For example:
CREATE TYPE public.my_type AS ENUM('a', 'b', 'c');
SELECT 'a'::public.my_type;
The select statement produces a parse error:
Syntax Error: Unexpected "."
Was expecting to see: ...
--> undefined:3:15
|
3 | SELECT 'a'::public.my_type;
| ^
Similarly in CREATE TABLE:
CREATE TABLE foo (id public.my_type);