// @dart = 2.9
class Class {}

extension Extension on Class {
  void method1({bool b = false, String s = ', '}) => null;
  void method2([bool b = false, String s = ', ']) => null;
  void method3(int i, {bool b = false, String s = ', '}) {}
  void method4(int i, [bool b = false, String s = ', ']) {}
}

main() {}