I wrote Object::Deadly because I was tired of diagnostic modules forgetting to watch for overloaded objects. It'd be nice for it to use Carp::Clan but C::Clan suffers from the same bug O::Deadly is meant to help test for!
http://rt.cpan.org//Ticket/Display.html?id=21002 contains a patch to bring Carp::Clan 5.3 up to 5.4 which *is* smart about overloading. I also wrote some tests for C::Clan that use O::Deadly because that's exactly what it's there for.
I'm amused by this - just getting O::Deadly off the ground required patching some of it's infrastructure.
Oh yes, infrastructure? I have a rant coming about the evil, evil, evil UNIVERSAL::require module.