diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_8_5/regress/regress-643222.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_8_5/regress/regress-643222.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,12 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/licenses/publicdomain/
+ */
+
+/* This shouldn't trigger an assertion. */
+(function () {
+    eval("var x=delete(x)")
+})();
+
+reportCompare(0, 0, "ok");