[clang] [AST matchers] matchers for absl Status / StatusOr (PR #160953)

[Yitzhak Mandelbaum via cfe-commits]

ymand wrote:

> This is part of the upstreaming of abseil-unchecked-statusor-use. See https://discourse.llvm.org/t/rfc-abseil-unchecked-statusor-use-check/87998
> 
> These matchers are used in the upcoming model, but also in a downstream version which extends the model to support some internal constructs. This is why they cannot be internal to the model.

I think that, rather than referencing an existing downstream version, you might want to motivate as a generaly feature. For that, what is the downstream version using them, etc?  IIUC, they support writing extensions to the upstream model, which could equally well apply in other upstream uses.

https://github.com/llvm/llvm-project/pull/160953