rust/clippy_tests/examples/map_clone.rs

106 lines
1.9 KiB
Rust

#![feature(plugin)]
#![plugin(clippy)]
#![warn(map_clone)]
#![allow(clone_on_copy, unused)]
use std::ops::Deref;
fn map_clone_iter() {
let x = [1,2,3];
x.iter().map(|y| y.clone());
x.iter().map(|&y| y);
x.iter().map(|y| *y);
x.iter().map(|y| { y.clone() });
x.iter().map(|&y| { y });
x.iter().map(|y| { *y });
x.iter().map(Clone::clone);
}
fn map_clone_option() {
let x = Some(4);
x.as_ref().map(|y| y.clone());
x.as_ref().map(|&y| y);
x.as_ref().map(|y| *y);
}
fn not_linted_option() {
let x = Some(5);
// Not linted: other statements
x.as_ref().map(|y| {
println!("y: {}", y);
y.clone()
});
// Not linted: argument bindings
let x = Some((6, 7));
x.map(|(y, _)| y.clone());
// Not linted: cloning something else
x.map(|y| y.0.clone());
// Not linted: no dereferences
x.map(|y| y);
// Not linted: multiple dereferences
let _: Option<(i32, i32)> = x.as_ref().as_ref().map(|&&x| x);
}
#[derive(Copy, Clone)]
struct Wrapper<T>(T);
impl<T> Wrapper<T> {
fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Wrapper<U> {
Wrapper(f(self.0))
}
}
fn map_clone_other() {
let eight = 8;
let x = Wrapper(&eight);
// Not linted: not a linted type
x.map(|y| y.clone());
x.map(|&y| y);
x.map(|y| *y);
}
#[derive(Copy, Clone)]
struct UnusualDeref;
static NINE: i32 = 9;
impl Deref for UnusualDeref {
type Target = i32;
fn deref(&self) -> &i32 { &NINE }
}
fn map_clone_deref() {
let x = Some(UnusualDeref);
let _: Option<UnusualDeref> = x.as_ref().map(|y| *y);
// Not linted: using deref conversion
let _: Option<i32> = x.map(|y| *y);
// Not linted: using regular deref but also deref conversion
let _: Option<i32> = x.as_ref().map(|y| **y);
}
// stuff that used to be a false positive
fn former_false_positive() {
vec![1].iter_mut().map(|x| *x); // #443
}
fn main() { }