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Document the current aliasing rules for Box<T>. #97229

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merged 2 commits into from
May 31, 2022
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Document the current aliasing rules for Box<T>. #97229

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e7c468d
Document the current aliasing rules for `Box<T>`.
Noratrieb May 20, 2022
ffd7f58
Fix typo uniqeness -> uniqueness
dtolnay May 30, 2022
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14 changes: 14 additions & 0 deletions library/alloc/src/boxed.rs
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Expand Up @@ -122,7 +122,21 @@
//! definition is just using `T*` can lead to undefined behavior, as
//! described in [rust-lang/unsafe-code-guidelines#198][ucg#198].
//!
//! # Considerations for unsafe code
//!
//! **Warning: This section is not normative and is subject to change, possibly
//! being relaxed in the future! It is a simplified summary of the rules
//! currently implemented in the compiler.**
//!
//! The aliasing rules for `Box<T>` are the same as for `&mut T`. `Box<T>`
//! asserts uniqueness over its content. Using raw pointers derived from a box
//! after that box has been mutated through, moved or borrowed as `&mut T`
//! is not allowed. For more guidance on working with box from unsafe code, see
//! [rust-lang/unsafe-code-guidelines#326][ucg#326].
//!
//!
//! [ucg#198]: https://github.com/rust-lang/unsafe-code-guidelines/issues/198
//! [ucg#326]: https://github.com/rust-lang/unsafe-code-guidelines/issues/326
//! [dereferencing]: core::ops::Deref
//! [`Box::<T>::from_raw(value)`]: Box::from_raw
//! [`Global`]: crate::alloc::Global
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