[Bug c++/100205] [11/12 Regression] error: invalid use of non-static data member

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100205

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Reduced:

struct coordinate_matrix {
  using index_t = unsigned;
  struct convert_to_matrix_coordinate {
    index_t column_id;
  };
  index_t column_id;

  // does not work
  using value_type2 = decltype(convert_to_matrix_coordinate{column_id});

  // does work
  using value_type5 = decltype(column_id);
};