if a scope owning a resource does not gracefully drop that resource
while handling exceptions from deeper down the call stack we should
assume the resource is invalid state and drop it. currently it *is*
true that such cases do not cause resources to be freed, but thanks
to validator misuses this has so far not caused any larger problem.
Change-Id: Ie4f91bcd60a64d05c5ff9d22cc97954816d13b97