diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/for-of/semantics-06.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/for-of/semantics-06.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,8 @@
+// Deleting the .next method makes for-of stop working on arrays.
+
+load(libdir + "asserts.js");
+load(libdir + "iteration.js");
+
+var iterProto = Object.getPrototypeOf([][std_iterator]());
+delete iterProto.next;
+assertThrowsInstanceOf(function () { for (var v of []) ; }, TypeError);