Rust 即使关联类型不同，特征实现也存在冲突

我试图创建一个通用 struct ，它封装了isize或AtomicIsize，但当我试图为 struct 的两种可能实现实现实现一个trait时，我遇到了一个错误.我在下面创建了一个简单的例子来说明我的问题.

use std::sync::atomic::{AtomicIsize, Ordering};
use std::ops::Deref;
use std::marker::PhantomData;

pub trait Counted {
    fn inc(&self, value: isize);
}

pub type PlainCounter = isize;
pub type AtomicCounter = AtomicIsize;


pub struct Counter<'a, T: 'a> {
    counter: T,
    phantom: PhantomData<&'a T>,
}

impl<'a, T> Counter<'a, T>
    where T: Deref<Target = PlainCounter>
{
    pub fn new(counter: T) -> Self {
        Counter {
            counter: counter,
            phantom: PhantomData,
        }
    }
}

impl<'a, T> Counted for Counter<'a, T>
    where T: Deref<Target = PlainCounter>
{
    fn inc(&self, value: isize) {
        self.counter += 1;
    }
}

impl<'a, T> Counter<'a, T>
    where T: Deref<Target = AtomicCounter>
{
    pub fn new(counter: T) -> Self {
        Counter {
            counter: counter,
            phantom: PhantomData,
        }
    }
}

impl<'a, T> Counted for Counter<'a, T>
    where T: Deref<Target = AtomicCounter>
{
    fn inc(&self, value: isize) {
        self.counter.fetch_add(value, Ordering::SeqCst);
    }
}

(playground)

我得到的错误是编译器找到了conflicting implementations of trait `Counted` for type `Counter<'_, _>`.编译器似乎无法确定实现是针对两种不同的类型T，即T: Deref<Target = PlainCounter>和T: Deref<Target = AtomicCounter>.是否有一种方法可以向编译器提供额外的信息，以便它能够区分这两种情况，还是我完全走错了路？