From fa9bfebfc9256369c03cbe8bba2e737de3cb38fc Mon Sep 17 00:00:00 2001
From: Stein Somers <git@steinsomers.be>
Date: Tue, 4 Feb 2020 22:19:05 +0100
Subject: Fix and test implementation of BTreeMap's first_entry, last_entry,
 pop_first, pop_last

---
 src/liballoc/collections/btree/map.rs | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

(limited to 'src/liballoc/collections')

diff --git a/src/liballoc/collections/btree/map.rs b/src/liballoc/collections/btree/map.rs
index 8eabc177304..c1778f2065d 100644
--- a/src/liballoc/collections/btree/map.rs
+++ b/src/liballoc/collections/btree/map.rs
@@ -675,13 +675,15 @@ impl<K: Ord, V> BTreeMap<K, V> {
         T: Ord,
         K: Borrow<T>,
     {
-        match self.length {
-            0 => None,
-            _ => Some(OccupiedEntry {
-                handle: self.root.as_mut().first_kv(),
+        let front = self.root.as_mut().first_leaf_edge();
+        if let Ok(kv) = front.right_kv() {
+            Some(OccupiedEntry {
+                handle: kv.forget_node_type(),
                 length: &mut self.length,
                 _marker: PhantomData,
-            }),
+            })
+        } else {
+            None
         }
     }
 
@@ -736,13 +738,15 @@ impl<K: Ord, V> BTreeMap<K, V> {
         T: Ord,
         K: Borrow<T>,
     {
-        match self.length {
-            0 => None,
-            _ => Some(OccupiedEntry {
-                handle: self.root.as_mut().last_kv(),
+        let back = self.root.as_mut().last_leaf_edge();
+        if let Ok(kv) = back.left_kv() {
+            Some(OccupiedEntry {
+                handle: kv.forget_node_type(),
                 length: &mut self.length,
                 _marker: PhantomData,
-            }),
+            })
+        } else {
+            None
         }
     }
 
-- 
cgit 1.4.1-3-g733a5