1 use std::fmt; 2 3 #[derive(Debug)] 4 /// An error that can never occur. 5 pub enum Never {} 6 7 impl fmt::Display for Never { fmt(&self, _: &mut fmt::Formatter) -> fmt::Result8 fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result { 9 match *self {} 10 } 11 } 12 13 impl std::error::Error for Never {} 14