下面的代码运行时可能出错，或者能运行打印出：

origin before assignment "aa"
origin after assignment "lP"
cloned "bb"

可以看到变量 origin 指针指向的内容在执行 *(cloned.ptr) = "bb".to_string(); 之后发生了改变，但是为什么会这样呢？

use std::ptr::{self};

use std::{
    alloc::{alloc, Layout},
    fmt::{Debug, Display},
};

#[derive(PartialEq)]
pub struct ManualBox2<T> {
    ptr: *mut T,
    layout: Layout,
}
impl<T> ManualBox2<T> {
    pub fn new(value: T) -> Self {
        let layout = Layout::new::<T>();
        let ptr = unsafe { alloc(layout) as *mut T };
        unsafe { ptr.write(value) };
        Self { ptr, layout }
    }
}
impl<T: Display> Display for ManualBox2<T> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", unsafe { &(*self.ptr) })
    }
}
impl<T: Debug> Debug for ManualBox2<T> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{:?}", unsafe { &(*self.ptr) })
    }
}
impl<T> Clone for ManualBox2<T> {
    fn clone(&self) -> Self {
        let layout = self.layout;
        let new_prt = unsafe { alloc(layout) as *mut T };
        unsafe {
            ptr::copy_nonoverlapping(self.ptr, new_prt, 1);
        }
        Self {
            ptr: new_prt,
            layout,
        }
    }
}
fn main() {
    let origin = ManualBox2::new("aa".to_string());
    let cloned = origin.clone();
    println!("origin before assignment {:?}", origin);

    unsafe {
       

        *(cloned.ptr) = "bb".to_string();
    }

    println!("origin after assignment {:?}", origin);

    println!("cloned {:?}", cloned);
}

代码地址