Fix aliasing in Clone by using a raw pointer #523
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Previously, this code produced a &mut[u8] and a Box<[u8]> to the shared allocation upon cloning it. If the underlying allocation were actually shared, such as through a &[u8] from the Deref impl, creating either of these types incorrectly asserted uniqueness of the allocation. This fixes the example in tokio-rs#522, but Miri still does not pass on this test suite with -Zmiri-tag-raw-pointers because Miri does not currently understand int to pointer casts.
Darksonn
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Apr 6, 2022
lelongg
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Jan 9, 2023
Previously, this code produced a &mut[u8] and a Box<[u8]> to the shared allocation upon cloning it. If the underlying allocation were actually shared, such as through a &[u8] from the Deref impl, creating either of these types incorrectly asserted uniqueness of the allocation. This fixes the example in tokio-rs#522, but Miri still does not pass on this test suite with -Zmiri-tag-raw-pointers because Miri does not currently understand int to pointer casts.
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Fixes #522
I feel like it would be good to add a test case to make sure such a thing doesn't come back, but I'm not sure how to do that. There's no way to usefully test this situation without running the code under Miri, but this project doesn't fully work with Miri anyway, because Miri doesn't understand int to pointer casts.