Use more impl header lifetime elision

There are two big categories of changes in here

- Removing lifetimes from common traits that can essentially never user a lifetime from an input (particularly `Drop` & `Debug`)
- Forwarding impls that are only possible because the lifetime doesn't matter (like `impl<R: Read + ?Sized> Read for &mut R`)

I omitted things that seemed like they could be more controversial, like the handful of iterators that have a `Item: 'static` despite the iterator having a lifetime or the `PartialEq` implementations where the flipped one cannot elide the lifetime.

3 files changed, 73 insertions, 73 deletions

diff --git a/src/libstd/collections/hash/map.rs b/src/libstd/collections/hash/map.rs
index 91c4e990e00..3dd299bf0ef 100644
--- a/src/libstd/collections/hash/map.rs
+++ b/src/libstd/collections/hash/map.rs
@@ -1641,7 +1641,7 @@ impl<K, V, S> Default for HashMap<K, V, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, Q: ?Sized, V, S> Index<&'a Q> for HashMap<K, V, S>
+impl<K, Q: ?Sized, V, S> Index<&Q> for HashMap<K, V, S>
     where K: Eq + Hash + Borrow<Q>,
           Q: Eq + Hash,
           S: BuildHasher
@@ -1673,14 +1673,14 @@ pub struct Iter<'a, K: 'a, V: 'a> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Iter<'a, K, V> {
-    fn clone(&self) -> Iter<'a, K, V> {
+impl<K, V> Clone for Iter<'_, K, V> {
+    fn clone(&self) -> Self {
         Iter { inner: self.inner.clone() }
     }
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K: Debug, V: Debug> fmt::Debug for Iter<'a, K, V> {
+impl<K: Debug, V: Debug> fmt::Debug for Iter<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list()
             .entries(self.clone())
@@ -1726,14 +1726,14 @@ pub struct Keys<'a, K: 'a, V: 'a> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Keys<'a, K, V> {
-    fn clone(&self) -> Keys<'a, K, V> {
+impl<K, V> Clone for Keys<'_, K, V> {
+    fn clone(&self) -> Self {
         Keys { inner: self.inner.clone() }
     }
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K: Debug, V> fmt::Debug for Keys<'a, K, V> {
+impl<K: Debug, V> fmt::Debug for Keys<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list()
             .entries(self.clone())
@@ -1755,14 +1755,14 @@ pub struct Values<'a, K: 'a, V: 'a> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Values<'a, K, V> {
-    fn clone(&self) -> Values<'a, K, V> {
+impl<K, V> Clone for Values<'_, K, V> {
+    fn clone(&self) -> Self {
         Values { inner: self.inner.clone() }
     }
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K, V: Debug> fmt::Debug for Values<'a, K, V> {
+impl<K, V: Debug> fmt::Debug for Values<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list()
             .entries(self.clone())
@@ -2241,7 +2241,7 @@ impl<'a, K, V, S> RawVacantEntryMut<'a, K, V, S> {
 }
 
 #[unstable(feature = "hash_raw_entry", issue = "56167")]
-impl<'a, K, V, S> Debug for RawEntryBuilderMut<'a, K, V, S> {
+impl<K, V, S> Debug for RawEntryBuilderMut<'_, K, V, S> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("RawEntryBuilder")
          .finish()
@@ -2249,7 +2249,7 @@ impl<'a, K, V, S> Debug for RawEntryBuilderMut<'a, K, V, S> {
 }
 
 #[unstable(feature = "hash_raw_entry", issue = "56167")]
-impl<'a, K: Debug, V: Debug, S> Debug for RawEntryMut<'a, K, V, S> {
+impl<K: Debug, V: Debug, S> Debug for RawEntryMut<'_, K, V, S> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             RawEntryMut::Vacant(ref v) => {
@@ -2267,7 +2267,7 @@ impl<'a, K: Debug, V: Debug, S> Debug for RawEntryMut<'a, K, V, S> {
 }
 
