diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug646968-8.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug646968-8.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,7 @@
+// |jit-test| debug
+
+var x = 5;
+let (x = eval("x++")) {
+    assertEq(evalInFrame(0, "x"), 5);
+}
+assertEq(x, 6);