rust/tests/ui/trivially_copy_pass_by_ref.rs

// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#![allow(
    clippy::many_single_char_names,
    clippy::blacklisted_name,
    clippy::redundant_field_names
)]

#[derive(Copy, Clone)]
struct Foo(u32);

#[derive(Copy, Clone)]
struct Bar([u8; 24]);

#[derive(Copy, Clone)]
pub struct Color {
    pub r: u8,
    pub g: u8,
    pub b: u8,
    pub a: u8,
}

struct FooRef<'a> {
    foo: &'a Foo,
}

type Baz = u32;

fn good(a: &mut u32, b: u32, c: &Bar) {}

fn good_return_implicit_lt_ref(foo: &Foo) -> &u32 {
    &foo.0
}

#[allow(clippy::needless_lifetimes)]
fn good_return_explicit_lt_ref<'a>(foo: &'a Foo) -> &'a u32 {
    &foo.0
}

fn good_return_implicit_lt_struct(foo: &Foo) -> FooRef {
    FooRef { foo }
}

#[allow(clippy::needless_lifetimes)]
fn good_return_explicit_lt_struct<'a>(foo: &'a Foo) -> FooRef<'a> {
    FooRef { foo }
}

fn bad(x: &u32, y: &Foo, z: &Baz) {}

impl Foo {
    fn good(self, a: &mut u32, b: u32, c: &Bar) {}

    fn good2(&mut self) {}

    fn bad(&self, x: &u32, y: &Foo, z: &Baz) {}

    fn bad2(x: &u32, y: &Foo, z: &Baz) {}
}

impl AsRef<u32> for Foo {
    fn as_ref(&self) -> &u32 {
        &self.0
    }
}

impl Bar {
    fn good(&self, a: &mut u32, b: u32, c: &Bar) {}

    fn bad2(x: &u32, y: &Foo, z: &Baz) {}
}

trait MyTrait {
    fn trait_method(&self, _foo: &Foo);
}

pub trait MyTrait2 {
    fn trait_method2(&self, _color: &Color);
}

impl MyTrait for Foo {
    fn trait_method(&self, _foo: &Foo) {
        unimplemented!()
    }
}

fn main() {
    let (mut foo, bar) = (Foo(0), Bar([0; 24]));
    let (mut a, b, c, x, y, z) = (0, 0, Bar([0; 24]), 0, Foo(0), 0);
    good(&mut a, b, &c);
    good_return_implicit_lt_ref(&y);
    good_return_explicit_lt_ref(&y);
    bad(&x, &y, &z);
    foo.good(&mut a, b, &c);
    foo.good2();
    foo.bad(&x, &y, &z);
    Foo::bad2(&x, &y, &z);
    bar.good(&mut a, b, &c);
    Bar::bad2(&x, &y, &z);
    foo.as_ref();
}