class A {
  foo({bool? c = true, bool? a}) {}
}

class B extends A {
  foo({c = true, bool? a}) {}
}

class C extends B {
  foo({bool? c = true, bool? a}) {}
}

class A1 {
  foo({bool? a = true, bool? c}) {}
}

class B1 extends A1 {
  foo({a = true, bool? c}) {}
}

class C1 extends B1 {
  foo({bool? a = true, bool? c}) {}
}

main() {}