P2321R2 has been implemented in various PRs. Based on the discussion
in #105169, the last bit in iterator.concept.winc doesn't require
any changes, so we can actually mark this as done.
Fixes#105169
[P1789R3](https://isocpp.org/files/papers/P1789R3.pdf) was accepted for
C++26 through LWG motion 14 at the 2025 Kona meeting. This patch
implements it, along with tests and documentation changes.
Closes#167268
---------
Co-authored-by: Tsche <che@pydong.org>
This implements all of [P2404R3](https://wg21.link/p2404r3)'s concept
changes.
---------
Co-authored-by: A. Jiang <de34@live.cn>
Co-authored-by: Louis Dionne <ldionne.2@gmail.com>
Resolves#148131
- Unlock `std::optional<T&>` implementation
- Allow instantiations of `optional<T(&)(...)>` and `optional<T(&)[]>`
but disables `value_or()` and `optional::iterator` + all `iterator`
related functions
- Update documentation
- Update tests
<https://wg21.link/P2641R4>
Implements the C++26 function in `<type_traits>` [meta.const.eval] (and
the corresponding feature test macro `__cpp_lib_is_within_lifetime`)
```c++
template<class T>
consteval bool is_within_lifetime(const T*) noexcept;
```
This is done with the `__builtin_is_within_lifetime` builtin added to
Clang 20 by #91895 / 2a07509c8d3c8b5b2c88e4f73dde0071bf506870. This is
not (currently) available with GCC.
This implementation has provisions for LWG4138
<https://cplusplus.github.io/LWG/issue4138> where it is ill-formed to
instantiate `is_within_lifetime<T>` with a function type `T`.
Closes#105381
Co-authored-by: Mital Ashok <mital@mitalashok.co.uk>
Resolves#105430
- Implement all required pieces of P3168R2
- Leverage existing `wrap_iter` and `bounded_iter` classes to implement
the `optional` regular and hardened iterator type, respectively
- Update documentation to match
And constrain the new `operator==` since C++26.
This patch implements parts of P2165R4, P2944R3, and a possibly improved
resolution of LWG3882. Currently, libstdc++ and MSVC STL constrain the
new overloads in the same way.
Also set feature-test macro `__cpp_lib_constrained_equality` and add
related release note, as P2944R3 will completed with this patch.
Fixes#136765Fixes#136770Fixes#105424
Fixes#105260
This patch applies the change as a DR to C++20. The rationale is that
the paper is more like a bug fix. It does not introduce new features, it
simply changes an existing behaviour (as a bug fix). MSVC STL DRed this
paper to C++20 as well.
# Overview
As a disclaimer, this is my first PR to LLVM and while I've tried to
ensure I've followed the LLVM and libc++ contributing guidelines,
there's probably a good chance I missed something. If I have, just let
me know and I'll try to correct it as soon as I can.
This PR implements `std::ranges::iota` and
`std::ranges::out_value_result` outlined in
[P2440r1](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p2440r1.html).
As outlined in the paper above, I've:
- Implemented `out_value_result` and added to `<algorithm>`
- Added `out_value_result`, `iota_result`, and two overloads of `iota`
to `std::ranges` in `<numeric>`
- Updated the version macro `__cpp_lib_ranges_iota` in `<version>`
I've also added tests for `ranges::iota` and `ranges::out_value_result`.
Lastly, I added those structs to the appropriate module files.
Partially implements #105184
EDIT: Forgot to mention in the original post, thanks to @hawkinsw for
taking a look at a preliminary version of this PR!
# TODOs
- [x] Updating the range [status
doc](https://github.com/jamesETsmith/llvm-project/blob/main/libcxx/docs/Status/RangesMajorFeatures.csv)
- [x] Ensure all comments from https://reviews.llvm.org/D121436 are
addressed here
- [X] EDIT (I'll do this in a separate PR). ~~I'm open to implementing
the rest of P2440r1 (`ranges::shift_left` and `ranges::shift_right`) if
that's ok, I just wanted to get feedback on `ranges::iota` first~~
- [x] I've been having trouble building the modules locally and want to
make sure that's working properly
Closes: #134060
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
This patch implements https://wg21.link/P2747R2.
The library changes affect direct `operator new` and `operator new[]`
calls even when the core language changes are absent.
