From f784b77e84fd11b266df6c57f4077458e839d211 Mon Sep 17 00:00:00 2001
From: Aatif Syed <aatifsyedyp@gmail.com>
Date: Tue, 16 Sep 2025 23:29:13 +0100
Subject: [PATCH 1/4] mark: aatifsyed/peeking-next-vec


From ba24dfa5b05f8cefa5d5f95c36c02624ff5c9b72 Mon Sep 17 00:00:00 2001
From: Aatif Syed <aatifsyedyp@gmail.com>
Date: Tue, 16 Sep 2025 23:33:04 +0100
Subject: [PATCH 2/4] feat: impl PeekingNext for vec::IntoIter

---
 src/peeking_take_while.rs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/peeking_take_while.rs b/src/peeking_take_while.rs
index f3259a919..a84db647b 100644
--- a/src/peeking_take_while.rs
+++ b/src/peeking_take_while.rs
@@ -92,6 +92,17 @@ where
     }
 }
 
+#[cfg(feature = "use_alloc")]
+impl<T> PeekingNext for ::alloc::vec::IntoIter<T> {
+    fn peeking_next<F>(&mut self, accept: F) -> Option<Self::Item>
+    where
+        F: FnOnce(&Self::Item) -> bool,
+    {
+        self.as_slice().iter().peeking_next(|it| accept(*it))?;
+        self.next()
+    }
+}
+
 impl<T: Clone> PeekingNext for RepeatN<T> {
     fn peeking_next<F>(&mut self, accept: F) -> Option<Self::Item>
     where

From 6afbb36c3b9127fcf69dda85ec9b5bde85a92c7d Mon Sep 17 00:00:00 2001
From: Aatif Syed <aatifsyedyp@gmail.com>
Date: Fri, 26 Sep 2025 22:03:38 +0200
Subject: [PATCH 3/4] review: call slice::first

---
 src/peeking_take_while.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/peeking_take_while.rs b/src/peeking_take_while.rs
index b69a652a0..b8c0b990c 100644
--- a/src/peeking_take_while.rs
+++ b/src/peeking_take_while.rs
@@ -98,8 +98,10 @@ impl<T> PeekingNext for ::alloc::vec::IntoIter<T> {
     where
         F: FnOnce(&Self::Item) -> bool,
     {
-        self.as_slice().iter().peeking_next(|it| accept(*it))?;
-        self.next()
+        match accept(self.as_slice().first()?) {
+            true => self.next(),
+            false => None,
+        }
     }
 }
 

From 41de9d36615bc5691eabb63877f8c717728438ed Mon Sep 17 00:00:00 2001
From: Aatif Syed <aatifsyedyp@gmail.com>
Date: Fri, 26 Sep 2025 22:09:51 +0200
Subject: [PATCH 4/4] feat: impl PeekingNext for {vec::Drain, array::IntoIter,
 string::Drain}

---
 src/peeking_take_while.rs | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/src/peeking_take_while.rs b/src/peeking_take_while.rs
index b8c0b990c..e828b717d 100644
--- a/src/peeking_take_while.rs
+++ b/src/peeking_take_while.rs
@@ -105,6 +105,44 @@ impl<T> PeekingNext for ::alloc::vec::IntoIter<T> {
     }
 }
 
+#[cfg(feature = "use_alloc")]
+impl<'a, T> PeekingNext for ::alloc::vec::Drain<'a, T> {
+    fn peeking_next<F>(&mut self, accept: F) -> Option<Self::Item>
+    where
+        F: FnOnce(&Self::Item) -> bool,
+    {
+        match accept(self.as_slice().first()?) {
+            true => self.next(),
+            false => None,
+        }
+    }
+}
+
+#[cfg(feature = "use_alloc")]
+impl<'a> PeekingNext for ::alloc::string::Drain<'a> {
+    fn peeking_next<F>(&mut self, accept: F) -> Option<Self::Item>
+    where
+        F: FnOnce(&Self::Item) -> bool,
+    {
+        match accept(&self.as_str().chars().next()?) {
+            true => self.next(),
+            false => None,
+        }
+    }
+}
+
+impl<T, const N: usize> PeekingNext for ::core::array::IntoIter<T, N> {
+    fn peeking_next<F>(&mut self, accept: F) -> Option<Self::Item>
+    where
+        F: FnOnce(&Self::Item) -> bool,
+    {
+        match accept(self.as_slice().first()?) {
+            true => self.next(),
+            false => None,
+        }
+    }
+}
+
 impl<T: Clone> PeekingNext for RepeatN<T> {
     fn peeking_next<F>(&mut self, accept: F) -> Option<Self::Item>
     where