anchor.diff:  
     bool visitClassDeclaration(ast.ClassDeclaration node) {
       node.members.forEach(visit);
  +    return false;
  +  }
  +
  +  bool visitConstructorDeclaration(ast.ConstructorDeclaration node) {
       return false;
     }
   
  
positive.code:   bool visitExpressionFunctionBody(ast.ExpressionFunctionBody node) {
      if (node.keyword == null) return false;
      return visit(node.expression);
    }
  
    bool visitArgumentList(ast.ArgumentList node) {
  
negative.code:         node.rightBracket);
    }
  
    visitConstructorDeclaration(ast.ConstructorDeclaration node) {
      return node;
    }
  
    visitFieldDeclaration(ast.FieldDeclaration node) {
      return node;
    }
  
    visitMethodDeclaration(ast.MethodDeclaration node) {
      node.body = visit(node.body);
      return node;
    }
  
    visitTopLevelVariableDeclaration(ast.TopLevelVariableDeclaration node) {
      return node;
    }
  
  