[clang] [ASTImporter] Fix infinite recurse on return type declared inside body (#68775) (PR #89096)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

> I tested this idea, might be like this:

I meant something else. This patch makes it so the delayed function type importation happens unconditionally.
I was aware that change would cause breakages.

What I meant is that, we have a special sugar type node that marks deduction, this AutoType, and we apply it everywhere else, except this lambda case you exposed. I was going to suggest we do the same for these lambdas. That would make things more consistent.



https://github.com/llvm/llvm-project/pull/89096