liballoc: elide some lifetimes.

src/liballoc/borrow.rs

@@ -183,9 +183,7 @@ pub enum Cow<'a, B: ?Sized + 'a>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> Clone for Cow<'a, B>
-    where B: ToOwned
-{
+impl<'a, B: ?Sized + ToOwned> Clone for Cow<'a, B> {
     fn clone(&self) -> Cow<'a, B> {
         match *self {
             Borrowed(b) => Borrowed(b),
@@ -208,9 +206,7 @@ impl<'a, B: ?Sized> Clone for Cow<'a, B>
     }
 }
 
-impl<'a, B: ?Sized> Cow<'a, B>
-    where B: ToOwned
-{
+impl<B: ?Sized + ToOwned> Cow<'_, B> {
     /// Acquires a mutable reference to the owned form of the data.
     ///
     /// Clones the data if it is not already owned.
@@ -286,9 +282,7 @@ impl<'a, B: ?Sized> Cow<'a, B>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> Deref for Cow<'a, B>
-    where B: ToOwned
-{
+impl<B: ?Sized + ToOwned> Deref for Cow<'_, B> {
     type Target = B;
 
     fn deref(&self) -> &B {
@@ -300,7 +294,7 @@ impl<'a, B: ?Sized> Deref for Cow<'a, B>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> Eq for Cow<'a, B> where B: Eq + ToOwned {}
+impl<B: ?Sized> Eq for Cow<'_, B> where B: Eq + ToOwned {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, B: ?Sized> Ord for Cow<'a, B>
@@ -334,7 +328,7 @@ impl<'a, B: ?Sized> PartialOrd for Cow<'a, B>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> fmt::Debug for Cow<'a, B>
+impl<B: ?Sized> fmt::Debug for Cow<'_, B>
     where B: fmt::Debug + ToOwned,
           <B as ToOwned>::Owned: fmt::Debug
 {
@@ -347,7 +341,7 @@ impl<'a, B: ?Sized> fmt::Debug for Cow<'a, B>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> fmt::Display for Cow<'a, B>
+impl<B: ?Sized> fmt::Display for Cow<'_, B>
     where B: fmt::Display + ToOwned,
           <B as ToOwned>::Owned: fmt::Display
 {
@@ -381,7 +375,7 @@ impl<'a, B: ?Sized> Hash for Cow<'a, B>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T: ?Sized + ToOwned> AsRef<T> for Cow<'a, T> {
+impl<T: ?Sized + ToOwned> AsRef<T> for Cow<'_, T> {
     fn as_ref(&self) -> &T {
         self
     }

src/liballoc/boxed.rs

@@ -739,7 +739,7 @@ impl<A, F> FnBox<A> for F
 
 #[unstable(feature = "fnbox",
            reason = "will be deprecated if and when `Box<FnOnce>` becomes usable", issue = "28796")]
-impl<'a, A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + 'a> {
+impl<A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + '_> {
     type Output = R;
 
     extern "rust-call" fn call_once(self, args: A) -> R {
@@ -749,7 +749,7 @@ impl<'a, A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + 'a> {
 
 #[unstable(feature = "fnbox",
            reason = "will be deprecated if and when `Box<FnOnce>` becomes usable", issue = "28796")]
-impl<'a, A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + Send + 'a> {
+impl<A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + Send + '_> {
     type Output = R;
 
     extern "rust-call" fn call_once(self, args: A) -> R {

src/liballoc/collections/binary_heap.rs

@@ -231,7 +231,7 @@ pub struct PeekMut<'a, T: 'a + Ord> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: Ord + fmt::Debug> fmt::Debug for PeekMut<'a, T> {
+impl<T: Ord + fmt::Debug> fmt::Debug for PeekMut<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_tuple("PeekMut")
          .field(&self.heap.data[0])
@@ -240,7 +240,7 @@ impl<'a, T: Ord + fmt::Debug> fmt::Debug for PeekMut<'a, T> {
 }
 
