Reassigning objects and dropping users

After assigning permissions and restricting access, it can happen that users will be dropped from the system. Unsurprisingly, the commands to do that are the DROP ROLE and DROP USER commands:

test=# h DROP ROLE 
Command:     DROP ROLE 
Description: remove a database role 
Syntax: 
DROP ROLE [ IF EXISTS ] name [, ...] 

Let us give it a try:

test=# DROP ROLE joe; 
ERROR:  role "joe" cannot be dropped because some objects  
     depend on it 
DETAIL:  target of policy joe_pol_3 on table t_person 
target of policy joe_pol_2 on table t_person 
target of policy joe_pol_1 on table t_person 
privileges for table t_person 
owner of table t_user 
owner of sequence t_user_id_seq 
owner of default privileges on new relations belonging to role joe  
     in schema public 
owner of table t_useful 

PostgreSQL will issue error messages because a user can only be removed if everything has been...