diff --git a/platform/core-impl/src/com/intellij/psi/impl/source/tree/AstPath.java b/platform/core-impl/src/com/intellij/psi/impl/source/tree/AstPath.java
index 815f873e8a70..63219f353a62 100644
--- a/platform/core-impl/src/com/intellij/psi/impl/source/tree/AstPath.java
+++ b/platform/core-impl/src/com/intellij/psi/impl/source/tree/AstPath.java
@@ -133,7 +133,7 @@ public abstract class AstPath extends SubstrateRef {
       CompositeElement parentNode = myParent.getNode();
       parentNode.getFirstChildNode(); // expand chameleons, populate PATH_CHILDREN array
       CompositeElement[] children = parentNode.getUserData(PATH_CHILDREN);
-      assert children != null;
+      assert children != null : parentNode + " of " + parentNode.getClass();
       return children[myIndex];
     }