Support rest parameters in arrow functions

test/mjsunit/harmony/rest-params-lazy-parsing.js

Index: test/mjsunit/harmony/rest-params-lazy-parsing.js
diff --git a/test/mjsunit/harmony/rest-params-lazy-parsing.js b/test/mjsunit/harmony/rest-params-lazy-parsing.js
index ba8e3008b959c01bfbc6229413b9cbbf00642263..b50a990f5c5aaa0a0e32cba9c6c4f0027e4c59b6 100644
--- a/test/mjsunit/harmony/rest-params-lazy-parsing.js
+++ b/test/mjsunit/harmony/rest-params-lazy-parsing.js
@@ -2,7 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --harmony-rest-parameters --min-preparse-length=0
+// Flags: --harmony-rest-parameters --harmony-arrow-functions
+// Flags: --min-preparse-length=0
 
 function variadic(co, ...values) {
   var sum = 0;
@@ -12,6 +13,21 @@ function variadic(co, ...values) {
   return sum;
 }
 
+var arrowVariadic = (co, ...values) => {
+  var sum = 0;
+  while (values.length) {
+    sum += co * values.pop();
+  }
+  return sum;
+}
+
+assertEquals(1, variadic.length);
+assertEquals(1, arrowVariadic.length);
+
 assertEquals(90, variadic(2, 1, 2, 3, 4, 5, 6, 7, 8, 9));
 assertEquals(74, variadic(2, 1, 2, 3, 4, 5, 6, 7, 9));
 assertEquals(110, variadic(2, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
+
+assertEquals(90, arrowVariadic(2, 1, 2, 3, 4, 5, 6, 7, 8, 9));
+assertEquals(74, arrowVariadic(2, 1, 2, 3, 4, 5, 6, 7, 9));
+assertEquals(110, arrowVariadic(2, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10));