Merge pull request #1978 from Microsoft/esSymbols

Support ES6 built-in symbols

src/compiler/binder.ts

@@ -51,17 +51,6 @@ module ts {
         }
     }
 
-    /**
-     * A declaration has a dynamic name if both of the following are true:
-     *   1. The declaration has a computed property name
-     *   2. The computed name is *not* expressed as Symbol.<name>, where name
-     *      is a property of the Symbol constructor that denotes a built in
-     *      Symbol.
-     */
-    export function hasDynamicName(declaration: Declaration): boolean {
-        return declaration.name && declaration.name.kind === SyntaxKind.ComputedPropertyName;
-    }
-
     export function bindSourceFile(file: SourceFile): void {
         var start = new Date().getTime();
         bindSourceFileWorker(file);
@@ -98,13 +87,18 @@ module ts {
             if (symbolKind & SymbolFlags.Value && !symbol.valueDeclaration) symbol.valueDeclaration = node;
         }
 
-        // Should not be called on a declaration with a computed property name.
+        // Should not be called on a declaration with a computed property name,
+        // unless it is a well known Symbol.
         function getDeclarationName(node: Declaration): string {
             if (node.name) {
                 if (node.kind === SyntaxKind.ModuleDeclaration && node.name.kind === SyntaxKind.StringLiteral) {
                     return '"' + (<LiteralExpression>node.name).text + '"';
                 }
-                Debug.assert(!hasDynamicName(node));
+                if (node.name.kind === SyntaxKind.ComputedPropertyName) {
+                    var nameExpression = (<ComputedPropertyName>node.name).expression;
+                    Debug.assert(isWellKnownSymbolSyntactically(nameExpression));
+                    return getPropertyNameForKnownSymbolName((<PropertyAccessExpression>nameExpression).name.text);
+                }
                 return (<Identifier | LiteralExpression>node.name).text;
             }
             switch (node.kind) {

src/compiler/checker.ts

@@ -67,6 +67,7 @@ module ts {
         var stringType = createIntrinsicType(TypeFlags.String, "string");
         var numberType = createIntrinsicType(TypeFlags.Number, "number");
         var booleanType = createIntrinsicType(TypeFlags.Boolean, "boolean");
+        var esSymbolType = createIntrinsicType(TypeFlags.ESSymbol, "symbol");
         var voidType = createIntrinsicType(TypeFlags.Void, "void");
         var undefinedType = createIntrinsicType(TypeFlags.Undefined | TypeFlags.ContainsUndefinedOrNull, "undefined");
         var nullType = createIntrinsicType(TypeFlags.Null | TypeFlags.ContainsUndefinedOrNull, "null");
@@ -84,6 +85,7 @@ module ts {
         var globals: SymbolTable = {};
 
         var globalArraySymbol: Symbol;
+        var globalESSymbolConstructorSymbol: Symbol;
 
         var globalObjectType: ObjectType;
         var globalFunctionType: ObjectType;
@@ -93,6 +95,7 @@ module ts {
         var globalBooleanType: ObjectType;
         var globalRegExpType: ObjectType;
         var globalTemplateStringsArrayType: ObjectType;
+        var globalESSymbolType: ObjectType;
 
         var anyArrayType: Type;
 
@@ -120,6 +123,10 @@ module ts {
             "boolean": {
                 type: booleanType,
                 flags: TypeFlags.Boolean
+            },
+            "symbol": {
+                type: esSymbolType,
+                flags: TypeFlags.ESSymbol
             }
         };
 
@@ -706,9 +713,15 @@ module ts {
             return type;
         }
 
-        // A reserved member name starts with two underscores followed by a non-underscore
+        // A reserved member name starts with two underscores, but the third character cannot be an underscore
+        // or the @ symbol. A third underscore indicates an escaped form of an identifer that started
+        // with at least two underscores. The @ character indicates that the name is denoted by a well known ES
+        // Symbol instance.
         function isReservedMemberName(name: string) {
-            return name.charCodeAt(0) === CharacterCodes._ && name.charCodeAt(1) === CharacterCodes._ && name.charCodeAt(2) !== CharacterCodes._;
+            return name.charCodeAt(0) === CharacterCodes._ &&
+                name.charCodeAt(1) === CharacterCodes._ &&
+                name.charCodeAt(2) !== CharacterCodes._ &&
+                name.charCodeAt(2) !== CharacterCodes.at;
         }
 
         function getNamedMembers(members: SymbolTable): Symbol[] {
@@ -2489,9 +2502,9 @@ module ts {
             return getPropertiesOfObjectType(getApparentType(type));
         }
 
-        // For a type parameter, return the base constraint of the type parameter. For the string, number, and
-        // boolean primitive types, return the corresponding object types.Otherwise return the type itself.
-        // Note that the apparent type of a union type is the union type itself.
+        // For a type parameter, return the base constraint of the type parameter. For the string, number,
+        // boolean, and symbol primitive types, return the corresponding object types. Otherwise return the
+        // type itself. Note that the apparent type of a union type is the union type itself.
         function getApparentType(type: Type): Type {
             if (type.flags & TypeFlags.TypeParameter) {
                 do {
@@ -2510,6 +2523,9 @@ module ts {
             else if (type.flags & TypeFlags.Boolean) {
                 type = globalBooleanType;
             }
+            else if (type.flags & TypeFlags.ESSymbol) {
+                type = globalESSymbolType;
+            }
             return type;
         }
 
@@ -2999,12 +3015,24 @@ module ts {
             return <ObjectType>type;
         }
 
-        function getGlobalSymbol(name: string): Symbol {
-            return resolveName(undefined, name, SymbolFlags.Type, Diagnostics.Cannot_find_global_type_0, name);
+        function getGlobalValueSymbol(name: string): Symbol {
+            return getGlobalSymbol(name, SymbolFlags.Value, Diagnostics.Cannot_find_global_value_0);
+        }
+
+        function getGlobalTypeSymbol(name: string): Symbol {
+            return getGlobalSymbol(name, SymbolFlags.Type, Diagnostics.Cannot_find_global_type_0);
+        }
+
+        function getGlobalSymbol(name: string, meaning: SymbolFlags, diagnostic: DiagnosticMessage): Symbol {
+            return resolveName(undefined, name, meaning, diagnostic, name);
         }
 
         function getGlobalType(name: string): ObjectType {
-            return getTypeOfGlobalSymbol(getGlobalSymbol(name), 0);
+            return getTypeOfGlobalSymbol(getGlobalTypeSymbol(name), 0);
+        }
+
+        function getGlobalESSymbolConstructorSymbol() {
+            return globalESSymbolConstructorSymbol || (globalESSymbolConstructorSymbol = getGlobalValueSymbol("Symbol"));
         }
 
         function createArrayType(elementType: Type): Type {
@@ -3174,6 +3202,8 @@ module ts {
                     return numberType;
                 case SyntaxKind.BooleanKeyword:
                     return booleanType;
+                case SyntaxKind.SymbolKeyword:
+                    return esSymbolType;
                 case SyntaxKind.VoidKeyword:
                     return voidType;
                 case SyntaxKind.StringLiteral:
@@ -4740,7 +4770,7 @@ module ts {
                 if (assumeTrue) {
                     // Assumed result is true. If check was not for a primitive type, remove all primitive types
                     if (!typeInfo) {
-                        return removeTypesFromUnionType(type, /*typeKind*/ TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.Boolean, /*isOfTypeKind*/ true);
+                        return removeTypesFromUnionType(type, /*typeKind*/ TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.Boolean | TypeFlags.ESSymbol, /*isOfTypeKind*/ true);
                     }
                     // Check was for a primitive type, return that primitive type if it is a subtype
                     if (isTypeSubtypeOf(typeInfo.type, type)) {
@@ -5475,7 +5505,7 @@ module ts {
         function isNumericComputedName(name: ComputedPropertyName): boolean {
             // It seems odd to consider an expression of type Any to result in a numeric name,
             // but this behavior is consistent with checkIndexedAccess
-            return isTypeOfKind(checkComputedPropertyName(name), TypeFlags.Any | TypeFlags.NumberLike);
+            return allConstituentTypesHaveKind(checkComputedPropertyName(name), TypeFlags.Any | TypeFlags.NumberLike);
         }
 
         function isNumericLiteralName(name: string) {
@@ -5508,10 +5538,13 @@ module ts {
             if (!links.resolvedType) {
                 links.resolvedType = checkExpression(node.expression);
 
-                // This will allow types number, string, or any. It will also allow enums, the unknown
+                // This will allow types number, string, symbol or any. It will also allow enums, the unknown
                 // type, and any union of these types (like string | number).
-                if (!isTypeOfKind(links.resolvedType, TypeFlags.Any | TypeFlags.NumberLike | TypeFlags.StringLike)) {
-                    error(node, Diagnostics.A_computed_property_name_must_be_of_type_string_number_or_any);
+                if (!allConstituentTypesHaveKind(links.resolvedType, TypeFlags.Any | TypeFlags.NumberLike | TypeFlags.StringLike | TypeFlags.ESSymbol)) {
+                    error(node, Diagnostics.A_computed_property_name_must_be_of_type_string_number_symbol_or_any);
+                }
+                else {
+                    checkThatExpressionIsProperSymbolReference(node.expression, links.resolvedType, /*reportError*/ true);
                 }
             }
 
@@ -5760,8 +5793,8 @@ module ts {
 
             // See if we can index as a property.
             if (node.argumentExpression) {
-                if (node.argumentExpression.kind === SyntaxKind.StringLiteral || node.argumentExpression.kind === SyntaxKind.NumericLiteral) {
-                    var name = (<LiteralExpression>node.argumentExpression).text;
+                var name = getPropertyNameForIndexedAccess(node.argumentExpression, indexType);
+                if (name !== undefined) {
                     var prop = getPropertyOfType(objectType, name);
                     if (prop) {
                         getNodeLinks(node).resolvedSymbol = prop;
@@ -5775,10 +5808,10 @@ module ts {
             }
 
             // Check for compatible indexer types.
-            if (isTypeOfKind(indexType, TypeFlags.Any | TypeFlags.StringLike | TypeFlags.NumberLike)) {
+            if (allConstituentTypesHaveKind(indexType, TypeFlags.Any | TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.ESSymbol)) {
 
                 // Try to use a number indexer.
-                if (isTypeOfKind(indexType, TypeFlags.Any | TypeFlags.NumberLike)) {
+                if (allConstituentTypesHaveKind(indexType, TypeFlags.Any | TypeFlags.NumberLike)) {
                     var numberIndexType = getIndexTypeOfType(objectType, IndexKind.Number);
                     if (numberIndexType) {
                         return numberIndexType;
@@ -5800,11 +5833,78 @@ module ts {
             }
 
             // REVIEW: Users should know the type that was actually used.
-            error(node, Diagnostics.An_index_expression_argument_must_be_of_type_string_number_or_any);
+            error(node, Diagnostics.An_index_expression_argument_must_be_of_type_string_number_symbol_or_any);
 
             return unknownType;
         }
 
+        /**
+         * If indexArgumentExpression is a string literal or number literal, returns its text.
+         * If indexArgumentExpression is a well known symbol, returns the property name corresponding
+         *    to this symbol, as long as it is a proper symbol reference.
+         * Otherwise, returns undefined.
+         */
+        function getPropertyNameForIndexedAccess(indexArgumentExpression: Expression, indexArgumentType: Type): string {
+            if (indexArgumentExpression.kind === SyntaxKind.StringLiteral || indexArgumentExpression.kind === SyntaxKind.NumericLiteral) {
+                return (<LiteralExpression>indexArgumentExpression).text;
+            }
+            if (checkThatExpressionIsProperSymbolReference(indexArgumentExpression, indexArgumentType, /*reportError*/ false)) {
+                var rightHandSideName = (<Identifier>(<PropertyAccessExpression>indexArgumentExpression).name).text;
+                return getPropertyNameForKnownSymbolName(rightHandSideName);
+            }
+
+            return undefined;
+        }
+
+        /**
+         * A proper symbol reference requires the following:
+         *   1. The property access denotes a property that exists
+         *   2. The expression is of the form Symbol.<identifier>
+         *   3. The property access is of the primitive type symbol.
+         *   4. Symbol in this context resolves to the global Symbol object
+         */
+        function checkThatExpressionIsProperSymbolReference(expression: Expression, expressionType: Type, reportError: boolean): boolean {
+            if (expressionType === unknownType) {
+                // There is already an error, so no need to report one.
+                return false;
+            }
+
+            if (!isWellKnownSymbolSyntactically(expression)) {
+                return false;
+            }
+
+            // Make sure the property type is the primitive symbol type
+            if ((expressionType.flags & TypeFlags.ESSymbol) === 0) {
+                if (reportError) {
+                    error(expression, Diagnostics.A_computed_property_name_of_the_form_0_must_be_of_type_symbol, getTextOfNode(expression));
+                }
+                return false;
+            }
+
+            // The name is Symbol.<someName>, so make sure Symbol actually resolves to the
+            // global Symbol object
+            var leftHandSide = <Identifier>(<PropertyAccessExpression>expression).expression;
+            var leftHandSideSymbol = getResolvedSymbol(leftHandSide);
+            if (!leftHandSideSymbol) {
+                return false;
+            }
+            
+            var globalESSymbol = getGlobalESSymbolConstructorSymbol();
+            if (!globalESSymbol) {
+                // Already errored when we tried to look up the symbol
+                return false;
+            }
+
+            if (leftHandSideSymbol !== globalESSymbol) {
+                if (reportError) {
+                    error(leftHandSide, Diagnostics.Symbol_reference_does_not_refer_to_the_global_Symbol_constructor_object);
+                }
+                return false;
+            }
+
+            return true;
+        }
+
         function resolveUntypedCall(node: CallLikeExpression): Signature {
             if (node.kind === SyntaxKind.TaggedTemplateExpression) {
                 checkExpression((<TaggedTemplateExpression>node).template);
@@ -6719,7 +6819,7 @@ module ts {
         }
 
         function checkArithmeticOperandType(operand: Node, type: Type, diagnostic: DiagnosticMessage): boolean {
-            if (!isTypeOfKind(type, TypeFlags.Any | TypeFlags.NumberLike)) {
+            if (!allConstituentTypesHaveKind(type, TypeFlags.Any | TypeFlags.NumberLike)) {
                 error(operand, diagnostic);
                 return false;
             }
@@ -6835,6 +6935,9 @@ module ts {
                 case SyntaxKind.PlusToken:
                 case SyntaxKind.MinusToken:
                 case SyntaxKind.TildeToken:
+                    if (someConstituentTypeHasKind(operandType, TypeFlags.ESSymbol)) {
+                        error(node.operand, Diagnostics.The_0_operator_cannot_be_applied_to_type_symbol, tokenToString(node.operator));
+                    }
                     return numberType;
                 case SyntaxKind.ExclamationToken:
                     return booleanType;
@@ -6870,8 +6973,26 @@ module ts {
             return numberType;
         }
 
-        // Return true if type has the given flags, or is a union type composed of types that all have those flags
-        function isTypeOfKind(type: Type, kind: TypeFlags): boolean {
+        // Just like isTypeOfKind below, except that it returns true if *any* constituent
+        // has this kind.
+        function someConstituentTypeHasKind(type: Type, kind: TypeFlags): boolean {
+            if (type.flags & kind) {
+                return true;
+            }
+            if (type.flags & TypeFlags.Union) {
+                var types = (<UnionType>type).types;
+                for (var i = 0; i < types.length; i++) {
+                    if (types[i].flags & kind) {
+                        return true;
+                    }
+                }
+                return false;
+            }
+            return false;
+        }
+
+        // Return true if type has the given flags, or is a union type composed of types that all have those flags.
+        function allConstituentTypesHaveKind(type: Type, kind: TypeFlags): boolean {
             if (type.flags & kind) {
                 return true;
             }
@@ -6901,7 +7022,7 @@ module ts {
             // and the right operand to be of type Any or a subtype of the 'Function' interface type. 
             // The result is always of the Boolean primitive type.
             // NOTE: do not raise error if leftType is unknown as related error was already reported
-            if (isTypeOfKind(leftType, TypeFlags.Primitive)) {
+            if (allConstituentTypesHaveKind(leftType, TypeFlags.Primitive)) {
                 error(node.left, Diagnostics.The_left_hand_side_of_an_instanceof_expression_must_be_of_type_any_an_object_type_or_a_type_parameter);
             }
             // NOTE: do not raise error if right is unknown as related error was already reported
@@ -6916,10 +7037,10 @@ module ts {
             // The in operator requires the left operand to be of type Any, the String primitive type, or the Number primitive type,
             // and the right operand to be of type Any, an object type, or a type parameter type.
             // The result is always of the Boolean primitive type.
-            if (!isTypeOfKind(leftType, TypeFlags.Any | TypeFlags.StringLike | TypeFlags.NumberLike)) {
-                error(node.left, Diagnostics.The_left_hand_side_of_an_in_expression_must_be_of_types_any_string_or_number);
+            if (!allConstituentTypesHaveKind(leftType, TypeFlags.Any | TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.ESSymbol)) {
+                error(node.left, Diagnostics.The_left_hand_side_of_an_in_expression_must_be_of_type_any_string_number_or_symbol);
             }
-            if (!isTypeOfKind(rightType, TypeFlags.Any | TypeFlags.ObjectType | TypeFlags.TypeParameter)) {
+            if (!allConstituentTypesHaveKind(rightType, TypeFlags.Any | TypeFlags.ObjectType | TypeFlags.TypeParameter)) {
                 error(node.right, Diagnostics.The_right_hand_side_of_an_in_expression_must_be_of_type_any_an_object_type_or_a_type_parameter);
             }
             return booleanType;
@@ -7080,19 +7201,26 @@ module ts {
                     if (rightType.flags & (TypeFlags.Undefined | TypeFlags.Null)) rightType = leftType;
 
                     var resultType: Type;
-                    if (isTypeOfKind(leftType, TypeFlags.NumberLike) && isTypeOfKind(rightType, TypeFlags.NumberLike)) {
+                    if (allConstituentTypesHaveKind(leftType, TypeFlags.NumberLike) && allConstituentTypesHaveKind(rightType, TypeFlags.NumberLike)) {
                         // Operands of an enum type are treated as having the primitive type Number.
                         // If both operands are of the Number primitive type, the result is of the Number primitive type.
                         resultType = numberType;
                     }
-                    else if (isTypeOfKind(leftType, TypeFlags.StringLike) || isTypeOfKind(rightType, TypeFlags.StringLike)) {
-                        // If one or both operands are of the String primitive type, the result is of the String primitive type.
-                        resultType = stringType;
-                    }
-                    else if (leftType.flags & TypeFlags.Any || rightType.flags & TypeFlags.Any) {
-                        // Otherwise, the result is of type Any.
-                        // NOTE: unknown type here denotes error type. Old compiler treated this case as any type so do we.
-                        resultType = anyType;
+                    else {
+                        if (allConstituentTypesHaveKind(leftType, TypeFlags.StringLike) || allConstituentTypesHaveKind(rightType, TypeFlags.StringLike)) {
+                            // If one or both operands are of the String primitive type, the result is of the String primitive type.
+                            resultType = stringType;
+                        }
+                        else if (leftType.flags & TypeFlags.Any || rightType.flags & TypeFlags.Any) {
+                            // Otherwise, the result is of type Any.
+                            // NOTE: unknown type here denotes error type. Old compiler treated this case as any type so do we.
+                            resultType = anyType;
+                        }
+
+                        // Symbols are not allowed at all in arithmetic expressions
+                        if (resultType && !checkForDisallowedESSymbolOperand(operator)) {
+                            return resultType;
+                        }
                     }
 
                     if (!resultType) {
@@ -7104,14 +7232,18 @@ module ts {
                         checkAssignmentOperator(resultType);
                     }
                     return resultType;
-                case SyntaxKind.EqualsEqualsToken:
-                case SyntaxKind.ExclamationEqualsToken:
-                case SyntaxKind.EqualsEqualsEqualsToken:
-                case SyntaxKind.ExclamationEqualsEqualsToken:
                 case SyntaxKind.LessThanToken:
                 case SyntaxKind.GreaterThanToken:
                 case SyntaxKind.LessThanEqualsToken:
                 case SyntaxKind.GreaterThanEqualsToken:
+                    if (!checkForDisallowedESSymbolOperand(operator)) {
+                        return booleanType;
+                    }
+                    // Fall through
+                case SyntaxKind.EqualsEqualsToken:
+                case SyntaxKind.ExclamationEqualsToken:
+                case SyntaxKind.EqualsEqualsEqualsToken:
+                case SyntaxKind.ExclamationEqualsEqualsToken:
                     if (!isTypeAssignableTo(leftType, rightType) && !isTypeAssignableTo(rightType, leftType)) {
                         reportOperatorError();
                     }
@@ -7131,6 +7263,20 @@ module ts {
                     return rightType;
             }
 
+            // Return type is true if there was no error, false if there was an error.
+            function checkForDisallowedESSymbolOperand(operator: SyntaxKind): boolean {
+                var offendingSymbolOperand =
+                    someConstituentTypeHasKind(leftType, TypeFlags.ESSymbol) ? node.left :
+                    someConstituentTypeHasKind(rightType, TypeFlags.ESSymbol) ? node.right :
+                    undefined;
+                if (offendingSymbolOperand) {
+                    error(offendingSymbolOperand, Diagnostics.The_0_operator_cannot_be_applied_to_type_symbol, tokenToString(operator));
+                    return false;
+                }
+
+                return true;
+            }
+
             function getSuggestedBooleanOperator(operator: SyntaxKind): SyntaxKind {
                 switch (operator) {
                     case SyntaxKind.BarToken:
@@ -7216,7 +7362,10 @@ module ts {
         }
 
         function checkPropertyAssignment(node: PropertyAssignment, contextualMapper?: TypeMapper): Type {
-            if (hasDynamicName(node)) {
+            // Do not use hasDynamicName here, because that returns false for well known symbols.
+            // We want to perform checkComputedPropertyName for all computed properties, including
+            // well known symbols.
+            if (node.name.kind === SyntaxKind.ComputedPropertyName) {
                 checkComputedPropertyName(<ComputedPropertyName>node.name);
             }
 
@@ -7227,7 +7376,10 @@ module ts {
             // Grammar checking
             checkGrammarMethod(node);
 
-            if (hasDynamicName(node)) {
+            // Do not use hasDynamicName here, because that returns false for well known symbols.
+            // We want to perform checkComputedPropertyName for all computed properties, including
+            // well known symbols.
+            if (node.name.kind === SyntaxKind.ComputedPropertyName) {
                 checkComputedPropertyName(<ComputedPropertyName>node.name);
             }
 
@@ -7490,7 +7642,7 @@ module ts {
 
         function checkPropertyDeclaration(node: PropertyDeclaration) {
             // Grammar checking
-            checkGrammarModifiers(node) || checkGrammarProperty(node);
+            checkGrammarModifiers(node) || checkGrammarProperty(node) || checkGrammarComputedPropertyName(node.name);
 
             checkVariableLikeDeclaration(node);
         }
@@ -8039,12 +8191,16 @@ module ts {
         function checkFunctionLikeDeclaration(node: FunctionLikeDeclaration): void {
             checkSignatureDeclaration(node);
 
-            if (hasDynamicName(node)) {
+            // Do not use hasDynamicName here, because that returns false for well known symbols.
+            // We want to perform checkComputedPropertyName for all computed properties, including
+            // well known symbols.
+            if (node.name.kind === SyntaxKind.ComputedPropertyName) {
                 // This check will account for methods in class/interface declarations,
                 // as well as accessors in classes/object literals
                 checkComputedPropertyName(<ComputedPropertyName>node.name);
             }
-            else {
+
+            if (!hasDynamicName(node)) {
                 // first we want to check the local symbol that contain this declaration
                 // - if node.localSymbol !== undefined - this is current declaration is exported and localSymbol points to the local symbol
                 // - if node.localSymbol === undefined - this node is non-exported so we can just pick the result of getSymbolOfNode
@@ -8302,12 +8458,14 @@ module ts {
         function checkVariableLikeDeclaration(node: VariableLikeDeclaration) {
             checkSourceElement(node.type);
             // For a computed property, just check the initializer and exit
-            if (hasDynamicName(node)) {
+            // Do not use hasDynamicName here, because that returns false for well known symbols.
+            // We want to perform checkComputedPropertyName for all computed properties, including
+            // well known symbols.
+            if (node.name.kind === SyntaxKind.ComputedPropertyName) {
                 checkComputedPropertyName(<ComputedPropertyName>node.name);
                 if (node.initializer) {
                     checkExpressionCached(node.initializer);
                 }
-                return;
             }
             // For a binding pattern, check contained binding elements
             if (isBindingPattern(node.name)) {
@@ -8482,7 +8640,7 @@ module ts {
                 //   and Expr must be an expression of type Any, an object type, or a type parameter type.
                 var varExpr = <Expression>node.initializer;
                 var exprType = checkExpression(varExpr);
-                if (exprType !== anyType && exprType !== stringType) {
+                if (!allConstituentTypesHaveKind(exprType, TypeFlags.Any | TypeFlags.StringLike)) {
                     error(varExpr, Diagnostics.The_left_hand_side_of_a_for_in_statement_must_be_of_type_string_or_any);
                 }
                 else {
@@ -8494,7 +8652,7 @@ module ts {
             var exprType = checkExpression(node.expression);
             // unknownType is returned i.e. if node.expression is identifier whose name cannot be resolved
             // in this case error about missing name is already reported - do not report extra one
-            if (!isTypeOfKind(exprType, TypeFlags.Any | TypeFlags.ObjectType | TypeFlags.TypeParameter)) {
+            if (!allConstituentTypesHaveKind(exprType, TypeFlags.Any | TypeFlags.ObjectType | TypeFlags.TypeParameter)) {
                 error(node.expression, Diagnostics.The_right_hand_side_of_a_for_in_statement_must_be_of_type_any_an_object_type_or_a_type_parameter);
             }
 
@@ -8745,6 +8903,7 @@ module ts {
                 case "number":
                 case "boolean":
                 case "string":
+                case "symbol":
                 case "void":
                     error(name, message, (<Identifier>name).text);
             }
@@ -8963,7 +9122,7 @@ module ts {
                             var typeName1 = typeToString(existing.containingType);
                             var typeName2 = typeToString(base);
 
-                            var errorInfo = chainDiagnosticMessages(undefined, Diagnostics.Named_properties_0_of_types_1_and_2_are_not_identical, prop.name, typeName1, typeName2);
+                            var errorInfo = chainDiagnosticMessages(undefined, Diagnostics.Named_property_0_of_types_1_and_2_are_not_identical, symbolToString(prop), typeName1, typeName2);
                             errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Interface_0_cannot_simultaneously_extend_types_1_and_2, typeToString(type), typeName1, typeName2);
                             diagnostics.add(createDiagnosticForNodeFromMessageChain(typeNode, errorInfo));
                         }
@@ -9755,6 +9914,7 @@ module ts {
                 case SyntaxKind.NumberKeyword:
                 case SyntaxKind.StringKeyword:
                 case SyntaxKind.BooleanKeyword:
+                case SyntaxKind.SymbolKeyword:
                     return true;
                 case SyntaxKind.VoidKeyword:
                     return node.parent.kind !== SyntaxKind.VoidExpression;
@@ -10279,7 +10439,7 @@ module ts {
             getSymbolLinks(unknownSymbol).type = unknownType;
             globals[undefinedSymbol.name] = undefinedSymbol;
             // Initialize special types
-            globalArraySymbol = getGlobalSymbol("Array");
+            globalArraySymbol = getGlobalTypeSymbol("Array");
             globalArrayType = getTypeOfGlobalSymbol(globalArraySymbol, 1);
             globalObjectType = getGlobalType("Object");
             globalFunctionType = getGlobalType("Function");
@@ -10287,11 +10447,24 @@ module ts {
             globalNumberType = getGlobalType("Number");
             globalBooleanType = getGlobalType("Boolean");
             globalRegExpType = getGlobalType("RegExp");
+
             // If we're in ES6 mode, load the TemplateStringsArray.
             // Otherwise, default to 'unknown' for the purposes of type checking in LS scenarios.
-            globalTemplateStringsArrayType = languageVersion >= ScriptTarget.ES6
-                ? getGlobalType("TemplateStringsArray")
-                : unknownType;
+            if (languageVersion >= ScriptTarget.ES6) {
+                globalTemplateStringsArrayType = getGlobalType("TemplateStringsArray");
+                globalESSymbolType = getGlobalType("Symbol");
+                globalESSymbolConstructorSymbol = getGlobalValueSymbol("Symbol");
+            }
+            else {
+                globalTemplateStringsArrayType = unknownType;
+
+                // Consider putting Symbol interface in lib.d.ts. On the plus side, putting it in lib.d.ts would make it
+                // extensible for Polyfilling Symbols. But putting it into lib.d.ts could also break users that have
+                // a global Symbol already, particularly if it is a class.
+                globalESSymbolType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
+                globalESSymbolConstructorSymbol = undefined;
+            }
+
             anyArrayType = createArrayType(anyType);
         }
 
