diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug657227.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug657227.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,39 @@
+var obj;
+var counter = 0;
+var p = Proxy.create({
+    has : function(id) {
+	if (id == 'xyz') {
+	    ++counter;
+	    if (counter == 7) {
+		obj.__proto__ = null;
+	    }
+	    return true;
+	}
+	return false;
+    },
+    get : function(id) {
+	if (id == 'xyz')
+	    return 10;
+    }
+});
+
+function test()
+{
+    Object.prototype.__proto__ = null;
+    obj = { xyz: 1};
+    var n = 0;
+    for (var i = 0; i != 100; ++i) {
+	var s = obj.xyz;
+	if (s)
+	    ++n;
+	if (i == 10) {
+	    delete obj.xyz;
+	    Object.prototype.__proto__ = p;
+	}
+
+    }
+}
+
+try {
+    test();
+} catch (e) {}