diff --git a/src/language/PEGGrammar.hpp b/src/language/PEGGrammar.hpp
index bac0eb913f101c2b0f55c9aaa37582b9a5e03100..6e095fcbec0164635e510b9f5dbaeac88006ced3 100644
--- a/src/language/PEGGrammar.hpp
+++ b/src/language/PEGGrammar.hpp
@@ -299,7 +299,7 @@ struct errors : public normal<Rule>
 };
 
 template <typename Rule>
-inline const std::string errors<Rule>::error_message = "parse error matching "+ std::string{internal::demangle< Rule >()};
+inline const std::string errors<Rule>::error_message = "parse error matching "+ demangle(internal::demangle< Rule >());
 
 template <>
 inline const std::string errors<language::module_name>::error_message = "parse error, missing module name";