diff --git a/source/function.hpp b/source/function.hpp
index 4e3a320f..15bae4af 100644
--- a/source/function.hpp
+++ b/source/function.hpp
@@ -14,6 +14,7 @@
 #define _INCLUDED_function_hpp_
 
 #include <binder.hpp>
+#include <config.hpp>
 
 #include <clang/AST/Decl.h>
 #include <clang/AST/DeclCXX.h>