free c:channel.

event A.
event B(nat).

query event(A).
query i:nat; event(B(i)).

process
  in(c,i:nat);
  let j:nat suchthat j < i in
  event A;
  event B(j)

(* EXPECTPV
Error: < should be a predicate.
xtime: error in child process (status : 2)
END *)
