BTree: remove Ord bound where it is absent elsewhere

library/alloc/src/collections/btree/map.rs

@@ -501,11 +501,8 @@ impl<K, V> BTreeMap<K, V> {
     /// assert!(a.is_empty());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn clear(&mut self)
-    where
-        K: Ord,
-    {
-        *self = BTreeMap::new();
+    pub fn clear(&mut self) {
+        *self = BTreeMap { root: None, length: 0 };
     }
 
     /// Returns a reference to the value corresponding to the key.
@@ -1226,10 +1223,7 @@ impl<K, V> BTreeMap<K, V> {
     /// ```
     #[inline]
     #[unstable(feature = "map_into_keys_values", issue = "75294")]
-    pub fn into_keys(self) -> IntoKeys<K, V>
-    where
-        K: Ord,
-    {
+    pub fn into_keys(self) -> IntoKeys<K, V> {
         IntoKeys { inner: self.into_iter() }
     }
 
@@ -1252,10 +1246,7 @@ impl<K, V> BTreeMap<K, V> {
     /// ```
     #[inline]
     #[unstable(feature = "map_into_keys_values", issue = "75294")]
-    pub fn into_values(self) -> IntoValues<K, V>
-    where
-        K: Ord,
-    {
+    pub fn into_values(self) -> IntoValues<K, V> {
         IntoValues { inner: self.into_iter() }
     }
 }

library/alloc/src/collections/btree/map/tests.rs

@@ -1711,12 +1711,19 @@ fn test_ord_absence() {
     fn map<K>(mut map: BTreeMap<K, ()>) {
         map.is_empty();
         map.len();
+        map.clear();
         map.iter();
         map.iter_mut();
         map.keys();
         map.values();
         map.values_mut();
-        map.into_iter();
+        if true {
+            map.into_values();
+        } else if true {
+            map.into_iter();
+        } else {
+            map.into_keys();
+        }
     }
 
     fn map_debug<K: Debug>(mut map: BTreeMap<K, ()>) {
@@ -1726,7 +1733,13 @@ fn test_ord_absence() {
         format!("{:?}", map.keys());
         format!("{:?}", map.values());
         format!("{:?}", map.values_mut());
-        format!("{:?}", map.into_iter());
+        if true {
+            format!("{:?}", map.into_iter());
+        } else if true {
+            format!("{:?}", map.into_keys());
+        } else {
+            format!("{:?}", map.into_values());
+        }
     }
 
     fn map_clone<K: Clone>(mut map: BTreeMap<K, ()>) {

library/alloc/src/collections/btree/set.rs

@@ -457,10 +457,7 @@ impl<T> BTreeSet<T> {
     /// assert!(v.is_empty());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn clear(&mut self)
-    where
-        T: Ord,
-    {
+    pub fn clear(&mut self) {
         self.map.clear()
     }
 

library/alloc/src/collections/btree/set/tests.rs

@@ -641,9 +641,10 @@ fn test_send() {
 
 #[allow(dead_code)]
 fn test_ord_absence() {
-    fn set<K>(set: BTreeSet<K>) {
+    fn set<K>(mut set: BTreeSet<K>) {
         set.is_empty();
         set.len();
+        set.clear();
         set.iter();
         set.into_iter();
     }