diff --git a/zed/src/editor/buffer/mod.rs b/zed/src/editor/buffer/mod.rs
index 9a35a61de3..bb796ace93 100644
--- a/zed/src/editor/buffer/mod.rs
+++ b/zed/src/editor/buffer/mod.rs
@@ -2105,7 +2105,7 @@ impl sum_tree::Item for Fragment {
 impl sum_tree::Summary for FragmentSummary {
     type Context = ();
 
-    fn add_summary(&mut self, other: &Self) {
+    fn add_summary(&mut self, other: &Self, _: Option<&Self::Context>) {
         self.text_summary += &other.text_summary;
         debug_assert!(self.max_fragment_id <= other.max_fragment_id);
         self.max_fragment_id = other.max_fragment_id.clone();
@@ -2171,7 +2171,7 @@ impl sum_tree::Item for InsertionSplit {
 impl sum_tree::Summary for InsertionSplitSummary {
     type Context = ();
 
-    fn add_summary(&mut self, other: &Self) {
+    fn add_summary(&mut self, other: &Self, _: Option<&Self::Context>) {
         self.extent += other.extent;
     }
 }
diff --git a/zed/src/editor/buffer/text.rs b/zed/src/editor/buffer/text.rs
index 02f584a395..140fe2257e 100644
--- a/zed/src/editor/buffer/text.rs
+++ b/zed/src/editor/buffer/text.rs
@@ -61,7 +61,7 @@ pub struct TextSummary {
 impl sum_tree::Summary for TextSummary {
     type Context = ();
 
-    fn add_summary(&mut self, other: &Self) {
+    fn add_summary(&mut self, other: &Self, _: Option<&Self::Context>) {
         *self += other;
     }
 }
diff --git a/zed/src/editor/display_map/fold_map.rs b/zed/src/editor/display_map/fold_map.rs
index 21d033ce64..c2892fa1d3 100644
--- a/zed/src/editor/display_map/fold_map.rs
+++ b/zed/src/editor/display_map/fold_map.rs
@@ -459,7 +459,7 @@ impl sum_tree::Item for Transform {
 impl sum_tree::Summary for TransformSummary {
     type Context = ();
 
-    fn add_summary(&mut self, other: &Self) {
+    fn add_summary(&mut self, other: &Self, _: Option<&Self::Context>) {
         self.buffer += &other.buffer;
         self.display += &other.display;
     }
@@ -467,7 +467,7 @@ impl sum_tree::Summary for TransformSummary {
 
 impl<'a> sum_tree::Dimension<'a, TransformSummary> for TransformSummary {
     fn add_summary(&mut self, summary: &'a TransformSummary) {
-        sum_tree::Summary::add_summary(self, summary);
+        sum_tree::Summary::add_summary(self, summary, None);
     }
 }
 
@@ -512,7 +512,7 @@ impl Default for FoldSummary {
 impl sum_tree::Summary for FoldSummary {
     type Context = Buffer;
 
-    fn add_summary_with_ctx(&mut self, other: &Self, buffer: Option<&Self::Context>) {
+    fn add_summary(&mut self, other: &Self, buffer: Option<&Self::Context>) {
         let buffer = buffer.unwrap();
         if other.min_start.cmp(&self.min_start, buffer).unwrap() == Ordering::Less {
             self.min_start = other.min_start.clone();
diff --git a/zed/src/operation_queue.rs b/zed/src/operation_queue.rs
index 27b0550b76..e70d91b6cb 100644
--- a/zed/src/operation_queue.rs
+++ b/zed/src/operation_queue.rs
@@ -68,7 +68,7 @@ impl<T: Operation> KeyedItem for T {
 impl Summary for OperationSummary {
     type Context = ();
 
