Deprecated warning in C++23 due to use of std::aligned_storage

[WopsS]

Describe the bug When a project utilizes this library and is compiled with C++23, a deprecation warning is issued by the compiler. This warning is associated with the use of std::aligned_storage<Len, Align>, which is deprecated in C++23. The deprecation warning message is as follows:

warning C4996: 'std::aligned_storage<8,8>': warning STL4034: std::aligned_storage and std::aligned_storage_t are deprecated in C++23. Prefer alignas(T) std::byte t_buff[sizeof(T)]. You can define _SILENCE_CXX23_ALIGNED_STORAGE_DEPRECATION_WARNING or _SILENCE_ALL_CXX23_DEPRECATION_WARNINGS to suppress this warning.

The warning is triggered by the following line of code: https://github.com/gracicot/kangaru/blob/36f70dba250f070c7abf844af1c0aefb55640907/include/kangaru/detail/traits.hpp#L58

To Reproduce

1. Compile a project that uses this library with C++23.

Expected behavior

The expected behavior is for the project to compile without any deprecation warnings, without the need to suppress them.

Desktop (please complete the following information):

• OS: Windows
• Compiler MSVC
• Version 19.35

Additional context

A potential solution could be to create a struct using alignas. However, if a project enables the /W4 flag, it will yield Compiler Warning (level 4) C4324. An alternative workaround may involve using #pragma warning(suppress : 4324), but this seems like a less-than-ideal, somewhat hacky solution.

Is alignment necessary for this library? If not, the code could be refactored to eliminate the need for alignment.

[gracicot]

Thank you for the report! I'll patch it as soon as I find some time

[gracicot]

Fixed in 686d36af8a614db5e74fc88bcc21e3f72e80e862 on master, thank you!

[WopsS]

Thanks! The issue is that right now it doesn't compile :(

Maybe just char[size] would be enough here (https://github.com/gracicot/kangaru/commit/686d36af8a614db5e74fc88bcc21e3f72e80e862). If alignas is really necessary than something like should work:

template<std::size_t size, std::size_t align>
struct aligned_storage_t
{
    alignas(align) char data[size];
};

[gracicot]

Yeah I saw the pipeline failing on non gcc compiler, seems like I used an extension without knowing. I'll probably just put alignas(align) unsigned char data[size]; at the places I used aligned_storage_t in the past and removing that alias.

(alignment is actually important or there will be undefined behaviour, x86 just enable broken code to work in some common case)

[gracicot]

It should be okay now, I can see the master branch passing on all runners

[WopsS]

Thank you for the fix! :D