Implement a trait when another is already implemented

foo.rs

#![allow(dead_code)]

use std::io::{self, Read};
use std::marker::PhantomData;

pub trait Foo<T: Read> {
    fn get_mut(&self) -> &mut T;
}

struct FooStruct<T,R> where T:Read, R:Foo<T> {
    foo : R,
    phantom: PhantomData<T>
}

impl<T,R> Read for FooStruct<T,R> where T:Read, R: Foo<T> {
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
        self.foo.get_mut().read(buf)
    }
}