlags[NodeFlags["ReachabilityCheckFlags"] = 384] = "ReachabilityCheckFlags";
-        NodeFlags[NodeFlags["EmitHelperFlags"] = 64512] = "EmitHelperFlags";
-        NodeFlags[NodeFlags["ReachabilityAndEmitFlags"] = 64896] = "ReachabilityAndEmitFlags";
+        NodeFlags[NodeFlags["ReachabilityAndEmitFlags"] = 1408] = "ReachabilityAndEmitFlags";
         // Parsing context flags
-        NodeFlags[NodeFlags["ContextFlags"] = 3080192] = "ContextFlags";
+        NodeFlags[NodeFlags["ContextFlags"] = 96256] = "ContextFlags";
         // Exclude these flags when parsing a Type
-        NodeFlags[NodeFlags["TypeExcludesFlags"] = 655360] = "TypeExcludesFlags";
+        NodeFlags[NodeFlags["TypeExcludesFlags"] = 20480] = "TypeExcludesFlags";
     })(NodeFlags = ts.NodeFlags || (ts.NodeFlags = {}));
     var ModifierFlags;
     (function (ModifierFlags) {
@@ -1066,6 +1060,24 @@ var ts;
         EmitFlags[EmitFlags["NoHoisting"] = 1048576] = "NoHoisting";
         EmitFlags[EmitFlags["HasEndOfDeclarationMarker"] = 2097152] = "HasEndOfDeclarationMarker";
     })(EmitFlags = ts.EmitFlags || (ts.EmitFlags = {}));
+    /**
+     * Used by the checker, this enum keeps track of external emit helpers that should be type
+     * checked.
+     */
+    /* @internal */
+    var ExternalEmitHelpers;
+    (function (ExternalEmitHelpers) {
+        ExternalEmitHelpers[ExternalEmitHelpers["Extends"] = 1] = "Extends";
+        ExternalEmitHelpers[ExternalEmitHelpers["Assign"] = 2] = "Assign";
+        ExternalEmitHelpers[ExternalEmitHelpers["Rest"] = 4] = "Rest";
+        ExternalEmitHelpers[ExternalEmitHelpers["Decorate"] = 8] = "Decorate";
+        ExternalEmitHelpers[ExternalEmitHelpers["Metadata"] = 16] = "Metadata";
+        ExternalEmitHelpers[ExternalEmitHelpers["Param"] = 32] = "Param";
+        ExternalEmitHelpers[ExternalEmitHelpers["Awaiter"] = 64] = "Awaiter";
+        ExternalEmitHelpers[ExternalEmitHelpers["Generator"] = 128] = "Generator";
+        ExternalEmitHelpers[ExternalEmitHelpers["FirstEmitHelper"] = 1] = "FirstEmitHelper";
+        ExternalEmitHelpers[ExternalEmitHelpers["LastEmitHelper"] = 128] = "LastEmitHelper";
+    })(ExternalEmitHelpers = ts.ExternalEmitHelpers || (ts.ExternalEmitHelpers = {}));
     /* @internal */
     var EmitContext;
     (function (EmitContext) {
@@ -1174,7 +1186,7 @@ var ts;
 var ts;
 (function (ts) {
     /** The version of the TypeScript compiler release */
-    ts.version = "2.1.3";
+    ts.version = "2.1.4";
 })(ts || (ts = {}));
 /* @internal */
 (function (ts) {
@@ -4110,6 +4122,7 @@ var ts;
         Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword: { code: 2340, category: ts.DiagnosticCategory.Error, key: "Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword_2340", message: "Only public and protected methods of the base class are accessible via the 'super' keyword." },
         Property_0_is_private_and_only_accessible_within_class_1: { code: 2341, category: ts.DiagnosticCategory.Error, key: "Property_0_is_private_and_only_accessible_within_class_1_2341", message: "Property '{0}' is private and only accessible within class '{1}'." },
         An_index_expression_argument_must_be_of_type_string_number_symbol_or_any: { code: 2342, category: ts.DiagnosticCategory.Error, key: "An_index_expression_argument_must_be_of_type_string_number_symbol_or_any_2342", message: "An index expression argument must be of type 'string', 'number', 'symbol', or 'any'." },
+        This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1: { code: 2343, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1_2343", message: "This syntax requires an imported helper named '{1}', but module '{0}' has no exported member '{1}'." },
         Type_0_does_not_satisfy_the_constraint_1: { code: 2344, category: ts.DiagnosticCategory.Error, key: "Type_0_does_not_satisfy_the_constraint_1_2344", message: "Type '{0}' does not satisfy the constraint '{1}'." },
         Argument_of_type_0_is_not_assignable_to_parameter_of_type_1: { code: 2345, category: ts.DiagnosticCategory.Error, key: "Argument_of_type_0_is_not_assignable_to_parameter_of_type_1_2345", message: "Argument of type '{0}' is not assignable to parameter of type '{1}'." },
         Supplied_parameters_do_not_match_any_signature_of_call_target: { code: 2346, category: ts.DiagnosticCategory.Error, key: "Supplied_parameters_do_not_match_any_signature_of_call_target_2346", message: "Supplied parameters do not match any signature of call target." },
@@ -4120,6 +4133,7 @@ var ts;
         Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature: { code: 2351, category: ts.DiagnosticCategory.Error, key: "Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature_2351", message: "Cannot use 'new' with an expression whose type lacks a call or construct signature." },
         Type_0_cannot_be_converted_to_type_1: { code: 2352, category: ts.DiagnosticCategory.Error, key: "Type_0_cannot_be_converted_to_type_1_2352", message: "Type '{0}' cannot be converted to type '{1}'." },
         Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1: { code: 2353, category: ts.DiagnosticCategory.Error, key: "Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1_2353", message: "Object literal may only specify known properties, and '{0}' does not exist in type '{1}'." },
+        This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found: { code: 2354, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found_2354", message: "This syntax requires an imported helper but module '{0}' cannot be found." },
         A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value: { code: 2355, category: ts.DiagnosticCategory.Error, key: "A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value_2355", message: "A function whose declared type is neither 'void' nor 'any' must return a value." },
         An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type: { code: 2356, category: ts.DiagnosticCategory.Error, key: "An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type_2356", message: "An arithmetic operand must be of type 'any', 'number' or an enum type." },
         The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access: { code: 2357, category: ts.DiagnosticCategory.Error, key: "The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access_2357", message: "The operand of an increment or decrement operator must be a variable or a property access." },
@@ -4426,6 +4440,8 @@ var ts;
         Default_export_of_the_module_has_or_is_using_private_name_0: { code: 4082, category: ts.DiagnosticCategory.Error, key: "Default_export_of_the_module_has_or_is_using_private_name_0_4082", message: "Default export of the module has or is using private name '{0}'." },
         Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1: { code: 4083, category: ts.DiagnosticCategory.Error, key: "Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1_4083", message: "Type parameter '{0}' of exported type alias has or is using private name '{1}'." },
         Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_library_to_resolve_the_conflict: { code: 4090, category: ts.DiagnosticCategory.Message, key: "Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_librar_4090", message: "Conflicting definitions for '{0}' found at '{1}' and '{2}'. Consider installing a specific version of this library to resolve the conflict." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2: { code: 4091, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2_4091", message: "Parameter '{0}' of index signature from exported interface has or is using name '{1}' from private module '{2}'." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1: { code: 4092, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1_4092", message: "Parameter '{0}' of index signature from exported interface has or is using private name '{1}'." },
         The_current_host_does_not_support_the_0_option: { code: 5001, category: ts.DiagnosticCategory.Error, key: "The_current_host_does_not_support_the_0_option_5001", message: "The current host does not support the '{0}' option." },
         Cannot_find_the_common_subdirectory_path_for_the_input_files: { code: 5009, category: ts.DiagnosticCategory.Error, key: "Cannot_find_the_common_subdirectory_path_for_the_input_files_5009", message: "Cannot find the common subdirectory path for the input files." },
         File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0: { code: 5010, category: ts.DiagnosticCategory.Error, key: "File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0_5010", message: "File specification cannot end in a recursive directory wildcard ('**'): '{0}'." },
@@ -6492,24 +6508,24 @@ var ts;
     // Returns true if this node contains a parse error anywhere underneath it.
     function containsParseError(node) {
         aggregateChildData(node);
-        return (node.flags & 4194304 /* ThisNodeOrAnySubNodesHasError */) !== 0;
+        return (node.flags & 131072 /* ThisNodeOrAnySubNodesHasError */) !== 0;
     }
     ts.containsParseError = containsParseError;
     function aggregateChildData(node) {
-        if (!(node.flags & 8388608 /* HasAggregatedChildData */)) {
+        if (!(node.flags & 262144 /* HasAggregatedChildData */)) {
             // A node is considered to contain a parse error if:
             //  a) the parser explicitly marked that it had an error
             //  b) any of it's children reported that it had an error.
-            var thisNodeOrAnySubNodesHasError = ((node.flags & 1048576 /* ThisNodeHasError */) !== 0) ||
+            var thisNodeOrAnySubNodesHasError = ((node.flags & 32768 /* ThisNodeHasError */) !== 0) ||
                 ts.forEachChild(node, containsParseError);
             // If so, mark ourselves accordingly.
             if (thisNodeOrAnySubNodesHasError) {
-                node.flags |= 4194304 /* ThisNodeOrAnySubNodesHasError */;
+                node.flags |= 131072 /* ThisNodeOrAnySubNodesHasError */;
             }
             // Also mark that we've propagated the child information to this node.  This way we can
             // always consult the bit directly on this node without needing to check its children
             // again.
-            node.flags |= 8388608 /* HasAggregatedChildData */;
+            node.flags |= 262144 /* HasAggregatedChildData */;
         }
     }
     function getSourceFileOfNode(node) {
@@ -6774,6 +6790,10 @@ var ts;
         return false;
     }
     ts.isExternalModuleAugmentation = isExternalModuleAugmentation;
+    function isEffectiveExternalModule(node, compilerOptions) {
+        return ts.isExternalModule(node) || compilerOptions.isolatedModules;
+    }
+    ts.isEffectiveExternalModule = isEffectiveExternalModule;
     function isBlockScope(node, parentNode) {
         switch (node.kind) {
             case 261 /* SourceFile */:
@@ -7601,7 +7621,7 @@ var ts;
     }
     ts.isSourceFileJavaScript = isSourceFileJavaScript;
     function isInJavaScriptFile(node) {
-        return node && !!(node.flags & 2097152 /* JavaScriptFile */);
+        return node && !!(node.flags & 65536 /* JavaScriptFile */);
     }
     ts.isInJavaScriptFile = isInJavaScriptFile;
     /**
@@ -7867,7 +7887,7 @@ var ts;
     }
     ts.hasDeclaredRestParameter = hasDeclaredRestParameter;
     function isRestParameter(node) {
-        if (node && (node.flags & 2097152 /* JavaScriptFile */)) {
+        if (node && (node.flags & 65536 /* JavaScriptFile */)) {
             if (node.type && node.type.kind === 275 /* JSDocVariadicType */ ||
                 ts.forEach(getJSDocParameterTags(node), function (t) { return t.typeExpression && t.typeExpression.type.kind === 275 /* JSDocVariadicType */; })) {
                 return true;
@@ -14335,7 +14355,7 @@ var ts;
         // Share a single scanner across all calls to parse a source file.  This helps speed things
         // up by avoiding the cost of creating/compiling scanners over and over again.
         var scanner = ts.createScanner(5 /* Latest */, /*skipTrivia*/ true);
-        var disallowInAndDecoratorContext = 65536 /* DisallowInContext */ | 262144 /* DecoratorContext */;
+        var disallowInAndDecoratorContext = 2048 /* DisallowInContext */ | 8192 /* DecoratorContext */;
         // capture constructors in 'initializeState' to avoid null checks
         var NodeConstructor;
         var TokenConstructor;
@@ -14459,7 +14479,7 @@ var ts;
             identifiers = ts.createMap();
             identifierCount = 0;
             nodeCount = 0;
-            contextFlags = scriptKind === 1 /* JS */ || scriptKind === 2 /* JSX */ ? 2097152 /* JavaScriptFile */ : 0 /* None */;
+            contextFlags = scriptKind === 1 /* JS */ || scriptKind === 2 /* JSX */ ? 65536 /* JavaScriptFile */ : 0 /* None */;
             parseErrorBeforeNextFinishedNode = false;
             // Initialize and prime the scanner before parsing the source elements.
             scanner.setText(sourceText);
@@ -14567,16 +14587,16 @@ var ts;
             }
         }
         function setDisallowInContext(val) {
-            setContextFlag(val, 65536 /* DisallowInContext */);
+            setContextFlag(val, 2048 /* DisallowInContext */);
         }
         function setYieldContext(val) {
-            setContextFlag(val, 131072 /* YieldContext */);
+            setContextFlag(val, 4096 /* YieldContext */);
         }
         function setDecoratorContext(val) {
-            setContextFlag(val, 262144 /* DecoratorContext */);
+            setContextFlag(val, 8192 /* DecoratorContext */);
         }
         function setAwaitContext(val) {
-            setContextFlag(val, 524288 /* AwaitContext */);
+            setContextFlag(val, 16384 /* AwaitContext */);
         }
         function doOutsideOfContext(context, func) {
             // contextFlagsToClear will contain only the context flags that are
@@ -14617,40 +14637,40 @@ var ts;
             return func();
         }
         function allowInAnd(func) {
-            return doOutsideOfContext(65536 /* DisallowInContext */, func);
+            return doOutsideOfContext(2048 /* DisallowInContext */, func);
         }
         function disallowInAnd(func) {
-            return doInsideOfContext(65536 /* DisallowInContext */, func);
+            return doInsideOfContext(2048 /* DisallowInContext */, func);
         }
         function doInYieldContext(func) {
-            return doInsideOfContext(131072 /* YieldContext */, func);
+            return doInsideOfContext(4096 /* YieldContext */, func);
         }
         function doInDecoratorContext(func) {
-            return doInsideOfContext(262144 /* DecoratorContext */, func);
+            return doInsideOfContext(8192 /* DecoratorContext */, func);
         }
         function doInAwaitContext(func) {
-            return doInsideOfContext(524288 /* AwaitContext */, func);
+            return doInsideOfContext(16384 /* AwaitContext */, func);
         }
         function doOutsideOfAwaitContext(func) {
-            return doOutsideOfContext(524288 /* AwaitContext */, func);
+            return doOutsideOfContext(16384 /* AwaitContext */, func);
         }
         function doInYieldAndAwaitContext(func) {
-            return doInsideOfContext(131072 /* YieldContext */ | 524288 /* AwaitContext */, func);
+            return doInsideOfContext(4096 /* YieldContext */ | 16384 /* AwaitContext */, func);
         }
         function inContext(flags) {
             return (contextFlags & flags) !== 0;
         }
         function inYieldContext() {
-            return inContext(131072 /* YieldContext */);
+            return inContext(4096 /* YieldContext */);
         }
         function inDisallowInContext() {
-            return inContext(65536 /* DisallowInContext */);
+            return inContext(2048 /* DisallowInContext */);
         }
         function inDecoratorContext() {
-            return inContext(262144 /* DecoratorContext */);
+            return inContext(8192 /* DecoratorContext */);
         }
         function inAwaitContext() {
-            return inContext(524288 /* AwaitContext */);
+            return inContext(16384 /* AwaitContext */);
         }
         function parseErrorAtCurrentToken(message, arg0) {
             var start = scanner.getTokenPos();
@@ -14854,7 +14874,7 @@ var ts;
             // flag so that we don't mark any subsequent nodes.
             if (parseErrorBeforeNextFinishedNode) {
                 parseErrorBeforeNextFinishedNode = false;
-                node.flags |= 1048576 /* ThisNodeHasError */;
+                node.flags |= 32768 /* ThisNodeHasError */;
             }
             return node;
         }
@@ -15248,7 +15268,7 @@ var ts;
             // differently depending on what mode it is in.
             //
             // This also applies to all our other context flags as well.
-            var nodeContextFlags = node.flags & 3080192 /* ContextFlags */;
+            var nodeContextFlags = node.flags & 96256 /* ContextFlags */;
             if (nodeContextFlags !== contextFlags) {
                 return undefined;
             }
@@ -16253,7 +16273,7 @@ var ts;
         function parseType() {
             // The rules about 'yield' only apply to actual code/expression contexts.  They don't
             // apply to 'type' contexts.  So we disable these parameters here before moving on.
