Regressed in <https://hg.mozilla.org/mozilla-central/rev/42056a433aee>
Bug 321831 didn't regress. How can I test this regression?
No idea, I just saw the warning in the default case being hit.
Created attachment 633492 [details] testcase document.all() throws a string "An error occurred throwing an exception" even before bug 743888.
Created attachment 633679 [details] [diff] [review] Replace nsDOMClassInfo::ThrowJSException with xpc::Throw
Created attachment 633786 [details] [diff] [review] Replace nsDOMClassInfo::ThrowJSException with xpc::Throw Removed unnecessary headers and fixed a typo.