-- Testing cross-types compatibility
SELECT (0::uint8)::numeric;
 numeric 
---------
       0
(1 row)

SELECT ('0'::numeric)::uint8;
 uint8 
-------
 0
(1 row)

SELECT ('18446744073709551616'::numeric)::uint8;
ERROR:  uint8 out of range
SELECT (0::uint8)::json;
 json 
------
 0
(1 row)

SELECT json_build_object('some', 0::uint8);
 json_build_object 
-------------------
 {"some" : 0}
(1 row)

SELECT ('0'::json)::uint8;
 uint8 
-------
 0
(1 row)

SELECT (0::uint8)::jsonb;
 jsonb 
-------
 0
(1 row)

SELECT jsonb_build_object('some', 0::uint8);
 jsonb_build_object 
--------------------
 {"some": 0}
(1 row)

SELECT ('0'::jsonb)::uint8;
 uint8 
-------
 0
(1 row)

SELECT ('"abc"'::jsonb)::uint8;
ERROR:  cannot cast jsonb string to type uint8