BUG #13053: type names pollute function name space

The following bug has been logged on the website:

Bug reference:      13053
Logged by:          Dwayne Towell
Email address:      dwayne.towell@gmail.com
PostgreSQL version: 9.2.10
Operating system:   CentOS
Description:

The following:

CREATE TYPE x AS (id int);
CREATE FUNCTION _x(text) RETURNS SETOF x AS $$ SELECT 1 WHERE $1='hi'; $$
LANGUAGE SQL;
SELECT _x('hi');

produces:

ERROR:  array value must start with "{" or dimension information
LINE 1: SELECT _x('hi');

Which seems wrong. Creating a type named 'x' should not preempt my function
by finding an auto created(?) conversion(?) function.