import 'dart:async';

class A {
  const A();
}

class B extends A {}

class C {
  num? call() {}
}

void fooContext(A x) {}
void barContext(List<A> x) {}
void bazContext(num Function() f) {}
A foo(B? x, List<B?> l, Map<B?, B?> m, List<B>? l2, Map<B, B>? m2) {}
List<A> bar(List<B?> x, List<List<B?>> l, Map<List<B?>, List<B?>> m) {}
void baz(C c) {}
A boz(Null x) {}
main() {}