[clang] [RFC] Initial implementation of P2719 (PR #113510)

[Oliver Hunt via cfe-commits]

ojhunt wrote:

I'm planning on removing the docs, but I've left them in for now just so that reviewers can read them if they want context to understand the PR.

@cor3ntin @AaronBallman @erichkeane I'm ok removing the flag, I'll look into how to diagnose the "you're using an extension/future language feature". I'm going to completely remove the optional destroying delete path, I think it's very clear now that it's a bad idea so there's no reason to keep it around.

In the meantime, I've discovered why I missed some of @cor3ntin's feedback (despite only using the annoying merge commits/push changes approach GH still drops comments from the diff if it thinks they're "outdated") so I'm going to have to spend a bunch of time trying to work out which comments are still relevant - Corentin pinged on a few but I suspect those aren't the only cases.

https://github.com/llvm/llvm-project/pull/113510