Example
fn is_prime(n: u64) -> bool {
(2..n).all(|divisor| n % divisor != 0)
}
Of course this is isn't a fast test. We can stop testing at the square root of n:
(2..n)
.take_while(|divisor| divisor * divisor <= n)
.all(|divisor| n % divisor != 0)
