Index: generic/nsf.c
===================================================================
diff -u -r5a34df6ef70a354e29438bc9a7c553c0fb8b9677 -r54277a59a45fb6f055637b9a0e14a2fefd31f7eb
--- generic/nsf.c	(.../nsf.c)	(revision 5a34df6ef70a354e29438bc9a7c553c0fb8b9677)
+++ generic/nsf.c	(.../nsf.c)	(revision 54277a59a45fb6f055637b9a0e14a2fefd31f7eb)
@@ -26054,7 +26054,8 @@
   int              result, objc;
 
   result = ParamDefsParse(interp, NsfGlobalObjs[NSF_PARSE_ARGS], argspecObj,
-                          NSF_DISALLOWED_ARG_METHOD_PARAMETER, 0,
+                          NSF_DISALLOWED_ARG_METHOD_PARAMETER, 1 /* force use of param structure, 
+                                                                    even for Tcl-only params */,
                           &parsedParam);
 
   if (unlikely(result != TCL_OK)) {
Index: tests/parameters.test
===================================================================
diff -u -rdc801eacd9d3d6f63b53830aef0fec2e0b71134c -r54277a59a45fb6f055637b9a0e14a2fefd31f7eb
--- tests/parameters.test	(.../parameters.test)	(revision dc801eacd9d3d6f63b53830aef0fec2e0b71134c)
+++ tests/parameters.test	(.../parameters.test)	(revision 54277a59a45fb6f055637b9a0e14a2fefd31f7eb)
@@ -3367,6 +3367,10 @@
 
     ? {set bar} 2
     ? {set baz} hi
+
+    ? {apply {{} {nsf::parseargs a 1; info exists a}}} "1"
+    ? {apply {{} {nsf::parseargs {a b} {1 2}; expr {[info exists a]+[info exists b]}}}} "2"
+    ? {apply {{} {nsf::parseargs {a b args} {1 2 3 4}; expr {[info exists a]+[info exists b]+[info exists args]}}}} "3"
   }
 
 #