diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug792220.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug792220.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,12 @@
+var p = Proxy.create({
+  has : function(id) {}
+});
+Object.prototype.__proto__ = p;
+function f() {
+  if (/a/.exec("a"))
+    return 1;
+  return 0;
+}
+delete RegExp.prototype.test;
+f();
+