(* Lemma headptr_field_compatible' {cs: compspecs}: forall t p, headptr p -> legal_alignas_type t = true -> legal_cosu_type t = true -> sizeof t < Ptrofs.modulus -> complete_type cenv_cs t = true -> field_compatible t nil p. *)

Lemma data_at_type_changable {cs}: forall (sh: Share.t) (t1 t2: type) v1 v2,
t1 = t2 ->
JMeq v1 v2 ->
@data_at cs sh t1 v1 = data_at sh t2 v2.