//! Set a nightly feature extern crate rustc_version; use rustc_version::{version, version_meta, Channel}; fn main() { // Assert we haven't travelled back in time assert!(version().unwrap().major >= 1); // Set cfg flags depending on release channel if let Channel::Nightly = version_meta().unwrap().channel { println!("cargo:rustc-cfg=feature=\"nightly\""); } }