pkg/front_end/testcases/extensions/null_aware_set.dart

// Copyright (c) 2022, 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.

extension on Object {
  set f(int x) {}
}

void fun(String? s) {
  s?.f = 1;
}