rust/src/test/compile-fail/uninhabited-patterns.rs
2017-02-04 16:27:45 +08:00

58 lines
1.4 KiB
Rust

// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(box_patterns)]
#![feature(slice_patterns)]
#![feature(box_syntax)]
#![feature(never_type)]
#![deny(unreachable_patterns)]
mod foo {
pub struct SecretlyEmpty {
_priv: !,
}
}
struct NotSoSecretlyEmpty {
_priv: !,
}
fn foo() -> Option<NotSoSecretlyEmpty> {
None
}
fn main() {
let x: &[!] = &[];
match x {
&[] => (),
&[..] => (), //~ ERROR unreachable pattern
};
let x: Result<Box<NotSoSecretlyEmpty>, &[Result<!, !>]> = Err(&[]);
match x {
Ok(box _) => (), //~ ERROR unreachable pattern
Err(&[]) => (),
Err(&[..]) => (), //~ ERROR unreachable pattern
}
let x: Result<foo::SecretlyEmpty, Result<NotSoSecretlyEmpty, u32>> = Err(Err(123));
match x {
Ok(_y) => (),
Err(Err(_y)) => (),
Err(Ok(_y)) => (), //~ ERROR unreachable pattern
}
while let Some(_y) = foo() {
//~^ ERROR unreachable pattern
}
}