By changing __cust_access::__decay_copy from a function template to a
function object we avoid ADL. That means it's fine to call it
unqualified (the compiler won't waste time doing ADL in associated
namespaces, and won't try to complete associated types).
This also makes some other minor simplications to other concepts for the
[range.access] CPOs.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/iterator_concepts.h (__cust_access::__decay_copy):
Replace with function object.
(__cust_access::__member_begin, ___cust_access::_adl_begin): Use
__decay_copy unqualified.
* include/bits/ranges_base.h (__member_end, __adl_end):
Likewise. Use __range_iter_t for type of ranges::begin.
(__member_rend): Use correct value category for rbegin argument.
(__member_data): Use __decay_copy unqualified.
(__begin_data): Use __range_iter_t for type of ranges::begin.
(cherry picked from commit cb326a6442)
I already changed the constraints for ranges::ssize to use ranges::size,
this implements the rest of LWG 3403, so that the returned type is the
signed type corresponding to the result of ranges::size.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/ranges_base.h (_SSize): Return the result of
ranges::size converted to the wider of make-signed-like-t<S> and
ptrdiff_t, rather than the ranges different type.
* testsuite/std/ranges/access/ssize.cc: Adjust expected result
for an iota_view that uses an integer class type for its
difference_type.
(cherry picked from commit 621ea10ca0)
We need to decay the result of t.data() before checking if it's a
pointer.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
PR libstdc++/100824
* include/bits/ranges_base.h (__member_data): Use __decay_copy.
* testsuite/std/ranges/access/data.cc: Add testcase from PR.
(cherry picked from commit 3e5f2425f8)
The implementation of P2091R0 was incomplete, so that some range access
CPOs used perfect forwarding where they should not. This fixes it by
consistently operating on lvalues.
Some additional changes that are not necessary to fix the bug:
Modify the __as_const helper to simplify its usage. Instead of deducing
the value category from its argument, and requiring callers to forward
the argument as the correct category, add a non-deduced template
parameter which is used for the value category and accept the argument
as an lvalue. This means callers say __as_const<T>(t) instead of
__as_const(std::forward<T>(t)).
Always use an lvalue reference type as the template argument for the
_S_noexcept helpers, so that we only instantiate one specialization for
lvalues and rvalues of the same type.
Move some helper concepts and functions from namespace std::__detail
to ranges::__cust_access, to be consistent with the ranges::begin CPO.
This ensures that the __adl_begin concept and the _Begin::operator()
function are in the same namespace, so unqualified lookup is consistent
and the poison pills for begin are visible to both.
Simplified static assertions for arrays, because the expression a+0 is
already ill-formed for an array of incomplete type.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
PR libstdc++/100824
* include/bits/iterator_concepts.h (__detail::__decay_copy)
(__detail::__member_begin, __detail::__adl_begin): Move to
namespace ranges::__cust_access.
(__detail::__ranges_begin): Likewise, and rename to __begin.
Remove redundant static assertion.
* include/bits/ranges_base.h (_Begin, _End, _RBegin, _REnd):
Use lvalue in noexcept specifier.
(__as_const): Add non-deduced parameter for value category.
(_CBegin, _CEnd, _CRBegin, _CREnd, _CData): Adjust uses of
__as_const.
(__member_size, __adl_size, __member_empty, __size0_empty):
(__eq_iter_empty, __adl_data): Use lvalue objects in
requirements.
(__sentinel_size): Likewise. Add check for conversion to
unsigned-like.
(__member_data): Allow non-lvalue types to satisfy the concept,
but use lvalue object in requirements.
(_Size, _SSize): Remove forwarding to always use an lvalue.
(_Data): Likewise. Add static assertion for arrays.
* testsuite/std/ranges/access/cdata.cc: Adjust expected
behaviour for rvalues. Add negative tests for ill-formed
expressions.
* testsuite/std/ranges/access/data.cc: Likewise.
* testsuite/std/ranges/access/empty.cc: Adjust expected
behaviour for rvalues.
* testsuite/std/ranges/access/size.cc: Likewise.
(cherry picked from commit ee9548b36a)
The three-argument form of ranges::advance is supposed to return the
difference between the second argument and the distance the iterator was
advanced. When a non-random-access iterator is not advanced (because it
already equals the sentinel) we were returning 0 rather than n - 0.
libstdc++-v3/ChangeLog:
PR libstdc++/100833
* include/bits/ranges_base.h (ranges::advance(iter, n, sentinel)):
Fix return value for no-op case.
* testsuite/24_iterators/range_operations/advance.cc: Test
return values of three-argument overload.
(cherry picked from commit d832629169)
The standard specifies std::ranges::distance etc as function templates,
but it also requires them to not be found by ADL, and to suppress ADL
when normal unqualified lookup does find them. That means they need to
be function objects.
libstdc++-v3/ChangeLog:
PR libstdc++/100768
* include/bits/ranges_base.h (advance, distance, next, prev):
Replace function templates with function objects.
* testsuite/24_iterators/headers/iterator/synopsis_c++20.cc:
Adjust for changes to function objects.
* testsuite/std/ranges/adaptors/elements.cc: Add using
declarations for names from namespace ranges.
* testsuite/std/ranges/adaptors/transform.cc: Likewise.
* testsuite/24_iterators/range_operations/100768.cc: New test.
(cherry picked from commit a49a045b92)
This introduces two new headers:
<bits/ranges_base.h> defines the minimal components needed
for using C++20 ranges (customization point objects such as
std::ranges::begin, concepts such as std::ranges::range, etc.)
<bits/ranges_util.h> includes <bits/ranges_base.h> and additionally
defines subrange, which is needed by <bits/ranges_algo.h>.
Most of the content of <bits/ranges_base.h> was previously defined in
<bits/range_access.h>, but a few pieces were only defined in <ranges>.
This meant the entire <ranges> header was needed in <algorithm> and
<memory>, even though they don't use all the range adaptors.
By moving the ranges components out of <bits/range_access.h> that file
is left defining just the contents of [iterator.range] i.e. std::begin,
std::end, std::size etc. and not C++20 ranges components.
For consistency with other C++20 ranges headers, <bits/range_cmp.h> is
renamed to <bits/ranges_cmp.h>.
libstdc++-v3/ChangeLog:
* include/Makefile.am: Add new headers and adjust for renamed
header.
* include/Makefile.in: Regenerate.
* include/bits/iterator_concepts.h: Adjust for renamed header.
* include/bits/range_access.h (ranges::*): Move to new
<bits/ranges_base.h> header.
* include/bits/ranges_algobase.h: Include new <bits/ranges_base.h>
header instead of <ranges>.
* include/bits/ranges_algo.h: Include new <bits/ranges_util.h>
header.
* include/bits/range_cmp.h: Moved to...
* include/bits/ranges_cmp.h: ...here.
* include/bits/ranges_base.h: New header.
* include/bits/ranges_util.h: New header.
* include/experimental/string_view: Include new
<bits/ranges_base.h> header.
* include/std/functional: Adjust for renamed header.
* include/std/ranges (ranges::view_base, ranges::enable_view)
(ranges::dangling, ranges::borrowed_iterator_t): Move to new
<bits/ranges_base.h> header.
(ranges::view_interface, ranges::subrange)
(ranges::borrowed_subrange_t): Move to new <bits/ranges_util.h>
header.
* include/std/span: Include new <bits/ranges_base.h> header.
* include/std/string_view: Likewise.
* testsuite/24_iterators/back_insert_iterator/pr93884.cc: Add
missing <ranges> header.
* testsuite/24_iterators/front_insert_iterator/pr93884.cc:
Likewise.
