Fix binding well-known symbols by element access

Author: andrewbranch

src/compiler/types.ts

@@ -819,7 +819,14 @@ namespace ts {
 
     export type PropertyName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName;
 
-    export type DeclarationName = Identifier | StringLiteralLike | NumericLiteral | ComputedPropertyName | ElementAccessExpression | BindingPattern;
+    export type DeclarationName =
+        | Identifier
+        | StringLiteralLike
+        | NumericLiteral
+        | ComputedPropertyName
+        | ElementAccessExpression
+        | BindingPattern
+        | WellKnownSymbolExpression;
 
     export interface Declaration extends Node {
         _declarationBrand: any;
@@ -1884,13 +1891,17 @@ namespace ts {
         | CallChainRoot
         ;
 
+    /** @internal */
+    export interface WellKnownSymbolExpression extends PropertyAccessExpression {
+        expression: Identifier & { escapedText: "Symbol" };
+    }
     /** @internal */
     export type BindableObjectDefinePropertyCall = CallExpression & { arguments: { 0: BindableStaticNameExpression, 1: StringLiteralLike | NumericLiteral, 2: ObjectLiteralExpression } };
     /** @internal */
     export type BindableStaticNameExpression = EntityNameExpression | BindableStaticElementAccessExpression;
     /** @internal */
     export type LiteralLikeElementAccessExpression = ElementAccessExpression & Declaration & {
-        argumentExpression: StringLiteralLike | NumericLiteral;
+        argumentExpression: StringLiteralLike | NumericLiteral | WellKnownSymbolExpression;
     };
     /** @internal */
     export type BindableStaticElementAccessExpression = LiteralLikeElementAccessExpression & {

src/compiler/utilities.ts

@@ -2068,7 +2068,9 @@ namespace ts {
     }
 
     export function isLiteralLikeElementAccess(node: Node): node is LiteralLikeElementAccessExpression {
-        return isElementAccessExpression(node) && isStringOrNumericLiteralLike(node.argumentExpression);
+        return isElementAccessExpression(node) && (
+            isStringOrNumericLiteralLike(node.argumentExpression) ||
+            isWellKnownSymbolSyntactically(node.argumentExpression));
     }
 
     export function isBindableStaticAccessExpression(node: Node, excludeThisKeyword?: boolean): node is BindableStaticAccessExpression {
@@ -2898,7 +2900,7 @@ namespace ts {
      *    Symbol.name
      * where Symbol is literally the word "Symbol", and name is any identifierName
      */
-    export function isWellKnownSymbolSyntactically(node: Expression): boolean {
+    export function isWellKnownSymbolSyntactically(node: Expression): node is WellKnownSymbolExpression {
         return isPropertyAccessExpression(node) && isESSymbolIdentifier(node.expression);
     }
 

src/services/navigationBar.ts

@@ -136,7 +136,7 @@ namespace ts.NavigationBar {
         for (let i = 0; i < depth; i++) endNode();
     }
     function startNestedNodes(targetNode: Node, entityName: BindableStaticNameExpression) {
-        const names: PropertyNameLiteral[] = [];
+        const names: (PropertyNameLiteral | WellKnownSymbolExpression)[] = [];
         while (!isPropertyNameLiteral(entityName)) {
             const name = getNameOrArgument(entityName);
             const nameText = getElementOrPropertyAccessName(entityName);
@@ -334,7 +334,7 @@ namespace ts.NavigationBar {
                             assignmentTarget;
 
                         let depth = 0;
-                        let className: PropertyNameLiteral;
+                        let className: PropertyNameLiteral | WellKnownSymbolExpression;
                         // If we see a prototype assignment, start tracking the target as a class
                         // This is only done for simple classes not nested assignments.
                         if (isIdentifier(prototypeAccess.expression)) {

tests/cases/compiler/wellKnownSymbolExpando.ts

@@ -0,0 +1,5 @@
+// @noEmit: true
+// @target: esnext
+
+function f() {}
+f[Symbol.iterator] = function() {}