Exploring unsafe in rust

unsafe_test.rs

extern crate rayon;

use rayon::prelude::*;
use std::marker::PhantomData;
use std::mem;

struct Storage<'a, T : 'a>
{
    ptr: *mut T,
    phantom: PhantomData<&'a T>,
}

impl<'a, T> Storage<'a, T>
{
    fn from(ptr: &mut T) -> Storage<'a, T>
    {
        Storage {
            ptr: unsafe {mem::transmute(ptr)},
            phantom: PhantomData,
        }
    }

    fn clone(&self) -> &'a mut T
    {
        return unsafe { mem::transmute(self.ptr) };
    }
}

unsafe impl<'a, T> Send for Storage<'a, T> {}
unsafe impl<'a, T> Sync for Storage<'a, T> {}



fn main() {

    let mut v : Vec<u8> = vec![1, 2, 3, 4, 5, 6];

    let storage = Storage::from(&mut v);

    (0..6u8).into_par_iter().for_each(move |x|
    {
        let k = storage.clone();
        k[x as usize] = 42 - x;
    });

    // [42, 41, 40, 39, 38, 37]
    println!("{:?}", v)
}