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use std::cell::Cell;
use std::marker::PhantomPinned;
use std::pin::Pin;
struct MyType<'a>(Cell<Option<&'a mut MyType<'a>>>, PhantomPinned);
impl<'a> Clone for &'a mut MyType<'a> {
//~^ ERROR E0751
fn clone(&self) -> &'a mut MyType<'a> {
self.0.take().unwrap()
}
}
fn main() {
let mut unpinned = MyType(Cell::new(None), PhantomPinned);
let bad_addr = &unpinned as *const MyType<'_> as usize;
let mut p = Box::pin(MyType(Cell::new(Some(&mut unpinned)), PhantomPinned));
// p_mut1 is okay: it does not point to the bad_addr
let p_mut1: Pin<&mut MyType<'_>> = p.as_mut();
assert_ne!(bad_addr, &*p_mut1 as *const _ as usize);
// but p_mut2 does point to bad_addr! this is unsound
let p_mut2: Pin<&mut MyType<'_>> = p_mut1.clone();
assert_eq!(bad_addr, &*p_mut2 as *const _ as usize);
}
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