LanguageFeatures/Spread-collections/DynamicSemantics_List_A02_t01.dart

// 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 A list literal <E>[elem_1 ... elem_n] is evaluated as follows:
///
/// 2. For each element in the list literal:
///   i. Evaluate the element's expression to a value value.
///   ii. If element is a spread element:
///     a. If element is null-aware and value is [null], continue to the next
///        element in the literal.
///     b. Evaluate [value.iterator] to a [value] iterator.
///     c. Loop:
///        a. If [iterator.moveNext()] returns [false], exit the loop.
///        b. Evaluate [iterator.current] and append the result to list.
///   iii. Else:
///     a. Append value to list.
///
/// @description Checks that if element is null-aware and it's [null], nothing
/// added to the result list.
/// @author iarkh@unipro.ru


import "../../Utils/expect.dart";

List list1 = [1, 2, 3, 4, 5];
List list2 = [];
List? list3 = null;
List list4 = [1 ,2, 3, "checkme"];

main() {
  Expect.listEquals([], [...?list3]);
  Expect.listEquals([1, 2, 4], [1, 2, ...?list3, 4]);
  Expect.listEquals([1, 1, 2, 3, "checkme", 1, 2, 3, 4, 5],
      [1, ...?list4, ...?list3, ...list1]);
//        ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//            ^
// [cfe] Operand of null-aware operation '...?' has type 'List<dynamic>' which excludes null.
  Expect.listEquals([], [...?list3, ...?list3, ...?list3]);
  Expect.listEquals([], [...list2, ...?list3]);
}