diff --git a/frontend/json/jsonparse.cc b/frontend/json/jsonparse.cc
index 45edabad..0f8fb48c 100644
--- a/frontend/json/jsonparse.cc
+++ b/frontend/json/jsonparse.cc
@@ -377,7 +377,7 @@ void	json_import_cell_ports(Design *design, string &modname, CellInfo *cell,
 		log_error("JSON no connection match "
 			"for port_direction \'%s\' of node \'%s\' "
 				"in module \'%s\'\n",
-			port_name, cell->name.c_str(), modname.c_str());
+			port_name.c_str(), cell->name.c_str(), modname.c_str());
 
 	assert(wire_group_node);
 
@@ -546,7 +546,7 @@ void	json_import_cell(Design *design, string modname, JsonNode *cell_node,
 
 	param_node = cell_node->data_dict.at("parameters");
 	if (param_node->type != 'D')
-		log_error("JSON parameter list of \'%s\' is not a data dictionary\n", cell->name);
+		log_error("JSON parameter list of \'%s\' is not a data dictionary\n", cell->name.c_str());
 
 	//
 	// Loop through all parameters, adding them into the
diff --git a/frontend/json/jsonparse.h b/frontend/json/jsonparse.h
index 12bf6dcd..6b444be9 100644
--- a/frontend/json/jsonparse.h
+++ b/frontend/json/jsonparse.h
@@ -24,6 +24,6 @@
 #include <istream>
 #include "design.h"
 
-extern	void	parse_json_file(std::istream *&, std::string &, Design *);
+extern	void	parse_json_file(std::istream *&, std::string , Design *);
 
 #endif