1 use std::fmt; 2 #[derive(Debug)] 3 /// An error that can never occur. 4 pub enum Never {} 5 6 impl fmt::Display for Never { fmt(&self, _: &mut fmt::Formatter) -> fmt::Result7 fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result { 8 match *self {} 9 } 10 } 11 12 impl std::error::Error for Never {} 13