Listing:

    1  MODULE PBadFwd;
    2  VAR ExitCode : INTEGER;
    3  PROCEDURE P(a : INTEGER) : INTEGER;
    4  FORWARD;
    5  PROCEDURE P(a, b : INTEGER) : INTEGER;
*****                                ^ procedure forward mismatch or missing body
    6  BEGIN
    7    RETURN a + b
    8  END P;
    9  BEGIN
   10    ExitCode := P(1, 2)
   11  END PBadFwd.

    1 error