diff --git a/inst/include/stan/io/json/rapidjson_parser.hpp b/inst/include/stan/io/json/rapidjson_parser.hpp
index 7341b3d..98a43f1 100644
--- a/inst/include/stan/io/json/rapidjson_parser.hpp
+++ b/inst/include/stan/io/json/rapidjson_parser.hpp
@@ -109,13 +109,17 @@ struct RapidJSONHandler {
  */
 template <typename Handler>
 void rapidjson_parse(std::istream &in, Handler &handler) {
+  Rcpp::Rcout << "f421" << std::endl;
   rapidjson::Reader reader;
   RapidJSONHandler<Handler> filter(handler);
   rapidjson::IStreamWrapper isw(in);
+  Rcpp::Rcout << "f422" << std::endl;
   handler.start_text();
+  Rcpp::Rcout << "f423" << std::endl;
   if (!reader.Parse<rapidjson::kParseNanAndInfFlag
                     | rapidjson::kParseValidateEncodingFlag
                     | rapidjson::kParseFullPrecisionFlag>(isw, filter)) {
+  Rcpp::Rcout << "f424" << std::endl;
     rapidjson::ParseErrorCode err = reader.GetParseErrorCode();
     std::stringstream ss;
     ss << "Error in JSON parsing " << std::endl
@@ -127,6 +131,7 @@ void rapidjson_parse(std::istream &in, Handler &handler) {
     }
     throw json_error(ss.str());
   }
+  Rcpp::Rcout << "f425" << std::endl;
   handler.end_text();
 }
 }  // namespace json