Trait ref_ops::RefSub

pub trait RefSub<Rhs = Self>: Sealed<Rhs> {
    type Output;

    // Required method
    fn ref_sub(&self, rhs: Rhs) -> Self::Output;
}

sub operation through references.

As of Rust 1.73.0, the following code does not compile:

use core::ops::Sub;

struct A<T>(T);

impl<'a, 'b, T, U> Sub<&'b A<U>> for &'a A<T>
where
    &'a T: Sub<&'b U>,
{
    type Output = A<<&'a T as Sub<&'b U>>::Output>;

    fn sub(self, rhs: &'b A<U>) -> Self::Output {
        A(self.0.sub(&rhs.0))
    }
}

fn _f<T, U>(a: T, b: U)
where
    for<'a, 'b> &'a T: Sub<&'b U>,
{
    let _a_op_b = (&a).sub(&b);

    // to do something with `a`, `b`, and `_a_op_b`
}

fn _g<T, U>(a: T, b: U)
where
    for<'a, 'b> &'a T: Sub<&'b U>,
{
    _f(a, b);
}

but the following code does:

use core::ops::Sub;
use ref_ops::RefSub;

struct A<T>(T);

impl<'a, T, U> Sub<&'a A<U>> for &A<T>
where
    T: RefSub<&'a U>,
{
    type Output = A<T::Output>;

    fn sub(self, rhs: &'a A<U>) -> Self::Output {
        A(self.0.ref_sub(&rhs.0))
    }
}

fn _f<T, U>(a: T, b: U)
where
    for<'a, 'b> &'a T: Sub<&'b U>,
{
    let _a_op_b = (&a).sub(&b);

    // to do something with `a`, `b`, and `_a_op_b`
}

fn _g<T, U>(a: T, b: U)
where
    for<'a, 'b> &'a T: Sub<&'b U>,
{
    _f(a, b);
}

Required Associated Types

type Output

The resulting type after applying sub operation.

Required Methods

fn ref_sub(&self, rhs: Rhs) -> Self::Output

Performs sub operation.

Implementors

impl<T, Rhs, O> RefSub<Rhs> for Twhere T: ?Sized, for<'a> &'a T: Sub<Rhs, Output = O>,

type Output = O