diff --git a/platform/core-impl/src/com/intellij/psi/impl/source/tree/CompositeElement.java b/platform/core-impl/src/com/intellij/psi/impl/source/tree/CompositeElement.java
index f03379c26079..3ca0cd091083 100644
--- a/platform/core-impl/src/com/intellij/psi/impl/source/tree/CompositeElement.java
+++ b/platform/core-impl/src/com/intellij/psi/impl/source/tree/CompositeElement.java
@@ -281,7 +281,7 @@ public class CompositeElement extends TreeElement {
     }
     if (endOffset != len) {
       @NonNls String msg = "len=" + len + ";\n endOffset=" + endOffset;
-      msg += diagnoseTextInconsistency(new String(buffer, 0, endOffset), startStamp);
+      msg += diagnoseTextInconsistency(new String(buffer, 0, Math.min(len, endOffset)), startStamp);
       throw new AssertionError(msg);
     }
     return buffer;