Fix size check in memory_copying

Co-authored-by: Michael Schwarz <[email protected]>

src/analyses/base.ml

@@ -2139,21 +2139,16 @@ struct
       in
       let dest_size_equal_n =
         match dest_size, n_intdom with
-        | `Top, `Top -> true
-        | `Bot, `Bot -> true
         | `Lifted ds, `Lifted n ->
           let casted_ds = ID.cast_to (Cilfacade.ptrdiff_ikind ()) ds in
           let casted_n = ID.cast_to (Cilfacade.ptrdiff_ikind ()) n in
           let ds_eq_n =
             begin try ID.eq casted_ds casted_n
-              with IntDomain.ArithmeticOnIntegerBot _ -> ID.bot_of @@ Cilfacade.ptrdiff_ikind ()
+              with IntDomain.ArithmeticOnIntegerBot _ -> ID.top_of @@ Cilfacade.ptrdiff_ikind ()
             end
           in
-          begin match ID.to_bool ds_eq_n with
-            | Some b -> b
-            | None -> false
-          end
-        | _, _ -> false
+          Option.value ~default:false ID.to_bool ds_eq_n
+        | _ -> false
       in
       let dest_a, dest_typ = addr_type_of_exp dst in
       let src_lval = mkMem ~addr:(Cil.stripCasts src) ~off:NoOffset in