-            return doOutsideOfContext(655360 /* TypeExcludesFlags */, parseTypeWorker);
+            return doOutsideOfContext(20480 /* TypeExcludesFlags */, parseTypeWorker);
         }
         function parseTypeWorker() {
             if (isStartOfFunctionType()) {
@@ -18363,7 +18383,7 @@ var ts;
             // The checker may still error in the static case to explicitly disallow the yield expression.
             property.initializer = ts.hasModifier(property, 32 /* Static */)
                 ? allowInAnd(parseNonParameterInitializer)
-                : doOutsideOfContext(131072 /* YieldContext */ | 65536 /* DisallowInContext */, parseNonParameterInitializer);
+                : doOutsideOfContext(4096 /* YieldContext */ | 2048 /* DisallowInContext */, parseNonParameterInitializer);
             parseSemicolon();
             return addJSDocComment(finishNode(property));
         }
@@ -20844,8 +20864,7 @@ var ts;
                 hasExplicitReturn = false;
                 bindChildren(node);
                 // Reset all reachability check related flags on node (for incremental scenarios)
-                // Reset all emit helper flags on node (for incremental scenarios)
-                node.flags &= ~64896 /* ReachabilityAndEmitFlags */;
+                node.flags &= ~1408 /* ReachabilityAndEmitFlags */;
                 if (!(currentFlow.flags & 1 /* Unreachable */) && containerFlags & 8 /* IsFunctionLike */ && ts.nodeIsPresent(node.body)) {
                     node.flags |= 128 /* HasImplicitReturn */;
                     if (hasExplicitReturn)
@@ -22158,9 +22177,6 @@ var ts;
                     return bindParameter(node);
                 case 223 /* VariableDeclaration */:
                 case 174 /* BindingElement */:
-                    if (node.dotDotDotToken && node.parent.kind === 172 /* ObjectBindingPattern */) {
-                        emitFlags |= 32768 /* HasRestAttribute */;
-                    }
                     return bindVariableDeclarationOrBindingElement(node);
                 case 147 /* PropertyDeclaration */:
                 case 146 /* PropertySignature */:
@@ -22187,7 +22203,6 @@ var ts;
                         }
                         root = root.parent;
                     }
-                    emitFlags |= hasRest ? 32768 /* HasRestAttribute */ : 16384 /* HasSpreadAttribute */;
                     return;
                 case 153 /* CallSignature */:
                 case 154 /* ConstructSignature */:
@@ -22413,14 +22428,6 @@ var ts;
             }
         }
         function bindClassLikeDeclaration(node) {
-            if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
-                if (ts.getClassExtendsHeritageClauseElement(node) !== undefined) {
-                    emitFlags |= 1024 /* HasClassExtends */;
-                }
-                if (ts.nodeIsDecorated(node)) {
-                    emitFlags |= 2048 /* HasDecorators */;
-                }
-            }
             if (node.kind === 226 /* ClassDeclaration */) {
                 bindBlockScopedDeclaration(node, 32 /* Class */, 899519 /* ClassExcludes */);
             }
@@ -22483,11 +22490,6 @@ var ts;
             }
         }
         function bindParameter(node) {
-            if (!ts.isDeclarationFile(file) &&
-                !ts.isInAmbientContext(node) &&
-                ts.nodeIsDecorated(node)) {
-                emitFlags |= (2048 /* HasDecorators */ | 4096 /* HasParamDecorators */);
-            }
             if (inStrictMode) {
                 // It is a SyntaxError if the identifier eval or arguments appears within a FormalParameterList of a
                 // strict mode FunctionLikeDeclaration or FunctionExpression(13.1)
@@ -22509,7 +22511,7 @@ var ts;
         function bindFunctionDeclaration(node) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192 /* HasAsyncFunctions */;
+                    emitFlags |= 1024 /* HasAsyncFunctions */;
                 }
             }
             checkStrictModeFunctionName(node);
@@ -22524,7 +22526,7 @@ var ts;
         function bindFunctionExpression(node) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192 /* HasAsyncFunctions */;
+                    emitFlags |= 1024 /* HasAsyncFunctions */;
                 }
             }
             if (currentFlow) {
@@ -22537,10 +22539,7 @@ var ts;
         function bindPropertyOrMethodOrAccessor(node, symbolFlags, symbolExcludes) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192 /* HasAsyncFunctions */;
-                }
-                if (ts.nodeIsDecorated(node)) {
-                    emitFlags |= 2048 /* HasDecorators */;
+                    emitFlags |= 1024 /* HasAsyncFunctions */;
                 }
             }
             if (currentFlow && ts.isObjectLiteralOrClassExpressionMethod(node)) {
@@ -24132,6 +24131,8 @@ var ts;
         // is because diagnostics can be quite expensive, and we want to allow hosts to bail out if
         // they no longer need the information (for example, if the user started editing again).
         var cancellationToken;
+        var requestedExternalEmitHelpers;
+        var externalHelpersModule;
         var Symbol = ts.objectAllocator.getSymbolConstructor();
         var Type = ts.objectAllocator.getTypeConstructor();
         var Signature = ts.objectAllocator.getSignatureConstructor();
@@ -26872,7 +26873,13 @@ var ts;
             return name.kind === 142 /* ComputedPropertyName */ && !ts.isStringOrNumericLiteral(name.expression);
         }
         function getRestType(source, properties, symbol) {
-            ts.Debug.assert(!!(source.flags & 32768 /* Object */), "Rest types only support object types right now.");
+            source = filterType(source, function (t) { return !(t.flags & 6144 /* Nullable */); });
+            if (source.flags & 8192 /* Never */) {
+                return emptyObjectType;
+            }
+            if (source.flags & 65536 /* Union */) {
+                return mapType(source, function (t) { return getRestType(t, properties, symbol); });
+            }
             var members = ts.createMap();
             var names = ts.createMap();
             for (var _i = 0, properties_2 = properties; _i < properties_2.length; _i++) {
@@ -26913,7 +26920,7 @@ var ts;
             var type;
             if (pattern.kind === 172 /* ObjectBindingPattern */) {
                 if (declaration.dotDotDotToken) {
-                    if (!(parentType.flags & 32768 /* Object */)) {
+                    if (!isValidSpreadType(parentType)) {
                         error(declaration, ts.Diagnostics.Rest_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
@@ -27003,7 +27010,7 @@ var ts;
         }
         // Return the inferred type for a variable, parameter, or property declaration
         function getTypeForVariableLikeDeclaration(declaration, includeOptionality) {
-            if (declaration.flags & 2097152 /* JavaScriptFile */) {
+            if (declaration.flags & 65536 /* JavaScriptFile */) {
                 // If this is a variable in a JavaScript file, then use the JSDoc type (if it has
                 // one as its type), otherwise fallback to the below standard TS codepaths to
                 // try to figure it out.
@@ -27032,7 +27039,7 @@ var ts;
             if (declaration.type) {
                 return addOptionality(getTypeFromTypeNode(declaration.type), /*optional*/ declaration.questionToken && includeOptionality);
             }
-            if ((compilerOptions.noImplicitAny || declaration.flags & 2097152 /* JavaScriptFile */) &&
+            if ((compilerOptions.noImplicitAny || declaration.flags & 65536 /* JavaScriptFile */) &&
                 declaration.kind === 223 /* VariableDeclaration */ && !ts.isBindingPattern(declaration.name) &&
                 !(ts.getCombinedModifierFlags(declaration) & 1 /* Export */) && !ts.isInAmbientContext(declaration)) {
                 // If --noImplicitAny is on or the declaration is in a Javascript file,
@@ -27109,14 +27116,19 @@ var ts;
         // Return the type implied by an object binding pattern
         function getTypeFromObjectBindingPattern(pattern, includePatternInType, reportErrors) {
             var members = ts.createMap();
+            var stringIndexInfo;
             var hasComputedProperties = false;
             ts.forEach(pattern.elements, function (e) {
                 var name = e.propertyName || e.name;
-                if (isComputedNonLiteralName(name) || e.dotDotDotToken) {
-                    // do not include computed properties or rests in the implied type
+                if (isComputedNonLiteralName(name)) {
+                    // do not include computed properties in the implied type
                     hasComputedProperties = true;
                     return;
                 }
+                if (e.dotDotDotToken) {
+                    stringIndexInfo = createIndexInfo(anyType, /*isReadonly*/ false);
+                    return;
+                }
                 var text = ts.getTextOfPropertyName(name);
                 var flags = 4 /* Property */ | 67108864 /* Transient */ | (e.initializer ? 536870912 /* Optional */ : 0);
                 var symbol = createSymbol(flags, text);
@@ -27124,7 +27136,7 @@ var ts;
                 symbol.bindingElement = e;
                 members[symbol.name] = symbol;
             });
-            var result = createAnonymousType(undefined, members, emptyArray, emptyArray, undefined, undefined);
+            var result = createAnonymousType(undefined, members, emptyArray, emptyArray, stringIndexInfo, undefined);
             if (includePatternInType) {
                 result.pattern = pattern;
             }
@@ -27215,7 +27227,7 @@ var ts;
                 if (declaration.kind === 240 /* ExportAssignment */) {
                     return links.type = checkExpression(declaration.expression);
                 }
-                if (declaration.flags & 2097152 /* JavaScriptFile */ && declaration.kind === 286 /* JSDocPropertyTag */ && declaration.typeExpression) {
+                if (declaration.flags & 65536 /* JavaScriptFile */ && declaration.kind === 286 /* JSDocPropertyTag */ && declaration.typeExpression) {
                     return links.type = getTypeFromTypeNode(declaration.typeExpression.type);
                 }
                 // Handle variable, parameter or property
@@ -27231,7 +27243,7 @@ var ts;
                 if (declaration.kind === 192 /* BinaryExpression */ ||
                     declaration.kind === 177 /* PropertyAccessExpression */ && declaration.parent.kind === 192 /* BinaryExpression */) {
                     // Use JS Doc type if present on parent expression statement
-                    if (declaration.flags & 2097152 /* JavaScriptFile */) {
+                    if (declaration.flags & 65536 /* JavaScriptFile */) {
                         var jsdocType = ts.getJSDocType(declaration.parent);
                         if (jsdocType) {
                             return links.type = getTypeFromTypeNode(jsdocType);
@@ -27287,7 +27299,7 @@ var ts;
             if (!links.type) {
                 var getter = ts.getDeclarationOfKind(symbol, 151 /* GetAccessor */);
                 var setter = ts.getDeclarationOfKind(symbol, 152 /* SetAccessor */);
-                if (getter && getter.flags & 2097152 /* JavaScriptFile */) {
+                if (getter && getter.flags & 65536 /* JavaScriptFile */) {
                     var jsDocType = getTypeForVariableLikeDeclarationFromJSDocComment(getter);
                     if (jsDocType) {
                         return links.type = jsDocType;
@@ -28252,7 +28264,7 @@ var ts;
                     var isomorphicProp = isomorphicType && getPropertyOfType(isomorphicType, propName);
                     var isOptional = templateOptional || !!(isomorphicProp && isomorphicProp.flags & 536870912 /* Optional */);
                     var prop = createSymbol(4 /* Property */ | 67108864 /* Transient */ | (isOptional ? 536870912 /* Optional */ : 0), propName);
-                    prop.type = addOptionality(propType, isOptional);
+                    prop.type = propType;
                     prop.isReadonly = templateReadonly || isomorphicProp && isReadonlySymbol(isomorphicProp);
                     members[propName] = prop;
                 }
@@ -28273,7 +28285,7 @@ var ts;
         function getTemplateTypeFromMappedType(type) {
             return type.templateType ||
                 (type.templateType = type.declaration.type ?
-                    instantiateType(getTypeFromTypeNode(type.declaration.type), type.mapper || identityMapper) :
+                    instantiateType(addOptionality(getTypeFromTypeNode(type.declaration.type), !!type.declaration.questionToken), type.mapper || identityMapper) :
                     unknownType);
         }
         function getIsomorphicTypeFromMappedType(type) {
@@ -28563,7 +28575,7 @@ var ts;
             return undefined;
         }
         function getTypeParametersFromJSDocTemplate(declaration) {
-            if (declaration.flags & 2097152 /* JavaScriptFile */) {
+            if (declaration.flags & 65536 /* JavaScriptFile */) {
                 var templateTag = ts.getJSDocTemplateTag(declaration);
                 if (templateTag) {
                     return getTypeParametersFromDeclaration(templateTag.typeParameters);
@@ -28593,7 +28605,7 @@ var ts;
             return result;
         }
         function isJSDocOptionalParameter(node) {
-            if (node.flags & 2097152 /* JavaScriptFile */) {
+            if (node.flags & 65536 /* JavaScriptFile */) {
                 if (node.type && node.type.kind === 273 /* JSDocOptionalType */) {
                     return true;
                 }
@@ -28729,7 +28741,7 @@ var ts;
             else if (declaration.type) {
                 return getTypeFromTypeNode(declaration.type);
             }
-            if (declaration.flags & 2097152 /* JavaScriptFile */) {
+            if (declaration.flags & 65536 /* JavaScriptFile */) {
                 var type = getReturnTypeFromJSDocComment(declaration);
                 if (type && type !== unknownType) {
                     return type;
@@ -29611,7 +29623,7 @@ var ts;
             }
             var mapper = createUnaryTypeMapper(getTypeParameterFromMappedType(type), indexType);
             var templateMapper = type.mapper ? combineTypeMappers(type.mapper, mapper) : mapper;
-            return addOptionality(instantiateType(getTemplateTypeFromMappedType(type), templateMapper), !!type.declaration.questionToken);
+            return instantiateType(getTemplateTypeFromMappedType(type), templateMapper);
         }
         function getIndexedAccessType(objectType, indexType, accessNode) {
             if (indexType.flags & 16384 /* TypeParameter */ ||
@@ -29703,10 +29715,23 @@ var ts;
          * and right = the new element to be spread.
          */
         function getSpreadType(left, right, isFromObjectLiteral) {
-            ts.Debug.assert(!!(left.flags & (32768 /* Object */ | 1 /* Any */)) && !!(right.flags & (32768 /* Object */ | 1 /* Any */)), "Only object types may be spread.");
             if (left.flags & 1 /* Any */ || right.flags & 1 /* Any */) {
                 return anyType;
             }
+            left = filterType(left, function (t) { return !(t.flags & 6144 /* Nullable */); });
+            if (left.flags & 8192 /* Never */) {
+                return right;
+            }
+            right = filterType(right, function (t) { return !(t.flags & 6144 /* Nullable */); });
+            if (right.flags & 8192 /* Never */) {
+                return left;
+            }
+            if (left.flags & 65536 /* Union */) {
+                return mapType(left, function (t) { return getSpreadType(t, right, isFromObjectLiteral); });
+            }
+            if (right.flags & 65536 /* Union */) {
+                return mapType(right, function (t) { return getSpreadType(left, t, isFromObjectLiteral); });
+            }
             var members = ts.createMap();
             var skippedPrivateMembers = ts.createMap();
             var stringIndexInfo;
@@ -31872,6 +31897,8 @@ var ts;
             var typeInferences = createTypeInferencesObject();
             var typeInferencesArray = [typeInferences];
             var templateType = getTemplateTypeFromMappedType(target);
+            var readonlyMask = target.declaration.readonlyToken ? false : true;
+            var optionalMask = target.declaration.questionToken ? 0 : 536870912 /* Optional */;
             var properties = getPropertiesOfType(source);
             var members = createSymbolTable(properties);
             var hasInferredTypes = false;
@@ -31879,10 +31906,10 @@ var ts;
                 var prop = properties_4[_i];
                 var inferredPropType = inferTargetType(getTypeOfSymbol(prop));
                 if (inferredPropType) {
-                    var inferredProp = createSymbol(4 /* Property */ | 67108864 /* Transient */ | prop.flags & 536870912 /* Optional */, prop.name);
+                    var inferredProp = createSymbol(4 /* Property */ | 67108864 /* Transient */ | prop.flags & optionalMask, prop.name);
                     inferredProp.declarations = prop.declarations;
                     inferredProp.type = inferredPropType;
-                    inferredProp.isReadonly = isReadonlySymbol(prop);
+                    inferredProp.isReadonly = readonlyMask && isReadonlySymbol(prop);
                     members[prop.name] = inferredProp;
                     hasInferredTypes = true;
                 }
@@ -31891,7 +31918,7 @@ var ts;
             if (indexInfo) {
                 var inferredIndexType = inferTargetType(indexInfo.type);
                 if (inferredIndexType) {
-                    indexInfo = createIndexInfo(inferredIndexType, indexInfo.isReadonly);
+                    indexInfo = createIndexInfo(inferredIndexType, readonlyMask && indexInfo.isReadonly);
                     hasInferredTypes = true;
                 }
             }
@@ -33414,7 +33441,7 @@ var ts;
                         error(node, ts.Diagnostics.The_arguments_object_cannot_be_referenced_in_an_async_function_or_method_in_ES3_and_ES5_Consider_using_a_standard_function_or_method);
                     }
                 }
-                if (node.flags & 524288 /* AwaitContext */) {
+                if (node.flags & 16384 /* AwaitContext */) {
                     getNodeLinks(container).flags |= 8192 /* CaptureArguments */;
                 }
                 return getTypeOfSymbol(symbol);
@@ -34604,7 +34631,7 @@ var ts;
                         if (impliedProp) {
                             prop.flags |= impliedProp.flags & 536870912 /* Optional */;
                         }
-                        else if (!compilerOptions.suppressExcessPropertyErrors) {
+                        else if (!compilerOptions.suppressExcessPropertyErrors && !getIndexInfoOfType(contextualType, 0 /* String */)) {
                             error(memberDecl.name, ts.Diagnostics.Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1, symbolToString(member), typeToString(contextualType));
                         }
                     }
@@ -34618,6 +34645,9 @@ var ts;
                     member = prop;
                 }
                 else if (memberDecl.kind === 259 /* SpreadAssignment */) {
+                    if (languageVersion < 5 /* ESNext */) {
+                        checkExternalEmitHelpers(memberDecl, 2 /* Assign */);
+                    }
                     if (propertiesArray.length > 0) {
                         spread = getSpreadType(spread, createObjectLiteralType(), /*isFromObjectLiteral*/ true);
                         propertiesArray = [];
@@ -34627,7 +34657,7 @@ var ts;
                         typeFlags = 0;
                     }
                     var type = checkExpression(memberDecl.expression);
-                    if (!(type.flags & (32768 /* Object */ | 1 /* Any */))) {
+                    if (!isValidSpreadType(type)) {
                         error(memberDecl, ts.Diagnostics.Spread_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
@@ -34699,6 +34729,11 @@ var ts;
                 return result;
             }
         }
+        function isValidSpreadType(type) {
+            return !!(type.flags & (1 /* Any */ | 4096 /* Null */ | 2048 /* Undefined */) ||
+                type.flags & 32768 /* Object */ && !isGenericMappedType(type) ||
+                type.flags & 196608 /* UnionOrIntersection */ && !ts.forEach(type.types, function (t) { return !isValidSpreadType(t); }));
+        }
         function checkJsxSelfClosingElement(node) {
             checkJsxOpeningLikeElement(node);
             return jsxElementType || anyType;
@@ -34788,6 +34823,9 @@ var ts;
             return exprType;
         }
         function checkJsxSpreadAttribute(node, elementAttributesType, nameTable) {
+            if (compilerOptions.jsx === 2 /* React */) {
+                checkExternalEmitHelpers(node, 2 /* Assign */);
+            }
             var type = checkExpression(node.expression);
             var props = getPropertiesOfType(type);
             for (var _i = 0, props_2 = props; _i < props_2.length; _i++) {
@@ -37085,7 +37123,7 @@ var ts;
         function checkAwaitExpression(node) {
             // Grammar checking
             if (produceDiagnostics) {
-                if (!(node.flags & 524288 /* AwaitContext */)) {
+                if (!(node.flags & 16384 /* AwaitContext */)) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.await_expression_is_only_allowed_within_an_async_function);
                 }
                 if (isInParameterInitializerBeforeContainingFunction(node)) {
@@ -37262,6 +37300,9 @@ var ts;
                 }
             }
             else if (property.kind === 259 /* SpreadAssignment */) {
+                if (languageVersion < 5 /* ESNext */) {
+                    checkExternalEmitHelpers(property, 4 /* Rest */);
+                }
                 var nonRestNames = [];
                 if (allProperties) {
                     for (var i = 0; i < allProperties.length - 1; i++) {
@@ -37658,7 +37699,7 @@ var ts;
         function checkYieldExpression(node) {
             // Grammar checking
             if (produceDiagnostics) {
-                if (!(node.flags & 131072 /* YieldContext */) || isYieldExpressionInClass(node)) {
+                if (!(node.flags & 4096 /* YieldContext */) || isYieldExpressionInClass(node)) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.A_yield_expression_is_only_allowed_in_a_generator_body);
                 }
                 if (isInParameterInitializerBeforeContainingFunction(node)) {
@@ -38088,6 +38129,12 @@ var ts;
                 node.kind === 154 /* ConstructSignature */) {
                 checkGrammarFunctionLikeDeclaration(node);
             }
+            if (ts.isAsyncFunctionLike(node) && languageVersion < 4 /* ES2017 */) {
+                checkExternalEmitHelpers(node, 64 /* Awaiter */);
+                if (languageVersion < 2 /* ES2015 */) {
+                    checkExternalEmitHelpers(node, 128 /* Generator */);
+                }
+            }
             checkTypeParameters(node.typeParameters);
             ts.forEach(node.parameters, checkParameter);
             if (node.type) {
@@ -39088,7 +39135,13 @@ var ts;
             if (!compilerOptions.experimentalDecorators) {
                 error(node, ts.Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning);
             }
+            var firstDecorator = node.decorators[0];
+            checkExternalEmitHelpers(firstDecorator, 8 /* Decorate */);
+            if (node.kind === 144 /* Parameter */) {
+                checkExternalEmitHelpers(firstDecorator, 32 /* Param */);
+            }
             if (compilerOptions.emitDecoratorMetadata) {
+                checkExternalEmitHelpers(firstDecorator, 16 /* Metadata */);
                 // we only need to perform these checks if we are emitting serialized type metadata for the target of a decorator.
