Opacity widget's child should not be nullable (#484)
diff --git a/packages/animations/lib/src/open_container.dart b/packages/animations/lib/src/open_container.dart
index bec071c..24523ec 100644
--- a/packages/animations/lib/src/open_container.dart
+++ b/packages/animations/lib/src/open_container.dart
@@ -342,10 +342,10 @@
class _Hideable extends StatefulWidget {
const _Hideable({
Key? key,
- this.child,
+ required this.child,
}) : super(key: key);
- final Widget? child;
+ final Widget child;
@override
State<_Hideable> createState() => _HideableState();