(* Test: twisted, mutually recursive types *)

MODULE Main;

TYPE  (* T1 == T2 == T3 == T4 == U4 *)
   T1 = REF T1;
   T2 = REF REF T2;
   T3 = REF REF REF T3;
   T4 = REF U4;   U4 = REF T4;

TYPE  (* R1 == R2 *)
   R1 = RECORD  i: INTEGER;  j: T3;  k: X2  END;
   R2 = RECORD  i: INTEGER;  j: T4;  k: X1  END;

TYPE  (* X1 == X2 *)
   X1 = REF R1;
   X2 = REF R2;


PROCEDURE P (VAR x: X1) =
  BEGIN
  END P;

VAR x2: X2;

BEGIN
  P (x2);
END Main.