From aee04824d6e9cd63d5bb2066bfe39245fbf9a682 Mon Sep 17 00:00:00 2001
From: Josh Stone <cuviper@gmail.com>
Date: Fri, 30 Jul 2021 16:07:38 -0700
Subject: [PATCH] impl ExactSizeIterator for Drain

---
 src/map.rs | 6 ++++++
 src/set.rs | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/src/map.rs b/src/map.rs
index 9b833c3..fad30cf 100644
--- a/src/map.rs
+++ b/src/map.rs
@@ -1098,6 +1098,12 @@ impl<K, V> DoubleEndedIterator for Drain<'_, K, V> {
     double_ended_iterator_methods!(Bucket::key_value);
 }
 
+impl<K, V> ExactSizeIterator for Drain<'_, K, V> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
 impl<'a, K, V, S> IntoIterator for &'a IndexMap<K, V, S> {
     type Item = (&'a K, &'a V);
     type IntoIter = Iter<'a, K, V>;
diff --git a/src/set.rs b/src/set.rs
index f559999..404af27 100644
--- a/src/set.rs
+++ b/src/set.rs
@@ -786,6 +786,12 @@ impl<T> DoubleEndedIterator for Drain<'_, T> {
     double_ended_iterator_methods!(Bucket::key);
 }
 
+impl<T> ExactSizeIterator for Drain<'_, T> {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
 impl<'a, T, S> IntoIterator for &'a IndexSet<T, S> {
     type Item = &'a T;
     type IntoIter = Iter<'a, T>;