Hint Resolve legal_nested_field0_field.

(* Lemma nested_field_offset_type_divide: forall gfs t, legal_alignas_type t = true -> legal_nested_field t gfs -> (alignof (nested_field_type t gfs) | nested_field_offset t gfs).  Lemma nested_field_offset_type_divide0: forall gfs t, legal_alignas_type t = true -> legal_nested_field0 t gfs -> (alignof (nested_field_type t gfs) | nested_field_offset t gfs). *)
Lemma gfield_offset_in_range: forall t gf,
legal_field t gf ->
complete_legal_cosu_type t = true ->
0 <= gfield_offset t gf /\ gfield_offset t gf + sizeof (gfield_type t gf) <= sizeof t.