                 switch (node.kind) {
                     case 226 /* ClassDeclaration */:
@@ -39441,7 +39494,7 @@ var ts;
             }
         }
         function checkCollisionWithGlobalPromiseInGeneratedCode(node, name) {
-            if (!needCollisionCheckForIdentifier(node, name, "Promise")) {
+            if (languageVersion >= 4 /* ES2017 */ || !needCollisionCheckForIdentifier(node, name, "Promise")) {
                 return;
             }
             // Uninstantiated modules shouldnt do this check
@@ -39450,7 +39503,7 @@ var ts;
             }
             // In case of variable declaration, node.parent is variable statement so look at the variable statement's parent
             var parent = getDeclarationContainer(node);
-            if (parent.kind === 261 /* SourceFile */ && ts.isExternalOrCommonJsModule(parent) && parent.flags & 8192 /* HasAsyncFunctions */) {
+            if (parent.kind === 261 /* SourceFile */ && ts.isExternalOrCommonJsModule(parent) && parent.flags & 1024 /* HasAsyncFunctions */) {
                 // If the declaration happens to be in external module, report error that Promise is a reserved identifier.
                 error(name, ts.Diagnostics.Duplicate_identifier_0_Compiler_reserves_name_1_in_top_level_scope_of_a_module_containing_async_functions, ts.declarationNameToString(name), ts.declarationNameToString(name));
             }
@@ -39598,6 +39651,9 @@ var ts;
                 }
             }
             if (node.kind === 174 /* BindingElement */) {
+                if (node.parent.kind === 172 /* ObjectBindingPattern */ && languageVersion < 5 /* ESNext */) {
+                    checkExternalEmitHelpers(node, 4 /* Rest */);
+                }
                 // check computed properties inside property names of binding elements
                 if (node.propertyName && node.propertyName.kind === 142 /* ComputedPropertyName */) {
                     checkComputedPropertyName(node.propertyName);
@@ -40136,7 +40192,7 @@ var ts;
         function checkWithStatement(node) {
             // Grammar checking for withStatement
             if (!checkGrammarStatementInAmbientContext(node)) {
-                if (node.flags & 524288 /* AwaitContext */) {
+                if (node.flags & 16384 /* AwaitContext */) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.with_statements_are_not_allowed_in_an_async_function_block);
                 }
             }
@@ -40407,6 +40463,9 @@ var ts;
             checkClassForDuplicateDeclarations(node);
             var baseTypeNode = ts.getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
+                if (languageVersion < 2 /* ES2015 */) {
+                    checkExternalEmitHelpers(baseTypeNode.parent, 1 /* Extends */);
+                }
                 var baseTypes = getBaseTypes(type);
                 if (baseTypes.length && produceDiagnostics) {
                     var baseType_1 = baseTypes[0];
@@ -42606,8 +42665,6 @@ var ts;
             }
             // Initialize global symbol table
             var augmentations;
-            var requestedExternalEmitHelpers = 0;
-            var firstFileRequestingExternalHelpers;
             for (var _b = 0, _c = host.getSourceFiles(); _b < _c.length; _b++) {
                 var file = _c[_b];
                 if (!ts.isExternalOrCommonJsModule(file)) {
@@ -42628,15 +42685,6 @@ var ts;
                         }
                     }
                 }
-                if ((compilerOptions.isolatedModules || ts.isExternalModule(file)) && !file.isDeclarationFile) {
-                    var fileRequestedExternalEmitHelpers = file.flags & 64512 /* EmitHelperFlags */;
-                    if (fileRequestedExternalEmitHelpers) {
-                        requestedExternalEmitHelpers |= fileRequestedExternalEmitHelpers;
-                        if (firstFileRequestingExternalHelpers === undefined) {
-                            firstFileRequestingExternalHelpers = file;
-                        }
-                    }
-                }
             }
             if (augmentations) {
                 // merge module augmentations.
@@ -42695,50 +42743,46 @@ var ts;
             var symbol = getGlobalSymbol("ReadonlyArray", 793064 /* Type */, /*diagnostic*/ undefined);
             globalReadonlyArrayType = symbol && getTypeOfGlobalSymbol(symbol, /*arity*/ 1);
             anyReadonlyArrayType = globalReadonlyArrayType ? createTypeFromGenericGlobalType(globalReadonlyArrayType, [anyType]) : anyArrayType;
-            // If we have specified that we are importing helpers, we should report global
-            // errors if we cannot resolve the helpers external module, or if it does not have
-            // the necessary helpers exported.
-            if (compilerOptions.importHelpers && firstFileRequestingExternalHelpers) {
-                // Find the first reference to the helpers module.
-                var helpersModule = resolveExternalModule(firstFileRequestingExternalHelpers, ts.externalHelpersModuleNameText, ts.Diagnostics.Cannot_find_module_0, 
-                /*errorNode*/ undefined);
-                // If we found the module, report errors if it does not have the necessary exports.
-                if (helpersModule) {
-                    var exports = helpersModule.exports;
-                    if (requestedExternalEmitHelpers & 1024 /* HasClassExtends */ && languageVersion < 2 /* ES2015 */) {
-                        verifyHelperSymbol(exports, "__extends", 107455 /* Value */);
-                    }
-                    if (requestedExternalEmitHelpers & 16384 /* HasSpreadAttribute */ &&
-                        (languageVersion < 5 /* ESNext */ || compilerOptions.jsx === 2 /* React */)) {
-                        verifyHelperSymbol(exports, "__assign", 107455 /* Value */);
-                    }
-                    if (languageVersion < 5 /* ESNext */ && requestedExternalEmitHelpers & 32768 /* HasRestAttribute */) {
-                        verifyHelperSymbol(exports, "__rest", 107455 /* Value */);
-                    }
-                    if (requestedExternalEmitHelpers & 2048 /* HasDecorators */) {
-                        verifyHelperSymbol(exports, "__decorate", 107455 /* Value */);
-                        if (compilerOptions.emitDecoratorMetadata) {
-                            verifyHelperSymbol(exports, "__metadata", 107455 /* Value */);
-                        }
-                    }
-                    if (requestedExternalEmitHelpers & 4096 /* HasParamDecorators */) {
-                        verifyHelperSymbol(exports, "__param", 107455 /* Value */);
-                    }
-                    if (requestedExternalEmitHelpers & 8192 /* HasAsyncFunctions */) {
-                        verifyHelperSymbol(exports, "__awaiter", 107455 /* Value */);
-                        if (languageVersion < 2 /* ES2015 */) {
-                            verifyHelperSymbol(exports, "__generator", 107455 /* Value */);
+        }
+        function checkExternalEmitHelpers(location, helpers) {
+            if ((requestedExternalEmitHelpers & helpers) !== helpers && compilerOptions.importHelpers) {
+                var sourceFile = ts.getSourceFileOfNode(location);
+                if (ts.isEffectiveExternalModule(sourceFile, compilerOptions)) {
+                    var helpersModule = resolveHelpersModule(sourceFile, location);
+                    if (helpersModule !== unknownSymbol) {
+                        var uncheckedHelpers = helpers & ~requestedExternalEmitHelpers;
+                        for (var helper = 1 /* FirstEmitHelper */; helper <= 128 /* LastEmitHelper */; helper <<= 1) {
+                            if (uncheckedHelpers & helper) {
+                                var name_27 = getHelperName(helper);
+                                var symbol = getSymbol(helpersModule.exports, ts.escapeIdentifier(name_27), 107455 /* Value */);
+                                if (!symbol) {
+                                    error(location, ts.Diagnostics.This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1, ts.externalHelpersModuleNameText, name_27);
+                                }
+                            }
                         }
                     }
+                    requestedExternalEmitHelpers |= helpers;
                 }
             }
         }
-        function verifyHelperSymbol(symbols, name, meaning) {
-            var symbol = getSymbol(symbols, ts.escapeIdentifier(name), meaning);
-            if (!symbol) {
-                error(/*location*/ undefined, ts.Diagnostics.Module_0_has_no_exported_member_1, ts.externalHelpersModuleNameText, name);
+        function getHelperName(helper) {
+            switch (helper) {
+                case 1 /* Extends */: return "__extends";
+                case 2 /* Assign */: return "__assign";
+                case 4 /* Rest */: return "__rest";
+                case 8 /* Decorate */: return "__decorate";
+                case 16 /* Metadata */: return "__metadata";
+                case 32 /* Param */: return "__param";
+                case 64 /* Awaiter */: return "__awaiter";
+                case 128 /* Generator */: return "__generator";
             }
         }
+        function resolveHelpersModule(node, errorNode) {
+            if (!externalHelpersModule) {
+                externalHelpersModule = resolveExternalModule(node, ts.externalHelpersModuleNameText, ts.Diagnostics.This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found, errorNode) || unknownSymbol;
+            }
+            return externalHelpersModule;
+        }
         function createInstantiatedPromiseLikeType() {
             var promiseLikeType = getGlobalPromiseLikeType();
             if (promiseLikeType !== emptyGenericType) {
@@ -43273,10 +43317,10 @@ var ts;
                 if (prop.kind === 259 /* SpreadAssignment */) {
                     continue;
                 }
-                var name_27 = prop.name;
-                if (name_27.kind === 142 /* ComputedPropertyName */) {
+                var name_28 = prop.name;
+                if (name_28.kind === 142 /* ComputedPropertyName */) {
                     // If the name is not a ComputedPropertyName, the grammar checking will skip it
-                    checkGrammarComputedPropertyName(name_27);
+                    checkGrammarComputedPropertyName(name_28);
                 }
                 if (prop.kind === 258 /* ShorthandPropertyAssignment */ && !inDestructuring && prop.objectAssignmentInitializer) {
                     // having objectAssignmentInitializer is only valid in ObjectAssignmentPattern
@@ -43304,8 +43348,8 @@ var ts;
                 if (prop.kind === 257 /* PropertyAssignment */ || prop.kind === 258 /* ShorthandPropertyAssignment */) {
                     // Grammar checking for computedPropertyName and shorthandPropertyAssignment
                     checkGrammarForInvalidQuestionMark(prop.questionToken, ts.Diagnostics.An_object_member_cannot_be_declared_optional);
-                    if (name_27.kind === 8 /* NumericLiteral */) {
-                        checkGrammarNumericLiteral(name_27);
+                    if (name_28.kind === 8 /* NumericLiteral */) {
+                        checkGrammarNumericLiteral(name_28);
                     }
                     currentKind = Property;
                 }
@@ -43321,7 +43365,7 @@ var ts;
                 else {
                     ts.Debug.fail("Unexpected syntax kind:" + prop.kind);
                 }
-                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_27);
+                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_28);
                 if (effectiveName === undefined) {
                     continue;
                 }
@@ -43331,18 +43375,18 @@ var ts;
                 else {
                     var existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
-                        grammarErrorOnNode(name_27, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_27));
+                        grammarErrorOnNode(name_28, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_28));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
                             seen[effectiveName] = currentKind | existingKind;
                         }
                         else {
-                            return grammarErrorOnNode(name_27, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
+                            return grammarErrorOnNode(name_28, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
                         }
                     }
                     else {
-                        return grammarErrorOnNode(name_27, ts.Diagnostics.An_object_literal_cannot_have_property_and_accessor_with_the_same_name);
+                        return grammarErrorOnNode(name_28, ts.Diagnostics.An_object_literal_cannot_have_property_and_accessor_with_the_same_name);
                     }
                 }
             }
@@ -43355,12 +43399,12 @@ var ts;
                     continue;
                 }
                 var jsxAttr = attr;
-                var name_28 = jsxAttr.name;
-                if (!seen[name_28.text]) {
-                    seen[name_28.text] = true;
+                var name_29 = jsxAttr.name;
+                if (!seen[name_29.text]) {
+                    seen[name_29.text] = true;
                 }
                 else {
-                    return grammarErrorOnNode(name_28, ts.Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
+                    return grammarErrorOnNode(name_29, ts.Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
                 }
                 var initializer = jsxAttr.initializer;
                 if (initializer && initializer.kind === 252 /* JsxExpression */ && !initializer.expression) {
@@ -44879,11 +44923,11 @@ var ts;
             }
         }
         for (var _i = 0, pendingDeclarations_1 = pendingDeclarations; _i < pendingDeclarations_1.length; _i++) {
-            var _a = pendingDeclarations_1[_i], pendingExpressions_1 = _a.pendingExpressions, name_29 = _a.name, value = _a.value, location_2 = _a.location, original = _a.original;
-            var variable = ts.createVariableDeclaration(name_29, 
+            var _a = pendingDeclarations_1[_i], pendingExpressions_1 = _a.pendingExpressions, name_30 = _a.name, value = _a.value, location_2 = _a.location, original = _a.original;
+            var variable = ts.createVariableDeclaration(name_30, 
             /*type*/ undefined, pendingExpressions_1 ? ts.inlineExpressions(ts.append(pendingExpressions_1, value)) : value, location_2);
             variable.original = original;
-            if (ts.isIdentifier(name_29)) {
+            if (ts.isIdentifier(name_30)) {
                 ts.setEmitFlags(variable, 64 /* NoNestedSourceMaps */);
             }
             ts.aggregateTransformFlags(variable);
@@ -45087,8 +45131,8 @@ var ts;
             return ts.createElementAccess(value, argumentExpression);
         }
         else {
-            var name_30 = ts.createIdentifier(ts.unescapeIdentifier(propertyName.text));
-            return ts.createPropertyAccess(value, name_30);
+            var name_31 = ts.createIdentifier(ts.unescapeIdentifier(propertyName.text));
+            return ts.createPropertyAccess(value, name_31);
         }
     }
     /**
@@ -45141,7 +45185,7 @@ var ts;
     var restHelper = {
         name: "typescript:rest",
         scoped: false,
-        text: "\n            var __rest = (this && this.__rest) || function (s, e) {\n                var t = {};\n                for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)\n                    t[p] = s[p];\n                if (typeof Object.getOwnPropertySymbols === \"function\")\n                    for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)\n                        t[p[i]] = s[p[i]];\n                return t;\n            };"
+        text: "\n            var __rest = (this && this.__rest) || function (s, e) {\n                var t = {};\n                for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)\n                    t[p] = s[p];\n                if (s != null && typeof Object.getOwnPropertySymbols === \"function\")\n                    for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)\n                        t[p[i]] = s[p[i]];\n                return t;\n            };"
     };
     /** Given value: o, propName: p, pattern: { a, b, ...p } from the original statement
      * `{ a, b, ...p } = o`, create `p = __rest(o, ["a", "b"]);`*/
@@ -46712,14 +46756,14 @@ var ts;
                 case 70 /* Identifier */:
                     // Create a clone of the name with a new parent, and treat it as if it were
                     // a source tree node for the purposes of the checker.
