diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/arguments/genexpr-3.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/arguments/genexpr-3.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,6 @@
+// 'arguments' is lexically scoped in genexpr in toplevel let-block.
+
+{
+    let arguments = [];
+    assertEq((arguments for (p in {a: 1})).next(), arguments);
+}