diff --git a/lib/src/default_index_store.rs b/lib/src/default_index_store.rs
index 4e5db7cac..29297256d 100644
--- a/lib/src/default_index_store.rs
+++ b/lib/src/default_index_store.rs
@@ -679,6 +679,10 @@ impl MutableIndexImpl {
     pub fn stats(&self) -> IndexStats {
         CompositeIndex(self).stats()
     }
+
+    pub fn num_commits(&self) -> u32 {
+        CompositeIndex(self).num_commits()
+    }
 }
 
 impl Index for MutableIndexImpl {
@@ -686,10 +690,6 @@ impl Index for MutableIndexImpl {
         self
     }
 
-    fn num_commits(&self) -> u32 {
-        CompositeIndex(self).num_commits()
-    }
-
     fn commit_id_to_pos(&self, commit_id: &CommitId) -> Option<IndexPosition> {
         CompositeIndex(self).commit_id_to_pos(commit_id)
     }
@@ -1752,6 +1752,10 @@ impl ReadonlyIndexImpl {
     pub fn stats(&self) -> IndexStats {
         CompositeIndex(self).stats()
     }
+
+    pub fn num_commits(&self) -> u32 {
+        CompositeIndex(self).num_commits()
+    }
 }
 
 impl Index for ReadonlyIndexImpl {
@@ -1759,10 +1763,6 @@ impl Index for ReadonlyIndexImpl {
         self
     }
 
-    fn num_commits(&self) -> u32 {
-        CompositeIndex(self).num_commits()
-    }
-
     fn commit_id_to_pos(&self, commit_id: &CommitId) -> Option<IndexPosition> {
         CompositeIndex(self).commit_id_to_pos(commit_id)
     }
diff --git a/lib/src/index.rs b/lib/src/index.rs
index dc1ad91d7..ce6fb0c58 100644
--- a/lib/src/index.rs
+++ b/lib/src/index.rs
@@ -48,8 +48,6 @@ pub trait IndexStore: Send + Sync + Debug {
 pub trait Index {
     fn as_any(&self) -> &dyn Any;
 
-    fn num_commits(&self) -> u32;
-
     fn commit_id_to_pos(&self, commit_id: &CommitId) -> Option<IndexPosition>;
 
     fn shortest_unique_commit_id_prefix_len(&self, commit_id: &CommitId) -> usize;