Currently, it's only supported for mapped super class but we could definitely support it for TABLE_PER_CLASS too.

See https://github.com/hibernate/hibernate-orm/commit/2dd008adb7e39a8513a027582ba8a55ee7b4eedb for when we added a warning about it not being supported.

Note that we still won't support SINGLE_TABLE and JOINED as it makes no sense.