[clang-tools-extra] [clang-tidy] performance-unnecessary-copy-init: Add a hook... (PR #73921)

[Clement Courbet via cfe-commits]

legrosbuffle wrote:

> First what's a purpose of this change. Is there any other check that will need it or not ?

We have a downstream check that wants to do additional processing after this one. We can't submit that check because it depends on a large piece of downstream infrastructure.

> With current implementation I don't see any "custom behaviour" that could be implemented, as this act more like observer.

Indeed, the downstream check does not change the behaviour, it does extra stuff in addition what the check already does. I've rephrased the commit message to make that clearer.

https://github.com/llvm/llvm-project/pull/73921