diff --git a/platform/lang-impl/src/com/intellij/psi/impl/source/PsiFileImpl.java b/platform/lang-impl/src/com/intellij/psi/impl/source/PsiFileImpl.java
index c139c4157a18..29a406621db0 100644
--- a/platform/lang-impl/src/com/intellij/psi/impl/source/PsiFileImpl.java
+++ b/platform/lang-impl/src/com/intellij/psi/impl/source/PsiFileImpl.java
@@ -262,7 +262,8 @@ public abstract class PsiFileImpl extends ElementBase implements PsiFileEx, PsiF
   private void switchFromStubToAST(ASTNode root, final Iterator<StubElement<?>> stubs) {
     final IElementType contentElementType = getContentElementType();
     if (!(contentElementType instanceof IStubFileElementType)) {
-      throw new AssertionError("Invalid content element type: " + contentElementType + "; elementType=" + myElementType + "; file=" + getClass() + "; viewProvider=" + getViewProvider());
+      throw new AssertionError("Invalid content element type: " + contentElementType + " of " + contentElementType.getLanguage() +
+                               "; elementType=" + myElementType + " of " + myElementType.getLanguage() + "; file=" + getClass() + "; viewProvider=" + getViewProvider());
     }
     ((TreeElement)root).acceptTree(new RecursiveTreeElementWalkingVisitor() {
       final StubBuilder builder = ((IStubFileElementType)contentElementType).getBuilder();