Reland of Ship ES2015 sloppy-mode function hoisting, let, class

test/mjsunit/es6/block-let-contextual-sloppy.js

+// Copyright 2015 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: --harmony-sloppy --harmony-sloppy-let --harmony-destructuring-bind
+
+// let is usable as a variable with var or legacy const, not let or ES6 const
+
+(function (){
+  assertEquals(undefined, let);
+
+  var let;
+
+  let = 5;
+  assertEquals(5, let);
+
+  (function() { var let = 1; assertEquals(1, let); })();
+  assertEquals(5, let);
+})();
+
+assertThrows(function() { return let; }, ReferenceError);
+
+(function() {
+   var let, sum = 0;
+   for (let in [1, 2, 3, 4]) sum += Number(let);
+   assertEquals(6, sum);
+
+   (function() { for (var let of [4, 5]) sum += let; })();
+   assertEquals(15, sum);
+
+   (function() { for (var let in [6]) sum += Number([6][let]); })();
+   assertEquals(21, sum);
+
+   for (let = 7; let < 8; let++) sum += let;
+   assertEquals(28, sum);
+   assertEquals(8, let);
+
+   (function() { for (var let = 8; let < 9; let++) sum += let; })();
+   assertEquals(36, sum);
+   assertEquals(8, let);
+})();
+
+assertThrows(function() { return let; }, ReferenceError);
+
+(function () {
+  let obj = {};
+  var {let} = {let() { return obj; }};
+  let().x = 1;
+  assertEquals(1, obj.x);
+})();
+
+(function () {
+  let obj = {};
+  const [let] = [function() { return obj; }];
+  let().x = 1;
+  assertEquals(1, obj.x);
+})();
+
+(function() {
+  function let() {
+    return 1;
+  }
+  assertEquals(1, let());
+})()
+
+assertThrows('for (let of []) {}', SyntaxError);