+#[unstable(feature = "map_into_keys_values", issue = "75294")]
+impl<K, V> Iterator for IntoKeys<K, V> {
+ type Item = K;
+
+ fn next(&mut self) -> Option<K> {
+ self.inner.next().map(|(k, _)| k)
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.inner.size_hint()
+ }
+
+ fn last(mut self) -> Option<K> {
+ self.next_back()
+ }
+
+ fn min(mut self) -> Option<K> {
+ self.next()
+ }
+
+ fn max(mut self) -> Option<K> {
+ self.next_back()
+ }
+}
+
+#[unstable(feature = "map_into_keys_values", issue = "75294")]
+impl<K, V> DoubleEndedIterator for IntoKeys<K, V> {
+ fn next_back(&mut self) -> Option<K> {
+ self.inner.next_back().map(|(k, _)| k)
+ }
+}
+
+#[unstable(feature = "map_into_keys_values", issue = "75294")]
+impl<K, V> ExactSizeIterator for IntoKeys<K, V> {
+ fn len(&self) -> usize {
+ self.inner.len()
+ }
+}
+
+#[unstable(feature = "map_into_keys_values", issue = "75294")]
+impl<K, V> FusedIterator for IntoKeys<K, V> {}
+
+#[unstable(feature = "map_into_keys_values", issue = "75294")]
+impl<K, V> Iterator for IntoValues<K, V> {
+ type Item = V;
+
+ fn next(&mut self) -> Option<V> {
+ self.inner.next().map(|(_, v)| v)
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.inner.size_hint()
+ }
+
+ fn last(mut self) -> Option<V> {
+ self.next_back()
+ }
+}
+
+#[unstable(feature = "map_into_keys_values", issue = "75294")]
+impl<K, V> DoubleEndedIterator for IntoValues<K, V> {
+ fn next_back(&mut self) -> Option<V> {
+ self.inner.next_back().map(|(_, v)| v)
+ }
+}
+
+#[unstable(feature = "map_into_keys_values", issue = "75294")]
+impl<K, V> ExactSizeIterator for IntoValues<K, V> {
+ fn len(&self) -> usize {
+ self.inner.len()
+ }
+}
+
+#[unstable(feature = "map_into_keys_values", issue = "75294")]
+impl<K, V> FusedIterator for IntoValues<K, V> {}
+