julius(dot)tuskenis(at)gmail(dot)com writes:
> The problem is with the composite types that have composite types in them.
> In cases then a subtype has all NULL fields the type is still evaluated NOT
> NULL.
Yeah, it's not recursive. We concluded that that's correct per the
text of the SQL standard. See discussion here:
https://www.postgresql.org/message-id/flat/20160708024746.1410.57282%40wrigleys.postgresql.org
regards, tom lane