pkg/front_end/testcases/extension_types/field_initializer.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 a
// BSD-style license that can be found in the LICENSE file.

extension type ET1(int id) {
  int id = 0;
}

extension type ET2(int id) {
  int x = 0;
}

extension type ET3(int id) {
  final int x = 0;
}