STR: * Open attached testcase * Open web console * Click the button * Notice that you get "NS_ERROR_XPC_BAD_OP_ON_WN_PROTO: Illegal operation on WrappedNative prototype object" * Keep clicking for a few seconds. * Eventually, you'll stop getting the error and the pushState will work! Surely we should either always throw or always work. It seems to be timing dependent more than number-of-clicks dependent. So maybe the error happens for the first N seconds after you open the page or something.

> * Eventually, you'll stop getting the error and the pushState will work! You'll notice because the URL of the page will change.

Might this be another variant of 593910?

I'm always getting > TypeError: 'pushState' called on an object that does not implement interface History. .. with this testcase on a nightly. Can you still reproduce? (In reply to dirk bergstrom from comment #2) > Might this be another variant of 593910? Making the bug link clickable: bug 593910.

In the testcase oldPushState is called with undefined this, which means it should throw every time with Web IDL bindings: the this object is not a History. Bound functions for the win....