/*
 * Copyright (c) 2019, 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.
 */
/**
 * @assertion From the Unified collection Spec:
 * A [spreadElement] starting with [...?] is a constant element if its
 * expression is constant and it evaluates to [null] or a constant [List], [Set]
 * or [Map] instance originally created by a list, set or map literal. It is a
 * potentially constant element if the expression is potentially constant
 * expression.
 * @description: Checks that constant set spread [...?] element can be constant
 * list or set or [null].
 * @static-warning
 * @author iarkh@unipro.ru
 */

const Set? empty = {};

main() {
  const Set res1 = const {...?[1, 2, 3], 4};
  const Set res2 = const {...?([1, 2, 3] as List?), 4};
  const Set res3 = const {5, ...?{2, 11}};
  const Set res4 = const {5, ...?({2, 11} as Set?)};
  const Set res5 = const {...?{}};
  const Set res7 = const {...?null};
  const Set res8 = const {...?empty};
}