80 lines
2.6 KiB
Rust
80 lines
2.6 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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use std::iter::repeat;
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#[allow(clippy::trivially_copy_pass_by_ref)]
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fn square_is_lower_64(x: &u32) -> bool {
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x * x < 64
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}
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#[allow(clippy::maybe_infinite_iter)]
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#[deny(clippy::infinite_iter)]
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fn infinite_iters() {
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repeat(0_u8).collect::<Vec<_>>(); // infinite iter
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(0..8_u32).take_while(square_is_lower_64).cycle().count(); // infinite iter
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(0..8_u64).chain(0..).max(); // infinite iter
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(0_usize..)
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.chain([0usize, 1, 2].iter().cloned())
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.skip_while(|x| *x != 42)
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.min(); // infinite iter
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(0..8_u32)
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.rev()
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.cycle()
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.map(|x| x + 1_u32)
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.for_each(|x| println!("{}", x)); // infinite iter
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(0..3_u32).flat_map(|x| x..).sum::<u32>(); // infinite iter
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(0_usize..).flat_map(|x| 0..x).product::<usize>(); // infinite iter
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(0_u64..).filter(|x| x % 2 == 0).last(); // infinite iter
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(0..42_u64).by_ref().last(); // not an infinite, because ranges are double-ended
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(0..).next(); // iterator is not exhausted
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}
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#[deny(clippy::maybe_infinite_iter)]
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fn potential_infinite_iters() {
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(0..).zip((0..).take_while(square_is_lower_64)).count(); // maybe infinite iter
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repeat(42).take_while(|x| *x == 42).chain(0..42).max(); // maybe infinite iter
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(1..)
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.scan(0, |state, x| {
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*state += x;
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Some(*state)
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})
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.min(); // maybe infinite iter
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(0..).find(|x| *x == 24); // maybe infinite iter
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(0..).position(|x| x == 24); // maybe infinite iter
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(0..).any(|x| x == 24); // maybe infinite iter
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(0..).all(|x| x == 24); // maybe infinite iter
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(0..).zip(0..42).take_while(|&(x, _)| x != 42).count(); // not infinite
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repeat(42).take_while(|x| *x == 42).next(); // iterator is not exhausted
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}
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fn main() {
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infinite_iters();
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potential_infinite_iters();
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}
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mod finite_collect {
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use std::collections::HashSet;
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use std::iter::FromIterator;
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struct C;
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impl FromIterator<i32> for C {
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fn from_iter<I: IntoIterator<Item = i32>>(iter: I) -> Self {
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C
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}
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}
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fn check_collect() {
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let _: HashSet<i32> = (0..).collect(); // Infinite iter
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// Some data structures don't collect infinitely, such as `ArrayVec`
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let _: C = (0..).collect();
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}
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}
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