diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/auto-regress/bug785576.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/auto-regress/bug785576.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,11 @@
+// Binary: cache/js-dbg-64-29ca472bf2d2-linux
+// Flags: -m -n -a
+//
+sandbox = newGlobal('')
+evalcx("x=[]", sandbox)
+evalcx("\
+  x[0] = this;\
+  Object.defineProperty(x, 0, {})\
+", sandbox)
+gc()
+evalcx("x.shift()", sandbox)