Index: generic/nsf.c
===================================================================
diff -u -r3b2edfa776291682e0d251322997aad328b885df -r8db56ce1f1dff5e22768c59df1b9039e961c6267
--- generic/nsf.c	(.../nsf.c)	(revision 3b2edfa776291682e0d251322997aad328b885df)
+++ generic/nsf.c	(.../nsf.c)	(revision 8db56ce1f1dff5e22768c59df1b9039e961c6267)
@@ -6846,6 +6846,8 @@
       nameStringObj = Tcl_NewStringObj(pPtr->name, -1);
       if (pPtr->type) {
         ParamDefsFormatOption(interp, nameStringObj, pPtr->type, &colonWritten, &first);
+      } else if (isNonpos && pPtr->nrArgs == 0) {
+        ParamDefsFormatOption(interp, nameStringObj, "switch", &colonWritten, &first);
       }
       if (outputRequired) {
         ParamDefsFormatOption(interp, nameStringObj, "required", &colonWritten, &first);