Postgres 13

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

create procedure do_stuff()
as
$$
begin
  raise notice 'Procedure called';
end;
$$
language plpgsql;
do
$$
begin
  call do_stuff();
end;
$$
;  
do
$$
begin
  perform do_stuff();
end;
$$
;  
ERROR:  do_stuff() is a procedure
LINE 1: SELECT do_stuff()
               ^
HINT:  To call a procedure, use CALL.
QUERY:  SELECT do_stuff()
CONTEXT:  PL/pgSQL function inline_code_block line 3 at PERFORM