Rust 特征与泛型区别点

use std::boxed::Box;
// 定义一个特征
pub trait Animal{
    fn bark(&self);
}
pub struct Dog{
    pub name: String,
}
pub struct Chicken{
    pub name: String,
}
// 实现一个特征
impl Animal for Dog{
    fn bark(&self){
        println!("{} :  wang wang wang !",&self.name)
    }
}
// 实现特征
impl Animal for Chicken{
    fn bark(&self){
        println!("{} :  ji ji ji ~",&self.name)
    }
}
pub struct Zoo{
    // 用一个list装动物
    pub components: Vec<Box<dyn Animal>>,
}
// 给Zoo实现一个方法
impl Zoo{
    pub fn run(&self){
        for  c in self.components.iter() {
            c.bark();
        } 
    }
}

use animal::{Zoo,Chicken,Dog};
fn main() {
  	// 实例化结构体，并放入了两个对象
    let zoo = Zoo{
        components: vec![ 
            Box::new(Chicken{
                name: String::from("xiao ji"),
            }),
            Box::new(Dog{
                name: String::from("旺财"),
            }),
        ],
    };
    zoo.run();
}

xiao ji is bark
旺财 is bark

pub trait Animal{
    fn bark(&self);
}
pub struct Dog{
    pub name: String,
}
pub struct Chicken{
    pub name: String,
}
impl Animal for Dog{
    fn bark(&self){
        println!("{} is bark",&self.name)
    }
}
impl Animal for Chicken{
    fn bark(&self){
        println!("{} is bark",&self.name)
    }
}
// 把特征换成泛型
pub struct Zoo<T: Animal>{
    pub components: Vec<T>,
}
impl <T> Zoo<T> where T: Animal{
    pub fn run(&self){
        for  c in self.components.iter() {
            c.bark();
        } 
    }
}

160 | pub struct Box<T: ?Sized>(Unique<T>);
    | ------------------------------------- doesn't satisfy `std::boxed::Box<animal::Chicken>: animal::Animal`
    |
    = note: the method `run` exists but the following trait bounds were not satisfied:
            `std::boxed::Box<animal::Chicken>: animal::Animal`