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50 lines
2.0 KiB
Rust
50 lines
2.0 KiB
Rust
// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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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 _ = (0..3).fold(0, |acc, x| acc + x);
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// Can be replaced by .product
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let _ = (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 _ = (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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fn main() {}
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