create schema signed_unsigned_cast;
set current_schema to 'signed_unsigned_cast';
select cast(1-2 as unsigned);
        uint8         
----------------------
 18446744073709551615
(1 row)

select cast(3-5 as signed);
 int8 
------
   -2
(1 row)

select cast(cast(1 - 5 as signed) as unsigned);
        uint8         
----------------------
 18446744073709551612
(1 row)

select cast(cast(1 + 5 as unsigned) as signed);
 int8 
------
    6
(1 row)

drop schema signed_unsigned_cast cascade;
reset current_schema;