Improve strictness of Annex B 3.3 for generators and async functions

test/mjsunit/harmony/sloppy-legacy-duplicate-generators.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --no-harmony-restrictive-generators
+
+// In legacy mode, generators get sloppy-mode block-scoped function hoisting
+
+// Hoisting to the global scope
+
+{
+  function* foo() {}
+  assertEquals('function', typeof foo);
+}
+//assertEquals('function', typeof foo);
+
+// Hoisting within a function scope
+(function() {
+  { function* bar() {} }
+  assertEquals('function', typeof bar);
+})();
+
+// Lexical shadowing allowed; hoisting happens
+(function() {
+  function* x() { yield 1; }
+  { function* x() { yield 2 } }
+  assertEquals(2, x().next().value);
+})();
+
+// Duplicates allowed
+(function() {
+  function* y() { yield 1; }
+  function* y() { yield 2 }
+  assertEquals(2, y().next().value);
+})();
+
+// Functions and generators may duplicate each other
+(function() {
+  function* z() { yield 1; }
+  function z() { return 2 }
+  assertEquals(2, z());
+
+  function a() { return 1; }
+  function* a() { yield 2 }
+  assertEquals(2, a().next().value);
+})();
+
+// In strict mode, none of this happens
+
+(function() {
+  'use strict';
+
+  { function* bar() {} }
+  assertEquals('undefined', typeof bar);
+
+  // Lexical shadowing allowed; hoisting happens
+  function* x() { yield 1; }
+  { function* x() { yield 2 } }
+  assertEquals(1, x().next().value);
+})();