let is_included t1 t2 =
(* (t2.initialized ==> t1.initialized) &&
(t2.no_escaping_adr ==> t1.no_escaping_adr) &&
V.is_included t1.v t2.v
*)
let flags1 = get_flags t1 in
let flags2 = get_flags t2 in
(lnot flags2) lor flags1 = -1 &&
V.is_included (get_v t1) (get_v t2)