LanguageFeatures/Spread-collections/DynamicSemantics_List_A02_t04.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 elements are added to the result list in correct
/// order.
/// @author iarkh@unipro.ru

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

class MyIterable extends IterableBase {
  late List list;

  MyIterable(this.list);

  Iterator get iterator => MyIterator(list);
}

class MyIterator implements Iterator {
  int i = -1;
  late List list;

  MyIterator(List aList) { list = aList; }

  @override
  bool moveNext() { return ++i < list.length; }

  @override
  dynamic get current { return list[i]; }
}

List aList = [11, 28];
Set aSet = {};

Iterable it1 = new MyIterable([1, 2, 3, 4, 5]);
Iterable it2 = new MyIterable(["a", "14", "1", "2", null, 143, aList]);
Iterable it3 = [100, 200, aSet, aList, 300];
Iterable it4 = [];
Iterable? it5 = null;

main() {
  Expect.listEquals(
      [-1, -2, -3, 1, 2, 3, 4, 5, 6, 7], [-1, -2, -3, ...it1, 6, 7]);
  Expect.listEquals(
      [-1, -2, -3, 1, 2, 3, 4, 5, 6, 7], [-1, -2, -3, ...?it1, 6, 7]);
//                                                    ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
  Expect.listEquals([1, 2, 3], [1, ...it4, 2, ...?it4, 3, ...?it5]);
//                                            ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
  Expect.listEquals([-9, -8, 1, 2, 3, 4, 5, -7, "a", "14", "1", "2", null, 143,
          aList, -6, 100, 200, aSet, aList, 300, -5, -4, -3, -2],
      [-9, -8, ...it1, -7, ...?it2, -6, ...it3, -5, -4, ...it4, -3, -2]);
//                         ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
}