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