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Commit | Line | Data |
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0731742a | 1 | #![deny(unused_must_use)] |
48663c56 | 2 | #![feature(arbitrary_self_types)] |
0731742a XL |
3 | |
4 | use std::iter::Iterator; | |
5 | use std::future::Future; | |
6 | ||
532ac7d7 | 7 | use std::task::{Context, Poll}; |
0731742a XL |
8 | use std::pin::Pin; |
9 | use std::unimplemented; | |
10 | ||
11 | struct MyFuture; | |
12 | ||
13 | impl Future for MyFuture { | |
14 | type Output = u32; | |
15 | ||
532ac7d7 | 16 | fn poll(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<u32> { |
0731742a XL |
17 | Poll::Pending |
18 | } | |
19 | } | |
20 | ||
21 | fn iterator() -> impl Iterator { | |
22 | std::iter::empty::<u32>() | |
23 | } | |
24 | ||
25 | fn future() -> impl Future { | |
26 | MyFuture | |
27 | } | |
28 | ||
29 | fn square_fn_once() -> impl FnOnce(u32) -> u32 { | |
30 | |x| x * x | |
31 | } | |
32 | ||
33 | fn square_fn_mut() -> impl FnMut(u32) -> u32 { | |
34 | |x| x * x | |
35 | } | |
36 | ||
37 | fn square_fn() -> impl Fn(u32) -> u32 { | |
38 | |x| x * x | |
39 | } | |
40 | ||
41 | fn main() { | |
1b1a35ee XL |
42 | iterator(); //~ ERROR unused implementer of `Iterator` that must be used |
43 | future(); //~ ERROR unused implementer of `Future` that must be used | |
44 | square_fn_once(); //~ ERROR unused implementer of `FnOnce` that must be used | |
45 | square_fn_mut(); //~ ERROR unused implementer of `FnMut` that must be used | |
46 | square_fn(); //~ ERROR unused implementer of `Fn` that must be used | |
0731742a | 47 | } |