use std::fmt;
use std::error;
pub enum Void {}
impl fmt::Debug for Void {
fn fmt( &self, _: &mut fmt::Formatter ) -> Result< (), fmt::Error > {
unreachable!();
}
}
impl fmt::Display for Void {
fn fmt( &self, _: &mut fmt::Formatter ) -> Result< (), fmt::Error > {
unreachable!();
}
}
impl error::Error for Void {
fn description( &self ) -> &str {
unreachable!();
}
}