@@ -10506,25 +10679,25 @@ module ts {
                     return grammarErrorOnNode(node, Diagnostics.An_index_signature_must_have_exactly_one_parameter);
                 }
             }
-            else if (parameter.dotDotDotToken) {
+            if (parameter.dotDotDotToken) {
                 return grammarErrorOnNode(parameter.dotDotDotToken, Diagnostics.An_index_signature_cannot_have_a_rest_parameter);
             }
-            else if (parameter.flags & NodeFlags.Modifier) {
+            if (parameter.flags & NodeFlags.Modifier) {
                 return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_cannot_have_an_accessibility_modifier);
             }
-            else if (parameter.questionToken) {
+            if (parameter.questionToken) {
                 return grammarErrorOnNode(parameter.questionToken, Diagnostics.An_index_signature_parameter_cannot_have_a_question_mark);
             }
-            else if (parameter.initializer) {
+            if (parameter.initializer) {
                 return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_cannot_have_an_initializer);
             }
-            else if (!parameter.type) {
+            if (!parameter.type) {
                 return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_must_have_a_type_annotation);
             }
-            else if (parameter.type.kind !== SyntaxKind.StringKeyword && parameter.type.kind !== SyntaxKind.NumberKeyword) {
+            if (parameter.type.kind !== SyntaxKind.StringKeyword && parameter.type.kind !== SyntaxKind.NumberKeyword) {
                 return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_type_must_be_string_or_number);
             }
-            else if (!node.type) {
+            if (!node.type) {
                 return grammarErrorOnNode(node, Diagnostics.An_index_signature_must_have_a_type_annotation);
             }
         }
@@ -10797,8 +10970,8 @@ module ts {
             }
         }
 
-        function checkGrammarForDisallowedComputedProperty(node: DeclarationName, message: DiagnosticMessage) {
-            if (node.kind === SyntaxKind.ComputedPropertyName) {
+        function checkGrammarForNonSymbolComputedProperty(node: DeclarationName, message: DiagnosticMessage) {
+            if (node.kind === SyntaxKind.ComputedPropertyName && !isWellKnownSymbolSyntactically((<ComputedPropertyName>node).expression)) {
                 return grammarErrorOnNode(node, message);
             }
         }
@@ -10829,17 +11002,17 @@ module ts {
                 // and accessors are not allowed in ambient contexts in general,
                 // so this error only really matters for methods.
                 if (isInAmbientContext(node)) {
-                    return checkGrammarForDisallowedComputedProperty(node.name, Diagnostics.Computed_property_names_are_not_allowed_in_an_ambient_context);
+                    return checkGrammarForNonSymbolComputedProperty(node.name, Diagnostics.A_computed_property_name_in_an_ambient_context_must_directly_refer_to_a_built_in_symbol);
                 }
                 else if (!node.body) {
-                    return checkGrammarForDisallowedComputedProperty(node.name, Diagnostics.Computed_property_names_are_not_allowed_in_method_overloads);
+                    return checkGrammarForNonSymbolComputedProperty(node.name, Diagnostics.A_computed_property_name_in_a_method_overload_must_directly_refer_to_a_built_in_symbol);
                 }
             }
             else if (node.parent.kind === SyntaxKind.InterfaceDeclaration) {
-                return checkGrammarForDisallowedComputedProperty(node.name, Diagnostics.Computed_property_names_are_not_allowed_in_interfaces);
+                return checkGrammarForNonSymbolComputedProperty(node.name, Diagnostics.A_computed_property_name_in_an_interface_must_directly_refer_to_a_built_in_symbol);
             }
             else if (node.parent.kind === SyntaxKind.TypeLiteral) {
-                return checkGrammarForDisallowedComputedProperty(node.name, Diagnostics.Computed_property_names_are_not_allowed_in_type_literals);
+                return checkGrammarForNonSymbolComputedProperty(node.name, Diagnostics.A_computed_property_name_in_a_type_literal_must_directly_refer_to_a_built_in_symbol);
             }
         }
 
@@ -11053,6 +11226,9 @@ module ts {
                 var inAmbientContext = isInAmbientContext(enumDecl);
                 for (var i = 0, n = enumDecl.members.length; i < n; i++) {
                     var node = enumDecl.members[i];
+                    // Do not use hasDynamicName here, because that returns false for well known symbols.
+                    // We want to perform checkComputedPropertyName for all computed properties, including
+                    // well known symbols.
                     if (node.name.kind === SyntaxKind.ComputedPropertyName) {
                         hasError = grammarErrorOnNode(node.name, Diagnostics.Computed_property_names_are_not_allowed_in_enums);
                     }
@@ -11133,17 +11309,17 @@ module ts {
         function checkGrammarProperty(node: PropertyDeclaration) {
             if (node.parent.kind === SyntaxKind.ClassDeclaration) {
                 if (checkGrammarForInvalidQuestionMark(node, node.questionToken, Diagnostics.A_class_member_cannot_be_declared_optional) ||
-                    checkGrammarForDisallowedComputedProperty(node.name, Diagnostics.Computed_property_names_are_not_allowed_in_class_property_declarations)) {
+                    checkGrammarForNonSymbolComputedProperty(node.name, Diagnostics.A_computed_property_name_in_a_class_property_declaration_must_directly_refer_to_a_built_in_symbol)) {
                     return true;
                 }
             }
             else if (node.parent.kind === SyntaxKind.InterfaceDeclaration) {
-                if (checkGrammarForDisallowedComputedProperty(node.name, Diagnostics.Computed_property_names_are_not_allowed_in_interfaces)) {
+                if (checkGrammarForNonSymbolComputedProperty(node.name, Diagnostics.A_computed_property_name_in_an_interface_must_directly_refer_to_a_built_in_symbol)) {
                     return true;
                 }
             }
             else if (node.parent.kind === SyntaxKind.TypeLiteral) {
-                if (checkGrammarForDisallowedComputedProperty(node.name, Diagnostics.Computed_property_names_are_not_allowed_in_type_literals)) {
+                if (checkGrammarForNonSymbolComputedProperty(node.name, Diagnostics.A_computed_property_name_in_a_type_literal_must_directly_refer_to_a_built_in_symbol)) {
                     return true;
                 }
             }

src/compiler/diagnosticInformationMap.generated.ts

@@ -123,12 +123,12 @@ module ts {
         An_object_member_cannot_be_declared_optional: { code: 1162, category: DiagnosticCategory.Error, key: "An object member cannot be declared optional." },
         yield_expression_must_be_contained_within_a_generator_declaration: { code: 1163, category: DiagnosticCategory.Error, key: "'yield' expression must be contained_within a generator declaration." },
         Computed_property_names_are_not_allowed_in_enums: { code: 1164, category: DiagnosticCategory.Error, key: "Computed property names are not allowed in enums." },
-        Computed_property_names_are_not_allowed_in_an_ambient_context: { code: 1165, category: DiagnosticCategory.Error, key: "Computed property names are not allowed in an ambient context." },
-        Computed_property_names_are_not_allowed_in_class_property_declarations: { code: 1166, category: DiagnosticCategory.Error, key: "Computed property names are not allowed in class property declarations." },
+        A_computed_property_name_in_an_ambient_context_must_directly_refer_to_a_built_in_symbol: { code: 1165, category: DiagnosticCategory.Error, key: "A computed property name in an ambient context must directly refer to a built-in symbol." },
+        A_computed_property_name_in_a_class_property_declaration_must_directly_refer_to_a_built_in_symbol: { code: 1166, category: DiagnosticCategory.Error, key: "A computed property name in a class property declaration must directly refer to a built-in symbol." },
         Computed_property_names_are_only_available_when_targeting_ECMAScript_6_and_higher: { code: 1167, category: DiagnosticCategory.Error, key: "Computed property names are only available when targeting ECMAScript 6 and higher." },
-        Computed_property_names_are_not_allowed_in_method_overloads: { code: 1168, category: DiagnosticCategory.Error, key: "Computed property names are not allowed in method overloads." },
-        Computed_property_names_are_not_allowed_in_interfaces: { code: 1169, category: DiagnosticCategory.Error, key: "Computed property names are not allowed in interfaces." },
-        Computed_property_names_are_not_allowed_in_type_literals: { code: 1170, category: DiagnosticCategory.Error, key: "Computed property names are not allowed in type literals." },
+        A_computed_property_name_in_a_method_overload_must_directly_refer_to_a_built_in_symbol: { code: 1168, category: DiagnosticCategory.Error, key: "A computed property name in a method overload must directly refer to a built-in symbol." },
+        A_computed_property_name_in_an_interface_must_directly_refer_to_a_built_in_symbol: { code: 1169, category: DiagnosticCategory.Error, key: "A computed property name in an interface must directly refer to a built-in symbol." },
+        A_computed_property_name_in_a_type_literal_must_directly_refer_to_a_built_in_symbol: { code: 1170, category: DiagnosticCategory.Error, key: "A computed property name in a type literal must directly refer to a built-in symbol." },
         A_comma_expression_is_not_allowed_in_a_computed_property_name: { code: 1171, category: DiagnosticCategory.Error, key: "A comma expression is not allowed in a computed property name." },
         extends_clause_already_seen: { code: 1172, category: DiagnosticCategory.Error, key: "'extends' clause already seen." },
         extends_clause_must_precede_implements_clause: { code: 1173, category: DiagnosticCategory.Error, key: "'extends' clause must precede 'implements' clause." },
@@ -166,7 +166,7 @@ module ts {
         Global_type_0_must_be_a_class_or_interface_type: { code: 2316, category: DiagnosticCategory.Error, key: "Global type '{0}' must be a class or interface type." },
         Global_type_0_must_have_1_type_parameter_s: { code: 2317, category: DiagnosticCategory.Error, key: "Global type '{0}' must have {1} type parameter(s)." },
         Cannot_find_global_type_0: { code: 2318, category: DiagnosticCategory.Error, key: "Cannot find global type '{0}'." },
-        Named_properties_0_of_types_1_and_2_are_not_identical: { code: 2319, category: DiagnosticCategory.Error, key: "Named properties '{0}' of types '{1}' and '{2}' are not identical." },
+        Named_property_0_of_types_1_and_2_are_not_identical: { code: 2319, category: DiagnosticCategory.Error, key: "Named property '{0}' of types '{1}' and '{2}' are not identical." },
         Interface_0_cannot_simultaneously_extend_types_1_and_2: { code: 2320, category: DiagnosticCategory.Error, key: "Interface '{0}' cannot simultaneously extend types '{1}' and '{2}'." },
         Excessive_stack_depth_comparing_types_0_and_1: { code: 2321, category: DiagnosticCategory.Error, key: "Excessive stack depth comparing types '{0}' and '{1}'." },
         Type_0_is_not_assignable_to_type_1: { code: 2322, category: DiagnosticCategory.Error, key: "Type '{0}' is not assignable to type '{1}'." },
@@ -188,7 +188,7 @@ module ts {
         Property_0_does_not_exist_on_type_1: { code: 2339, category: DiagnosticCategory.Error, key: "Property '{0}' does not exist on type '{1}'." },
         Only_public_and_protected_methods_of_the_base_class_are_accessible_via_the_super_keyword: { code: 2340, category: DiagnosticCategory.Error, key: "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: DiagnosticCategory.Error, key: "Property '{0}' is private and only accessible within class '{1}'." },
-        An_index_expression_argument_must_be_of_type_string_number_or_any: { code: 2342, category: DiagnosticCategory.Error, key: "An index expression argument must be of type 'string', 'number', or 'any'." },
+        An_index_expression_argument_must_be_of_type_string_number_symbol_or_any: { code: 2342, category: DiagnosticCategory.Error, key: "An index expression argument must be of type 'string', 'number', 'symbol, or 'any'." },
         Type_0_does_not_satisfy_the_constraint_1: { code: 2344, category: DiagnosticCategory.Error, key: "Type '{0}' does not satisfy the constraint '{1}'." },
         Argument_of_type_0_is_not_assignable_to_parameter_of_type_1: { code: 2345, category: DiagnosticCategory.Error, key: "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: DiagnosticCategory.Error, key: "Supplied parameters do not match any signature of call target." },
@@ -204,7 +204,7 @@ module ts {
         The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_property_or_indexer: { code: 2357, category: DiagnosticCategory.Error, key: "The operand of an increment or decrement operator must be a variable, property or indexer." },
         The_left_hand_side_of_an_instanceof_expression_must_be_of_type_any_an_object_type_or_a_type_parameter: { code: 2358, category: DiagnosticCategory.Error, key: "The left-hand side of an 'instanceof' expression must be of type 'any', an object type or a type parameter." },
         The_right_hand_side_of_an_instanceof_expression_must_be_of_type_any_or_of_a_type_assignable_to_the_Function_interface_type: { code: 2359, category: DiagnosticCategory.Error, key: "The right-hand side of an 'instanceof' expression must be of type 'any' or of a type assignable to the 'Function' interface type." },
-        The_left_hand_side_of_an_in_expression_must_be_of_types_any_string_or_number: { code: 2360, category: DiagnosticCategory.Error, key: "The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'." },
+        The_left_hand_side_of_an_in_expression_must_be_of_type_any_string_number_or_symbol: { code: 2360, category: DiagnosticCategory.Error, key: "The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'." },
         The_right_hand_side_of_an_in_expression_must_be_of_type_any_an_object_type_or_a_type_parameter: { code: 2361, category: DiagnosticCategory.Error, key: "The right-hand side of an 'in' expression must be of type 'any', an object type or a type parameter" },
         The_left_hand_side_of_an_arithmetic_operation_must_be_of_type_any_number_or_an_enum_type: { code: 2362, category: DiagnosticCategory.Error, key: "The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type." },
         The_right_hand_side_of_an_arithmetic_operation_must_be_of_type_any_number_or_an_enum_type: { code: 2363, category: DiagnosticCategory.Error, key: "The right-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type." },
@@ -299,20 +299,24 @@ module ts {
         Type_0_is_not_an_array_type: { code: 2461, category: DiagnosticCategory.Error, key: "Type '{0}' is not an array type." },
         A_rest_element_must_be_last_in_an_array_destructuring_pattern: { code: 2462, category: DiagnosticCategory.Error, key: "A rest element must be last in an array destructuring pattern" },
         A_binding_pattern_parameter_cannot_be_optional_in_an_implementation_signature: { code: 2463, category: DiagnosticCategory.Error, key: "A binding pattern parameter cannot be optional in an implementation signature." },
-        A_computed_property_name_must_be_of_type_string_number_or_any: { code: 2464, category: DiagnosticCategory.Error, key: "A computed property name must be of type 'string', 'number', or 'any'." },
+        A_computed_property_name_must_be_of_type_string_number_symbol_or_any: { code: 2464, category: DiagnosticCategory.Error, key: "A computed property name must be of type 'string', 'number', 'symbol', or 'any'." },
         this_cannot_be_referenced_in_a_computed_property_name: { code: 2465, category: DiagnosticCategory.Error, key: "'this' cannot be referenced in a computed property name." },
         super_cannot_be_referenced_in_a_computed_property_name: { code: 2466, category: DiagnosticCategory.Error, key: "'super' cannot be referenced in a computed property name." },
-        A_computed_property_name_cannot_reference_a_type_parameter_from_its_containing_type: { code: 2466, category: DiagnosticCategory.Error, key: "A computed property name cannot reference a type parameter from its containing type." },
-        Spread_operator_in_new_expressions_is_only_available_when_targeting_ECMAScript_6_and_higher: { code: 2468, category: DiagnosticCategory.Error, key: "Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher." },
-        Enum_declarations_must_all_be_const_or_non_const: { code: 2469, category: DiagnosticCategory.Error, key: "Enum declarations must all be const or non-const." },
-        In_const_enum_declarations_member_initializer_must_be_constant_expression: { code: 2470, category: DiagnosticCategory.Error, key: "In 'const' enum declarations member initializer must be constant expression." },
-        const_enums_can_only_be_used_in_property_or_index_access_expressions_or_the_right_hand_side_of_an_import_declaration_or_export_assignment: { code: 2471, category: DiagnosticCategory.Error, key: "'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment." },
-        A_const_enum_member_can_only_be_accessed_using_a_string_literal: { code: 2472, category: DiagnosticCategory.Error, key: "A const enum member can only be accessed using a string literal." },
-        const_enum_member_initializer_was_evaluated_to_a_non_finite_value: { code: 2473, category: DiagnosticCategory.Error, key: "'const' enum member initializer was evaluated to a non-finite value." },
-        const_enum_member_initializer_was_evaluated_to_disallowed_value_NaN: { code: 2474, category: DiagnosticCategory.Error, key: "'const' enum member initializer was evaluated to disallowed value 'NaN'." },
-        Property_0_does_not_exist_on_const_enum_1: { code: 2475, category: DiagnosticCategory.Error, key: "Property '{0}' does not exist on 'const' enum '{1}'." },
-        let_is_not_allowed_to_be_used_as_a_name_in_let_or_const_declarations: { code: 2476, category: DiagnosticCategory.Error, key: "'let' is not allowed to be used as a name in 'let' or 'const' declarations." },
-        Cannot_initialize_outer_scoped_variable_0_in_the_same_scope_as_block_scoped_declaration_1: { code: 2477, category: DiagnosticCategory.Error, key: "Cannot initialize outer scoped variable '{0}' in the same scope as block scoped declaration '{1}'." },
+        A_computed_property_name_cannot_reference_a_type_parameter_from_its_containing_type: { code: 2467, category: DiagnosticCategory.Error, key: "A computed property name cannot reference a type parameter from its containing type." },
+        Cannot_find_global_value_0: { code: 2468, category: DiagnosticCategory.Error, key: "Cannot find global value '{0}'." },
+        The_0_operator_cannot_be_applied_to_type_symbol: { code: 2469, category: DiagnosticCategory.Error, key: "The '{0}' operator cannot be applied to type 'symbol'." },
+        Symbol_reference_does_not_refer_to_the_global_Symbol_constructor_object: { code: 2470, category: DiagnosticCategory.Error, key: "'Symbol' reference does not refer to the global Symbol constructor object." },
+        A_computed_property_name_of_the_form_0_must_be_of_type_symbol: { code: 2471, category: DiagnosticCategory.Error, key: "A computed property name of the form '{0}' must be of type 'symbol'." },
+        Spread_operator_in_new_expressions_is_only_available_when_targeting_ECMAScript_6_and_higher: { code: 2472, category: DiagnosticCategory.Error, key: "Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher." },
+        Enum_declarations_must_all_be_const_or_non_const: { code: 2473, category: DiagnosticCategory.Error, key: "Enum declarations must all be const or non-const." },
+        In_const_enum_declarations_member_initializer_must_be_constant_expression: { code: 2474, category: DiagnosticCategory.Error, key: "In 'const' enum declarations member initializer must be constant expression." },
+        const_enums_can_only_be_used_in_property_or_index_access_expressions_or_the_right_hand_side_of_an_import_declaration_or_export_assignment: { code: 2475, category: DiagnosticCategory.Error, key: "'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment." },
+        A_const_enum_member_can_only_be_accessed_using_a_string_literal: { code: 2476, category: DiagnosticCategory.Error, key: "A const enum member can only be accessed using a string literal." },
+        const_enum_member_initializer_was_evaluated_to_a_non_finite_value: { code: 2477, category: DiagnosticCategory.Error, key: "'const' enum member initializer was evaluated to a non-finite value." },
+        const_enum_member_initializer_was_evaluated_to_disallowed_value_NaN: { code: 2478, category: DiagnosticCategory.Error, key: "'const' enum member initializer was evaluated to disallowed value 'NaN'." },
+        Property_0_does_not_exist_on_const_enum_1: { code: 2479, category: DiagnosticCategory.Error, key: "Property '{0}' does not exist on 'const' enum '{1}'." },
+        let_is_not_allowed_to_be_used_as_a_name_in_let_or_const_declarations: { code: 2480, category: DiagnosticCategory.Error, key: "'let' is not allowed to be used as a name in 'let' or 'const' declarations." },
+        Cannot_initialize_outer_scoped_variable_0_in_the_same_scope_as_block_scoped_declaration_1: { code: 2481, category: DiagnosticCategory.Error, key: "Cannot initialize outer scoped variable '{0}' in the same scope as block scoped declaration '{1}'." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: DiagnosticCategory.Error, key: "Import declaration '{0}' is using private name '{1}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: { code: 4002, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
         Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1: { code: 4004, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported interface has or is using private name '{1}'." },

src/compiler/diagnosticMessages.json

@@ -483,11 +483,11 @@
         "category": "Error",
         "code": 1164
     },
-    "Computed property names are not allowed in an ambient context.": {
+    "A computed property name in an ambient context must directly refer to a built-in symbol.": {
         "category": "Error",
         "code": 1165
     },
-    "Computed property names are not allowed in class property declarations.": {
+    "A computed property name in a class property declaration must directly refer to a built-in symbol.": {
         "category": "Error",
         "code": 1166
     },
@@ -495,15 +495,15 @@
         "category": "Error",
         "code": 1167
     },
-    "Computed property names are not allowed in method overloads.": {
+    "A computed property name in a method overload must directly refer to a built-in symbol.": {
         "category": "Error",
         "code": 1168
     },
-    "Computed property names are not allowed in interfaces.": {
+    "A computed property name in an interface must directly refer to a built-in symbol.": {
         "category": "Error",
         "code": 1169
     },
-    "Computed property names are not allowed in type literals.": {
+    "A computed property name in a type literal must directly refer to a built-in symbol.": {
         "category": "Error",
         "code": 1170
     },
@@ -656,7 +656,7 @@
         "category": "Error",
         "code": 2318
     },
-    "Named properties '{0}' of types '{1}' and '{2}' are not identical.": {
+    "Named property '{0}' of types '{1}' and '{2}' are not identical.": {
         "category": "Error",
         "code": 2319
     },
@@ -744,7 +744,7 @@
         "category": "Error",
         "code": 2341
     },
-    "An index expression argument must be of type 'string', 'number', or 'any'.": {
+    "An index expression argument must be of type 'string', 'number', 'symbol, or 'any'.": {
         "category": "Error",
         "code": 2342
     },
@@ -808,7 +808,7 @@
         "category": "Error",
         "code": 2359
     },
-    "The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.": {
+    "The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.": {
         "category": "Error",
         "code": 2360
     },
@@ -1188,7 +1188,7 @@
         "category": "Error",
         "code": 2463
     },
-    "A computed property name must be of type 'string', 'number', or 'any'.": {
+    "A computed property name must be of type 'string', 'number', 'symbol', or 'any'.": {
         "category": "Error",
         "code": 2464
     },
@@ -1202,48 +1202,64 @@
     },
     "A computed property name cannot reference a type parameter from its containing type.": {
         "category": "Error",
-        "code": 2466
+        "code": 2467
     },
-    "Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher.": {
+    "Cannot find global value '{0}'.": {
         "category": "Error",
         "code": 2468
     },
-    "Enum declarations must all be const or non-const.": {
+    "The '{0}' operator cannot be applied to type 'symbol'.": {
         "category": "Error",
         "code": 2469
     },
-    "In 'const' enum declarations member initializer must be constant expression.": {
+    "'Symbol' reference does not refer to the global Symbol constructor object.": {
         "category": "Error",
         "code": 2470
     },
-    "'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.": {
+    "A computed property name of the form '{0}' must be of type 'symbol'.": {
         "category": "Error",
         "code": 2471
     },
-    "A const enum member can only be accessed using a string literal.": {
+    "Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher.": {
         "category": "Error",
         "code": 2472
     },
-    "'const' enum member initializer was evaluated to a non-finite value.": {
+    "Enum declarations must all be const or non-const.": {
         "category": "Error",
         "code": 2473
     },
-    "'const' enum member initializer was evaluated to disallowed value 'NaN'.": {
+    "In 'const' enum declarations member initializer must be constant expression.": {
         "category": "Error",
         "code": 2474
     },
-    "Property '{0}' does not exist on 'const' enum '{1}'.": {
+    "'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.": {
         "category": "Error",
         "code": 2475
     },
-    "'let' is not allowed to be used as a name in 'let' or 'const' declarations.": {
+    "A const enum member can only be accessed using a string literal.": {
         "category": "Error",
         "code": 2476
     },
-    "Cannot initialize outer scoped variable '{0}' in the same scope as block scoped declaration '{1}'.": {
+    "'const' enum member initializer was evaluated to a non-finite value.": {
         "category": "Error",
         "code": 2477
     },
+    "'const' enum member initializer was evaluated to disallowed value 'NaN'.": {
+        "category": "Error",
+        "code": 2478
+    },
+    "Property '{0}' does not exist on 'const' enum '{1}'.": {
+        "category": "Error",
+        "code": 2479
+    },
+    "'let' is not allowed to be used as a name in 'let' or 'const' declarations.": {
+        "category": "Error",
+        "code": 2480
+    },
+    "Cannot initialize outer scoped variable '{0}' in the same scope as block scoped declaration '{1}'.": {
+        "category": "Error",
+        "code": 2481
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

src/compiler/emitter.ts

@@ -275,7 +275,7 @@ module ts {
         var firstAccessor: AccessorDeclaration;
         var getAccessor: AccessorDeclaration;
         var setAccessor: AccessorDeclaration;
-        if (accessor.name.kind === SyntaxKind.ComputedPropertyName) {
+        if (hasDynamicName(accessor)) {
             firstAccessor = accessor;
             if (accessor.kind === SyntaxKind.GetAccessor) {
                 getAccessor = accessor;
@@ -289,19 +289,22 @@ module ts {
         }
         else {
             forEach(node.members,(member: Declaration) => {
-                if ((member.kind === SyntaxKind.GetAccessor || member.kind === SyntaxKind.SetAccessor) &&
-                    (<Identifier>member.name).text === (<Identifier>accessor.name).text &&
-                    (member.flags & NodeFlags.Static) === (accessor.flags & NodeFlags.Static)) {
-                    if (!firstAccessor) {
-                        firstAccessor = <AccessorDeclaration>member;
-                    }
+                if ((member.kind === SyntaxKind.GetAccessor || member.kind === SyntaxKind.SetAccessor)
+                    && (member.flags & NodeFlags.Static) === (accessor.flags & NodeFlags.Static)) {
+                    var memberName = getPropertyNameForPropertyNameNode(member.name);
+                    var accessorName = getPropertyNameForPropertyNameNode(accessor.name);
+                    if (memberName === accessorName) {
+                        if (!firstAccessor) {
+                            firstAccessor = <AccessorDeclaration>member;
+                        }
 
-                    if (member.kind === SyntaxKind.GetAccessor && !getAccessor) {
-                        getAccessor = <AccessorDeclaration>member;
-                    }
+                        if (member.kind === SyntaxKind.GetAccessor && !getAccessor) {
+                            getAccessor = <AccessorDeclaration>member;
+                        }
 
-                    if (member.kind === SyntaxKind.SetAccessor && !setAccessor) {
-                        setAccessor = <AccessorDeclaration>member;
+                        if (member.kind === SyntaxKind.SetAccessor && !setAccessor) {
+                            setAccessor = <AccessorDeclaration>member;
+                        }
                     }
                 }
             });
@@ -579,6 +582,7 @@ module ts {
                 case SyntaxKind.StringKeyword:
                 case SyntaxKind.NumberKeyword:
                 case SyntaxKind.BooleanKeyword:
+                case SyntaxKind.SymbolKeyword:
                 case SyntaxKind.VoidKeyword:
                 case SyntaxKind.StringLiteral:
                     return writeTextOfNode(currentSourceFile, type);

src/compiler/parser.ts

@@ -2593,6 +2593,7 @@ module ts {
                 case SyntaxKind.StringKeyword:
                 case SyntaxKind.NumberKeyword:
                 case SyntaxKind.BooleanKeyword:
+                case SyntaxKind.SymbolKeyword:
                     // If these are followed by a dot, then parse these out as a dotted type reference instead.
                     var node = tryParse(parseKeywordAndNoDot);
                     return node || parseTypeReference();
@@ -2617,6 +2618,7 @@ module ts {
                 case SyntaxKind.StringKeyword:
                 case SyntaxKind.NumberKeyword:
                 case SyntaxKind.BooleanKeyword:
+                case SyntaxKind.SymbolKeyword:
                 case SyntaxKind.VoidKeyword:
                 case SyntaxKind.TypeOfKeyword:
                 case SyntaxKind.OpenBraceToken:

src/compiler/scanner.ts

@@ -82,6 +82,7 @@ module ts {
         "string": SyntaxKind.StringKeyword,
         "super": SyntaxKind.SuperKeyword,
         "switch": SyntaxKind.SwitchKeyword,
+        "symbol": SyntaxKind.SymbolKeyword,
         "this": SyntaxKind.ThisKeyword,
         "throw": SyntaxKind.ThrowKeyword,
         "true": SyntaxKind.TrueKeyword,

src/compiler/types.ts

@@ -140,6 +140,7 @@ module ts {
         NumberKeyword,
         SetKeyword,
         StringKeyword,
+        SymbolKeyword,
         TypeKeyword,
 
         // Parse tree nodes
@@ -1298,9 +1299,10 @@ module ts {
         ObjectLiteral           = 0x00020000,  // Originates in an object literal
         ContainsUndefinedOrNull = 0x00040000,  // Type is or contains Undefined or Null type
         ContainsObjectLiteral   = 0x00080000,  // Type is or contains object literal type
+        ESSymbol                = 0x00100000,  // Type of symbol primitive introduced in ES6
 
