[Bug c/83559] [8 regression] -Wsuggest-attribute=const conflicts with -Wattributes warning about const attribute on function returning void

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83559

--- Comment #7 from Martin Sebor <msebor at gcc dot gnu.org> ---
One other note: The goal is that new warning will expose opportunities to
improve code (if not fix bugs).  I don't know of a valid use case for a
function to be const and return void but if there is one I'd be interested in
hearing about it.