The changes are not available for MS ABI because the `operator new` and
`operator new[]` are from VCRuntime's `<vcruntime_new.h>`. A feature
request was submitted for that [1].
As a drive-by change, the patch reformatted the whole `new.pass.cpp` and
`new_array.pass.cpp` tests.
Closes#105427
[1]: https://developercommunity.visualstudio.com/t/constexpr-for-placement-operator-newope/10730304.
This patch implements https://wg21.link/p2609r3.
The test code was originally authored by JMazurkiewicz.
Notes:
- P2609R3 is not officially a Defect Report, but MSVC STL
implements it in C++20 mode.
Moreover, P2609R3 and P2997R1 touch exactly the same set of
concepts, and MSVC STL and libc++ have already treated P2997R1
as a DR.
- This patch also adjusted feature-test macros.
+ In C++20 mode, the value of __cpp_lib_ranges should be `202110L` because
- `202202L` covers `range_adaptor_closure` (P2387R3), and
- `202207L` covers move-only types in range adaptors (P2494R2).
And all of these changes are only available since C++23 mode.
+ In C++23 mode, the value should be `202406L` because
- `202211L` covers removing poison overloads (P2602R2),
- `202302L` covers relaxing projected value types (P2609R3), and
- `202406L` covers removing requirements on `iter_common_reference_t` (P2997R1).
And all of these changes are already or being implemented.
Fixes#105253.
Co-authored-by: Jakub Mazurkiewicz <mazkuba3@gmail.com>
This trait is implemented in C++26 conditionally on the compiler
supporting the __builtin_is_virtual_base_of intrinsic. I believe only
tip-of-trunk Clang currently implements that builtin.
Closes#105432
Implements [P1223R5][] completely.
Includes an implementation of `find_last`, `find_last_if`, and
`find_last_if_not`.
[P1223R5]: https://wg21.link/p1223r5
This patch implements P2389R2, which was adopted at the St. Louis meeting.
It builds upon previous enhancements from P2299R3, which introduced deduction
guides and the `dextents` alias template.
In order to define the format __cpp_lib_format to its initial value
(201907) these papers need to be completed:
- P0645R10 Text Formatting
- P1652R1 Printf corner cases in std::format
- 1361R2 Integration of chrono with text formatting The first two have
been implemented for a while the latter is almost done.
The next value (202106) requires:
- P2216R3 std::format improvements which has been implemented
The next value (202110) requires:
- P2418R2 Add support for std::generator-like types to std::format
- P2372R3 Fixing locale handling in chrono formatters The first one has
been implemented for a while the latter is almost done. The latter paper
is a DR against 1361R2 and both are implemented at the same time.
We've had user feedback that the missing of the __cpp_lib_format makes
their lives harder (https://github.com/llvm/llvm-project/issues/77773).
The missing papers 1361R2 and P2372R3 are very close to completion and
might completed before LLVM-19, but it will be a close call. This has
been discussed in the monthly libc++ meeting and we decided to set the
__cpp_lib_format so it will be set in LLVM-19.
Based on the discussion and the implementation status the
__cpp_lib_format is set to 202110.
Fixes#77773
The feature has been implemented in LLVM 18 as an experimental feature.
This marks the paper as complete and sets the feature-test macro.
Implements
- P2465R3 Standard Library Modules std and std.compat
Fixes: https://github.com/llvm/llvm-project/issues/89579
The paper
P0768R1 Library Support for the Spaceship (Comparison) Operator
did not add a feature-test macro. This omission has been corrected in
P1353R0 Missing Feature Test Macros
This enables the FTM for P0768R1
Fixes: https://github.com/llvm/llvm-project/issues/73953
---------
Co-authored-by: S. B. Tam <cpplearner@outlook.com>
[P2845R8](https://wg21.link/P2845R8) "Formatting of
`std::filesystem::path`" and [P2587R3](https://wg21.link/P2587R3)
"`to_string` or not `to_string`" are C++26 features, so they should be
marked accordingly in `generate_feature_test_macro_components.py`.
I verified that without my changes, running the script produced no
edits. Then with my changes, I ran the script to regenerate all files,
with no other manual edits.
Found while running libc++'s tests with MSVC's STL, which noticed this
because it's currently a C++23-only implementation.
Note that @H-G-Hristov has a draft implementation of P2587R3: #78100
