C++20 features test project

This project contains simple C++20 code samples and a bit of CMake code to test if they are supported by a given compiler.

Support of the C++20 standard

Compiler	Concept	Consteval	Update Kokkos requirements
GCC	10.1.0	10.1.0	Yes
Clang	10.0.1	9.0.1	No
AppleClang	12.0.0? (partial)	15.0.0?	Yes
IntelLLVM	<2022.1.1	<2022.1.1	Yes (for CPU)
NVCC	12.0.0	12.0.0	Yes
NVHPC	20.11	20.7?	No
ROCM	<3.7	<3.7	No
MSVC	19.30?	19.29?	Yes
ARM/Clang

Notes:

• "?" denotes the version was fetched from cppreference.com, but not tested experimentally;
• "<" denotes the version is the lowest tested, and is not guaranteed to be the version from which the feature started to be available.

Support of the C++20 standard library

Compiler	Comparison of integers	Span	Source location	Update Kokkos requirements
GCC	10.1.0	10.1.0	11.1.0	Yes
Clang	11.1.0	11.1.0	15.0.7	Yes
AppleClang	13.1.6?	10.0.0?	15.0.0?	Yes
MSVC	19.27?	19.26	19.29?	Yes
ARM/Clang

Notes:

• "?" denotes the version was fetched from cppreference.com, but not tested experimentally;
• "<" denotes the version is the lowest tested, and is not guaranteed to be the version from which the feature started to be available.