// error-pattern:cargo-clippy
#![feature(plugin_registrar)]
-#![feature(rust_2018_preview)]
#![feature(rustc_private)]
-#![feature(macro_vis_matcher)]
-#![allow(unknown_lints)]
-#![allow(missing_docs_in_private_items)]
#![warn(rust_2018_idioms)]
-use rustc_plugin::Registry;
+// FIXME: switch to something more ergonomic here, once available.
+// (Currently there is no way to opt into sysroot crates without `extern crate`.)
+#[allow(unused_extern_crates)]
+extern crate rustc_driver;
+#[allow(unused_extern_crates)]
+extern crate rustc_plugin;
+use self::rustc_plugin::Registry;
#[plugin_registrar]
pub fn plugin_registrar(reg: &mut Registry<'_>) {