pkg/analyzer/lib/src/utilities/extensions/collection.dart

// Copyright (c) 2021, 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 ListExtension<E> on List<E> {
  void addIfNotNull(E? element) {
    if (element != null) {
      add(element);
    }
  }
}