(* solve list equations *)
(* interpreted functions : Zlength app list_repeat / Zrepeat map sublist upd_Znth -> sublist Znth *)
Definition data_subsume {cs : compspecs} (t : type) (x y : reptype t) : Prop :=
forall sh p, data_at sh t x p |-- data_at sh t y p.
Ltac apply_list_ext :=
first
[ apply data_subsume_array_ext;
only 1, 2 : Zlength_solve
| match goal with |- @eq ?list_A _ _ =>
match eval compute in list_A with list ?A =>
apply (@Znth_eq_ext A ltac:(auto with typeclass_instances))
end
end;
only 1 : Zlength_solve
];
autorewrite with Zlength;
intros.

Lemma rangei_shift' : forall (lo hi lo' hi' : Z) (P Q : Z -> Prop),
let offset := lo' - lo in
offset = hi' - hi ->
rangei lo' hi' (fun i => Q i <-> P (i - offset)) ->
rangei lo hi P <-> rangei lo' hi' Q.