Remove Debug constraint on SumTree (and its related traits/structs) (#18248)

Release Notes:

- N/A

Co-authored-by: Nathan <nathan@zed.dev>

crates/sum_tree/src/sum_tree.rs

@@ -34,7 +34,7 @@ pub trait KeyedItem: Item {
 ///
 /// Each Summary type can have multiple [`Dimensions`] that it measures,
 /// which can be used to navigate the tree
-pub trait Summary: Clone + fmt::Debug {
+pub trait Summary: Clone {
     type Context;
 
     fn zero(cx: &Self::Context) -> Self;
@@ -49,7 +49,7 @@ pub trait Summary: Clone + fmt::Debug {
 /// # Example:
 /// Zed's rope has a `TextSummary` type that summarizes lines, characters, and bytes.
 /// Each of these are different dimensions we may want to seek to
-pub trait Dimension<'a, S: Summary>: Clone + fmt::Debug {
+pub trait Dimension<'a, S: Summary>: Clone {
     fn zero(cx: &S::Context) -> Self;
 
     fn add_summary(&mut self, summary: &'a S, cx: &S::Context);
@@ -71,7 +71,7 @@ impl<'a, T: Summary> Dimension<'a, T> for T {
     }
 }
 
-pub trait SeekTarget<'a, S: Summary, D: Dimension<'a, S>>: fmt::Debug {
+pub trait SeekTarget<'a, S: Summary, D: Dimension<'a, S>> {
     fn cmp(&self, cursor_location: &D, cx: &S::Context) -> Ordering;
 }
 
@@ -173,9 +173,19 @@ impl Bias {
 /// The maximum number of items per node is `TREE_BASE * 2`.
 ///
 /// Any [`Dimension`] supported by the [`Summary`] type can be used to seek to a specific location in the tree.
-#[derive(Debug, Clone)]
+#[derive(Clone)]
 pub struct SumTree<T: Item>(Arc<Node<T>>);
 
+impl<T> fmt::Debug for SumTree<T>
+where
+    T: fmt::Debug + Item,
+    T::Summary: fmt::Debug,
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_tuple("SumTree").field(&self.0).finish()
+    }
+}
+
 impl<T: Item> SumTree<T> {
     pub fn new(cx: &<T::Summary as Summary>::Context) -> Self {
         SumTree(Arc::new(Node::Leaf {
@@ -763,7 +773,7 @@ where
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone)]
 pub enum Node<T: Item> {
     Internal {
         height: u8,
@@ -778,6 +788,39 @@ pub enum Node<T: Item> {
     },
 }
 
+impl<T> fmt::Debug for Node<T>
+where
+    T: Item + fmt::Debug,
+    T::Summary: fmt::Debug,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Node::Internal {
+                height,
+                summary,
+                child_summaries,
+                child_trees,
+            } => f
+                .debug_struct("Internal")
+                .field("height", height)
+                .field("summary", summary)
+                .field("child_summaries", child_summaries)
+                .field("child_trees", child_trees)
+                .finish(),
+            Node::Leaf {
+                summary,
+                items,
+                item_summaries,
+            } => f
+                .debug_struct("Leaf")
+                .field("summary", summary)
+                .field("items", items)
+                .field("item_summaries", item_summaries)
+                .finish(),
+        }
+    }
+}
+
 impl<T: Item> Node<T> {
     fn is_leaf(&self) -> bool {
         matches!(self, Node::Leaf { .. })