mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-09-20 14:41:58 +00:00
74 lines
2.6 KiB
Rust
74 lines
2.6 KiB
Rust
#![allow(dead_code)]
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/// Calls which should trigger the `UNNECESSARY_FOLD` lint
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fn unnecessary_fold() {
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// Can be replaced by .any
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let _ = (0..3).fold(false, |acc, x| acc || x > 2);
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// Can be replaced by .all
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let _ = (0..3).fold(true, |acc, x| acc && x > 2);
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// Can be replaced by .sum
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let _: i32 = (0..3).fold(0, |acc, x| acc + x);
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// Can be replaced by .product
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let _: i32 = (0..3).fold(1, |acc, x| acc * x);
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}
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/// Should trigger the `UNNECESSARY_FOLD` lint, with an error span including exactly `.fold(...)`
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fn unnecessary_fold_span_for_multi_element_chain() {
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let _: bool = (0..3).map(|x| 2 * x).fold(false, |acc, x| acc || x > 2);
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}
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/// Calls which should not trigger the `UNNECESSARY_FOLD` lint
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fn unnecessary_fold_should_ignore() {
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let _ = (0..3).fold(true, |acc, x| acc || x > 2);
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let _ = (0..3).fold(false, |acc, x| acc && x > 2);
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let _ = (0..3).fold(1, |acc, x| acc + x);
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let _ = (0..3).fold(0, |acc, x| acc * x);
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let _ = (0..3).fold(0, |acc, x| 1 + acc + x);
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// We only match against an accumulator on the left
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// hand side. We could lint for .sum and .product when
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// it's on the right, but don't for now (and this wouldn't
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// be valid if we extended the lint to cover arbitrary numeric
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// types).
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let _ = (0..3).fold(false, |acc, x| x > 2 || acc);
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let _ = (0..3).fold(true, |acc, x| x > 2 && acc);
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let _ = (0..3).fold(0, |acc, x| x + acc);
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let _ = (0..3).fold(1, |acc, x| x * acc);
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let _ = [(0..2), (0..3)].iter().fold(0, |a, b| a + b.len());
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let _ = [(0..2), (0..3)].iter().fold(1, |a, b| a * b.len());
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}
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/// Should lint only the line containing the fold
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fn unnecessary_fold_over_multiple_lines() {
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let _ = (0..3)
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.map(|x| x + 1)
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.filter(|x| x % 2 == 0)
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.fold(false, |acc, x| acc || x > 2);
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}
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fn issue10000() {
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use std::collections::HashMap;
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use std::hash::BuildHasher;
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fn anything<T>(_: T) {}
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fn num(_: i32) {}
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fn smoketest_map<S: BuildHasher>(mut map: HashMap<i32, i32, S>) {
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map.insert(0, 0);
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assert_eq!(map.values().fold(0, |x, y| x + y), 0);
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// more cases:
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let _ = map.values().fold(0, |x, y| x + y);
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let _ = map.values().fold(1, |x, y| x * y);
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let _: i32 = map.values().fold(0, |x, y| x + y);
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let _: i32 = map.values().fold(1, |x, y| x * y);
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anything(map.values().fold(0, |x, y| x + y));
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anything(map.values().fold(1, |x, y| x * y));
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num(map.values().fold(0, |x, y| x + y));
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num(map.values().fold(1, |x, y| x * y));
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}
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smoketest_map(HashMap::new());
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}
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fn main() {}
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