Clang/GCC: Issue with operator co_await and `winrt::impl::awaiter_finder`

[alvinhochun]

The promises winrt::fire_and_forget and winrt::impl::promise_base have the member function await_transform which uses winrt::impl::notify_awaiter, which uses winrt::impl::get_awaiter, which in turn uses winrt::impl::awaiter_finder.

When you do things like co_await 10ms in a coroutine with one of these promise types, the await_transform member function is called, and the operator co_await for std::chrono::duration is resolved by winrt::impl::get_awaiter using winrt::impl::awaiter_finder.

This works in MSVC, however Clang and GCC don't like it when the operator co_await is not declared before the definition of the awaiter_finder template class: https://godbolt.org/z/hbhhMdj3d

I believe this is the reason why some of the tests using co_await does not work on Clang without these workarounds in #1203.

Any ideas? I cannot tell which compilers are doing it wrong.

[sylveon]

Maybe it's finally time to nuke get_awaiter? #996 (comment) @kennykerr

[kennykerr]

Yep, feel free to rip it out - I confirmed that it was never adopted.

[sylveon]

Nice! Should probably remove the workarounds from the unit tests as well to make sure that functionality is covered in testing.

[kennykerr]

Here's where this was originally added. #372

[github-actions]

This issue is stale because it has been open 10 days with no activity. Remove stale label or comment or this will be closed in 5 days.

[sylveon]

@alvinhochun interested in doing this, or am I good to work on it?

[alvinhochun]

@alvinhochun interested in doing this, or am I good to work on it?

I was under the impression that you planned to work on this. Please do go ahead if you don't mind.