diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug686296.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug686296.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,3 @@
+load(libdir + "asserts.js");
+var o = Object.preventExtensions(new ArrayBuffer);
+assertThrowsInstanceOf(function () { o.__proto__ = {}; }, TypeError);