On: Reducing undefined behavior in the C language

[afdbcreid]

Because it invokes UB.

[kstrauser → afdbcreid]

Well, yes, but as a C decidedly-not-an-expert, I didn't understand what kind of UB it was invoking that could make all three of those expressions simultaneously false.

[afdbcreid → kstrauser]

That is your mistake, right here. UB can cause everything, there does not need to be a "reason" or "kind of UB".

(If you are looking for an explanation how it happens in practice, see the other comment).