Question about Rust bracket operator plus ampersand

The following snippet is from the (Brown University ver.) Rust book

fn largest<T>(list: &[T]) -> &T {
    let mut largest = &list[0];

    for item in list {
        if item > largest {
            largest = item;
        }
    }

    largest
}

I have a question about the second line. As I understand it, the bracket operator [] automatically de-references the list, so list[0] is, say, an i32. Cool.

Now I have this i32 and put a & in front so I end up with a reference, namely &i32. But how is this okay? Isn't this a reference to an i32 that's created inside the function? Does the i32 not go out-of-scope at the end of this function?

You are correct that the sub-expression list[0] is of type T. What you're missing is that there are different categories of expressions. Index operators yield a place expression which means it represents an existing memory location instead of a temporary value.

When you use & on a place expression, you get a reference to the existing value and not to a temporary.