 #[stable(feature = "binary_heap_peek_mut", since = "1.12.0")]
-impl<'a, T: Ord> Drop for PeekMut<'a, T> {
+impl<T: Ord> Drop for PeekMut<'_, T> {
     fn drop(&mut self) {
         if self.sift {
             self.heap.sift_down(0);
@@ -249,15 +249,15 @@ impl<'a, T: Ord> Drop for PeekMut<'a, T> {
 }
 
 #[stable(feature = "binary_heap_peek_mut", since = "1.12.0")]
-impl<'a, T: Ord> Deref for PeekMut<'a, T> {
+impl<T: Ord> Deref for PeekMut<'_, T> {
     type Target = T;
     fn deref(&self) -> &T {
         &self.heap.data[0]
     }
 }
 
 #[stable(feature = "binary_heap_peek_mut", since = "1.12.0")]
-impl<'a, T: Ord> DerefMut for PeekMut<'a, T> {
+impl<T: Ord> DerefMut for PeekMut<'_, T> {
     fn deref_mut(&mut self) -> &mut T {
         &mut self.heap.data[0]
     }
@@ -912,7 +912,7 @@ impl<'a, T> Hole<'a, T> {
     }
 }
 
-impl<'a, T> Drop for Hole<'a, T> {
+impl<T> Drop for Hole<'_, T> {
     #[inline]
     fn drop(&mut self) {
         // fill the hole again
@@ -936,7 +936,7 @@ pub struct Iter<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
+impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_tuple("Iter")
          .field(&self.iter.as_slice())
@@ -976,14 +976,14 @@ impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> ExactSizeIterator for Iter<'a, T> {
+impl<T> ExactSizeIterator for Iter<'_, T> {
     fn is_empty(&self) -> bool {
         self.iter.is_empty()
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T> FusedIterator for Iter<'a, T> {}
+impl<T> FusedIterator for Iter<'_, T> {}
 
 /// An owning iterator over the elements of a `BinaryHeap`.
 ///
@@ -1054,7 +1054,7 @@ pub struct Drain<'a, T: 'a> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T: 'a> Iterator for Drain<'a, T> {
+impl<T> Iterator for Drain<'_, T> {
     type Item = T;
 
     #[inline]
@@ -1069,22 +1069,22 @@ impl<'a, T: 'a> Iterator for Drain<'a, T> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T: 'a> DoubleEndedIterator for Drain<'a, T> {
+impl<T> DoubleEndedIterator for Drain<'_, T> {
     #[inline]
     fn next_back(&mut self) -> Option<T> {
         self.iter.next_back()
     }
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T: 'a> ExactSizeIterator for Drain<'a, T> {
+impl<T> ExactSizeIterator for Drain<'_, T> {
     fn is_empty(&self) -> bool {
         self.iter.is_empty()
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T: 'a> FusedIterator for Drain<'a, T> {}
+impl<T> FusedIterator for Drain<'_, T> {}
 
 #[stable(feature = "binary_heap_extras_15", since = "1.5.0")]
 impl<T: Ord> From<Vec<T>> for BinaryHeap<T> {

