From 9a92993d34a0d8ef7094edfdb0dc0ad456611b2e Mon Sep 17 00:00:00 2001
From: Bas Schoenmaeckers <b.schoenmaeckers@zanders.eu>
Date: Wed, 29 Jan 2025 10:16:08 +0100
Subject: [PATCH] Optimize `Iterator:last()` for `PyList` & `PyTuple`

---
 newsfragments/4878.added.md |  1 +
 src/types/list.rs           |  8 ++++++++
 src/types/tuple.rs          | 16 ++++++++++++++++
 3 files changed, 25 insertions(+)
 create mode 100644 newsfragments/4878.added.md

diff --git a/newsfragments/4878.added.md b/newsfragments/4878.added.md
new file mode 100644
index 00000000000..040c6d860e5
--- /dev/null
+++ b/newsfragments/4878.added.md
@@ -0,0 +1 @@
+Optimizes `last` for `BoundListIterator`, `BoundTupleIterator` and `BorrowedTupleIterator`
\ No newline at end of file
diff --git a/src/types/list.rs b/src/types/list.rs
index 76da36d00b9..7601f25f09a 100644
--- a/src/types/list.rs
+++ b/src/types/list.rs
@@ -750,6 +750,14 @@ impl<'py> Iterator for BoundListIterator<'py> {
             None
         })
     }
+
+    #[inline]
+    fn last(mut self) -> Option<Self::Item>
+    where
+        Self: Sized
+    {
+        self.next_back()
+    }
 }
 
 impl DoubleEndedIterator for BoundListIterator<'_> {
diff --git a/src/types/tuple.rs b/src/types/tuple.rs
index 8147b872af5..1121ab662ff 100644
--- a/src/types/tuple.rs
+++ b/src/types/tuple.rs
@@ -375,6 +375,14 @@ impl<'py> Iterator for BoundTupleIterator<'py> {
         let len = self.len();
         (len, Some(len))
     }
+
+    #[inline]
+    fn last(mut self) -> Option<Self::Item>
+    where
+        Self: Sized
+    {
+        self.next_back()
+    }
 }
 
 impl DoubleEndedIterator for BoundTupleIterator<'_> {
@@ -467,6 +475,14 @@ impl<'a, 'py> Iterator for BorrowedTupleIterator<'a, 'py> {
         let len = self.len();
         (len, Some(len))
     }
+
+    #[inline]
+    fn last(mut self) -> Option<Self::Item>
+    where
+        Self: Sized
+    {
+        self.next_back()
+    }
 }
 
 impl DoubleEndedIterator for BorrowedTupleIterator<'_, '_> {