Enable latest versions of compilers on main

[neatudarius]

Enable latest versions of compilers on main

• Enable gcc-15
• Enable gcc-14
• Enable gcc-13
• Enable gcc-12
• Enable clang-20
• Enable clang-19
• Enable clang-18
• Enable clang-17
• Enable clang-16
• TBD msvc

[ClausKlein]

NOTE: GCOV_EXECUTABLE should be set for all compilers in all toolchains!

see too https://github.com/search?q=repo%3Abeman-project%2Foptional26%20path%3A%2F%5Eetc%5C%2F%2F%20GCOV&type=code

[RaduNichita]

As per https://gcc.gnu.org/releases.html, gcc-15 has not been released yet, so it can't be added for an official ubuntu repository for now.

[RaduNichita]

clang-20 should be already enabled in both CMakePresets.json and ci.yml

[steve-downey]

Whether it's released or not, tracking the upstream to be released compiler both to check that our code does not break as well as reporting unexpected breaks is extremely useful for a component that is going to land in an unreleased library.

Clang-21 is available now from the LLVM apt repo. For GCC 15, or next in general, finding a source is the trick. Building GCC is fairly straightforward, but a bit much just to test optional.

[neatudarius]

@RaduNichita , do we have any pending tasks here?

[RaduNichita]

Sorry for the delay. For now, I think we have to wait for gcc-15. As for clang-16, I am still looking for some issue with building here - https://github.com/RaduNichita/optional/actions/runs/13906823660/job/38911750231

[neatudarius]

Sorry for the delay. For now, I think we have to wait for gcc-15. As for clang-16, I am still looking for some issue with building here - https://github.com/RaduNichita/optional/actions/runs/13906823660/job/38911750231

We already support 4 versions for clang (17-20). I think we can drop clang-16 from the list. For gcc we only support 3. @steve-downey ?

If we drop clang-16, we can also remove gcc-15 from current issue.

I would be interesting to see if this repo builds on msvc.

[steve-downey]

Mar 17, 2023 wasn't that long ago. I'd actually like to add the 21, trunk, compiler. If that breaks, it's an important canary.

We only support 3 for GCC because that's as far back as the code works, I think, unless I managed to change that accidentally.