[clang] [APINotes] Diagnose invalid Where.Parameters selectors (PR #209408)

[via cfe-commits]

StoeckOverflow wrote:

Thanks for the quick feedback. Pushed an update addressing the review comments and the CI failure.

The unmatched-selector diagnostics no longer use DeclContext lookup and only inspect already-loaded declarations, avoiding the assertion failure in the ObjC forward-declaration APINotes test. I also applied the requested cleanup around collecting stored selectors from the reader and printing selector lists in diagnostics.

https://github.com/llvm/llvm-project/pull/209408