Listing:

    1  MODULE OBadOpen;
    2  VAR a : ARRAY [1 .. 3] OF INTEGER;
    3  PROCEDURE P(VAR x : ARRAY OF INTEGER);
    4  BEGIN
    5  END P;
    6  PROCEDURE Q(VAR y : ARRAY OF INTEGER);
    7  BEGIN
    8    P(y)
*****      ^ invalid procedure call
    9  END Q;
   10  BEGIN
   11    P(a)
   12  END OBadOpen.

    1 error