Index: generic/nsf.c
===================================================================
diff -u -rd1ed482555d4d28dbb41fb9ca2723eabb5e01221 -r5c038339ae2886d3b1ef4dfb681d395e4f3af9e5
--- generic/nsf.c	(.../nsf.c)	(revision d1ed482555d4d28dbb41fb9ca2723eabb5e01221)
+++ generic/nsf.c	(.../nsf.c)	(revision 5c038339ae2886d3b1ef4dfb681d395e4f3af9e5)
@@ -11641,7 +11641,7 @@
 
 static int
 ProtectionMatches(Tcl_Interp *interp, int withCallprotection, Tcl_Command cmd) {
-  int result, isProtected = Tcl_Command_flags(cmd) & NSF_CMD_PROTECTED_METHOD;
+  int result, isProtected = (Tcl_Command_flags(cmd) & NSF_CMD_PROTECTED_METHOD) != 0;
   if (withCallprotection == CallprotectionNULL) {
     withCallprotection = CallprotectionPublicIdx;
   }