Consider the following piece of code:

    fn main() 
    { 
        let a = 32; 
        let b = &a; 
    } 

We have created two variable bindings, with the second one (b) pointing at the address for a. The b variable doesn't contain the value of the a variable, but it points to the position a is held at, from which it can obtain a value (in other words, the value of b is borrowed from a).

In terms of our stack diagram, we have this:

If we have a function call another function, but with a parameter, our stack will look slightly different:

    fn second(i: &i32) 
    { 
        let c = 42; 
        println!("{}", *i); 
    } 
 
    fn main()  
    { 
        let a = 32; 
        let b = &a; 
        second(b); 
    } 
 

The i binding points to address 0 and the b variable points to address 0, and this is the parameter being passed to second.

We can use this stack method to think about memory for a complex situation if you like.