-- Testing cross-types compatibility
SELECT (0::uint1)::numeric;
 numeric 
---------
       0
(1 row)

SELECT ('0'::numeric)::uint1;
 uint1 
-------
 0
(1 row)

SELECT ('256'::numeric)::uint1;
ERROR:  uint1 out of range
SELECT (0::uint1)::json;
 json 
------
 0
(1 row)

SELECT json_build_object('some', 0::uint1);
 json_build_object 
-------------------
 {"some" : 0}
(1 row)

SELECT ('0'::json)::uint1;
 uint1 
-------
 0
(1 row)

SELECT (0::uint1)::jsonb;
 jsonb 
-------
 0
(1 row)

SELECT jsonb_build_object('some', 0::uint1);
 jsonb_build_object 
--------------------
 {"some": 0}
(1 row)

SELECT ('0'::jsonb)::uint1;
 uint1 
-------
 0
(1 row)

SELECT ('"abc"'::jsonb)::uint1;
ERROR:  cannot cast jsonb string to type uint1