avoid_unnecessary_containers  
            
            Avoid unnecessary containers.
This rule is available as of Dart 2.7.0.
Rule sets: flutter
This rule has a quick fix available.
Details
AVOID wrapping widgets in unnecessary containers.
Wrapping a widget in Container with no other parameters set has no effect 
and makes code needlessly more complex.
BAD:
Widget buildRow() {
  return Container(
      child: Row(
        children: <Widget>[
          const MyLogo(),
          const Expanded(
            child: Text('...'),
          ),
        ],
      )
  );
}
GOOD:
Widget buildRow() {
  return Row(
    children: <Widget>[
      const MyLogo(),
      const Expanded(
        child: Text('...'),
      ),
    ],
  );
}
Usage
To enable the avoid_unnecessary_containers rule,
add avoid_unnecessary_containers under linter > rules in your
analysis_options.yaml
file:
linter:
  rules:
    - avoid_unnecessary_containers