pkg/front_end/testcases/extension_types/issue53610.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 const N(Null _) {}

void main() {
  var n = N(null);
  const cn = N(null);
}