Index: src/runtime/class.m
==================================================================
--- src/runtime/class.m
+++ src/runtime/class.m
@@ -858,11 +858,11 @@
 	if (rcls->dtable != NULL && rcls->dtable != empty_dtable)
 		objc_dtable_free(rcls->dtable);
 
 	rcls->dtable = NULL;
 
-	if (rcls->superclass != Nil)
+	if ((rcls->info & OBJC_CLASS_INFO_SETUP) && rcls->superclass != Nil)
 		cls->superclass = rcls->superclass->name;
 
 	rcls->info &= ~OBJC_CLASS_INFO_SETUP;
 }