Shared via Rust Playground

playground.rs

use std::slice;

type Iter<'a> = Iterator<Item=&'a i32>;

struct Struct<'a> { _phantom: std::marker::PhantomData<&'a i32> }

impl<'a> Struct<'a> {
    fn direct<'b>(i: &'b slice::Iter<'a, i32>) -> &'b Iterator<Item=&'a i32>
    { i }
    
    fn aliased<'b>(i: &'b slice::Iter<'a, i32>) -> &'b Iter<'a>
    { i }
}

fn main() {
}