-    fn add_summary(&mut self, other: &Self) {
+    fn add_summary(&mut self, other: &Self, _: Option<&Self::Context>) {
         assert!(self.key < other.key);
         self.key = other.key;
         self.len += other.len;
diff --git a/zed/src/sum_tree/cursor.rs b/zed/src/sum_tree/cursor.rs
index 44647ceb37..d90702ab6e 100644
--- a/zed/src/sum_tree/cursor.rs
+++ b/zed/src/sum_tree/cursor.rs
@@ -560,7 +560,7 @@ where
                                             slice_items_summary
                                                 .as_mut()
                                                 .unwrap()
-                                                .add_summary_with_ctx(item_summary, ctx);
+                                                .add_summary(item_summary, ctx);
                                         }
                                         SeekAggregate::Summary(summary) => {
                                             summary.add_summary(item_summary);
@@ -679,7 +679,7 @@ where
                                         slice_items_summary
                                             .as_mut()
                                             .unwrap()
-                                            .add_summary_with_ctx(item_summary, ctx);
+                                            .add_summary(item_summary, ctx);
                                         slice_item_summaries.push(item_summary.clone());
                                     }
                                     SeekAggregate::Summary(summary) => {
diff --git a/zed/src/sum_tree/mod.rs b/zed/src/sum_tree/mod.rs
index 0c85eaa8ef..375e2d7e2a 100644
--- a/zed/src/sum_tree/mod.rs
+++ b/zed/src/sum_tree/mod.rs
@@ -25,14 +25,7 @@ pub trait KeyedItem: Item {
 pub trait Summary: Default + Clone + fmt::Debug {
     type Context;
 
-    fn add_summary(&mut self, _summary: &Self) {
-        unimplemented!();
-    }
-
-    fn add_summary_with_ctx(&mut self, summary: &Self, ctx: Option<&Self::Context>) {
-        assert!(ctx.is_none());
-        self.add_summary(summary);
-    }
+    fn add_summary(&mut self, summary: &Self, ctx: Option<&Self::Context>);
 }
 
 pub trait Dimension<'a, S: Summary>: Clone + fmt::Debug + Default {
@@ -134,6 +127,13 @@ impl<T: Item> SumTree<T> {
     }
 
     pub fn extend<I>(&mut self, iter: I)
+    where
+        I: IntoIterator<Item = T>,
+    {
+        self.extend_with_ctx(iter, None)
+    }
+
+    pub fn extend_with_ctx<I>(&mut self, iter: I, ctx: Option<&<T::Summary as Summary>::Context>)
     where
         I: IntoIterator<Item = T>,
     {
@@ -159,7 +159,7 @@ impl<T: Item> SumTree<T> {
             }) = leaf.as_mut()
             {
                 let item_summary = item.summary();
-                summary.add_summary(&item_summary);
+                summary.add_summary(&item_summary, ctx);
                 items.push(item);
                 item_summaries.push(item_summary);
             } else {
@@ -226,7 +226,7 @@ impl<T: Item> SumTree<T> {
                 ..
             } => {
                 let other_node = other.0.clone();
-                summary.add_summary_with_ctx(other_node.summary(), ctx);
+                summary.add_summary(other_node.summary(), ctx);
 
                 let height_delta = *height - other_node.height();
                 let mut summaries_to_append = ArrayVec::<[T::Summary; 2 * TREE_BASE]>::new();
@@ -323,7 +323,7 @@ impl<T: Item> SumTree<T> {
                         item_summaries: right_summaries,
                     })))
                 } else {
-                    summary.add_summary_with_ctx(other_node.summary(), ctx);
+                    summary.add_summary(other_node.summary(), ctx);
                     items.extend(other_node.items().iter().cloned());
                     item_summaries.extend(other_node.child_summaries().iter().cloned());
                     None
@@ -538,7 +538,7 @@ where
 {
     let mut sum = T::default();
     for value in iter {
-        sum.add_summary_with_ctx(value, ctx);
+        sum.add_summary(value, ctx);
     }
     sum
 }
@@ -889,7 +889,7 @@ mod tests {
     impl Summary for IntegersSummary {
         type Context = ();
 
-        fn add_summary(&mut self, other: &Self) {
+        fn add_summary(&mut self, other: &Self, _: Option<&Self::Context>) {
             self.count.0 += &other.count.0;
             self.sum.0 += &other.sum.0;
             self.contains_even |= other.contains_even;
diff --git a/zed/src/worktree.rs b/zed/src/worktree.rs
index eb5172d577..2c16833395 100644
--- a/zed/src/worktree.rs
+++ b/zed/src/worktree.rs
@@ -538,7 +538,7 @@ impl Default for EntrySummary {
 impl sum_tree::Summary for EntrySummary {
     type Context = ();
 
-    fn add_summary(&mut self, rhs: &Self) {
+    fn add_summary(&mut self, rhs: &Self, _: Option<&Self::Context>) {
         self.max_path = rhs.max_path.clone();
         self.file_count += rhs.file_count;
         self.visible_file_count += rhs.visible_file_count;