Fix microsoft#2929: relax the check for export= in ES6 if it is resulting from an ambient declaration

Author: mhegazy

src/compiler/checker.ts

@@ -10689,7 +10689,7 @@ module ts {
  }
  checkExternalModuleExports(container);
 
- if (node.isExportEquals) {
+ if (node.isExportEquals && !isInAmbientContext(node)) {
  if (languageVersion >= ScriptTarget.ES6) {
  // export assignment is deprecated in es6 or above
  grammarErrorOnNode(node, Diagnostics.Export_assignment_cannot_be_used_when_targeting_ECMAScript_6_or_higher_Consider_using_export_default_instead);

tests/baselines/reference/es6ExportAssignment2.errors.txt

@@ -0,0 +1,13 @@
+tests/cases/compiler/a.ts(3,1): error TS1203: Export assignment cannot be used when targeting ECMAScript 6 or higher. Consider using 'export default' instead.
+
+
+==== tests/cases/compiler/a.ts (1 errors) ====
+ 
+ var a = 10;
+ export = a; // Error: export = not allowed in ES6
+ ~~~~~~~~~~~
+!!! error TS1203: Export assignment cannot be used when targeting ECMAScript 6 or higher. Consider using 'export default' instead.
+ 
+==== tests/cases/compiler/b.ts (0 errors) ====
+ import * as a from "a";
+ 

tests/baselines/reference/es6ExportAssignment2.js

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/es6ExportAssignment2.ts] ////
+
+//// [a.ts]
+
+var a = 10;
+export = a; // Error: export = not allowed in ES6
+
+//// [b.ts]
+import * as a from "a";
+
+
+//// [a.js]
+var a = 10;
+//// [b.js]

tests/baselines/reference/es6ExportAssignment3.js

@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/es6ExportAssignment3.ts] ////
+
+//// [a.d.ts]
+
+declare var a: number;
+export = a; // OK, in ambient context
+
+//// [b.ts]
+import * as a from "a";
+
+
+//// [b.js]

tests/baselines/reference/es6ExportAssignment3.symbols

@@ -0,0 +1,12 @@
+=== tests/cases/compiler/a.d.ts ===
+
+declare var a: number;
+>a : Symbol(a, Decl(a.d.ts, 1, 11))
+
+export = a; // OK, in ambient context
+>a : Symbol(a, Decl(a.d.ts, 1, 11))
+
+=== tests/cases/compiler/b.ts ===
+import * as a from "a";
+>a : Symbol(a, Decl(b.ts, 0, 6))
+

tests/baselines/reference/es6ExportAssignment3.types

@@ -0,0 +1,12 @@
+=== tests/cases/compiler/a.d.ts ===
+
+declare var a: number;
+>a : number
+
+export = a; // OK, in ambient context
+>a : number
+
+=== tests/cases/compiler/b.ts ===
+import * as a from "a";
+>a : number
+

tests/baselines/reference/es6ExportAssignment4.js

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/es6ExportAssignment4.ts] ////
+
+//// [modules.d.ts]
+
+declare module "a" {
+ var a: number;
+ export = a; // OK, in ambient context
+}
+
+//// [b.ts]
+import * as a from "a";
+
+
+//// [b.js]

tests/baselines/reference/es6ExportAssignment4.symbols

@@ -0,0 +1,14 @@
+=== tests/cases/compiler/modules.d.ts ===
+
+declare module "a" {
+ var a: number;
+>a : Symbol(a, Decl(modules.d.ts, 2, 7))
+
+ export = a; // OK, in ambient context
+>a : Symbol(a, Decl(modules.d.ts, 2, 7))
+}
+
+=== tests/cases/compiler/b.ts ===
+import * as a from "a";
+>a : Symbol(a, Decl(b.ts, 0, 6))
+

tests/baselines/reference/es6ExportAssignment4.types

@@ -0,0 +1,14 @@
+=== tests/cases/compiler/modules.d.ts ===
+
+declare module "a" {
+ var a: number;
+>a : number
+
+ export = a; // OK, in ambient context
+>a : number
+}
+
+=== tests/cases/compiler/b.ts ===
+import * as a from "a";
+>a : number
+

tests/baselines/reference/systemExportAssignment.js

@@ -0,0 +1,19 @@
+//// [tests/cases/compiler/systemExportAssignment.ts] ////
+
+//// [a.d.ts]
+
+declare var a: number;
+export = a; // OK, in ambient context
+
+//// [b.ts]
+import * as a from "a";
+
+
+//// [b.js]
+System.register([], function(exports_1) {
+ return {
+ setters:[],
+ execute: function() {
+ }
+ }
+});