On Thu, 11 Sep 2025, Alejandro Colomar wrote: > Warn about this: > > void f(int x; int x; int x); > > This would allow eventually adding another semicolon in function > prototypes to separate a different feature.
I don't think that's a plausible future addition. The small visual difference between comma and semicolon is one of the reasons people have given for objecting to this feature; adding extra features with multiple semicolons seems even more confusing, quite apart from being incompatible with the existing extension. > So, make multiple lists of forward declarations of parameters > obsolescent, and produce a new diagnostic, > -Wmultiple-parameter-fwd-decl-lists, which diagnoses uses of this > obsolescent syntax. I'm dubious of obsolescence here. Restricting to a single forward declaration list is one of many possible design choices for a subset of the feature to consider for the standard; it's a reasonable subset choice, but hardly a unique one. If the feature were accepted into C2y with that particular subset, my inclination would be that cases outside that subset (i.e. multiple forward declaration lists) would then (continue to) get a pedwarn-if-pedantic, rather than any stronger form of obsolescence such as warning with -Wextra. Having an additional option for this particular case is reasonable enough; it's treating it as obsolesence or including it in -Wextra that seems questionable. -- Joseph S. Myers josmy...@redhat.com
