protected @NotNull FileElement createFileElement(CharSequence docText) {
    FileElement treeElement;
    TreeElement contentLeaf = createContentLeafElement(docText);

    if (contentLeaf instanceof FileElement) {
      treeElement = (FileElement)contentLeaf;
    }
    else {
      CompositeElement xxx = ASTFactory.composite(myElementType);
      assert xxx instanceof FileElement : "BUMM";
      treeElement = (FileElement)xxx;
      treeElement.rawAddChildrenWithoutNotifications(contentLeaf);
    }

    return treeElement;
  }
protected @NotNull FileElement createFileElement(CharSequence docText)