[clang] Rough first stab at addressing #85120 (PR #85147)

[Doug Wyatt via cfe-commits]

dougsonos wrote:

> @dougsonos I may have some time to look into this since there are probably (as always) some annoying edge cases—particularly w/ templates. Would you be fine with me committing to this branch or would it be easier for you if I made a separate branch for that? Either is fine by me.

It might be simplest if you make your own branch, borrowing whatever from mine helps. Thanks.

https://github.com/llvm/llvm-project/pull/85147