[clang] [Clang] Make `-Wreturn-type` default to an error. (PR #123464)

[via cfe-commits]

https://github.com/cor3ntin commented:

Thanks a lot for working on this.

It seems a bit ambitious to do this at the end of the cycle (no time to react to feedback).

However, we might want to take what is offered and minimize churn.

How about
 - in this patch you modify the tests, and the test runner (hopefully lit config can do that, I haven't checked) such that ~all tests (including new ones) use -Werror=return-type (we might want to have tests where it's just a warning to make sure this still works)

 - In a separate patch we flip the default.

it would be a lot less disruptive in case we need to revert something.

WDYT?







https://github.com/llvm/llvm-project/pull/123464