Index: generic/nsf.c
===================================================================
diff -u -rdadf28efd0707ae40076f49837e6b45ad5b2a989 -re5a42b6e8b73958a2532bfe604f16c3cab32cb62
--- generic/nsf.c	(.../nsf.c)	(revision dadf28efd0707ae40076f49837e6b45ad5b2a989)
+++ generic/nsf.c	(.../nsf.c)	(revision e5a42b6e8b73958a2532bfe604f16c3cab32cb62)
@@ -8894,7 +8894,7 @@
   /*
    * Iterate over the subclass hierarchy.
    */
-  for (; likely(subClasses != NULL); subClasses = subClasses->nextPtr) {
+  do {
     Tcl_HashSearch hSrch;
     Tcl_HashEntry *hPtr;
     Tcl_HashTable *instanceTablePtr;
@@ -8923,7 +8923,8 @@
         object->flags &= ~NSF_MIXIN_ORDER_VALID;
       }
     }
-  }
+    subClasses = subClasses->nextPtr;
+  } while (subClasses != NULL);
 
 }
 
@@ -9334,14 +9335,16 @@
   nonnull_assert(name != NULL);
   nonnull_assert(clPtr != NULL);
 
-  for (; likely(mixinList != NULL);  mixinList = mixinList->nextPtr) {
+  do {
     NsfClass *foundCl = NsfGetClassFromCmdPtr(mixinList->cmdPtr);
 
     if ((foundCl != NULL) && SearchCMethod(foundCl, name, &cmd)) {
       *clPtr = foundCl;
       return cmd;
     }
-  }
+    mixinList = mixinList->nextPtr;
+  } while (mixinList != NULL);
+
   return NULL;
 }