diff --git a/src/google/protobuf/dynamic_message.cc b/src/google/protobuf/dynamic_message.cc
index 865280c..8ad6f84 100644
--- a/src/google/protobuf/dynamic_message.cc
+++ b/src/google/protobuf/dynamic_message.cc
@@ -411,7 +411,11 @@ struct DynamicMessageFactory::TypeInfo {
           &DynamicMessage::MergeImpl,
           internal::MessageCreator(),  // to be filled later
           &DynamicMessage::DestroyImpl,
+#if defined(PROTOBUF_CUSTOM_VTABLE)
           static_cast<void (MessageLite::*)()>(&DynamicMessage::ClearImpl),
+#else
+          nullptr,
+#endif  // PROTOBUF_CUSTOM_VTABLE
           DynamicMessage::ByteSizeLongImpl,
           DynamicMessage::_InternalSerializeImpl,
           PROTOBUF_FIELD_OFFSET(DynamicMessage, cached_byte_size_),
@@ -1059,7 +1063,11 @@ const Message* DynamicMessageFactory::GetPrototypeNoLock(
               internal::MessageCreator(DynamicMessage::NewImpl, size,
                                        kSafeAlignment),
               &DynamicMessage::DestroyImpl,
+#if defined(PROTOBUF_CUSTOM_VTABLE)
               static_cast<void (MessageLite::*)()>(&DynamicMessage::ClearImpl),
+#else
+              nullptr,
+#endif  // PROTOBUF_CUSTOM_VTABLE
               DynamicMessage::ByteSizeLongImpl,
               DynamicMessage::_InternalSerializeImpl,
               PROTOBUF_FIELD_OFFSET(DynamicMessage, cached_byte_size_),