1 files changed, 4 insertions, 1 deletions
diff --git a/include/qom/object.h b/include/qom/object.h
index 7793557289..9192265db7 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -573,12 +573,15 @@ struct InterfaceInfo {
  *
  * The class for all interfaces.  Subclasses of this class should only add
  * virtual methods.
+ *
+ * Note that most of the fields of ObjectClass are unused (all except
+ * "type", in fact).  They are only present in InterfaceClass to allow
+ * @object_class_dynamic_cast to work with both regular classes and interfaces.
  */
 struct InterfaceClass
 {
     ObjectClass parent_class;
     /* private: */
-    ObjectClass *concrete_class;
     Type interface_type;
 };