[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;
+      assertEquals(arguments.length, a.length);
+      var args = [];
+      for (var i = 0; i < arguments.length; ++i) {
+        args.push(arguments[i]);
+      }
+      assertEquals(args, a);
+    }
+  }
+  class Child extends Base {
+    constructor(...b) {
+      super(1, 2, 3);
+      this.child = b;
+      assertEquals(arguments.length, b.length);
+      var args = [];
+      for (var i = 0; i < arguments.length; ++i) {
+        args.push(arguments[i]);
+      }
+      assertEquals(args, b);
+    }
+  }
+
+  var c = new Child(1, 2, 3);
+  assertEquals([1, 2, 3], c.child);
+  assertEquals([1, 2, 3], c.base);
+})();