-        Intrinsic = Any | String | Number | Boolean | Void | Undefined | Null,
-        Primitive = String | Number | Boolean | Void | Undefined | Null | StringLiteral | Enum,
+        Intrinsic = Any | String | Number | Boolean | ESSymbol | Void | Undefined | Null,
+        Primitive = String | Number | Boolean | ESSymbol | Void | Undefined | Null | StringLiteral | Enum,
         StringLike = String | StringLiteral,
         NumberLike = Number | Enum,
         ObjectType = Class | Interface | Reference | Tuple | Anonymous,

src/compiler/utilities.ts

@@ -835,6 +835,54 @@ module ts {
         return SyntaxKind.FirstTriviaToken <= token && token <= SyntaxKind.LastTriviaToken;
     }
 
+    /**
+     * A declaration has a dynamic name if both of the following are true:
+     *   1. The declaration has a computed property name
+     *   2. The computed name is *not* expressed as Symbol.<name>, where name
+     *      is a property of the Symbol constructor that denotes a built in
+     *      Symbol.
+     */
+    export function hasDynamicName(declaration: Declaration): boolean {
+        return declaration.name &&
+            declaration.name.kind === SyntaxKind.ComputedPropertyName &&
+            !isWellKnownSymbolSyntactically((<ComputedPropertyName>declaration.name).expression);
+    }
+
+    /**
+     * Checks if the expression is of the form:
+     *    Symbol.name
+     * where Symbol is literally the word "Symbol", and name is any identifierName
+     */
+    export function isWellKnownSymbolSyntactically(node: Expression): boolean {
+        return node.kind === SyntaxKind.PropertyAccessExpression && isESSymbolIdentifier((<PropertyAccessExpression>node).expression);
+    }
+
+    export function getPropertyNameForPropertyNameNode(name: DeclarationName): string {
+        if (name.kind === SyntaxKind.Identifier || name.kind === SyntaxKind.StringLiteral || name.kind === SyntaxKind.NumericLiteral) {
+            return (<Identifier | LiteralExpression>name).text;
+        }
+        if (name.kind === SyntaxKind.ComputedPropertyName) {
+            var nameExpression = (<ComputedPropertyName>name).expression;
+            if (isWellKnownSymbolSyntactically(nameExpression)) {
+                var rightHandSideName = (<PropertyAccessExpression>nameExpression).name.text;
+                return getPropertyNameForKnownSymbolName(rightHandSideName);
+            }
+        }
+
+        return undefined;
+    }
+
+    export function getPropertyNameForKnownSymbolName(symbolName: string): string {
+        return "__@" + symbolName;
+    }
+
+    /**
+     * Includes the word "Symbol" with unicode escapes
+     */
+    export function isESSymbolIdentifier(node: Node): boolean {
+        return node.kind === SyntaxKind.Identifier && (<Identifier>node).text === "Symbol";
+    }
+
     export function isModifier(token: SyntaxKind): boolean {
         switch (token) {
             case SyntaxKind.PublicKeyword:

src/lib/es6.d.ts

@@ -1,4 +1,4 @@
-declare type PropertyKey = string | number | Symbol;
+declare type PropertyKey = string | number | symbol;
 
 interface Symbol {
     /** Returns a string representation of an object. */
@@ -7,7 +7,7 @@ interface Symbol {
     /** Returns the primitive value of the specified object. */
     valueOf(): Object;
 
-    // [Symbol.toStringTag]: string;
+    [Symbol.toStringTag]: string;
 }
 
 interface SymbolConstructor {
@@ -20,21 +20,21 @@ interface SymbolConstructor {
       * Returns a new unique Symbol value.
       * @param  description Description of the new Symbol object.
       */
-    (description?: string|number): Symbol;
+    (description?: string|number): symbol;
 
     /**
       * Returns a Symbol object from the global symbol registry matching the given key if found. 
       * Otherwise, returns a new symbol with this key.
       * @param key key to search for.
       */
-    for(key: string): Symbol;
+    for(key: string): symbol;
 
     /**
       * Returns a key from the global symbol registry matching the given Symbol if found. 
       * Otherwise, returns a undefined.
       * @param sym Symbol to find the key for.
       */
-    keyFor(sym: Symbol): string;
+    keyFor(sym: symbol): string;
 
     // Well-known Symbols
 
@@ -42,42 +42,42 @@ interface SymbolConstructor {
       * A method that determines if a constructor object recognizes an object as one of the 
       * constructor’s instances. Called by the semantics of the instanceof operator. 
       */
-    hasInstance: Symbol;
+    hasInstance: symbol;
 
     /** 
       * A Boolean value that if true indicates that an object should flatten to its array elements
       * by Array.prototype.concat.
       */
-    isConcatSpreadable: Symbol;
+    isConcatSpreadable: symbol;
 
     /** 
       * A Boolean value that if true indicates that an object may be used as a regular expression. 
       */
-    isRegExp: Symbol;
+    isRegExp: symbol;
 
     /** 
       * A method that returns the default iterator for an object.Called by the semantics of the 
       * for-of statement. 
       */
-    iterator: Symbol;
+    iterator: symbol;
 
     /** 
       * A method that converts an object to a corresponding primitive value.Called by the ToPrimitive
       * abstract operation. 
       */
-    toPrimitive: Symbol;
+    toPrimitive: symbol;
 
     /** 
       * A String value that is used in the creation of the default string description of an object. 
       * Called by the built- in method Object.prototype.toString. 
       */
-    toStringTag: Symbol;
+    toStringTag: symbol;
 
     /** 
       * An Object whose own property names are property names that are excluded from the with 
       * environment bindings of the associated objects.
       */
-    unscopables: Symbol;
+    unscopables: symbol;
 }
 declare var Symbol: SymbolConstructor;
 
@@ -108,7 +108,7 @@ interface ObjectConstructor {
       * Returns an array of all symbol properties found directly on object o.
       * @param o Object to retrieve the symbols from.
       */
-    getOwnPropertySymbols(o: any): Symbol[];
+    getOwnPropertySymbols(o: any): symbol[];
 
     /**
       *  Returns true if the values are the same value, false otherwise.
@@ -230,7 +230,7 @@ interface ArrayLike<T> {
 
 interface Array<T> {
     /** Iterator */
-    // [Symbol.iterator] (): Iterator<T>;
+    [Symbol.iterator] (): Iterator<T>;
 
     /** 
       * Returns an array of key, value pairs for every entry in the array
@@ -329,7 +329,7 @@ interface ArrayConstructor {
 
 interface String {
     /** Iterator */
-    // [Symbol.iterator] (): Iterator<string>;
+    [Symbol.iterator] (): Iterator<string>;
 
     /**
       * Returns a nonnegative integer Number less than 1114112 (0x110000) that is the code point 
@@ -447,12 +447,12 @@ interface IteratorResult<T> {
 }
 
 interface Iterator<T> {
-    //[Symbol.iterator](): Iterator<T>;
+    [Symbol.iterator](): Iterator<T>;
     next(): IteratorResult<T>;
 }
 
 interface Iterable<T> {
-  //[Symbol.iterator](): Iterator<T>;
+    [Symbol.iterator](): Iterator<T>;
 }
 
 interface GeneratorFunction extends Function {
@@ -474,7 +474,7 @@ interface Generator<T> extends Iterator<T> {
     next(value?: any): IteratorResult<T>;
     throw (exception: any): IteratorResult<T>;
     return (value: T): IteratorResult<T>;
-    // [Symbol.toStringTag]: string;
+    [Symbol.toStringTag]: string;
 }
 
 interface Math {
@@ -588,11 +588,11 @@ interface Math {
       */
     cbrt(x: number): number;
 
-    // [Symbol.toStringTag]: string;
+    [Symbol.toStringTag]: string;
 }
 
 interface RegExp {
-    // [Symbol.isRegExp]: boolean;
+    [Symbol.isRegExp]: boolean;
 
     /** 
       * Matches a string with a regular expression, and returns an array containing the results of 
@@ -649,8 +649,8 @@ interface Map<K, V> {
     set(key: K, value?: V): Map<K, V>;
     size: number;
     values(): Iterator<V>;
-    // [Symbol.iterator]():Iterator<[K,V]>;
-    // [Symbol.toStringTag]: string;
+    [Symbol.iterator]():Iterator<[K,V]>;
+    [Symbol.toStringTag]: string;
 }
 
 interface MapConstructor {
@@ -666,7 +666,7 @@ interface WeakMap<K, V> {
     get(key: K): V;
     has(key: K): boolean;
     set(key: K, value?: V): WeakMap<K, V>;
-    // [Symbol.toStringTag]: string;
+    [Symbol.toStringTag]: string;
 }
 
 interface WeakMapConstructor {
@@ -686,8 +686,8 @@ interface Set<T> {
     keys(): Iterator<T>;
     size: number;
     values(): Iterator<T>;
-    // [Symbol.iterator]():Iterator<T>;
-    // [Symbol.toStringTag]: string;
+    [Symbol.iterator]():Iterator<T>;
+    [Symbol.toStringTag]: string;
 }
 
 interface SetConstructor {
@@ -702,7 +702,7 @@ interface WeakSet<T> {
     clear(): void;
     delete(value: T): boolean;
     has(value: T): boolean;
-    // [Symbol.toStringTag]: string;
+    [Symbol.toStringTag]: string;
 }
 
 interface WeakSetConstructor {
@@ -713,7 +713,7 @@ interface WeakSetConstructor {
 declare var WeakSet: WeakSetConstructor;
 
 interface JSON {
-    // [Symbol.toStringTag]: string;
+    [Symbol.toStringTag]: string;
 }
 
 /**
@@ -733,7 +733,7 @@ interface ArrayBuffer {
       */
     slice(begin: number, end?: number): ArrayBuffer;
 
-    // [Symbol.toStringTag]: string;
+    [Symbol.toStringTag]: string;
 }
 
 interface ArrayBufferConstructor {
@@ -870,7 +870,7 @@ interface DataView {
       */
     setUint32(byteOffset: number, value: number, littleEndian: boolean): void;
 
-    // [Symbol.toStringTag]: string;
+    [Symbol.toStringTag]: string;
 }
 
 interface DataViewConstructor {
@@ -1137,7 +1137,7 @@ interface Int8Array {
     values(): Iterator<number>;
 
     [index: number]: number;
-    // [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator] (): Iterator<number>;
 }
 
 interface Int8ArrayConstructor {
@@ -1427,7 +1427,7 @@ interface Uint8Array {
     values(): Iterator<number>;
 
     [index: number]: number;
-    // [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator] (): Iterator<number>;
 }
 
 interface Uint8ArrayConstructor {
@@ -1717,7 +1717,7 @@ interface Uint8ClampedArray {
     values(): Iterator<number>;
 
     [index: number]: number;
-    // [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator] (): Iterator<number>;
 }
 
 interface Uint8ClampedArrayConstructor {
@@ -2007,7 +2007,7 @@ interface Int16Array {
     values(): Iterator<number>;
 
     [index: number]: number;
-    // [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator] (): Iterator<number>;
 }
 
 interface Int16ArrayConstructor {
@@ -2297,7 +2297,7 @@ interface Uint16Array {
     values(): Iterator<number>;
 
     [index: number]: number;
-    // [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator] (): Iterator<number>;
 }
 
 interface Uint16ArrayConstructor {
@@ -2587,7 +2587,7 @@ interface Int32Array {
     values(): Iterator<number>;
 
     [index: number]: number;
-    // [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator] (): Iterator<number>;
 }
 
 interface Int32ArrayConstructor {
@@ -2877,7 +2877,7 @@ interface Uint32Array {
     values(): Iterator<number>;
 
     [index: number]: number;
-    // [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator] (): Iterator<number>;
 }
 
 interface Uint32ArrayConstructor {
@@ -3167,7 +3167,7 @@ interface Float32Array {
     values(): Iterator<number>;
 
     [index: number]: number;
-    // [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator] (): Iterator<number>;
 }
 
 interface Float32ArrayConstructor {
@@ -3457,7 +3457,7 @@ interface Float64Array {
     values(): Iterator<number>;
 
     [index: number]: number;
-    // [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator] (): Iterator<number>;
 }
 
 interface Float64ArrayConstructor {
@@ -3521,7 +3521,7 @@ declare var Reflect: {
     getOwnPropertyDescriptor(target: any, propertyKey: PropertyKey): PropertyDescriptor;
     getPrototypeOf(target: any): any;
     has(target: any, propertyKey: string): boolean;
-    has(target: any, propertyKey: Symbol): boolean;
+    has(target: any, propertyKey: symbol): boolean;
     isExtensible(target: any): boolean;
     ownKeys(target: any): Array<PropertyKey>;
     preventExtensions(target: any): boolean;

src/services/formatting/tokenRange.ts

@@ -134,7 +134,7 @@ module ts.formatting {
             static UnaryPredecrementExpressions = TokenRange.FromTokens([SyntaxKind.Identifier, SyntaxKind.OpenParenToken, SyntaxKind.ThisKeyword, SyntaxKind.NewKeyword]);
             static UnaryPostdecrementExpressions = TokenRange.FromTokens([SyntaxKind.Identifier, SyntaxKind.CloseParenToken, SyntaxKind.CloseBracketToken, SyntaxKind.NewKeyword]);
             static Comments = TokenRange.FromTokens([SyntaxKind.SingleLineCommentTrivia, SyntaxKind.MultiLineCommentTrivia]);
-            static TypeNames = TokenRange.FromTokens([SyntaxKind.Identifier, SyntaxKind.NumberKeyword, SyntaxKind.StringKeyword, SyntaxKind.BooleanKeyword, SyntaxKind.VoidKeyword, SyntaxKind.AnyKeyword]);
+            static TypeNames = TokenRange.FromTokens([SyntaxKind.Identifier, SyntaxKind.NumberKeyword, SyntaxKind.StringKeyword, SyntaxKind.BooleanKeyword, SyntaxKind.SymbolKeyword, SyntaxKind.VoidKeyword, SyntaxKind.AnyKeyword]);
         }
     }
 }

src/services/navigationBar.ts

@@ -97,8 +97,7 @@ module ts.NavigationBar {
         function sortNodes(nodes: Node[]): Node[] {
             return nodes.slice(0).sort((n1: Declaration, n2: Declaration) => {
                 if (n1.name && n2.name) {
-                    // TODO(jfreeman): How do we sort declarations with computed names?
-                    return (<Identifier>n1.name).text.localeCompare((<Identifier>n2.name).text);
+                    return getPropertyNameForPropertyNameNode(n1.name).localeCompare(getPropertyNameForPropertyNameNode(n2.name));
                 }
                 else if (n1.name) {
                     return 1;
@@ -426,7 +425,7 @@ module ts.NavigationBar {
                     // Add the constructor parameters in as children of the class (for property parameters).
                     // Note that *all* parameters will be added to the nodes array, but parameters that
                     // are not properties will be filtered out later by createChildItem.
-                    var nodes: Node[] = removeComputedProperties(node);
+                    var nodes: Node[] = removeDynamicallyNamedProperties(node);
                     if (constructor) {
                         nodes.push.apply(nodes, constructor.parameters);
                     }
@@ -455,7 +454,7 @@ module ts.NavigationBar {
             }
 
             function createIterfaceItem(node: InterfaceDeclaration): ts.NavigationBarItem {
-                var childItems = getItemsWorker(sortNodes(removeComputedProperties(node)), createChildItem);
+                var childItems = getItemsWorker(sortNodes(removeDynamicallyNamedProperties(node)), createChildItem);
                 return getNavigationBarItem(
                     node.name.text,
                     ts.ScriptElementKind.interfaceElement,
@@ -466,10 +465,17 @@ module ts.NavigationBar {
             }
         }
 
-        function removeComputedProperties(node: ClassDeclaration | InterfaceDeclaration | EnumDeclaration): Declaration[] {
+        function removeComputedProperties(node: EnumDeclaration): Declaration[] {
             return filter<Declaration>(node.members, member => member.name === undefined || member.name.kind !== SyntaxKind.ComputedPropertyName);
         }
 
+        /**
+         * Like removeComputedProperties, but retains the properties with well known symbol names
+         */
+        function removeDynamicallyNamedProperties(node: ClassDeclaration | InterfaceDeclaration): Declaration[]{
+            return filter<Declaration>(node.members, member => !hasDynamicName(member));
+        }
+
         function getInnermostModule(node: ModuleDeclaration): ModuleDeclaration {
             while (node.body.kind === SyntaxKind.ModuleDeclaration) {
                 node = <ModuleDeclaration>node.body;

src/services/services.ts

@@ -5797,7 +5797,8 @@ module ts {
                     else if (token === SyntaxKind.AnyKeyword ||
                              token === SyntaxKind.StringKeyword ||
                              token === SyntaxKind.NumberKeyword ||
-                             token === SyntaxKind.BooleanKeyword) {
+                             token === SyntaxKind.BooleanKeyword ||
+                             token === SyntaxKind.SymbolKeyword) {
                         if (angleBracketStack > 0 && !syntacticClassifierAbsent) {
                             // If it looks like we're could be in something generic, don't classify this 
                             // as a keyword.  We may just get overwritten by the syntactic classifier,

tests/baselines/reference/APISample_compile.js

@@ -179,110 +179,111 @@ declare module "typescript" {
         NumberKeyword = 117,
         SetKeyword = 118,
         StringKeyword = 119,
-        TypeKeyword = 120,
-        QualifiedName = 121,
-        ComputedPropertyName = 122,
-        TypeParameter = 123,
-        Parameter = 124,
-        PropertySignature = 125,
-        PropertyDeclaration = 126,
-        MethodSignature = 127,
-        MethodDeclaration = 128,
-        Constructor = 129,
-        GetAccessor = 130,
-        SetAccessor = 131,
-        CallSignature = 132,
-        ConstructSignature = 133,
-        IndexSignature = 134,
-        TypeReference = 135,
-        FunctionType = 136,
-        ConstructorType = 137,
-        TypeQuery = 138,
-        TypeLiteral = 139,
-        ArrayType = 140,
-        TupleType = 141,
-        UnionType = 142,
-        ParenthesizedType = 143,
-        ObjectBindingPattern = 144,
-        ArrayBindingPattern = 145,
-        BindingElement = 146,
-        ArrayLiteralExpression = 147,
-        ObjectLiteralExpression = 148,
-        PropertyAccessExpression = 149,
-        ElementAccessExpression = 150,
-        CallExpression = 151,
-        NewExpression = 152,
-        TaggedTemplateExpression = 153,
-        TypeAssertionExpression = 154,
-        ParenthesizedExpression = 155,
-        FunctionExpression = 156,
-        ArrowFunction = 157,
-        DeleteExpression = 158,
-        TypeOfExpression = 159,
-        VoidExpression = 160,
-        PrefixUnaryExpression = 161,
-        PostfixUnaryExpression = 162,
-        BinaryExpression = 163,
-        ConditionalExpression = 164,
-        TemplateExpression = 165,
-        YieldExpression = 166,
-        SpreadElementExpression = 167,
-        OmittedExpression = 168,
-        TemplateSpan = 169,
-        Block = 170,
-        VariableStatement = 171,
-        EmptyStatement = 172,
-        ExpressionStatement = 173,
-        IfStatement = 174,
-        DoStatement = 175,
-        WhileStatement = 176,
-        ForStatement = 177,
-        ForInStatement = 178,
-        ContinueStatement = 179,
-        BreakStatement = 180,
-        ReturnStatement = 181,
-        WithStatement = 182,
-        SwitchStatement = 183,
-        LabeledStatement = 184,
-        ThrowStatement = 185,
-        TryStatement = 186,
-        DebuggerStatement = 187,
-        VariableDeclaration = 188,
-        VariableDeclarationList = 189,
-        FunctionDeclaration = 190,
-        ClassDeclaration = 191,
-        InterfaceDeclaration = 192,
-        TypeAliasDeclaration = 193,
-        EnumDeclaration = 194,
-        ModuleDeclaration = 195,
-        ModuleBlock = 196,
-        ImportDeclaration = 197,
-        ExportAssignment = 198,
-        ExternalModuleReference = 199,
-        CaseClause = 200,
-        DefaultClause = 201,
-        HeritageClause = 202,
-        CatchClause = 203,
-        PropertyAssignment = 204,
-        ShorthandPropertyAssignment = 205,
-        EnumMember = 206,
-        SourceFile = 207,
-        SyntaxList = 208,
-        Count = 209,
+        SymbolKeyword = 120,
+        TypeKeyword = 121,
+        QualifiedName = 122,
+        ComputedPropertyName = 123,
+        TypeParameter = 124,
+        Parameter = 125,
+        PropertySignature = 126,
+        PropertyDeclaration = 127,
+        MethodSignature = 128,
+        MethodDeclaration = 129,
+        Constructor = 130,
+        GetAccessor = 131,
+        SetAccessor = 132,
+        CallSignature = 133,
+        ConstructSignature = 134,
+        IndexSignature = 135,
+        TypeReference = 136,
+        FunctionType = 137,
+        ConstructorType = 138,
+        TypeQuery = 139,
+        TypeLiteral = 140,
+        ArrayType = 141,
+        TupleType = 142,
+        UnionType = 143,
+        ParenthesizedType = 144,
+        ObjectBindingPattern = 145,
+        ArrayBindingPattern = 146,
+        BindingElement = 147,
+        ArrayLiteralExpression = 148,
+        ObjectLiteralExpression = 149,
+        PropertyAccessExpression = 150,
+        ElementAccessExpression = 151,
+        CallExpression = 152,
+        NewExpression = 153,
+        TaggedTemplateExpression = 154,
+        TypeAssertionExpression = 155,
+        ParenthesizedExpression = 156,
+        FunctionExpression = 157,
+        ArrowFunction = 158,
+        DeleteExpression = 159,
+        TypeOfExpression = 160,
+        VoidExpression = 161,
+        PrefixUnaryExpression = 162,
+        PostfixUnaryExpression = 163,
+        BinaryExpression = 164,
+        ConditionalExpression = 165,
+        TemplateExpression = 166,
+        YieldExpression = 167,
+        SpreadElementExpression = 168,
+        OmittedExpression = 169,
+        TemplateSpan = 170,
+        Block = 171,
+        VariableStatement = 172,
+        EmptyStatement = 173,
+        ExpressionStatement = 174,
+        IfStatement = 175,
+        DoStatement = 176,
+        WhileStatement = 177,
+        ForStatement = 178,
+        ForInStatement = 179,
+        ContinueStatement = 180,
+        BreakStatement = 181,
+        ReturnStatement = 182,
+        WithStatement = 183,
+        SwitchStatement = 184,
+        LabeledStatement = 185,
+        ThrowStatement = 186,
+        TryStatement = 187,
+        DebuggerStatement = 188,
+        VariableDeclaration = 189,
+        VariableDeclarationList = 190,
+        FunctionDeclaration = 191,
+        ClassDeclaration = 192,
+        InterfaceDeclaration = 193,
+        TypeAliasDeclaration = 194,
+        EnumDeclaration = 195,
+        ModuleDeclaration = 196,
+        ModuleBlock = 197,
+        ImportDeclaration = 198,
+        ExportAssignment = 199,
+        ExternalModuleReference = 200,
+        CaseClause = 201,
+        DefaultClause = 202,
+        HeritageClause = 203,
+        CatchClause = 204,
+        PropertyAssignment = 205,
+        ShorthandPropertyAssignment = 206,
+        EnumMember = 207,
+        SourceFile = 208,
+        SyntaxList = 209,
+        Count = 210,
         FirstAssignment = 52,
         LastAssignment = 63,
         FirstReservedWord = 65,
         LastReservedWord = 100,
         FirstKeyword = 65,
-        LastKeyword = 120,
+        LastKeyword = 121,
         FirstFutureReservedWord = 101,
         LastFutureReservedWord = 109,
-        FirstTypeNode = 135,
-        LastTypeNode = 143,
+        FirstTypeNode = 136,
+        LastTypeNode = 144,
         FirstPunctuation = 14,
         LastPunctuation = 63,
         FirstToken = 0,
-        LastToken = 120,
+        LastToken = 121,
         FirstTriviaToken = 2,
         LastTriviaToken = 6,
         FirstLiteralToken = 7,
@@ -291,7 +292,7 @@ declare module "typescript" {
         LastTemplateToken = 13,
         FirstBinaryOperator = 24,
         LastBinaryOperator = 63,
-        FirstNode = 121,
+        FirstNode = 122,
     }
     const enum NodeFlags {
         Export = 1,
@@ -1031,8 +1032,9 @@ declare module "typescript" {
         ObjectLiteral = 131072,
         ContainsUndefinedOrNull = 262144,
         ContainsObjectLiteral = 524288,
-        Intrinsic = 127,
-        Primitive = 510,
+        ESSymbol = 1048576,
+        Intrinsic = 1048703,
+        Primitive = 1049086,
         StringLike = 258,
         NumberLike = 132,
         ObjectType = 48128,

tests/baselines/reference/APISample_compile.types

@@ -553,274 +553,277 @@ declare module "typescript" {
         StringKeyword = 119,
 >StringKeyword : SyntaxKind
 
-        TypeKeyword = 120,
+        SymbolKeyword = 120,
+>SymbolKeyword : SyntaxKind
+
+        TypeKeyword = 121,
 >TypeKeyword : SyntaxKind
 
-        QualifiedName = 121,
+        QualifiedName = 122,
 >QualifiedName : SyntaxKind
 
-        ComputedPropertyName = 122,
+        ComputedPropertyName = 123,
 >ComputedPropertyName : SyntaxKind
 
-        TypeParameter = 123,
+        TypeParameter = 124,
 >TypeParameter : SyntaxKind
 
-        Parameter = 124,
+        Parameter = 125,
 >Parameter : SyntaxKind
 
-        PropertySignature = 125,
+        PropertySignature = 126,
 >PropertySignature : SyntaxKind
 
-        PropertyDeclaration = 126,
+        PropertyDeclaration = 127,
 >PropertyDeclaration : SyntaxKind
 
-        MethodSignature = 127,
+        MethodSignature = 128,
 >MethodSignature : SyntaxKind
 
-        MethodDeclaration = 128,
+        MethodDeclaration = 129,
 >MethodDeclaration : SyntaxKind
 
-        Constructor = 129,
+        Constructor = 130,
 >Constructor : SyntaxKind
 
-        GetAccessor = 130,
+        GetAccessor = 131,
 >GetAccessor : SyntaxKind
 
-        SetAccessor = 131,
+        SetAccessor = 132,
 >SetAccessor : SyntaxKind
 
-        CallSignature = 132,
+        CallSignature = 133,
 >CallSignature : SyntaxKind
 
-        ConstructSignature = 133,
+        ConstructSignature = 134,
 >ConstructSignature : SyntaxKind
 
-        IndexSignature = 134,
+        IndexSignature = 135,
 >IndexSignature : SyntaxKind
 
-        TypeReference = 135,
+        TypeReference = 136,
 >TypeReference : SyntaxKind
 
-        FunctionType = 136,
+        FunctionType = 137,
 >FunctionType : SyntaxKind
 
-        ConstructorType = 137,
+        ConstructorType = 138,
 >ConstructorType : SyntaxKind
 
-        TypeQuery = 138,
+        TypeQuery = 139,
 >TypeQuery : SyntaxKind
 
-        TypeLiteral = 139,
+        TypeLiteral = 140,
 >TypeLiteral : SyntaxKind
 
-        ArrayType = 140,
+        ArrayType = 141,
 >ArrayType : SyntaxKind
 
-        TupleType = 141,
+        TupleType = 142,
 >TupleType : SyntaxKind
 
-        UnionType = 142,
+        UnionType = 143,
 >UnionType : SyntaxKind
 
-        ParenthesizedType = 143,
+        ParenthesizedType = 144,
 >ParenthesizedType : SyntaxKind
 
-        ObjectBindingPattern = 144,
+        ObjectBindingPattern = 145,
 >ObjectBindingPattern : SyntaxKind
 
-        ArrayBindingPattern = 145,
+        ArrayBindingPattern = 146,
 >ArrayBindingPattern : SyntaxKind
 
-        BindingElement = 146,
+        BindingElement = 147,
 >BindingElement : SyntaxKind
 
-        ArrayLiteralExpression = 147,
+        ArrayLiteralExpression = 148,
 >ArrayLiteralExpression : SyntaxKind
 
-        ObjectLiteralExpression = 148,
+        ObjectLiteralExpression = 149,
 >ObjectLiteralExpression : SyntaxKind
 
-        PropertyAccessExpression = 149,
+        PropertyAccessExpression = 150,
 >PropertyAccessExpression : SyntaxKind
 
-        ElementAccessExpression = 150,
+        ElementAccessExpression = 151,
 >ElementAccessExpression : SyntaxKind
 
-        CallExpression = 151,
+        CallExpression = 152,
 >CallExpression : SyntaxKind
 
-        NewExpression = 152,
+        NewExpression = 153,
 >NewExpression : SyntaxKind
 
-        TaggedTemplateExpression = 153,
+        TaggedTemplateExpression = 154,
 >TaggedTemplateExpression : SyntaxKind
 
-        TypeAssertionExpression = 154,
+        TypeAssertionExpression = 155,
 >TypeAssertionExpression : SyntaxKind
 
-        ParenthesizedExpression = 155,
+        ParenthesizedExpression = 156,
 >ParenthesizedExpression : SyntaxKind
 
