UNREGISTERED_POLYMORPHIC_CAST_EXCEPTION thrown on save for polymorphic types using split save/load member functions

[amesgames]

Are split save/load member functions supported for polymorphic types?

To demonsrate, I modified the polymorphic unittest so that PolyDerived looks like the following:

struct PolyDerived : PolyBase
{
  PolyDerived() {}
  PolyDerived( int xx, float yy, bool aa, double bb ) :
    PolyBase( xx, yy ), a(aa), b(bb) {}
  virtual ~PolyDerived() {}

  bool a;
  double b;

  // template <class Archive>
  // void serialize( Archive & ar )
  // {
  //   ar( cereal::base_class<PolyBase>( this ),
  //       a, b );
  // }

  template<class Archive>
  void save( Archive & ar ) const
  {
    ar( cereal::base_class<PolyBase>( this ),
        a, b );
  }

  template<class Archive>
  void load( Archive & ar )
  {
    ar( cereal::base_class( this ),
        a, b );
  }

  bool operator==( PolyDerived const & other ) const
  {
    return PolyBase::operator==( other ) && a == other.a && std::abs(b - other.b)