[Bug c++/123641] New: [reflection] members_of and friend class

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123641

            Bug ID: 123641
           Summary: [reflection] members_of and friend class
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mpolacek at gcc dot gnu.org
  Target Milestone: ---

This should pass:

```
#include <meta>
using namespace std::meta;

namespace N {
  void B ();
  struct A {
    int m;
    friend class B;
  };
}
constexpr access_context uctx = access_context::unchecked ();
static_assert (members_of (^^N, uctx).size () == 2);
```

but doesn't because namespace_members_of doesn't skip STAT_TYPE_HIDDEN_P.