2 #![warn(clippy::iter_on_empty_collections)]
3 #![allow(clippy::iter_next_slice, clippy::redundant_clone)]
6 assert_eq!([].into_iter().next(), Option::<i32>::None);
7 assert_eq!([].iter_mut().next(), Option::<&mut i32>::None);
8 assert_eq!([].iter().next(), Option::<&i32>::None);
9 assert_eq!(None.into_iter().next(), Option::<i32>::None);
10 assert_eq!(None.iter_mut().next(), Option::<&mut i32>::None);
11 assert_eq!(None.iter().next(), Option::<&i32>::None);
13 // Don't trigger on non-iter methods
14 let _: Option<String> = None.clone();
15 let _: [String; 0] = [].clone();
17 // Don't trigger on match or if branches
23 let _ = if false { ["test"].iter() } else { [].iter() };
26 macro_rules! in_macros {
28 assert_eq!([].into_iter().next(), Option::<i32>::None);
29 assert_eq!([].iter_mut().next(), Option::<&mut i32>::None);
30 assert_eq!([].iter().next(), Option::<&i32>::None);
31 assert_eq!(None.into_iter().next(), Option::<i32>::None);
32 assert_eq!(None.iter_mut().next(), Option::<&mut i32>::None);
33 assert_eq!(None.iter().next(), Option::<&i32>::None);
37 // Don't trigger on a `None` that isn't std's option
47 fn iter_mut(&mut self) {}
52 pub fn custom_option() {
61 custom_option::custom_option();