qapi: Tighten check whether implicit object type already exists

Entities with names starting with q_obj_ are implicit object types.
Therefore, QAPISchema._make_implicit_object_type()'s .lookup_entity()
can only return a QAPISchemaObjectType.  Assert that.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240315152301.3621858-25-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: John Snow <jsnow@redhat.com>
1 file changed