[clang] [clang] fix assertion substituting decltype parameters during partially ordered deduction (PR #214130)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

> Right, this is why I was so worried - it seemed far to simple a fix to have been something that would have been left as a fixme. I wonder why tests aren't failing (though I guess linux ones are so maybe some tests are inappropriately tagged as requiring a specific config).

It seems you are hitting failures on libc++ tests, and those are only tested on linux.

That's weird though, I expected there to be tests for this in the clang suite as well (except for 1) in my previous comment, because that was a new issue).

You should try extracting test cases from the libc++ failures and add them as regular clang regression tests.

https://github.com/llvm/llvm-project/pull/214130