https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120239
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Oh actually we already do the same, but only with -Wall:
foo.cc: In function ‘void f()’:
foo.cc:3:6: error: expected ‘;’ before ‘}’ token
3 | { 0 };
| ^~
| ;
foo.cc:3:5: warning: statement has no effect [-Wunused-value]
3 | { 0 };
| ^
