[Bug c++/101214] New: ranges::split_view​::​sentinel lacks default constructor

[Bug c++/101214] New: ranges::split_view​::​sentinel lacks default constructor

[hewillk at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101214

            Bug ID: 101214
           Summary: ranges::split_view​::​sentinel lacks default
                    constructor
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hewillk at gmail dot com
  Target Milestone: ---

#include <ranges>

int main() {
  auto r = std::views::iota(0) | std::views::take(5);
  decltype(std::views::split(r, 0).end()) e{};
}

https://godbolt.org/z/oK9zbE5WG

[Bug libstdc++/101214] ranges::split_view​::​sentinel lacks default constructor

[hewillk at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101214

--- Comment #1 from 康桓瑋 <hewillk at gmail dot com> ---
(In reply to 康桓瑋 from comment #0)
> #include <ranges>
> 
> int main() {
>   auto r = std::views::iota(0) | std::views::take(5);
>   decltype(std::views::split(r, 0).end()) e{};
> }
> 

Another tiny issue is that in ranges#L3309:

  constexpr
  split_view(_Range&& __r, range_value_t<_Range> __e)
    : _M_pattern(views::single(__e)),
      _M_base(views::all(std::forward<_Range>(__r)))
  { }

it should be _M_pattern(views::single(std::move(__e))) just like
lazy_split_view.

[Bug libstdc++/101214] ranges::split_view​::​sentinel lacks default constructor

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101214

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |ppalka at gcc dot gnu.org
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-06-25
                 CC|                            |ppalka at gcc dot gnu.org

[Bug libstdc++/101214] ranges::split_view​::​sentinel lacks default constructor

[hewillk at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101214

--- Comment #2 from 康桓瑋 <hewillk at gmail dot com> ---
In ranges#L3367:

   _Iterator() requires default_initializable<iterator_t<_Vp>> = default;

This constraint seems to be redundant because forward_iterator always satisfies
default_initializable.

[Bug libstdc++/101214] ranges::split_view​::​sentinel lacks default constructor

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101214

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:73464a472aa4e86359f1a5dc529394fe5152fec0

commit r12-2356-g73464a472aa4e86359f1a5dc529394fe5152fec0
Author: Patrick Palka <ppalka@redhat.com>
Date:   Fri Jul 16 09:44:32 2021 -0400

    libstdc++: Give split_view::_Sentinel a default ctor [PR101214]

    This gives the new split_view's sentinel type a defaulted default
    constructor, something which was overlooked in r12-1665.  This patch
    also fixes a couple of other issues with the new split_view as reported
    in the PR.

            PR libstdc++/101214

    libstdc++-v3/ChangeLog:

            * include/std/ranges (split_view::split_view): Use std::move.
            (split_view::_Iterator::_Iterator): Remove redundant
            default_initializable constraint.
            (split_view::_Sentinel::_Sentinel): Declare.
            * testsuite/std/ranges/adaptors/split.cc (test02): New test.

[Bug libstdc++/101214] ranges::split_view​::​sentinel lacks default constructor

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101214

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
   Target Milestone|---                         |12.0
         Resolution|---                         |FIXED

--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for GCC 12.