Index: generic/nsf.c
===================================================================
diff -u -r42f380056d1453bbdf852086060d2cf5e40155d8 -r392fda7d21bb87b5727efd57ec51d07fcf4547f4
--- generic/nsf.c	(.../nsf.c)	(revision 42f380056d1453bbdf852086060d2cf5e40155d8)
+++ generic/nsf.c	(.../nsf.c)	(revision 392fda7d21bb87b5727efd57ec51d07fcf4547f4)
@@ -24993,6 +24993,8 @@
   nonnull_assert(methodName != NULL);
   nonnull_assert(tcd != NULL);
 
+  /*fprintf(stderr, "AliasRefetch %s\n", methodName);*/
+
   defObject = (tcd->class != NULL) ? &(tcd->class->object) : object;
 
   /*
@@ -25083,7 +25085,7 @@
     AliasCmdClientData *tcd = (AliasCmdClientData *)Tcl_Command_objClientData(cmd);
 
     assert(tcd != NULL);
-
+    /*fprintf(stderr, "AliasDereference %s epoch %d\n",methodName, Tcl_Command_cmdEpoch(tcd->aliasedCmd));*/
     if (unlikely(Tcl_Command_cmdEpoch(tcd->aliasedCmd) != 0)) {
 
       /*fprintf(stderr, "NsfProcAliasMethod aliasedCmd %p epoch %p\n",
@@ -26334,13 +26336,16 @@
   newTargetObject = NsfGetObjectFromCmdPtr(cmd);
 
   if (oldCmd != NULL) {
-
-    NSDeleteCmd(interp, nsPtr, methodName);
-#if 0
-    //fprintf(stderr, "... DELETE preexisting cmd %s in ns %s\n", methodName, nsPtr->fullName);
-
+#if 1
+    /*
+     * Old solution, leasds to a broken regression test with Tcl 8.7a1.
+     * However, using Tcl_DeleteCommandFromToken() leads to a crash also with
+     * earlier solutions when defining recursive aliases.
+     */
     NsfObject  *oldTargetObject;
 
+    /*fprintf(stderr, "... DELETE preexisting cmd %s in ns %s\n", methodName, nsPtr->fullName);*/
+
     oldTargetObject = NsfGetObjectFromCmdPtr(oldCmd);
     /* fprintf(stderr, "oldTargetObject %p flags %.6x newTargetObject %p\n",
        oldTargetObject, (oldTargetObject != NULL) ? oldTargetObject->flags : 0, newTargetObject);*/
@@ -26357,6 +26362,9 @@
       assert(oldTargetObject->refCount > 0);
       AliasDeleteObjectReference(interp, oldCmd);
     }
+
+#else
+    Tcl_DeleteCommandFromToken(interp, oldCmd);
 #endif
 
   }
Index: tests/alias.test
===================================================================
diff -u -r52af84c2682d91994f00f6f1cfdf7e9f5fda0a62 -r392fda7d21bb87b5727efd57ec51d07fcf4547f4
--- tests/alias.test	(.../alias.test)	(revision 52af84c2682d91994f00f6f1cfdf7e9f5fda0a62)
+++ tests/alias.test	(.../alias.test)	(revision 392fda7d21bb87b5727efd57ec51d07fcf4547f4)
@@ -792,6 +792,7 @@
     ? [list [:] public object alias foo $handle] "::o::foo"
   }
   # at runtime, we get an exception
+  puts stderr ======
   ? {o foo} {target "::o::foo" of alias foo apparently disappeared}
 
   # test indirect case