src/tools/clippy/tests/ui/op_ref.rs

#![warn(clippy::op_ref)]
#![expect(clippy::disallowed_names)]
use std::collections::HashSet;
use std::ops::{BitAnd, Mul};

fn main() {
    let tracked_fds: HashSet<i32> = HashSet::new();
    let new_fds = HashSet::new();
    let unwanted = &tracked_fds - &new_fds;

    let foo = &5 - &6;
    //~^ op_ref

    let bar = String::new();
    let bar = "foo" == &bar;

    let a = "a".to_string();
    let b = "a";

    if b < &a {
        println!("OK");
    }

    struct X(i32);
    impl BitAnd for X {
        type Output = X;
        fn bitand(self, rhs: X) -> X {
            X(self.0 & rhs.0)
        }
    }
    impl<'a> BitAnd<&'a X> for X {
        type Output = X;
        fn bitand(self, rhs: &'a X) -> X {
            X(self.0 & rhs.0)
        }
    }
    let x = X(1);
    let y = X(2);
    let z = x & &y;

    #[derive(Copy, Clone)]
    struct Y(i32);
    impl BitAnd for Y {
        type Output = Y;
        fn bitand(self, rhs: Y) -> Y {
            Y(self.0 & rhs.0)
        }
    }
    impl<'a> BitAnd<&'a Y> for Y {
        type Output = Y;
        fn bitand(self, rhs: &'a Y) -> Y {
            Y(self.0 & rhs.0)
        }
    }
    let x = Y(1);
    let y = Y(2);
    let z = x & &y;
    //~^ op_ref
}

#[derive(Clone, Copy)]
struct A(i32);
#[derive(Clone, Copy)]
struct B(i32);

impl Mul<&A> for B {
    type Output = i32;
    fn mul(self, rhs: &A) -> Self::Output {
        self.0 * rhs.0
    }
}
impl Mul<A> for B {
    type Output = i32;
    fn mul(self, rhs: A) -> Self::Output {
        // Should not lint because removing the reference would lead to unconditional recursion
        self * &rhs
    }
}
impl Mul<&A> for A {
    type Output = i32;
    fn mul(self, rhs: &A) -> Self::Output {
        self.0 * rhs.0
    }
}
impl Mul<A> for A {
    type Output = i32;
    fn mul(self, rhs: A) -> Self::Output {
        let one = B(1);
        let two = 2;
        let three = 3;
        let _ = one * &self;
        //~^ op_ref

        let _ = two + &three;
        //~^ op_ref

        // Removing the reference would lead to unconditional recursion
        self * &rhs
    }
}

mod issue_2597 {
    fn ex1() {
        let a: &str = "abc";
        let b: String = "abc".to_owned();
        println!("{}", a > &b);
    }

    pub fn ex2<T: Ord + PartialOrd>(array: &[T], val: &T, idx: usize) -> bool {
        &array[idx] < val
    }
}

#[allow(clippy::needless_ifs)]
fn issue15063() {
    use std::ops::BitAnd;

    macro_rules! mac {
        ($e:expr) => {
            $e.clone()
        };
    }

    let x = 1;
    if &x == &mac!(1) {}
    //~^ op_ref

    #[derive(Copy, Clone)]
    struct Y(i32);
    impl BitAnd for Y {
        type Output = Y;
        fn bitand(self, rhs: Y) -> Y {
            Y(self.0 & rhs.0)
        }
    }
    impl<'a> BitAnd<&'a Y> for Y {
        type Output = Y;
        fn bitand(self, rhs: &'a Y) -> Y {
            Y(self.0 & rhs.0)
        }
    }
    let x = Y(1);
    let y = Y(2);
    let z = x & &mac!(y);
    //~^ op_ref
}