diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug510642.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug510642.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,14 @@
+// Don't crash or assert.
+
+(function () {
+    var x;
+    (eval("\
+    (function () {\
+        for (y in [0, 0]) let(a)((function () {\
+            for (w in [0, 0])\
+                x = 0\
+        })());\
+        with({}) {}\
+    })\
+    "))()
+})()