diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_8/genexps/regress-683738.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_8/genexps/regress-683738.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,71 @@
+/* -*- 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 = 683738;
+var summary = 'return with argument and lazy generator detection';
+var actual = '';
+var expect = '';
+
+//-----------------------------------------------------------------------------
+test();
+//-----------------------------------------------------------------------------
+
+function test()
+{
+  enterFunc ('test');
+  printBugNumber(BUGNUMBER);
+  printStatus (summary);
+
+  expect = "generator function foo returns a value";
+  try
+  {
+    actual = 'No Error';
+    eval("function foo(x) { if (x) { return this; } else { yield 3; } }");
+  }
+  catch(ex)
+  {
+    actual = ex.message;
+  }
+  reportCompare(expect, actual, summary + ": 1");
+
+  expect = "generator function foo returns a value";
+  try
+  {
+    actual = 'No Error';
+    eval("function foo(x) { if (x) { yield 3; } else { return this; } }");
+  }
+  catch(ex)
+  {
+    actual = ex.message;
+  }
+  reportCompare(expect, actual, summary + ": 2");
+
+  expect = "generator function foo returns a value";
+  try
+  {
+    actual = 'No Error';
+    eval("function foo(x) { if (x) { return this; } else { (yield 3); } }");
+  }
+  catch(ex)
+  {
+    actual = ex.message;
+  }
+  reportCompare(expect, actual, summary + ": 3");
+
+  expect = "generator function foo returns a value";
+  try
+  {
+    actual = 'No Error';
+    eval("function foo(x) { if (x) { (yield 3); } else { return this; } }");
+  }
+  catch(ex)
+  {
+    actual = ex.message;
+  }
+  reportCompare(expect, actual, summary + ": 4");
+
+}