anchor.diff:      throw UnimplementedError('${node.runtimeType}');
     }
   
  -  bool isMethod(LinkedNode node) {
  -    return node.kind == LinkedNodeKind.methodDeclaration;
  -  }
  -
     bool isSetter(AstNode node) {
       if (node is FunctionDeclaration) {
         return node.isSetter;
  
positive.code:     }
    }
  
    InterfaceType getInterfaceType(LinkedNodeType linkedType) {
      var type = readType(linkedType);
      if (type is InterfaceType && !type.element.isEnum) {
        return type;
      }
      return null;
    }
  
    Comment getLibraryDocumentationComment(CompilationUnit unit) {
      for (var directive in unit.directives) {
        if (directive is LibraryDirective) {
  
negative.code: 
    String getSelectedUri(UriBasedDirective node) {
      return LazyDirective.getSelectedUri(node);
    }
  
    TypeName getSuperclass(AstNode node) {
  