diff --git a/lib/src/form_field.dart b/lib/src/form_field.dart
index b4fec16..d11a4ff 100644
--- a/lib/src/form_field.dart
+++ b/lib/src/form_field.dart
@@ -73,7 +73,5 @@ class DateTimeFormField extends FormField<DateTime> {
         );
 
   @override
-  _DateFormFieldState createState() => _DateFormFieldState();
+  FormFieldState<DateTime> createState() => FormFieldState<DateTime>();
 }
-
-class _DateFormFieldState extends FormFieldState<DateTime> {}