Section GET_CO.
Context {cs: compspecs}.
Open Scope Z.
Definition co_default (s: struct_or_union): composite.
apply (Build_composite s nil noattr 0 1 0).
+ intro. inv H.
+ exists 0%nat; auto.
+ exists 0; auto.
Defined.
Definition get_co id :=
match cenv_cs ! id with
| Some co => co
| _ => co_default Struct
end.
End GET_CO.

Lemma co_sizeof_get_co_change_composite {cs_from cs_to} {CCE: change_composite_env cs_from cs_to}: forall id,
match (coeq cs_from cs_to) ! id with
| Some b => test_aux cs_from cs_to b id
| None => false
end = true ->
co_sizeof (@get_co cs_from id) = co_sizeof (@get_co cs_to id).