-        FunctionExpression = 156,
+        FunctionExpression = 157,
 >FunctionExpression : SyntaxKind
 
-        ArrowFunction = 157,
+        ArrowFunction = 158,
 >ArrowFunction : SyntaxKind
 
-        DeleteExpression = 158,
+        DeleteExpression = 159,
 >DeleteExpression : SyntaxKind
 
-        TypeOfExpression = 159,
+        TypeOfExpression = 160,
 >TypeOfExpression : SyntaxKind
 
-        VoidExpression = 160,
+        VoidExpression = 161,
 >VoidExpression : SyntaxKind
 
-        PrefixUnaryExpression = 161,
+        PrefixUnaryExpression = 162,
 >PrefixUnaryExpression : SyntaxKind
 
-        PostfixUnaryExpression = 162,
+        PostfixUnaryExpression = 163,
 >PostfixUnaryExpression : SyntaxKind
 
-        BinaryExpression = 163,
+        BinaryExpression = 164,
 >BinaryExpression : SyntaxKind
 
-        ConditionalExpression = 164,
+        ConditionalExpression = 165,
 >ConditionalExpression : SyntaxKind
 
-        TemplateExpression = 165,
+        TemplateExpression = 166,
 >TemplateExpression : SyntaxKind
 
-        YieldExpression = 166,
+        YieldExpression = 167,
 >YieldExpression : SyntaxKind
 
-        SpreadElementExpression = 167,
+        SpreadElementExpression = 168,
 >SpreadElementExpression : SyntaxKind
 
-        OmittedExpression = 168,
+        OmittedExpression = 169,
 >OmittedExpression : SyntaxKind
 
-        TemplateSpan = 169,
+        TemplateSpan = 170,
 >TemplateSpan : SyntaxKind
 
-        Block = 170,
+        Block = 171,
 >Block : SyntaxKind
 
-        VariableStatement = 171,
+        VariableStatement = 172,
 >VariableStatement : SyntaxKind
 
-        EmptyStatement = 172,
+        EmptyStatement = 173,
 >EmptyStatement : SyntaxKind
 
-        ExpressionStatement = 173,
+        ExpressionStatement = 174,
 >ExpressionStatement : SyntaxKind
 
-        IfStatement = 174,
+        IfStatement = 175,
 >IfStatement : SyntaxKind
 
-        DoStatement = 175,
+        DoStatement = 176,
 >DoStatement : SyntaxKind
 
-        WhileStatement = 176,
+        WhileStatement = 177,
 >WhileStatement : SyntaxKind
 
-        ForStatement = 177,
+        ForStatement = 178,
 >ForStatement : SyntaxKind
 
-        ForInStatement = 178,
+        ForInStatement = 179,
 >ForInStatement : SyntaxKind
 
-        ContinueStatement = 179,
+        ContinueStatement = 180,
 >ContinueStatement : SyntaxKind
 
-        BreakStatement = 180,
+        BreakStatement = 181,
 >BreakStatement : SyntaxKind
 
-        ReturnStatement = 181,
+        ReturnStatement = 182,
 >ReturnStatement : SyntaxKind
 
-        WithStatement = 182,
+        WithStatement = 183,
 >WithStatement : SyntaxKind
 
-        SwitchStatement = 183,
+        SwitchStatement = 184,
 >SwitchStatement : SyntaxKind
 
-        LabeledStatement = 184,
+        LabeledStatement = 185,
 >LabeledStatement : SyntaxKind
 
-        ThrowStatement = 185,
+        ThrowStatement = 186,
 >ThrowStatement : SyntaxKind
 
-        TryStatement = 186,
+        TryStatement = 187,
 >TryStatement : SyntaxKind
 
-        DebuggerStatement = 187,
+        DebuggerStatement = 188,
 >DebuggerStatement : SyntaxKind
 
-        VariableDeclaration = 188,
+        VariableDeclaration = 189,
 >VariableDeclaration : SyntaxKind
 
-        VariableDeclarationList = 189,
+        VariableDeclarationList = 190,
 >VariableDeclarationList : SyntaxKind
 
-        FunctionDeclaration = 190,
+        FunctionDeclaration = 191,
 >FunctionDeclaration : SyntaxKind
 
-        ClassDeclaration = 191,
+        ClassDeclaration = 192,
 >ClassDeclaration : SyntaxKind
 
-        InterfaceDeclaration = 192,
+        InterfaceDeclaration = 193,
 >InterfaceDeclaration : SyntaxKind
 
-        TypeAliasDeclaration = 193,
+        TypeAliasDeclaration = 194,
 >TypeAliasDeclaration : SyntaxKind
 
-        EnumDeclaration = 194,
+        EnumDeclaration = 195,
 >EnumDeclaration : SyntaxKind
 
-        ModuleDeclaration = 195,
+        ModuleDeclaration = 196,
 >ModuleDeclaration : SyntaxKind
 
-        ModuleBlock = 196,
+        ModuleBlock = 197,
 >ModuleBlock : SyntaxKind
 
-        ImportDeclaration = 197,
+        ImportDeclaration = 198,
 >ImportDeclaration : SyntaxKind
 
-        ExportAssignment = 198,
+        ExportAssignment = 199,
 >ExportAssignment : SyntaxKind
 
-        ExternalModuleReference = 199,
+        ExternalModuleReference = 200,
 >ExternalModuleReference : SyntaxKind
 
-        CaseClause = 200,
+        CaseClause = 201,
 >CaseClause : SyntaxKind
 
-        DefaultClause = 201,
+        DefaultClause = 202,
 >DefaultClause : SyntaxKind
 
-        HeritageClause = 202,
+        HeritageClause = 203,
 >HeritageClause : SyntaxKind
 
-        CatchClause = 203,
+        CatchClause = 204,
 >CatchClause : SyntaxKind
 
-        PropertyAssignment = 204,
+        PropertyAssignment = 205,
 >PropertyAssignment : SyntaxKind
 
-        ShorthandPropertyAssignment = 205,
+        ShorthandPropertyAssignment = 206,
 >ShorthandPropertyAssignment : SyntaxKind
 
-        EnumMember = 206,
+        EnumMember = 207,
 >EnumMember : SyntaxKind
 
-        SourceFile = 207,
+        SourceFile = 208,
 >SourceFile : SyntaxKind
 
-        SyntaxList = 208,
+        SyntaxList = 209,
 >SyntaxList : SyntaxKind
 
-        Count = 209,
+        Count = 210,
 >Count : SyntaxKind
 
         FirstAssignment = 52,
@@ -838,7 +841,7 @@ declare module "typescript" {
         FirstKeyword = 65,
 >FirstKeyword : SyntaxKind
 
-        LastKeyword = 120,
+        LastKeyword = 121,
 >LastKeyword : SyntaxKind
 
         FirstFutureReservedWord = 101,
@@ -847,10 +850,10 @@ declare module "typescript" {
         LastFutureReservedWord = 109,
 >LastFutureReservedWord : SyntaxKind
 
-        FirstTypeNode = 135,
+        FirstTypeNode = 136,
 >FirstTypeNode : SyntaxKind
 
-        LastTypeNode = 143,
+        LastTypeNode = 144,
 >LastTypeNode : SyntaxKind
 
         FirstPunctuation = 14,
@@ -862,7 +865,7 @@ declare module "typescript" {
         FirstToken = 0,
 >FirstToken : SyntaxKind
 
-        LastToken = 120,
+        LastToken = 121,
 >LastToken : SyntaxKind
 
         FirstTriviaToken = 2,
@@ -889,7 +892,7 @@ declare module "typescript" {
         LastBinaryOperator = 63,
 >LastBinaryOperator : SyntaxKind
 
-        FirstNode = 121,
+        FirstNode = 122,
 >FirstNode : SyntaxKind
     }
     const enum NodeFlags {
@@ -3318,10 +3321,13 @@ declare module "typescript" {
         ContainsObjectLiteral = 524288,
 >ContainsObjectLiteral : TypeFlags
 
-        Intrinsic = 127,
+        ESSymbol = 1048576,
+>ESSymbol : TypeFlags
+
+        Intrinsic = 1048703,
 >Intrinsic : TypeFlags
 
-        Primitive = 510,
+        Primitive = 1049086,
 >Primitive : TypeFlags
 
         StringLike = 258,

tests/baselines/reference/APISample_linter.js

@@ -210,110 +210,111 @@ declare module "typescript" {
         NumberKeyword = 117,
         SetKeyword = 118,
         StringKeyword = 119,
-        TypeKeyword = 120,
-        QualifiedName = 121,
-        ComputedPropertyName = 122,
-        TypeParameter = 123,
-        Parameter = 124,
-        PropertySignature = 125,
-        PropertyDeclaration = 126,
-        MethodSignature = 127,
-        MethodDeclaration = 128,
-        Constructor = 129,
-        GetAccessor = 130,
-        SetAccessor = 131,
-        CallSignature = 132,
-        ConstructSignature = 133,
-        IndexSignature = 134,
-        TypeReference = 135,
-        FunctionType = 136,
-        ConstructorType = 137,
-        TypeQuery = 138,
-        TypeLiteral = 139,
-        ArrayType = 140,
-        TupleType = 141,
-        UnionType = 142,
-        ParenthesizedType = 143,
-        ObjectBindingPattern = 144,
-        ArrayBindingPattern = 145,
-        BindingElement = 146,
-        ArrayLiteralExpression = 147,
-        ObjectLiteralExpression = 148,
-        PropertyAccessExpression = 149,
-        ElementAccessExpression = 150,
-        CallExpression = 151,
-        NewExpression = 152,
-        TaggedTemplateExpression = 153,
-        TypeAssertionExpression = 154,
-        ParenthesizedExpression = 155,
-        FunctionExpression = 156,
-        ArrowFunction = 157,
-        DeleteExpression = 158,
-        TypeOfExpression = 159,
-        VoidExpression = 160,
-        PrefixUnaryExpression = 161,
-        PostfixUnaryExpression = 162,
-        BinaryExpression = 163,
-        ConditionalExpression = 164,
-        TemplateExpression = 165,
-        YieldExpression = 166,
-        SpreadElementExpression = 167,
-        OmittedExpression = 168,
-        TemplateSpan = 169,
-        Block = 170,
-        VariableStatement = 171,
-        EmptyStatement = 172,
-        ExpressionStatement = 173,
-        IfStatement = 174,
-        DoStatement = 175,
-        WhileStatement = 176,
-        ForStatement = 177,
-        ForInStatement = 178,
-        ContinueStatement = 179,
-        BreakStatement = 180,
-        ReturnStatement = 181,
-        WithStatement = 182,
-        SwitchStatement = 183,
-        LabeledStatement = 184,
-        ThrowStatement = 185,
-        TryStatement = 186,
-        DebuggerStatement = 187,
-        VariableDeclaration = 188,
-        VariableDeclarationList = 189,
-        FunctionDeclaration = 190,
-        ClassDeclaration = 191,
-        InterfaceDeclaration = 192,
-        TypeAliasDeclaration = 193,
-        EnumDeclaration = 194,
-        ModuleDeclaration = 195,
-        ModuleBlock = 196,
-        ImportDeclaration = 197,
-        ExportAssignment = 198,
-        ExternalModuleReference = 199,
-        CaseClause = 200,
-        DefaultClause = 201,
-        HeritageClause = 202,
-        CatchClause = 203,
-        PropertyAssignment = 204,
-        ShorthandPropertyAssignment = 205,
-        EnumMember = 206,
-        SourceFile = 207,
-        SyntaxList = 208,
-        Count = 209,
+        SymbolKeyword = 120,
+        TypeKeyword = 121,
+        QualifiedName = 122,
+        ComputedPropertyName = 123,
+        TypeParameter = 124,
+        Parameter = 125,
+        PropertySignature = 126,
+        PropertyDeclaration = 127,
+        MethodSignature = 128,
+        MethodDeclaration = 129,
+        Constructor = 130,
+        GetAccessor = 131,
+        SetAccessor = 132,
+        CallSignature = 133,
+        ConstructSignature = 134,
+        IndexSignature = 135,
+        TypeReference = 136,
+        FunctionType = 137,
+        ConstructorType = 138,
+        TypeQuery = 139,
+        TypeLiteral = 140,
+        ArrayType = 141,
+        TupleType = 142,
+        UnionType = 143,
+        ParenthesizedType = 144,
+        ObjectBindingPattern = 145,
+        ArrayBindingPattern = 146,
+        BindingElement = 147,
+        ArrayLiteralExpression = 148,
+        ObjectLiteralExpression = 149,
+        PropertyAccessExpression = 150,
+        ElementAccessExpression = 151,
+        CallExpression = 152,
+        NewExpression = 153,
+        TaggedTemplateExpression = 154,
+        TypeAssertionExpression = 155,
+        ParenthesizedExpression = 156,
+        FunctionExpression = 157,
+        ArrowFunction = 158,
+        DeleteExpression = 159,
+        TypeOfExpression = 160,
+        VoidExpression = 161,
+        PrefixUnaryExpression = 162,
+        PostfixUnaryExpression = 163,
+        BinaryExpression = 164,
+        ConditionalExpression = 165,
+        TemplateExpression = 166,
+        YieldExpression = 167,
+        SpreadElementExpression = 168,
+        OmittedExpression = 169,
+        TemplateSpan = 170,
+        Block = 171,
+        VariableStatement = 172,
+        EmptyStatement = 173,
+        ExpressionStatement = 174,
+        IfStatement = 175,
+        DoStatement = 176,
+        WhileStatement = 177,
+        ForStatement = 178,
+        ForInStatement = 179,
+        ContinueStatement = 180,
+        BreakStatement = 181,
+        ReturnStatement = 182,
+        WithStatement = 183,
+        SwitchStatement = 184,
+        LabeledStatement = 185,
+        ThrowStatement = 186,
+        TryStatement = 187,
+        DebuggerStatement = 188,
+        VariableDeclaration = 189,
+        VariableDeclarationList = 190,
+        FunctionDeclaration = 191,
+        ClassDeclaration = 192,
+        InterfaceDeclaration = 193,
+        TypeAliasDeclaration = 194,
+        EnumDeclaration = 195,
+        ModuleDeclaration = 196,
+        ModuleBlock = 197,
+        ImportDeclaration = 198,
+        ExportAssignment = 199,
+        ExternalModuleReference = 200,
+        CaseClause = 201,
+        DefaultClause = 202,
+        HeritageClause = 203,
+        CatchClause = 204,
+        PropertyAssignment = 205,
+        ShorthandPropertyAssignment = 206,
+        EnumMember = 207,
+        SourceFile = 208,
+        SyntaxList = 209,
+        Count = 210,
         FirstAssignment = 52,
         LastAssignment = 63,
         FirstReservedWord = 65,
         LastReservedWord = 100,
         FirstKeyword = 65,
-        LastKeyword = 120,
+        LastKeyword = 121,
         FirstFutureReservedWord = 101,
         LastFutureReservedWord = 109,
-        FirstTypeNode = 135,
-        LastTypeNode = 143,
+        FirstTypeNode = 136,
+        LastTypeNode = 144,
         FirstPunctuation = 14,
         LastPunctuation = 63,
         FirstToken = 0,
-        LastToken = 120,
+        LastToken = 121,
         FirstTriviaToken = 2,
         LastTriviaToken = 6,
         FirstLiteralToken = 7,
@@ -322,7 +323,7 @@ declare module "typescript" {
         LastTemplateToken = 13,
         FirstBinaryOperator = 24,
         LastBinaryOperator = 63,
-        FirstNode = 121,
+        FirstNode = 122,
     }
     const enum NodeFlags {
         Export = 1,
@@ -1062,8 +1063,9 @@ declare module "typescript" {
         ObjectLiteral = 131072,
         ContainsUndefinedOrNull = 262144,
         ContainsObjectLiteral = 524288,
-        Intrinsic = 127,
-        Primitive = 510,
+        ESSymbol = 1048576,
+        Intrinsic = 1048703,
+        Primitive = 1049086,
         StringLike = 258,
         NumberLike = 132,
         ObjectType = 48128,
@@ -1976,24 +1978,24 @@ function delint(sourceFile) {
     delintNode(sourceFile);
     function delintNode(node) {
         switch (node.kind) {
-            case 177 /* ForStatement */:
-            case 178 /* ForInStatement */:
-            case 176 /* WhileStatement */:
-            case 175 /* DoStatement */:
-                if (node.statement.kind !== 170 /* Block */) {
+            case 178 /* ForStatement */:
+            case 179 /* ForInStatement */:
+            case 177 /* WhileStatement */:
+            case 176 /* DoStatement */:
+                if (node.statement.kind !== 171 /* Block */) {
                     report(node, "A looping statement's contents should be wrapped in a block body.");
                 }
                 break;
-            case 174 /* IfStatement */:
+            case 175 /* IfStatement */:
                 var ifStatement = node;
-                if (ifStatement.thenStatement.kind !== 170 /* Block */) {
+                if (ifStatement.thenStatement.kind !== 171 /* Block */) {
                     report(ifStatement.thenStatement, "An if statement's contents should be wrapped in a block body.");
                 }
-                if (ifStatement.elseStatement && ifStatement.elseStatement.kind !== 170 /* Block */ && ifStatement.elseStatement.kind !== 174 /* IfStatement */) {
+                if (ifStatement.elseStatement && ifStatement.elseStatement.kind !== 171 /* Block */ && ifStatement.elseStatement.kind !== 175 /* IfStatement */) {
                     report(ifStatement.elseStatement, "An else statement's contents should be wrapped in a block body.");
                 }
                 break;
-            case 163 /* BinaryExpression */:
+            case 164 /* BinaryExpression */:
                 var op = node.operator;
                 if (op === 28 /* EqualsEqualsToken */ || op === 29 /* ExclamationEqualsToken */) {
                     report(node, "Use '===' and '!=='.");

tests/baselines/reference/APISample_linter.types

@@ -697,274 +697,277 @@ declare module "typescript" {
         StringKeyword = 119,
 >StringKeyword : SyntaxKind
 
-        TypeKeyword = 120,
+        SymbolKeyword = 120,
+>SymbolKeyword : SyntaxKind
+
+        TypeKeyword = 121,
 >TypeKeyword : SyntaxKind
 
-        QualifiedName = 121,
+        QualifiedName = 122,
 >QualifiedName : SyntaxKind
 
-        ComputedPropertyName = 122,
+        ComputedPropertyName = 123,
 >ComputedPropertyName : SyntaxKind
 
-        TypeParameter = 123,
+        TypeParameter = 124,
 >TypeParameter : SyntaxKind
 
-        Parameter = 124,
+        Parameter = 125,
 >Parameter : SyntaxKind
 
-        PropertySignature = 125,
+        PropertySignature = 126,
 >PropertySignature : SyntaxKind
 
-        PropertyDeclaration = 126,
+        PropertyDeclaration = 127,
 >PropertyDeclaration : SyntaxKind
 
-        MethodSignature = 127,
+        MethodSignature = 128,
 >MethodSignature : SyntaxKind
 
-        MethodDeclaration = 128,
+        MethodDeclaration = 129,
 >MethodDeclaration : SyntaxKind
 
-        Constructor = 129,
+        Constructor = 130,
 >Constructor : SyntaxKind
 
-        GetAccessor = 130,
+        GetAccessor = 131,
 >GetAccessor : SyntaxKind
 
-        SetAccessor = 131,
+        SetAccessor = 132,
 >SetAccessor : SyntaxKind
 
-        CallSignature = 132,
+        CallSignature = 133,
 >CallSignature : SyntaxKind
 
-        ConstructSignature = 133,
+        ConstructSignature = 134,
 >ConstructSignature : SyntaxKind
 
-        IndexSignature = 134,
+        IndexSignature = 135,
 >IndexSignature : SyntaxKind
 
-        TypeReference = 135,
+        TypeReference = 136,
 >TypeReference : SyntaxKind
 
-        FunctionType = 136,
+        FunctionType = 137,
 >FunctionType : SyntaxKind
 
-        ConstructorType = 137,
+        ConstructorType = 138,
 >ConstructorType : SyntaxKind
 
-        TypeQuery = 138,
+        TypeQuery = 139,
 >TypeQuery : SyntaxKind
 
-        TypeLiteral = 139,
+        TypeLiteral = 140,
 >TypeLiteral : SyntaxKind
 
-        ArrayType = 140,
+        ArrayType = 141,
 >ArrayType : SyntaxKind
 
-        TupleType = 141,
+        TupleType = 142,
 >TupleType : SyntaxKind
 
-        UnionType = 142,
+        UnionType = 143,
 >UnionType : SyntaxKind
 
-        ParenthesizedType = 143,
+        ParenthesizedType = 144,
 >ParenthesizedType : SyntaxKind
 
-        ObjectBindingPattern = 144,
+        ObjectBindingPattern = 145,
 >ObjectBindingPattern : SyntaxKind
 
-        ArrayBindingPattern = 145,
+        ArrayBindingPattern = 146,
 >ArrayBindingPattern : SyntaxKind
 
-        BindingElement = 146,
+        BindingElement = 147,
 >BindingElement : SyntaxKind
 
-        ArrayLiteralExpression = 147,
+        ArrayLiteralExpression = 148,
 >ArrayLiteralExpression : SyntaxKind
 
-        ObjectLiteralExpression = 148,
+        ObjectLiteralExpression = 149,
 >ObjectLiteralExpression : SyntaxKind
 
-        PropertyAccessExpression = 149,
+        PropertyAccessExpression = 150,
 >PropertyAccessExpression : SyntaxKind
 
-        ElementAccessExpression = 150,
+        ElementAccessExpression = 151,
 >ElementAccessExpression : SyntaxKind
 
-        CallExpression = 151,
+        CallExpression = 152,
 >CallExpression : SyntaxKind
 
-        NewExpression = 152,
+        NewExpression = 153,
 >NewExpression : SyntaxKind
 
-        TaggedTemplateExpression = 153,
+        TaggedTemplateExpression = 154,
 >TaggedTemplateExpression : SyntaxKind
 
-        TypeAssertionExpression = 154,
+        TypeAssertionExpression = 155,
 >TypeAssertionExpression : SyntaxKind
 
-        ParenthesizedExpression = 155,
+        ParenthesizedExpression = 156,
 >ParenthesizedExpression : SyntaxKind
 
-        FunctionExpression = 156,
+        FunctionExpression = 157,
 >FunctionExpression : SyntaxKind
 
-        ArrowFunction = 157,
+        ArrowFunction = 158,
 >ArrowFunction : SyntaxKind
 
-        DeleteExpression = 158,
+        DeleteExpression = 159,
 >DeleteExpression : SyntaxKind
 
-        TypeOfExpression = 159,
+        TypeOfExpression = 160,
 >TypeOfExpression : SyntaxKind
 
-        VoidExpression = 160,
+        VoidExpression = 161,
 >VoidExpression : SyntaxKind
 
-        PrefixUnaryExpression = 161,
+        PrefixUnaryExpression = 162,
 >PrefixUnaryExpression : SyntaxKind
 
-        PostfixUnaryExpression = 162,
+        PostfixUnaryExpression = 163,
 >PostfixUnaryExpression : SyntaxKind
 
-        BinaryExpression = 163,
+        BinaryExpression = 164,
 >BinaryExpression : SyntaxKind
 
-        ConditionalExpression = 164,
+        ConditionalExpression = 165,
 >ConditionalExpression : SyntaxKind
 
-        TemplateExpression = 165,
+        TemplateExpression = 166,
 >TemplateExpression : SyntaxKind
 
-        YieldExpression = 166,
+        YieldExpression = 167,
 >YieldExpression : SyntaxKind
 
-        SpreadElementExpression = 167,
+        SpreadElementExpression = 168,
 >SpreadElementExpression : SyntaxKind
 
-        OmittedExpression = 168,
+        OmittedExpression = 169,
 >OmittedExpression : SyntaxKind
 
-        TemplateSpan = 169,
+        TemplateSpan = 170,
 >TemplateSpan : SyntaxKind
 
-        Block = 170,
+        Block = 171,
 >Block : SyntaxKind
 
-        VariableStatement = 171,
+        VariableStatement = 172,
 >VariableStatement : SyntaxKind
 
-        EmptyStatement = 172,
+        EmptyStatement = 173,
 >EmptyStatement : SyntaxKind
 
-        ExpressionStatement = 173,
+        ExpressionStatement = 174,
 >ExpressionStatement : SyntaxKind
 
-        IfStatement = 174,
+        IfStatement = 175,
 >IfStatement : SyntaxKind
 
-        DoStatement = 175,
+        DoStatement = 176,
 >DoStatement : SyntaxKind
 
-        WhileStatement = 176,
+        WhileStatement = 177,
 >WhileStatement : SyntaxKind
 
-        ForStatement = 177,
+        ForStatement = 178,
 >ForStatement : SyntaxKind
 
-        ForInStatement = 178,
+        ForInStatement = 179,
 >ForInStatement : SyntaxKind
 
-        ContinueStatement = 179,
+        ContinueStatement = 180,
 >ContinueStatement : SyntaxKind
 
-        BreakStatement = 180,
+        BreakStatement = 181,
 >BreakStatement : SyntaxKind
 
-        ReturnStatement = 181,
+        ReturnStatement = 182,
 >ReturnStatement : SyntaxKind
 
-        WithStatement = 182,
+        WithStatement = 183,
 >WithStatement : SyntaxKind
 
-        SwitchStatement = 183,
+        SwitchStatement = 184,
 >SwitchStatement : SyntaxKind
 
-        LabeledStatement = 184,
+        LabeledStatement = 185,
 >LabeledStatement : SyntaxKind
 
-        ThrowStatement = 185,
+        ThrowStatement = 186,
 >ThrowStatement : SyntaxKind
 
-        TryStatement = 186,
+        TryStatement = 187,
 >TryStatement : SyntaxKind
 
-        DebuggerStatement = 187,
+        DebuggerStatement = 188,
 >DebuggerStatement : SyntaxKind
 
-        VariableDeclaration = 188,
+        VariableDeclaration = 189,
 >VariableDeclaration : SyntaxKind
 
-        VariableDeclarationList = 189,
+        VariableDeclarationList = 190,
 >VariableDeclarationList : SyntaxKind
 
-        FunctionDeclaration = 190,
+        FunctionDeclaration = 191,
 >FunctionDeclaration : SyntaxKind
 
-        ClassDeclaration = 191,
+        ClassDeclaration = 192,
 >ClassDeclaration : SyntaxKind
 
-        InterfaceDeclaration = 192,
+        InterfaceDeclaration = 193,
 >InterfaceDeclaration : SyntaxKind
 
-        TypeAliasDeclaration = 193,
+        TypeAliasDeclaration = 194,
 >TypeAliasDeclaration : SyntaxKind
 
-        EnumDeclaration = 194,
+        EnumDeclaration = 195,
 >EnumDeclaration : SyntaxKind
 
-        ModuleDeclaration = 195,
+        ModuleDeclaration = 196,
 >ModuleDeclaration : SyntaxKind
 
-        ModuleBlock = 196,
+        ModuleBlock = 197,
 >ModuleBlock : SyntaxKind
 
-        ImportDeclaration = 197,
+        ImportDeclaration = 198,
 >ImportDeclaration : SyntaxKind
 
-        ExportAssignment = 198,
+        ExportAssignment = 199,
 >ExportAssignment : SyntaxKind
 
-        ExternalModuleReference = 199,
+        ExternalModuleReference = 200,
 >ExternalModuleReference : SyntaxKind
 
-        CaseClause = 200,
+        CaseClause = 201,
 >CaseClause : SyntaxKind
 
-        DefaultClause = 201,
+        DefaultClause = 202,
 >DefaultClause : SyntaxKind
 
-        HeritageClause = 202,
+        HeritageClause = 203,
 >HeritageClause : SyntaxKind
 
-        CatchClause = 203,
+        CatchClause = 204,
 >CatchClause : SyntaxKind
 
-        PropertyAssignment = 204,
+        PropertyAssignment = 205,
 >PropertyAssignment : SyntaxKind
 
-        ShorthandPropertyAssignment = 205,
+        ShorthandPropertyAssignment = 206,
 >ShorthandPropertyAssignment : SyntaxKind
 
-        EnumMember = 206,
+        EnumMember = 207,
 >EnumMember : SyntaxKind
 
-        SourceFile = 207,
+        SourceFile = 208,
 >SourceFile : SyntaxKind
 
-        SyntaxList = 208,
+        SyntaxList = 209,
 >SyntaxList : SyntaxKind
 
-        Count = 209,
+        Count = 210,
 >Count : SyntaxKind
 
         FirstAssignment = 52,
@@ -982,7 +985,7 @@ declare module "typescript" {
         FirstKeyword = 65,
 >FirstKeyword : SyntaxKind
 
-        LastKeyword = 120,
+        LastKeyword = 121,
 >LastKeyword : SyntaxKind
 
         FirstFutureReservedWord = 101,
@@ -991,10 +994,10 @@ declare module "typescript" {
         LastFutureReservedWord = 109,
 >LastFutureReservedWord : SyntaxKind
 
-        FirstTypeNode = 135,
+        FirstTypeNode = 136,
 >FirstTypeNode : SyntaxKind
 
-        LastTypeNode = 143,
+        LastTypeNode = 144,
 >LastTypeNode : SyntaxKind
 
