Added es5 conformance tests for async arrow functions, add error for referencing 'arguments' in a generator.

Author: rbuckton

src/compiler/checker.ts

@@ -8162,10 +8162,13 @@ namespace ts {
             // can explicitly bound arguments objects
             if (symbol === argumentsSymbol) {
                 const container = getContainingFunction(node);
-                if (container.kind === SyntaxKind.ArrowFunction) {
-                    if (languageVersion < ScriptTarget.ES6) {
+                if (languageVersion < ScriptTarget.ES6) {
+                    if (container.kind === SyntaxKind.ArrowFunction) {
                         error(node, Diagnostics.The_arguments_object_cannot_be_referenced_in_an_arrow_function_in_ES3_and_ES5_Consider_using_a_standard_function_expression);
                     }
+                    else if (hasModifier(container, ModifierFlags.Async)) {
+                        error(node, Diagnostics.The_arguments_object_cannot_be_referenced_in_an_async_function_or_method_in_ES3_and_ES5_Consider_using_a_standard_function_or_method);
+                    }
                 }
 
                 if (node.flags & NodeFlags.AwaitContext) {

src/compiler/diagnosticMessages.json

@@ -1695,7 +1695,7 @@
         "category": "Error",
         "code": 2521
     },
-    "The 'arguments' object cannot be referenced in an async arrow function. Consider using a standard async function expression.": {
+    "The 'arguments' object cannot be referenced in an async function or method in ES3 and ES5. Consider using a standard function or method.": {
         "category": "Error",
         "code": 2522
     },

tests/baselines/reference/arrowFunctionWithParameterNameAsync_es5.js

@@ -0,0 +1,6 @@
+//// [arrowFunctionWithParameterNameAsync_es5.ts]
+
+const x = async => async;
+
+//// [arrowFunctionWithParameterNameAsync_es5.js]
+var x = function (async) { return async; };

tests/baselines/reference/arrowFunctionWithParameterNameAsync_es5.symbols

@@ -0,0 +1,7 @@
+=== tests/cases/conformance/async/es5/asyncArrowFunction/arrowFunctionWithParameterNameAsync_es5.ts ===
+
+const x = async => async;
+>x : Symbol(x, Decl(arrowFunctionWithParameterNameAsync_es5.ts, 1, 5))
+>async : Symbol(async, Decl(arrowFunctionWithParameterNameAsync_es5.ts, 1, 9))
+>async : Symbol(async, Decl(arrowFunctionWithParameterNameAsync_es5.ts, 1, 9))
+

tests/baselines/reference/arrowFunctionWithParameterNameAsync_es5.types

@@ -0,0 +1,8 @@
+=== tests/cases/conformance/async/es5/asyncArrowFunction/arrowFunctionWithParameterNameAsync_es5.ts ===
+
+const x = async => async;
+>x : (async: any) => any
+>async => async : (async: any) => any
+>async : any
+>async : any
+

tests/baselines/reference/asyncArrowFunction10_es5.errors.txt

@@ -0,0 +1,12 @@
+tests/cases/conformance/async/es5/asyncArrowFunction/asyncArrowFunction10_es5.ts(4,11): error TS2304: Cannot find name 'await'.
+
+
+==== tests/cases/conformance/async/es5/asyncArrowFunction/asyncArrowFunction10_es5.ts (1 errors) ====
+    
+    var foo = async (): Promise<void> => {
+       // Legal to use 'await' in a type context.
+       var v: await;
+              ~~~~~
+!!! error TS2304: Cannot find name 'await'.
+    }
+    

tests/baselines/reference/asyncArrowFunction10_es5.js

@@ -0,0 +1,16 @@
+//// [asyncArrowFunction10_es5.ts]
+
+var foo = async (): Promise<void> => {
+   // Legal to use 'await' in a type context.
+   var v: await;
+}
+
+
+//// [asyncArrowFunction10_es5.js]
+var _this = this;
+var foo = function () { return __awaiter(_this, void 0, void 0, function () {
+    var v;
+    return __generator(this, function (_a) {
+        return [2 /*return*/];
+    });
+}); };

tests/baselines/reference/asyncArrowFunction1_es5.js

@@ -0,0 +1,12 @@
+//// [asyncArrowFunction1_es5.ts]
+
+var foo = async (): Promise<void> => {
+};
+
+//// [asyncArrowFunction1_es5.js]
+var _this = this;
+var foo = function () { return __awaiter(_this, void 0, void 0, function () {
+    return __generator(this, function (_a) {
+        return [2 /*return*/];
+    });
+}); };

tests/baselines/reference/asyncArrowFunction1_es5.symbols

@@ -0,0 +1,7 @@
+=== tests/cases/conformance/async/es5/asyncArrowFunction/asyncArrowFunction1_es5.ts ===
+
+var foo = async (): Promise<void> => {
+>foo : Symbol(foo, Decl(asyncArrowFunction1_es5.ts, 1, 3))
+>Promise : Symbol(Promise, Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --))
+
+};

tests/baselines/reference/asyncArrowFunction1_es5.types

@@ -0,0 +1,8 @@
+=== tests/cases/conformance/async/es5/asyncArrowFunction/asyncArrowFunction1_es5.ts ===
+
+var foo = async (): Promise<void> => {
+>foo : () => Promise<void>
+>async (): Promise<void> => {} : () => Promise<void>
+>Promise : Promise<T>
+
+};