I'm having trouble following an example in "The Stack and the Heap"

help
6

Ok, here's a modified version that reveals the horrifying truth!

macro_rules! show {
    ($ptr:ident) => {
        println!("{} at 0x{:016x} → 0x{:016x}",
            stringify!($ptr),
            (&$ptr) as *const _ as usize,
            (&*$ptr) as *const _ as usize
        );
    };
}

fn bar() {
    let d = Box::new(5);
    show!(d);
    let e = &d;
    show!(e);

    baz(e);
}

fn baz(f: &i32) {
    show!(f);
}

fn main() {
    bar();
}

Output:

d at 0x00007fffb35c10a8 → 0x00007fee14c23010
e at 0x00007fffb35c0fa8 → 0x00007fffb35c10a8
f at 0x00007fffb35c0e50 → 0x00007fee14c23010