diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 116b1f16f7f..5e81db363ee 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -247,30 +247,28 @@ pub(crate) fn clean_middle_const<'tcx>(
     }
 }
 
-impl<'tcx> Clean<'tcx, Option<Lifetime>> for ty::Region<'tcx> {
-    fn clean(&self, _cx: &mut DocContext<'_>) -> Option<Lifetime> {
-        match **self {
-            ty::ReStatic => Some(Lifetime::statik()),
-            ty::ReLateBound(_, ty::BoundRegion { kind: ty::BrNamed(_, name), .. }) => {
-                if name != kw::UnderscoreLifetime { Some(Lifetime(name)) } else { None }
-            }
-            ty::ReEarlyBound(ref data) => {
-                if data.name != kw::UnderscoreLifetime {
-                    Some(Lifetime(data.name))
-                } else {
-                    None
-                }
-            }
-            ty::ReLateBound(..)
-            | ty::ReFree(..)
-            | ty::ReVar(..)
-            | ty::RePlaceholder(..)
-            | ty::ReEmpty(_)
-            | ty::ReErased => {
-                debug!("cannot clean region {:?}", self);
+pub(crate) fn clean_middle_region<'tcx>(region: ty::Region<'tcx>) -> Option<Lifetime> {
+    match *region {
+        ty::ReStatic => Some(Lifetime::statik()),
+        ty::ReLateBound(_, ty::BoundRegion { kind: ty::BrNamed(_, name), .. }) => {
+            if name != kw::UnderscoreLifetime { Some(Lifetime(name)) } else { None }
+        }
+        ty::ReEarlyBound(ref data) => {
+            if data.name != kw::UnderscoreLifetime {
+                Some(Lifetime(data.name))
+            } else {
                 None
             }
         }
+        ty::ReLateBound(..)
+        | ty::ReFree(..)
+        | ty::ReVar(..)
+        | ty::RePlaceholder(..)
+        | ty::ReEmpty(_)
+        | ty::ReErased => {
+            debug!("cannot clean region {:?}", region);
+            None
+        }
     }
 }
 
@@ -321,7 +319,7 @@ fn clean(&self, cx: &mut DocContext<'tcx>) -> Option<WherePredicate> {
             ty::PredicateKind::Trait(pred) => {
                 clean_poly_trait_predicate(bound_predicate.rebind(pred), cx)
             }
-            ty::PredicateKind::RegionOutlives(pred) => clean_region_outlives_predicate(pred, cx),
+            ty::PredicateKind::RegionOutlives(pred) => clean_region_outlives_predicate(pred),
             ty::PredicateKind::TypeOutlives(pred) => clean_type_outlives_predicate(pred, cx),
             ty::PredicateKind::Projection(pred) => Some(clean_projection_predicate(pred, cx)),
             ty::PredicateKind::ConstEvaluatable(..) => None,
@@ -358,7 +356,6 @@ fn clean_poly_trait_predicate<'tcx>(
 
 fn clean_region_outlives_predicate<'tcx>(
     pred: ty::OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>,
-    cx: &mut DocContext<'tcx>,
 ) -> Option<WherePredicate> {
     let ty::OutlivesPredicate(a, b) = pred;
 
@@ -367,8 +364,10 @@ fn clean_region_outlives_predicate<'tcx>(
     }
 
     Some(WherePredicate::RegionPredicate {
-        lifetime: a.clean(cx).expect("failed to clean lifetime"),
-        bounds: vec![GenericBound::Outlives(b.clean(cx).expect("failed to clean bounds"))],
+        lifetime: clean_middle_region(a).expect("failed to clean lifetime"),
+        bounds: vec![GenericBound::Outlives(
+            clean_middle_region(b).expect("failed to clean bounds"),
+        )],
     })
 }
 
