When we ship LLVM 16, <ranges> won't be considered experimental anymore.
We might as well do this sooner rather than later.
Differential Revision: https://reviews.llvm.org/D132151
For an lvalue reference to a move only view x, views::all(x) gives hard error because the expression inside noexcept is not well formed and it is not SFINAE friendly.
Given a move only view type `V`, and a concept
```
template <class R>
concept can_all = requires {
std::views::all(std::declval<R>());
};
```
The expression `can_all<V&>` returns
libstdc++: false
msvc stl : false
libc++ : error: static_cast from 'V' to 'typename decay<decltype((std::forward<V &>(__t)))>::type' (aka 'V') uses deleted function
noexcept(noexcept(_LIBCPP_AUTO_CAST(std::forward<_Tp>(__t))))
The standard spec has its own problem, the spec says it is expression equivalent to `decay-copy(E)` but the spec of `decay-copy` does not have any constraint, which means the expression `decay-copy(declval<V&>())` is well-formed and the concept `can_all<V&>` should return true and should error when instantiating the function body of decay-copy. This is clearly wrong behaviour in the spec and we will probably create an LWG issue. But the libc++'s behaviour is clearly not correct. The `noexcept` is an "extension" in libc++ which is not in the spec, but the expression inside `noexpect` triggers hard error, which is not right.
Reviewed By: #libc, ldionne, var-const
Differential Revision: https://reviews.llvm.org/D128281
All supported compilers that support C++20 now support concepts. So, remove
`_LIB_LIBCPP_HAS_NO_CONCEPTS` in favor of `_LIBCPP_STD_VER > 17`. Similarly in
the tests, remove `// UNSUPPORTED: libcpp-no-concepts`.
Differential Revision: https://reviews.llvm.org/D121528
This commit reverts 5aaefa51 (and also partly 7f285f48e7 and b6d75682f9,
which were related to the original commit). As landed, 5aaefa51 had
unintended consequences on some downstream bots and didn't have proper
coverage upstream due to a few subtle things. Implementing this is
something we should do in libc++, however we'll first need to address
a few issues listed in https://reviews.llvm.org/D106124#3349710.
Differential Revision: https://reviews.llvm.org/D120683
libc++ has started splicing standard library headers into much more
fine-grained content for maintainability. It's very likely that outdated
and naive tooling (some of which is outside of LLVM's scope) will
suggest users include things such as <__ranges/access.h> instead of
<ranges>, and Hyrum's law suggests that users will eventually begin to
rely on this without the help of tooling. As such, this commit
intends to protect users from themselves, by making it a hard error for
anyone outside of the standard library to include libc++ detail headers.
Differential Revision: https://reviews.llvm.org/D106124
The logic here is that we are disabling *only* things in `std::ranges::`.
Everything in `std::` is permitted, including `default_sentinel`, `contiguous_iterator`,
`common_iterator`, `projected`, `swappable`, and so on. Then, we include
anything from `std::ranges::` that is required in order to make those things
work: `ranges::swap`, `ranges::swap_ranges`, `input_range`, `ranges::begin`,
`ranges::iter_move`, and so on. But then that's all. Everything else (including
notably all of the "views" and the `std::views` namespace itself) is still
locked up behind `_LIBCPP_HAS_NO_INCOMPLETE_RANGES`.
Differential Revision: https://reviews.llvm.org/D118736
With this patch there should be no more namespaces without closing comment
Reviewed By: ldionne, Quuxplusone, #libc
Spies: libcxx-commits
Differential Revision: https://reviews.llvm.org/D118668
The macro that opts out of `std::ranges::` functionality is called
`_LIBCPP_HAS_NO_INCOMPLETE_RANGES`, and is unrelated to this macro
which is specifically about _compiler_ support for the _syntax_.
The only non-mechanical diff here is in `<__config>`.
Differential Revision: https://reviews.llvm.org/D118507
Clang is gaining `auto(x)` support in D113393; sadly there
seems to be no feature-test macro for it. Zhihao is opening
a core issue for that macro.
Use `_LIBCPP_AUTO_CAST` where C++20 specifies we should use `auto(x)`;
stop using `__decay_copy(x)` in those places.
In fact, remove `__decay_copy` entirely. As of C++20, it's purely
a paper specification tool signifying "Return just `x`, but it was
perfect-forwarded, so we understand you're going to have to call
its move-constructor sometimes." I believe there's no reason we'd
ever need to do its operation explicitly in code.
This heisenbugs away a test failure on MinGW; see D112214.
Differential Revision: https://reviews.llvm.org/D115686
We don't use double underscores for private header names when they are
in a subdirectory with double underscores already.
Differential Revision: https://reviews.llvm.org/D108820
This patch implements the underlying mechanism for range adaptors. It
does so based on http://wg21.link/p2387, even though that paper hasn't
been adopted yet. In the future, if p2387 is adopted, it would suffice
to rename `__bind_back` to `std::bind_back` and `__range_adaptor_closure`
to `std::range_adaptor_closure` to implement that paper by the spec.
Differential Revision: https://reviews.llvm.org/D107098
We've been forgetting to add those to most of the <ranges> review.
To avoid forgetting in the future, I added an item in the pre-commit
checklist.
Differential Revision: https://reviews.llvm.org/D106287
Moves:
* `std::move`, `std::forward`, `std::declval`, and `std::swap` into
`__utility/${FUNCTION_NAME}`.
* `std::swap_ranges` and `std::iter_swap` into
`__algorithm/${FUNCTION_NAME}`
Differential Revision: https://reviews.llvm.org/D103734
Louis Dionne