diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/for-of/proxy-1.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/for-of/proxy-1.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,28 @@
+// Basic for-of test with Proxy.
+
+function iterableProxy(arr) {
+    return Proxy.create({
+        getPropertyDescriptor: function (name) {
+            for (var obj = arr; obj; obj = Object.getPrototypeOf(obj)) {
+                var desc = Object.getOwnPropertyDescriptor(obj, name);
+                if (desc)
+                    return desc;
+            }
+            return undefined;
+        }
+    });
+}
+
+var s = '';
+var arr = ['a', 'b', 'c', 'd'];
+var p = iterableProxy(arr);
+
+// Test the same proxy twice. Each time through the loop, the proxy handler's
+// getPropertyDescriptor method will be called 10 times (once for 'iterator',
+// five times for 'length', and once for each of the four elements).
+for (var i = 0; i < 2; i++) {
+    var j = 0;
+    for (var x of p)
+        assertEq(x, arr[j++]);
+    assertEq(j, arr.length);
+}