error[E0623]: lifetime mismatch --> $DIR/issue-17728.rs:15:28 | LL | fn attemptTraverse(&self, room: &Room, directionStr: &str) -> Result<&Room, &str> { | ----- ------------------- | | | this parameter and the return type are declared with different lifetimes... ... LL | Some(entry) => Ok(entry), | ^^^^^^^^^ ...but data from `room` is returned here error[E0308]: `match` arms have incompatible types --> $DIR/issue-17728.rs:109:14 | LL | / match to_parse { LL | | "w" | "west" => RoomDirection::West, LL | | "e" | "east" => RoomDirection::East, LL | | "n" | "north" => RoomDirection::North, ... | LL | | "down" => RoomDirection::Down, | | ------------------- this and all prior arms are found to be of type `RoomDirection` LL | | _ => None | | ^^^^ expected enum `RoomDirection`, found enum `Option` LL | | } | |_____- `match` arms have incompatible types | = note: expected enum `RoomDirection` found enum `Option<_>` error: aborting due to 2 previous errors Some errors have detailed explanations: E0308, E0623. For more information about an error, try `rustc --explain E0308`.