https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72763
Jason Merrill <jason at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |INVALID
--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> ---
This looks well-formed to me; we don't substitute into C<T> until we need D to
be complete, which we don't when we're just using A<int>. If you change the
declaration of a to
A<int>::D a;
then you get the error you're expecting.
