# let f a:t1 = match a with h::t -> let z = h+1 in () | [] -> ();;
Characters 13-62:
  let f a:t1 = match a with h::t -> let z = h+1 in () | [] -> ();;
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This expression has type unit but is here used with type
  t1 = (int * int) list
#