Fix compiling with Cuda 13.1

[masterleinad]

Corresponds to kokkos/kokkos#8801.
Thanks @mhoemmen for forwarding the issue and getting the fix for the reproducer!

[mhoemmen]

Thanks for working on this! : - ) Great work with the fix!

For the future (not necessarily this PR), should we consider using MDSPAN_IMPL_TRAIT throughout instead of the ::value or _v trait variants explicitly? include/experimental/__p0009_bits/macros.hpp defines MDSPAN_IMPL_TRAIT as follows.

#if MDSPAN_IMPL_USE_VARIABLE_TEMPLATES
#  define MDSPAN_IMPL_TRAIT(TRAIT, ...) TRAIT##_v<__VA_ARGS__>
#else
#  define MDSPAN_IMPL_TRAIT(TRAIT, ...) TRAIT<__VA_ARGS__>::value
#endif

Using MDSPAN_IMPL_TRAIT thus should make back-porting to C++14 possible, while still requiring use of the _v traits in Kokkos (that requires C++17 at least).

[mhoemmen]

Thanks for the fix!

[JBludau]

Could you guys explain a bit what is the problem and how you got to the solution? In the current state I have problems following

[masterleinad]

Could you guys explain a bit what is the problem and how you got to the solution? In the current state I have problems following

We reported the issue to NVIDIA and they found that this change fixes the reproducer. It turns out that it's also enough to fix all compilation problems. Accrding to them, it's an EDG-related bug. There is no good explanation otherwise why this would make any difference.