third_party/rust/futures/tests/try_join.rs


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35

#![deny(unreachable_code)]

use futures::{executor::block_on, try_join};

// TODO: This abuses https://github.com/rust-lang/rust/issues/58733 in order to
// test behavior of the `try_join!` macro with the never type before it is
// stabilized. Once `!` is again stabilized this can be removed and replaced
// with direct use of `!` below where `Never` is used.
trait MyTrait {
    type Output;
}
impl<T> MyTrait for fn() -> T {
    type Output = T;
}
type Never = <fn() -> ! as MyTrait>::Output;

#[test]
fn try_join_never_error() {
    block_on(async {
        let future1 = async { Ok::<(), Never>(()) };
        let future2 = async { Ok::<(), Never>(()) };
        try_join!(future1, future2)
    })
    .unwrap();
}

#[test]
fn try_join_never_ok() {
    block_on(async {
        let future1 = async { Err::<Never, ()>(()) };
        let future2 = async { Err::<Never, ()>(()) };
        try_join!(future1, future2)
    })
    .unwrap_err();
}