#![allow(dead_code, deprecated, unused_variables, unused_mut)]
#![feature(slice_range)]
use std::slice;
fn main() {
    let v = [10, 40, 30];
    assert_eq!(Some(1..2), slice::try_range(1..2, ..v.len()));
    assert_eq!(Some(0..2), slice::try_range(..2, ..v.len()));
    assert_eq!(Some(1..3), slice::try_range(1.., ..v.len()));
}