tests/language/implicit_downcast_during/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] COMPILE_TIME_ERROR.ARGUMENT_TYPE_NOT_ASSIGNABLE
  // [cfe] The argument type 'A' can't be assigned to the parameter type 'B'.
}