src/liballoc/collections/btree/map.rs

@@ -279,7 +279,7 @@ pub struct Iter<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for Iter<'a, K, V> {
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Iter<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list().entries(self.clone()).finish()
     }
@@ -337,7 +337,7 @@ pub struct Keys<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, K: 'a + fmt::Debug, V: 'a> fmt::Debug for Keys<'a, K, V> {
+impl<K: fmt::Debug, V> fmt::Debug for Keys<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list().entries(self.clone()).finish()
     }
@@ -356,7 +356,7 @@ pub struct Values<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, K: 'a, V: 'a + fmt::Debug> fmt::Debug for Values<'a, K, V> {
+impl<K, V: fmt::Debug> fmt::Debug for Values<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list().entries(self.clone()).finish()
     }
@@ -389,7 +389,7 @@ pub struct Range<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for Range<'a, K, V> {
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Range<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list().entries(self.clone()).finish()
     }
@@ -412,7 +412,7 @@ pub struct RangeMut<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for RangeMut<'a, K, V> {
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for RangeMut<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let range = Range {
             front: self.front.reborrow(),
@@ -442,7 +442,7 @@ pub enum Entry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_btree_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug + Ord, V: 'a + Debug> Debug for Entry<'a, K, V> {
+impl<K: Debug + Ord, V: Debug> Debug for Entry<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             Vacant(ref v) => f.debug_tuple("Entry")
@@ -470,7 +470,7 @@ pub struct VacantEntry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_btree_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug + Ord, V: 'a> Debug for VacantEntry<'a, K, V> {
+impl<K: Debug + Ord, V> Debug for VacantEntry<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_tuple("VacantEntry")
          .field(self.key())
@@ -493,7 +493,7 @@ pub struct OccupiedEntry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_btree_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug + Ord, V: 'a + Debug> Debug for OccupiedEntry<'a, K, V> {
+impl<K: Debug + Ord, V: Debug> Debug for OccupiedEntry<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("OccupiedEntry")
          .field("key", self.key())
@@ -1202,7 +1202,7 @@ impl<'a, K: 'a, V: 'a> Iterator 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: 'a, V: 'a> DoubleEndedIterator for Iter<'a, K, V> {
@@ -1217,7 +1217,7 @@ impl<'a, K: 'a, V: 'a> DoubleEndedIterator for Iter<'a, K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K: 'a, V: 'a> ExactSizeIterator for Iter<'a, K, V> {
+impl<K, V> ExactSizeIterator for Iter<'_, K, V> {
     fn len(&self) -> usize {
         self.length
     }
@@ -1274,14 +1274,14 @@ impl<'a, K: 'a, V: 'a> DoubleEndedIterator for IterMut<'a, K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K: 'a, V: 'a> ExactSizeIterator for IterMut<'a, K, V> {
+impl<K, V> ExactSizeIterator for IterMut<'_, K, V> {
     fn len(&self) -> usize {
         self.length
     }
 }
 
 #[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 = "rust1", since = "1.0.0")]
 impl<K, V> IntoIterator for BTreeMap<K, V> {
@@ -1437,14 +1437,14 @@ impl<'a, K, V> DoubleEndedIterator 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> {
     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> Clone for Keys<'a, K, V> {
@@ -1474,14 +1474,14 @@ impl<'a, K, V> DoubleEndedIterator 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> {
     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 = "rust1", since = "1.0.0")]
 impl<'a, K, V> Clone for Values<'a, K, V> {
@@ -1524,15 +1524,14 @@ impl<'a, K, V> DoubleEndedIterator 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> {
     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> {}
 
 impl<'a, K, V> Range<'a, K, V> {
     unsafe fn next_unchecked(&mut self) -> (&'a K, &'a V) {
@@ -1610,7 +1609,7 @@ impl<'a, K, V> Range<'a, K, V> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Range<'a, K, V> {}
+impl<K, V> FusedIterator for Range<'_, K, V> {}
 
 #[stable(feature = "btree_range", since = "1.17.0")]
 impl<'a, K, V> Clone for Range<'a, K, V> {
@@ -1679,7 +1678,7 @@ impl<'a, K, V> DoubleEndedIterator for RangeMut<'a, K, V> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for RangeMut<'a, K, V> {}
+impl<K, V> FusedIterator for RangeMut<'_, K, V> {}
 
 impl<'a, K, V> RangeMut<'a, K, V> {
     unsafe fn next_back_unchecked(&mut self) -> (&'a K, &'a mut V) {
@@ -1790,7 +1789,7 @@ impl<K: Debug, V: Debug> Debug for BTreeMap<K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K: Ord, Q: ?Sized, V> Index<&'a Q> for BTreeMap<K, V>
+impl<K: Ord, Q: ?Sized, V> Index<&Q> for BTreeMap<K, V>
     where K: Borrow<Q>,
           Q: Ord
 {