Exhaustiveness

main.dart

import 'dart:math';

sealed class Shape {}

class Square extends Shape {
  Square(this.length, this.width);
  final double length;
  final double width;
}

class Circle extends Shape {
  Circle(this.radius);
  final double radius;
}

double calculateArea(Shape shape) => switch (shape) {
      Square(length: var l, width: var w) => l * w,
      Circle(radius: var r) => pi * r * r
    };

void main() {
  Shape shape = Square(3, 3);
  print(calculateArea(shape));
  shape = Circle(3);
  print(calculateArea(shape));
}