[llvm] [ADT] Make null PointerUnion with different active members compare equal (PR #121847)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

Hm, I'm not really convinced this change is right. If PointerUnion allows having null pointers of different types, then treating them as equal may not be correct in general.

I think the fix here should either be that assigning null pointer that is not nullptr_t to a PointerUnion is invalid, or that dyn_cast_if_present should account for the different null pointers.

https://github.com/llvm/llvm-project/pull/121847