Note that NonNull does not launder shared references for mutation
This commit is contained in:
parent
7486b9c208
commit
7fcdb93cf5
1 changed files with 9 additions and 0 deletions
|
@ -2874,6 +2874,15 @@ impl<'a, T: ?Sized> From<NonNull<T>> for Unique<T> {
|
|||
/// Usually this won't be necessary; covariance is correct for most safe abstractions,
|
||||
/// such as Box, Rc, Arc, Vec, and LinkedList. This is the case because they
|
||||
/// provide a public API that follows the normal shared XOR mutable rules of Rust.
|
||||
///
|
||||
/// Notice that `NonNull<T>` has a `From` instance for `&T`. However, this does
|
||||
/// not change the fact that mutating through a (pointer derived from a) shared
|
||||
/// reference is undefined behavior unless the mutation happens inside an
|
||||
/// [`UnsafeCell<T>`]. When using this `From` instance without an `UnsafeCell<T>`,
|
||||
/// it is your responsibility to ensure that `as_mut` is never called, and `as_ptr`
|
||||
/// is never used for mutation.
|
||||
///
|
||||
/// [`UnsafeCell<T>`]: ../cell/struct.UnsafeCell.html
|
||||
#[stable(feature = "nonnull", since = "1.25.0")]
|
||||
#[repr(transparent)]
|
||||
#[rustc_layout_scalar_valid_range_start(1)]
|
||||
|
|
Loading…
Reference in a new issue