diff --git a/platform/util/src/com/intellij/util/diff/DiffTree.java b/platform/util/src/com/intellij/util/diff/DiffTree.java
index b8614b8e8771..c28e9c1db2dc 100644
--- a/platform/util/src/com/intellij/util/diff/DiffTree.java
+++ b/platform/util/src/com/intellij/util/diff/DiffTree.java
@@ -92,6 +92,10 @@ public class DiffTree<OT, NT> {
 
   @NotNull
   private CompareResult build(@NotNull OT oldNode, @NotNull NT newNode, int level, @NotNull DiffTreeChangeBuilder<OT, NT> consumer) {
+    if (level > 1000) {
+      return CompareResult.NOT_EQUAL;
+    }
+
     if (level == myNewChildrenLists.size()) {
       myNewChildrenLists.add(new Ref<NT[]>());
       myOldChildrenLists.add(new Ref<OT[]>());