LanguageFeatures/Spread-collections/TypeInference_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 If a spread element in a list or set literal has static type
 * [Iterable<T>] for some [T], then the upwards inference element type is [T].
 * @description Checks that spread element upwards inference element type is [T]
 * in the list literal
 * @static-warning
 * @author iarkh@unipro.ru
 */

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

class A {}
class B extends A {}
class C extends B {}

main() {
  List<A> a_list        = <A>[new A()];
  List<B> b_list        = <B>[new B()];
  List<C> c_list        = <C>[new C()];
  List<int> int_list    = <int>[1, 2, 3];
  List<String> str_list = <String>["string"];

  A a = new A();
  B b = new B();
  C c = new C();

  Expect.isTrue([...int_list] is List<int>);
  Expect.isTrue(["test", "a", ...?str_list, "ooooo"] is List<String>);

  Expect.isTrue([...a_list] is List<A>);
  Expect.isTrue([a, ...?a_list] is List<A>);
  Expect.isTrue([...b_list] is List<A>);
  Expect.isTrue([a, ...?b_list] is List<A>);
  Expect.isTrue([...c_list] is List<A>);
  Expect.isTrue([a, ...?c_list] is List<A>);
  Expect.isTrue([a, ...a_list, ...b_list, b] is List<A>);
  Expect.isTrue([a, b, c, ...a_list, ...b_list, ...?c_list] is List<A>);
  Expect.isTrue([a, ...a_list, ...b_list, b] is List<A>);

  Expect.isFalse([...a_list] is List<B>);
  Expect.isFalse([b, ...?a_list] is List<B>);
  Expect.isTrue([...b_list] is List<B>);
  Expect.isTrue([b, ...?b_list] is List<B>);
  Expect.isTrue([...c_list] is List<B>);
  Expect.isTrue([b, ...?c_list] is List<B>);
  Expect.isFalse([c, ...a_list, ...b_list, b] is List<B>);
  Expect.isFalse([b, c, ...a_list, ...b_list, ...?c_list] is List<B>);
  Expect.isTrue([b, ...c_list, ...b_list, b] is List<B>);

  Expect.isFalse([...a_list] is List<C>);
  Expect.isFalse([c, ...?a_list] is List<C>);
  Expect.isFalse([...b_list] is List<C>);
  Expect.isFalse([c, ...?b_list] is List<C>);
  Expect.isTrue([...c_list] is List<C>);
  Expect.isTrue([...?c_list] is List<C>);
  Expect.isTrue([c, ...?c_list] is List<C>);
  Expect.isFalse([c, ...a_list, ...b_list, c] is List<C>);
  Expect.isFalse([c, ...a_list, ...b_list, ...?c_list] is List<C>);
  Expect.isFalse([a, ...c_list, ...b_list, b] is List<C>);
}