[clang] [LifetimeSafety] Warn when lifetimebound attribute is present on the definition but not on declaration (PR #197753)

[Utkarsh Saxena via cfe-commits]

https://github.com/usx95 commented:

We have cross-tu and intra-tu suggestions to rank the usefulness of these warnings. I think we should have a similar distinction here as well. This is along the lines of @Xazax-hun suggestion to prioritise suggestions in headers (e.g. specially when the def is in a .cc file)

https://github.com/llvm/llvm-project/pull/197753