[Bug libstdc++/120914] [C++26] P3029R1Better mdspan's CTAD

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120914

--- Comment #1 from Tomasz Kamiński <tkaminsk at gcc dot gnu.org> ---
We want to implement span changes as DR for C++20, and mdspan for C++23.