diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/arrow-functions/const-1.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/arrow-functions/const-1.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,11 @@
+// Arguments with default parameters can shadow const locals.
+
+"use strict";
+
+function f() {
+    const x = 1;
+    return (x = 0) => x;
+}
+
+var g = f();
+assertEq(g(), 0);