Fixed #22250 -- regression in gis compiler for non-concrete fields

        seen = self.query.included_inherited_models.copy()

        if start_alias:

            seen[None] = start_alias

        for field, model in opts.get_fields_with_model():

        for field, model in opts.get_concrete_fields_with_model():

            if from_parent and model is not None and issubclass(from_parent, model):

                # Avoid loading data for already loaded parents.

                continue

        self.assertEqual(True, union.equals_exact(u2, tol))

        qs = City.objects.filter(name='NotACity')

        self.assertEqual(None, qs.unionagg(field_name='point'))

    def test_non_concrete_field(self):

        pkfield = City._meta.get_field_by_name('id')[0]

        orig_pkfield_col = pkfield.column

        pkfield.column = None

        try:

            list(City.objects.all())

        finally:

            pkfield.column = orig_pkfield_col