(* Lemma stronger_data_at_rec_derives: forall sh t v0 v1 pos p, legal_alignas_type t = true -> (alignof t | pos) -> v0 >>> v1 -> field_compatible t nil (offset_val (Int.repr pos) p) -> data_at_rec sh type_id_env.empty_ti t pos v0 p |-- data_at_rec sh type_id_env.empty_ti t pos v1 p. *)
(* Lemma stronger_data_at_rec_nested_field_derives: forall sh t gfs t0 v0 v1 p, legal_alignas_type t = true -> nested_field_type2 t gfs = t0 -> legal_nested_field t gfs -> v0 >>> v1 -> size_compatible t p -> align_compatible t p -> data_at_rec sh type_id_env.empty_ti t0 (nested_field_offset2 t gfs) v0 p |-- data_at_rec sh type_id_env.empty_ti t0 (nested_field_offset2 t gfs) v1 p. *)

Lemma eq_rect_r_data_equal: forall {t1 t2} v0 v1 (H: t1 = t2),
v0 === v1 ->
eq_rect_r reptype v0 H === eq_rect_r reptype v1 H.