tests/language/implicit_downcast_during/null_aware_method_invocation_test.dart

// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

class A {}

class B extends A {}

class C {
  void f(B b) {}
}

main() {
  C? c = new C();
  A a = new B();
  c?.f(a);
//     ^
// [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
// [cfe] The argument type 'A' can't be assigned to the parameter type 'B'.
}