rust/tests/ui/needless_borrow.rs
2018-10-06 09:43:08 -07:00

65 lines
1.7 KiB
Rust

// 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.
#![feature(tool_lints)]
use std::borrow::Cow;
#[allow(clippy::trivially_copy_pass_by_ref)]
fn x(y: &i32) -> i32 {
*y
}
#[warn(clippy::all, clippy::needless_borrow)]
#[allow(unused_variables)]
fn main() {
let a = 5;
let b = x(&a);
let c = x(&&a);
let s = &String::from("hi");
let s_ident = f(&s); // should not error, because `&String` implements Copy, but `String` does not
let g_val = g(&Vec::new()); // should not error, because `&Vec<T>` derefs to `&[T]`
let vec = Vec::new();
let vec_val = g(&vec); // should not error, because `&Vec<T>` derefs to `&[T]`
h(&"foo"); // should not error, because the `&&str` is required, due to `&Trait`
if let Some(ref cake) = Some(&5) {}
let garbl = match 42 {
44 => &a,
45 => {
println!("foo");
&&a // FIXME: this should lint, too
},
46 => &&a,
_ => panic!(),
};
}
fn f<T:Copy>(y: &T) -> T {
*y
}
fn g(y: &[u8]) -> u8 {
y[0]
}
trait Trait {}
impl<'a> Trait for &'a str {}
fn h(_: &Trait) {}
#[warn(clippy::needless_borrow)]
#[allow(dead_code)]
fn issue_1432() {
let mut v = Vec::<String>::new();
let _ = v.iter_mut().filter(|&ref a| a.is_empty());
let _ = v.iter().filter(|&ref a| a.is_empty());
let _ = v.iter().filter(|&a| a.is_empty());
}