In ring, we sometimes need to treat a &[u64] slice as a &[u32] slice and/or a &[u8] slice. We use unsafe to do this, but we would prefer it to be built into libcore or the language instead.
For various reasons we benefit from converting a slice &[u8] to an array reference &[u8; n] after verifying that the slice has n elements, which requires us to use unsafe. This is another thing that we think should be built-in to the language and/or standard library instead.
We keep our hacks for things that should be built-in in one module: