[clang] Revert "[DebugInfo] Ignore undefined constexpr constructors in constructor homing." (PR #221566)

[Clayton Knittel via cfe-commits]

ClaytonKnittel wrote:

Ah wow okay, maybe the fix could be to proactively emit full debug info for types that appear as a union member. I'm happy to accept the revert for now, and I can send out another PR later.

https://github.com/llvm/llvm-project/pull/221566