@@ -384,7 +383,9 @@ fn clean_type_outlives_predicate<'tcx>(
 
     Some(WherePredicate::BoundPredicate {
         ty: clean_middle_ty(ty, cx, None),
-        bounds: vec![GenericBound::Outlives(lt.clean(cx).expect("failed to clean lifetimes"))],
+        bounds: vec![GenericBound::Outlives(
+            clean_middle_region(lt).expect("failed to clean lifetimes"),
+        )],
         bound_params: Vec::new(),
     })
 }
@@ -999,15 +1000,6 @@ fn clean(&self, cx: &mut DocContext<'tcx>) -> FnRetTy {
     }
 }
 
-impl<'tcx> Clean<'tcx, bool> for hir::IsAuto {
-    fn clean(&self, _: &mut DocContext<'tcx>) -> bool {
-        match *self {
-            hir::IsAuto::Yes => true,
-            hir::IsAuto::No => false,
-        }
-    }
-}
-
 impl<'tcx> Clean<'tcx, Path> for hir::TraitRef<'tcx> {
     fn clean(&self, cx: &mut DocContext<'tcx>) -> Path {
         let path = clean_path(self.path, cx);
@@ -1597,7 +1589,7 @@ pub(crate) fn clean_middle_ty<'tcx>(
         }
         ty::RawPtr(mt) => RawPointer(mt.mutbl, Box::new(clean_middle_ty(mt.ty, cx, None))),
         ty::Ref(r, ty, mutbl) => BorrowedRef {
-            lifetime: r.clean(cx),
+            lifetime: clean_middle_region(r),
             mutability: mutbl,
             type_: Box::new(clean_middle_ty(ty, cx, None)),
         },
@@ -1644,7 +1636,7 @@ pub(crate) fn clean_middle_ty<'tcx>(
 
             inline::record_extern_fqn(cx, did, ItemType::Trait);
 
-            let lifetime = reg.clean(cx);
+            let lifetime = clean_middle_region(*reg);
             let mut bounds = vec![];
 
             for did in dids {
@@ -1710,7 +1702,7 @@ pub(crate) fn clean_middle_ty<'tcx>(
                     let trait_ref = match bound_predicate.skip_binder() {
                         ty::PredicateKind::Trait(tr) => bound_predicate.rebind(tr.trait_ref),
                         ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(_ty, reg)) => {
-                            if let Some(r) = reg.clean(cx) {
+                            if let Some(r) = clean_middle_region(reg) {
                                 regions.push(GenericBound::Outlives(r));
                             }
                             return None;
diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs
index 621f70f0da9..43e71e90a6f 100644
--- a/src/librustdoc/clean/utils.rs
+++ b/src/librustdoc/clean/utils.rs
@@ -2,9 +2,9 @@
 use crate::clean::blanket_impl::BlanketImplFinder;
 use crate::clean::render_macro_matchers::render_macro_matcher;
 use crate::clean::{
-    clean_middle_const, clean_middle_ty, inline, Clean, Crate, ExternalCrate, Generic, GenericArg,
-    GenericArgs, ImportSource, Item, ItemKind, Lifetime, Path, PathSegment, Primitive,
-    PrimitiveType, Type, TypeBinding, Visibility,
+    clean_middle_const, clean_middle_region, clean_middle_ty, inline, Clean, Crate, ExternalCrate,
+    Generic, GenericArg, GenericArgs, ImportSource, Item, ItemKind, Lifetime, Path, PathSegment,
+    Primitive, PrimitiveType, Type, TypeBinding, Visibility,
 };
 use crate::core::DocContext;
 use crate::formats::item_type::ItemType;
@@ -86,7 +86,7 @@ pub(crate) fn substs_to_args<'tcx>(
         Vec::with_capacity(substs.len().saturating_sub(if skip_first { 1 } else { 0 }));
     ret_val.extend(substs.iter().filter_map(|kind| match kind.unpack() {
         GenericArgKind::Lifetime(lt) => {
-            Some(GenericArg::Lifetime(lt.clean(cx).unwrap_or(Lifetime::elided())))
+            Some(GenericArg::Lifetime(clean_middle_region(lt).unwrap_or(Lifetime::elided())))
         }
         GenericArgKind::Type(_) if skip_first => {
             skip_first = false;