[clang] [clang] check deduction consistency when partial ordering function templates (PR #100692)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

Yep, GCC gates __cpp_template_template_args on C++17 and above.

We went with unrestricted enablement on clang, mainly because we thought we would have a full backwards compatibility solution by now.

As I said, this is fixed by https://github.com/llvm/llvm-project/pull/94981, but review is taking a while.
I tried that on your reduced example.
If you can try that patch and verify it does fix everything on SPEC 2017, I would appreciate it, as I don't have access to it's source code.

https://github.com/llvm/llvm-project/pull/100692