I just bumped into a javascript problem that exceeds the stupidity of previous ones:
Because promises can be retained after they settle, and handlers attached thereafter are pushed on the microtask queue, a promise rejection can't be asserted to be unhandled until the promise in question is GC'd.
Of course this is nuts so engines will conclude that a promise rejection is unhandled if there are no handlers at the moment of rejection.
I hate this language.