diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug601046.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug601046.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,8 @@
+// don't assert
+var f = function(){};
+for (var p in f);
+Object.defineProperty(f, "j", ({configurable: true, value: "a"}));
+Object.defineProperty(f, "k", ({configurable: true, value: "b"}));
+Object.defineProperty(f, "j", ({configurable: true, get: function() {}}));
+delete f.k;
+Object.defineProperty(f, "j", ({configurable: false}));