extern crate rustc_version;
use rustc_version::{Version, version};
fn main() {
let version = version().expect("Failed to get rustc version.");
if version < Version::parse("1.42.0").unwrap() {
eprintln!(
"\n\nAt least Rust version 1.42 is required.\n\
Version {} is used for building.\n\
Build aborted.\n\n",
version);
panic!();
}
}