-                    var name_31 = ts.getMutableClone(node);
-                    name_31.flags &= ~8 /* Synthesized */;
-                    name_31.original = undefined;
-                    name_31.parent = currentScope;
+                    var name_32 = ts.getMutableClone(node);
+                    name_32.flags &= ~8 /* Synthesized */;
+                    name_32.original = undefined;
+                    name_32.parent = currentScope;
                     if (useFallback) {
-                        return ts.createLogicalAnd(ts.createStrictInequality(ts.createTypeOf(name_31), ts.createLiteral("undefined")), name_31);
+                        return ts.createLogicalAnd(ts.createStrictInequality(ts.createTypeOf(name_32), ts.createLiteral("undefined")), name_32);
                     }
-                    return name_31;
+                    return name_32;
                 case 141 /* QualifiedName */:
                     return serializeQualifiedNameAsExpression(node, useFallback);
             }
@@ -46766,7 +46810,7 @@ var ts;
                     : name.expression;
             }
             else if (ts.isIdentifier(name)) {
-                return ts.createLiteral(name.text);
+                return ts.createLiteral(ts.unescapeIdentifier(name.text));
             }
             else {
                 return ts.getSynthesizedClone(name);
@@ -47245,9 +47289,9 @@ var ts;
          */
         function isFirstEmittedDeclarationInScope(node) {
             if (currentScopeFirstDeclarationsOfName) {
-                var name_32 = node.symbol && node.symbol.name;
-                if (name_32) {
-                    return currentScopeFirstDeclarationsOfName[name_32] === node;
+                var name_33 = node.symbol && node.symbol.name;
+                if (name_33) {
+                    return currentScopeFirstDeclarationsOfName[name_33] === node;
                 }
             }
             return false;
@@ -47755,16 +47799,16 @@ var ts;
         }
         function substituteShorthandPropertyAssignment(node) {
             if (enabledSubstitutions & 2 /* NamespaceExports */) {
-                var name_33 = node.name;
-                var exportedName = trySubstituteNamespaceExportedName(name_33);
+                var name_34 = node.name;
+                var exportedName = trySubstituteNamespaceExportedName(name_34);
                 if (exportedName) {
                     // A shorthand property with an assignment initializer is probably part of a
                     // destructuring assignment
                     if (node.objectAssignmentInitializer) {
                         var initializer = ts.createAssignment(exportedName, node.objectAssignmentInitializer);
-                        return ts.createPropertyAssignment(name_33, initializer, /*location*/ node);
+                        return ts.createPropertyAssignment(name_34, initializer, /*location*/ node);
                     }
-                    return ts.createPropertyAssignment(name_33, exportedName, /*location*/ node);
+                    return ts.createPropertyAssignment(name_34, exportedName, /*location*/ node);
                 }
             }
             return node;
@@ -48379,12 +48423,12 @@ var ts;
                 return getTagName(node.openingElement);
             }
             else {
-                var name_34 = node.tagName;
-                if (ts.isIdentifier(name_34) && ts.isIntrinsicJsxName(name_34.text)) {
-                    return ts.createLiteral(name_34.text);
+                var name_35 = node.tagName;
+                if (ts.isIdentifier(name_35) && ts.isIntrinsicJsxName(name_35.text)) {
+                    return ts.createLiteral(name_35.text);
                 }
                 else {
-                    return ts.createExpressionFromEntityName(name_34);
+                    return ts.createExpressionFromEntityName(name_35);
                 }
             }
         }
@@ -49920,17 +49964,17 @@ var ts;
             }
             for (var _i = 0, _a = node.parameters; _i < _a.length; _i++) {
                 var parameter = _a[_i];
-                var name_35 = parameter.name, initializer = parameter.initializer, dotDotDotToken = parameter.dotDotDotToken;
+                var name_36 = parameter.name, initializer = parameter.initializer, dotDotDotToken = parameter.dotDotDotToken;
                 // A rest parameter cannot have a binding pattern or an initializer,
                 // so let's just ignore it.
                 if (dotDotDotToken) {
                     continue;
                 }
-                if (ts.isBindingPattern(name_35)) {
-                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name_35, initializer);
+                if (ts.isBindingPattern(name_36)) {
+                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name_36, initializer);
                 }
                 else if (initializer) {
-                    addDefaultValueAssignmentForInitializer(statements, parameter, name_35, initializer);
+                    addDefaultValueAssignmentForInitializer(statements, parameter, name_36, initializer);
                 }
             }
         }
@@ -53204,9 +53248,9 @@ var ts;
                 if (ts.isIdentifier(original) && original.parent) {
                     var declaration = resolver.getReferencedValueDeclaration(original);
                     if (declaration) {
-                        var name_36 = ts.getProperty(renamedCatchVariableDeclarations, String(ts.getOriginalNodeId(declaration)));
-                        if (name_36) {
-                            var clone_6 = ts.getMutableClone(name_36);
+                        var name_37 = ts.getProperty(renamedCatchVariableDeclarations, String(ts.getOriginalNodeId(declaration)));
+                        if (name_37) {
+                            var clone_6 = ts.getMutableClone(name_37);
                             ts.setSourceMapRange(clone_6, node);
                             ts.setCommentRange(clone_6, node);
                             return clone_6;
@@ -56755,8 +56799,8 @@ var ts;
                         /*location*/ node);
                     }
                     else if (ts.isImportSpecifier(importDeclaration)) {
-                        var name_37 = importDeclaration.propertyName || importDeclaration.name;
-                        return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent.parent.parent), ts.getSynthesizedClone(name_37), 
+                        var name_38 = importDeclaration.propertyName || importDeclaration.name;
+                        return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent.parent.parent), ts.getSynthesizedClone(name_38), 
                         /*location*/ node);
                     }
                 }
@@ -58297,9 +58341,9 @@ var ts;
             var count = 0;
             while (true) {
                 count++;
-                var name_38 = baseName + "_" + count;
-                if (!(name_38 in currentIdentifiers)) {
-                    return name_38;
+                var name_39 = baseName + "_" + count;
+                if (!(name_39 in currentIdentifiers)) {
+                    return name_39;
                 }
             }
         }
@@ -59247,6 +59291,11 @@ var ts;
                         return symbolAccessibilityResult.errorModuleName ?
                             ts.Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
                             ts.Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_private_name_1;
+                    case 155 /* IndexSignature */:
+                        // Interfaces cannot have parameter types that cannot be named
+                        return symbolAccessibilityResult.errorModuleName ?
+                            ts.Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
+                            ts.Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1;
                     case 149 /* MethodDeclaration */:
                     case 148 /* MethodSignature */:
                         if (ts.hasModifier(node.parent, 32 /* Static */)) {
@@ -61607,10 +61656,10 @@ var ts;
         */
         function makeTempVariableName(flags) {
             if (flags && !(tempFlags & flags)) {
-                var name_39 = flags === 268435456 /* _i */ ? "_i" : "_n";
-                if (isUniqueName(name_39)) {
+                var name_40 = flags === 268435456 /* _i */ ? "_i" : "_n";
+                if (isUniqueName(name_40)) {
                     tempFlags |= flags;
-                    return name_39;
+                    return name_40;
                 }
             }
             while (true) {
@@ -61618,11 +61667,11 @@ var ts;
                 tempFlags++;
                 // Skip over 'i' and 'n'
                 if (count !== 8 && count !== 13) {
-                    var name_40 = count < 26
+                    var name_41 = count < 26
                         ? "_" + String.fromCharCode(97 /* a */ + count)
                         : "_" + (count - 26);
-                    if (isUniqueName(name_40)) {
-                        return name_40;
+                    if (isUniqueName(name_41)) {
+                        return name_41;
                     }
                 }
             }
@@ -62073,10 +62122,10 @@ var ts;
         var resolutions = [];
         var cache = ts.createMap();
         for (var _i = 0, names_1 = names; _i < names_1.length; _i++) {
-            var name_41 = names_1[_i];
-            var result = name_41 in cache
-                ? cache[name_41]
-                : cache[name_41] = loader(name_41, containingFile);
+            var name_42 = names_1[_i];
+            var result = name_42 in cache
+                ? cache[name_42]
+                : cache[name_42] = loader(name_42, containingFile);
             resolutions.push(result);
         }
         return resolutions;
@@ -64125,11 +64174,11 @@ var ts;
         function serializeCompilerOptions(options) {
             var result = ts.createMap();
             var optionsNameMap = getOptionNameMap().optionNameMap;
-            for (var name_42 in options) {
-                if (ts.hasProperty(options, name_42)) {
+            for (var name_43 in options) {
+                if (ts.hasProperty(options, name_43)) {
                     // tsconfig only options cannot be specified via command line,
                     // so we can assume that only types that can appear here string | number | boolean
-                    switch (name_42) {
+                    switch (name_43) {
                         case "init":
                         case "watch":
                         case "version":
@@ -64137,14 +64186,14 @@ var ts;
                         case "project":
                             break;
                         default:
-                            var value = options[name_42];
-                            var optionDefinition = optionsNameMap[name_42.toLowerCase()];
+                            var value = options[name_43];
+                            var optionDefinition = optionsNameMap[name_43.toLowerCase()];
                             if (optionDefinition) {
                                 var customTypeMap = getCustomTypeMapOfCommandLineOption(optionDefinition);
                                 if (!customTypeMap) {
                                     // There is no map associated with this compiler option then use the value as-is
                                     // This is the case if the value is expect to be string, number, boolean or list of string
-                                    result[name_42] = value;
+                                    result[name_43] = value;
                                 }
                                 else {
                                     if (optionDefinition.type === "list") {
@@ -64153,11 +64202,11 @@ var ts;
                                             var element = _a[_i];
                                             convertedValue.push(getNameOfCompilerOptionValue(element, customTypeMap));
                                         }
-                                        result[name_42] = convertedValue;
+                                        result[name_43] = convertedValue;
                                     }
                                     else {
                                         // There is a typeMap associated with this command-line option so use it to map value back to its name
-                                        result[name_42] = getNameOfCompilerOptionValue(value, customTypeMap);
+                                        result[name_43] = getNameOfCompilerOptionValue(value, customTypeMap);
                                     }
                                 }
                             }
@@ -67190,14 +67239,14 @@ var ts;
             function getJavaScriptCompletionEntries(sourceFile, position, uniqueNames) {
                 var entries = [];
                 var nameTable = ts.getNameTable(sourceFile);
-                for (var name_43 in nameTable) {
+                for (var name_44 in nameTable) {
                     // Skip identifiers produced only from the current location
-                    if (nameTable[name_43] === position) {
+                    if (nameTable[name_44] === position) {
                         continue;
                     }
-                    if (!uniqueNames[name_43]) {
-                        uniqueNames[name_43] = name_43;
-                        var displayName = getCompletionEntryDisplayName(ts.unescapeIdentifier(name_43), compilerOptions.target, /*performCharacterChecks*/ true);
+                    if (!uniqueNames[name_44]) {
+                        uniqueNames[name_44] = name_44;
+                        var displayName = getCompletionEntryDisplayName(ts.unescapeIdentifier(name_44), compilerOptions.target, /*performCharacterChecks*/ true);
                         if (displayName) {
                             var entry = {
                                 name: displayName,
@@ -68502,8 +68551,8 @@ var ts;
                     if (element.getStart() <= position && position <= element.getEnd()) {
                         continue;
                     }
-                    var name_44 = element.propertyName || element.name;
-                    existingImportsOrExports[name_44.text] = true;
+                    var name_45 = element.propertyName || element.name;
+                    existingImportsOrExports[name_45.text] = true;
                 }
                 if (!ts.someProperties(existingImportsOrExports)) {
                     return ts.filter(exportsOfModule, function (e) { return e.name !== "default"; });
@@ -71120,9 +71169,9 @@ var ts;
                 }
             }
             // Add the cached typing locations for inferred typings that are already installed
-            for (var name_45 in packageNameToTypingLocation) {
-                if (name_45 in inferredTypings && !inferredTypings[name_45]) {
-                    inferredTypings[name_45] = packageNameToTypingLocation[name_45];
+            for (var name_46 in packageNameToTypingLocation) {
+                if (name_46 in inferredTypings && !inferredTypings[name_46]) {
+                    inferredTypings[name_46] = packageNameToTypingLocation[name_46];
                 }
             }
             // Remove typings that the user has added to the exclude list
@@ -71260,12 +71309,12 @@ var ts;
                     return;
                 }
                 var nameToDeclarations = sourceFile.getNamedDeclarations();
-                for (var name_46 in nameToDeclarations) {
-                    var declarations = nameToDeclarations[name_46];
+                for (var name_47 in nameToDeclarations) {
+                    var declarations = nameToDeclarations[name_47];
                     if (declarations) {
                         // First do a quick check to see if the name of the declaration matches the
                         // last portion of the (possibly) dotted name they're searching for.
-                        var matches = patternMatcher.getMatchesForLastSegmentOfPattern(name_46);
+                        var matches = patternMatcher.getMatchesForLastSegmentOfPattern(name_47);
                         if (!matches) {
                             continue;
                         }
@@ -71278,14 +71327,14 @@ var ts;
                                 if (!containers) {
                                     return undefined;
                                 }
-                                matches = patternMatcher.getMatches(containers, name_46);
+                                matches = patternMatcher.getMatches(containers, name_47);
                                 if (!matches) {
                                     continue;
                                 }
                             }
                             var fileName = sourceFile.fileName;
                             var matchKind = bestMatchKind(matches);
-                            rawItems.push({ name: name_46, fileName: fileName, matchKind: matchKind, isCaseSensitive: allMatchesAreCaseSensitive(matches), declaration: declaration });
+                            rawItems.push({ name: name_47, fileName: fileName, matchKind: matchKind, isCaseSensitive: allMatchesAreCaseSensitive(matches), declaration: declaration });
                         }
                     }
                 }
@@ -71574,9 +71623,9 @@ var ts;
                 case 174 /* BindingElement */:
                 case 223 /* VariableDeclaration */:
                     var decl = node;
-                    var name_47 = decl.name;
-                    if (ts.isBindingPattern(name_47)) {
-                        addChildrenRecursively(name_47);
+                    var name_48 = decl.name;
+                    if (ts.isBindingPattern(name_48)) {
+                        addChildrenRecursively(name_48);
                     }
                     else if (decl.initializer && isFunctionOrClassExpression(decl.initializer)) {
                         // For `const x = function() {}`, just use the function node, not the const.
@@ -75075,9 +75124,9 @@ var ts;
             }
             Rules.prototype.getRuleName = function (rule) {
                 var o = this;
-                for (var name_48 in o) {
-                    if (o[name_48] === rule) {
-                        return name_48;
+                for (var name_49 in o) {
+                    if (o[name_49] === rule) {
+                        return name_49;
                     }
                 }
                 throw new Error("Unknown rule");
diff --git a/lib/typescriptServices.d.ts b/lib/typescriptServices.d.ts
index e15772fb840..dd305a97a9d 100644
--- a/lib/typescriptServices.d.ts
+++ b/lib/typescriptServices.d.ts
@@ -378,26 +378,20 @@ declare namespace ts {
         HasImplicitReturn = 128,
         HasExplicitReturn = 256,
         GlobalAugmentation = 512,
-        HasClassExtends = 1024,
-        HasDecorators = 2048,
-        HasParamDecorators = 4096,
-        HasAsyncFunctions = 8192,
-        HasSpreadAttribute = 16384,
-        HasRestAttribute = 32768,
-        DisallowInContext = 65536,
-        YieldContext = 131072,
-        DecoratorContext = 262144,
-        AwaitContext = 524288,
-        ThisNodeHasError = 1048576,
-        JavaScriptFile = 2097152,
-        ThisNodeOrAnySubNodesHasError = 4194304,
-        HasAggregatedChildData = 8388608,
+        HasAsyncFunctions = 1024,
+        DisallowInContext = 2048,
+        YieldContext = 4096,
+        DecoratorContext = 8192,
+        AwaitContext = 16384,
+        ThisNodeHasError = 32768,
+        JavaScriptFile = 65536,
+        ThisNodeOrAnySubNodesHasError = 131072,
+        HasAggregatedChildData = 262144,
         BlockScoped = 3,
         ReachabilityCheckFlags = 384,
-        EmitHelperFlags = 64512,
-        ReachabilityAndEmitFlags = 64896,
-        ContextFlags = 3080192,
-        TypeExcludesFlags = 655360,
+        ReachabilityAndEmitFlags = 1408,
+        ContextFlags = 96256,
+        TypeExcludesFlags = 20480,
     }
     enum ModifierFlags {
         None = 0,
@@ -2145,7 +2139,7 @@ declare namespace ts {
 }
 declare namespace ts {
     /** The version of the TypeScript compiler release */
-    const version = "2.1.3";
+    const version = "2.1.4";
 }
 declare namespace ts {
     type FileWatcherCallback = (fileName: string, removed?: boolean) => void;
diff --git a/lib/typescriptServices.js b/lib/typescriptServices.js
index 29a7baad1a1..cf735e4a3bc 100644
--- a/lib/typescriptServices.js
+++ b/lib/typescriptServices.js
@@ -399,28 +399,22 @@ var ts;
         NodeFlags[NodeFlags["HasImplicitReturn"] = 128] = "HasImplicitReturn";
         NodeFlags[NodeFlags["HasExplicitReturn"] = 256] = "HasExplicitReturn";
         NodeFlags[NodeFlags["GlobalAugmentation"] = 512] = "GlobalAugmentation";
-        NodeFlags[NodeFlags["HasClassExtends"] = 1024] = "HasClassExtends";
-        NodeFlags[NodeFlags["HasDecorators"] = 2048] = "HasDecorators";
-        NodeFlags[NodeFlags["HasParamDecorators"] = 4096] = "HasParamDecorators";
-        NodeFlags[NodeFlags["HasAsyncFunctions"] = 8192] = "HasAsyncFunctions";
-        NodeFlags[NodeFlags["HasSpreadAttribute"] = 16384] = "HasSpreadAttribute";
-        NodeFlags[NodeFlags["HasRestAttribute"] = 32768] = "HasRestAttribute";
-        NodeFlags[NodeFlags["DisallowInContext"] = 65536] = "DisallowInContext";
-        NodeFlags[NodeFlags["YieldContext"] = 131072] = "YieldContext";
-        NodeFlags[NodeFlags["DecoratorContext"] = 262144] = "DecoratorContext";
-        NodeFlags[NodeFlags["AwaitContext"] = 524288] = "AwaitContext";
-        NodeFlags[NodeFlags["ThisNodeHasError"] = 1048576] = "ThisNodeHasError";
-        NodeFlags[NodeFlags["JavaScriptFile"] = 2097152] = "JavaScriptFile";
-        NodeFlags[NodeFlags["ThisNodeOrAnySubNodesHasError"] = 4194304] = "ThisNodeOrAnySubNodesHasError";
-        NodeFlags[NodeFlags["HasAggregatedChildData"] = 8388608] = "HasAggregatedChildData";
+        NodeFlags[NodeFlags["HasAsyncFunctions"] = 1024] = "HasAsyncFunctions";
+        NodeFlags[NodeFlags["DisallowInContext"] = 2048] = "DisallowInContext";
+        NodeFlags[NodeFlags["YieldContext"] = 4096] = "YieldContext";
+        NodeFlags[NodeFlags["DecoratorContext"] = 8192] = "DecoratorContext";
+        NodeFlags[NodeFlags["AwaitContext"] = 16384] = "AwaitContext";
+        NodeFlags[NodeFlags["ThisNodeHasError"] = 32768] = "ThisNodeHasError";
+        NodeFlags[NodeFlags["JavaScriptFile"] = 65536] = "JavaScriptFile";
+        NodeFlags[NodeFlags["ThisNodeOrAnySubNodesHasError"] = 131072] = "ThisNodeOrAnySubNodesHasError";
+        NodeFlags[NodeFlags["HasAggregatedChildData"] = 262144] = "HasAggregatedChildData";
         NodeFlags[NodeFlags["BlockScoped"] = 3] = "BlockScoped";
         NodeFlags[NodeFlags["ReachabilityCheckFlags"] = 384] = "ReachabilityCheckFlags";
-        NodeFlags[NodeFlags["EmitHelperFlags"] = 64512] = "EmitHelperFlags";
-        NodeFlags[NodeFlags["ReachabilityAndEmitFlags"] = 64896] = "ReachabilityAndEmitFlags";
+        NodeFlags[NodeFlags["ReachabilityAndEmitFlags"] = 1408] = "ReachabilityAndEmitFlags";
         // Parsing context flags
-        NodeFlags[NodeFlags["ContextFlags"] = 3080192] = "ContextFlags";
+        NodeFlags[NodeFlags["ContextFlags"] = 96256] = "ContextFlags";
         // Exclude these flags when parsing a Type
-        NodeFlags[NodeFlags["TypeExcludesFlags"] = 655360] = "TypeExcludesFlags";
+        NodeFlags[NodeFlags["TypeExcludesFlags"] = 20480] = "TypeExcludesFlags";
     })(NodeFlags = ts.NodeFlags || (ts.NodeFlags = {}));
     var ModifierFlags;
     (function (ModifierFlags) {
@@ -1066,6 +1060,24 @@ var ts;
         EmitFlags[EmitFlags["NoHoisting"] = 1048576] = "NoHoisting";
         EmitFlags[EmitFlags["HasEndOfDeclarationMarker"] = 2097152] = "HasEndOfDeclarationMarker";
     })(EmitFlags = ts.EmitFlags || (ts.EmitFlags = {}));
+    /**
+     * Used by the checker, this enum keeps track of external emit helpers that should be type
+     * checked.