         FirstPunctuation = 14,
@@ -1006,7 +1009,7 @@ declare module "typescript" {
         FirstToken = 0,
 >FirstToken : SyntaxKind
 
-        LastToken = 120,
+        LastToken = 121,
 >LastToken : SyntaxKind
 
         FirstTriviaToken = 2,
@@ -1033,7 +1036,7 @@ declare module "typescript" {
         LastBinaryOperator = 63,
 >LastBinaryOperator : SyntaxKind
 
-        FirstNode = 121,
+        FirstNode = 122,
 >FirstNode : SyntaxKind
     }
     const enum NodeFlags {
@@ -3462,10 +3465,13 @@ declare module "typescript" {
         ContainsObjectLiteral = 524288,
 >ContainsObjectLiteral : TypeFlags
 
-        Intrinsic = 127,
+        ESSymbol = 1048576,
+>ESSymbol : TypeFlags
+
+        Intrinsic = 1048703,
 >Intrinsic : TypeFlags
 
-        Primitive = 510,
+        Primitive = 1049086,
 >Primitive : TypeFlags
 
         StringLike = 258,

tests/baselines/reference/APISample_transform.js

@@ -211,110 +211,111 @@ declare module "typescript" {
         NumberKeyword = 117,
         SetKeyword = 118,
         StringKeyword = 119,
-        TypeKeyword = 120,
-        QualifiedName = 121,
-        ComputedPropertyName = 122,
-        TypeParameter = 123,
-        Parameter = 124,
-        PropertySignature = 125,
-        PropertyDeclaration = 126,
-        MethodSignature = 127,
-        MethodDeclaration = 128,
-        Constructor = 129,
-        GetAccessor = 130,
-        SetAccessor = 131,
-        CallSignature = 132,
-        ConstructSignature = 133,
-        IndexSignature = 134,
-        TypeReference = 135,
-        FunctionType = 136,
-        ConstructorType = 137,
-        TypeQuery = 138,
-        TypeLiteral = 139,
-        ArrayType = 140,
-        TupleType = 141,
-        UnionType = 142,
-        ParenthesizedType = 143,
-        ObjectBindingPattern = 144,
-        ArrayBindingPattern = 145,
-        BindingElement = 146,
-        ArrayLiteralExpression = 147,
-        ObjectLiteralExpression = 148,
-        PropertyAccessExpression = 149,
-        ElementAccessExpression = 150,
-        CallExpression = 151,
-        NewExpression = 152,
-        TaggedTemplateExpression = 153,
-        TypeAssertionExpression = 154,
-        ParenthesizedExpression = 155,
-        FunctionExpression = 156,
-        ArrowFunction = 157,
-        DeleteExpression = 158,
-        TypeOfExpression = 159,
-        VoidExpression = 160,
-        PrefixUnaryExpression = 161,
-        PostfixUnaryExpression = 162,
-        BinaryExpression = 163,
-        ConditionalExpression = 164,
-        TemplateExpression = 165,
-        YieldExpression = 166,
-        SpreadElementExpression = 167,
-        OmittedExpression = 168,
-        TemplateSpan = 169,
-        Block = 170,
-        VariableStatement = 171,
-        EmptyStatement = 172,
-        ExpressionStatement = 173,
-        IfStatement = 174,
-        DoStatement = 175,
-        WhileStatement = 176,
-        ForStatement = 177,
-        ForInStatement = 178,
-        ContinueStatement = 179,
-        BreakStatement = 180,
-        ReturnStatement = 181,
-        WithStatement = 182,
-        SwitchStatement = 183,
-        LabeledStatement = 184,
-        ThrowStatement = 185,
-        TryStatement = 186,
-        DebuggerStatement = 187,
-        VariableDeclaration = 188,
-        VariableDeclarationList = 189,
-        FunctionDeclaration = 190,
-        ClassDeclaration = 191,
-        InterfaceDeclaration = 192,
-        TypeAliasDeclaration = 193,
-        EnumDeclaration = 194,
-        ModuleDeclaration = 195,
-        ModuleBlock = 196,
-        ImportDeclaration = 197,
-        ExportAssignment = 198,
-        ExternalModuleReference = 199,
-        CaseClause = 200,
-        DefaultClause = 201,
-        HeritageClause = 202,
-        CatchClause = 203,
-        PropertyAssignment = 204,
-        ShorthandPropertyAssignment = 205,
-        EnumMember = 206,
-        SourceFile = 207,
-        SyntaxList = 208,
-        Count = 209,
+        SymbolKeyword = 120,
+        TypeKeyword = 121,
+        QualifiedName = 122,
+        ComputedPropertyName = 123,
+        TypeParameter = 124,
+        Parameter = 125,
+        PropertySignature = 126,
+        PropertyDeclaration = 127,
+        MethodSignature = 128,
+        MethodDeclaration = 129,
+        Constructor = 130,
+        GetAccessor = 131,
+        SetAccessor = 132,
+        CallSignature = 133,
+        ConstructSignature = 134,
+        IndexSignature = 135,
+        TypeReference = 136,
+        FunctionType = 137,
+        ConstructorType = 138,
+        TypeQuery = 139,
+        TypeLiteral = 140,
+        ArrayType = 141,
+        TupleType = 142,
+        UnionType = 143,
+        ParenthesizedType = 144,
+        ObjectBindingPattern = 145,
+        ArrayBindingPattern = 146,
+        BindingElement = 147,
+        ArrayLiteralExpression = 148,
+        ObjectLiteralExpression = 149,
+        PropertyAccessExpression = 150,
+        ElementAccessExpression = 151,
+        CallExpression = 152,
+        NewExpression = 153,
+        TaggedTemplateExpression = 154,
+        TypeAssertionExpression = 155,
+        ParenthesizedExpression = 156,
+        FunctionExpression = 157,
+        ArrowFunction = 158,
+        DeleteExpression = 159,
+        TypeOfExpression = 160,
+        VoidExpression = 161,
+        PrefixUnaryExpression = 162,
+        PostfixUnaryExpression = 163,
+        BinaryExpression = 164,
+        ConditionalExpression = 165,
+        TemplateExpression = 166,
+        YieldExpression = 167,
+        SpreadElementExpression = 168,
+        OmittedExpression = 169,
+        TemplateSpan = 170,
+        Block = 171,
+        VariableStatement = 172,
+        EmptyStatement = 173,
+        ExpressionStatement = 174,
+        IfStatement = 175,
+        DoStatement = 176,
+        WhileStatement = 177,
+        ForStatement = 178,
+        ForInStatement = 179,
+        ContinueStatement = 180,
+        BreakStatement = 181,
+        ReturnStatement = 182,
+        WithStatement = 183,
+        SwitchStatement = 184,
+        LabeledStatement = 185,
+        ThrowStatement = 186,
+        TryStatement = 187,
+        DebuggerStatement = 188,
+        VariableDeclaration = 189,
+        VariableDeclarationList = 190,
+        FunctionDeclaration = 191,
+        ClassDeclaration = 192,
+        InterfaceDeclaration = 193,
+        TypeAliasDeclaration = 194,
+        EnumDeclaration = 195,
+        ModuleDeclaration = 196,
+        ModuleBlock = 197,
+        ImportDeclaration = 198,
+        ExportAssignment = 199,
+        ExternalModuleReference = 200,
+        CaseClause = 201,
+        DefaultClause = 202,
+        HeritageClause = 203,
+        CatchClause = 204,
+        PropertyAssignment = 205,
+        ShorthandPropertyAssignment = 206,
+        EnumMember = 207,
+        SourceFile = 208,
+        SyntaxList = 209,
+        Count = 210,
         FirstAssignment = 52,
         LastAssignment = 63,
         FirstReservedWord = 65,
         LastReservedWord = 100,
         FirstKeyword = 65,
-        LastKeyword = 120,
+        LastKeyword = 121,
         FirstFutureReservedWord = 101,
         LastFutureReservedWord = 109,
-        FirstTypeNode = 135,
-        LastTypeNode = 143,
+        FirstTypeNode = 136,
+        LastTypeNode = 144,
         FirstPunctuation = 14,
         LastPunctuation = 63,
         FirstToken = 0,
-        LastToken = 120,
+        LastToken = 121,
         FirstTriviaToken = 2,
         LastTriviaToken = 6,
         FirstLiteralToken = 7,
@@ -323,7 +324,7 @@ declare module "typescript" {
         LastTemplateToken = 13,
         FirstBinaryOperator = 24,
         LastBinaryOperator = 63,
-        FirstNode = 121,
+        FirstNode = 122,
     }
     const enum NodeFlags {
         Export = 1,
@@ -1063,8 +1064,9 @@ declare module "typescript" {
         ObjectLiteral = 131072,
         ContainsUndefinedOrNull = 262144,
         ContainsObjectLiteral = 524288,
-        Intrinsic = 127,
-        Primitive = 510,
+        ESSymbol = 1048576,
+        Intrinsic = 1048703,
+        Primitive = 1049086,
         StringLike = 258,
         NumberLike = 132,
         ObjectType = 48128,

tests/baselines/reference/APISample_transform.types

@@ -649,274 +649,277 @@ declare module "typescript" {
         StringKeyword = 119,
 >StringKeyword : SyntaxKind
 
-        TypeKeyword = 120,
+        SymbolKeyword = 120,
+>SymbolKeyword : SyntaxKind
+
+        TypeKeyword = 121,
 >TypeKeyword : SyntaxKind
 
-        QualifiedName = 121,
+        QualifiedName = 122,
 >QualifiedName : SyntaxKind
 
-        ComputedPropertyName = 122,
+        ComputedPropertyName = 123,
 >ComputedPropertyName : SyntaxKind
 
-        TypeParameter = 123,
+        TypeParameter = 124,
 >TypeParameter : SyntaxKind
 
-        Parameter = 124,
+        Parameter = 125,
 >Parameter : SyntaxKind
 
-        PropertySignature = 125,
+        PropertySignature = 126,
 >PropertySignature : SyntaxKind
 
-        PropertyDeclaration = 126,
+        PropertyDeclaration = 127,
 >PropertyDeclaration : SyntaxKind
 
-        MethodSignature = 127,
+        MethodSignature = 128,
 >MethodSignature : SyntaxKind
 
-        MethodDeclaration = 128,
+        MethodDeclaration = 129,
 >MethodDeclaration : SyntaxKind
 
-        Constructor = 129,
+        Constructor = 130,
 >Constructor : SyntaxKind
 
-        GetAccessor = 130,
+        GetAccessor = 131,
 >GetAccessor : SyntaxKind
 
-        SetAccessor = 131,
+        SetAccessor = 132,
 >SetAccessor : SyntaxKind
 
-        CallSignature = 132,
+        CallSignature = 133,
 >CallSignature : SyntaxKind
 
-        ConstructSignature = 133,
+        ConstructSignature = 134,
 >ConstructSignature : SyntaxKind
 
-        IndexSignature = 134,
+        IndexSignature = 135,
 >IndexSignature : SyntaxKind
 
-        TypeReference = 135,
+        TypeReference = 136,
 >TypeReference : SyntaxKind
 
-        FunctionType = 136,
+        FunctionType = 137,
 >FunctionType : SyntaxKind
 
-        ConstructorType = 137,
+        ConstructorType = 138,
 >ConstructorType : SyntaxKind
 
-        TypeQuery = 138,
+        TypeQuery = 139,
 >TypeQuery : SyntaxKind
 
-        TypeLiteral = 139,
+        TypeLiteral = 140,
 >TypeLiteral : SyntaxKind
 
-        ArrayType = 140,
+        ArrayType = 141,
 >ArrayType : SyntaxKind
 
-        TupleType = 141,
+        TupleType = 142,
 >TupleType : SyntaxKind
 
-        UnionType = 142,
+        UnionType = 143,
 >UnionType : SyntaxKind
 
-        ParenthesizedType = 143,
+        ParenthesizedType = 144,
 >ParenthesizedType : SyntaxKind
 
-        ObjectBindingPattern = 144,
+        ObjectBindingPattern = 145,
 >ObjectBindingPattern : SyntaxKind
 
-        ArrayBindingPattern = 145,
+        ArrayBindingPattern = 146,
 >ArrayBindingPattern : SyntaxKind
 
-        BindingElement = 146,
+        BindingElement = 147,
 >BindingElement : SyntaxKind
 
-        ArrayLiteralExpression = 147,
+        ArrayLiteralExpression = 148,
 >ArrayLiteralExpression : SyntaxKind
 
-        ObjectLiteralExpression = 148,
+        ObjectLiteralExpression = 149,
 >ObjectLiteralExpression : SyntaxKind
 
-        PropertyAccessExpression = 149,
+        PropertyAccessExpression = 150,
 >PropertyAccessExpression : SyntaxKind
 
-        ElementAccessExpression = 150,
+        ElementAccessExpression = 151,
 >ElementAccessExpression : SyntaxKind
 
-        CallExpression = 151,
+        CallExpression = 152,
 >CallExpression : SyntaxKind
 
-        NewExpression = 152,
+        NewExpression = 153,
 >NewExpression : SyntaxKind
 
-        TaggedTemplateExpression = 153,
+        TaggedTemplateExpression = 154,
 >TaggedTemplateExpression : SyntaxKind
 
-        TypeAssertionExpression = 154,
+        TypeAssertionExpression = 155,
 >TypeAssertionExpression : SyntaxKind
 
-        ParenthesizedExpression = 155,
+        ParenthesizedExpression = 156,
 >ParenthesizedExpression : SyntaxKind
 
-        FunctionExpression = 156,
+        FunctionExpression = 157,
 >FunctionExpression : SyntaxKind
 
-        ArrowFunction = 157,
+        ArrowFunction = 158,
 >ArrowFunction : SyntaxKind
 
-        DeleteExpression = 158,
+        DeleteExpression = 159,
 >DeleteExpression : SyntaxKind
 
-        TypeOfExpression = 159,
+        TypeOfExpression = 160,
 >TypeOfExpression : SyntaxKind
 
-        VoidExpression = 160,
+        VoidExpression = 161,
 >VoidExpression : SyntaxKind
 
-        PrefixUnaryExpression = 161,
+        PrefixUnaryExpression = 162,
 >PrefixUnaryExpression : SyntaxKind
 
-        PostfixUnaryExpression = 162,
+        PostfixUnaryExpression = 163,
 >PostfixUnaryExpression : SyntaxKind
 
-        BinaryExpression = 163,
+        BinaryExpression = 164,
 >BinaryExpression : SyntaxKind
 
-        ConditionalExpression = 164,
+        ConditionalExpression = 165,
 >ConditionalExpression : SyntaxKind
 
-        TemplateExpression = 165,
+        TemplateExpression = 166,
 >TemplateExpression : SyntaxKind
 
-        YieldExpression = 166,
+        YieldExpression = 167,
 >YieldExpression : SyntaxKind
 
-        SpreadElementExpression = 167,
+        SpreadElementExpression = 168,
 >SpreadElementExpression : SyntaxKind
 
-        OmittedExpression = 168,
+        OmittedExpression = 169,
 >OmittedExpression : SyntaxKind
 
-        TemplateSpan = 169,
+        TemplateSpan = 170,
 >TemplateSpan : SyntaxKind
 
-        Block = 170,
+        Block = 171,
 >Block : SyntaxKind
 
-        VariableStatement = 171,
+        VariableStatement = 172,
 >VariableStatement : SyntaxKind
 
-        EmptyStatement = 172,
+        EmptyStatement = 173,
 >EmptyStatement : SyntaxKind
 
-        ExpressionStatement = 173,
+        ExpressionStatement = 174,
 >ExpressionStatement : SyntaxKind
 
-        IfStatement = 174,
+        IfStatement = 175,
 >IfStatement : SyntaxKind
 
-        DoStatement = 175,
+        DoStatement = 176,
 >DoStatement : SyntaxKind
 
-        WhileStatement = 176,
+        WhileStatement = 177,
 >WhileStatement : SyntaxKind
 
-        ForStatement = 177,
+        ForStatement = 178,
 >ForStatement : SyntaxKind
 
-        ForInStatement = 178,
+        ForInStatement = 179,
 >ForInStatement : SyntaxKind
 
-        ContinueStatement = 179,
+        ContinueStatement = 180,
 >ContinueStatement : SyntaxKind
 
-        BreakStatement = 180,
+        BreakStatement = 181,
 >BreakStatement : SyntaxKind
 
-        ReturnStatement = 181,
+        ReturnStatement = 182,
 >ReturnStatement : SyntaxKind
 
-        WithStatement = 182,
+        WithStatement = 183,
 >WithStatement : SyntaxKind
 
-        SwitchStatement = 183,
+        SwitchStatement = 184,
 >SwitchStatement : SyntaxKind
 
-        LabeledStatement = 184,
+        LabeledStatement = 185,
 >LabeledStatement : SyntaxKind
 
-        ThrowStatement = 185,
+        ThrowStatement = 186,
 >ThrowStatement : SyntaxKind
 
-        TryStatement = 186,
+        TryStatement = 187,
 >TryStatement : SyntaxKind
 
-        DebuggerStatement = 187,
+        DebuggerStatement = 188,
 >DebuggerStatement : SyntaxKind
 
-        VariableDeclaration = 188,
+        VariableDeclaration = 189,
 >VariableDeclaration : SyntaxKind
 
-        VariableDeclarationList = 189,
+        VariableDeclarationList = 190,
 >VariableDeclarationList : SyntaxKind
 
-        FunctionDeclaration = 190,
+        FunctionDeclaration = 191,
 >FunctionDeclaration : SyntaxKind
 
-        ClassDeclaration = 191,
+        ClassDeclaration = 192,
 >ClassDeclaration : SyntaxKind
 
-        InterfaceDeclaration = 192,
+        InterfaceDeclaration = 193,
 >InterfaceDeclaration : SyntaxKind
 
-        TypeAliasDeclaration = 193,
+        TypeAliasDeclaration = 194,
 >TypeAliasDeclaration : SyntaxKind
 
-        EnumDeclaration = 194,
+        EnumDeclaration = 195,
 >EnumDeclaration : SyntaxKind
 
-        ModuleDeclaration = 195,
+        ModuleDeclaration = 196,
 >ModuleDeclaration : SyntaxKind
 
-        ModuleBlock = 196,
+        ModuleBlock = 197,
 >ModuleBlock : SyntaxKind
 
-        ImportDeclaration = 197,
+        ImportDeclaration = 198,
 >ImportDeclaration : SyntaxKind
 
-        ExportAssignment = 198,
+        ExportAssignment = 199,
 >ExportAssignment : SyntaxKind
 
-        ExternalModuleReference = 199,
+        ExternalModuleReference = 200,
 >ExternalModuleReference : SyntaxKind
 
-        CaseClause = 200,
+        CaseClause = 201,
 >CaseClause : SyntaxKind
 
-        DefaultClause = 201,
+        DefaultClause = 202,
 >DefaultClause : SyntaxKind
 
-        HeritageClause = 202,
+        HeritageClause = 203,
 >HeritageClause : SyntaxKind
 
-        CatchClause = 203,
+        CatchClause = 204,
 >CatchClause : SyntaxKind
 
-        PropertyAssignment = 204,
+        PropertyAssignment = 205,
 >PropertyAssignment : SyntaxKind
 
-        ShorthandPropertyAssignment = 205,
+        ShorthandPropertyAssignment = 206,
 >ShorthandPropertyAssignment : SyntaxKind
 
-        EnumMember = 206,
+        EnumMember = 207,
 >EnumMember : SyntaxKind
 
-        SourceFile = 207,
+        SourceFile = 208,
 >SourceFile : SyntaxKind
 
-        SyntaxList = 208,
+        SyntaxList = 209,
 >SyntaxList : SyntaxKind
 
-        Count = 209,
+        Count = 210,
 >Count : SyntaxKind
 
         FirstAssignment = 52,
@@ -934,7 +937,7 @@ declare module "typescript" {
         FirstKeyword = 65,
 >FirstKeyword : SyntaxKind
 
-        LastKeyword = 120,
+        LastKeyword = 121,
 >LastKeyword : SyntaxKind
 
         FirstFutureReservedWord = 101,
@@ -943,10 +946,10 @@ declare module "typescript" {
         LastFutureReservedWord = 109,
 >LastFutureReservedWord : SyntaxKind
 
-        FirstTypeNode = 135,
+        FirstTypeNode = 136,
 >FirstTypeNode : SyntaxKind
 
-        LastTypeNode = 143,
+        LastTypeNode = 144,
 >LastTypeNode : SyntaxKind
 
         FirstPunctuation = 14,
@@ -958,7 +961,7 @@ declare module "typescript" {
         FirstToken = 0,
 >FirstToken : SyntaxKind
 
-        LastToken = 120,
+        LastToken = 121,
 >LastToken : SyntaxKind
 
         FirstTriviaToken = 2,
@@ -985,7 +988,7 @@ declare module "typescript" {
         LastBinaryOperator = 63,
 >LastBinaryOperator : SyntaxKind
 
-        FirstNode = 121,
+        FirstNode = 122,
 >FirstNode : SyntaxKind
     }
     const enum NodeFlags {
@@ -3414,10 +3417,13 @@ declare module "typescript" {
         ContainsObjectLiteral = 524288,
 >ContainsObjectLiteral : TypeFlags
 
-        Intrinsic = 127,
+        ESSymbol = 1048576,
+>ESSymbol : TypeFlags
+
+        Intrinsic = 1048703,
 >Intrinsic : TypeFlags
 
-        Primitive = 510,
+        Primitive = 1049086,
 >Primitive : TypeFlags
 
         StringLike = 258,

tests/baselines/reference/APISample_watcher.js

@@ -248,110 +248,111 @@ declare module "typescript" {
         NumberKeyword = 117,
         SetKeyword = 118,
         StringKeyword = 119,
-        TypeKeyword = 120,
-        QualifiedName = 121,
-        ComputedPropertyName = 122,
-        TypeParameter = 123,
-        Parameter = 124,
-        PropertySignature = 125,
-        PropertyDeclaration = 126,
-        MethodSignature = 127,
-        MethodDeclaration = 128,
-        Constructor = 129,
-        GetAccessor = 130,
-        SetAccessor = 131,
-        CallSignature = 132,
-        ConstructSignature = 133,
-        IndexSignature = 134,
-        TypeReference = 135,
-        FunctionType = 136,
-        ConstructorType = 137,
-        TypeQuery = 138,
-        TypeLiteral = 139,
-        ArrayType = 140,
-        TupleType = 141,
-        UnionType = 142,
-        ParenthesizedType = 143,
-        ObjectBindingPattern = 144,
-        ArrayBindingPattern = 145,
-        BindingElement = 146,
-        ArrayLiteralExpression = 147,
-        ObjectLiteralExpression = 148,
-        PropertyAccessExpression = 149,
-        ElementAccessExpression = 150,
-        CallExpression = 151,
-        NewExpression = 152,
-        TaggedTemplateExpression = 153,
-        TypeAssertionExpression = 154,
-        ParenthesizedExpression = 155,
-        FunctionExpression = 156,
-        ArrowFunction = 157,
-        DeleteExpression = 158,
-        TypeOfExpression = 159,
-        VoidExpression = 160,
-        PrefixUnaryExpression = 161,
-        PostfixUnaryExpression = 162,
-        BinaryExpression = 163,
-        ConditionalExpression = 164,
-        TemplateExpression = 165,
-        YieldExpression = 166,
-        SpreadElementExpression = 167,
-        OmittedExpression = 168,
-        TemplateSpan = 169,
-        Block = 170,
-        VariableStatement = 171,
-        EmptyStatement = 172,
-        ExpressionStatement = 173,
-        IfStatement = 174,
-        DoStatement = 175,
-        WhileStatement = 176,
-        ForStatement = 177,
-        ForInStatement = 178,
-        ContinueStatement = 179,
-        BreakStatement = 180,
-        ReturnStatement = 181,
-        WithStatement = 182,
-        SwitchStatement = 183,
-        LabeledStatement = 184,
-        ThrowStatement = 185,
-        TryStatement = 186,
-        DebuggerStatement = 187,
-        VariableDeclaration = 188,
-        VariableDeclarationList = 189,
-        FunctionDeclaration = 190,
-        ClassDeclaration = 191,
-        InterfaceDeclaration = 192,
-        TypeAliasDeclaration = 193,
-        EnumDeclaration = 194,
-        ModuleDeclaration = 195,
-        ModuleBlock = 196,
-        ImportDeclaration = 197,
-        ExportAssignment = 198,
-        ExternalModuleReference = 199,
-        CaseClause = 200,
-        DefaultClause = 201,
-        HeritageClause = 202,
-        CatchClause = 203,
-        PropertyAssignment = 204,
-        ShorthandPropertyAssignment = 205,
-        EnumMember = 206,
-        SourceFile = 207,
-        SyntaxList = 208,
-        Count = 209,
+        SymbolKeyword = 120,
+        TypeKeyword = 121,
+        QualifiedName = 122,
+        ComputedPropertyName = 123,
+        TypeParameter = 124,
+        Parameter = 125,
+        PropertySignature = 126,
+        PropertyDeclaration = 127,
+        MethodSignature = 128,
+        MethodDeclaration = 129,
+        Constructor = 130,
+        GetAccessor = 131,
+        SetAccessor = 132,
+        CallSignature = 133,
+        ConstructSignature = 134,
+        IndexSignature = 135,
+        TypeReference = 136,
+        FunctionType = 137,
+        ConstructorType = 138,
+        TypeQuery = 139,
+        TypeLiteral = 140,
+        ArrayType = 141,
+        TupleType = 142,
+        UnionType = 143,
+        ParenthesizedType = 144,
+        ObjectBindingPattern = 145,
+        ArrayBindingPattern = 146,
+        BindingElement = 147,
+        ArrayLiteralExpression = 148,
+        ObjectLiteralExpression = 149,
+        PropertyAccessExpression = 150,
+        ElementAccessExpression = 151,
+        CallExpression = 152,
+        NewExpression = 153,
+        TaggedTemplateExpression = 154,
+        TypeAssertionExpression = 155,
+        ParenthesizedExpression = 156,
+        FunctionExpression = 157,
+        ArrowFunction = 158,
+        DeleteExpression = 159,
+        TypeOfExpression = 160,
+        VoidExpression = 161,
+        PrefixUnaryExpression = 162,
+        PostfixUnaryExpression = 163,
+        BinaryExpression = 164,
+        ConditionalExpression = 165,
+        TemplateExpression = 166,
+        YieldExpression = 167,
+        SpreadElementExpression = 168,
+        OmittedExpression = 169,
+        TemplateSpan = 170,
+        Block = 171,
+        VariableStatement = 172,
+        EmptyStatement = 173,
+        ExpressionStatement = 174,
+        IfStatement = 175,
+        DoStatement = 176,
+        WhileStatement = 177,
+        ForStatement = 178,
+        ForInStatement = 179,
+        ContinueStatement = 180,
+        BreakStatement = 181,
+        ReturnStatement = 182,
+        WithStatement = 183,
+        SwitchStatement = 184,
+        LabeledStatement = 185,
+        ThrowStatement = 186,
+        TryStatement = 187,
+        DebuggerStatement = 188,
+        VariableDeclaration = 189,
+        VariableDeclarationList = 190,
+        FunctionDeclaration = 191,
+        ClassDeclaration = 192,
+        InterfaceDeclaration = 193,
+        TypeAliasDeclaration = 194,
+        EnumDeclaration = 195,
+        ModuleDeclaration = 196,
+        ModuleBlock = 197,
+        ImportDeclaration = 198,
+        ExportAssignment = 199,
+        ExternalModuleReference = 200,
+        CaseClause = 201,
+        DefaultClause = 202,
+        HeritageClause = 203,
+        CatchClause = 204,
+        PropertyAssignment = 205,
+        ShorthandPropertyAssignment = 206,
+        EnumMember = 207,
+        SourceFile = 208,
+        SyntaxList = 209,
+        Count = 210,
         FirstAssignment = 52,
         LastAssignment = 63,
         FirstReservedWord = 65,
         LastReservedWord = 100,
         FirstKeyword = 65,
-        LastKeyword = 120,
+        LastKeyword = 121,
         FirstFutureReservedWord = 101,
         LastFutureReservedWord = 109,
-        FirstTypeNode = 135,
-        LastTypeNode = 143,
+        FirstTypeNode = 136,
+        LastTypeNode = 144,
         FirstPunctuation = 14,
         LastPunctuation = 63,
         FirstToken = 0,
-        LastToken = 120,
+        LastToken = 121,
         FirstTriviaToken = 2,
         LastTriviaToken = 6,
         FirstLiteralToken = 7,
@@ -360,7 +361,7 @@ declare module "typescript" {
         LastTemplateToken = 13,
         FirstBinaryOperator = 24,
         LastBinaryOperator = 63,
-        FirstNode = 121,
+        FirstNode = 122,
     }
     const enum NodeFlags {
         Export = 1,
@@ -1100,8 +1101,9 @@ declare module "typescript" {
         ObjectLiteral = 131072,
         ContainsUndefinedOrNull = 262144,
         ContainsObjectLiteral = 524288,
-        Intrinsic = 127,
-        Primitive = 510,
+        ESSymbol = 1048576,
+        Intrinsic = 1048703,
+        Primitive = 1049086,
         StringLike = 258,
         NumberLike = 132,
         ObjectType = 48128,

tests/baselines/reference/APISample_watcher.types

@@ -822,274 +822,277 @@ declare module "typescript" {
         StringKeyword = 119,
 >StringKeyword : SyntaxKind
 
