5 fn id(x: isize) -> isize {
10 let mut vec: Vec<isize> = vec![3, 6, 1, 2, 5];
14 vec.sort_by_key(|&a| (a + 5).abs());
15 vec.sort_unstable_by_key(|&a| id(-a));
17 vec.sort_by_key(|&b| Reverse(b));
18 vec.sort_by_key(|&b| Reverse((b + 5).abs()));
19 vec.sort_unstable_by_key(|&b| Reverse(id(-b)));
20 // Negative examples (shouldn't be changed)
22 vec.sort_by(|a, b| (b - a).cmp(&(a - b)));
23 vec.sort_by(|_, b| b.cmp(&5));
24 vec.sort_by(|_, b| b.cmp(c));
25 vec.sort_unstable_by(|a, _| a.cmp(c));