[clang] [clang] Enable C++17 relaxed template template argument matching by default (PR #89807)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

> Hi, is there a way to make a compile-time check for this feature?

Yes, this is exposed by a standard feature testing macro: https://en.cppreference.com/w/cpp/feature_test#cpp_template_template_args

> 
> Looking at
> 

Thanks for reporting this. A few questions:
* Does https://github.com/llvm/llvm-project/pull/90820 help here?
* Does it reproduce with GCC, using `-std=c++17` and above?
* Are you able to reduce this test case?


https://github.com/llvm/llvm-project/pull/89807