-        TypeKeyword = 120,
+        SymbolKeyword = 120,
+>SymbolKeyword : SyntaxKind
+
+        TypeKeyword = 121,
 >TypeKeyword : SyntaxKind
 
-        QualifiedName = 121,
+        QualifiedName = 122,
 >QualifiedName : SyntaxKind
 
-        ComputedPropertyName = 122,
+        ComputedPropertyName = 123,
 >ComputedPropertyName : SyntaxKind
 
-        TypeParameter = 123,
+        TypeParameter = 124,
 >TypeParameter : SyntaxKind
 
-        Parameter = 124,
+        Parameter = 125,
 >Parameter : SyntaxKind
 
-        PropertySignature = 125,
+        PropertySignature = 126,
 >PropertySignature : SyntaxKind
 
-        PropertyDeclaration = 126,
+        PropertyDeclaration = 127,
 >PropertyDeclaration : SyntaxKind
 
-        MethodSignature = 127,
+        MethodSignature = 128,
 >MethodSignature : SyntaxKind
 
-        MethodDeclaration = 128,
+        MethodDeclaration = 129,
 >MethodDeclaration : SyntaxKind
 
-        Constructor = 129,
+        Constructor = 130,
 >Constructor : SyntaxKind
 
-        GetAccessor = 130,
+        GetAccessor = 131,
 >GetAccessor : SyntaxKind
 
-        SetAccessor = 131,
+        SetAccessor = 132,
 >SetAccessor : SyntaxKind
 
-        CallSignature = 132,
+        CallSignature = 133,
 >CallSignature : SyntaxKind
 
-        ConstructSignature = 133,
+        ConstructSignature = 134,
 >ConstructSignature : SyntaxKind
 
-        IndexSignature = 134,
+        IndexSignature = 135,
 >IndexSignature : SyntaxKind
 
-        TypeReference = 135,
+        TypeReference = 136,
 >TypeReference : SyntaxKind
 
-        FunctionType = 136,
+        FunctionType = 137,
 >FunctionType : SyntaxKind
 
-        ConstructorType = 137,
+        ConstructorType = 138,
 >ConstructorType : SyntaxKind
 
-        TypeQuery = 138,
+        TypeQuery = 139,
 >TypeQuery : SyntaxKind
 
-        TypeLiteral = 139,
+        TypeLiteral = 140,
 >TypeLiteral : SyntaxKind
 
-        ArrayType = 140,
+        ArrayType = 141,
 >ArrayType : SyntaxKind
 
-        TupleType = 141,
+        TupleType = 142,
 >TupleType : SyntaxKind
 
-        UnionType = 142,
+        UnionType = 143,
 >UnionType : SyntaxKind
 
-        ParenthesizedType = 143,
+        ParenthesizedType = 144,
 >ParenthesizedType : SyntaxKind
 
-        ObjectBindingPattern = 144,
+        ObjectBindingPattern = 145,
 >ObjectBindingPattern : SyntaxKind
 
-        ArrayBindingPattern = 145,
+        ArrayBindingPattern = 146,
 >ArrayBindingPattern : SyntaxKind
 
-        BindingElement = 146,
+        BindingElement = 147,
 >BindingElement : SyntaxKind
 
-        ArrayLiteralExpression = 147,
+        ArrayLiteralExpression = 148,
 >ArrayLiteralExpression : SyntaxKind
 
-        ObjectLiteralExpression = 148,
+        ObjectLiteralExpression = 149,
 >ObjectLiteralExpression : SyntaxKind
 
-        PropertyAccessExpression = 149,
+        PropertyAccessExpression = 150,
 >PropertyAccessExpression : SyntaxKind
 
-        ElementAccessExpression = 150,
+        ElementAccessExpression = 151,
 >ElementAccessExpression : SyntaxKind
 
-        CallExpression = 151,
+        CallExpression = 152,
 >CallExpression : SyntaxKind
 
-        NewExpression = 152,
+        NewExpression = 153,
 >NewExpression : SyntaxKind
 
-        TaggedTemplateExpression = 153,
+        TaggedTemplateExpression = 154,
 >TaggedTemplateExpression : SyntaxKind
 
-        TypeAssertionExpression = 154,
+        TypeAssertionExpression = 155,
 >TypeAssertionExpression : SyntaxKind
 
-        ParenthesizedExpression = 155,
+        ParenthesizedExpression = 156,
 >ParenthesizedExpression : SyntaxKind
 
-        FunctionExpression = 156,
+        FunctionExpression = 157,
 >FunctionExpression : SyntaxKind
 
-        ArrowFunction = 157,
+        ArrowFunction = 158,
 >ArrowFunction : SyntaxKind
 
-        DeleteExpression = 158,
+        DeleteExpression = 159,
 >DeleteExpression : SyntaxKind
 
-        TypeOfExpression = 159,
+        TypeOfExpression = 160,
 >TypeOfExpression : SyntaxKind
 
-        VoidExpression = 160,
+        VoidExpression = 161,
 >VoidExpression : SyntaxKind
 
-        PrefixUnaryExpression = 161,
+        PrefixUnaryExpression = 162,
 >PrefixUnaryExpression : SyntaxKind
 
-        PostfixUnaryExpression = 162,
+        PostfixUnaryExpression = 163,
 >PostfixUnaryExpression : SyntaxKind
 
-        BinaryExpression = 163,
+        BinaryExpression = 164,
 >BinaryExpression : SyntaxKind
 
-        ConditionalExpression = 164,
+        ConditionalExpression = 165,
 >ConditionalExpression : SyntaxKind
 
-        TemplateExpression = 165,
+        TemplateExpression = 166,
 >TemplateExpression : SyntaxKind
 
-        YieldExpression = 166,
+        YieldExpression = 167,
 >YieldExpression : SyntaxKind
 
-        SpreadElementExpression = 167,
+        SpreadElementExpression = 168,
 >SpreadElementExpression : SyntaxKind
 
-        OmittedExpression = 168,
+        OmittedExpression = 169,
 >OmittedExpression : SyntaxKind
 
-        TemplateSpan = 169,
+        TemplateSpan = 170,
 >TemplateSpan : SyntaxKind
 
-        Block = 170,
+        Block = 171,
 >Block : SyntaxKind
 
-        VariableStatement = 171,
+        VariableStatement = 172,
 >VariableStatement : SyntaxKind
 
-        EmptyStatement = 172,
+        EmptyStatement = 173,
 >EmptyStatement : SyntaxKind
 
-        ExpressionStatement = 173,
+        ExpressionStatement = 174,
 >ExpressionStatement : SyntaxKind
 
-        IfStatement = 174,
+        IfStatement = 175,
 >IfStatement : SyntaxKind
 
-        DoStatement = 175,
+        DoStatement = 176,
 >DoStatement : SyntaxKind
 
-        WhileStatement = 176,
+        WhileStatement = 177,
 >WhileStatement : SyntaxKind
 
-        ForStatement = 177,
+        ForStatement = 178,
 >ForStatement : SyntaxKind
 
-        ForInStatement = 178,
+        ForInStatement = 179,
 >ForInStatement : SyntaxKind
 
-        ContinueStatement = 179,
+        ContinueStatement = 180,
 >ContinueStatement : SyntaxKind
 
-        BreakStatement = 180,
+        BreakStatement = 181,
 >BreakStatement : SyntaxKind
 
-        ReturnStatement = 181,
+        ReturnStatement = 182,
 >ReturnStatement : SyntaxKind
 
-        WithStatement = 182,
+        WithStatement = 183,
 >WithStatement : SyntaxKind
 
-        SwitchStatement = 183,
+        SwitchStatement = 184,
 >SwitchStatement : SyntaxKind
 
-        LabeledStatement = 184,
+        LabeledStatement = 185,
 >LabeledStatement : SyntaxKind
 
-        ThrowStatement = 185,
+        ThrowStatement = 186,
 >ThrowStatement : SyntaxKind
 
-        TryStatement = 186,
+        TryStatement = 187,
 >TryStatement : SyntaxKind
 
-        DebuggerStatement = 187,
+        DebuggerStatement = 188,
 >DebuggerStatement : SyntaxKind
 
-        VariableDeclaration = 188,
+        VariableDeclaration = 189,
 >VariableDeclaration : SyntaxKind
 
-        VariableDeclarationList = 189,
+        VariableDeclarationList = 190,
 >VariableDeclarationList : SyntaxKind
 
-        FunctionDeclaration = 190,
+        FunctionDeclaration = 191,
 >FunctionDeclaration : SyntaxKind
 
-        ClassDeclaration = 191,
+        ClassDeclaration = 192,
 >ClassDeclaration : SyntaxKind
 
-        InterfaceDeclaration = 192,
+        InterfaceDeclaration = 193,
 >InterfaceDeclaration : SyntaxKind
 
-        TypeAliasDeclaration = 193,
+        TypeAliasDeclaration = 194,
 >TypeAliasDeclaration : SyntaxKind
 
-        EnumDeclaration = 194,
+        EnumDeclaration = 195,
 >EnumDeclaration : SyntaxKind
 
-        ModuleDeclaration = 195,
+        ModuleDeclaration = 196,
 >ModuleDeclaration : SyntaxKind
 
-        ModuleBlock = 196,
+        ModuleBlock = 197,
 >ModuleBlock : SyntaxKind
 
-        ImportDeclaration = 197,
+        ImportDeclaration = 198,
 >ImportDeclaration : SyntaxKind
 
-        ExportAssignment = 198,
+        ExportAssignment = 199,
 >ExportAssignment : SyntaxKind
 
-        ExternalModuleReference = 199,
+        ExternalModuleReference = 200,
 >ExternalModuleReference : SyntaxKind
 
-        CaseClause = 200,
+        CaseClause = 201,
 >CaseClause : SyntaxKind
 
-        DefaultClause = 201,
+        DefaultClause = 202,
 >DefaultClause : SyntaxKind
 
-        HeritageClause = 202,
+        HeritageClause = 203,
 >HeritageClause : SyntaxKind
 
-        CatchClause = 203,
+        CatchClause = 204,
 >CatchClause : SyntaxKind
 
-        PropertyAssignment = 204,
+        PropertyAssignment = 205,
 >PropertyAssignment : SyntaxKind
 
-        ShorthandPropertyAssignment = 205,
+        ShorthandPropertyAssignment = 206,
 >ShorthandPropertyAssignment : SyntaxKind
 
-        EnumMember = 206,
+        EnumMember = 207,
 >EnumMember : SyntaxKind
 
-        SourceFile = 207,
+        SourceFile = 208,
 >SourceFile : SyntaxKind
 
-        SyntaxList = 208,
+        SyntaxList = 209,
 >SyntaxList : SyntaxKind
 
-        Count = 209,
+        Count = 210,
 >Count : SyntaxKind
 
         FirstAssignment = 52,
@@ -1107,7 +1110,7 @@ declare module "typescript" {
         FirstKeyword = 65,
 >FirstKeyword : SyntaxKind
 
-        LastKeyword = 120,
+        LastKeyword = 121,
 >LastKeyword : SyntaxKind
 
         FirstFutureReservedWord = 101,
@@ -1116,10 +1119,10 @@ declare module "typescript" {
         LastFutureReservedWord = 109,
 >LastFutureReservedWord : SyntaxKind
 
-        FirstTypeNode = 135,
+        FirstTypeNode = 136,
 >FirstTypeNode : SyntaxKind
 
-        LastTypeNode = 143,
+        LastTypeNode = 144,
 >LastTypeNode : SyntaxKind
 
         FirstPunctuation = 14,
@@ -1131,7 +1134,7 @@ declare module "typescript" {
         FirstToken = 0,
 >FirstToken : SyntaxKind
 
-        LastToken = 120,
+        LastToken = 121,
 >LastToken : SyntaxKind
 
         FirstTriviaToken = 2,
@@ -1158,7 +1161,7 @@ declare module "typescript" {
         LastBinaryOperator = 63,
 >LastBinaryOperator : SyntaxKind
 
-        FirstNode = 121,
+        FirstNode = 122,
 >FirstNode : SyntaxKind
     }
     const enum NodeFlags {
@@ -3587,10 +3590,13 @@ declare module "typescript" {
         ContainsObjectLiteral = 524288,
 >ContainsObjectLiteral : TypeFlags
 
-        Intrinsic = 127,
+        ESSymbol = 1048576,
+>ESSymbol : TypeFlags
+
+        Intrinsic = 1048703,
 >Intrinsic : TypeFlags
 
-        Primitive = 510,
+        Primitive = 1049086,
 >Primitive : TypeFlags
 
         StringLike = 258,

tests/baselines/reference/ES5SymbolProperty1.errors.txt

@@ -0,0 +1,19 @@
+tests/cases/conformance/Symbols/ES5SymbolProperty1.ts(7,5): error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+tests/cases/conformance/Symbols/ES5SymbolProperty1.ts(7,6): error TS2471: A computed property name of the form 'Symbol.foo' must be of type 'symbol'.
+
+
+==== tests/cases/conformance/Symbols/ES5SymbolProperty1.ts (2 errors) ====
+    interface SymbolConstructor {
+        foo: string;
+    }
+    var Symbol: SymbolConstructor;
+    
+    var obj = {
+        [Symbol.foo]: 0
+        ~~~~~~~~~~~~
+!!! error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+         ~~~~~~~~~~
+!!! error TS2471: A computed property name of the form 'Symbol.foo' must be of type 'symbol'.
+    }
+    
+    obj[Symbol.foo];

tests/baselines/reference/ES5SymbolProperty1.js

@@ -0,0 +1,18 @@
+//// [ES5SymbolProperty1.ts]
+interface SymbolConstructor {
+    foo: string;
+}
+var Symbol: SymbolConstructor;
+
+var obj = {
+    [Symbol.foo]: 0
+}
+
+obj[Symbol.foo];
+
+//// [ES5SymbolProperty1.js]
+var Symbol;
+var obj = {
+    [Symbol.foo]: 0
+};
+obj[Symbol.foo];

tests/baselines/reference/ES5SymbolProperty2.errors.txt

@@ -0,0 +1,22 @@
+tests/cases/conformance/Symbols/ES5SymbolProperty2.ts(5,9): error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+tests/cases/conformance/Symbols/ES5SymbolProperty2.ts(5,10): error TS2471: A computed property name of the form 'Symbol.iterator' must be of type 'symbol'.
+tests/cases/conformance/Symbols/ES5SymbolProperty2.ts(10,11): error TS2304: Cannot find name 'Symbol'.
+
+
+==== tests/cases/conformance/Symbols/ES5SymbolProperty2.ts (3 errors) ====
+    module M {
+        var Symbol;
+    
+        export class C {
+            [Symbol.iterator]() { }
+            ~~~~~~~~~~~~~~~~~
+!!! error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+             ~~~~~~~~~~~~~~~
+!!! error TS2471: A computed property name of the form 'Symbol.iterator' must be of type 'symbol'.
+        }
+        (new C)[Symbol.iterator];
+    }
+    
+    (new M.C)[Symbol.iterator];
+              ~~~~~~
+!!! error TS2304: Cannot find name 'Symbol'.

tests/baselines/reference/ES5SymbolProperty2.js

@@ -0,0 +1,26 @@
+//// [ES5SymbolProperty2.ts]
+module M {
+    var Symbol;
+
+    export class C {
+        [Symbol.iterator]() { }
+    }
+    (new C)[Symbol.iterator];
+}
+
+(new M.C)[Symbol.iterator];
+
+//// [ES5SymbolProperty2.js]
+var M;
+(function (M) {
+    var Symbol;
+    var C = (function () {
+        function C() {
+        }
+        C.prototype[Symbol.iterator] = function () { };
+        return C;
+    })();
+    M.C = C;
+    (new C)[Symbol.iterator];
+})(M || (M = {}));
+(new M.C)[Symbol.iterator];

tests/baselines/reference/ES5SymbolProperty3.errors.txt

@@ -0,0 +1,16 @@
+tests/cases/conformance/Symbols/ES5SymbolProperty3.ts(4,5): error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+tests/cases/conformance/Symbols/ES5SymbolProperty3.ts(4,6): error TS2471: A computed property name of the form 'Symbol.iterator' must be of type 'symbol'.
+
+
+==== tests/cases/conformance/Symbols/ES5SymbolProperty3.ts (2 errors) ====
+    var Symbol;
+    
+    class C {
+        [Symbol.iterator]() { }
+        ~~~~~~~~~~~~~~~~~
+!!! error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+         ~~~~~~~~~~~~~~~
+!!! error TS2471: A computed property name of the form 'Symbol.iterator' must be of type 'symbol'.
+    }
+    
+    (new C)[Symbol.iterator]

tests/baselines/reference/ES5SymbolProperty3.js

@@ -0,0 +1,18 @@
+//// [ES5SymbolProperty3.ts]
+var Symbol;
+
+class C {
+    [Symbol.iterator]() { }
+}
+
+(new C)[Symbol.iterator]
+
+//// [ES5SymbolProperty3.js]
+var Symbol;
+var C = (function () {
+    function C() {
+    }
+    C.prototype[Symbol.iterator] = function () { };
+    return C;
+})();
+(new C)[Symbol.iterator];

tests/baselines/reference/ES5SymbolProperty4.errors.txt

@@ -0,0 +1,16 @@
+tests/cases/conformance/Symbols/ES5SymbolProperty4.ts(4,5): error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+tests/cases/conformance/Symbols/ES5SymbolProperty4.ts(4,6): error TS2471: A computed property name of the form 'Symbol.iterator' must be of type 'symbol'.
+
+
+==== tests/cases/conformance/Symbols/ES5SymbolProperty4.ts (2 errors) ====
+    var Symbol: { iterator: string };
+    
+    class C {
+        [Symbol.iterator]() { }
+        ~~~~~~~~~~~~~~~~~
+!!! error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+         ~~~~~~~~~~~~~~~
+!!! error TS2471: A computed property name of the form 'Symbol.iterator' must be of type 'symbol'.
+    }
+    
+    (new C)[Symbol.iterator]

tests/baselines/reference/ES5SymbolProperty4.js

@@ -0,0 +1,18 @@
+//// [ES5SymbolProperty4.ts]
+var Symbol: { iterator: string };
+
+class C {
+    [Symbol.iterator]() { }
+}
+
+(new C)[Symbol.iterator]
+
+//// [ES5SymbolProperty4.js]
+var Symbol;
+var C = (function () {
+    function C() {
+    }
+    C.prototype[Symbol.iterator] = function () { };
+    return C;
+})();
+(new C)[Symbol.iterator];

tests/baselines/reference/ES5SymbolProperty5.errors.txt

@@ -0,0 +1,16 @@
+tests/cases/conformance/Symbols/ES5SymbolProperty5.ts(4,5): error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+tests/cases/conformance/Symbols/ES5SymbolProperty5.ts(7,1): error TS2346: Supplied parameters do not match any signature of call target.
+
+
+==== tests/cases/conformance/Symbols/ES5SymbolProperty5.ts (2 errors) ====
+    var Symbol: { iterator: symbol };
+    
+    class C {
+        [Symbol.iterator]() { }
+        ~~~~~~~~~~~~~~~~~
+!!! error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+    }
+    
+    (new C)[Symbol.iterator](0) // Should error
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2346: Supplied parameters do not match any signature of call target.

tests/baselines/reference/ES5SymbolProperty5.js

@@ -0,0 +1,18 @@
+//// [ES5SymbolProperty5.ts]
+var Symbol: { iterator: symbol };
+
+class C {
+    [Symbol.iterator]() { }
+}
+
+(new C)[Symbol.iterator](0) // Should error
+
+//// [ES5SymbolProperty5.js]
+var Symbol;
+var C = (function () {
+    function C() {
+    }
+    C.prototype[Symbol.iterator] = function () { };
+    return C;
+})();
+(new C)[Symbol.iterator](0); // Should error

tests/baselines/reference/ES5SymbolProperty6.errors.txt

@@ -0,0 +1,17 @@
+tests/cases/conformance/Symbols/ES5SymbolProperty6.ts(2,5): error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+tests/cases/conformance/Symbols/ES5SymbolProperty6.ts(2,6): error TS2304: Cannot find name 'Symbol'.
+tests/cases/conformance/Symbols/ES5SymbolProperty6.ts(5,9): error TS2304: Cannot find name 'Symbol'.
+
+
+==== tests/cases/conformance/Symbols/ES5SymbolProperty6.ts (3 errors) ====
+    class C {
+        [Symbol.iterator]() { }
+        ~~~~~~~~~~~~~~~~~
+!!! error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+         ~~~~~~
+!!! error TS2304: Cannot find name 'Symbol'.
+    }
+    
+    (new C)[Symbol.iterator]
+            ~~~~~~
+!!! error TS2304: Cannot find name 'Symbol'.

tests/baselines/reference/ES5SymbolProperty6.js

@@ -0,0 +1,15 @@
+//// [ES5SymbolProperty6.ts]
+class C {
+    [Symbol.iterator]() { }
+}
+
+(new C)[Symbol.iterator]
+
+//// [ES5SymbolProperty6.js]
+var C = (function () {
+    function C() {
+    }
+    C.prototype[Symbol.iterator] = function () { };
+    return C;
+})();
+(new C)[Symbol.iterator];

tests/baselines/reference/ES5SymbolProperty7.errors.txt

@@ -0,0 +1,16 @@
+tests/cases/conformance/Symbols/ES5SymbolProperty7.ts(4,5): error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+tests/cases/conformance/Symbols/ES5SymbolProperty7.ts(4,6): error TS2471: A computed property name of the form 'Symbol.iterator' must be of type 'symbol'.
+
+
+==== tests/cases/conformance/Symbols/ES5SymbolProperty7.ts (2 errors) ====
+    var Symbol: { iterator: any };
+    
+    class C {
+        [Symbol.iterator]() { }
+        ~~~~~~~~~~~~~~~~~
+!!! error TS1167: Computed property names are only available when targeting ECMAScript 6 and higher.
+         ~~~~~~~~~~~~~~~
+!!! error TS2471: A computed property name of the form 'Symbol.iterator' must be of type 'symbol'.
+    }
+    
+    (new C)[Symbol.iterator]

tests/baselines/reference/ES5SymbolProperty7.js

@@ -0,0 +1,18 @@
+//// [ES5SymbolProperty7.ts]
+var Symbol: { iterator: any };
+
+class C {
+    [Symbol.iterator]() { }
+}
+
+(new C)[Symbol.iterator]
+
+//// [ES5SymbolProperty7.js]
+var Symbol;
+var C = (function () {
+    function C() {
+    }
+    C.prototype[Symbol.iterator] = function () { };
+    return C;
+})();
+(new C)[Symbol.iterator];

tests/baselines/reference/ES5SymbolType1.js

@@ -0,0 +1,7 @@
+//// [ES5SymbolType1.ts]
+var s: symbol;
+s.toString();
+
+//// [ES5SymbolType1.js]
+var s;
+s.toString();

tests/baselines/reference/ES5SymbolType1.types

@@ -0,0 +1,10 @@
+=== tests/cases/conformance/Symbols/ES5SymbolType1.ts ===
+var s: symbol;
+>s : symbol
+
+s.toString();
+>s.toString() : string
+>s.toString : () => string
+>s : symbol
+>toString : () => string
+

tests/baselines/reference/baseTypePrivateMemberClash.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/baseTypePrivateMemberClash.ts(8,11): error TS2320: Interface 'Z' cannot simultaneously extend types 'X' and 'Y'.
-  Named properties 'm' of types 'X' and 'Y' are not identical.
+  Named property 'm' of types 'X' and 'Y' are not identical.
 
 
 ==== tests/cases/compiler/baseTypePrivateMemberClash.ts (1 errors) ====
@@ -13,4 +13,4 @@ tests/cases/compiler/baseTypePrivateMemberClash.ts(8,11): error TS2320: Interfac
     interface Z extends X, Y { }
               ~
 !!! error TS2320: Interface 'Z' cannot simultaneously extend types 'X' and 'Y'.
-!!! error TS2320:   Named properties 'm' of types 'X' and 'Y' are not identical.
+!!! error TS2320:   Named property 'm' of types 'X' and 'Y' are not identical.

tests/baselines/reference/callSignaturesThatDifferOnlyByReturnType2.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesThatDifferOnlyByReturnType2.ts(8,11): error TS2320: Interface 'A' cannot simultaneously extend types 'I<number>' and 'I<string>'.
-  Named properties 'foo' of types 'I<number>' and 'I<string>' are not identical.
+  Named property 'foo' of types 'I<number>' and 'I<string>' are not identical.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesThatDifferOnlyByReturnType2.ts(13,16): error TS2345: Argument of type 'string' is not assignable to parameter of type 'number'.
 
 
@@ -14,7 +14,7 @@ tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesTha
     interface A extends I<number>, I<string> { }
               ~
 !!! error TS2320: Interface 'A' cannot simultaneously extend types 'I<number>' and 'I<string>'.
-!!! error TS2320:   Named properties 'foo' of types 'I<number>' and 'I<string>' are not identical.
+!!! error TS2320:   Named property 'foo' of types 'I<number>' and 'I<string>' are not identical.
     
     var x: A;
     // BUG 822524

tests/baselines/reference/callWithSpread.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/expressions/functionCalls/callWithSpread.ts(52,21): error TS2468: Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher.
+tests/cases/conformance/expressions/functionCalls/callWithSpread.ts(52,21): error TS2472: Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher.
 
 
 ==== tests/cases/conformance/expressions/functionCalls/callWithSpread.ts (1 errors) ====
@@ -55,5 +55,5 @@ tests/cases/conformance/expressions/functionCalls/callWithSpread.ts(52,21): erro
     // Only supported in when target is ES6
     var c = new C(1, 2, ...a);
                         ~~~~
-!!! error TS2468: Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher.
+!!! error TS2472: Spread operator in 'new' expressions is only available when targeting ECMAScript 6 and higher.
     

tests/baselines/reference/computedPropertyNames12.errors.txt

@@ -1,14 +1,14 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(5,5): error TS1166: Computed property names are not allowed in class property declarations.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(6,5): error TS1166: Computed property names are not allowed in class property declarations.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(7,12): error TS1166: Computed property names are not allowed in class property declarations.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(8,5): error TS1166: Computed property names are not allowed in class property declarations.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(9,5): error TS1166: Computed property names are not allowed in class property declarations.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(10,12): error TS1166: Computed property names are not allowed in class property declarations.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(11,5): error TS1166: Computed property names are not allowed in class property declarations.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(12,5): error TS1166: Computed property names are not allowed in class property declarations.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(13,12): error TS1166: Computed property names are not allowed in class property declarations.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(14,5): error TS1166: Computed property names are not allowed in class property declarations.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(15,12): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(5,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(6,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(7,12): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(8,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(9,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(10,12): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(11,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(12,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(13,12): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(14,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(15,12): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts (11 errors) ====
@@ -18,35 +18,35 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames12.ts(15,12)
     class C {
         [s]: number;
         ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         [n] = n;
         ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         static [s + s]: string;
                ~~~~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         [s + n] = 2;
         ~~~~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         [+s]: typeof s;
         ~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         static [""]: number;
                ~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         [0]: number;
         ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         [a]: number;
         ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         static [<any>true]: number;
                ~~~~~~~~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         [`hello bye`] = 0;
         ~~~~~~~~~~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         static [`hello ${a} bye`] = 0
                ~~~~~~~~~~~~~~~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
     }

tests/baselines/reference/computedPropertyNames14.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(3,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(4,12): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(5,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(6,12): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(7,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(8,12): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(3,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(4,12): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(5,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(6,12): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(7,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(8,12): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts (6 errors) ====
@@ -11,20 +11,20 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames14.ts(8,12):
     class C {
         [b]() {}
         ~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         static [true]() { }
                ~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         [[]]() { }
         ~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         static [{}]() { }
                ~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         [undefined]() { }
         ~~~~~~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         static [null]() { }
                ~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
     }

tests/baselines/reference/computedPropertyNames15.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames15.ts(6,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames15.ts(7,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames15.ts(6,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames15.ts(7,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames15.ts (2 errors) ====
@@ -10,8 +10,8 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames15.ts(7,5):
         [p1]() { }
         [p2]() { }
         ~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         [p3]() { }
         ~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
     }

tests/baselines/reference/computedPropertyNames17.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(3,9): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(4,16): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(5,9): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(6,9): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(7,16): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(8,9): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(3,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(4,16): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(5,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(6,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(7,16): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(8,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts (6 errors) ====
@@ -11,20 +11,20 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames17.ts(8,9):
     class C {
         get [b]() { return 0;}
             ~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         static set [true](v) { }
                    ~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         get [[]]() { return 0; }
             ~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         set [{}](v) { }
             ~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         static get [undefined]() { return 0; }
                    ~~~~~~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         set [null](v) { }
             ~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
     }

tests/baselines/reference/computedPropertyNames3.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts(4,12): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts(4,12): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts(5,9): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts(5,9): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts(6,9): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts(5,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts(6,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts(7,16): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts(7,16): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts(7,16): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts (6 errors) ====
@@ -12,19 +12,19 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames3.ts(7,16):
         [0 + 1]() { }
         static [() => { }]() { }
                ~~~~~~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         get [delete id]() { }
             ~~~~~~~~~~~
 !!! error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
             ~~~~~~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         set [[0, 1]](v) { }
             ~~~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         static get [<String>""]() { }
                    ~~~~~~~~~~~~
 !!! error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
                    ~~~~~~~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         static set [id.toString()](v) { }
     }

tests/baselines/reference/computedPropertyNames32.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames32.ts(6,10): error TS2466: A computed property name cannot reference a type parameter from its containing type.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames32.ts(6,10): error TS2467: A computed property name cannot reference a type parameter from its containing type.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames32.ts (1 errors) ====
@@ -9,5 +9,5 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames32.ts(6,10):
         }
         [foo<T>()]() { }
              ~
-!!! error TS2466: A computed property name cannot reference a type parameter from its containing type.
+!!! error TS2467: A computed property name cannot reference a type parameter from its containing type.
     }

tests/baselines/reference/computedPropertyNames35.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames35.ts(4,5): error TS1169: Computed property names are not allowed in interfaces.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames35.ts(4,10): error TS2466: A computed property name cannot reference a type parameter from its containing type.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames35.ts(4,5): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames35.ts(4,10): error TS2467: A computed property name cannot reference a type parameter from its containing type.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames35.ts (2 errors) ====
@@ -8,7 +8,7 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames35.ts(4,10):
         bar(): string;
         [foo<T>()](): void;
         ~~~~~~~~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
              ~
-!!! error TS2466: A computed property name cannot reference a type parameter from its containing type.
+!!! error TS2467: A computed property name cannot reference a type parameter from its containing type.
     }

tests/baselines/reference/computedPropertyNames42.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames42.ts(8,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames42.ts(8,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/es6/computedProperties/computedPropertyNames42.ts(8,5): error TS2411: Property '[""]' of type 'Foo' is not assignable to string index type 'Foo2'.
 
