tests/language_2/inference/inconsistent_inheritance_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.

// @dart = 2.9

class A {
  void f(Object x) {}
}

class B {
  void f(String x) {}
}

class C extends A implements B {
  void f(x) {}
}

void main() {}