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SubjectRe: [PATCH v2 1/4] rust: sync: reword the `Arc` safety comment for `Send`
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On 5/23/23 11:44, Alice Ryhl wrote:
> The safety comment on `impl Send for Arc` talks about "directly"
> accessing the value, when it really means "accessing the value with a
> mutable reference". This commit clarifies that.
>
> Suggested-by: Boqun Feng <boqun.feng@gmail.com>
> Signed-off-by: Alice Ryhl <aliceryhl@google.com>
> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
> Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
> ---
> [...]
>
> // SAFETY: It is safe to send `Arc<T>` to another thread when the underlying `T` is `Sync` because
> // it effectively means sharing `&T` (which is safe because `T` is `Sync`); additionally, it needs
> -// `T` to be `Send` because any thread that has an `Arc<T>` may ultimately access `T` directly, for
> -// example, when the reference count reaches zero and `T` is dropped.
> +// `T` to be `Send` because any thread that has an `Arc<T>` may ultimately access `T` using a
> +// mutable reference, for example, when the reference count reaches zero and `T` is dropped.
> unsafe impl<T: ?Sized + Sync + Send> Send for Arc<T> {}
>
> // SAFETY: It is safe to send `&Arc<T>` to another thread when the underlying `T` is `Sync` for the

Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>

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