prefer-const-border-radius

added in: 1.0.0performance

BorderRadius.circular constructor calls const BorderRadius.all constructor under the hood. This rule allows to replace BorderRadius.circular(value) with const BorderRadius.all(Radius.circular(value)) if radius is a constant value.

Example

Bad:

final _defaultFinalRadius = BorderRadius.circular(8); // LINT

class RoundedWidget extends StatelessWidget {
  final BorderRadius borderRadius;
  final Widget child;

  const RoundedWidget({
    Key? key,
    this.borderRadius = _defaultRadius,
    required this.child,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return ClipRRect(
      borderRadius: borderRadius,
      child: child,
    );
  }
}

Good:

const _defaultRadius = BorderRadius.all(Radius.circular(8));

class RoundedWidget extends StatelessWidget {
  final BorderRadius borderRadius;
  final Widget child;

  const RoundedWidget({
    Key? key,
    this.borderRadius = _defaultRadius,
    required this.child,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return ClipRRect(
      borderRadius: borderRadius,
      child: child,
    );
  }
}