pkg/front_end/testcases/extension_types/issue53485.dart

// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by b
// BSD-style license that can be found in the LICENSE file.

extension type I(int id) {
  void set id(int i) {}
}

extension type ET1(int id) {
  void set id(int i) {}
}

extension type ET2(int id) implements I {}

main() {
  ET1 et1 = ET1(1);
  et1.id = 0;

  ET2 et2 = ET2(2);
  et2.id = 0;
}