harmony-scoping: Allow 'const' iteration variables in strict mode.

test/mjsunit/regress/regress-2506.js

+// Copyright 2014 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-scoping
+
+'use strict';
+
+// Top-level code

[rossberg, 2014/10/23 10:41:28]

Actually, on second though, we should have more tests. In particular, test that

- fresh bindings are correctly created for each iteration of the loop (using
closures),

- assignment is properly rejected (in strict and sloppy mode).

These are probably not regression tests, but should extend the respective tests
we already have for 'for-let-in/of'.

[rossberg, 2014/10/23 10:47:11]

Ah sorry, please ignore.

+let s = 0;
+let f = [undefined, undefined, undefined]
+for (const x of [1,2,3]) {
+  s += x;
+  f[x-1] = function() { return x; }
+}
+assertEquals(6, s);
+assertEquals(1, f[0]());
+assertEquals(2, f[1]());
+assertEquals(3, f[2]());
+
+let x = 1;
+s = 0;
+for (const x of [x, x+1, x+2]) {
+  s += x;
+}
+assertEquals(6, s);
+
+s = 0;
+var q = 1;
+for (const q of [q, q+1, q+2]) {
+  s += q;
+}
+assertEquals(6, s);
+
+let z = 1;
+s = 0;
+for (const x = 1; z < 2; z++) {
+  s += x + z;
+}
+assertEquals(2, s);
+
+
+s = "";
+for (const x in [1,2,3]) {
+  s += x;
+}
+assertEquals("012", s);
+
+assertThrows(function() { for(const x in [1,2,3]) { x++ } }, SyntaxError);
+
+// Function scope
+(function() {
+  let s = 0;
+  for (const x of [1,2,3]) {
+    s += x;
+  }
+  assertEquals(6, s);
+
+  let x = 1;
+  s = 0;
+  for (const x of [x, x+1, x+2]) {
+    s += x;
+  }
+  assertEquals(6, s);
+
+  s = 0;
+  var q = 1;
+  for (const q of [q, q+1, q+2]) {
+    s += q;
+  }
+  assertEquals(6, s);
+
+  s = "";
+  for (const x in [1,2,3]) {
+    s += x;
+  }
+  assertEquals("012", s);
+}());