diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/testBug584650.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/testBug584650.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,9 @@
+if (typeof gczeal != "function")
+    gczeal = function() {}
+
+// don't crash
+x = (evalcx('lazy'))
+x.watch("", function () {})
+gczeal(1)
+for (w in x) {}
+