 #[unstable(feature = "hash_raw_entry", issue = "56167")]
-impl<'a, K: Debug, V: Debug> Debug for RawOccupiedEntryMut<'a, K, V> {
+impl<K: Debug, V: Debug> Debug for RawOccupiedEntryMut<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("RawOccupiedEntryMut")
          .field("key", self.key())
@@ -2277,7 +2277,7 @@ impl<'a, K: Debug, V: Debug> Debug for RawOccupiedEntryMut<'a, K, V> {
 }
 
 #[unstable(feature = "hash_raw_entry", issue = "56167")]
-impl<'a, K, V, S> Debug for RawVacantEntryMut<'a, K, V, S> {
+impl<K, V, S> Debug for RawVacantEntryMut<'_, K, V, S> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("RawVacantEntryMut")
          .finish()
@@ -2285,7 +2285,7 @@ impl<'a, K, V, S> Debug for RawVacantEntryMut<'a, K, V, S> {
 }
 
 #[unstable(feature = "hash_raw_entry", issue = "56167")]
-impl<'a, K, V, S> Debug for RawEntryBuilder<'a, K, V, S> {
+impl<K, V, S> Debug for RawEntryBuilder<'_, K, V, S> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("RawEntryBuilder")
          .finish()
@@ -2312,7 +2312,7 @@ pub enum Entry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_hash_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug, V: 'a + Debug> Debug for Entry<'a, K, V> {
+impl<K: Debug, V: Debug> Debug for Entry<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             Vacant(ref v) => {
@@ -2340,7 +2340,7 @@ pub struct OccupiedEntry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_hash_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug, V: 'a + Debug> Debug for OccupiedEntry<'a, K, V> {
+impl<K: Debug, V: Debug> Debug for OccupiedEntry<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("OccupiedEntry")
             .field("key", self.key())
@@ -2361,7 +2361,7 @@ pub struct VacantEntry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_hash_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug, V: 'a> Debug for VacantEntry<'a, K, V> {
+impl<K: Debug, V> Debug for VacantEntry<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_tuple("VacantEntry")
             .field(self.key())
@@ -2448,7 +2448,7 @@ impl<'a, K, V> Iterator for Iter<'a, K, V> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Iter<'a, K, V> {
+impl<K, V> ExactSizeIterator for Iter<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
@@ -2456,7 +2456,7 @@ impl<'a, K, V> ExactSizeIterator for Iter<'a, K, V> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Iter<'a, K, V> {}
+impl<K, V> FusedIterator for Iter<'_, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, K, V> Iterator for IterMut<'a, K, V> {
@@ -2472,17 +2472,17 @@ impl<'a, K, V> Iterator for IterMut<'a, K, V> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for IterMut<'a, K, V> {
+impl<K, V> ExactSizeIterator for IterMut<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for IterMut<'a, K, V> {}
+impl<K, V> FusedIterator for IterMut<'_, K, V> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K, V> fmt::Debug for IterMut<'a, K, V>
+impl<K, V> fmt::Debug for IterMut<'_, K, V>
     where K: fmt::Debug,
           V: fmt::Debug,
 {
@@ -2539,14 +2539,14 @@ impl<'a, K, V> Iterator for Keys<'a, K, V> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Keys<'a, K, V> {
+impl<K, V> ExactSizeIterator for Keys<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Keys<'a, K, V> {}
+impl<K, V> FusedIterator for Keys<'_, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, K, V> Iterator for Values<'a, K, V> {
@@ -2562,14 +2562,14 @@ impl<'a, K, V> Iterator for Values<'a, K, V> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Values<'a, K, V> {
+impl<K, V> ExactSizeIterator for Values<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Values<'a, K, V> {}
+impl<K, V> FusedIterator for Values<'_, K, V> {}
 
