Lifetimes Rust

lifetimes.rs

fn main() {

let x1 = vec![1_u8];
let r1 = &x1[..]; // 'l1

let ret = {
  let x2 = vec![2_u8];  
  let r2 = &x2[..]; // 'l2
  let mut y2 = Holder(r2);// Holder<'l2>
  swap(&mut y2, r1);      // Holder<'l2>


  y2 = Holder(r1);           // Holder<'l1>
  y2
};
drop(ret);
}


type Slice<T> = [T]; // DST
type RefSlice<'a,T> = &'a Slice<T>;
type Array<T, const Len : usize> = [T; Len];



struct Holder<'a>(&'a [u8]);

fn swap<'a:'c, 'b:'a, 'c>(h: &mut Holder<'a>, k:&'b [u8])->&'c[u8] {
  let tmp = h.0;
  h.0=k;
  tmp
}