diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_6/extensions/regress-457521.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_6/extensions/regress-457521.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,24 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//-----------------------------------------------------------------------------
+var BUGNUMBER = 457521;
+var summary = 'Do not crash @ js_DecompileValueGenerator';
+var actual = '';
+var expect = '';
+
+printBugNumber(BUGNUMBER);
+printStatus (summary);
+
+try
+{
+  this.__defineSetter__("x", [,,,].map);
+  this.watch("x", (new Function("var y, eval")));
+  x = true;
+}
+catch(ex)
+{
+}
+reportCompare(expect, actual, summary);