new file mode 100644
--- /dev/null
+++ b/js/src/xpconnect/tests/unit/bug451678_subscript.js
@@ -0,0 +1,2 @@
+var tags = [];
+function makeTags() {}

new file mode 100644
--- /dev/null
+++ b/js/src/xpconnect/tests/unit/test_bug451678.js
@@ -0,0 +1,52 @@
+/*
+ * ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Mozilla code.
+ *
+ * The Initial Developer of the Original Code is
+ * Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2008
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *    Ted Mielczarek <ted.mielczarek@gmail.com> (original author)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+
+function run_test() {
+  var file = do_get_file("js/src/xpconnect/tests/unit/bug451678_subscript.js");
+  var ios = Cc["@mozilla.org/network/io-service;1"]
+              .getService(Ci.nsIIOService);
+  var uri = ios.newFileURI(file);
+  var scriptLoader = Cc["@mozilla.org/moz/jssubscript-loader;1"]
+                       .getService(Ci.mozIJSSubScriptLoader);
+  var srvScope = {};
+  scriptLoader.loadSubScript(uri.spec, srvScope);
+  do_check_true('makeTags' in srvScope && srvScope.makeTags instanceof Function);
+}