// 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 {}

class B extends A {
  B operator +(int i) => this;
}

B get topLevel => new B();

void set topLevel(A value) {}

main() {
  topLevel += 1;
}