When creating synthetic default symbol set parent as module symbol (microsoft#41282)

Fixes microsoft#40684

Author: sheetalkamat

src/compiler/checker.ts

@@ -28499,6 +28499,7 @@ namespace ts {
                     if (hasSyntheticDefault) {
                         const memberTable = createSymbolTable();
                         const newSymbol = createSymbol(SymbolFlags.Alias, InternalSymbolName.Default);
+                        newSymbol.parent = originalSymbol;
                         newSymbol.nameType = getLiteralType("default");
                         newSymbol.target = resolveSymbol(symbol);
                         memberTable.set(InternalSymbolName.Default, newSymbol);

tests/cases/fourslash/exportEqualNamespaceClassESModuleInterop.ts

@@ -0,0 +1,28 @@
+/// <reference path='fourslash.ts'/>
+
+// @esModuleInterop: true
+// @moduleResolution: node
+// @target: es2015
+// @module: esnext
+
+// @Filename: /node_modules/@bar/foo/index.d.ts
+//// export = Foo;
+//// declare class Foo {}
+//// declare namespace Foo {}  // class/namespace declaration causes the issue
+
+// @Filename: /node_modules/foo/index.d.ts
+//// import * as Foo from "@bar/foo";
+//// export = Foo;
+
+// @Filename: /index.ts
+//// import Foo from "foo";
+//// /**/
+
+goTo.file("/index.ts");
+verify.completions({
+    marker: "",
+    includes: ["Foo"],
+    preferences: {
+        includeCompletionsForModuleExports: true
+    }
+});