 #[stable(feature = "map_values_mut", since = "1.10.0")]
 impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
@@ -2585,17 +2585,17 @@ impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
     }
 }
 #[stable(feature = "map_values_mut", since = "1.10.0")]
-impl<'a, K, V> ExactSizeIterator for ValuesMut<'a, K, V> {
+impl<K, V> ExactSizeIterator for ValuesMut<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for ValuesMut<'a, K, V> {}
+impl<K, V> FusedIterator for ValuesMut<'_, K, V> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K, V> fmt::Debug for ValuesMut<'a, K, V>
+impl<K, V> fmt::Debug for ValuesMut<'_, K, V>
     where K: fmt::Debug,
           V: fmt::Debug,
 {
@@ -2620,17 +2620,17 @@ impl<'a, K, V> Iterator for Drain<'a, K, V> {
     }
 }
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, K, V> ExactSizeIterator for Drain<'a, K, V> {
+impl<K, V> ExactSizeIterator for Drain<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Drain<'a, K, V> {}
+impl<K, V> FusedIterator for Drain<'_, K, V> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K, V> fmt::Debug for Drain<'a, K, V>
+impl<K, V> fmt::Debug for Drain<'_, K, V>
     where K: fmt::Debug,
           V: fmt::Debug,
 {
diff --git a/src/libstd/collections/hash/set.rs b/src/libstd/collections/hash/set.rs
index c55dd049ec6..808f5f4a4f8 100644
--- a/src/libstd/collections/hash/set.rs
+++ b/src/libstd/collections/hash/set.rs
@@ -1112,8 +1112,8 @@ impl<T, S> IntoIterator for HashSet<T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K> Clone for Iter<'a, K> {
-    fn clone(&self) -> Iter<'a, K> {
+impl<K> Clone for Iter<'_, K> {
+    fn clone(&self) -> Self {
         Iter { iter: self.iter.clone() }
     }
 }
@@ -1129,16 +1129,16 @@ impl<'a, K> Iterator for Iter<'a, K> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K> ExactSizeIterator for Iter<'a, K> {
+impl<K> ExactSizeIterator for Iter<'_, K> {
     fn len(&self) -> usize {
         self.iter.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K> FusedIterator for Iter<'a, K> {}
+impl<K> FusedIterator for Iter<'_, K> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K: fmt::Debug> fmt::Debug for Iter<'a, K> {
+impl<K: fmt::Debug> fmt::Debug for Iter<'_, K> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list().entries(self.clone()).finish()
     }
@@ -1187,16 +1187,16 @@ impl<'a, K> Iterator for Drain<'a, K> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K> ExactSizeIterator for Drain<'a, K> {
+impl<K> ExactSizeIterator for Drain<'_, K> {
     fn len(&self) -> usize {
         self.iter.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K> FusedIterator for Drain<'a, K> {}
+impl<K> FusedIterator for Drain<'_, K> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K: fmt::Debug> fmt::Debug for Drain<'a, K> {
+impl<K: fmt::Debug> fmt::Debug for Drain<'_, K> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let entries_iter = self.iter
             .inner
@@ -1207,8 +1207,8 @@ impl<'a, K: fmt::Debug> fmt::Debug for Drain<'a, K> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S> Clone for Intersection<'a, T, S> {
-    fn clone(&self) -> Intersection<'a, T, S> {
+impl<T, S> Clone for Intersection<'_, T, S> {
+    fn clone(&self) -> Self {
