tree ec1256ec98eff90d643a75dec2b13f634b906006
parent a3ebb3acc9b3afe9ddfe4582932646b72c90b31c
author Marek Kurdej <marek.kurdej+llvm.org@gmail.com> 1616692151 +0100
committer Copybara-Service <copybara-worker@google.com> 1616704282 -0700

[libc++] [C++2b] [P2162] Allow inheritance from std::variant.

This patch changes the variant even in pre-C++2b.
It should not break anything, only allow use cases that didn't work previously.

Notes:
 `__as_variant` is used in `__visitation::__variant::__visit_alt`, but I haven't used it in `__visitation::__variant::__visit_alt_at`.
That's because it is used only in `__visit_value_at`, which in turn is always used on variant specializations (that's in comparison operators).

* https://wg21.link/P2162

Reviewed By: ldionne, #libc, Quuxplusone

Differential Revision: https://reviews.llvm.org/D97394

GitOrigin-RevId: 0324b46cd873abc4fabe19f4bd468d10398ffd0d