[clang] [C++26] [Contracts] Support Parser, AST and AST Serialization (1/n) (PR #205739)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

> Are you aware of https://github.com/efcs/llvm-project/tree/contracts-nightly ?
> 
> I'd rather we work on upstreaming that - which has been already reviewed by a couple of people and extensively tested than starting from scratch.
> 
> (Eric is no longer working on contracts)

Oh no. I tried to search but I didn't find that : ( . I don't have opinions to use that if that is already reviewed. But it looks like that PR wasn't sent?

https://github.com/llvm/llvm-project/pull/205739