[libc++] Bump `__cpp_lib_optional` and `__cpp_lib_variant` (#113650)

In C++20 mode, `__cpp_lib_optional` and `__cpp_lib_variant` should be
`202106L` due to DR P2231R1.

In C++26 mode, `__cpp_lib_

[libc++] Bump `__cpp_lib_optional` and `__cpp_lib_variant` (#113650)

In C++20 mode, `__cpp_lib_optional` and `__cpp_lib_variant` should be
`202106L` due to DR P2231R1.

In C++26 mode, `__cpp_lib_variant` should be bumped to `202306L` due to
P2637R3.
- Clang 16/17 shouldn't get this bumping (as member `visit` requires
explicit object parameters), but it's very tricky to make the bumping
conditionally enabled. I _hope_ unconditionally bumping in C++26 will be
OK for LLVM 20 when the support for Clang 17 is dropped.

Related PRs:
- https://reviews.llvm.org/D102119
- #83335
- #76447

show more ...

[libc++] Update status after the St. Louis meeting. (#97951)

This updates:
- The status tables
- Feature test macros
- New headers for modules

[libc++] Update status page after the Tokyo meeting (#87395)

[libc++] Update status after the Kona meeting. (#72421)

This updates:
- The status tables
- Feature test macros (including previously missing ones)
- New headers for modules

[libc++] Adds C++26 support.

Clang has been updated to support C++26, this adds the same support for
libc++. At the moment C++23 and C++26 are identical. During the next
plenary in June the first C+

[libc++] Adds C++26 support.

Clang has been updated to support C++26, this adds the same support for
libc++. At the moment C++23 and C++26 are identical. During the next
plenary in June the first C++26 papers will be voted on.

Note like Clang this patch uses C++26 is the internal part and C++2c in
the user visible part.

Depends on D150795

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D151026

show more ...

[libc++] Updates C++2b to C++23.

During the ISO C++ Committee meeting plenary session the C++23 Standard
has been voted as technical complete.

This updates the reference to c++2b to c++23 and updat

[libc++] Updates C++2b to C++23.

During the ISO C++ Committee meeting plenary session the C++23 Standard
has been voted as technical complete.

This updates the reference to c++2b to c++23 and updates the __cplusplus
macro.

Note since we use clang-tidy 16 a small work-around is needed. Clang
knows -std=c++23 but clang-tidy not so for now force the lit compiler
flag to use -std=c++2b instead of -std=c++23.

Reviewed By: #libc, philnik, jloser, ldionne

Differential Revision: https://reviews.llvm.org/D150795

show more ...

[libc++] Removes __cpp_lib_monadic_optional.

P0798R8 "Monadic operations for std::optional" has been implemented, so
this LWG issue can be adopted.

During review it was discovered another paper bum

[libc++] Removes __cpp_lib_monadic_optional.

P0798R8 "Monadic operations for std::optional" has been implemented, so
this LWG issue can be adopted.

During review it was discovered another paper bumped the macro. The
part affecting optional of this paper is done, the variant isn't. The
status page is updated to reflect the current state.

Implements
- LWG 3621 Remove feature-test macro __cpp_lib_monadic_optional

Updates status of
- P2231R1 Missing constexpr in std::optional and std::variant

Reviewed By: #libc, philnik, ldionne

Differential Revision: https://reviews.llvm.org/D125813

show more ...

[libc++] Make .version.pass.cpp tests be compile-only tests

We don't really need to run them.