#![allow(dead_code, deprecated, unused_variables, unused_mut)]
#![feature(dispatch_from_dyn, unsize)]
use std::{ops::DispatchFromDyn, marker::Unsize};
struct Rc<T: ?Sized>(std::rc::Rc<T>);
impl<T: ?Sized, U: ?Sized> DispatchFromDyn<Rc<U>> for Rc<T>
where
    T: Unsize<U>,
{}
fn main() {}