From 29a6a9e8d23e9dc178851f0bc49e2b46afcc8c49 Mon Sep 17 00:00:00 2001
From: Ulrik Sverdrup <bluss@users.noreply.github.com>
Date: Mon, 3 Apr 2017 02:03:12 +0200
Subject: [PATCH 1/2] iter: Use underlying find/rfind for the same methods in
 Rev

---
 src/libcore/iter/mod.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/libcore/iter/mod.rs b/src/libcore/iter/mod.rs
index 04394e0a3a876..273f9d0e6f6d3 100644
--- a/src/libcore/iter/mod.rs
+++ b/src/libcore/iter/mod.rs
@@ -358,12 +358,24 @@ impl<I> Iterator for Rev<I> where I: DoubleEndedIterator {
     fn next(&mut self) -> Option<<I as Iterator>::Item> { self.iter.next_back() }
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() }
+
+    fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
+        where P: FnMut(&Self::Item) -> bool
+    {
+        self.iter.rfind(predicate)
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<I> DoubleEndedIterator for Rev<I> where I: DoubleEndedIterator {
     #[inline]
     fn next_back(&mut self) -> Option<<I as Iterator>::Item> { self.iter.next() }
+
+    fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>
+        where P: FnMut(&Self::Item) -> bool
+    {
+        self.iter.find(predicate)
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]

From 74f8ea263e119f947264f373229a8f1a940ae877 Mon Sep 17 00:00:00 2001
From: Ulrik Sverdrup <bluss@users.noreply.github.com>
Date: Mon, 3 Apr 2017 02:03:12 +0200
Subject: [PATCH 2/2] iter: Simplification in rfind's provided implementation

- Prefer simpler constructs instead of going through &mut I's Iterator
  implementation.
---
 src/libcore/iter/traits.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/libcore/iter/traits.rs b/src/libcore/iter/traits.rs
index 34f14ef53f893..798dda1992813 100644
--- a/src/libcore/iter/traits.rs
+++ b/src/libcore/iter/traits.rs
@@ -467,7 +467,7 @@ pub trait DoubleEndedIterator: Iterator {
         Self: Sized,
         P: FnMut(&Self::Item) -> bool
     {
-        for x in self.by_ref().rev() {
+        while let Some(x) = self.next_back() {
             if predicate(&x) { return Some(x) }
         }
         None