18 assert_eq!(size_of::<E>(), 1);
19 assert_eq!(size_of::<Option<E>>(), 1);
20 assert_eq!(size_of::<Result<E, ()>>(), 1);
21 assert_eq!(size_of::<Option<S>>(), size_of::<S>());
22 let enone = None::<E>;
23 let esome = Some(E::A);
24 if let Some(..) = enone {