Index: TODO
===================================================================
diff -u -re415f4153e7750b77616795150822b91db1ba9d4 -r507acdb9edb4f73339590c097aee004401cedc45
--- TODO	(.../TODO)	(revision e415f4153e7750b77616795150822b91db1ba9d4)
+++ TODO	(.../TODO)	(revision 507acdb9edb4f73339590c097aee004401cedc45)
@@ -2044,6 +2044,8 @@
 - added returns handling for nx in serializer
 - extended regression test
 
+- provide warning if nonpositional argument is passed more than once
+
 TODO:
 
 - check performance implications of value conflict checker
Index: generic/nsf.c
===================================================================
diff -u -rbb18837f55b64ecdaf970c9e77624bc30f4c417a -r507acdb9edb4f73339590c097aee004401cedc45
--- generic/nsf.c	(.../nsf.c)	(revision bb18837f55b64ecdaf970c9e77624bc30f4c417a)
+++ generic/nsf.c	(.../nsf.c)	(revision 507acdb9edb4f73339590c097aee004401cedc45)
@@ -11957,6 +11957,12 @@
                     return TCL_ERROR;
                   }
 
+		  if (pcPtr->flags[j] & NSF_ARG_SET) {
+		    NsfLog(interp, NSF_LOG_WARN, "Non-positional parameter %s was passed more than once",
+			   nppPtr->name);
+		  }
+		  pcPtr->flags[j] |= NSF_ARG_SET;
+
                   if (pcPtr->flags[j] & NSF_PC_MUST_DECR) {
 		    pcPtr->status |= NSF_PC_STATUS_MUST_DECR;
 		  }
Index: generic/nsfInt.h
===================================================================
diff -u -ra82b93b0eb26ab0e3e815ffc229bd61b7d5ef2cc -r507acdb9edb4f73339590c097aee004401cedc45
--- generic/nsfInt.h	(.../nsfInt.h)	(revision a82b93b0eb26ab0e3e815ffc229bd61b7d5ef2cc)
+++ generic/nsfInt.h	(.../nsfInt.h)	(revision 507acdb9edb4f73339590c097aee004401cedc45)
@@ -375,6 +375,7 @@
 #define NSF_ARG_IS_CONVERTER		0x2000
 #define NSF_ARG_IS_ENUMERATION		0x4000
 #define NSF_ARG_CHECK_NONPOS		0x8000
+#define NSF_ARG_SET		       0x10000
 
 /* Disallowed parameter options */
 #define NSF_DISALLOWED_ARG_METHOD_PARAMETER	     (NSF_ARG_METHOD|NSF_ARG_INITCMD|NSF_ARG_RELATION)