https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125643
--- Comment #1 from Drea Pinski <pinskia at gcc dot gnu.org> ---
We accept it only without -pedantic and then without -pedantic we warn about
it:
<source>: In function 'f':
<source>:1:10: warning: empty declaration
1 | void f() int; {
| ^~~