+     */
+    /* @internal */
+    var ExternalEmitHelpers;
+    (function (ExternalEmitHelpers) {
+        ExternalEmitHelpers[ExternalEmitHelpers["Extends"] = 1] = "Extends";
+        ExternalEmitHelpers[ExternalEmitHelpers["Assign"] = 2] = "Assign";
+        ExternalEmitHelpers[ExternalEmitHelpers["Rest"] = 4] = "Rest";
+        ExternalEmitHelpers[ExternalEmitHelpers["Decorate"] = 8] = "Decorate";
+        ExternalEmitHelpers[ExternalEmitHelpers["Metadata"] = 16] = "Metadata";
+        ExternalEmitHelpers[ExternalEmitHelpers["Param"] = 32] = "Param";
+        ExternalEmitHelpers[ExternalEmitHelpers["Awaiter"] = 64] = "Awaiter";
+        ExternalEmitHelpers[ExternalEmitHelpers["Generator"] = 128] = "Generator";
+        ExternalEmitHelpers[ExternalEmitHelpers["FirstEmitHelper"] = 1] = "FirstEmitHelper";
+        ExternalEmitHelpers[ExternalEmitHelpers["LastEmitHelper"] = 128] = "LastEmitHelper";
+    })(ExternalEmitHelpers = ts.ExternalEmitHelpers || (ts.ExternalEmitHelpers = {}));
     /* @internal */
     var EmitContext;
     (function (EmitContext) {
@@ -1174,7 +1186,7 @@ var ts;
 var ts;
 (function (ts) {
     /** The version of the TypeScript compiler release */
-    ts.version = "2.1.3";
+    ts.version = "2.1.4";
 })(ts || (ts = {}));
 /* @internal */
 (function (ts) {
@@ -4110,6 +4122,7 @@ var ts;
         Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword: { code: 2340, category: ts.DiagnosticCategory.Error, key: "Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword_2340", message: "Only public and protected methods of the base class are accessible via the 'super' keyword." },
         Property_0_is_private_and_only_accessible_within_class_1: { code: 2341, category: ts.DiagnosticCategory.Error, key: "Property_0_is_private_and_only_accessible_within_class_1_2341", message: "Property '{0}' is private and only accessible within class '{1}'." },
         An_index_expression_argument_must_be_of_type_string_number_symbol_or_any: { code: 2342, category: ts.DiagnosticCategory.Error, key: "An_index_expression_argument_must_be_of_type_string_number_symbol_or_any_2342", message: "An index expression argument must be of type 'string', 'number', 'symbol', or 'any'." },
+        This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1: { code: 2343, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1_2343", message: "This syntax requires an imported helper named '{1}', but module '{0}' has no exported member '{1}'." },
         Type_0_does_not_satisfy_the_constraint_1: { code: 2344, category: ts.DiagnosticCategory.Error, key: "Type_0_does_not_satisfy_the_constraint_1_2344", message: "Type '{0}' does not satisfy the constraint '{1}'." },
         Argument_of_type_0_is_not_assignable_to_parameter_of_type_1: { code: 2345, category: ts.DiagnosticCategory.Error, key: "Argument_of_type_0_is_not_assignable_to_parameter_of_type_1_2345", message: "Argument of type '{0}' is not assignable to parameter of type '{1}'." },
         Supplied_parameters_do_not_match_any_signature_of_call_target: { code: 2346, category: ts.DiagnosticCategory.Error, key: "Supplied_parameters_do_not_match_any_signature_of_call_target_2346", message: "Supplied parameters do not match any signature of call target." },
@@ -4120,6 +4133,7 @@ var ts;
         Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature: { code: 2351, category: ts.DiagnosticCategory.Error, key: "Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature_2351", message: "Cannot use 'new' with an expression whose type lacks a call or construct signature." },
         Type_0_cannot_be_converted_to_type_1: { code: 2352, category: ts.DiagnosticCategory.Error, key: "Type_0_cannot_be_converted_to_type_1_2352", message: "Type '{0}' cannot be converted to type '{1}'." },
         Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1: { code: 2353, category: ts.DiagnosticCategory.Error, key: "Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1_2353", message: "Object literal may only specify known properties, and '{0}' does not exist in type '{1}'." },
+        This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found: { code: 2354, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found_2354", message: "This syntax requires an imported helper but module '{0}' cannot be found." },
         A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value: { code: 2355, category: ts.DiagnosticCategory.Error, key: "A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value_2355", message: "A function whose declared type is neither 'void' nor 'any' must return a value." },
         An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type: { code: 2356, category: ts.DiagnosticCategory.Error, key: "An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type_2356", message: "An arithmetic operand must be of type 'any', 'number' or an enum type." },
         The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access: { code: 2357, category: ts.DiagnosticCategory.Error, key: "The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access_2357", message: "The operand of an increment or decrement operator must be a variable or a property access." },
@@ -4426,6 +4440,8 @@ var ts;
         Default_export_of_the_module_has_or_is_using_private_name_0: { code: 4082, category: ts.DiagnosticCategory.Error, key: "Default_export_of_the_module_has_or_is_using_private_name_0_4082", message: "Default export of the module has or is using private name '{0}'." },
         Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1: { code: 4083, category: ts.DiagnosticCategory.Error, key: "Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1_4083", message: "Type parameter '{0}' of exported type alias has or is using private name '{1}'." },
         Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_library_to_resolve_the_conflict: { code: 4090, category: ts.DiagnosticCategory.Message, key: "Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_librar_4090", message: "Conflicting definitions for '{0}' found at '{1}' and '{2}'. Consider installing a specific version of this library to resolve the conflict." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2: { code: 4091, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2_4091", message: "Parameter '{0}' of index signature from exported interface has or is using name '{1}' from private module '{2}'." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1: { code: 4092, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1_4092", message: "Parameter '{0}' of index signature from exported interface has or is using private name '{1}'." },
         The_current_host_does_not_support_the_0_option: { code: 5001, category: ts.DiagnosticCategory.Error, key: "The_current_host_does_not_support_the_0_option_5001", message: "The current host does not support the '{0}' option." },
         Cannot_find_the_common_subdirectory_path_for_the_input_files: { code: 5009, category: ts.DiagnosticCategory.Error, key: "Cannot_find_the_common_subdirectory_path_for_the_input_files_5009", message: "Cannot find the common subdirectory path for the input files." },
         File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0: { code: 5010, category: ts.DiagnosticCategory.Error, key: "File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0_5010", message: "File specification cannot end in a recursive directory wildcard ('**'): '{0}'." },
@@ -6492,24 +6508,24 @@ var ts;
     // Returns true if this node contains a parse error anywhere underneath it.
     function containsParseError(node) {
         aggregateChildData(node);
-        return (node.flags & 4194304 /* ThisNodeOrAnySubNodesHasError */) !== 0;
+        return (node.flags & 131072 /* ThisNodeOrAnySubNodesHasError */) !== 0;
     }
     ts.containsParseError = containsParseError;
     function aggregateChildData(node) {
-        if (!(node.flags & 8388608 /* HasAggregatedChildData */)) {
+        if (!(node.flags & 262144 /* HasAggregatedChildData */)) {
             // A node is considered to contain a parse error if:
             //  a) the parser explicitly marked that it had an error
             //  b) any of it's children reported that it had an error.
-            var thisNodeOrAnySubNodesHasError = ((node.flags & 1048576 /* ThisNodeHasError */) !== 0) ||
+            var thisNodeOrAnySubNodesHasError = ((node.flags & 32768 /* ThisNodeHasError */) !== 0) ||
                 ts.forEachChild(node, containsParseError);
             // If so, mark ourselves accordingly.
             if (thisNodeOrAnySubNodesHasError) {
-                node.flags |= 4194304 /* ThisNodeOrAnySubNodesHasError */;
+                node.flags |= 131072 /* ThisNodeOrAnySubNodesHasError */;
             }
             // Also mark that we've propagated the child information to this node.  This way we can
             // always consult the bit directly on this node without needing to check its children
             // again.
-            node.flags |= 8388608 /* HasAggregatedChildData */;
+            node.flags |= 262144 /* HasAggregatedChildData */;
         }
     }
     function getSourceFileOfNode(node) {
@@ -6774,6 +6790,10 @@ var ts;
         return false;
     }
     ts.isExternalModuleAugmentation = isExternalModuleAugmentation;
+    function isEffectiveExternalModule(node, compilerOptions) {
+        return ts.isExternalModule(node) || compilerOptions.isolatedModules;
+    }
+    ts.isEffectiveExternalModule = isEffectiveExternalModule;
     function isBlockScope(node, parentNode) {
         switch (node.kind) {
             case 261 /* SourceFile */:
@@ -7601,7 +7621,7 @@ var ts;
     }
     ts.isSourceFileJavaScript = isSourceFileJavaScript;
     function isInJavaScriptFile(node) {
-        return node && !!(node.flags & 2097152 /* JavaScriptFile */);
+        return node && !!(node.flags & 65536 /* JavaScriptFile */);
     }
     ts.isInJavaScriptFile = isInJavaScriptFile;
     /**
@@ -7867,7 +7887,7 @@ var ts;
     }
     ts.hasDeclaredRestParameter = hasDeclaredRestParameter;
     function isRestParameter(node) {
-        if (node && (node.flags & 2097152 /* JavaScriptFile */)) {
+        if (node && (node.flags & 65536 /* JavaScriptFile */)) {
             if (node.type && node.type.kind === 275 /* JSDocVariadicType */ ||
                 ts.forEach(getJSDocParameterTags(node), function (t) { return t.typeExpression && t.typeExpression.type.kind === 275 /* JSDocVariadicType */; })) {
                 return true;
@@ -14335,7 +14355,7 @@ var ts;
         // Share a single scanner across all calls to parse a source file.  This helps speed things
         // up by avoiding the cost of creating/compiling scanners over and over again.
         var scanner = ts.createScanner(5 /* Latest */, /*skipTrivia*/ true);
-        var disallowInAndDecoratorContext = 65536 /* DisallowInContext */ | 262144 /* DecoratorContext */;
+        var disallowInAndDecoratorContext = 2048 /* DisallowInContext */ | 8192 /* DecoratorContext */;
         // capture constructors in 'initializeState' to avoid null checks
         var NodeConstructor;
         var TokenConstructor;
@@ -14459,7 +14479,7 @@ var ts;
             identifiers = ts.createMap();
             identifierCount = 0;
             nodeCount = 0;
-            contextFlags = scriptKind === 1 /* JS */ || scriptKind === 2 /* JSX */ ? 2097152 /* JavaScriptFile */ : 0 /* None */;
+            contextFlags = scriptKind === 1 /* JS */ || scriptKind === 2 /* JSX */ ? 65536 /* JavaScriptFile */ : 0 /* None */;
             parseErrorBeforeNextFinishedNode = false;
             // Initialize and prime the scanner before parsing the source elements.
             scanner.setText(sourceText);
@@ -14567,16 +14587,16 @@ var ts;
             }
         }
         function setDisallowInContext(val) {
-            setContextFlag(val, 65536 /* DisallowInContext */);
+            setContextFlag(val, 2048 /* DisallowInContext */);
         }
         function setYieldContext(val) {
-            setContextFlag(val, 131072 /* YieldContext */);
+            setContextFlag(val, 4096 /* YieldContext */);
         }
         function setDecoratorContext(val) {
-            setContextFlag(val, 262144 /* DecoratorContext */);
+            setContextFlag(val, 8192 /* DecoratorContext */);
         }
         function setAwaitContext(val) {
-            setContextFlag(val, 524288 /* AwaitContext */);
+            setContextFlag(val, 16384 /* AwaitContext */);
         }
         function doOutsideOfContext(context, func) {
             // contextFlagsToClear will contain only the context flags that are
@@ -14617,40 +14637,40 @@ var ts;
             return func();
         }
         function allowInAnd(func) {
-            return doOutsideOfContext(65536 /* DisallowInContext */, func);
+            return doOutsideOfContext(2048 /* DisallowInContext */, func);
         }
         function disallowInAnd(func) {
-            return doInsideOfContext(65536 /* DisallowInContext */, func);
+            return doInsideOfContext(2048 /* DisallowInContext */, func);
         }
         function doInYieldContext(func) {
-            return doInsideOfContext(131072 /* YieldContext */, func);
+            return doInsideOfContext(4096 /* YieldContext */, func);
         }
         function doInDecoratorContext(func) {
-            return doInsideOfContext(262144 /* DecoratorContext */, func);
+            return doInsideOfContext(8192 /* DecoratorContext */, func);
         }
         function doInAwaitContext(func) {
-            return doInsideOfContext(524288 /* AwaitContext */, func);
+            return doInsideOfContext(16384 /* AwaitContext */, func);
         }
         function doOutsideOfAwaitContext(func) {
-            return doOutsideOfContext(524288 /* AwaitContext */, func);
+            return doOutsideOfContext(16384 /* AwaitContext */, func);
         }
         function doInYieldAndAwaitContext(func) {
-            return doInsideOfContext(131072 /* YieldContext */ | 524288 /* AwaitContext */, func);
+            return doInsideOfContext(4096 /* YieldContext */ | 16384 /* AwaitContext */, func);
         }
         function inContext(flags) {
             return (contextFlags & flags) !== 0;
         }
         function inYieldContext() {
-            return inContext(131072 /* YieldContext */);
+            return inContext(4096 /* YieldContext */);
         }
         function inDisallowInContext() {
-            return inContext(65536 /* DisallowInContext */);
+            return inContext(2048 /* DisallowInContext */);
         }
         function inDecoratorContext() {
-            return inContext(262144 /* DecoratorContext */);
+            return inContext(8192 /* DecoratorContext */);
         }
         function inAwaitContext() {
-            return inContext(524288 /* AwaitContext */);
+            return inContext(16384 /* AwaitContext */);
         }
         function parseErrorAtCurrentToken(message, arg0) {
             var start = scanner.getTokenPos();
@@ -14854,7 +14874,7 @@ var ts;
             // flag so that we don't mark any subsequent nodes.
             if (parseErrorBeforeNextFinishedNode) {
                 parseErrorBeforeNextFinishedNode = false;
-                node.flags |= 1048576 /* ThisNodeHasError */;
+                node.flags |= 32768 /* ThisNodeHasError */;
             }
             return node;
         }
@@ -15248,7 +15268,7 @@ var ts;
             // differently depending on what mode it is in.
             //
             // This also applies to all our other context flags as well.
-            var nodeContextFlags = node.flags & 3080192 /* ContextFlags */;
+            var nodeContextFlags = node.flags & 96256 /* ContextFlags */;
             if (nodeContextFlags !== contextFlags) {
                 return undefined;
             }
@@ -16253,7 +16273,7 @@ var ts;
         function parseType() {
             // The rules about 'yield' only apply to actual code/expression contexts.  They don't
             // apply to 'type' contexts.  So we disable these parameters here before moving on.
