Index: generic/nsf.c
===================================================================
diff -u -N -r7b03a5476b57153b65a849aebe6924e16ab46aa0 -r57e3f532bb855908a3af3ed1fbb81a673de0bd68
--- generic/nsf.c	(.../nsf.c)	(revision 7b03a5476b57153b65a849aebe6924e16ab46aa0)
+++ generic/nsf.c	(.../nsf.c)	(revision 57e3f532bb855908a3af3ed1fbb81a673de0bd68)
@@ -32445,10 +32445,16 @@
                          NsfMethodName(objv[0]));
   }
 
-  result = TclObjGetFrame(interp, objv[1], &requestedFramePtr);
-  if (unlikely(result == -1)) {
-    return TCL_ERROR;
+
+  if (objc == 2) {
+    result = 0;
+  } else {
+    result = TclObjGetFrame(interp, objv[1], &requestedFramePtr);
+    if (unlikely(result == -1)) {
+      return TCL_ERROR;
+    }
   }
+  
   objc -= result + 1;
   if (objc == 0) {
     goto wrongArgs;