         Intersection { iter: self.iter.clone(), ..*self }
     }
 }
@@ -1236,7 +1236,7 @@ impl<'a, T, S> Iterator for Intersection<'a, T, S>
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, T, S> fmt::Debug for Intersection<'a, T, S>
+impl<T, S> fmt::Debug for Intersection<'_, T, S>
     where T: fmt::Debug + Eq + Hash,
           S: BuildHasher
 {
@@ -1246,15 +1246,15 @@ impl<'a, T, S> fmt::Debug for Intersection<'a, T, S>
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T, S> FusedIterator for Intersection<'a, T, S>
+impl<T, S> FusedIterator for Intersection<'_, T, S>
     where T: Eq + Hash,
           S: BuildHasher
 {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S> Clone for Difference<'a, T, S> {
-    fn clone(&self) -> Difference<'a, T, S> {
+impl<T, S> Clone for Difference<'_, T, S> {
+    fn clone(&self) -> Self {
         Difference { iter: self.iter.clone(), ..*self }
     }
 }
@@ -1282,14 +1282,14 @@ impl<'a, T, S> Iterator for Difference<'a, T, S>
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T, S> FusedIterator for Difference<'a, T, S>
+impl<T, S> FusedIterator for Difference<'_, T, S>
     where T: Eq + Hash,
           S: BuildHasher
 {
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, T, S> fmt::Debug for Difference<'a, T, S>
+impl<T, S> fmt::Debug for Difference<'_, T, S>
     where T: fmt::Debug + Eq + Hash,
           S: BuildHasher
 {
@@ -1299,8 +1299,8 @@ impl<'a, T, S> fmt::Debug for Difference<'a, T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S> Clone for SymmetricDifference<'a, T, S> {
-    fn clone(&self) -> SymmetricDifference<'a, T, S> {
+impl<T, S> Clone for SymmetricDifference<'_, T, S> {
+    fn clone(&self) -> Self {
         SymmetricDifference { iter: self.iter.clone() }
     }
 }
@@ -1321,14 +1321,14 @@ impl<'a, T, S> Iterator for SymmetricDifference<'a, T, S>
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T, S> FusedIterator for SymmetricDifference<'a, T, S>
+impl<T, S> FusedIterator for SymmetricDifference<'_, T, S>
     where T: Eq + Hash,
           S: BuildHasher
 {
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, T, S> fmt::Debug for SymmetricDifference<'a, T, S>
+impl<T, S> fmt::Debug for SymmetricDifference<'_, T, S>
     where T: fmt::Debug + Eq + Hash,
           S: BuildHasher
 {
@@ -1338,21 +1338,21 @@ impl<'a, T, S> fmt::Debug for SymmetricDifference<'a, T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S> Clone for Union<'a, T, S> {
-    fn clone(&self) -> Union<'a, T, S> {
+impl<T, S> Clone for Union<'_, T, S> {
+    fn clone(&self) -> Self {
         Union { iter: self.iter.clone() }
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T, S> FusedIterator for Union<'a, T, S>
+impl<T, S> FusedIterator for Union<'_, T, S>
     where T: Eq + Hash,
           S: BuildHasher
 {
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, T, S> fmt::Debug for Union<'a, T, S>
+impl<T, S> fmt::Debug for Union<'_, T, S>
     where T: fmt::Debug + Eq + Hash,
           S: BuildHasher
 {
diff --git a/src/libstd/collections/hash/table.rs b/src/libstd/collections/hash/table.rs
index 28beb80612c..d5b75b22499 100644
--- a/src/libstd/collections/hash/table.rs
+++ b/src/libstd/collections/hash/table.rs
@@ -296,7 +296,7 @@ pub trait Put<K, V> {
 }
 
