Remove redundant clone

src/librustc/hir/print.rs

@@ -180,7 +180,7 @@ impl<'a> State<'a> {
         State {
             s: pp::mk_printer(out, default_columns),
             cm: Some(cm),
-            comments: comments.clone(),
+            comments,
             literals: literals.unwrap_or_default().into_iter().peekable(),
             cur_cmnt: 0,
             boxes: Vec::new(),

src/librustc/ich/caching_codemap_view.rs

@@ -44,7 +44,7 @@ impl<'cm> CachingSourceMapView<'cm> {
 
         CachingSourceMapView {
             source_map,
-            line_cache: [entry.clone(), entry.clone(), entry.clone()],
+            line_cache: [entry.clone(), entry.clone(), entry],
             time_stamp: 0,
         }
     }

src/librustc/traits/project.rs

@@ -340,7 +340,7 @@ impl<'a, 'b, 'gcx, 'tcx> AssociatedTypeNormalizer<'a, 'b, 'gcx, 'tcx> {
         let value = self.selcx.infcx().resolve_type_vars_if_possible(value);
 
         if !value.has_projections() {
-            value.clone()
+            value
         } else {
             value.fold_with(self)
         }

src/librustc/ty/sty.rs

@@ -967,7 +967,7 @@ impl<'tcx> PolyFnSig<'tcx> {
         self.map_bound_ref(|fn_sig| fn_sig.inputs_and_output)
     }
     pub fn output(&self) -> ty::Binder<Ty<'tcx>> {
-        self.map_bound_ref(|fn_sig| fn_sig.output().clone())
+        self.map_bound_ref(|fn_sig| fn_sig.output())
     }
     pub fn variadic(&self) -> bool {
         self.skip_binder().variadic

src/librustc_mir/hair/pattern/_match.rs

@@ -1048,7 +1048,7 @@ pub fn is_useful<'p, 'a: 'p, 'tcx: 'a>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
     if let Some(constructors) = pat_constructors(cx, v[0], pcx) {
         debug!("is_useful - expanding constructors: {:#?}", constructors);
         split_grouped_constructors(cx.tcx, constructors, matrix, pcx.ty).into_iter().map(|c|
-            is_useful_specialized(cx, matrix, v, c.clone(), pcx.ty, witness)
+            is_useful_specialized(cx, matrix, v, c, pcx.ty, witness)
         ).find(|result| result.is_useful()).unwrap_or(NotUseful)
     } else {
         debug!("is_useful - expanding wildcard");
@@ -1096,7 +1096,7 @@ pub fn is_useful<'p, 'a: 'p, 'tcx: 'a>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
 
         if missing_ctors.is_empty() && !is_non_exhaustive {
             split_grouped_constructors(cx.tcx, all_ctors, matrix, pcx.ty).into_iter().map(|c| {
-                is_useful_specialized(cx, matrix, v, c.clone(), pcx.ty, witness)
+                is_useful_specialized(cx, matrix, v, c, pcx.ty, witness)
             }).find(|result| result.is_useful()).unwrap_or(NotUseful)
         } else {
             let matrix = rows.iter().filter_map(|r| {

src/libsyntax/fold.rs

@@ -965,7 +965,7 @@ pub fn noop_fold_item_kind<T: Folder>(i: ItemKind, folder: &mut T) -> ItemKind {
             polarity,
             defaultness,
             folder.fold_generics(generics),
-            ifce.map(|trait_ref| folder.fold_trait_ref(trait_ref.clone())),
+            ifce.map(|trait_ref| folder.fold_trait_ref(trait_ref)),
             folder.fold_ty(ty),
             impl_items.move_flat_map(|item| folder.fold_impl_item(item)),
         ),