Today I’ve stumbled on this PR, which suggest that using *const where *mut is expected might be unsound (at least, that’s what relnotes say?)
Is this really unsound though? In my current view of the world, this is not unsound (by itself). What matters is how did you get that pointer. If you originally had an &mut __m256i then using *const or *mut should be OK. If you originally had an &__m256i, then both are unsound.
cc @RalfJung 