Clang C++20 Feature: P0315R4 - Lambdas in unevaluated contexts

[JVApen]

id: P0315R4
paper: https://wg21.link/p0315r4
partially implemented: status unknown

[llvmbot]

@llvm/issue-subscribers-c-20

[ecnelises]

Can we rename issue-subscribers-c-20 to issue-subscribers-cpp-20 (or something like that) to avoid confusion?

[EugeneZelenko]

@ecnelises: Please file new issue for that.

[cor3ntin]

This is marked partial because [temp.deduct] p/9 is not implemented
https://eel.is/c++draft/temp.deduct#general-9

https://godbolt.org/z/jPKr6zv7P

[llvmbot]

@llvm/issue-subscribers-clang-frontend