Fix a pretty printing error for ground types (the negative part was not shown...

Fix a pretty printing error for ground types (the negative part was not shown due to "worth_complement" being called twice).

types/types.ml

@@ -1836,8 +1836,6 @@ struct
       end with Not_found ->
         if d.absent then
           alloc [Abs (prepare ({d with absent=false}))]
-        else if worth_complement d then
-          alloc [Neg (prepare (neg d))]
         else
           let slot = alloc [] in
           if not (worth_abbrev d) then
@@ -2124,11 +2122,7 @@ struct
                   List.map (fun x -> (Atomic x)) l
                 )  tt.abstract u_acc
                 in
-
-                let u_acc =
-                  if tt.absent then (Atomic (fun ppf -> Format.fprintf ppf "#ABSENT")) :: u_acc
-                  else u_acc
-                in
+                if tt.absent then assert false; (* is taken care of at the top *)
                 print_topvars positive u_acc
           in
           let all_printed =