Specialize count too

Author: a1phyr

Diff for: library/std/src/collections/hash/map.rs

@@ -2233,6 +2233,10 @@ impl<'a, K, V> Iterator for Iter<'a, K, V> {
         self.base.size_hint()
     }
     #[inline]
+    fn count(self) -> usize {
+        self.base.len()
+    }
+    #[inline]
     fn fold<B, F>(self, init: B, f: F) -> B
     where
         Self: Sized,
@@ -2265,6 +2269,10 @@ impl<'a, K, V> Iterator for IterMut<'a, K, V> {
         self.base.size_hint()
     }
     #[inline]
+    fn count(self) -> usize {
+        self.base.len()
+    }
+    #[inline]
     fn fold<B, F>(self, init: B, f: F) -> B
     where
         Self: Sized,
@@ -2307,6 +2315,10 @@ impl<K, V> Iterator for IntoIter<K, V> {
         self.base.size_hint()
     }
     #[inline]
+    fn count(self) -> usize {
+        self.base.len()
+    }
+    #[inline]
     fn fold<B, F>(self, init: B, f: F) -> B
     where
         Self: Sized,
@@ -2345,6 +2357,10 @@ impl<'a, K, V> Iterator for Keys<'a, K, V> {
         self.inner.size_hint()
     }
     #[inline]
+    fn count(self) -> usize {
+        self.inner.len()
+    }
+    #[inline]
     fn fold<B, F>(self, init: B, mut f: F) -> B
     where
         Self: Sized,
@@ -2376,6 +2392,10 @@ impl<'a, K, V> Iterator for Values<'a, K, V> {
         self.inner.size_hint()
     }
     #[inline]
+    fn count(self) -> usize {
+        self.inner.len()
+    }
+    #[inline]
     fn fold<B, F>(self, init: B, mut f: F) -> B
     where
         Self: Sized,
@@ -2407,6 +2427,10 @@ impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
         self.inner.size_hint()
     }
     #[inline]
+    fn count(self) -> usize {
+        self.inner.len()
+    }
+    #[inline]
     fn fold<B, F>(self, init: B, mut f: F) -> B
     where
         Self: Sized,
@@ -2445,6 +2469,10 @@ impl<K, V> Iterator for IntoKeys<K, V> {
         self.inner.size_hint()
     }
     #[inline]
+    fn count(self) -> usize {
+        self.inner.len()
+    }
+    #[inline]
     fn fold<B, F>(self, init: B, mut f: F) -> B
     where
         Self: Sized,
@@ -2483,6 +2511,10 @@ impl<K, V> Iterator for IntoValues<K, V> {
         self.inner.size_hint()
     }
     #[inline]
+    fn count(self) -> usize {
+        self.inner.len()
+    }
+    #[inline]
     fn fold<B, F>(self, init: B, mut f: F) -> B
     where
         Self: Sized,

Diff for: library/std/src/collections/hash/set.rs

@@ -1501,6 +1501,10 @@ impl<'a, K> Iterator for Iter<'a, K> {
         self.base.size_hint()
     }
     #[inline]
+    fn count(self) -> usize {
+        self.base.len()
+    }
+    #[inline]
     fn fold<B, F>(self, init: B, f: F) -> B
     where
         Self: Sized,
@@ -1539,6 +1543,10 @@ impl<K> Iterator for IntoIter<K> {
         self.base.size_hint()
     }
     #[inline]
+    fn count(self) -> usize {
+        self.base.len()
+    }
+    #[inline]
     fn fold<B, F>(self, init: B, f: F) -> B
     where
         Self: Sized,
@@ -1851,6 +1859,10 @@ where
         self.iter.size_hint()
     }
     #[inline]
+    fn count(self) -> usize {
+        self.iter.count()
+    }
+    #[inline]
     fn fold<B, F>(self, init: B, f: F) -> B
     where
         Self: Sized,