create user test password 'test';
commit;

execute block
  returns (o_att_id int, o_user varchar(32))
as
begin
  o_att_id = CURRENT_CONNECTION;
  o_user = CURRENT_USER;
  suspend;

  -- should use current connection
  execute statement 'select CURRENT_CONNECTION, CURRENT_USER from rdb$database'
    into :o_att_id, :o_user;
  suspend;

  -- should use distinct connection
  execute statement 'select CURRENT_CONNECTION, CURRENT_USER from rdb$database'
    as user 'test' password 'test'
    into :o_att_id, :o_user;
  suspend;
end

All 3 rows returns the same values while 3rd row must not return the same values as 1st and 2nd.