diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index d896df151a7dc..3ec73059721a2 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -1228,7 +1228,7 @@ Available lint options:
     fn sort_lint_groups(lints: Vec<(&'static str, Vec<lint::LintId>, bool)>)
                         -> Vec<(&'static str, Vec<lint::LintId>)> {
         let mut lints: Vec<_> = lints.into_iter().map(|(x, y, _)| (x, y)).collect();
-        lints.sort_by_key(|ref l| l.0);
+        lints.sort_by_key(|l| l.0);
         lints
     }
 
diff --git a/src/librustc_driver/profile/trace.rs b/src/librustc_driver/profile/trace.rs
index 4aaf5eb47f61c..970a860fdff2c 100644
--- a/src/librustc_driver/profile/trace.rs
+++ b/src/librustc_driver/profile/trace.rs
@@ -208,7 +208,7 @@ pub fn write_counts(count_file: &mut File, counts: &mut HashMap<String,QueryMetr
     for (ref cons, ref qm) in counts.iter() {
         data.push((cons.clone(), qm.count.clone(), qm.dur_total.clone(), qm.dur_self.clone()));
     };
-    data.sort_by_key(|&k| Reverse(k.3));
+    data.sort_by_key(|k| Reverse(k.3));
     for (cons, count, dur_total, dur_self) in data {
         write!(count_file, "{}, {}, {}, {}\n",
                cons, count,
diff --git a/src/librustc_mir/monomorphize/mod.rs b/src/librustc_mir/monomorphize/mod.rs
index e148bc3d9460c..30556759bd394 100644
--- a/src/librustc_mir/monomorphize/mod.rs
+++ b/src/librustc_mir/monomorphize/mod.rs
@@ -29,13 +29,13 @@ pub fn assert_symbols_are_distinct<'a, 'tcx, I>(tcx: TyCtxt<'a, 'tcx, 'tcx>, mon
         (mono_item, mono_item.symbol_name(tcx))
     }).collect();
 
-    (&mut symbols[..]).sort_by_key(|&sym| sym.1);
+    symbols.sort_by_key(|sym| sym.1);
 
-    for pair in (&symbols[..]).windows(2) {
+    for pair in symbols.windows(2) {
         let sym1 = &pair[0].1;
         let sym2 = &pair[1].1;
 
-        if *sym1 == *sym2 {
+        if sym1 == sym2 {
             let mono_item1 = pair[0].0;
             let mono_item2 = pair[1].0;
 
@@ -51,9 +51,7 @@ pub fn assert_symbols_are_distinct<'a, 'tcx, I>(tcx: TyCtxt<'a, 'tcx, 'tcx>, mon
                         span2
                     })
                 }
-                (Some(span), None) |
-                (None, Some(span)) => Some(span),
-                _ => None
+                (span1, span2) => span1.or(span2),
             };
 
             let error_message = format!("symbol `{}` is already defined", sym1);