fn f1() -> bool { true }
fn f2() -> bool { false }

fn main() {
    let mut v1 = 42;
    let mut v2 = 666;

    let p1 = if f1() { &v1 } else { &v2 };

    if f2() {
        let p2 = &mut v1;
        *p2 = 37;
        println!("p2: {}", *p2);
    }

    println!("p1: {}", *p1);
}