Section COMPOSITE_ENV.
Context {cs: compspecs}.
Ltac solve_field_offset_type i m :=
let H := fresh "H" in
let Hty := fresh "H" in
let Hofs := fresh "H" in
let t := fresh "t" in
let ofs := fresh "ofs" in
pose proof field_offset_field_type_match cenv_cs i m;
destruct (Ctypes.field_offset cenv_cs i m) as [ofs|?] eqn:Hofs, (Ctypes.field_type i m) as [t|?] eqn:Hty;
[clear H | inversion H | inversion H | clear H].

(* if sizeof Tvoid = 0, this lemma can be nicer. *)
Lemma sizeof_union_in_members: forall i m,
in_members i m ->
sizeof (field_type i m) <= sizeof_union cenv_cs m.