Deny internal lints on librustc_interface

Author: flip1995

src/librustc_interface/interface.rs

@@ -12,7 +12,6 @@ use rustc_data_structures::OnDrop;
 use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::fx::{FxHashSet, FxHashMap};
 use rustc_metadata::cstore::CStore;
-use std::collections::HashSet;
 use std::io::Write;
 use std::path::PathBuf;
 use std::result;

src/librustc_interface/lib.rs

@@ -7,6 +7,7 @@
 #![cfg_attr(unix, feature(libc))]
 
 #![deny(rust_2018_idioms)]
+#![cfg_attr(not(stage0), deny(internal))]
 
 #![allow(unused_imports)]
 

src/librustc_interface/util.rs

@@ -21,7 +21,6 @@ use rustc_plugin;
 use rustc_privacy;
 use rustc_resolve;
 use rustc_typeck;
-use std::collections::HashSet;
 use std::env;
 use std::env::consts::{DLL_PREFIX, DLL_SUFFIX};
 use std::io::{self, Write};