LanguageFeatures/Spread-collections/Syntax_A03_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 This grammar is ambiguous in cases like [{ ...a }] because
/// [mapLiteral], [setLiteral], and [mapOrSetLiteral] all match. In cases of
/// ambiguity like this, [mapOrSetLiteral] is always chosen. Then the
/// disambiguation happens based on the static types, below. It is not ambiguous
/// if the collection has any type arguments. If there is one, it's a set. If
/// two, a map. Otherwise, it's an error.
/// @description Checks that it is a set if collection has one type argument, it
/// is a map if collection has two arguments and exception is thrown if there are
/// three or more type arguments.
/// @author iarkh@unipro.ru

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

main() {
  var a;
  Expect.isTrue(<int>{} is Set);
  Expect.isTrue(<int, int>{} is Map);
  Expect.runtimeIsType<Set>(<int>{});
  Expect.runtimeIsType<Map>(<int, int>{});
}