diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_8/genexps/regress-347739.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_8/genexps/regress-347739.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,51 @@
+/* -*- 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 = 347739;
+var summary = 'generator_instance.close readonly and immune';
+var actual = '';
+var expect = '';
+
+
+//-----------------------------------------------------------------------------
+test();
+//-----------------------------------------------------------------------------
+
+function test()
+{
+  enterFunc ('test');
+  printBugNumber(BUGNUMBER);
+  printStatus (summary);
+
+  function gen_test(test_index)
+  {
+    try {
+      yield 1;
+    } finally {
+      actual += "Inside finally: "+test_index + ' ';
+    }
+  }
+
+  actual = '';
+  expect = 'Inside finally: 1 Inside finally: 2 ';
+
+  var iter1 = gen_test(1);
+  var close = iter1.close;
+  iter1.close = null;
+  delete iter1.close;
+  iter1.next();
+  iter1.close();
+
+  var iter2 = gen_test(2);
+  for (i in iter2) {
+    iter2.close = null;
+    delete iter2.close;
+  }
+
+  reportCompare(expect, actual, summary + ': 2');
+
+  exitFunc ('test');
+}