CREATE GLOBAL TEMPORARY TABLE NEW_TABLE (
    DT  DATE
) ON COMMIT DELETE ROWS;

create procedure test_debug
returns (dt date)
as
declare variable d integer;
declare variable cdate date;
begin
  cdate = current_date;
  insert into new_table
  select :cdate from rdb$database;
  d=1;
  insert into new_table
  select :cdate+:d from rdb$database;
  insert into new_table
  select :cdate-:d from rdb$database;
end^

Overflow occurred during data type conversion.
conversion error from string "44536".
----------------------------------------------
SQLCODE: -413
SQLSTATE: 22018
GDSCODE: 335544334