[2026-03 LWG Motion 15] P3795R2 Miscellaneous Reflection Cleanup

[eisenwave]

Fixes #8849
Fixes NB US 42-078, US 85-150, US 122-184, US 128-192, US 95-202, and US 131-195 (C++26 CD).

Also fixes cplusplus/papers#2401
Also fixes https://github.com/cplusplus/nbballot/issues/654
Also fixes https://github.com/cplusplus/nbballot/issues/729
Also fixes https://github.com/cplusplus/nbballot/issues/753
Also fixes https://github.com/cplusplus/nbballot/issues/761
Also fixes https://github.com/cplusplus/nbballot/issues/771
Also fixes https://github.com/cplusplus/nbballot/issues/764
Also fixes cplusplus/nbballot#776

[eisenwave]

I'm confused by the seemingly incorrectly cited text underneath access_context::current(). The paper believes that some parts are in separate paragraphs that are actually all down in Remarks.

Maybe the paper is relative to an old draft.

UPDATE: Yeah, seems to be relative to an old draft. The PR in that area should be correct, and the difference in base draft doesn't seem to cause any problem.

[eisenwave]

Also ... I guess we're changing all this stuff and adding new functions, but we're not bumping __cpp_lib_reflection? Weird.

@brevzin would love some feedback on the issues I'm having here.

[brevzin]

Also ... I guess we're changing all this stuff and adding new functions, but we're not bumping __cpp_lib_reflection? Weird.

Yeah, let's bump both __cpp_impl_reflection (for annotations on function parameters) and __cpp_lib_reflection (for all the rest). There's another paper at this meeting that also bumps __cpp_lib_reflection, but that one just adds one function, so I think fine to assign both the same value. @jwakely, sound good?

[jensmaurer]

@eisenwave , this also fixes US 100-207. Please amend the commit description.

[eisenwave]

this also fixes US 100-207. Please amend the commit description.

Done. I've also resolved the merge conflict between

• https://wiki.isocpp.org/uploads/2026-03_Croydon-LWGStrawPollsStaging_-_P3795r2.html#pnum_88
• https://cplusplus.github.io/LWG/issue4496

[tkoeppe]

I'll start reviewing+merging this now; if you have any further change requests or comments, please just leave a comment and don't change the patch. Thanks!