-            return doOutsideOfContext(655360 /* TypeExcludesFlags */, parseTypeWorker);
+            return doOutsideOfContext(20480 /* TypeExcludesFlags */, parseTypeWorker);
         }
         function parseTypeWorker() {
             if (isStartOfFunctionType()) {
@@ -18363,7 +18383,7 @@ var ts;
             // The checker may still error in the static case to explicitly disallow the yield expression.
             property.initializer = ts.hasModifier(property, 32 /* Static */)
                 ? allowInAnd(parseNonParameterInitializer)
-                : doOutsideOfContext(131072 /* YieldContext */ | 65536 /* DisallowInContext */, parseNonParameterInitializer);
+                : doOutsideOfContext(4096 /* YieldContext */ | 2048 /* DisallowInContext */, parseNonParameterInitializer);
             parseSemicolon();
             return addJSDocComment(finishNode(property));
         }
@@ -20844,8 +20864,7 @@ var ts;
                 hasExplicitReturn = false;
                 bindChildren(node);
                 // Reset all reachability check related flags on node (for incremental scenarios)
-                // Reset all emit helper flags on node (for incremental scenarios)
-                node.flags &= ~64896 /* ReachabilityAndEmitFlags */;
+                node.flags &= ~1408 /* ReachabilityAndEmitFlags */;
                 if (!(currentFlow.flags & 1 /* Unreachable */) && containerFlags & 8 /* IsFunctionLike */ && ts.nodeIsPresent(node.body)) {
                     node.flags |= 128 /* HasImplicitReturn */;
                     if (hasExplicitReturn)
@@ -22158,9 +22177,6 @@ var ts;
                     return bindParameter(node);
                 case 223 /* VariableDeclaration */:
                 case 174 /* BindingElement */:
-                    if (node.dotDotDotToken && node.parent.kind === 172 /* ObjectBindingPattern */) {
-                        emitFlags |= 32768 /* HasRestAttribute */;
-                    }
                     return bindVariableDeclarationOrBindingElement(node);
                 case 147 /* PropertyDeclaration */:
                 case 146 /* PropertySignature */:
@@ -22187,7 +22203,6 @@ var ts;
                         }
                         root = root.parent;
                     }
-                    emitFlags |= hasRest ? 32768 /* HasRestAttribute */ : 16384 /* HasSpreadAttribute */;
                     return;
                 case 153 /* CallSignature */:
                 case 154 /* ConstructSignature */:
@@ -22413,14 +22428,6 @@ var ts;
             }
         }
         function bindClassLikeDeclaration(node) {
-            if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
-                if (ts.getClassExtendsHeritageClauseElement(node) !== undefined) {
-                    emitFlags |= 1024 /* HasClassExtends */;
-                }
-                if (ts.nodeIsDecorated(node)) {
-                    emitFlags |= 2048 /* HasDecorators */;
-                }
-            }
             if (node.kind === 226 /* ClassDeclaration */) {
                 bindBlockScopedDeclaration(node, 32 /* Class */, 899519 /* ClassExcludes */);
             }
@@ -22483,11 +22490,6 @@ var ts;
             }
         }
         function bindParameter(node) {
-            if (!ts.isDeclarationFile(file) &&
-                !ts.isInAmbientContext(node) &&
-                ts.nodeIsDecorated(node)) {
-                emitFlags |= (2048 /* HasDecorators */ | 4096 /* HasParamDecorators */);
-            }
             if (inStrictMode) {
                 // It is a SyntaxError if the identifier eval or arguments appears within a FormalParameterList of a
                 // strict mode FunctionLikeDeclaration or FunctionExpression(13.1)
@@ -22509,7 +22511,7 @@ var ts;
         function bindFunctionDeclaration(node) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192 /* HasAsyncFunctions */;
+                    emitFlags |= 1024 /* HasAsyncFunctions */;
                 }
             }
             checkStrictModeFunctionName(node);
@@ -22524,7 +22526,7 @@ var ts;
         function bindFunctionExpression(node) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192 /* HasAsyncFunctions */;
+                    emitFlags |= 1024 /* HasAsyncFunctions */;
                 }
             }
             if (currentFlow) {
@@ -22537,10 +22539,7 @@ var ts;
         function bindPropertyOrMethodOrAccessor(node, symbolFlags, symbolExcludes) {
             if (!ts.isDeclarationFile(file) && !ts.isInAmbientContext(node)) {
                 if (ts.isAsyncFunctionLike(node)) {
-                    emitFlags |= 8192 /* HasAsyncFunctions */;
-                }
-                if (ts.nodeIsDecorated(node)) {
-                    emitFlags |= 2048 /* HasDecorators */;
+                    emitFlags |= 1024 /* HasAsyncFunctions */;
                 }
             }
             if (currentFlow && ts.isObjectLiteralOrClassExpressionMethod(node)) {
@@ -24132,6 +24131,8 @@ var ts;
         // is because diagnostics can be quite expensive, and we want to allow hosts to bail out if
         // they no longer need the information (for example, if the user started editing again).
         var cancellationToken;
+        var requestedExternalEmitHelpers;
+        var externalHelpersModule;
         var Symbol = ts.objectAllocator.getSymbolConstructor();
         var Type = ts.objectAllocator.getTypeConstructor();
         var Signature = ts.objectAllocator.getSignatureConstructor();
@@ -26872,7 +26873,13 @@ var ts;
             return name.kind === 142 /* ComputedPropertyName */ && !ts.isStringOrNumericLiteral(name.expression);
         }
         function getRestType(source, properties, symbol) {
-            ts.Debug.assert(!!(source.flags & 32768 /* Object */), "Rest types only support object types right now.");
+            source = filterType(source, function (t) { return !(t.flags & 6144 /* Nullable */); });
+            if (source.flags & 8192 /* Never */) {
+                return emptyObjectType;
+            }
+            if (source.flags & 65536 /* Union */) {
+                return mapType(source, function (t) { return getRestType(t, properties, symbol); });
+            }
             var members = ts.createMap();
             var names = ts.createMap();
             for (var _i = 0, properties_2 = properties; _i < properties_2.length; _i++) {
@@ -26913,7 +26920,7 @@ var ts;
             var type;
             if (pattern.kind === 172 /* ObjectBindingPattern */) {
                 if (declaration.dotDotDotToken) {
-                    if (!(parentType.flags & 32768 /* Object */)) {
+                    if (!isValidSpreadType(parentType)) {
                         error(declaration, ts.Diagnostics.Rest_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
@@ -27003,7 +27010,7 @@ var ts;
         }
         // Return the inferred type for a variable, parameter, or property declaration
         function getTypeForVariableLikeDeclaration(declaration, includeOptionality) {
-            if (declaration.flags & 2097152 /* JavaScriptFile */) {
+            if (declaration.flags & 65536 /* JavaScriptFile */) {
                 // If this is a variable in a JavaScript file, then use the JSDoc type (if it has
                 // one as its type), otherwise fallback to the below standard TS codepaths to
                 // try to figure it out.
@@ -27032,7 +27039,7 @@ var ts;
             if (declaration.type) {
                 return addOptionality(getTypeFromTypeNode(declaration.type), /*optional*/ declaration.questionToken && includeOptionality);
             }
-            if ((compilerOptions.noImplicitAny || declaration.flags & 2097152 /* JavaScriptFile */) &&
+            if ((compilerOptions.noImplicitAny || declaration.flags & 65536 /* JavaScriptFile */) &&
                 declaration.kind === 223 /* VariableDeclaration */ && !ts.isBindingPattern(declaration.name) &&
                 !(ts.getCombinedModifierFlags(declaration) & 1 /* Export */) && !ts.isInAmbientContext(declaration)) {
                 // If --noImplicitAny is on or the declaration is in a Javascript file,
@@ -27109,14 +27116,19 @@ var ts;
         // Return the type implied by an object binding pattern
         function getTypeFromObjectBindingPattern(pattern, includePatternInType, reportErrors) {
             var members = ts.createMap();
+            var stringIndexInfo;
             var hasComputedProperties = false;
             ts.forEach(pattern.elements, function (e) {
                 var name = e.propertyName || e.name;
-                if (isComputedNonLiteralName(name) || e.dotDotDotToken) {
-                    // do not include computed properties or rests in the implied type
+                if (isComputedNonLiteralName(name)) {
+                    // do not include computed properties in the implied type
                     hasComputedProperties = true;
                     return;
                 }
+                if (e.dotDotDotToken) {
+                    stringIndexInfo = createIndexInfo(anyType, /*isReadonly*/ false);
+                    return;
+                }
                 var text = ts.getTextOfPropertyName(name);
                 var flags = 4 /* Property */ | 67108864 /* Transient */ | (e.initializer ? 536870912 /* Optional */ : 0);
                 var symbol = createSymbol(flags, text);
@@ -27124,7 +27136,7 @@ var ts;
                 symbol.bindingElement = e;
                 members[symbol.name] = symbol;
             });
-            var result = createAnonymousType(undefined, members, emptyArray, emptyArray, undefined, undefined);
+            var result = createAnonymousType(undefined, members, emptyArray, emptyArray, stringIndexInfo, undefined);
             if (includePatternInType) {
                 result.pattern = pattern;
             }
@@ -27215,7 +27227,7 @@ var ts;
                 if (declaration.kind === 240 /* ExportAssignment */) {
                     return links.type = checkExpression(declaration.expression);
                 }
-                if (declaration.flags & 2097152 /* JavaScriptFile */ && declaration.kind === 286 /* JSDocPropertyTag */ && declaration.typeExpression) {
+                if (declaration.flags & 65536 /* JavaScriptFile */ && declaration.kind === 286 /* JSDocPropertyTag */ && declaration.typeExpression) {
                     return links.type = getTypeFromTypeNode(declaration.typeExpression.type);
                 }
                 // Handle variable, parameter or property
@@ -27231,7 +27243,7 @@ var ts;
                 if (declaration.kind === 192 /* BinaryExpression */ ||
                     declaration.kind === 177 /* PropertyAccessExpression */ && declaration.parent.kind === 192 /* BinaryExpression */) {
                     // Use JS Doc type if present on parent expression statement
-                    if (declaration.flags & 2097152 /* JavaScriptFile */) {
+                    if (declaration.flags & 65536 /* JavaScriptFile */) {
                         var jsdocType = ts.getJSDocType(declaration.parent);
                         if (jsdocType) {
                             return links.type = getTypeFromTypeNode(jsdocType);
@@ -27287,7 +27299,7 @@ var ts;
             if (!links.type) {
                 var getter = ts.getDeclarationOfKind(symbol, 151 /* GetAccessor */);
                 var setter = ts.getDeclarationOfKind(symbol, 152 /* SetAccessor */);
-                if (getter && getter.flags & 2097152 /* JavaScriptFile */) {
+                if (getter && getter.flags & 65536 /* JavaScriptFile */) {
                     var jsDocType = getTypeForVariableLikeDeclarationFromJSDocComment(getter);
                     if (jsDocType) {
                         return links.type = jsDocType;
@@ -28252,7 +28264,7 @@ var ts;
                     var isomorphicProp = isomorphicType && getPropertyOfType(isomorphicType, propName);
                     var isOptional = templateOptional || !!(isomorphicProp && isomorphicProp.flags & 536870912 /* Optional */);
                     var prop = createSymbol(4 /* Property */ | 67108864 /* Transient */ | (isOptional ? 536870912 /* Optional */ : 0), propName);
-                    prop.type = addOptionality(propType, isOptional);
+                    prop.type = propType;
                     prop.isReadonly = templateReadonly || isomorphicProp && isReadonlySymbol(isomorphicProp);
                     members[propName] = prop;
                 }
@@ -28273,7 +28285,7 @@ var ts;
         function getTemplateTypeFromMappedType(type) {
             return type.templateType ||
                 (type.templateType = type.declaration.type ?
-                    instantiateType(getTypeFromTypeNode(type.declaration.type), type.mapper || identityMapper) :
+                    instantiateType(addOptionality(getTypeFromTypeNode(type.declaration.type), !!type.declaration.questionToken), type.mapper || identityMapper) :
                     unknownType);
         }
         function getIsomorphicTypeFromMappedType(type) {
@@ -28563,7 +28575,7 @@ var ts;
             return undefined;
         }
         function getTypeParametersFromJSDocTemplate(declaration) {
-            if (declaration.flags & 2097152 /* JavaScriptFile */) {
+            if (declaration.flags & 65536 /* JavaScriptFile */) {
                 var templateTag = ts.getJSDocTemplateTag(declaration);
                 if (templateTag) {
                     return getTypeParametersFromDeclaration(templateTag.typeParameters);
@@ -28593,7 +28605,7 @@ var ts;
             return result;
         }
         function isJSDocOptionalParameter(node) {
-            if (node.flags & 2097152 /* JavaScriptFile */) {
+            if (node.flags & 65536 /* JavaScriptFile */) {
                 if (node.type && node.type.kind === 273 /* JSDocOptionalType */) {
                     return true;
                 }
@@ -28729,7 +28741,7 @@ var ts;
             else if (declaration.type) {
                 return getTypeFromTypeNode(declaration.type);
             }
-            if (declaration.flags & 2097152 /* JavaScriptFile */) {
+            if (declaration.flags & 65536 /* JavaScriptFile */) {
                 var type = getReturnTypeFromJSDocComment(declaration);
                 if (type && type !== unknownType) {
                     return type;
@@ -29611,7 +29623,7 @@ var ts;
             }
             var mapper = createUnaryTypeMapper(getTypeParameterFromMappedType(type), indexType);
             var templateMapper = type.mapper ? combineTypeMappers(type.mapper, mapper) : mapper;
-            return addOptionality(instantiateType(getTemplateTypeFromMappedType(type), templateMapper), !!type.declaration.questionToken);
+            return instantiateType(getTemplateTypeFromMappedType(type), templateMapper);
         }
         function getIndexedAccessType(objectType, indexType, accessNode) {
             if (indexType.flags & 16384 /* TypeParameter */ ||
@@ -29703,10 +29715,23 @@ var ts;
          * and right = the new element to be spread.
          */
         function getSpreadType(left, right, isFromObjectLiteral) {
-            ts.Debug.assert(!!(left.flags & (32768 /* Object */ | 1 /* Any */)) && !!(right.flags & (32768 /* Object */ | 1 /* Any */)), "Only object types may be spread.");
             if (left.flags & 1 /* Any */ || right.flags & 1 /* Any */) {
                 return anyType;
             }
+            left = filterType(left, function (t) { return !(t.flags & 6144 /* Nullable */); });
+            if (left.flags & 8192 /* Never */) {
+                return right;
+            }
+            right = filterType(right, function (t) { return !(t.flags & 6144 /* Nullable */); });
+            if (right.flags & 8192 /* Never */) {
+                return left;
+            }
+            if (left.flags & 65536 /* Union */) {
+                return mapType(left, function (t) { return getSpreadType(t, right, isFromObjectLiteral); });
+            }
+            if (right.flags & 65536 /* Union */) {
+                return mapType(right, function (t) { return getSpreadType(left, t, isFromObjectLiteral); });
+            }
             var members = ts.createMap();
             var skippedPrivateMembers = ts.createMap();
             var stringIndexInfo;
@@ -31872,6 +31897,8 @@ var ts;
             var typeInferences = createTypeInferencesObject();
             var typeInferencesArray = [typeInferences];
             var templateType = getTemplateTypeFromMappedType(target);
+            var readonlyMask = target.declaration.readonlyToken ? false : true;
+            var optionalMask = target.declaration.questionToken ? 0 : 536870912 /* Optional */;
             var properties = getPropertiesOfType(source);
             var members = createSymbolTable(properties);
             var hasInferredTypes = false;
@@ -31879,10 +31906,10 @@ var ts;
                 var prop = properties_4[_i];
                 var inferredPropType = inferTargetType(getTypeOfSymbol(prop));
                 if (inferredPropType) {
-                    var inferredProp = createSymbol(4 /* Property */ | 67108864 /* Transient */ | prop.flags & 536870912 /* Optional */, prop.name);
+                    var inferredProp = createSymbol(4 /* Property */ | 67108864 /* Transient */ | prop.flags & optionalMask, prop.name);
                     inferredProp.declarations = prop.declarations;
                     inferredProp.type = inferredPropType;
-                    inferredProp.isReadonly = isReadonlySymbol(prop);
+                    inferredProp.isReadonly = readonlyMask && isReadonlySymbol(prop);
                     members[prop.name] = inferredProp;
                     hasInferredTypes = true;
                 }
@@ -31891,7 +31918,7 @@ var ts;
             if (indexInfo) {
                 var inferredIndexType = inferTargetType(indexInfo.type);
                 if (inferredIndexType) {
-                    indexInfo = createIndexInfo(inferredIndexType, indexInfo.isReadonly);
+                    indexInfo = createIndexInfo(inferredIndexType, readonlyMask && indexInfo.isReadonly);
                     hasInferredTypes = true;
                 }
             }
@@ -33414,7 +33441,7 @@ var ts;
                         error(node, ts.Diagnostics.The_arguments_object_cannot_be_referenced_in_an_async_function_or_method_in_ES3_and_ES5_Consider_using_a_standard_function_or_method);
                     }
                 }
-                if (node.flags & 524288 /* AwaitContext */) {
+                if (node.flags & 16384 /* AwaitContext */) {
                     getNodeLinks(container).flags |= 8192 /* CaptureArguments */;
                 }
                 return getTypeOfSymbol(symbol);
@@ -34604,7 +34631,7 @@ var ts;
                         if (impliedProp) {
                             prop.flags |= impliedProp.flags & 536870912 /* Optional */;
                         }
-                        else if (!compilerOptions.suppressExcessPropertyErrors) {
+                        else if (!compilerOptions.suppressExcessPropertyErrors && !getIndexInfoOfType(contextualType, 0 /* String */)) {
                             error(memberDecl.name, ts.Diagnostics.Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1, symbolToString(member), typeToString(contextualType));
                         }
                     }
@@ -34618,6 +34645,9 @@ var ts;
                     member = prop;
                 }
                 else if (memberDecl.kind === 259 /* SpreadAssignment */) {
+                    if (languageVersion < 5 /* ESNext */) {
+                        checkExternalEmitHelpers(memberDecl, 2 /* Assign */);
+                    }
                     if (propertiesArray.length > 0) {
                         spread = getSpreadType(spread, createObjectLiteralType(), /*isFromObjectLiteral*/ true);
                         propertiesArray = [];
@@ -34627,7 +34657,7 @@ var ts;
                         typeFlags = 0;
                     }
                     var type = checkExpression(memberDecl.expression);
-                    if (!(type.flags & (32768 /* Object */ | 1 /* Any */))) {
+                    if (!isValidSpreadType(type)) {
                         error(memberDecl, ts.Diagnostics.Spread_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
@@ -34699,6 +34729,11 @@ var ts;
                 return result;
             }
         }
+        function isValidSpreadType(type) {
+            return !!(type.flags & (1 /* Any */ | 4096 /* Null */ | 2048 /* Undefined */) ||
+                type.flags & 32768 /* Object */ && !isGenericMappedType(type) ||
+                type.flags & 196608 /* UnionOrIntersection */ && !ts.forEach(type.types, function (t) { return !isValidSpreadType(t); }));
+        }
         function checkJsxSelfClosingElement(node) {
             checkJsxOpeningLikeElement(node);
             return jsxElementType || anyType;
@@ -34788,6 +34823,9 @@ var ts;
             return exprType;
         }
         function checkJsxSpreadAttribute(node, elementAttributesType, nameTable) {
+            if (compilerOptions.jsx === 2 /* React */) {
+                checkExternalEmitHelpers(node, 2 /* Assign */);
+            }
             var type = checkExpression(node.expression);
             var props = getPropertiesOfType(type);
             for (var _i = 0, props_2 = props; _i < props_2.length; _i++) {
@@ -37085,7 +37123,7 @@ var ts;
         function checkAwaitExpression(node) {
             // Grammar checking
             if (produceDiagnostics) {
-                if (!(node.flags & 524288 /* AwaitContext */)) {
+                if (!(node.flags & 16384 /* AwaitContext */)) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.await_expression_is_only_allowed_within_an_async_function);
                 }
                 if (isInParameterInitializerBeforeContainingFunction(node)) {
@@ -37262,6 +37300,9 @@ var ts;
                 }
             }
             else if (property.kind === 259 /* SpreadAssignment */) {
+                if (languageVersion < 5 /* ESNext */) {
+                    checkExternalEmitHelpers(property, 4 /* Rest */);
+                }
                 var nonRestNames = [];
                 if (allProperties) {
                     for (var i = 0; i < allProperties.length - 1; i++) {
@@ -37658,7 +37699,7 @@ var ts;
         function checkYieldExpression(node) {
             // Grammar checking
             if (produceDiagnostics) {
-                if (!(node.flags & 131072 /* YieldContext */) || isYieldExpressionInClass(node)) {
+                if (!(node.flags & 4096 /* YieldContext */) || isYieldExpressionInClass(node)) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.A_yield_expression_is_only_allowed_in_a_generator_body);
                 }
                 if (isInParameterInitializerBeforeContainingFunction(node)) {
@@ -38088,6 +38129,12 @@ var ts;
                 node.kind === 154 /* ConstructSignature */) {
                 checkGrammarFunctionLikeDeclaration(node);
             }
+            if (ts.isAsyncFunctionLike(node) && languageVersion < 4 /* ES2017 */) {
+                checkExternalEmitHelpers(node, 64 /* Awaiter */);
+                if (languageVersion < 2 /* ES2015 */) {
+                    checkExternalEmitHelpers(node, 128 /* Generator */);
+                }
+            }
             checkTypeParameters(node.typeParameters);
             ts.forEach(node.parameters, checkParameter);
             if (node.type) {
@@ -39088,7 +39135,13 @@ var ts;
             if (!compilerOptions.experimentalDecorators) {
                 error(node, ts.Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning);
             }
+            var firstDecorator = node.decorators[0];
+            checkExternalEmitHelpers(firstDecorator, 8 /* Decorate */);
+            if (node.kind === 144 /* Parameter */) {
+                checkExternalEmitHelpers(firstDecorator, 32 /* Param */);
+            }
             if (compilerOptions.emitDecoratorMetadata) {
+                checkExternalEmitHelpers(firstDecorator, 16 /* Metadata */);
                 // we only need to perform these checks if we are emitting serialized type metadata for the target of a decorator.
