Обсуждение: table types/check constraints

In my gripe/suggestion here:
http://archives.postgresql.org/pgsql-hackers/2008-12/msg00642.php

I noted that it might be nice to handle check constraints over
composite types.  It turns out that table check constraints are not
enforced during casts:

postgres=# create table foo(f1 int, f2 int, check(f1 != f2));
postgres=# select (1,1)::foo; row
-------(1,1)
(1 row)

Should the be?  I've been thinking about how to marry tables and
composite types.

merlin