Re: BUG #5314: Error in nested composite types in plpgsql. - Mailing list pgsql-bugs

2010/2/10 Oleg Serov <serovov@gmail.com>:
> Somebody will fix this bug or not?

I'm not sure whether this is a bug.  This is an explicit cast:

SELECT '(1,)'::bug_level_one;

But I think this is an implicit cast:

SELECT bug_procedure('(1,)');

I'm not totally sure of the details, but implicit, assignment, and
explicit casts are documented to have different semantics:

http://www.postgresql.org/docs/current/static/sql-createcast.html

...Robert