3 #[derive(Copy, Clone, Debug, PartialEq)]
6 fn try_num(x: i32) -> Result<i32, BadNumErr> {
14 type ResOpt = Result<Option<i32>, BadNumErr>;
15 type OptRes = Option<Result<i32, BadNumErr>>;
18 let mut x: ResOpt = Ok(Some(5));
19 let mut y: OptRes = Some(Ok(5));
20 assert_eq!(x, y.transpose());
21 assert_eq!(x.transpose(), y);
25 assert_eq!(x, y.transpose());
26 assert_eq!(x.transpose(), y);
29 y = Some(Err(BadNumErr));
30 assert_eq!(x, y.transpose());
31 assert_eq!(x.transpose(), y);
33 let res: Result<Vec<i32>, BadNumErr> =
43 .filter_map(Result::transpose)
46 assert_eq!(res, Err(BadNumErr))