override_mul_operator.rs

use std::ops::Mul;

#[derive(Debug)]
struct Vector {
    x : f64,
    y : f64
}

impl<'a> Mul<f64> for &'a Vector {
    type Output = Vector;

    fn mul(self, k : f64) -> Vector {
        Vector { x: self.x * k, y: self.y * k }
    }
}

impl<'a> Mul<i32> for &'a Vector {
    type Output = Vector;

    fn mul(self, k : i32) -> Vector {
        let k = k as f64;
        Vector { x: self.x * k, y: self.y * k }
    }
}

fn main() {
    let v = Vector { x: 1.0, y: 2.0 };
    let v2 = &v * 1.5;
    let v3 = &v * 3;

    println!("{:?}", v2);
    println!("{:?}", v3);
}

use std::ops::Mul;

#[derive(Debug)]
#[derive(Clone)]
#[derive(Copy)]
struct Vector {
    x : f64,
    y : f64
}

impl Mul<f64> for Vector {
    type Output = Vector;

    fn mul(self, k: f64) -> Self::Output {
        Vector { x: self.x * k, y: self.y * k }
    }
}

impl Mul<i32> for Vector {
    type Output = Vector;

    fn mul(self, k: i32) -> Self::Output {
        return self * k as f64;
    }
}

fn main() {
    let v = Vector { x: 1.0, y: 2.0 };
    let v2 = v * 1.5;
    let v3 = v * 3;

    println!("{:?}", v2);
    println!("{:?}", v3);
}

If you don't mind of copy things a bit.