[Bug libstdc++/119163] New: std::equal cannot be used with debug mode iterators in constant expressions

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119163

            Bug ID: 119163
           Summary: std::equal cannot be used with debug mode iterators in
                    constant expressions
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---

// { dg-do compile { target c++20 } }
#define _GLIBCXX_DEBUG
#include <vector>
#include <algorithm>
constexpr bool f()
{
  std::vector<char> v;
  return std::equal(v.begin(), v.end(), v.begin(), v.end());
}
static_assert( f() );


bits/stl_algobase.h:1717:7: error: call to non-'constexpr' function 'bool
__gnu_debug::__valid_range(const _Safe_iterator<_Iterator, _Sequence,
_Category>&, const _Safe_iterator<_Iterator, _Sequence, _Category>&) [with
_Iterator = __gnu_cxx::__normal_iterator<char*, std::__cxx1998::vector<char,
std::allocator<char> > >; _Sequence = std::__debug::vector<char>; _Category =
std::random_access_iterator_tag]'
 1717 |       __glibcxx_requires_valid_range(__first1, __last1);
      |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~