[es6] generate rest parameters correctly for subclass constructors

test/mjsunit/harmony/rest-params.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-rest-parameters
+// Flags: --harmony-rest-parameters --harmony-classes
 
 (function testRestIndex() {
   assertEquals(5, (function(...args) { return args.length; })(1,2,3,4,5));
   assertEquals(4, (function(a, ...args) { return args.length; })(1,2,3,4,5));
   assertEquals(3, (function(a, b, ...args) { return args.length; })(1,2,3,4,5));
   assertEquals(2, (function(a, b, c, ...args) {
                       return args.length; })(1,2,3,4,5));
   assertEquals(1, (function(a, b, c, d, ...args) {
                       return args.length; })(1,2,3,4,5));
   assertEquals(0, (function(a, b, c, d, e, ...args) {
@@ skipping 157 matching lines @@
   var fn = (a, b, ...c) => c;
   assertEquals([], fn());
   assertEquals([], fn(1, 2));
   assertEquals([3], fn(1, 2, 3));
   assertEquals([3, 4], fn(1, 2, 3, 4));
   assertEquals([3, 4, 5], fn(1, 2, 3, 4, 5));
   assertThrows("var x = ...y => y;", SyntaxError);
   assertEquals([], ((...args) => args)());
   assertEquals([1,2,3], ((...args) => args)(1,2,3));
 })();*/
+
+
+(function testRestParamsWithNewTarget() {
+  "use strict";
+  class Base {
+    constructor(...a) { this.base = a; }

[Dmitry Lomov (no reviews), 2015/03/20 08:32:46]

Please add tests that validate 'arguments'  behavior in these cases.

[caitp (gmail), 2015/03/20 13:28:40]

You mean, assert that the arguments elements are identical to the rest parameter
elements? Or the restriction on "caller" / "callee" etc

--- added more to the test for the first part

[Dmitry Lomov (no reviews), 2015/03/20 13:45:14]

First part is what I meant - since you indirectly modified code related to
'arguments' object buiilding

+  }
+  class Child extends Base {
+    constructor(...b) { super(1, 2, 3); this.child = b; }
+  }
+
+  var c = new Child(1, 2, 3);
+  assertEquals([1, 2, 3], c.child);
+  assertEquals([1, 2, 3], c.base);
+})();