diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/for-of/array-iterator-empty.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/for-of/array-iterator-empty.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,11 @@
+// Array.keys() and .entries() on an empty array produce empty iterators
+
+var arr = [];
+var ki = arr.keys(), ei = arr.entries();
+var p = Object.getPrototypeOf(ki);
+assertEq(Object.getPrototypeOf(ei), p);
+
+for (let k of ki)
+  throw "FAIL";
+for (let [k, v] of ei)
+  throw "FAIL";