plpgsql - DECLARE - cannot to use %TYPE or %ROWTYPE for composite types

Hi,

We cannot to declare variable with referenced type on other composite
variable. This limit is probably artificial, because any composite type is
any type too in PostgreSQL.

The issue:

referencing on composite variables doesn't work

do $$ declare x int; y x%type; begin end; $$; -- ok
do $$ declare x pg_class; y x%type; begin end; $$; -- invalid type name
"x%type"
do $$ declare x pg_class; y x%rowtype; begin end; $$; -- relation "x" does
not exist

The %ROWTYPE needs a record in pg_class. Probably we should not to change
it. The change can bring a compatibility issues. So there are two
possibilities:

1. %TYPE can be used for any kind of variables. This behave will be
consistent with polymorphic parameters - we have "anyelement", and we have
not "anyrow".

2. introduce new keyword - %RECTYPE .. it can work, but there will be gap
between polymorphic parameters.

Comments, notices?

Regards

Pavel