diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug728188.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug728188.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,9 @@
+// |jit-test| error:TypeError
+
+delete String.prototype.indexOf;
+
+function enterFunc (funcName) {
+    funcName.indexOf();
+}
+enterFunc(new Array("foo"));
+enterFunc(new String("Foo"));