Index: ChangeLog
===================================================================
diff -u -ra65ff6b8258c66e5e7bb6c4e8567111baa0f08a3 -r802641dc2edee9e8ac569ad9c9cbadc949df8d47
--- ChangeLog	(.../ChangeLog)	(revision a65ff6b8258c66e5e7bb6c4e8567111baa0f08a3)
+++ ChangeLog	(.../ChangeLog)	(revision 802641dc2edee9e8ac569ad9c9cbadc949df8d47)
@@ -1,3 +1,10 @@
+2008-12-01 <Gustaf.Neumann@wu-wien.ac.at>
+    * Correct deletion of user-metaclasses: Deletion of
+      user-metaclasses could lead to undestroyable objects, since the
+      instances of the user-metaclasses were reclassed to
+      ::xotcl::Object instead of ::xotcl::Class.
+    * extend regression test for such situations
+
 2008-11-02 <Gustaf.Neumann@wu-wien.ac.at>
     * Release of XOTcl 1.6.2
 
Index: generic/xotcl.c
===================================================================
diff -u -rda111296df2bd2460f13bce2ebbd2c4a69027ae8 -r802641dc2edee9e8ac569ad9c9cbadc949df8d47
--- generic/xotcl.c	(.../xotcl.c)	(revision da111296df2bd2460f13bce2ebbd2c4a69027ae8)
+++ generic/xotcl.c	(.../xotcl.c)	(revision 802641dc2edee9e8ac569ad9c9cbadc949df8d47)
@@ -7643,20 +7643,36 @@
   NSDeleteChildren(interp, cl->nsPtr);
 
   if (!softrecreate) {
-    /* reset all instances to the class ::xotcl::Object, that makes no sense
-       for ::Object itself */
+    /* Reclass all instances of the current class the the appropriate
+       most general class ("baseClass"). The most general class of a
+       metaclass is ::xotcl::Class, the most general class of an
+       object is ::xotcl::Object. Instances of metaclasses can be only
+       reset to ::xotcl::Class (and not to ::xotcl::Object as in
+       earlier versions), since otherwise their instances can't be
+       deleted, because ::xotcl::Object has no method "instdestroy".
+       
+       We do not have to reclassing in case, cl == ::xotcl::Object
+    */
     if (cl != theobj) {
+      XOTclClass *baseClass = IsMetaClass(interp, cl) ? RUNTIME_STATE(interp)->theClass : theobj;
+      if (baseClass == cl) {
+        /* During final cleanup, we delete ::xotcl::Class; there are
+           no more Classes or user objects available at that time, so
+           we reclass to ::xotcl::Object.
+        */
+        baseClass = theobj;
+      }
       hPtr = &cl->instances ? Tcl_FirstHashEntry(&cl->instances, &hSrch) : 0;
       for (; hPtr != 0; hPtr = Tcl_NextHashEntry(&hSrch)) {
         XOTclObject *inst = (XOTclObject*)Tcl_GetHashKey(&cl->instances, hPtr);
         if (inst && inst != (XOTclObject*)cl && inst->id) {
-          if (inst != &(theobj->object)) {
+          if (inst != &(baseClass->object)) {
             (void)RemoveInstance(inst, cl->object.cl);
-            AddInstance(inst, theobj);
+            AddInstance(inst, baseClass);
           }
         }
       }
-    }
+    } 
     Tcl_DeleteHashTable(&cl->instances);
     MEM_COUNT_FREE("Tcl_InitHashTable",&cl->instances);
   }
Index: tests/testx.xotcl
===================================================================
diff -u -r0037211cd9632cbb418f9f8ca40a001a51d1598d -r802641dc2edee9e8ac569ad9c9cbadc949df8d47
--- tests/testx.xotcl	(.../testx.xotcl)	(revision 0037211cd9632cbb418f9f8ca40a001a51d1598d)
+++ tests/testx.xotcl	(.../testx.xotcl)	(revision 802641dc2edee9e8ac569ad9c9cbadc949df8d47)
@@ -3326,9 +3326,9 @@
   ::errorCheck [Object ismetaclass M] 0 "is metaclass 0"
   ::errorCheck [M isclass] 0 "is isclass 0"
   ::errorCheck [Class info instances M] "" "is not an instance of Class"
-  ::errorCheck [m1 info class] ::xotcl::Object "m1 is now an instance of Object"
+  ::errorCheck [m1 info class] ::xotcl::Class "m1 is now an instance of Class"
   ::errorCheck [m1 isclass] 1 "m1 is isclass 1"
-  ::errorCheck [m1 info class] ::xotcl::Object "m1 is of class ::xotcl::Object"
+  ::errorCheck [m1 info class] ::xotcl::Class "m1 is of class ::xotcl::Class"
   M destroy
   
   # to be completed XXX