use std::cell::Cell;

#[derive(Default)]
struct A(Cell<i32>);

impl PartialEq<i32> for A {
    fn eq(&self, i: &i32) -> bool {
        self.0.set(self.0.get() + 1);
        self.0.get() == *i
    }
}

fn main() {
    let a = A::default();

    if a == 1 && a == 2 && a == 3 {
        println!("gotcha!")
    }
}