 
-impl<'t, K, V> Put<K, V> for &'t mut RawTable<K, V> {
+impl<K, V> Put<K, V> for &mut RawTable<K, V> {
     unsafe fn borrow_table_mut(&mut self) -> &mut RawTable<K, V> {
         *self
     }
@@ -865,8 +865,8 @@ struct RawBuckets<'a, K, V> {
 }
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
-impl<'a, K, V> Clone for RawBuckets<'a, K, V> {
-    fn clone(&self) -> RawBuckets<'a, K, V> {
+impl<K, V> Clone for RawBuckets<'_, K, V> {
+    fn clone(&self) -> Self {
         RawBuckets {
             raw: self.raw,
             elems_left: self.elems_left,
@@ -901,7 +901,7 @@ impl<'a, K, V> Iterator for RawBuckets<'a, K, V> {
     }
 }
 
-impl<'a, K, V> ExactSizeIterator for RawBuckets<'a, K, V> {
+impl<K, V> ExactSizeIterator for RawBuckets<'_, K, V> {
     fn len(&self) -> usize {
         self.elems_left
     }
@@ -912,12 +912,12 @@ pub struct Iter<'a, K: 'a, V: 'a> {
     iter: RawBuckets<'a, K, V>,
 }
 
-unsafe impl<'a, K: Sync, V: Sync> Sync for Iter<'a, K, V> {}
-unsafe impl<'a, K: Sync, V: Sync> Send for Iter<'a, K, V> {}
+unsafe impl<K: Sync, V: Sync> Sync for Iter<'_, K, V> {}
+unsafe impl<K: Sync, V: Sync> Send for Iter<'_, K, V> {}
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
-impl<'a, K, V> Clone for Iter<'a, K, V> {
-    fn clone(&self) -> Iter<'a, K, V> {
+impl<K, V> Clone for Iter<'_, K, V> {
+    fn clone(&self) -> Self {
         Iter {
             iter: self.iter.clone(),
         }
@@ -931,10 +931,10 @@ pub struct IterMut<'a, K: 'a, V: 'a> {
     _marker: marker::PhantomData<&'a mut V>,
 }
 
-unsafe impl<'a, K: Sync, V: Sync> Sync for IterMut<'a, K, V> {}
+unsafe impl<K: Sync, V: Sync> Sync for IterMut<'_, K, V> {}
 // Both K: Sync and K: Send are correct for IterMut's Send impl,
 // but Send is the more useful bound
-unsafe impl<'a, K: Send, V: Send> Send for IterMut<'a, K, V> {}
+unsafe impl<K: Send, V: Send> Send for IterMut<'_, K, V> {}
 
 impl<'a, K: 'a, V: 'a> IterMut<'a, K, V> {
     pub fn iter(&self) -> Iter<K, V> {
@@ -968,8 +968,8 @@ pub struct Drain<'a, K: 'a, V: 'a> {
     marker: marker::PhantomData<&'a RawTable<K, V>>,
 }
 
-unsafe impl<'a, K: Sync, V: Sync> Sync for Drain<'a, K, V> {}
-unsafe impl<'a, K: Send, V: Send> Send for Drain<'a, K, V> {}
+unsafe impl<K: Sync, V: Sync> Sync for Drain<'_, K, V> {}
+unsafe impl<K: Send, V: Send> Send for Drain<'_, K, V> {}
 
 impl<'a, K, V> Drain<'a, K, V> {
     pub fn iter(&self) -> Iter<K, V> {
@@ -994,7 +994,7 @@ impl<'a, K, V> Iterator for Iter<'a, K, V> {
     }
 }
 
-impl<'a, K, V> ExactSizeIterator for Iter<'a, K, V> {
+impl<K, V> ExactSizeIterator for Iter<'_, K, V> {
     fn len(&self) -> usize {
         self.iter.len()
     }
@@ -1015,7 +1015,7 @@ impl<'a, K, V> Iterator for IterMut<'a, K, V> {
     }
 }
 
-impl<'a, K, V> ExactSizeIterator for IterMut<'a, K, V> {
+impl<K, V> ExactSizeIterator for IterMut<'_, K, V> {
     fn len(&self) -> usize {
         self.iter.len()
     }
@@ -1064,13 +1064,13 @@ impl<'a, K, V> Iterator for Drain<'a, K, V> {
     }
 }
 
-impl<'a, K, V> ExactSizeIterator for Drain<'a, K, V> {
+impl<K, V> ExactSizeIterator for Drain<'_, K, V> {
     fn len(&self) -> usize {
         self.iter.len()
     }
 }
 
-impl<'a, K: 'a, V: 'a> Drop for Drain<'a, K, V> {
+impl<K, V> Drop for Drain<'_, K, V> {
     fn drop(&mut self) {
         self.for_each(drop);
     }