https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80981
Markus Trippelsdorf <trippels at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
CC| |trippels at gcc dot gnu.org
Resolution|--- |INVALID
--- Comment #2 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
The error looks valid. Even clang rejects it when using a vanilla class a
(without template).
You need a forward declaration of void b() in this case.