                 switch (node.kind) {
                     case 226 /* ClassDeclaration */:
@@ -39441,7 +39494,7 @@ var ts;
             }
         }
         function checkCollisionWithGlobalPromiseInGeneratedCode(node, name) {
-            if (!needCollisionCheckForIdentifier(node, name, "Promise")) {
+            if (languageVersion >= 4 /* ES2017 */ || !needCollisionCheckForIdentifier(node, name, "Promise")) {
                 return;
             }
             // Uninstantiated modules shouldnt do this check
@@ -39450,7 +39503,7 @@ var ts;
             }
             // In case of variable declaration, node.parent is variable statement so look at the variable statement's parent
             var parent = getDeclarationContainer(node);
-            if (parent.kind === 261 /* SourceFile */ && ts.isExternalOrCommonJsModule(parent) && parent.flags & 8192 /* HasAsyncFunctions */) {
+            if (parent.kind === 261 /* SourceFile */ && ts.isExternalOrCommonJsModule(parent) && parent.flags & 1024 /* HasAsyncFunctions */) {
                 // If the declaration happens to be in external module, report error that Promise is a reserved identifier.
                 error(name, ts.Diagnostics.Duplicate_identifier_0_Compiler_reserves_name_1_in_top_level_scope_of_a_module_containing_async_functions, ts.declarationNameToString(name), ts.declarationNameToString(name));
             }
@@ -39598,6 +39651,9 @@ var ts;
                 }
             }
             if (node.kind === 174 /* BindingElement */) {
+                if (node.parent.kind === 172 /* ObjectBindingPattern */ && languageVersion < 5 /* ESNext */) {
+                    checkExternalEmitHelpers(node, 4 /* Rest */);
+                }
                 // check computed properties inside property names of binding elements
                 if (node.propertyName && node.propertyName.kind === 142 /* ComputedPropertyName */) {
                     checkComputedPropertyName(node.propertyName);
@@ -40136,7 +40192,7 @@ var ts;
         function checkWithStatement(node) {
             // Grammar checking for withStatement
             if (!checkGrammarStatementInAmbientContext(node)) {
-                if (node.flags & 524288 /* AwaitContext */) {
+                if (node.flags & 16384 /* AwaitContext */) {
                     grammarErrorOnFirstToken(node, ts.Diagnostics.with_statements_are_not_allowed_in_an_async_function_block);
                 }
             }
@@ -40407,6 +40463,9 @@ var ts;
             checkClassForDuplicateDeclarations(node);
             var baseTypeNode = ts.getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
+                if (languageVersion < 2 /* ES2015 */) {
+                    checkExternalEmitHelpers(baseTypeNode.parent, 1 /* Extends */);
+                }
                 var baseTypes = getBaseTypes(type);
                 if (baseTypes.length && produceDiagnostics) {
                     var baseType_1 = baseTypes[0];
@@ -42606,8 +42665,6 @@ var ts;
             }
             // Initialize global symbol table
             var augmentations;
-            var requestedExternalEmitHelpers = 0;
-            var firstFileRequestingExternalHelpers;
             for (var _b = 0, _c = host.getSourceFiles(); _b < _c.length; _b++) {
                 var file = _c[_b];
                 if (!ts.isExternalOrCommonJsModule(file)) {
@@ -42628,15 +42685,6 @@ var ts;
                         }
                     }
                 }
-                if ((compilerOptions.isolatedModules || ts.isExternalModule(file)) && !file.isDeclarationFile) {
-                    var fileRequestedExternalEmitHelpers = file.flags & 64512 /* EmitHelperFlags */;
-                    if (fileRequestedExternalEmitHelpers) {
-                        requestedExternalEmitHelpers |= fileRequestedExternalEmitHelpers;
-                        if (firstFileRequestingExternalHelpers === undefined) {
-                            firstFileRequestingExternalHelpers = file;
-                        }
-                    }
-                }
             }
             if (augmentations) {
                 // merge module augmentations.
@@ -42695,50 +42743,46 @@ var ts;
             var symbol = getGlobalSymbol("ReadonlyArray", 793064 /* Type */, /*diagnostic*/ undefined);
             globalReadonlyArrayType = symbol && getTypeOfGlobalSymbol(symbol, /*arity*/ 1);
             anyReadonlyArrayType = globalReadonlyArrayType ? createTypeFromGenericGlobalType(globalReadonlyArrayType, [anyType]) : anyArrayType;
-            // If we have specified that we are importing helpers, we should report global
-            // errors if we cannot resolve the helpers external module, or if it does not have
-            // the necessary helpers exported.
-            if (compilerOptions.importHelpers && firstFileRequestingExternalHelpers) {
-                // Find the first reference to the helpers module.
-                var helpersModule = resolveExternalModule(firstFileRequestingExternalHelpers, ts.externalHelpersModuleNameText, ts.Diagnostics.Cannot_find_module_0, 
-                /*errorNode*/ undefined);
-                // If we found the module, report errors if it does not have the necessary exports.
-                if (helpersModule) {
-                    var exports = helpersModule.exports;
-                    if (requestedExternalEmitHelpers & 1024 /* HasClassExtends */ && languageVersion < 2 /* ES2015 */) {
-                        verifyHelperSymbol(exports, "__extends", 107455 /* Value */);
-                    }
-                    if (requestedExternalEmitHelpers & 16384 /* HasSpreadAttribute */ &&
-                        (languageVersion < 5 /* ESNext */ || compilerOptions.jsx === 2 /* React */)) {
-                        verifyHelperSymbol(exports, "__assign", 107455 /* Value */);
-                    }
-                    if (languageVersion < 5 /* ESNext */ && requestedExternalEmitHelpers & 32768 /* HasRestAttribute */) {
-                        verifyHelperSymbol(exports, "__rest", 107455 /* Value */);
-                    }
-                    if (requestedExternalEmitHelpers & 2048 /* HasDecorators */) {
-                        verifyHelperSymbol(exports, "__decorate", 107455 /* Value */);
-                        if (compilerOptions.emitDecoratorMetadata) {
-                            verifyHelperSymbol(exports, "__metadata", 107455 /* Value */);
-                        }
-                    }
-                    if (requestedExternalEmitHelpers & 4096 /* HasParamDecorators */) {
-                        verifyHelperSymbol(exports, "__param", 107455 /* Value */);
-                    }
-                    if (requestedExternalEmitHelpers & 8192 /* HasAsyncFunctions */) {
-                        verifyHelperSymbol(exports, "__awaiter", 107455 /* Value */);
-                        if (languageVersion < 2 /* ES2015 */) {
-                            verifyHelperSymbol(exports, "__generator", 107455 /* Value */);
+        }
+        function checkExternalEmitHelpers(location, helpers) {
+            if ((requestedExternalEmitHelpers & helpers) !== helpers && compilerOptions.importHelpers) {
+                var sourceFile = ts.getSourceFileOfNode(location);
+                if (ts.isEffectiveExternalModule(sourceFile, compilerOptions)) {
+                    var helpersModule = resolveHelpersModule(sourceFile, location);
+                    if (helpersModule !== unknownSymbol) {
+                        var uncheckedHelpers = helpers & ~requestedExternalEmitHelpers;
+                        for (var helper = 1 /* FirstEmitHelper */; helper <= 128 /* LastEmitHelper */; helper <<= 1) {
+                            if (uncheckedHelpers & helper) {
+                                var name_27 = getHelperName(helper);
+                                var symbol = getSymbol(helpersModule.exports, ts.escapeIdentifier(name_27), 107455 /* Value */);
+                                if (!symbol) {
+                                    error(location, ts.Diagnostics.This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1, ts.externalHelpersModuleNameText, name_27);
+                                }
+                            }
                         }
                     }
+                    requestedExternalEmitHelpers |= helpers;
                 }
             }
         }
-        function verifyHelperSymbol(symbols, name, meaning) {
-            var symbol = getSymbol(symbols, ts.escapeIdentifier(name), meaning);
-            if (!symbol) {
-                error(/*location*/ undefined, ts.Diagnostics.Module_0_has_no_exported_member_1, ts.externalHelpersModuleNameText, name);
+        function getHelperName(helper) {
+            switch (helper) {
+                case 1 /* Extends */: return "__extends";
+                case 2 /* Assign */: return "__assign";
+                case 4 /* Rest */: return "__rest";
+                case 8 /* Decorate */: return "__decorate";
+                case 16 /* Metadata */: return "__metadata";
+                case 32 /* Param */: return "__param";
+                case 64 /* Awaiter */: return "__awaiter";
+                case 128 /* Generator */: return "__generator";
             }
         }
+        function resolveHelpersModule(node, errorNode) {
+            if (!externalHelpersModule) {
+                externalHelpersModule = resolveExternalModule(node, ts.externalHelpersModuleNameText, ts.Diagnostics.This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found, errorNode) || unknownSymbol;
+            }
+            return externalHelpersModule;
+        }
         function createInstantiatedPromiseLikeType() {
             var promiseLikeType = getGlobalPromiseLikeType();
             if (promiseLikeType !== emptyGenericType) {
@@ -43273,10 +43317,10 @@ var ts;
                 if (prop.kind === 259 /* SpreadAssignment */) {
                     continue;
                 }
-                var name_27 = prop.name;
-                if (name_27.kind === 142 /* ComputedPropertyName */) {
+                var name_28 = prop.name;
+                if (name_28.kind === 142 /* ComputedPropertyName */) {
                     // If the name is not a ComputedPropertyName, the grammar checking will skip it
-                    checkGrammarComputedPropertyName(name_27);
+                    checkGrammarComputedPropertyName(name_28);
                 }
                 if (prop.kind === 258 /* ShorthandPropertyAssignment */ && !inDestructuring && prop.objectAssignmentInitializer) {
                     // having objectAssignmentInitializer is only valid in ObjectAssignmentPattern
@@ -43304,8 +43348,8 @@ var ts;
                 if (prop.kind === 257 /* PropertyAssignment */ || prop.kind === 258 /* ShorthandPropertyAssignment */) {
                     // Grammar checking for computedPropertyName and shorthandPropertyAssignment
                     checkGrammarForInvalidQuestionMark(prop.questionToken, ts.Diagnostics.An_object_member_cannot_be_declared_optional);
-                    if (name_27.kind === 8 /* NumericLiteral */) {
-                        checkGrammarNumericLiteral(name_27);
+                    if (name_28.kind === 8 /* NumericLiteral */) {
+                        checkGrammarNumericLiteral(name_28);
                     }
                     currentKind = Property;
                 }
@@ -43321,7 +43365,7 @@ var ts;
                 else {
                     ts.Debug.fail("Unexpected syntax kind:" + prop.kind);
                 }
-                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_27);
+                var effectiveName = ts.getPropertyNameForPropertyNameNode(name_28);
                 if (effectiveName === undefined) {
                     continue;
                 }
@@ -43331,18 +43375,18 @@ var ts;
                 else {
                     var existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
-                        grammarErrorOnNode(name_27, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_27));
+                        grammarErrorOnNode(name_28, ts.Diagnostics.Duplicate_identifier_0, ts.getTextOfNode(name_28));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
                             seen[effectiveName] = currentKind | existingKind;
                         }
                         else {
-                            return grammarErrorOnNode(name_27, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
+                            return grammarErrorOnNode(name_28, ts.Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
                         }
                     }
                     else {
-                        return grammarErrorOnNode(name_27, ts.Diagnostics.An_object_literal_cannot_have_property_and_accessor_with_the_same_name);
+                        return grammarErrorOnNode(name_28, ts.Diagnostics.An_object_literal_cannot_have_property_and_accessor_with_the_same_name);
                     }
                 }
             }
@@ -43355,12 +43399,12 @@ var ts;
                     continue;
                 }
                 var jsxAttr = attr;
-                var name_28 = jsxAttr.name;
-                if (!seen[name_28.text]) {
-                    seen[name_28.text] = true;
+                var name_29 = jsxAttr.name;
+                if (!seen[name_29.text]) {
+                    seen[name_29.text] = true;
                 }
                 else {
-                    return grammarErrorOnNode(name_28, ts.Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
+                    return grammarErrorOnNode(name_29, ts.Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
                 }
                 var initializer = jsxAttr.initializer;
                 if (initializer && initializer.kind === 252 /* JsxExpression */ && !initializer.expression) {
@@ -44879,11 +44923,11 @@ var ts;
             }
         }
         for (var _i = 0, pendingDeclarations_1 = pendingDeclarations; _i < pendingDeclarations_1.length; _i++) {
-            var _a = pendingDeclarations_1[_i], pendingExpressions_1 = _a.pendingExpressions, name_29 = _a.name, value = _a.value, location_2 = _a.location, original = _a.original;
-            var variable = ts.createVariableDeclaration(name_29, 
+            var _a = pendingDeclarations_1[_i], pendingExpressions_1 = _a.pendingExpressions, name_30 = _a.name, value = _a.value, location_2 = _a.location, original = _a.original;
+            var variable = ts.createVariableDeclaration(name_30, 
             /*type*/ undefined, pendingExpressions_1 ? ts.inlineExpressions(ts.append(pendingExpressions_1, value)) : value, location_2);
             variable.original = original;
-            if (ts.isIdentifier(name_29)) {
+            if (ts.isIdentifier(name_30)) {
                 ts.setEmitFlags(variable, 64 /* NoNestedSourceMaps */);
             }
             ts.aggregateTransformFlags(variable);
@@ -45087,8 +45131,8 @@ var ts;
             return ts.createElementAccess(value, argumentExpression);
         }
         else {
-            var name_30 = ts.createIdentifier(ts.unescapeIdentifier(propertyName.text));
-            return ts.createPropertyAccess(value, name_30);
+            var name_31 = ts.createIdentifier(ts.unescapeIdentifier(propertyName.text));
+            return ts.createPropertyAccess(value, name_31);
         }
     }
     /**
@@ -45141,7 +45185,7 @@ var ts;
     var restHelper = {
         name: "typescript:rest",
         scoped: false,
-        text: "\n            var __rest = (this && this.__rest) || function (s, e) {\n                var t = {};\n                for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)\n                    t[p] = s[p];\n                if (typeof Object.getOwnPropertySymbols === \"function\")\n                    for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)\n                        t[p[i]] = s[p[i]];\n                return t;\n            };"
+        text: "\n            var __rest = (this && this.__rest) || function (s, e) {\n                var t = {};\n                for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)\n                    t[p] = s[p];\n                if (s != null && typeof Object.getOwnPropertySymbols === \"function\")\n                    for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)\n                        t[p[i]] = s[p[i]];\n                return t;\n            };"
     };
     /** Given value: o, propName: p, pattern: { a, b, ...p } from the original statement
      * `{ a, b, ...p } = o`, create `p = __rest(o, ["a", "b"]);`*/
@@ -46712,14 +46756,14 @@ var ts;
                 case 70 /* Identifier */:
                     // Create a clone of the name with a new parent, and treat it as if it were
                     // a source tree node for the purposes of the checker.
