On Sun, May 1, 2022 at 9:57 AM Abdullah Qasim via Std-Proposals <std-proposals@lists.isocpp.org> wrote:

 int func (int var, explicit int select_menu)

Beside the font and ! and CAPS LOCK I really like your attempt to make code less buggy.
Unfortunately/fortunately I am not sure it requires language changes,
AFAIK what you want is achievable with -Wconversion , I am a bit disappointed nobody mentioned it already(or am I missing the point of the discussion?).