[lima]

Any observable behavior will be depended upon. A breaking change is a breaking change no matter what.

Of course it's good that they fixed the UB.

[dralley]

It's undefined behavior. Anything can happen, by definition.

I understand what you're saying, but anyone who knowingly relies on undefined behavior deserves whatever pain they get, and anyone who didn't know they were relying on undefined behavior, needed to know about it.