#![feature(box_patterns)] #![feature(never_type)] #![feature(exhaustive_patterns)] #![deny(unreachable_patterns)] mod foo { pub struct SecretlyEmpty { _priv: !, } } struct NotSoSecretlyEmpty { _priv: !, } fn foo() -> Option { None } fn main() { let x: &[!] = &[]; match x { &[] => (), &[..] => (), //~ ERROR unreachable pattern }; let x: Result, &[Result]> = Err(&[]); match x { Ok(box _) => (), //~ ERROR unreachable pattern Err(&[]) => (), Err(&[..]) => (), //~ ERROR unreachable pattern } let x: Result> = Err(Err(123)); match x { Ok(_y) => (), Err(Err(_y)) => (), Err(Ok(_y)) => (), //~ ERROR unreachable pattern } while let Some(_y) = foo() { //~^ ERROR unreachable pattern } }