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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/traits/negative-impls/pin-unsound-issue-66544-derefmut.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/test/ui/traits/negative-impls/pin-unsound-issue-66544-derefmut.rs | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/src/test/ui/traits/negative-impls/pin-unsound-issue-66544-derefmut.rs b/src/test/ui/traits/negative-impls/pin-unsound-issue-66544-derefmut.rs new file mode 100644 index 000000000..606cc65a8 --- /dev/null +++ b/src/test/ui/traits/negative-impls/pin-unsound-issue-66544-derefmut.rs @@ -0,0 +1,33 @@ +// Demonstrate that "rogue" `DerefMut` impls for `&T` are not allowed. +// +// https://github.com/rust-lang/rust/issues/66544 + +use std::cell::Cell; +use std::marker::PhantomPinned; +use std::ops::DerefMut; +use std::pin::Pin; + +struct MyType<'a>(Cell<Option<&'a mut MyType<'a>>>, PhantomPinned); + +impl<'a> DerefMut for &'a MyType<'a> { + //~^ ERROR E0751 + fn deref_mut(&mut self) -> &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 p = Box::pin(MyType(Cell::new(Some(&mut unpinned)), PhantomPinned)); + + // p_ref is okay: it does not point to the bad_addr + let mut p_ref: Pin<&MyType<'_>> = p.as_ref(); + assert_ne!(bad_addr, &*p_ref as *const _ as usize); + + // but p_mut does point to bad_addr! this is unsound + let p_mut: Pin<&mut MyType<'_>> = p_ref.as_mut(); + assert_eq!(bad_addr, &*p_mut as *const _ as usize); + + println!("oh no!"); +} |