Restrict MaybeUninit trait impls to fix soundness #309
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Previously, we implemented `FromZeroes` and `FromBytes` for `MaybeUninit<T>` with no bound on `T`. This resulted in a soundness hole in which `T` - and thus `MaybeUninit<T>` - could contain an `UnsafeCell`, which is a violation of the contracts of `FromZeroes` and `FromBytes`. This is a breaking change, but it's very unlikely to be one that code is currently relying on. In this commit, we publish 0.6.4, and we will yank all preceding 0.6.x versions as soon as 0.6.4 is published. This is a backport of #308
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Previously, we implemented
FromZeroesandFromBytesforMaybeUninit<T>with no bound onT. This resulted in a soundness hole in whichT- and thusMaybeUninit<T>- could contain anUnsafeCell, which is a violation of the contracts ofFromZeroesandFromBytes.This is a breaking change, but it's very unlikely to be one that code is currently relying on. In this commit, we publish 0.6.4, and we will yank all preceding 0.6.x versions as soon as 0.6.4 is published.
This is a backport of #308