 
@@ -12,7 +12,7 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames42.ts(8,5):
         // Computed properties
         [""]: Foo;
         ~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         ~~~~~~~~~~
 !!! error TS2411: Property '[""]' of type 'Foo' is not assignable to string index type 'Foo2'.
     }

tests/baselines/reference/computedPropertyNames5.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(3,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(4,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(5,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(6,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(7,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(8,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(3,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(4,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(5,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(6,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(7,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(8,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts (6 errors) ====
@@ -11,20 +11,20 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames5.ts(8,5): e
     var v = {
         [b]: 0,
         ~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         [true]: 1,
         ~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         [[]]: 0,
         ~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         [{}]: 0,
         ~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         [undefined]: undefined,
         ~~~~~~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         [null]: null
         ~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
     }

tests/baselines/reference/computedPropertyNames6.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames6.ts(6,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames6.ts(7,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames6.ts(6,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames6.ts(7,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames6.ts (2 errors) ====
@@ -10,8 +10,8 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames6.ts(7,5): e
         [p1]: 0,
         [p2]: 1,
         ~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         [p3]: 2
         ~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
     }

tests/baselines/reference/computedPropertyNames8.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames8.ts(5,9): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames8.ts(6,9): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames8.ts(5,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames8.ts(6,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames8.ts (2 errors) ====
@@ -9,9 +9,9 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames8.ts(6,9): e
         var v = {
             [t]: 0,
             ~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
             [u]: 1
             ~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         };
     }

tests/baselines/reference/computedPropertyNames9.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNames9.ts(9,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNames9.ts(9,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames9.ts (1 errors) ====
@@ -12,5 +12,5 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames9.ts(9,5): e
         [f(0)]: 0,
         [f(true)]: 0
         ~~~~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
     }

tests/baselines/reference/computedPropertyNamesDeclarationEmit3.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesDeclarationEmit3.ts(2,5): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/conformance/es6/computedProperties/computedPropertyNamesDeclarationEmit3.ts(2,5): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNamesDeclarationEmit3.ts (1 errors) ====
     interface I {
         ["" + ""](): void;
         ~~~~~~~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
     }

tests/baselines/reference/computedPropertyNamesDeclarationEmit4.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesDeclarationEmit4.ts(2,5): error TS1170: Computed property names are not allowed in type literals.
+tests/cases/conformance/es6/computedProperties/computedPropertyNamesDeclarationEmit4.ts(2,5): error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNamesDeclarationEmit4.ts (1 errors) ====
     var v: {
         ["" + ""](): void;
         ~~~~~~~~~
-!!! error TS1170: Computed property names are not allowed in type literals.
+!!! error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
     }

tests/baselines/reference/computedPropertyNamesOnOverloads.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesOnOverloads.ts(4,5): error TS1168: Computed property names are not allowed in method overloads.
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesOnOverloads.ts(5,5): error TS1168: Computed property names are not allowed in method overloads.
+tests/cases/conformance/es6/computedProperties/computedPropertyNamesOnOverloads.ts(4,5): error TS1168: A computed property name in a method overload must directly refer to a built-in symbol.
+tests/cases/conformance/es6/computedProperties/computedPropertyNamesOnOverloads.ts(5,5): error TS1168: A computed property name in a method overload must directly refer to a built-in symbol.
 
 
 ==== tests/cases/conformance/es6/computedProperties/computedPropertyNamesOnOverloads.ts (2 errors) ====
@@ -8,9 +8,9 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNamesOnOverloads.
     class C {
         [methodName](v: string);
         ~~~~~~~~~~~~
-!!! error TS1168: Computed property names are not allowed in method overloads.
+!!! error TS1168: A computed property name in a method overload must directly refer to a built-in symbol.
         [methodName]();
         ~~~~~~~~~~~~
-!!! error TS1168: Computed property names are not allowed in method overloads.
+!!! error TS1168: A computed property name in a method overload must directly refer to a built-in symbol.
         [methodName](v?: string) { }
     }

tests/baselines/reference/conflictingMemberTypesInBases.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/conflictingMemberTypesInBases.ts(12,11): error TS2320: Interface 'E' cannot simultaneously extend types 'B' and 'D'.
-  Named properties 'm' of types 'B' and 'D' are not identical.
+  Named property 'm' of types 'B' and 'D' are not identical.
 
 
 ==== tests/cases/compiler/conflictingMemberTypesInBases.ts (1 errors) ====
@@ -17,6 +17,6 @@ tests/cases/compiler/conflictingMemberTypesInBases.ts(12,11): error TS2320: Inte
     interface E extends B { } // Error here for extending B and D
               ~
 !!! error TS2320: Interface 'E' cannot simultaneously extend types 'B' and 'D'.
-!!! error TS2320:   Named properties 'm' of types 'B' and 'D' are not identical.
+!!! error TS2320:   Named property 'm' of types 'B' and 'D' are not identical.
     interface E extends D { } // No duplicate error here
     

tests/baselines/reference/constDeclarationShadowedByVarDeclaration.errors.txt

@@ -1,6 +1,6 @@
-tests/cases/compiler/constDeclarationShadowedByVarDeclaration.ts(7,9): error TS2477: Cannot initialize outer scoped variable 'x' in the same scope as block scoped declaration 'x'.
-tests/cases/compiler/constDeclarationShadowedByVarDeclaration.ts(15,13): error TS2477: Cannot initialize outer scoped variable 'y' in the same scope as block scoped declaration 'y'.
-tests/cases/compiler/constDeclarationShadowedByVarDeclaration.ts(22,7): error TS2477: Cannot initialize outer scoped variable 'z' in the same scope as block scoped declaration 'z'.
+tests/cases/compiler/constDeclarationShadowedByVarDeclaration.ts(7,9): error TS2481: Cannot initialize outer scoped variable 'x' in the same scope as block scoped declaration 'x'.
+tests/cases/compiler/constDeclarationShadowedByVarDeclaration.ts(15,13): error TS2481: Cannot initialize outer scoped variable 'y' in the same scope as block scoped declaration 'y'.
+tests/cases/compiler/constDeclarationShadowedByVarDeclaration.ts(22,7): error TS2481: Cannot initialize outer scoped variable 'z' in the same scope as block scoped declaration 'z'.
 
 
 ==== tests/cases/compiler/constDeclarationShadowedByVarDeclaration.ts (3 errors) ====
@@ -12,7 +12,7 @@ tests/cases/compiler/constDeclarationShadowedByVarDeclaration.ts(22,7): error TS
     
         var x = 0;
             ~
-!!! error TS2477: Cannot initialize outer scoped variable 'x' in the same scope as block scoped declaration 'x'.
+!!! error TS2481: Cannot initialize outer scoped variable 'x' in the same scope as block scoped declaration 'x'.
     }
     
     
@@ -22,7 +22,7 @@ tests/cases/compiler/constDeclarationShadowedByVarDeclaration.ts(22,7): error TS
         {
             var y = 0;
                 ~
-!!! error TS2477: Cannot initialize outer scoped variable 'y' in the same scope as block scoped declaration 'y'.
+!!! error TS2481: Cannot initialize outer scoped variable 'y' in the same scope as block scoped declaration 'y'.
         }
     }
     
@@ -31,5 +31,5 @@ tests/cases/compiler/constDeclarationShadowedByVarDeclaration.ts(22,7): error TS
       const z = 0;
       var z = 0
           ~
-!!! error TS2477: Cannot initialize outer scoped variable 'z' in the same scope as block scoped declaration 'z'.
+!!! error TS2481: Cannot initialize outer scoped variable 'z' in the same scope as block scoped declaration 'z'.
     }

tests/baselines/reference/constEnumBadPropertyNames.errors.txt

@@ -1,8 +1,8 @@
-tests/cases/compiler/constEnumBadPropertyNames.ts(2,11): error TS2475: Property 'B' does not exist on 'const' enum 'E'.
+tests/cases/compiler/constEnumBadPropertyNames.ts(2,11): error TS2479: Property 'B' does not exist on 'const' enum 'E'.
 
 
 ==== tests/cases/compiler/constEnumBadPropertyNames.ts (1 errors) ====
     const enum E { A }
     var x = E["B"]
               ~~~
-!!! error TS2475: Property 'B' does not exist on 'const' enum 'E'.
+!!! error TS2479: Property 'B' does not exist on 'const' enum 'E'.

tests/baselines/reference/constEnumErrors.errors.txt

@@ -1,16 +1,16 @@
 tests/cases/compiler/constEnumErrors.ts(1,12): error TS2300: Duplicate identifier 'E'.
 tests/cases/compiler/constEnumErrors.ts(5,8): error TS2300: Duplicate identifier 'E'.
-tests/cases/compiler/constEnumErrors.ts(12,9): error TS2470: In 'const' enum declarations member initializer must be constant expression.
-tests/cases/compiler/constEnumErrors.ts(14,9): error TS2470: In 'const' enum declarations member initializer must be constant expression.
-tests/cases/compiler/constEnumErrors.ts(15,10): error TS2470: In 'const' enum declarations member initializer must be constant expression.
-tests/cases/compiler/constEnumErrors.ts(22,13): error TS2472: A const enum member can only be accessed using a string literal.
-tests/cases/compiler/constEnumErrors.ts(24,13): error TS2472: A const enum member can only be accessed using a string literal.
-tests/cases/compiler/constEnumErrors.ts(26,9): error TS2471: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
-tests/cases/compiler/constEnumErrors.ts(27,10): error TS2471: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
-tests/cases/compiler/constEnumErrors.ts(32,5): error TS2471: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
-tests/cases/compiler/constEnumErrors.ts(40,9): error TS2473: 'const' enum member initializer was evaluated to a non-finite value.
-tests/cases/compiler/constEnumErrors.ts(41,9): error TS2473: 'const' enum member initializer was evaluated to a non-finite value.
-tests/cases/compiler/constEnumErrors.ts(42,9): error TS2474: 'const' enum member initializer was evaluated to disallowed value 'NaN'.
+tests/cases/compiler/constEnumErrors.ts(12,9): error TS2474: In 'const' enum declarations member initializer must be constant expression.
+tests/cases/compiler/constEnumErrors.ts(14,9): error TS2474: In 'const' enum declarations member initializer must be constant expression.
+tests/cases/compiler/constEnumErrors.ts(15,10): error TS2474: In 'const' enum declarations member initializer must be constant expression.
+tests/cases/compiler/constEnumErrors.ts(22,13): error TS2476: A const enum member can only be accessed using a string literal.
+tests/cases/compiler/constEnumErrors.ts(24,13): error TS2476: A const enum member can only be accessed using a string literal.
+tests/cases/compiler/constEnumErrors.ts(26,9): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+tests/cases/compiler/constEnumErrors.ts(27,10): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+tests/cases/compiler/constEnumErrors.ts(32,5): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+tests/cases/compiler/constEnumErrors.ts(40,9): error TS2477: 'const' enum member initializer was evaluated to a non-finite value.
+tests/cases/compiler/constEnumErrors.ts(41,9): error TS2477: 'const' enum member initializer was evaluated to a non-finite value.
+tests/cases/compiler/constEnumErrors.ts(42,9): error TS2478: 'const' enum member initializer was evaluated to disallowed value 'NaN'.
 
 
 ==== tests/cases/compiler/constEnumErrors.ts (13 errors) ====
@@ -31,14 +31,14 @@ tests/cases/compiler/constEnumErrors.ts(42,9): error TS2474: 'const' enum member
         // forward reference to the element of the same enum
         X = Y, 
             ~
-!!! error TS2470: In 'const' enum declarations member initializer must be constant expression.
+!!! error TS2474: In 'const' enum declarations member initializer must be constant expression.
         // forward reference to the element of the same enum
         Y = E1.Z,
             ~~~~
-!!! error TS2470: In 'const' enum declarations member initializer must be constant expression.
+!!! error TS2474: In 'const' enum declarations member initializer must be constant expression.
         Y1 = E1["Z"]
              ~~~~~~~
-!!! error TS2470: In 'const' enum declarations member initializer must be constant expression.
+!!! error TS2474: In 'const' enum declarations member initializer must be constant expression.
     }
     
     const enum E2 {
@@ -47,25 +47,25 @@ tests/cases/compiler/constEnumErrors.ts(42,9): error TS2474: 'const' enum member
     
     var y0 = E2[1]
                 ~
-!!! error TS2472: A const enum member can only be accessed using a string literal.
+!!! error TS2476: A const enum member can only be accessed using a string literal.
     var name = "A";
     var y1 = E2[name];
                 ~~~~
-!!! error TS2472: A const enum member can only be accessed using a string literal.
+!!! error TS2476: A const enum member can only be accessed using a string literal.
     
     var x = E2;
             ~~
-!!! error TS2471: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+!!! error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
     var y = [E2];
              ~~
-!!! error TS2471: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+!!! error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
     
     function foo(t: any): void {
     }
     
     foo(E2);
         ~~
-!!! error TS2471: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+!!! error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
     
     const enum NaNOrInfinity {
         A = 9007199254740992,
@@ -75,11 +75,11 @@ tests/cases/compiler/constEnumErrors.ts(42,9): error TS2474: 'const' enum member
         E = D * D,
         F = E * E, // overflow
             ~~~~~
-!!! error TS2473: 'const' enum member initializer was evaluated to a non-finite value.
+!!! error TS2477: 'const' enum member initializer was evaluated to a non-finite value.
         G = 1 / 0, // overflow
             ~~~~~
-!!! error TS2473: 'const' enum member initializer was evaluated to a non-finite value.
+!!! error TS2477: 'const' enum member initializer was evaluated to a non-finite value.
         H = 0 / 0  // NaN
             ~~~~~
-!!! error TS2474: 'const' enum member initializer was evaluated to disallowed value 'NaN'.
+!!! error TS2478: 'const' enum member initializer was evaluated to disallowed value 'NaN'.
     }

tests/baselines/reference/genericAndNonGenericInheritedSignature1.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/genericAndNonGenericInheritedSignature1.ts(7,11): error TS2320: Interface 'Hello' cannot simultaneously extend types 'Foo' and 'Bar'.
-  Named properties 'f' of types 'Foo' and 'Bar' are not identical.
+  Named property 'f' of types 'Foo' and 'Bar' are not identical.
 
 
 ==== tests/cases/compiler/genericAndNonGenericInheritedSignature1.ts (1 errors) ====
@@ -12,6 +12,6 @@ tests/cases/compiler/genericAndNonGenericInheritedSignature1.ts(7,11): error TS2
     interface Hello extends Foo, Bar {
               ~~~~~
 !!! error TS2320: Interface 'Hello' cannot simultaneously extend types 'Foo' and 'Bar'.
-!!! error TS2320:   Named properties 'f' of types 'Foo' and 'Bar' are not identical.
+!!! error TS2320:   Named property 'f' of types 'Foo' and 'Bar' are not identical.
     }
     

tests/baselines/reference/genericAndNonGenericInheritedSignature2.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/genericAndNonGenericInheritedSignature2.ts(7,11): error TS2320: Interface 'Hello' cannot simultaneously extend types 'Bar' and 'Foo'.
-  Named properties 'f' of types 'Bar' and 'Foo' are not identical.
+  Named property 'f' of types 'Bar' and 'Foo' are not identical.
 
 
 ==== tests/cases/compiler/genericAndNonGenericInheritedSignature2.ts (1 errors) ====
@@ -12,6 +12,6 @@ tests/cases/compiler/genericAndNonGenericInheritedSignature2.ts(7,11): error TS2
     interface Hello extends Bar, Foo {
               ~~~~~
 !!! error TS2320: Interface 'Hello' cannot simultaneously extend types 'Bar' and 'Foo'.
-!!! error TS2320:   Named properties 'f' of types 'Bar' and 'Foo' are not identical.
+!!! error TS2320:   Named property 'f' of types 'Bar' and 'Foo' are not identical.
     }
     

tests/baselines/reference/giant.errors.txt

@@ -16,7 +16,7 @@ tests/cases/compiler/giant.ts(34,16): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(35,12): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(36,16): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/giant.ts(36,16): error TS2300: Duplicate identifier 'tgF'.
-tests/cases/compiler/giant.ts(61,5): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/compiler/giant.ts(61,5): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/compiler/giant.ts(61,6): error TS2304: Cannot find name 'p'.
 tests/cases/compiler/giant.ts(62,5): error TS1021: An index signature must have a type annotation.
 tests/cases/compiler/giant.ts(63,6): error TS1096: An index signature must have exactly one parameter.
@@ -39,7 +39,7 @@ tests/cases/compiler/giant.ts(98,20): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(99,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(100,20): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/giant.ts(100,20): error TS2300: Duplicate identifier 'tgF'.
-tests/cases/compiler/giant.ts(125,9): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/compiler/giant.ts(125,9): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/compiler/giant.ts(125,10): error TS2304: Cannot find name 'p'.
 tests/cases/compiler/giant.ts(126,9): error TS1021: An index signature must have a type annotation.
 tests/cases/compiler/giant.ts(127,10): error TS1096: An index signature must have exactly one parameter.
@@ -63,7 +63,7 @@ tests/cases/compiler/giant.ts(177,20): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(178,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(179,20): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/giant.ts(179,20): error TS2300: Duplicate identifier 'tgF'.
-tests/cases/compiler/giant.ts(204,9): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/compiler/giant.ts(204,9): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/compiler/giant.ts(204,10): error TS2304: Cannot find name 'p'.
 tests/cases/compiler/giant.ts(205,9): error TS1021: An index signature must have a type annotation.
 tests/cases/compiler/giant.ts(206,10): error TS1096: An index signature must have exactly one parameter.
@@ -119,7 +119,7 @@ tests/cases/compiler/giant.ts(292,16): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(293,12): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(294,16): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/giant.ts(294,16): error TS2300: Duplicate identifier 'tgF'.
-tests/cases/compiler/giant.ts(319,5): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/compiler/giant.ts(319,5): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/compiler/giant.ts(319,6): error TS2304: Cannot find name 'p'.
 tests/cases/compiler/giant.ts(320,5): error TS1021: An index signature must have a type annotation.
 tests/cases/compiler/giant.ts(321,6): error TS1096: An index signature must have exactly one parameter.
@@ -142,7 +142,7 @@ tests/cases/compiler/giant.ts(356,20): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(357,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(358,20): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/giant.ts(358,20): error TS2300: Duplicate identifier 'tgF'.
-tests/cases/compiler/giant.ts(383,9): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/compiler/giant.ts(383,9): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/compiler/giant.ts(383,10): error TS2304: Cannot find name 'p'.
 tests/cases/compiler/giant.ts(384,9): error TS1021: An index signature must have a type annotation.
 tests/cases/compiler/giant.ts(385,10): error TS1096: An index signature must have exactly one parameter.
@@ -166,7 +166,7 @@ tests/cases/compiler/giant.ts(435,20): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(436,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(437,20): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/giant.ts(437,20): error TS2300: Duplicate identifier 'tgF'.
-tests/cases/compiler/giant.ts(462,9): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/compiler/giant.ts(462,9): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/compiler/giant.ts(462,10): error TS2304: Cannot find name 'p'.
 tests/cases/compiler/giant.ts(463,9): error TS1021: An index signature must have a type annotation.
 tests/cases/compiler/giant.ts(464,10): error TS1096: An index signature must have exactly one parameter.
@@ -238,7 +238,7 @@ tests/cases/compiler/giant.ts(556,21): error TS1036: Statements are not allowed
 tests/cases/compiler/giant.ts(558,24): error TS1184: An implementation cannot be declared in ambient contexts.
 tests/cases/compiler/giant.ts(561,21): error TS1184: An implementation cannot be declared in ambient contexts.
 tests/cases/compiler/giant.ts(563,21): error TS1184: An implementation cannot be declared in ambient contexts.
-tests/cases/compiler/giant.ts(587,9): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/compiler/giant.ts(587,9): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/compiler/giant.ts(587,10): error TS2304: Cannot find name 'p'.
 tests/cases/compiler/giant.ts(588,9): error TS1021: An index signature must have a type annotation.
 tests/cases/compiler/giant.ts(589,10): error TS1096: An index signature must have exactly one parameter.
@@ -255,7 +255,7 @@ tests/cases/compiler/giant.ts(621,26): error TS1184: An implementation cannot be
 tests/cases/compiler/giant.ts(623,24): error TS1184: An implementation cannot be declared in ambient contexts.
 tests/cases/compiler/giant.ts(626,21): error TS1184: An implementation cannot be declared in ambient contexts.
 tests/cases/compiler/giant.ts(628,21): error TS1184: An implementation cannot be declared in ambient contexts.
-tests/cases/compiler/giant.ts(653,9): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/compiler/giant.ts(653,9): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/compiler/giant.ts(653,10): error TS2304: Cannot find name 'p'.
 tests/cases/compiler/giant.ts(654,9): error TS1021: An index signature must have a type annotation.
 tests/cases/compiler/giant.ts(655,10): error TS1096: An index signature must have exactly one parameter.
@@ -364,7 +364,7 @@ tests/cases/compiler/giant.ts(676,30): error TS1184: An implementation cannot be
         //Index Signature
         [p];
         ~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'p'.
         [p1: string];
@@ -474,7 +474,7 @@ tests/cases/compiler/giant.ts(676,30): error TS1184: An implementation cannot be
             //Index Signature
             [p];
             ~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
              ~
 !!! error TS2304: Cannot find name 'p'.
             [p1: string];
@@ -601,7 +601,7 @@ tests/cases/compiler/giant.ts(676,30): error TS1184: An implementation cannot be
             //Index Signature
             [p];
             ~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
              ~
 !!! error TS2304: Cannot find name 'p'.
             [p1: string];
@@ -828,7 +828,7 @@ tests/cases/compiler/giant.ts(676,30): error TS1184: An implementation cannot be
         //Index Signature
         [p];
         ~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'p'.
         [p1: string];
@@ -938,7 +938,7 @@ tests/cases/compiler/giant.ts(676,30): error TS1184: An implementation cannot be
             //Index Signature
             [p];
             ~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
              ~
 !!! error TS2304: Cannot find name 'p'.
             [p1: string];
@@ -1065,7 +1065,7 @@ tests/cases/compiler/giant.ts(676,30): error TS1184: An implementation cannot be
             //Index Signature
             [p];
             ~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
              ~
 !!! error TS2304: Cannot find name 'p'.
             [p1: string];
@@ -1334,7 +1334,7 @@ tests/cases/compiler/giant.ts(676,30): error TS1184: An implementation cannot be
             //Index Signature
             [p];
             ~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
              ~
 !!! error TS2304: Cannot find name 'p'.
             [p1: string];
@@ -1434,7 +1434,7 @@ tests/cases/compiler/giant.ts(676,30): error TS1184: An implementation cannot be
             //Index Signature
             [p];
             ~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
              ~
 !!! error TS2304: Cannot find name 'p'.
             [p1: string];

tests/baselines/reference/inOperatorWithInvalidOperands.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(12,11): error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
-tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(13,11): error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
-tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(14,11): error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
-tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(16,11): error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
-tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(17,11): error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
-tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(19,11): error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
-tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(20,11): error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
+tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(12,11): error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
+tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(13,11): error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
+tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(14,11): error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
+tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(16,11): error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
+tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(17,11): error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
+tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(19,11): error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
+tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(20,11): error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
 tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(30,16): error TS2361: The right-hand side of an 'in' expression must be of type 'any', an object type or a type parameter
 tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(31,16): error TS2361: The right-hand side of an 'in' expression must be of type 'any', an object type or a type parameter
 tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(32,16): error TS2361: The right-hand side of an 'in' expression must be of type 'any', an object type or a type parameter
@@ -15,7 +15,7 @@ tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInv
 tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(37,16): error TS2361: The right-hand side of an 'in' expression must be of type 'any', an object type or a type parameter
 tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(38,16): error TS2361: The right-hand side of an 'in' expression must be of type 'any', an object type or a type parameter
 tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(39,17): error TS2361: The right-hand side of an 'in' expression must be of type 'any', an object type or a type parameter
-tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(43,11): error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
+tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(43,11): error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
 tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInvalidOperands.ts(43,17): error TS2361: The right-hand side of an 'in' expression must be of type 'any', an object type or a type parameter
 
 
@@ -33,27 +33,27 @@ tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInv
     
     var ra1 = a1 in x;
               ~~
-!!! error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
+!!! error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
     var ra2 = a2 in x;
               ~~
-!!! error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
+!!! error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
     var ra3 = a3 in x;
               ~~
-!!! error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
+!!! error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
     var ra4 = a4 in x;
     var ra5 = null in x;
               ~~~~
-!!! error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
+!!! error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
     var ra6 = undefined in x;
               ~~~~~~~~~
-!!! error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
+!!! error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
     var ra7 = E.a in x;
     var ra8 = false in x;
               ~~~~~
-!!! error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
+!!! error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
     var ra9 = {} in x;
               ~~
-!!! error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
+!!! error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
     
     // invalid right operands
     // the right operand is required to be of type Any, an object type, or a type parameter type
@@ -98,6 +98,6 @@ tests/cases/conformance/expressions/binaryOperators/inOperator/inOperatorWithInv
     // both operands are invalid
     var rc1 = {} in '';
               ~~
-!!! error TS2360: The left-hand side of an 'in' expression must be of types 'any', 'string' or 'number'.
+!!! error TS2360: The left-hand side of an 'in' expression must be of type 'any', 'string', 'number', or 'symbol'.
                     ~~
 !!! error TS2361: The right-hand side of an 'in' expression must be of type 'any', an object type or a type parameter

tests/baselines/reference/indexSignatureMustHaveTypeAnnotation.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(3,5): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(3,5): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(3,6): error TS2304: Cannot find name 'x'.
 tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(4,5): error TS1021: An index signature must have a type annotation.
-tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(9,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(9,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(9,6): error TS2304: Cannot find name 'x'.
 tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(14,5): error TS1021: An index signature must have a type annotation.
 
@@ -11,7 +11,7 @@ tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(14,5): error TS1021
         // Used to be indexer, now it is a computed property
         [x]: string;
         ~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'x'.
         [x: string];
@@ -23,7 +23,7 @@ tests/cases/compiler/indexSignatureMustHaveTypeAnnotation.ts(14,5): error TS1021
         // Used to be indexer, now it is a computed property
         [x]: string
         ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'x'.
         

tests/baselines/reference/indexSignatureWithInitializer.errors.txt

@@ -1,6 +1,6 @@
-tests/cases/compiler/indexSignatureWithInitializer.ts(3,5): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/compiler/indexSignatureWithInitializer.ts(3,5): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/compiler/indexSignatureWithInitializer.ts(3,6): error TS2304: Cannot find name 'x'.
-tests/cases/compiler/indexSignatureWithInitializer.ts(7,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/compiler/indexSignatureWithInitializer.ts(7,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/compiler/indexSignatureWithInitializer.ts(7,6): error TS2304: Cannot find name 'x'.
 
