-#![warn(default_hash_types)]
+// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![warn(clippy::default_hash_types)]
#![feature(rustc_private)]
extern crate rustc_data_structures;
-use std::collections::{HashMap, HashSet};
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use std::collections::{HashMap, HashSet};
fn main() {
let _map: HashMap<String, String> = HashMap::default();