3 files changed, 7 insertions, 13 deletions
diff --git a/compiler/rustc_incremental/src/assert_dep_graph.rs b/compiler/rustc_incremental/src/assert_dep_graph.rs
index 69e482ce8..33a9a0cab 100644
--- a/compiler/rustc_incremental/src/assert_dep_graph.rs
+++ b/compiler/rustc_incremental/src/assert_dep_graph.rs
@@ -249,7 +249,7 @@ fn dump_graph(query: &DepGraphQuery) {
         // dump a .txt file with just the edges:
         let txt_path = format!("{}.txt", path);
         let mut file = BufWriter::new(File::create(&txt_path).unwrap());
-        for &(ref source, ref target) in &edges {
+        for (source, target) in &edges {
             write!(file, "{:?} -> {:?}\n", source, target).unwrap();
         }
     }
@@ -368,7 +368,7 @@ fn walk_between<'q>(
 ) -> FxHashSet<DepKind> {
     // This is a bit tricky. We want to include a node only if it is:
     // (a) reachable from a source and (b) will reach a target. And we
-    // have to be careful about cycles etc.  Luckily efficiency is not
+    // have to be careful about cycles etc. Luckily efficiency is not
     // a big concern!
 
     #[derive(Copy, Clone, PartialEq)]
@@ -432,10 +432,7 @@ fn walk_between<'q>(
     }
 }
 
-fn filter_edges<'q>(
-    query: &'q DepGraphQuery,
-    nodes: &FxHashSet<DepKind>,
-) -> Vec<(DepKind, DepKind)> {
+fn filter_edges(query: &DepGraphQuery, nodes: &FxHashSet<DepKind>) -> Vec<(DepKind, DepKind)> {
     let uniq: FxHashSet<_> = query
         .edges()
         .into_iter()
diff --git a/compiler/rustc_incremental/src/persist/dirty_clean.rs b/compiler/rustc_incremental/src/persist/dirty_clean.rs
index a8acaf659..ed7b272b1 100644
--- a/compiler/rustc_incremental/src/persist/dirty_clean.rs
+++ b/compiler/rustc_incremental/src/persist/dirty_clean.rs
@@ -1,4 +1,4 @@
-//! Debugging code to test fingerprints computed for query results.  For each node marked with
+//! Debugging code to test fingerprints computed for query results. For each node marked with
 //! `#[rustc_clean]` we will compare the fingerprint from the current and from the previous
 //! compilation session as appropriate:
 //!
@@ -30,8 +30,6 @@ use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
-use std::iter::FromIterator;
-use std::vec::Vec;
 
 const LOADED_FROM_DISK: Symbol = sym::loaded_from_disk;
 const EXCEPT: Symbol = sym::except;
diff --git a/compiler/rustc_incremental/src/persist/fs.rs b/compiler/rustc_incremental/src/persist/fs.rs
index 97ebed058..1fd2b9b0d 100644
--- a/compiler/rustc_incremental/src/persist/fs.rs
+++ b/compiler/rustc_incremental/src/persist/fs.rs
@@ -113,7 +113,6 @@ use rustc_span::Symbol;
 
 use std::fs as std_fs;
 use std::io::{self, ErrorKind};
-use std::mem;
 use std::path::{Path, PathBuf};
 use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
@@ -305,7 +304,7 @@ pub fn prepare_session_directory(
             }
 
             delete_session_dir_lock_file(sess, &lock_file_path);
-            mem::drop(directory_lock);
+            drop(directory_lock);
         }
     }
 }
@@ -864,7 +863,7 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
 
                     // Let's make it explicit that the file lock is released at this point,
                     // or rather, that we held on to it until here
-                    mem::drop(lock);
+                    drop(lock);
                 }
                 Err(_) => {
                     debug!(
@@ -898,7 +897,7 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
 
         // Let's make it explicit that the file lock is released at this point,
         // or rather, that we held on to it until here
-        mem::drop(lock);
+        drop(lock);
     }
 
     Ok(())