1 files changed, 13 insertions, 29 deletions

diff --git a/src/mutable_keys.rs b/src/mutable_keys.rs
index 7efc779..35a90c4 100644
--- a/src/mutable_keys.rs
+++ b/src/mutable_keys.rs
@@ -1,6 +1,8 @@
 use core::hash::{BuildHasher, Hash};
 
-use super::{Bucket, Entries, Equivalent, IndexMap};
+use super::{Equivalent, IndexMap};
+
+pub struct PrivateMarker {}
 
 /// Opt-in mutable access to keys.
 ///
@@ -14,15 +16,11 @@ use super::{Bucket, Entries, Equivalent, IndexMap};
 /// implementing PartialEq, Eq, or Hash incorrectly would be).
 ///
 /// `use` this trait to enable its methods for `IndexMap`.
-///
-/// This trait is sealed and cannot be implemented for types outside this crate.
-pub trait MutableKeys: private::Sealed {
+pub trait MutableKeys {
     type Key;
     type Value;
 
     /// Return item index, mutable reference to key and value
-    ///
-    /// Computes in **O(1)** time (average).
     fn get_full_mut2<Q: ?Sized>(
         &mut self,
         key: &Q,
@@ -30,13 +28,6 @@ pub trait MutableKeys: private::Sealed {
     where
         Q: Hash + Equivalent<Self::Key>;
 
-    /// Return mutable reference to key and value at an index.
-    ///
-    /// Valid indices are *0 <= index < self.len()*
-    ///
-    /// Computes in **O(1)** time.
-    fn get_index_mut2(&mut self, index: usize) -> Option<(&mut Self::Key, &mut Self::Value)>;
-
     /// Scan through each key-value pair in the map and keep those where the
     /// closure `keep` returns `true`.
     ///
@@ -47,6 +38,11 @@ pub trait MutableKeys: private::Sealed {
     fn retain2<F>(&mut self, keep: F)
     where
         F: FnMut(&mut Self::Key, &mut Self::Value) -> bool;
+
+    /// This method is not useful in itself – it is there to “seal” the trait
+    /// for external implementation, so that we can add methods without
+    /// causing breaking changes.
+    fn __private_marker(&self) -> PrivateMarker;
 }
 
 /// Opt-in mutable access to keys.
@@ -59,21 +55,11 @@ where
 {
     type Key = K;
     type Value = V;
-
     fn get_full_mut2<Q: ?Sized>(&mut self, key: &Q) -> Option<(usize, &mut K, &mut V)>
     where
         Q: Hash + Equivalent<K>,
     {
-        if let Some(i) = self.get_index_of(key) {
-            let entry = &mut self.as_entries_mut()[i];
-            Some((i, &mut entry.key, &mut entry.value))
-        } else {
-            None
-        }
-    }
-
-    fn get_index_mut2(&mut self, index: usize) -> Option<(&mut K, &mut V)> {
-        self.as_entries_mut().get_mut(index).map(Bucket::muts)
+        self.get_full_mut2_impl(key)
     }
 
     fn retain2<F>(&mut self, keep: F)
@@ -82,10 +68,8 @@ where
     {
         self.retain_mut(keep)
     }
-}
-
-mod private {
-    pub trait Sealed {}
 
-    impl<K, V, S> Sealed for super::IndexMap<K, V, S> {}
+    fn __private_marker(&self) -> PrivateMarker {
+        PrivateMarker {}
+    }
 }