See http://jsbin.com/pelokucuwe/1/edit?js,console Console shows that iterating over an object with a Symbol key breaks over time (theory is due to JITing). Observed: ["bar", function bar() {}] ["bar", 1] Expected: ["bar", function bar() {}] ["bar", function bar() {}] From https://github.com/emberjs/ember.js/issues/13796
(In reply to Chris J. Shull from comment #0) > See http://jsbin.com/pelokucuwe/1/edit?js,console Thank you for extracting the test case, Chris! JIT crash was fixed in r203793. *** This bug has been marked as a duplicate of bug 160211 ***