compute prime numbers in Rust

primes.rs

struct Primes {
    primes : Vec<u64>,
}
impl Primes {
    fn new() -> Primes {
        Primes{primes: vec![2]}
    }
    
    fn test(&self, totest: u64) -> bool {
        let mut n = totest;
        for i in &self.primes {
            while n%(*i) == 0 {
                n /= *i;
            }
            if n==1 {return false;}
        }
        return true;
    }
}

impl Iterator for Primes {
    type Item = u64;

    fn next(&mut self) -> Option<u64> {
        let mut n = *self.primes.last().unwrap() + 1;
        while !self.test(n) { n += 1; }
        self.primes.push(n);
        return Some(n);
    }
}

fn main() {
    for i in Primes::new() {println!("{}", i);}
}