[libc++][ranges][abi-break] Fix `movable_box` overwriting memory of data that lives in the tail padding (#71314)

fixes #70506

The detailed problem description is in #70506

The original propo

[libc++][ranges][abi-break] Fix `movable_box` overwriting memory of data that lives in the tail padding (#71314)

fixes #70506

The detailed problem description is in #70506

The original proposed fix was to remove `[[no_unique_address]]` except
when `_Tp` is empty.

Edit:
After the discussion in the comments below, the new fix here is to
remove the `[[no_unique_address]]` from `movable_box` in the cases where
we need to add our own assignment operator, which has contains the
problematic `construct_at`

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[libc++][ranges] Implement P2494R2 (Relaxing range adaptors to allow for move only types)

Implement P2494R2 `Relaxing range adaptors to allow for move only types`

https://open-std.org/jtc1/sc22/wg2

[libc++][ranges] Implement P2494R2 (Relaxing range adaptors to allow for move only types)

Implement P2494R2 `Relaxing range adaptors to allow for move only types`

https://open-std.org/jtc1/sc22/wg21/docs/papers/2022/p2494r2.html#wording-ftm

According to the words in P2494R2, I haven't add new test for `drop_while_view`, `take_while_view` and `filter_view`, because these views has the requirement that the predicate is an `indirect_unary_predicate`, which requires that the predicate is `copy_constructible`, so they still can't accept move only types as predicate.

```
[P2483R0] also suggests future work to relax the requirements on the predicate types stored by standard views. This paper does not perform this relaxation, as the copy constructibility requirement is enshrined in the indirect callable concepts ([indirectcallable.indirectinvocable]). Thus, while this paper modifies the views that currently use copyable-box for user provided predicates, it only does so to apply the rename of the exposition-only type to movable-box; it does not change any of the constraints on those views. It does, however, relax the requirements on invocables accepted by the transform family of views, because those are not constrained using the indirect callable concepts.
```

Reviewed By: #libc, var-const

Differential Revision: https://reviews.llvm.org/D151629

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[libc++] Qualifies size_t.

This has been done using the following command

find libcxx/test -type f -exec perl -pi -e 's|^([^/]+?)((?<!::)size_t)|\1std::\2|' \{} \;

And manually removed some fals

[libc++] Qualifies size_t.

This has been done using the following command

find libcxx/test -type f -exec perl -pi -e 's|^([^/]+?)((?<!::)size_t)|\1std::\2|' \{} \;

And manually removed some false positives in std/depr/depr.c.headers.

The `std` module doesn't export `::size_t`, this is a preparation for that module.

Reviewed By: ldionne, #libc, EricWF, philnik

Differential Revision: https://reviews.llvm.org/D146088

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[libc++] Make <ranges> non-experimental

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://re

[libc++] Make <ranges> non-experimental

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

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[libc++] Replace _LIBCPP_HAS_NO_CONCEPTS with _LIBCPP_STD_VER > 17. NFCI.

All supported compilers that support C++20 now support concepts. So, remove
`_LIB_LIBCPP_HAS_NO_CONCEPTS` in favor of `_LIBC

[libc++] Replace _LIBCPP_HAS_NO_CONCEPTS with _LIBCPP_STD_VER > 17. NFCI.

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

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[libc++] Work around a Clang bug in transform_view, and regression-test.

Clang trunk rejects the new test case, but this is a Clang bug
(PR47414, 47509, 50864, 44833).

```
In module 'std' imported

[libc++] Work around a Clang bug in transform_view, and regression-test.

Clang trunk rejects the new test case, but this is a Clang bug
(PR47414, 47509, 50864, 44833).

```
In module 'std' imported from /Users/aodwyer/llvm-project/libcxx/test/std/ranges/range.adaptors/range.transform/general.pass.cpp:17:
/Users/aodwyer/llvm-project/build2/include/c++/v1/__ranges/transform_view.h:85:44: error: constraints not satisfied for alias template 'range_reference_t' [with _Rp = const NonConstView]
regular_invocable<const _Fn&, range_reference_t<const _View>>
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/aodwyer/llvm-project/build2/include/c++/v1/__ranges/transform_view.h:416:25: note: in instantiation of template class 'std::ranges::transform_view<NonConstView, (lambda at /Users/aodwyer/llvm-project/libcxx/test/std/ranges/range.adaptors/range.transform/general.pass.cpp:73:71)>' requested here
-> decltype( transform_view(_VSTD::forward<_Range>(__range), _VSTD::forward<_Fn>(__f)))
^
```

We can work around this by adding a layer of indirection: put the
problematic constraint into a named concept and Clang becomes more
amenable to SFINAE'ing instead of hard-erroring.

Drive-by simplify `range.transform/general.pass.cpp` to make it clearer
what it's actually testing in this area.

Differential Revision: https://reviews.llvm.org/D115116

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[libc++] [test] s/ContiguousView/MoveOnlyView/g. NFCI.

The unique (ha!) thing about this range type is that it's move-only.
Its contiguity is unsurprising (most of our test ranges are contiguous).
D

[libc++] [test] s/ContiguousView/MoveOnlyView/g. NFCI.

The unique (ha!) thing about this range type is that it's move-only.
Its contiguity is unsurprising (most of our test ranges are contiguous).
Discussed in D111231 but committed separately for clarity.

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[libc++][NFC] Refactor tests for transform_view

Adjust the names of helper function objects to represent better what
they do, as suggested in the review of D107098.

[libc++] Remove Lit annotations for unsupported GCC versions from the test suite

Since we officially don't support several older compilers now, we can
drop a lot of the markup in the test suite. Thi

[libc++] Remove Lit annotations for unsupported GCC versions from the test suite

Since we officially don't support several older compilers now, we can
drop a lot of the markup in the test suite. This helps keep the test
suite simple and makes sure that UNSUPPORTED annotations don't rot.

This is the first patch of a series that will remove annotations for
compilers that are now unsupported.

Differential Revision: https://reviews.llvm.org/D107787

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[libc++][NFC] Fix copy-paste error in the transform_view tests

[libc++] Disable incomplete library features.

Adds a new CMake option to disable the usage of incomplete headers.
These incomplete headers are not guaranteed to be ABI stable. This
option is intende

[libc++] Disable incomplete library features.

Adds a new CMake option to disable the usage of incomplete headers.
These incomplete headers are not guaranteed to be ABI stable. This
option is intended to be used by vendors so they can avoid their users
from code that's not ready for production usage.

The option is enabled by default.

Differential Revision: https://reviews.llvm.org/D106763

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[libcxx][ranges] Add `ranges::transform_view`.

Reviewed By: cjdb, ldionne, #libc

Differential Revision: https://reviews.llvm.org/D103056