LanguageFeatures/Spread-collections/Ambiguity_A04_t05.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 (Unified collections) Let [e] be a [setOrMapLiteral].
///
/// If [e] has a context [C], and the base type of [C] is [Cbase] (that is,
/// [Cbase] is [C] with all wrapping [FutureOrs] removed), and [Cbase] is not
/// [?], then let [S] be the greatest closure.
///
/// If [e] has [typeArguments] then:
/// ...
/// If there are exactly two type arguments [K] and [V], then [e] is a map
/// literal with static type [Map<K, V>].
///
/// @description Checks that [setOrMapLiteral] has two type argument, it's a map.
/// @author iarkh@unipro.ru

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

main() {
  dynamic aSet = {1, 2, 3};
  dynamic aList = [1, 2, 3];
  dynamic aMap = {1: 1, 2: 2, 3: 3};

  var res1 = <int, int>{...?aMap};
  Expect.isTrue(res1 is Map);
  Expect.runtimeIsType<Map>(res1);

  var res2;
  Expect.throws(() => res2 = <int, int>{...aList});
  Expect.throws(() => res2 = <int, int>{...aSet});
}