cc622608db
`must_use_unit` lints unit-returning functions with a `#[must_use]` attribute, suggesting to remove it. `double_must_use` lints functions with a plain `#[must_use]` attribute, but which return a type which is already `#[must_use]`, so the attribute has no benefit. `must_use_candidate` is a pedantic lint that lints functions and methods that return some non-unit type that is not already `#[must_use]` and suggests to add the annotation.
308 lines
7.0 KiB
Rust
308 lines
7.0 KiB
Rust
// aux-build:option_helpers.rs
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// compile-flags: --edition 2018
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#![warn(clippy::all, clippy::pedantic, clippy::option_unwrap_used)]
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#![allow(
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clippy::blacklisted_name,
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clippy::default_trait_access,
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clippy::missing_docs_in_private_items,
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clippy::non_ascii_literal,
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clippy::new_without_default,
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clippy::needless_pass_by_value,
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clippy::print_stdout,
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clippy::must_use_candidate,
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clippy::use_self,
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clippy::useless_format,
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clippy::wrong_self_convention,
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unused
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)]
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#[macro_use]
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extern crate option_helpers;
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use std::collections::BTreeMap;
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use std::collections::HashMap;
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use std::collections::HashSet;
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use std::collections::VecDeque;
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use std::iter::FromIterator;
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use std::ops::Mul;
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use std::rc::{self, Rc};
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use std::sync::{self, Arc};
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use option_helpers::IteratorFalsePositives;
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pub struct T;
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impl T {
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pub fn add(self, other: T) -> T {
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self
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}
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// no error, not public interface
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pub(crate) fn drop(&mut self) {}
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// no error, private function
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fn neg(self) -> Self {
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self
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}
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// no error, private function
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fn eq(&self, other: T) -> bool {
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true
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}
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// No error; self is a ref.
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fn sub(&self, other: T) -> &T {
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self
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}
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// No error; different number of arguments.
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fn div(self) -> T {
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self
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}
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// No error; wrong return type.
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fn rem(self, other: T) {}
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// Fine
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fn into_u32(self) -> u32 {
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0
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}
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fn into_u16(&self) -> u16 {
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0
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}
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fn to_something(self) -> u32 {
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0
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}
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fn new(self) -> Self {
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unimplemented!();
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}
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}
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struct Lt<'a> {
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foo: &'a u32,
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}
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impl<'a> Lt<'a> {
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// The lifetime is different, but that’s irrelevant; see issue #734.
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#[allow(clippy::needless_lifetimes)]
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pub fn new<'b>(s: &'b str) -> Lt<'b> {
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unimplemented!()
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}
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}
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struct Lt2<'a> {
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foo: &'a u32,
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}
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impl<'a> Lt2<'a> {
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// The lifetime is different, but that’s irrelevant; see issue #734.
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pub fn new(s: &str) -> Lt2 {
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unimplemented!()
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}
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}
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struct Lt3<'a> {
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foo: &'a u32,
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}
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impl<'a> Lt3<'a> {
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// The lifetime is different, but that’s irrelevant; see issue #734.
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pub fn new() -> Lt3<'static> {
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unimplemented!()
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}
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}
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#[derive(Clone, Copy)]
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struct U;
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impl U {
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fn new() -> Self {
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U
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}
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// Ok because `U` is `Copy`.
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fn to_something(self) -> u32 {
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0
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}
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}
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struct V<T> {
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_dummy: T,
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}
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impl<T> V<T> {
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fn new() -> Option<V<T>> {
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None
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}
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}
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struct AsyncNew;
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impl AsyncNew {
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async fn new() -> Option<Self> {
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None
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}
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}
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struct BadNew;
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impl BadNew {
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fn new() -> i32 {
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0
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}
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}
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impl Mul<T> for T {
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type Output = T;
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// No error, obviously.
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fn mul(self, other: T) -> T {
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self
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}
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}
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/// Checks implementation of the following lints:
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/// * `OPTION_MAP_UNWRAP_OR`
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/// * `OPTION_MAP_UNWRAP_OR_ELSE`
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#[rustfmt::skip]
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fn option_methods() {
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let opt = Some(1);
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// Check `OPTION_MAP_UNWRAP_OR`.
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// Single line case.
