Apply #66379 to *mut T as_ref

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aticu 2020-07-20 20:39:17 +02:00
parent f9a3086363
commit 40df8fd0fa

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@ -47,17 +47,22 @@ pub const fn cast<U>(self) -> *mut U {
/// operation because the returned value could be pointing to invalid /// operation because the returned value could be pointing to invalid
/// memory. /// memory.
/// ///
/// When calling this method, you have to ensure that if the pointer is /// When calling this method, you have to ensure that *either* the pointer is NULL *or*
/// non-NULL, then it is properly aligned, dereferenceable (for the whole /// all of the following is true:
/// size of `T`) and points to an initialized instance of `T`. This applies /// - it is properly aligned
/// even if the result of this method is unused! /// - it must point to an initialized instance of T; in particular, the pointer must be
/// "dereferencable" in the sense defined [here].
///
/// This applies even if the result of this method is unused!
/// (The part about being initialized is not yet fully decided, but until /// (The part about being initialized is not yet fully decided, but until
/// it is, the only safe approach is to ensure that they are indeed initialized.) /// it is, the only safe approach is to ensure that they are indeed initialized.)
/// ///
/// Additionally, the lifetime `'a` returned is arbitrarily chosen and does /// Additionally, the lifetime `'a` returned is arbitrarily chosen and does
/// not necessarily reflect the actual lifetime of the data. It is up to the /// not necessarily reflect the actual lifetime of the data. *You* must enforce
/// caller to ensure that for the duration of this lifetime, the memory this /// Rust's aliasing rules. In particular, for the duration of this lifetime,
/// pointer points to does not get written to outside of `UnsafeCell<U>`. /// the memory the pointer points to must not get mutated (except inside `UnsafeCell`).
///
/// [here]: crate::ptr#safety
/// ///
/// # Examples /// # Examples
/// ///