method vexpr e =
match e.enode with
Lval(Var vi', _off) ->
(match self#get_cur_iosh() with
Some iosh ->
let vido = RD.iosh_defId_find iosh defid in
let exists = match vido with Some _ -> true | None -> false in
if vi.vid = vi'.vid && exists
then (useList := sid::(!useList); DoChildren)
else DoChildren
| _ -> Cilmsg.fatal "useLister: no data for statement")
| _ -> DoChildren