From f33f266a8a20594736b8eb7c95a4d42478bec7cb Mon Sep 17 00:00:00 2001
From: Gary Guo <gary@garyguo.net>
Date: Sun, 15 Aug 2021 01:35:03 +0100
Subject: BTree: remove Ord bound from new

---
 library/alloc/src/collections/btree/map.rs       | 13 ++++---------
 library/alloc/src/collections/btree/map/tests.rs |  8 +++++++-
 library/alloc/src/collections/btree/set.rs       |  7 ++-----
 library/alloc/src/collections/btree/set/tests.rs |  8 +++++++-
 4 files changed, 20 insertions(+), 16 deletions(-)

(limited to 'library/alloc/src')

diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs
index 4b649e43371..70a838a35f9 100644
--- a/library/alloc/src/collections/btree/map.rs
+++ b/library/alloc/src/collections/btree/map.rs
@@ -233,9 +233,7 @@ impl<K: Clone, V: Clone> Clone for BTreeMap<K, V> {
         }
 
         if self.is_empty() {
-            // Ideally we'd call `BTreeMap::new` here, but that has the `K:
-            // Ord` constraint, which this method lacks.
-            BTreeMap { root: None, length: 0 }
+            BTreeMap::new()
         } else {
             clone_subtree(self.root.as_ref().unwrap().reborrow()) // unwrap succeeds because not empty
         }
@@ -499,10 +497,7 @@ impl<K, V> BTreeMap<K, V> {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
-    pub const fn new() -> BTreeMap<K, V>
-    where
-        K: Ord,
-    {
+    pub const fn new() -> BTreeMap<K, V> {
         BTreeMap { root: None, length: 0 }
     }
 
@@ -522,7 +517,7 @@ impl<K, V> BTreeMap<K, V> {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn clear(&mut self) {
-        *self = BTreeMap { root: None, length: 0 };
+        *self = BTreeMap::new();
     }
 
     /// Returns a reference to the value corresponding to the key.
@@ -1957,7 +1952,7 @@ impl<K: Hash, V: Hash> Hash for BTreeMap<K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<K: Ord, V> Default for BTreeMap<K, V> {
+impl<K, V> Default for BTreeMap<K, V> {
     /// Creates an empty `BTreeMap`.
     fn default() -> BTreeMap<K, V> {
         BTreeMap::new()
diff --git a/library/alloc/src/collections/btree/map/tests.rs b/library/alloc/src/collections/btree/map/tests.rs
index 17e53848343..a99d6c49ab7 100644
--- a/library/alloc/src/collections/btree/map/tests.rs
+++ b/library/alloc/src/collections/btree/map/tests.rs
@@ -1745,7 +1745,7 @@ fn test_send() {
     }
 }
 
-#[allow(dead_code)]
+#[test]
 fn test_ord_absence() {
     fn map<K>(mut map: BTreeMap<K, ()>) {
         map.is_empty();
@@ -1784,6 +1784,12 @@ fn test_ord_absence() {
     fn map_clone<K: Clone>(mut map: BTreeMap<K, ()>) {
         map.clone_from(&map.clone());
     }
+
+    #[derive(Debug, Clone)]
+    struct NonOrd;
+    map(BTreeMap::<NonOrd, _>::new());
+    map_debug(BTreeMap::<NonOrd, _>::new());
+    map_clone(BTreeMap::<NonOrd, _>::default());
 }
 
 #[test]
diff --git a/library/alloc/src/collections/btree/set.rs b/library/alloc/src/collections/btree/set.rs
index 0c268ad32b2..ff0db22e0cc 100644
--- a/library/alloc/src/collections/btree/set.rs
+++ b/library/alloc/src/collections/btree/set.rs
@@ -246,10 +246,7 @@ impl<T> BTreeSet<T> {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
-    pub const fn new() -> BTreeSet<T>
-    where
-        T: Ord,
-    {
+    pub const fn new() -> BTreeSet<T> {
         BTreeSet { map: BTreeMap::new() }
     }
 
@@ -1192,7 +1189,7 @@ impl<'a, T: 'a + Ord + Copy> Extend<&'a T> for BTreeSet<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Ord> Default for BTreeSet<T> {
+impl<T> Default for BTreeSet<T> {
     /// Creates an empty `BTreeSet`.
     fn default() -> BTreeSet<T> {
         BTreeSet::new()
diff --git a/library/alloc/src/collections/btree/set/tests.rs b/library/alloc/src/collections/btree/set/tests.rs
index 5d590a26281..0a87ae12d61 100644
--- a/library/alloc/src/collections/btree/set/tests.rs
+++ b/library/alloc/src/collections/btree/set/tests.rs
@@ -607,7 +607,7 @@ fn test_send() {
     }
 }
 
-#[allow(dead_code)]
+#[test]
 fn test_ord_absence() {
     fn set<K>(mut set: BTreeSet<K>) {
         set.is_empty();
@@ -626,6 +626,12 @@ fn test_ord_absence() {
     fn set_clone<K: Clone>(mut set: BTreeSet<K>) {
         set.clone_from(&set.clone());
     }
+
+    #[derive(Debug, Clone)]
+    struct NonOrd;
+    set(BTreeSet::<NonOrd>::new());
+    set_debug(BTreeSet::<NonOrd>::new());
+    set_clone(BTreeSet::<NonOrd>::default());
 }
 
 #[test]
-- 
cgit 1.4.1-3-g733a5