diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/testBug629974.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/testBug629974.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,7 @@
+foo = {}
+foo.y = 3;
+foo.y = function () {}
+Object.defineProperty(foo, "y", { set:function(){} })
+gc()
+delete foo.y
+gc();