diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_5/Regress/regress-317533.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_5/Regress/regress-317533.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,52 @@
+/* -*- 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 = 317533;
+var summary = 'improve function does not always return a value warnings';
+var actual = '';
+var expect = 'TypeError: anonymous function does not always return a value';
+
+printBugNumber(BUGNUMBER);
+printStatus (summary);
+ 
+var code;
+
+if (!options().match(/strict/))
+{
+  options('strict');
+}
+if (!options().match(/werror/))
+{
+  options('werror');
+}
+
+try
+{
+  actual = '';
+  code = "(function(x){ if(x) return x; })";
+  print(code);
+  eval(code);
+}
+catch(ex)
+{
+  actual = ex + '';
+}
+
+reportCompare(expect, actual, summary);
+
+try
+{
+  actual = '';
+  code = "(function(x){ if(x) return x; ;})";
+  print(code);
+  eval(code);
+}
+catch(ex)
+{
+  actual = ex + '';
+}
+
+reportCompare(expect, actual, summary);