Index: generic/nsf.c
===================================================================
diff -u -N -r11c5ccdc7e2da4b07cd5ef23dc69dcb14e10de0c -r6028c95c4c4f96815c25ab8dc9760ab2a2dd901b
--- generic/nsf.c	(.../nsf.c)	(revision 11c5ccdc7e2da4b07cd5ef23dc69dcb14e10de0c)
+++ generic/nsf.c	(.../nsf.c)	(revision 6028c95c4c4f96815c25ab8dc9760ab2a2dd901b)
@@ -5707,26 +5707,27 @@
         VarHashRefCount(varPtr)++;
         if ((varPtr->flags & VAR_TRACED_UNSET) != 0u /* TclIsVarTraced(varPtr) */) {
           (void)UnsetInstVar(interp, 1 /* no error msg */, object, ObjStr(nameObj));
-        }
-        if (TclIsVarTraced(varPtr)) {
-          Tcl_HashEntry *tPtr = Tcl_FindHashEntry(&iPtr->varTraces, varPtr);
-          VarTrace *tracePtr = Tcl_GetHashValue(tPtr);
-          ActiveVarTrace *activePtr;
-          
-          while (tracePtr) {
-            VarTrace *prevPtr = tracePtr;
+
+          if (TclIsVarTraced(varPtr)) {
+            Tcl_HashEntry *tPtr = Tcl_FindHashEntry(&iPtr->varTraces, varPtr);
+            VarTrace *tracePtr = Tcl_GetHashValue(tPtr);
+            ActiveVarTrace *activePtr;
             
-            tracePtr = tracePtr->nextPtr;
-            prevPtr->nextPtr = NULL;
-            Tcl_EventuallyFree(prevPtr, TCL_DYNAMIC);
-          }
-          Tcl_DeleteHashEntry(tPtr);
-          varPtr->flags &= ~VAR_ALL_TRACES;
-          for (activePtr = iPtr->activeVarTracePtr; activePtr != NULL;
-               activePtr = activePtr->nextPtr) {
-            if (activePtr->varPtr == varPtr) {
-              activePtr->nextTracePtr = NULL;
+            while (tracePtr) {
+              VarTrace *prevPtr = tracePtr;
+              
+              tracePtr = tracePtr->nextPtr;
+              prevPtr->nextPtr = NULL;
+              Tcl_EventuallyFree(prevPtr, TCL_DYNAMIC);
             }
+            Tcl_DeleteHashEntry(tPtr);
+            varPtr->flags &= ~VAR_ALL_TRACES;
+            for (activePtr = iPtr->activeVarTracePtr; activePtr != NULL;
+                 activePtr = activePtr->nextPtr) {
+              if (activePtr->varPtr == varPtr) {
+                activePtr->nextTracePtr = NULL;
+              }
+            }
           }
         }
         VarHashRefCount(varPtr)--;