[Bug c++/126599] [reflection] display_string_of(nullptr-pointer-to-data-member) is "-1"

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126599

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 65224
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=65224&action=edit
gcc17-pr126599.patch

Untested fix.