Definition struct_value_fits_aux (m m0: members)
(P: ListType (map (fun it => reptype (field_type (fst it) m0) -> Prop) m))
(v: compact_prod (map (fun it => reptype (field_type (fst it) m0)) m)) : Prop.

Lemma union_value_fits_aux_spec: forall m m0 v P,
union_value_fits_aux m m0
(ListTypeGen
(fun it => reptype (field_type (fst it) m0) -> Prop)
P m) v =
union_Prop m P v.