diff --git a/Lib/ruby/rubymacros.swg b/Lib/ruby/rubymacros.swg
index 4fd0d1f90..54959c202 100644
--- a/Lib/ruby/rubymacros.swg
+++ b/Lib/ruby/rubymacros.swg
@@ -1 +1,11 @@
+
+// Redefine these macros so argument index for ruby is done properly,
+// ignoring self.
+#define %argfail_fmt(_type,_name,_argn) \
+ Ruby_Format_TypeError( "", _type, #_name, _argn )
+
+#define %argnullref_fmt(_type,_name,_argn) \
+ Ruby_Format_TypeError(%nullref_fmt(), _type, #_name, _argn)
+
+
 %include <typemaps/swigmacros.swg>