[Bug libstdc++/116399] New: C++26 text_encoding​::​aliases_view is not default-constructible

[hewillk at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116399

            Bug ID: 116399
           Summary: C++26 text_encoding​::​aliases_view is not
                    default-constructible
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hewillk at gmail dot com
  Target Milestone: ---

text.encoding.aliases] indicates that text_encoding::aliases_view is an empty
struct, which suggests it is default-constructible.

However, the private custom constructors in the libstdc++ implementation make
it not so:

#include <text_encoding>

std::text_encoding::aliases_view av{};

https://godbolt.org/z/MahWfeW81

Not sure if this is LWG-worthy.