[Bug libstdc++/118395] New: Constructor of std::barrier is not constexpr

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118395

            Bug ID: 118395
           Summary: Constructor of std::barrier is not constexpr
           Product: gcc
           Version: 15.0
            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: ---

The C++20 standard says:

  constexpr explicit barrier(ptrdiff_t expected,
                             CompletionFunction f = CompletionFunction());

But we say:

      explicit
      barrier(ptrdiff_t __count, _CompletionF __completion = _CompletionF())