| @@ -940,15 +940,18 @@ impl<T, A: Allocator> Arc<T, A> { |
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/// This will succeed even if there are outstanding weak references. |
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/// |
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/// It is strongly recommended to use [`Arc::into_inner`] instead if you don't |
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- /// want to keep the `Arc` in the [`Err`] case. |
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- /// Immediately dropping the [`Err`] payload, like in the expression |
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- /// `Arc::try_unwrap(this).ok()`, can still cause the strong count to |
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- /// drop to zero and the inner value of the `Arc` to be dropped: |
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- /// For instance if two threads each execute this expression in parallel, then |
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- /// there is a race condition. The threads could first both check whether they |
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- /// have the last clone of their `Arc` via `Arc::try_unwrap`, and then |
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- /// both drop their `Arc` in the call to [`ok`][`Result::ok`], |
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- /// taking the strong count from two down to zero. |
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+ /// keep the `Arc` in the [`Err`] case. |
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+ /// Immediately dropping the [`Err`]-value, as the expression |
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+ /// `Arc::try_unwrap(this).ok()` does, can cause the strong count to |
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+ /// drop to zero and the inner value of the `Arc` to be dropped. |
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+ /// For instance, if two threads execute such an expression in parallel, |
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+ /// there is a race condition without the possibility of unsafety: |
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+ /// The threads could first both check whether they own the last instance |
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+ /// in `Arc::try_unwrap`, determine that they both do not, and then both |
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+ /// discard and drop their instance in the call to [`ok`][`Result::ok`]. |
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+ /// In this scenario, the value inside the `Arc` is safely destroyed |
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+ /// by exactly one of the threads, but neither thread will ever be able |
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+ /// to use the value. |
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/// |
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/// # Examples |
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/// |