[Bug c++/65370] [5 Regression] rejects valid code on powerpc64le-linux-gnu

[doko at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65370

--- Comment #1 from Matthias Klose <doko at gcc dot gnu.org> ---
reduced test case:

namespace Parma_Polyhedra_Library {
class NNC_Polyhedron;
enum Complexity_Class { ANY_COMPLEXITY };
template <typename PSET> class Pointset_Powerset;
}
template <typename PSET> class Parma_Polyhedra_Library::Pointset_Powerset {
  template <typename QH>
  Pointset_Powerset(const Pointset_Powerset<QH> &,
                    Complexity_Class = ANY_COMPLEXITY);
};

namespace Parma_Polyhedra_Library {
template <>
template <typename QH>
Pointset_Powerset<NNC_Polyhedron>::Pointset_Powerset(
    const Pointset_Powerset<QH> &, Complexity_Class);
}