src/tools/clippy/src/docs/reversed_empty_ranges.txt

   1 ### What it does
   2 Checks for range expressions `x..y` where both `x` and `y`
   3 are constant and `x` is greater or equal to `y`.
   4
   5 ### Why is this bad?
   6 Empty ranges yield no values so iterating them is a no-op.
   7 Moreover, trying to use a reversed range to index a slice will panic at run-time.
   8
   9 ### Example
  10 ```
  11 fn main() {
  12     (10..=0).for_each(|x| println!("{}", x));
  13
  14     let arr = [1, 2, 3, 4, 5];
  15     let sub = &arr[3..1];
  16 }
  17 ```
  18 Use instead:
  19 ```
  20 fn main() {
  21     (0..=10).rev().for_each(|x| println!("{}", x));
  22
  23     let arr = [1, 2, 3, 4, 5];
  24     let sub = &arr[1..3];
  25 }
  26 ```