1 files changed, 3 insertions, 10 deletions
diff --git a/src/librustc_data_structures/lib.rs b/src/librustc_data_structures/lib.rs
index a46f8aed324..08b453cf493 100644
--- a/src/librustc_data_structures/lib.rs
+++ b/src/librustc_data_structures/lib.rs
@@ -24,23 +24,16 @@
 #![cfg_attr(unix, feature(libc))]
 #![cfg_attr(test, feature(test))]
 
-extern crate core;
-extern crate ena;
+#![deny(rust_2018_idioms)]
+
 #[macro_use]
 extern crate log;
+#[allow(unused_extern_crates)]
 extern crate serialize as rustc_serialize; // used by deriving
 #[cfg(unix)]
 extern crate libc;
-extern crate parking_lot;
 #[macro_use]
 extern crate cfg_if;
-extern crate stable_deref_trait;
-extern crate rustc_rayon as rayon;
-extern crate rustc_rayon_core as rayon_core;
-extern crate rustc_hash;
-extern crate serialize;
-extern crate graphviz;
-extern crate smallvec;
 
 // See librustc_cratesio_shim/Cargo.toml for a comment explaining this.
 #[allow(unused_extern_crates)]