[tab:cpp.cond.ha] Add attribute 'indeterminate' CWG3020

[jensmaurer]

P2795R5, approved in March, 2024, added the [[indeterminate]] attribute, but neglected to amend the table of attributes supported by __has_cpp_attribute.

[tkoeppe]

Huh, what an oversight! This should have spent a lot more time in CWG...

[timsong-cpp]

Heh, the last time something like this came up (for [[assume]]), it was reported here first and made into a core issue. So this time I tried to report a core issue directly and it's being handled editorially...

No objections to this course of action though.

[jensmaurer]

Heh, the last time something like this came up (for [[assume]]), it was reported #5740 and made into a core issue.

We're consistently inconsistent.

But maybe someone (@hubert-reinterpretcast?) prefers this as a core issue for visibility.

[hubert-reinterpretcast]

But maybe someone (@hubert-reinterpretcast?) prefers this as a core issue for visibility.

This isn't really editorial. Also, implementers might be working from the adopted paper and having the core issue will put the __has_cpp_attribute update on the radar.

[jensmaurer]

CWG3020