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Commit | Line | Data |
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0731742a XL |
1 | #![deny(unused_must_use)] |
2 | #![feature(arbitrary_self_types, futures_api)] | |
3 | ||
4 | use std::iter::Iterator; | |
5 | use std::future::Future; | |
6 | ||
7 | use std::task::{Poll, LocalWaker}; | |
8 | use std::pin::Pin; | |
9 | use std::unimplemented; | |
10 | ||
11 | struct MyFuture; | |
12 | ||
13 | impl Future for MyFuture { | |
14 | type Output = u32; | |
15 | ||
16 | fn poll(self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<u32> { | |
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() { | |
42 | iterator(); //~ ERROR unused implementer of `std::iter::Iterator` that must be used | |
43 | future(); //~ ERROR unused implementer of `std::future::Future` that must be used | |
44 | square_fn_once(); //~ ERROR unused implementer of `std::ops::FnOnce` that must be used | |
45 | square_fn_mut(); //~ ERROR unused implementer of `std::ops::FnMut` that must be used | |
46 | square_fn(); //~ ERROR unused implementer of `std::ops::Fn` that must be used | |
47 | } |