-                    var name_31 = ts.getMutableClone(node);
-                    name_31.flags &= ~8 /* Synthesized */;
-                    name_31.original = undefined;
-                    name_31.parent = currentScope;
+                    var name_32 = ts.getMutableClone(node);
+                    name_32.flags &= ~8 /* Synthesized */;
+                    name_32.original = undefined;
+                    name_32.parent = currentScope;
                     if (useFallback) {
-                        return ts.createLogicalAnd(ts.createStrictInequality(ts.createTypeOf(name_31), ts.createLiteral("undefined")), name_31);
+                        return ts.createLogicalAnd(ts.createStrictInequality(ts.createTypeOf(name_32), ts.createLiteral("undefined")), name_32);
                     }
-                    return name_31;
+                    return name_32;
                 case 141 /* QualifiedName */:
                     return serializeQualifiedNameAsExpression(node, useFallback);
             }
@@ -46766,7 +46810,7 @@ var ts;
                     : name.expression;
             }
             else if (ts.isIdentifier(name)) {
-                return ts.createLiteral(name.text);
+                return ts.createLiteral(ts.unescapeIdentifier(name.text));
             }
             else {
                 return ts.getSynthesizedClone(name);
@@ -47245,9 +47289,9 @@ var ts;
          */
         function isFirstEmittedDeclarationInScope(node) {
             if (currentScopeFirstDeclarationsOfName) {
-                var name_32 = node.symbol && node.symbol.name;
-                if (name_32) {
-                    return currentScopeFirstDeclarationsOfName[name_32] === node;
+                var name_33 = node.symbol && node.symbol.name;
+                if (name_33) {
+                    return currentScopeFirstDeclarationsOfName[name_33] === node;
                 }
             }
             return false;
@@ -47755,16 +47799,16 @@ var ts;
         }
         function substituteShorthandPropertyAssignment(node) {
             if (enabledSubstitutions & 2 /* NamespaceExports */) {
-                var name_33 = node.name;
-                var exportedName = trySubstituteNamespaceExportedName(name_33);
+                var name_34 = node.name;
+                var exportedName = trySubstituteNamespaceExportedName(name_34);
                 if (exportedName) {
                     // A shorthand property with an assignment initializer is probably part of a
                     // destructuring assignment
                     if (node.objectAssignmentInitializer) {
                         var initializer = ts.createAssignment(exportedName, node.objectAssignmentInitializer);
-                        return ts.createPropertyAssignment(name_33, initializer, /*location*/ node);
+                        return ts.createPropertyAssignment(name_34, initializer, /*location*/ node);
                     }
-                    return ts.createPropertyAssignment(name_33, exportedName, /*location*/ node);
+                    return ts.createPropertyAssignment(name_34, exportedName, /*location*/ node);
                 }
             }
             return node;
@@ -48379,12 +48423,12 @@ var ts;
                 return getTagName(node.openingElement);
             }
             else {
-                var name_34 = node.tagName;
-                if (ts.isIdentifier(name_34) && ts.isIntrinsicJsxName(name_34.text)) {
-                    return ts.createLiteral(name_34.text);
+                var name_35 = node.tagName;
+                if (ts.isIdentifier(name_35) && ts.isIntrinsicJsxName(name_35.text)) {
+                    return ts.createLiteral(name_35.text);
                 }
                 else {
-                    return ts.createExpressionFromEntityName(name_34);
+                    return ts.createExpressionFromEntityName(name_35);
                 }
             }
         }
@@ -49920,17 +49964,17 @@ var ts;
             }
             for (var _i = 0, _a = node.parameters; _i < _a.length; _i++) {
                 var parameter = _a[_i];
-                var name_35 = parameter.name, initializer = parameter.initializer, dotDotDotToken = parameter.dotDotDotToken;
+                var name_36 = parameter.name, initializer = parameter.initializer, dotDotDotToken = parameter.dotDotDotToken;
                 // A rest parameter cannot have a binding pattern or an initializer,
                 // so let's just ignore it.
                 if (dotDotDotToken) {
                     continue;
                 }
-                if (ts.isBindingPattern(name_35)) {
-                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name_35, initializer);
+                if (ts.isBindingPattern(name_36)) {
+                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name_36, initializer);
                 }
                 else if (initializer) {
-                    addDefaultValueAssignmentForInitializer(statements, parameter, name_35, initializer);
+                    addDefaultValueAssignmentForInitializer(statements, parameter, name_36, initializer);
                 }
             }
         }
@@ -53204,9 +53248,9 @@ var ts;
                 if (ts.isIdentifier(original) && original.parent) {
                     var declaration = resolver.getReferencedValueDeclaration(original);
                     if (declaration) {
-                        var name_36 = ts.getProperty(renamedCatchVariableDeclarations, String(ts.getOriginalNodeId(declaration)));
-                        if (name_36) {
-                            var clone_6 = ts.getMutableClone(name_36);
+                        var name_37 = ts.getProperty(renamedCatchVariableDeclarations, String(ts.getOriginalNodeId(declaration)));
+                        if (name_37) {
+                            var clone_6 = ts.getMutableClone(name_37);
                             ts.setSourceMapRange(clone_6, node);
                             ts.setCommentRange(clone_6, node);
                             return clone_6;
@@ -56755,8 +56799,8 @@ var ts;
                         /*location*/ node);
                     }
                     else if (ts.isImportSpecifier(importDeclaration)) {
-                        var name_37 = importDeclaration.propertyName || importDeclaration.name;
-                        return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent.parent.parent), ts.getSynthesizedClone(name_37), 
+                        var name_38 = importDeclaration.propertyName || importDeclaration.name;
+                        return ts.createPropertyAccess(ts.getGeneratedNameForNode(importDeclaration.parent.parent.parent), ts.getSynthesizedClone(name_38), 
                         /*location*/ node);
                     }
                 }
@@ -58297,9 +58341,9 @@ var ts;
             var count = 0;
             while (true) {
                 count++;
-                var name_38 = baseName + "_" + count;
-                if (!(name_38 in currentIdentifiers)) {
-                    return name_38;
+                var name_39 = baseName + "_" + count;
+                if (!(name_39 in currentIdentifiers)) {
+                    return name_39;
                 }
             }
         }
@@ -59247,6 +59291,11 @@ var ts;
                         return symbolAccessibilityResult.errorModuleName ?
                             ts.Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
                             ts.Diagnostics.Parameter_0_of_call_signature_from_exported_interface_has_or_is_using_private_name_1;
+                    case 155 /* IndexSignature */:
+                        // Interfaces cannot have parameter types that cannot be named
+                        return symbolAccessibilityResult.errorModuleName ?
+                            ts.Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2 :
+                            ts.Diagnostics.Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1;
                     case 149 /* MethodDeclaration */:
                     case 148 /* MethodSignature */:
                         if (ts.hasModifier(node.parent, 32 /* Static */)) {
@@ -61607,10 +61656,10 @@ var ts;
         */
         function makeTempVariableName(flags) {
             if (flags && !(tempFlags & flags)) {
-                var name_39 = flags === 268435456 /* _i */ ? "_i" : "_n";
-                if (isUniqueName(name_39)) {
+                var name_40 = flags === 268435456 /* _i */ ? "_i" : "_n";
+                if (isUniqueName(name_40)) {
                     tempFlags |= flags;
-                    return name_39;
+                    return name_40;
                 }
             }
             while (true) {
@@ -61618,11 +61667,11 @@ var ts;
                 tempFlags++;
                 // Skip over 'i' and 'n'
                 if (count !== 8 && count !== 13) {
-                    var name_40 = count < 26
+                    var name_41 = count < 26
                         ? "_" + String.fromCharCode(97 /* a */ + count)
                         : "_" + (count - 26);
-                    if (isUniqueName(name_40)) {
-                        return name_40;
+                    if (isUniqueName(name_41)) {
+                        return name_41;
                     }
                 }
             }
@@ -62073,10 +62122,10 @@ var ts;
         var resolutions = [];
         var cache = ts.createMap();
         for (var _i = 0, names_1 = names; _i < names_1.length; _i++) {
-            var name_41 = names_1[_i];
-            var result = name_41 in cache
-                ? cache[name_41]
-                : cache[name_41] = loader(name_41, containingFile);
+            var name_42 = names_1[_i];
+            var result = name_42 in cache
+                ? cache[name_42]
+                : cache[name_42] = loader(name_42, containingFile);
             resolutions.push(result);
         }
         return resolutions;
@@ -64125,11 +64174,11 @@ var ts;
         function serializeCompilerOptions(options) {
             var result = ts.createMap();
             var optionsNameMap = getOptionNameMap().optionNameMap;
-            for (var name_42 in options) {
-                if (ts.hasProperty(options, name_42)) {
+            for (var name_43 in options) {
+                if (ts.hasProperty(options, name_43)) {
                     // tsconfig only options cannot be specified via command line,
                     // so we can assume that only types that can appear here string | number | boolean
-                    switch (name_42) {
+                    switch (name_43) {
                         case "init":
                         case "watch":
                         case "version":
@@ -64137,14 +64186,14 @@ var ts;
                         case "project":
                             break;
                         default:
-                            var value = options[name_42];
-                            var optionDefinition = optionsNameMap[name_42.toLowerCase()];
+                            var value = options[name_43];
+                            var optionDefinition = optionsNameMap[name_43.toLowerCase()];
                             if (optionDefinition) {
                                 var customTypeMap = getCustomTypeMapOfCommandLineOption(optionDefinition);
                                 if (!customTypeMap) {
                                     // There is no map associated with this compiler option then use the value as-is
                                     // This is the case if the value is expect to be string, number, boolean or list of string
-                                    result[name_42] = value;
+                                    result[name_43] = value;
                                 }
                                 else {
                                     if (optionDefinition.type === "list") {
@@ -64153,11 +64202,11 @@ var ts;
                                             var element = _a[_i];
                                             convertedValue.push(getNameOfCompilerOptionValue(element, customTypeMap));
                                         }
-                                        result[name_42] = convertedValue;
+                                        result[name_43] = convertedValue;
                                     }
                                     else {
                                         // There is a typeMap associated with this command-line option so use it to map value back to its name
-                                        result[name_42] = getNameOfCompilerOptionValue(value, customTypeMap);
+                                        result[name_43] = getNameOfCompilerOptionValue(value, customTypeMap);
                                     }
                                 }
                             }
@@ -67190,14 +67239,14 @@ var ts;
             function getJavaScriptCompletionEntries(sourceFile, position, uniqueNames) {
                 var entries = [];
                 var nameTable = ts.getNameTable(sourceFile);
-                for (var name_43 in nameTable) {
+                for (var name_44 in nameTable) {
                     // Skip identifiers produced only from the current location
-                    if (nameTable[name_43] === position) {
+                    if (nameTable[name_44] === position) {
                         continue;
                     }
-                    if (!uniqueNames[name_43]) {
-                        uniqueNames[name_43] = name_43;
-                        var displayName = getCompletionEntryDisplayName(ts.unescapeIdentifier(name_43), compilerOptions.target, /*performCharacterChecks*/ true);
+                    if (!uniqueNames[name_44]) {
+                        uniqueNames[name_44] = name_44;
+                        var displayName = getCompletionEntryDisplayName(ts.unescapeIdentifier(name_44), compilerOptions.target, /*performCharacterChecks*/ true);
                         if (displayName) {
                             var entry = {
                                 name: displayName,
@@ -68502,8 +68551,8 @@ var ts;
                     if (element.getStart() <= position && position <= element.getEnd()) {
                         continue;
                     }
-                    var name_44 = element.propertyName || element.name;
-                    existingImportsOrExports[name_44.text] = true;
+                    var name_45 = element.propertyName || element.name;
+                    existingImportsOrExports[name_45.text] = true;
                 }
                 if (!ts.someProperties(existingImportsOrExports)) {
                     return ts.filter(exportsOfModule, function (e) { return e.name !== "default"; });
@@ -71120,9 +71169,9 @@ var ts;
                 }
             }
             // Add the cached typing locations for inferred typings that are already installed
-            for (var name_45 in packageNameToTypingLocation) {
-                if (name_45 in inferredTypings && !inferredTypings[name_45]) {
-                    inferredTypings[name_45] = packageNameToTypingLocation[name_45];
+            for (var name_46 in packageNameToTypingLocation) {
+                if (name_46 in inferredTypings && !inferredTypings[name_46]) {
+                    inferredTypings[name_46] = packageNameToTypingLocation[name_46];
                 }
             }
             // Remove typings that the user has added to the exclude list
@@ -71260,12 +71309,12 @@ var ts;
                     return;
                 }
                 var nameToDeclarations = sourceFile.getNamedDeclarations();
-                for (var name_46 in nameToDeclarations) {
-                    var declarations = nameToDeclarations[name_46];
+                for (var name_47 in nameToDeclarations) {
+                    var declarations = nameToDeclarations[name_47];
                     if (declarations) {
                         // First do a quick check to see if the name of the declaration matches the
                         // last portion of the (possibly) dotted name they're searching for.
-                        var matches = patternMatcher.getMatchesForLastSegmentOfPattern(name_46);
+                        var matches = patternMatcher.getMatchesForLastSegmentOfPattern(name_47);
                         if (!matches) {
                             continue;
                         }
@@ -71278,14 +71327,14 @@ var ts;
                                 if (!containers) {
                                     return undefined;
                                 }
-                                matches = patternMatcher.getMatches(containers, name_46);
+                                matches = patternMatcher.getMatches(containers, name_47);
                                 if (!matches) {
                                     continue;
                                 }
                             }
                             var fileName = sourceFile.fileName;
                             var matchKind = bestMatchKind(matches);
-                            rawItems.push({ name: name_46, fileName: fileName, matchKind: matchKind, isCaseSensitive: allMatchesAreCaseSensitive(matches), declaration: declaration });
+                            rawItems.push({ name: name_47, fileName: fileName, matchKind: matchKind, isCaseSensitive: allMatchesAreCaseSensitive(matches), declaration: declaration });
                         }
                     }
                 }
@@ -71574,9 +71623,9 @@ var ts;
                 case 174 /* BindingElement */:
                 case 223 /* VariableDeclaration */:
                     var decl = node;
-                    var name_47 = decl.name;
-                    if (ts.isBindingPattern(name_47)) {
-                        addChildrenRecursively(name_47);
+                    var name_48 = decl.name;
+                    if (ts.isBindingPattern(name_48)) {
+                        addChildrenRecursively(name_48);
                     }
                     else if (decl.initializer && isFunctionOrClassExpression(decl.initializer)) {
                         // For `const x = function() {}`, just use the function node, not the const.
@@ -75075,9 +75124,9 @@ var ts;
             }
             Rules.prototype.getRuleName = function (rule) {
                 var o = this;
-                for (var name_48 in o) {
-                    if (o[name_48] === rule) {
-                        return name_48;
+                for (var name_49 in o) {
+                    if (o[name_49] === rule) {
+                        return name_49;
                     }
                 }
                 throw new Error("Unknown rule");
diff --git a/lib/typingsInstaller.js b/lib/typingsInstaller.js
index 1d9e78f7228..25933d96042 100644
--- a/lib/typingsInstaller.js
+++ b/lib/typingsInstaller.js
@@ -137,7 +137,7 @@ var ts;
 })(ts || (ts = {}));
 var ts;
 (function (ts) {
-    ts.version = "2.1.3";
+    ts.version = "2.1.4";
 })(ts || (ts = {}));
 (function (ts) {
     var createObject = Object.create;
@@ -2673,6 +2673,7 @@ var ts;
         Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword: { code: 2340, category: ts.DiagnosticCategory.Error, key: "Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword_2340", message: "Only public and protected methods of the base class are accessible via the 'super' keyword." },
         Property_0_is_private_and_only_accessible_within_class_1: { code: 2341, category: ts.DiagnosticCategory.Error, key: "Property_0_is_private_and_only_accessible_within_class_1_2341", message: "Property '{0}' is private and only accessible within class '{1}'." },
         An_index_expression_argument_must_be_of_type_string_number_symbol_or_any: { code: 2342, category: ts.DiagnosticCategory.Error, key: "An_index_expression_argument_must_be_of_type_string_number_symbol_or_any_2342", message: "An index expression argument must be of type 'string', 'number', 'symbol', or 'any'." },
+        This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1: { code: 2343, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_named_1_but_module_0_has_no_exported_member_1_2343", message: "This syntax requires an imported helper named '{1}', but module '{0}' has no exported member '{1}'." },
         Type_0_does_not_satisfy_the_constraint_1: { code: 2344, category: ts.DiagnosticCategory.Error, key: "Type_0_does_not_satisfy_the_constraint_1_2344", message: "Type '{0}' does not satisfy the constraint '{1}'." },
         Argument_of_type_0_is_not_assignable_to_parameter_of_type_1: { code: 2345, category: ts.DiagnosticCategory.Error, key: "Argument_of_type_0_is_not_assignable_to_parameter_of_type_1_2345", message: "Argument of type '{0}' is not assignable to parameter of type '{1}'." },
         Supplied_parameters_do_not_match_any_signature_of_call_target: { code: 2346, category: ts.DiagnosticCategory.Error, key: "Supplied_parameters_do_not_match_any_signature_of_call_target_2346", message: "Supplied parameters do not match any signature of call target." },
@@ -2683,6 +2684,7 @@ var ts;
         Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature: { code: 2351, category: ts.DiagnosticCategory.Error, key: "Cannot_use_new_with_an_expression_whose_type_lacks_a_call_or_construct_signature_2351", message: "Cannot use 'new' with an expression whose type lacks a call or construct signature." },
         Type_0_cannot_be_converted_to_type_1: { code: 2352, category: ts.DiagnosticCategory.Error, key: "Type_0_cannot_be_converted_to_type_1_2352", message: "Type '{0}' cannot be converted to type '{1}'." },
         Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1: { code: 2353, category: ts.DiagnosticCategory.Error, key: "Object_literal_may_only_specify_known_properties_and_0_does_not_exist_in_type_1_2353", message: "Object literal may only specify known properties, and '{0}' does not exist in type '{1}'." },
+        This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found: { code: 2354, category: ts.DiagnosticCategory.Error, key: "This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found_2354", message: "This syntax requires an imported helper but module '{0}' cannot be found." },
         A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value: { code: 2355, category: ts.DiagnosticCategory.Error, key: "A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value_2355", message: "A function whose declared type is neither 'void' nor 'any' must return a value." },
         An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type: { code: 2356, category: ts.DiagnosticCategory.Error, key: "An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type_2356", message: "An arithmetic operand must be of type 'any', 'number' or an enum type." },
         The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access: { code: 2357, category: ts.DiagnosticCategory.Error, key: "The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access_2357", message: "The operand of an increment or decrement operator must be a variable or a property access." },
@@ -2989,6 +2991,8 @@ var ts;
         Default_export_of_the_module_has_or_is_using_private_name_0: { code: 4082, category: ts.DiagnosticCategory.Error, key: "Default_export_of_the_module_has_or_is_using_private_name_0_4082", message: "Default export of the module has or is using private name '{0}'." },
         Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1: { code: 4083, category: ts.DiagnosticCategory.Error, key: "Type_parameter_0_of_exported_type_alias_has_or_is_using_private_name_1_4083", message: "Type parameter '{0}' of exported type alias has or is using private name '{1}'." },
         Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_library_to_resolve_the_conflict: { code: 4090, category: ts.DiagnosticCategory.Message, key: "Conflicting_definitions_for_0_found_at_1_and_2_Consider_installing_a_specific_version_of_this_librar_4090", message: "Conflicting definitions for '{0}' found at '{1}' and '{2}'. Consider installing a specific version of this library to resolve the conflict." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2: { code: 4091, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_name_1_from_private_module_2_4091", message: "Parameter '{0}' of index signature from exported interface has or is using name '{1}' from private module '{2}'." },
+        Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1: { code: 4092, category: ts.DiagnosticCategory.Error, key: "Parameter_0_of_index_signature_from_exported_interface_has_or_is_using_private_name_1_4092", message: "Parameter '{0}' of index signature from exported interface has or is using private name '{1}'." },
         The_current_host_does_not_support_the_0_option: { code: 5001, category: ts.DiagnosticCategory.Error, key: "The_current_host_does_not_support_the_0_option_5001", message: "The current host does not support the '{0}' option." },
         Cannot_find_the_common_subdirectory_path_for_the_input_files: { code: 5009, category: ts.DiagnosticCategory.Error, key: "Cannot_find_the_common_subdirectory_path_for_the_input_files_5009", message: "Cannot find the common subdirectory path for the input files." },
         File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0: { code: 5010, category: ts.DiagnosticCategory.Error, key: "File_specification_cannot_end_in_a_recursive_directory_wildcard_Asterisk_Asterisk_Colon_0_5010", message: "File specification cannot end in a recursive directory wildcard ('**'): '{0}'." },