 
@@ -9,7 +9,7 @@ tests/cases/compiler/indexSignatureWithInitializer.ts(7,6): error TS2304: Cannot
     interface I {
         [x = '']: string;
         ~~~~~~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'x'.
     }
@@ -17,7 +17,7 @@ tests/cases/compiler/indexSignatureWithInitializer.ts(7,6): error TS2304: Cannot
     class C {
         [x = 0]: string
         ~~~~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'x'.
     }

tests/baselines/reference/indexTypeCheck.errors.txt

@@ -5,7 +5,7 @@ tests/cases/compiler/indexTypeCheck.ts(22,2): error TS2413: Numeric index type '
 tests/cases/compiler/indexTypeCheck.ts(27,2): error TS2413: Numeric index type 'number' is not assignable to string index type 'string'.
 tests/cases/compiler/indexTypeCheck.ts(32,3): error TS1096: An index signature must have exactly one parameter.
 tests/cases/compiler/indexTypeCheck.ts(36,3): error TS1023: An index signature parameter type must be 'string' or 'number'.
-tests/cases/compiler/indexTypeCheck.ts(51,1): error TS2342: An index expression argument must be of type 'string', 'number', or 'any'.
+tests/cases/compiler/indexTypeCheck.ts(51,1): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol, or 'any'.
 
 
 ==== tests/cases/compiler/indexTypeCheck.ts (8 errors) ====
@@ -75,7 +75,7 @@ tests/cases/compiler/indexTypeCheck.ts(51,1): error TS2342: An index expression
     
     yellow[blue]; // error
     ~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', or 'any'.
+!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol, or 'any'.
     
     var x:number[];
     x[0];

tests/baselines/reference/indexWithoutParamType2.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/indexWithoutParamType2.ts(3,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/compiler/indexWithoutParamType2.ts(3,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/compiler/indexWithoutParamType2.ts(3,6): error TS2304: Cannot find name 'x'.
 
 
@@ -7,7 +7,7 @@ tests/cases/compiler/indexWithoutParamType2.ts(3,6): error TS2304: Cannot find n
         // Used to be indexer, now it is a computed property
         [x]: string
         ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'x'.
     }

tests/baselines/reference/inheritSameNamePrivatePropertiesFromDifferentOrigins.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/inheritSameNamePrivatePropertiesFromDifferentOrigins.ts(9,11): error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'.
-  Named properties 'x' of types 'C' and 'C2' are not identical.
+  Named property 'x' of types 'C' and 'C2' are not identical.
 
 
 ==== tests/cases/compiler/inheritSameNamePrivatePropertiesFromDifferentOrigins.ts (1 errors) ====
@@ -14,6 +14,6 @@ tests/cases/compiler/inheritSameNamePrivatePropertiesFromDifferentOrigins.ts(9,1
     interface A extends C, C2 { // error
               ~
 !!! error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'.
-!!! error TS2320:   Named properties 'x' of types 'C' and 'C2' are not identical.
+!!! error TS2320:   Named property 'x' of types 'C' and 'C2' are not identical.
         y: string;
     }

tests/baselines/reference/inheritSameNamePropertiesWithDifferentOptionality.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/inheritSameNamePropertiesWithDifferentOptionality.ts(9,11): error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'.
-  Named properties 'x' of types 'C' and 'C2' are not identical.
+  Named property 'x' of types 'C' and 'C2' are not identical.
 
 
 ==== tests/cases/compiler/inheritSameNamePropertiesWithDifferentOptionality.ts (1 errors) ====
@@ -14,6 +14,6 @@ tests/cases/compiler/inheritSameNamePropertiesWithDifferentOptionality.ts(9,11):
     interface A extends C, C2 { // error
               ~
 !!! error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'.
-!!! error TS2320:   Named properties 'x' of types 'C' and 'C2' are not identical.
+!!! error TS2320:   Named property 'x' of types 'C' and 'C2' are not identical.
         y: string;
     }

tests/baselines/reference/inheritSameNamePropertiesWithDifferentVisibility.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/inheritSameNamePropertiesWithDifferentVisibility.ts(9,11): error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'.
-  Named properties 'x' of types 'C' and 'C2' are not identical.
+  Named property 'x' of types 'C' and 'C2' are not identical.
 
 
 ==== tests/cases/compiler/inheritSameNamePropertiesWithDifferentVisibility.ts (1 errors) ====
@@ -14,6 +14,6 @@ tests/cases/compiler/inheritSameNamePropertiesWithDifferentVisibility.ts(9,11):
     interface A extends C, C2 { // error
               ~
 !!! error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'.
-!!! error TS2320:   Named properties 'x' of types 'C' and 'C2' are not identical.
+!!! error TS2320:   Named property 'x' of types 'C' and 'C2' are not identical.
         y: string;
     }

tests/baselines/reference/interfaceDeclaration1.errors.txt

@@ -7,7 +7,7 @@ tests/cases/compiler/interfaceDeclaration1.ts(35,7): error TS2420: Class 'C1' in
   Property 'prototype' is missing in type 'C1'.
 tests/cases/compiler/interfaceDeclaration1.ts(41,11): error TS2310: Type 'i8' recursively references itself as a base type.
 tests/cases/compiler/interfaceDeclaration1.ts(52,11): error TS2320: Interface 'i12' cannot simultaneously extend types 'i10' and 'i11'.
-  Named properties 'foo' of types 'i10' and 'i11' are not identical.
+  Named property 'foo' of types 'i10' and 'i11' are not identical.
 
 
 ==== tests/cases/compiler/interfaceDeclaration1.ts (8 errors) ====
@@ -80,5 +80,5 @@ tests/cases/compiler/interfaceDeclaration1.ts(52,11): error TS2320: Interface 'i
     interface i12 extends i10, i11 { }
               ~~~
 !!! error TS2320: Interface 'i12' cannot simultaneously extend types 'i10' and 'i11'.
-!!! error TS2320:   Named properties 'foo' of types 'i10' and 'i11' are not identical.
+!!! error TS2320:   Named property 'foo' of types 'i10' and 'i11' are not identical.
     

tests/baselines/reference/interfaceExtendingClassWithPrivates2.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithPrivates2.ts(9,11): error TS2320: Interface 'I3' cannot simultaneously extend types 'Foo' and 'Bar'.
-  Named properties 'x' of types 'Foo' and 'Bar' are not identical.
+  Named property 'x' of types 'Foo' and 'Bar' are not identical.
 tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithPrivates2.ts(12,11): error TS2430: Interface 'I4' incorrectly extends interface 'Bar'.
   Property 'x' is private in type 'Bar' but not in type 'I4'.
 tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithPrivates2.ts(12,11): error TS2430: Interface 'I4' incorrectly extends interface 'Foo'.
@@ -20,7 +20,7 @@ tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtending
     interface I3 extends Foo, Bar { // error
               ~~
 !!! error TS2320: Interface 'I3' cannot simultaneously extend types 'Foo' and 'Bar'.
-!!! error TS2320:   Named properties 'x' of types 'Foo' and 'Bar' are not identical.
+!!! error TS2320:   Named property 'x' of types 'Foo' and 'Bar' are not identical.
     }
     
     interface I4 extends Foo, Bar { // error

tests/baselines/reference/interfaceExtendingClassWithProtecteds2.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts(9,11): error TS2320: Interface 'I3' cannot simultaneously extend types 'Foo' and 'Bar'.
-  Named properties 'x' of types 'Foo' and 'Bar' are not identical.
+  Named property 'x' of types 'Foo' and 'Bar' are not identical.
 tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts(12,11): error TS2430: Interface 'I4' incorrectly extends interface 'Bar'.
   Property 'x' is protected but type 'I4' is not a class derived from 'Bar'.
 tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts(12,11): error TS2430: Interface 'I4' incorrectly extends interface 'Foo'.
@@ -20,7 +20,7 @@ tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtending
     interface I3 extends Foo, Bar { // error
               ~~
 !!! error TS2320: Interface 'I3' cannot simultaneously extend types 'Foo' and 'Bar'.
-!!! error TS2320:   Named properties 'x' of types 'Foo' and 'Bar' are not identical.
+!!! error TS2320:   Named property 'x' of types 'Foo' and 'Bar' are not identical.
     }
     
     interface I4 extends Foo, Bar { // error

tests/baselines/reference/interfaceImplementation7.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/interfaceImplementation7.ts(4,11): error TS2320: Interface 'i3' cannot simultaneously extend types 'i1' and 'i2'.
-  Named properties 'name' of types 'i1' and 'i2' are not identical.
+  Named property 'name' of types 'i1' and 'i2' are not identical.
 tests/cases/compiler/interfaceImplementation7.ts(7,7): error TS2420: Class 'C1' incorrectly implements interface 'i4'.
   Types of property 'name' are incompatible.
     Type '() => string' is not assignable to type '() => { s: string; n: number; }'.
@@ -14,7 +14,7 @@ tests/cases/compiler/interfaceImplementation7.ts(7,7): error TS2420: Class 'C1'
     interface i3 extends i1, i2 { }
               ~~
 !!! error TS2320: Interface 'i3' cannot simultaneously extend types 'i1' and 'i2'.
-!!! error TS2320:   Named properties 'name' of types 'i1' and 'i2' are not identical.
+!!! error TS2320:   Named property 'name' of types 'i1' and 'i2' are not identical.
     interface i4 extends i1, i2 { name(): { s: string; n: number; }; }
     
     class C1 implements i4 {

tests/baselines/reference/interfacePropertiesWithSameName2.errors.txt

@@ -1,7 +1,7 @@
 tests/cases/compiler/interfacePropertiesWithSameName2.ts(10,11): error TS2320: Interface 'MoverShaker' cannot simultaneously extend types 'Mover' and 'Shaker'.
-  Named properties 'getStatus' of types 'Mover' and 'Shaker' are not identical.
+  Named property 'getStatus' of types 'Mover' and 'Shaker' are not identical.
 tests/cases/compiler/interfacePropertiesWithSameName2.ts(26,11): error TS2320: Interface 'MoverShaker2' cannot simultaneously extend types 'Mover' and 'Shaker'.
-  Named properties 'getStatus' of types 'Mover' and 'Shaker' are not identical.
+  Named property 'getStatus' of types 'Mover' and 'Shaker' are not identical.
 
 
 ==== tests/cases/compiler/interfacePropertiesWithSameName2.ts (2 errors) ====
@@ -17,7 +17,7 @@ tests/cases/compiler/interfacePropertiesWithSameName2.ts(26,11): error TS2320: I
     interface MoverShaker extends Mover, Shaker {
               ~~~~~~~~~~~
 !!! error TS2320: Interface 'MoverShaker' cannot simultaneously extend types 'Mover' and 'Shaker'.
-!!! error TS2320:   Named properties 'getStatus' of types 'Mover' and 'Shaker' are not identical.
+!!! error TS2320:   Named property 'getStatus' of types 'Mover' and 'Shaker' are not identical.
     
     }
     
@@ -36,7 +36,7 @@ tests/cases/compiler/interfacePropertiesWithSameName2.ts(26,11): error TS2320: I
     interface MoverShaker2 extends MoversAndShakers.Mover, MoversAndShakers.Shaker { } // error
               ~~~~~~~~~~~~
 !!! error TS2320: Interface 'MoverShaker2' cannot simultaneously extend types 'Mover' and 'Shaker'.
-!!! error TS2320:   Named properties 'getStatus' of types 'Mover' and 'Shaker' are not identical.
+!!! error TS2320:   Named property 'getStatus' of types 'Mover' and 'Shaker' are not identical.
     
     interface MoverShaker3 extends MoversAndShakers.Mover, MoversAndShakers.Shaker {
         getStatus(): { speed: number; frequency: number; }; // ok because this getStatus overrides the conflicting ones above

tests/baselines/reference/interfacePropertiesWithSameName3.errors.txt

@@ -1,7 +1,7 @@
 tests/cases/compiler/interfacePropertiesWithSameName3.ts(3,11): error TS2320: Interface 'F' cannot simultaneously extend types 'E' and 'D'.
-  Named properties 'a' of types 'E' and 'D' are not identical.
+  Named property 'a' of types 'E' and 'D' are not identical.
 tests/cases/compiler/interfacePropertiesWithSameName3.ts(7,11): error TS2320: Interface 'F2' cannot simultaneously extend types 'E2' and 'D2'.
-  Named properties 'a' of types 'E2' and 'D2' are not identical.
+  Named property 'a' of types 'E2' and 'D2' are not identical.
 
 
 ==== tests/cases/compiler/interfacePropertiesWithSameName3.ts (2 errors) ====
@@ -10,12 +10,12 @@ tests/cases/compiler/interfacePropertiesWithSameName3.ts(7,11): error TS2320: In
     interface F extends E, D { } // error
               ~
 !!! error TS2320: Interface 'F' cannot simultaneously extend types 'E' and 'D'.
-!!! error TS2320:   Named properties 'a' of types 'E' and 'D' are not identical.
+!!! error TS2320:   Named property 'a' of types 'E' and 'D' are not identical.
     
     class D2 { a: number; }
     class E2 { a: string; }
     interface F2 extends E2, D2 { } // error
               ~~
 !!! error TS2320: Interface 'F2' cannot simultaneously extend types 'E2' and 'D2'.
-!!! error TS2320:   Named properties 'a' of types 'E2' and 'D2' are not identical.
+!!! error TS2320:   Named property 'a' of types 'E2' and 'D2' are not identical.
     

tests/baselines/reference/interfaceWithMultipleBaseTypes.errors.txt

@@ -4,7 +4,7 @@ tests/cases/conformance/interfaces/interfaceDeclarations/interfaceWithMultipleBa
       Types of property 'b' are incompatible.
         Type 'number' is not assignable to type 'string'.
 tests/cases/conformance/interfaces/interfaceDeclarations/interfaceWithMultipleBaseTypes.ts(52,15): error TS2320: Interface 'Derived3<T>' cannot simultaneously extend types 'Base1<number>' and 'Base2<number>'.
-  Named properties 'x' of types 'Base1<number>' and 'Base2<number>' are not identical.
+  Named property 'x' of types 'Base1<number>' and 'Base2<number>' are not identical.
 tests/cases/conformance/interfaces/interfaceDeclarations/interfaceWithMultipleBaseTypes.ts(54,15): error TS2430: Interface 'Derived4<T>' incorrectly extends interface 'Base1<number>'.
   Types of property 'x' are incompatible.
     Type '{ a: T; b: T; }' is not assignable to type '{ a: number; }'.
@@ -86,7 +86,7 @@ tests/cases/conformance/interfaces/interfaceDeclarations/interfaceWithMultipleBa
         interface Derived3<T> extends Base1<number>, Base2<number> { } // error
                   ~~~~~~~~
 !!! error TS2320: Interface 'Derived3<T>' cannot simultaneously extend types 'Base1<number>' and 'Base2<number>'.
-!!! error TS2320:   Named properties 'x' of types 'Base1<number>' and 'Base2<number>' are not identical.
+!!! error TS2320:   Named property 'x' of types 'Base1<number>' and 'Base2<number>' are not identical.
     
         interface Derived4<T> extends Base1<number>, Base2<number> { // error
                   ~~~~~~~~

tests/baselines/reference/letInLetOrConstDeclarations.errors.txt

@@ -1,21 +1,21 @@
-tests/cases/compiler/letInLetOrConstDeclarations.ts(2,9): error TS2476: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
-tests/cases/compiler/letInLetOrConstDeclarations.ts(3,14): error TS2476: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
-tests/cases/compiler/letInLetOrConstDeclarations.ts(6,11): error TS2476: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
+tests/cases/compiler/letInLetOrConstDeclarations.ts(2,9): error TS2480: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
+tests/cases/compiler/letInLetOrConstDeclarations.ts(3,14): error TS2480: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
+tests/cases/compiler/letInLetOrConstDeclarations.ts(6,11): error TS2480: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
 
 
 ==== tests/cases/compiler/letInLetOrConstDeclarations.ts (3 errors) ====
     {
         let let = 1; // should error
             ~~~
-!!! error TS2476: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
+!!! error TS2480: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
         for (let let in []) { } // should error
                  ~~~
-!!! error TS2476: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
+!!! error TS2480: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
     }
     {
         const let = 1; // should error
               ~~~
-!!! error TS2476: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
+!!! error TS2480: 'let' is not allowed to be used as a name in 'let' or 'const' declarations.
     }
     {
         function let() { // should be ok

tests/baselines/reference/mergedInterfacesWithInheritedPrivates3.errors.txt

@@ -1,7 +1,7 @@
 tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithInheritedPrivates3.ts(9,11): error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'.
-  Named properties 'x' of types 'C' and 'C2' are not identical.
+  Named property 'x' of types 'C' and 'C2' are not identical.
 tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithInheritedPrivates3.ts(31,15): error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'.
-  Named properties 'x' of types 'C' and 'C2' are not identical.
+  Named property 'x' of types 'C' and 'C2' are not identical.
 
 
 ==== tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithInheritedPrivates3.ts (2 errors) ====
@@ -16,7 +16,7 @@ tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithInheri
     interface A extends C { // error
               ~
 !!! error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'.
-!!! error TS2320:   Named properties 'x' of types 'C' and 'C2' are not identical.
+!!! error TS2320:   Named property 'x' of types 'C' and 'C2' are not identical.
         y: string;
     }
     
@@ -41,7 +41,7 @@ tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithInheri
         interface A extends C { // error, privates conflict
                   ~
 !!! error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'.
-!!! error TS2320:   Named properties 'x' of types 'C' and 'C2' are not identical.
+!!! error TS2320:   Named property 'x' of types 'C' and 'C2' are not identical.
             y: string;
         }
     

tests/baselines/reference/mergedInterfacesWithMultipleBases4.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithMultipleBases4.ts(19,11): error TS2320: Interface 'A<T>' cannot simultaneously extend types 'C<string>' and 'C<number>'.
-  Named properties 'a' of types 'C<string>' and 'C<number>' are not identical.
+  Named property 'a' of types 'C<string>' and 'C<number>' are not identical.
 
 
 ==== tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithMultipleBases4.ts (1 errors) ====
@@ -24,7 +24,7 @@ tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithMultip
     interface A<T> extends C<string>, C3<string> { // error
               ~
 !!! error TS2320: Interface 'A<T>' cannot simultaneously extend types 'C<string>' and 'C<number>'.
-!!! error TS2320:   Named properties 'a' of types 'C<string>' and 'C<number>' are not identical.
+!!! error TS2320:   Named property 'a' of types 'C<string>' and 'C<number>' are not identical.
         y: T;
     }
     

tests/baselines/reference/multipleBaseInterfaesWithIncompatibleProperties.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/multipleBaseInterfaesWithIncompatibleProperties.ts(6,11): error TS2320: Interface 'C' cannot simultaneously extend types 'A<string>' and 'A<number>'.
-  Named properties 'x' of types 'A<string>' and 'A<number>' are not identical.
+  Named property 'x' of types 'A<string>' and 'A<number>' are not identical.
 
 
 ==== tests/cases/compiler/multipleBaseInterfaesWithIncompatibleProperties.ts (1 errors) ====
@@ -11,5 +11,5 @@ tests/cases/compiler/multipleBaseInterfaesWithIncompatibleProperties.ts(6,11): e
     interface C extends A<string>, A<number> { }
               ~
 !!! error TS2320: Interface 'C' cannot simultaneously extend types 'A<string>' and 'A<number>'.
-!!! error TS2320:   Named properties 'x' of types 'A<string>' and 'A<number>' are not identical.
+!!! error TS2320:   Named property 'x' of types 'A<string>' and 'A<number>' are not identical.
     

tests/baselines/reference/objectCreationOfElementAccessExpression.errors.txt

@@ -1,6 +1,6 @@
-tests/cases/compiler/objectCreationOfElementAccessExpression.ts(53,17): error TS2342: An index expression argument must be of type 'string', 'number', or 'any'.
+tests/cases/compiler/objectCreationOfElementAccessExpression.ts(53,17): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol, or 'any'.
 tests/cases/compiler/objectCreationOfElementAccessExpression.ts(53,63): error TS2348: Value of type 'typeof Cookie' is not callable. Did you mean to include 'new'?
-tests/cases/compiler/objectCreationOfElementAccessExpression.ts(54,33): error TS2342: An index expression argument must be of type 'string', 'number', or 'any'.
+tests/cases/compiler/objectCreationOfElementAccessExpression.ts(54,33): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol, or 'any'.
 tests/cases/compiler/objectCreationOfElementAccessExpression.ts(54,79): error TS2348: Value of type 'typeof Cookie' is not callable. Did you mean to include 'new'?
 
 
@@ -59,12 +59,12 @@ tests/cases/compiler/objectCreationOfElementAccessExpression.ts(54,79): error TS
     // ElementAccessExpressions can only contain one expression.  There should be a parse error here.
     var foods = new PetFood[new IceCream('Mint chocolate chip') , Cookie('Chocolate chip', false) , new Cookie('Peanut butter', true)];
                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', or 'any'.
+!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol, or 'any'.
                                                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2348: Value of type 'typeof Cookie' is not callable. Did you mean to include 'new'?
     var foods2: MonsterFood[] = new PetFood[new IceCream('Mint chocolate chip') , Cookie('Chocolate chip', false) , new Cookie('Peanut butter', true)];
                                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', or 'any'.
+!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol, or 'any'.
                                                                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2348: Value of type 'typeof Cookie' is not callable. Did you mean to include 'new'?
     

tests/baselines/reference/parserComputedPropertyName10.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName10.ts(2,4): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName10.ts(2,4): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName10.ts(2,5): error TS2304: Cannot find name 'e'.
 
 
@@ -6,7 +6,7 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
     class C {
        [e] = 1
        ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         ~
 !!! error TS2304: Cannot find name 'e'.
     }

tests/baselines/reference/parserComputedPropertyName11.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName11.ts(2,4): error TS1168: Computed property names are not allowed in method overloads.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName11.ts(2,4): error TS1168: A computed property name in a method overload must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName11.ts(2,5): error TS2304: Cannot find name 'e'.
 
 
@@ -6,7 +6,7 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
     class C {
        [e]();
        ~~~
-!!! error TS1168: Computed property names are not allowed in method overloads.
+!!! error TS1168: A computed property name in a method overload must directly refer to a built-in symbol.
         ~
 !!! error TS2304: Cannot find name 'e'.
     }

tests/baselines/reference/parserComputedPropertyName13.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName13.ts(1,10): error TS1170: Computed property names are not allowed in type literals.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName13.ts(1,10): error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName13.ts(1,11): error TS2304: Cannot find name 'e'.
 
 
 ==== tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName13.ts (2 errors) ====
     var v: { [e]: number };
              ~~~
-!!! error TS1170: Computed property names are not allowed in type literals.
+!!! error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
               ~
 !!! error TS2304: Cannot find name 'e'.

tests/baselines/reference/parserComputedPropertyName14.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName14.ts(1,10): error TS1170: Computed property names are not allowed in type literals.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName14.ts(1,10): error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName14.ts(1,11): error TS2304: Cannot find name 'e'.
 
 
 ==== tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName14.ts (2 errors) ====
     var v: { [e](): number };
              ~~~
-!!! error TS1170: Computed property names are not allowed in type literals.
+!!! error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
               ~
 !!! error TS2304: Cannot find name 'e'.

tests/baselines/reference/parserComputedPropertyName15.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName15.ts(1,31): error TS1170: Computed property names are not allowed in type literals.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName15.ts(1,31): error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName15.ts(1,32): error TS2304: Cannot find name 'e'.
 
 
 ==== tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName15.ts (2 errors) ====
     var v: { [e: number]: string; [e]: number };
                                   ~~~
-!!! error TS1170: Computed property names are not allowed in type literals.
+!!! error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
                                    ~
 !!! error TS2304: Cannot find name 'e'.

tests/baselines/reference/parserComputedPropertyName18.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName18.ts(1,10): error TS1170: Computed property names are not allowed in type literals.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName18.ts(1,10): error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName18.ts(1,11): error TS2304: Cannot find name 'e'.
 
 
 ==== tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName18.ts (2 errors) ====
     var v: { [e]?(): number };
              ~~~
-!!! error TS1170: Computed property names are not allowed in type literals.
+!!! error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
               ~
 !!! error TS2304: Cannot find name 'e'.

tests/baselines/reference/parserComputedPropertyName19.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName19.ts(1,10): error TS1170: Computed property names are not allowed in type literals.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName19.ts(1,10): error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName19.ts(1,11): error TS2304: Cannot find name 'e'.
 
 
 ==== tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName19.ts (2 errors) ====
     var v: { [e]? };
              ~~~
-!!! error TS1170: Computed property names are not allowed in type literals.
+!!! error TS1170: A computed property name in a type literal must directly refer to a built-in symbol.
               ~
 !!! error TS2304: Cannot find name 'e'.

tests/baselines/reference/parserComputedPropertyName20.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName20.ts(2,5): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName20.ts(2,5): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName20.ts(2,6): error TS2304: Cannot find name 'e'.
 
 
@@ -6,7 +6,7 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
     interface I {
         [e](): number 
         ~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'e'.
     }

tests/baselines/reference/parserComputedPropertyName21.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName21.ts(2,5): error TS1169: Computed property names are not allowed in interfaces.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName21.ts(2,5): error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName21.ts(2,6): error TS2304: Cannot find name 'e'.
 
 
@@ -6,7 +6,7 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
     interface I {
         [e]: number 
         ~~~
-!!! error TS1169: Computed property names are not allowed in interfaces.
+!!! error TS1169: A computed property name in an interface must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'e'.
     }

tests/baselines/reference/parserComputedPropertyName22.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName22.ts(2,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName22.ts(2,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName22.ts(2,6): error TS2304: Cannot find name 'e'.
 
 
@@ -6,7 +6,7 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
     declare class C {
         [e]: number 
         ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'e'.
     }

tests/baselines/reference/parserComputedPropertyName25.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName25.ts(3,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName25.ts(3,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName25.ts(3,6): error TS2304: Cannot find name 'e'.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName25.ts(4,6): error TS2304: Cannot find name 'e2'.
 
@@ -8,7 +8,7 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
         // No ASI
         [e] = 0
         ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'e'.
         [e2] = 1

tests/baselines/reference/parserComputedPropertyName28.errors.txt

@@ -1,6 +1,6 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName28.ts(2,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName28.ts(2,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName28.ts(2,6): error TS2304: Cannot find name 'e'.
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName28.ts(3,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName28.ts(3,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName28.ts(3,6): error TS2304: Cannot find name 'e2'.
 
 
@@ -8,12 +8,12 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
     class C {
         [e]: number = 0;
         ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'e'.
         [e2]: number
         ~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~~
 !!! error TS2304: Cannot find name 'e2'.
     }

tests/baselines/reference/parserComputedPropertyName29.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName29.ts(3,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName29.ts(3,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName29.ts(3,6): error TS2304: Cannot find name 'e'.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName29.ts(3,11): error TS2304: Cannot find name 'id'.
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName29.ts(4,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName29.ts(4,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName29.ts(4,6): error TS2304: Cannot find name 'e2'.
 
 
@@ -10,14 +10,14 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
         // yes ASI
         [e] = id++
         ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'e'.
               ~~
 !!! error TS2304: Cannot find name 'id'.
         [e2]: number
         ~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~~
 !!! error TS2304: Cannot find name 'e2'.
     }

tests/baselines/reference/parserComputedPropertyName31.errors.txt

@@ -1,6 +1,6 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName31.ts(3,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName31.ts(3,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName31.ts(3,6): error TS2304: Cannot find name 'e'.
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName31.ts(4,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName31.ts(4,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName31.ts(4,6): error TS2304: Cannot find name 'e2'.
 
 
@@ -9,12 +9,12 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
         // yes ASI
         [e]: number
         ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'e'.
         [e2]: number
         ~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~~
 !!! error TS2304: Cannot find name 'e2'.
     }

tests/baselines/reference/parserComputedPropertyName32.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName32.ts(2,5): error TS1165: Computed property names are not allowed in an ambient context.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName32.ts(2,5): error TS1165: A computed property name in an ambient context must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName32.ts(2,6): error TS2304: Cannot find name 'e'.
 
 
@@ -6,7 +6,7 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
     declare class C {
         [e](): number 
         ~~~
-!!! error TS1165: Computed property names are not allowed in an ambient context.
+!!! error TS1165: A computed property name in an ambient context must directly refer to a built-in symbol.
          ~
 !!! error TS2304: Cannot find name 'e'.
     }

tests/baselines/reference/parserComputedPropertyName36.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName36.ts(2,5): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName36.ts(2,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName36.ts(2,6): error TS2304: Cannot find name 'public'.
 
 
@@ -6,7 +6,7 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
     class C {
         [public ]: string;
         ~~~~~~~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
          ~~~~~~
 !!! error TS2304: Cannot find name 'public'.
     }

tests/baselines/reference/parserComputedPropertyName41.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName41.ts(2,5): error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName41.ts(2,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 
 
 ==== tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName41.ts (1 errors) ====
     var v = {
         [0 in []]: true
         ~~~~~~~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', or 'any'.
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
     }

tests/baselines/reference/parserComputedPropertyName7.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName7.ts(2,4): error TS1166: Computed property names are not allowed in class property declarations.
+tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName7.ts(2,4): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName7.ts(2,5): error TS2304: Cannot find name 'e'.
 
 
@@ -6,7 +6,7 @@ tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedP
     class C {
        [e]
        ~~~
-!!! error TS1166: Computed property names are not allowed in class property declarations.
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
         ~
 !!! error TS2304: Cannot find name 'e'.
     }