Postgresql warning: type reference X converted to Y (SQL State: 00000 - Error Code: 0) When I execute:

CREATE VIEW foreign_keys AS
SELECT
    tc.table_name, kcu.column_name, ccu.table_name AS foreign_table_name,
    ccu.column_name AS foreign_column_name
FROM
    information_schema.table_constraints AS tc, information_schema.key_column_usage AS kcu,
    information_schema.constraint_column_usage AS ccu
WHERE
    tc.constraint_type = 'FOREIGN KEY' AND tc.constraint_name = kcu.constraint_name AND
    ccu.constraint_name = tc.constraint_name;

CREATE FUNCTION GetPermissionColumns() RETURNS TABLE(column_name foreign_keys.column_name%TYPE)
    AS $$
BEGIN
    RETURN QUERY SELECT column_name FROM foreign_keys WHERE table_name = tg_table_name AND
        foreign_table_name = 'permission';
END;
$$ LANGUAGE plpgsql;


under Postgresql 9.3 I get the following warning message:

type reference foreign_keys.column_name%TYPE converted to information_schema.sql_identifier (SQL State: 00000 - Error Code: 0)

What am I doing wrong and how can I correct it?
Answering my own question...

It turns out this is harmless INFO-level logging: https://stackoverflow.com/a/3531274/14731