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
The existing tests for transform_view::iterator weren't quite right,
and can be simplified now that we have more of C++20 available to us.
Having done that, let's use the same pattern for iota_view::iterator
as well.
Differential Revision: https://reviews.llvm.org/D110774
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
* <__algorithm/iter_swap.h>
* <__algorithm/swap_ranges.h>
* <__functional/is_transparent.h>
* <__memory/uses_allocator.h>
* <__ranges/drop_view.h>
* <__ranges/transform_view.h>
* <shared_mutex>
* <span>
Also updates header inclusions that were affected.
**NOTE:** This is a proper subset of D105932. Since the content has
already been LGTM'd, I intend to merge this patch without review,
pending green CI. I decided it would be better to move these changes
into their own commit since the former patch has undergone further
changes and will need yet another light review. In the event any of
that gets rolled back (for whatever reason), the changes in this patch
won't be affected.
Differential Revision: https://reviews.llvm.org/D106040
Arthur O'Dwyer