try if-let

src/ship/ship.rs

@@ -336,9 +336,9 @@ impl<EG: EntityGateway> ServerState for ShipServerState<EG> {
 
         let pkt = match self.client_location.get_area(id).unwrap() {
             RoomLobby::Room(room) => {
-                self.client_location.get_client_neighbors(id).map(|x| if x.len() == 0 {
-                    self.rooms[room.0] = None
-                });
+                if let 0 = neighbors.len() {
+                    self.rooms[room.0] = None;
+                }
                 let leader = self.client_location.get_room_leader(room).unwrap();
                 SendShipPacket::LeaveRoom(LeaveRoom::new(client.local_client.id(), leader.local_client.id()))
             },