Can 'gen_range' be made public?

[LAC-Tech]

Trying to write a fast arbitrary for a jagged vector, where I don't have to allocate N times.

After seeing how arbitrary is done for vec, it'd be useful to be able to riff on that code:

    fn arbitrary(g: &mut Gen) -> Vec<A> {
        let size = {
            let s = g.size();
            g.gen_range(0..s)
        };
        (0..size).map(|_| A::arbitrary(g)).collect()
    }

[Jason5Lee]

I need this to test math-related algorithms. The default generated value range is too large, for example, the following test will fail due to integer overflow.

#[test]
fn test_sum() {
    fn test_sum(v: Vec<i64>) -> bool {
        let mut expected = 0;
        for i in &v {
            expected += i;
        }
        expected == v.iter().sum::<i64>()
    }

    QuickCheck::new()
        .tests(1000)
        .quickcheck(test_sum as fn(Vec<i64>) -> bool);
}