diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_5/Regress/regress-398609.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_5/Regress/regress-398609.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,39 @@
+/* -*- 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 = 398609;
+var summary = 'Test regression from bug 398609';
+var actual = 'No Error';
+var expect = 'No Error';
+
+
+//-----------------------------------------------------------------------------
+test();
+//-----------------------------------------------------------------------------
+
+function test()
+{
+  enterFunc ('test');
+  printBugNumber(BUGNUMBER);
+  printStatus (summary);
+ 
+  function f(m) {
+    m = m || Math;
+    return x();
+
+    function x() {
+      return m.sin(0);
+    }
+  };
+
+  var r = f();
+  if (r !== Math.sin(0))
+    throw "Unexpected result";
+
+  reportCompare(expect, actual, summary);
+
+  exitFunc ('test');
+}