diff -r 000000000000 -r 6474c204b198 js/src/tests/ecma_5/Global/delete-global-NaN-property.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/ecma_5/Global/delete-global-NaN-property.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,32 @@
+// Any copyright is dedicated to the Public Domain.
+// http://creativecommons.org/licenses/publicdomain/
+"use strict"
+
+//-----------------------------------------------------------------------------
+var BUGNUMBER = 649570;
+var summary = "|delete window.NaN| should throw a TypeError";
+
+print(BUGNUMBER + ": " + summary);
+
+/**************
+ * BEGIN TEST *
+ **************/
+
+var g = this, v = false;
+try
+{
+  delete this.NaN;
+  throw new Error("no exception thrown");
+}
+catch (e)
+{
+  assertEq(e instanceof TypeError, true,
+           "Expected a TypeError, got: " + e);
+}
+
+/******************************************************************************/
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
+
+print("Tests complete");