#![feature(unsize, coerce_unsized)]
#![allow(unused)]

use std::ops::CoerceUnsized;
use std::marker::Unsize;
use std::any::Any;

struct Foo<T: ?Sized, U: ?Sized>(Box<T>, Box<U>);

impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Foo<dyn Any, dyn Any>> for Foo<T, U> {}