This code should be correct, because according to [IANA IPv4 Special-Purpose Address Registry](https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml) document, all address in `0.0.0.0/8` are not global reachable. ```rust #![feature(ip)] use std::net::Ipv4Addr; fn main() { let ip = Ipv4Addr::new(0, 0, 0, 1); assert!(!ip.is_global()); } ``` But it panic on assertion failed in latest nightly (2019-01-11) (see [Rust Playground](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=1d680e16d48ef1bb4279f850f34ac0d3))