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let _ = opt.map(|x| x + 1)
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// Should lint even though this call is on a separate line.
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.unwrap_or(0);
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// Multi-line cases.
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let _ = opt.map(|x| {
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x + 1
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}
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).unwrap_or(0);
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let _ = opt.map(|x| x + 1)
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.unwrap_or({
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0
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});
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// Single line `map(f).unwrap_or(None)` case.
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let _ = opt.map(|x| Some(x + 1)).unwrap_or(None);
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// Multi-line `map(f).unwrap_or(None)` cases.
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let _ = opt.map(|x| {
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Some(x + 1)
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}
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).unwrap_or(None);
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let _ = opt
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.map(|x| Some(x + 1))
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.unwrap_or(None);
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// macro case
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let _ = opt_map!(opt, |x| x + 1).unwrap_or(0); // should not lint
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// Should not lint if not copyable
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let id: String = "identifier".to_string();
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let _ = Some("prefix").map(|p| format!("{}.{}", p, id)).unwrap_or(id);
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// ...but DO lint if the `unwrap_or` argument is not used in the `map`
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let id: String = "identifier".to_string();
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let _ = Some("prefix").map(|p| format!("{}.", p)).unwrap_or(id);
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// Check OPTION_MAP_UNWRAP_OR_ELSE
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// single line case
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let _ = opt.map(|x| x + 1)
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// Should lint even though this call is on a separate line.
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.unwrap_or_else(|| 0);
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// Multi-line cases.
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let _ = opt.map(|x| {
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x + 1
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}
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).unwrap_or_else(|| 0);
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let _ = opt.map(|x| x + 1)
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.unwrap_or_else(||
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0
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);
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// Macro case.
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// Should not lint.
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let _ = opt_map!(opt, |x| x + 1).unwrap_or_else(|| 0);
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// Issue #4144
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{
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let mut frequencies = HashMap::new();
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let word = "foo";
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frequencies
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.get_mut(word)
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.map(|count| {
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*count += 1;
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})
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.unwrap_or_else(|| {
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frequencies.insert(word.to_owned(), 1);
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});
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}
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}
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/// Checks implementation of `FILTER_NEXT` lint.
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#[rustfmt::skip]
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fn filter_next() {
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let v = vec![3, 2, 1, 0, -1, -2, -3];
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// Single-line case.
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let _ = v.iter().filter(|&x| *x < 0).next();
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// Multi-line case.
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let _ = v.iter().filter(|&x| {
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*x < 0
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}
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).next();
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// Check that hat we don't lint if the caller is not an `Iterator`.
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let foo = IteratorFalsePositives { foo: 0 };
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let _ = foo.filter().next();
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}
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/// Checks implementation of `SEARCH_IS_SOME` lint.
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#[rustfmt::skip]
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fn search_is_some() {
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let v = vec![3, 2, 1, 0, -1, -2, -3];
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let y = &&42;
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// Check `find().is_some()`, single-line case.
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let _ = v.iter().find(|&x| *x < 0).is_some();
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let _ = (0..1).find(|x| **y == *x).is_some(); // one dereference less
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let _ = (0..1).find(|x| *x == 0).is_some();
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let _ = v.iter().find(|x| **x == 0).is_some();
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// Check `find().is_some()`, multi-line case.
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let _ = v.iter().find(|&x| {
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*x < 0
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}
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).is_some();
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// Check `position().is_some()`, single-line case.
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let _ = v.iter().position(|&x| x < 0).is_some();
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// Check `position().is_some()`, multi-line case.
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let _ = v.iter().position(|&x| {
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x < 0
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}
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).is_some();
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// Check `rposition().is_some()`, single-line case.
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let _ = v.iter().rposition(|&x| x < 0).is_some();
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// Check `rposition().is_some()`, multi-line case.
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let _ = v.iter().rposition(|&x| {
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x < 0
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}
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).is_some();
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// Check that we don't lint if the caller is not an `Iterator`.
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let foo = IteratorFalsePositives { foo: 0 };
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let _ = foo.find().is_some();
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let _ = foo.position().is_some();
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let _ = foo.rposition().is_some();
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}
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#[allow(clippy::similar_names)]
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fn main() {
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let opt = Some(0);
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let _ = opt.unwrap();
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}
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