Index: generic/xotcl.c
===================================================================
diff -u -r147831f1098cb9b96a28d4d5b0f9f3ccea35b9da -r0e4d8c600ce1f742ffe04041b7db56bde53c20d6
--- generic/xotcl.c	(.../xotcl.c)	(revision 147831f1098cb9b96a28d4d5b0f9f3ccea35b9da)
+++ generic/xotcl.c	(.../xotcl.c)	(revision 0e4d8c600ce1f742ffe04041b7db56bde53c20d6)
@@ -6399,11 +6399,24 @@
   } else if (strncmp(option, "method", 6) == 0) {
     paramPtr->flags |= XOTCL_ARG_METHOD;
   } else if (strncmp(option, "multivalued", 11) == 0) {
+    if ((paramPtr->flags & (XOTCL_ARG_INITCMD|XOTCL_ARG_RELATION|XOTCL_ARG_METHOD|XOTCL_ARG_SWITCH)) != 0)
+      return XOTclVarErrMsg(interp, 
+                            "option multivalued not allowed for \"initcmd\", \"method\", \"relation\" or \"switch\"\n", 
+                            (char *) NULL);
     paramPtr->flags |= XOTCL_ARG_MULTIVALUED;
   } else if (strncmp(option, "noarg", 5) == 0) {
+    if ((paramPtr->flags & XOTCL_ARG_METHOD) == 0) {
+      return XOTclVarErrMsg(interp, "option noarg only allowed for parameter type \"method\"", 
+                            (char *) NULL);
+    }
     paramPtr->flags |= XOTCL_ARG_NOARG;
     paramPtr->nrArgs = 0;
   } else if (length >= 5 && strncmp(option, "arg=", 4) == 0) {
+    if ((paramPtr->flags & (XOTCL_ARG_METHOD|XOTCL_ARG_RELATION)) == 0
+        && paramPtr->converter != convertViaCmd)
+      return XOTclVarErrMsg(interp, 
+                            "option arg= only allowed for \"method\", \"relation\" or \"user-defined converter\"", 
+                            (char *) NULL);
     paramPtr->converterArg =  Tcl_NewStringObj(option+4, length-4);
     INCR_REF_COUNT(paramPtr->converterArg);
   } else if (strncmp(option, "switch", 6) == 0) {
Index: tests/parameters.xotcl
===================================================================
diff -u -r6392a9deba783dd17186ca2ba94c22f90267d79c -r0e4d8c600ce1f742ffe04041b7db56bde53c20d6
--- tests/parameters.xotcl	(.../parameters.xotcl)	(revision 6392a9deba783dd17186ca2ba94c22f90267d79c)
+++ tests/parameters.xotcl	(.../parameters.xotcl)	(revision 0e4d8c600ce1f742ffe04041b7db56bde53c20d6)
@@ -46,8 +46,8 @@
 #   noarg
 #   arg=
 #   substdefault:  if no value given, subst on default (result is substituted value); 
-#                  can use variable resolvers,
-#                  for scripted/c-methods/obj-parm, 
+#                  susbt cmd can use variable resolvers,
+#                  works for scripted/c-methods and obj-parm, 
 #                  autmatically set by  "$slot toParameterSyntax" if default contains "[" ... "]".
 #
 #   initcmd:       evaluate body in an xotcl nonleaf frame, called via configure 
@@ -56,20 +56,20 @@
 #                  specified value is the first argument unless "noarg" is used  
 #                  (example: -noinit).
 #
-# parameter type   multivalued  required  noarg  type=   arg=  valueCheck  methodParm   objectParm
-#  initcmd            NO         YES        NO    NO      NO      NO        NO/POSSIBLE    YES
-#  method             NO         YES        YES   NO      YES     NO        NO/POSSIBLE    YES
+# parameter type   multivalued  required  noarg  type=   arg=  valueCheck  methodParm  objectParm
+#  initcmd            NO         YES        NO    NO      NO      NO       NO/POSSIBLE    YES
+#  method             NO         YES        YES   NO      YES     NO       NO/POSSIBLE    YES
 #
-#  relation           NO         YES        NO    NO      YES     NO           NO          YES
-#  stringtype         YES        YES        NO    NO      NO      YES          YES         YES
+#  relation           NO         YES        NO    NO      YES     NO          NO          YES
+#  stringtype         YES        YES        NO    NO      NO      YES         YES         YES
 #
-#  switch             NO         NO         NO    NO      NO      NO           YES         YES
-#  integer            YES        YES        NO    NO      NO      YES          YES         YES    
-#  boolean            YES        YES        NO    NO      NO      YES          YES         YES
-#  object             YES        YES        NO    YES     NO      YES          YES         YES
-#  class              YES        YES        NO    YES     NO      YES          YES         YES
+#  switch             NO         NO         NO    NO      NO      NO          YES         YES
+#  integer            YES        YES        NO    NO      NO      YES         YES         YES    
+#  boolean            YES        YES        NO    NO      NO      YES         YES         YES
+#  object             YES        YES        NO    YES     NO      YES         YES         YES
+#  class              YES        YES        NO    YES     NO      YES         YES         YES
 #
-#  userdefined        YES        YES        NO    NO      YES     YES          YES         YES
+#  userdefined        YES        YES        NO    NO      YES     YES         YES         YES
 #
 # tclObj + converterArg (alnum..xdigit)            Attribute ... -type alnum
 # object + converterArg (some class, e.g. ::C)     Attribute ... -type ::C    Attribute -type object -arg ::C