src/tools/clippy/tests/ui/unnecessary_fold.fixed

   1 //@run-rustfix
   2
   3 #![allow(dead_code)]
   4
   5 /// Calls which should trigger the `UNNECESSARY_FOLD` lint
   6 fn unnecessary_fold() {
   7     // Can be replaced by .any
   8     let _ = (0..3).any(|x| x > 2);
   9     // Can be replaced by .all
  10     let _ = (0..3).all(|x| x > 2);
  11     // Can be replaced by .sum
  12     let _: i32 = (0..3).sum();
  13     // Can be replaced by .product
  14     let _: i32 = (0..3).product();
  15 }
  16
  17 /// Should trigger the `UNNECESSARY_FOLD` lint, with an error span including exactly `.fold(...)`
  18 fn unnecessary_fold_span_for_multi_element_chain() {
  19     let _: bool = (0..3).map(|x| 2 * x).any(|x| x > 2);
  20 }
  21
  22 /// Calls which should not trigger the `UNNECESSARY_FOLD` lint
  23 fn unnecessary_fold_should_ignore() {
  24     let _ = (0..3).fold(true, |acc, x| acc || x > 2);
  25     let _ = (0..3).fold(false, |acc, x| acc && x > 2);
  26     let _ = (0..3).fold(1, |acc, x| acc + x);
  27     let _ = (0..3).fold(0, |acc, x| acc * x);
  28     let _ = (0..3).fold(0, |acc, x| 1 + acc + x);
  29
  30     // We only match against an accumulator on the left
  31     // hand side. We could lint for .sum and .product when
  32     // it's on the right, but don't for now (and this wouldn't
  33     // be valid if we extended the lint to cover arbitrary numeric
  34     // types).
  35     let _ = (0..3).fold(false, |acc, x| x > 2 || acc);
  36     let _ = (0..3).fold(true, |acc, x| x > 2 && acc);
  37     let _ = (0..3).fold(0, |acc, x| x + acc);
  38     let _ = (0..3).fold(1, |acc, x| x * acc);
  39
  40     let _ = [(0..2), (0..3)].iter().fold(0, |a, b| a + b.len());
  41     let _ = [(0..2), (0..3)].iter().fold(1, |a, b| a * b.len());
  42 }
  43
  44 /// Should lint only the line containing the fold
  45 fn unnecessary_fold_over_multiple_lines() {
  46     let _ = (0..3)
  47         .map(|x| x + 1)
  48         .filter(|x| x % 2 == 0)
  49         .any(|x| x > 2);
  50 }
  51
  52 fn main() {}