rust 如何实现闭包 Vec？

修改了一下终于可行了，代码：
type Boo = Box<dyn Fn(i32) -> String>;

fn op1(x:i32, y:String) -> impl Fn(i32) -> String {
move |s:i32| {
let mut a = String::new();
a.push_str((x+s).to_string().as_str());
a.push_str(y.as_str());
a
}
}

fn op2(x:i32) -> impl Fn(i32) -> String{
move |s:i32| {
let mut a = String::new();
a.push_str((x+s).to_string().as_str());
a
}
}

fn op3(y:String) ->impl Fn(i32) -> String{
move |s:i32| {
let mut a = String::new();
a.push_str((s).to_string().as_str());
a.push_str(y.as_str());
a
}
}

pub fn c_t5(){
let c1 = Box::new(op1(10,String::from("ab")));
let c2 = Box::new(op2(20));
let c3 = Box::new(op3(String::from("cd")));
let mut vec:Vec<Boo> = Vec::new();
vec.push(c1);
vec.push(c2);
vec.push(c3);
println!("{} {} {}",vec.get(0).unwrap()(30),vec.get(1).unwrap()(30),
vec.get(2).unwrap()(30));//40ab 50 30cd
}