LanguageFeatures/Control-flow-collections/type_inference_A01_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 If a list literal has a downwards inference type of List<T> for
/// some T, then the downwards inference context type of the body elements is T.
///
/// @description Checks that if a list literal has a downwards inference type of
/// List<T> for some T, then the downwards inference context type of the body
/// elements is T.
/// @author sgrekhov@unipro.ru

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

class C {}

main() {
  List<List<String>> list1 = [
    if (true) [],
    if (false) [] else [],
    for (var i = 0; i < 1; i++) []
  ];
  Expect.isTrue(list1 is List<List<String>>);
  Expect.runtimeIsType<List<List<String>>>(list1);
  Expect.listEquals([[], [], []], list1);

  var list2 = <List<int>> [
    if (true) [],
    if (false) [] else [],
    for (var i = 0; i < 1; i++) []
  ];
  Expect.isTrue(list2 is List<List<int>>);
  Expect.runtimeIsType<List<List<int>>>(list2);
  Expect.listEquals([[], [], []], list2);

  var list3 = const <List<String>> [
    if (true) [],
    if (false) [] else [],
  ];
  Expect.isTrue(list3 is List<List<String>>);
  Expect.runtimeIsType<List<List<String>>>(list3);
  Expect.listEquals([[], []], list3);

  const list4 = <List<C>> [
    if (true) [],
    if (false) [] else []
  ];
  Expect.isTrue(list4 is List<List<C>>);
  Expect.runtimeIsType<List<List<C>>>(list4);
  Expect.listEquals([[], []], list4);
}