pkg/front_end/testcases/inference/future_union_downwards.dart

// Copyright (c) 2017, 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.

library test;

import 'dart:async';

class MyFuture<T> implements Future<T> {
  MyFuture() {}
  MyFuture.value([x]) {}
  dynamic noSuchMethod(invocation) => null;
  MyFuture<S> then<S>(FutureOr<S> f(T x), {Function? onError}) => throw '';
}

MyFuture f = throw '';
// Instantiates Future<int>
Future<int> t1 = f.then((_) => new Future.value('hi'));

// Instantiates List<int>
Future<List<int>> t2 = f.then((_) => [3]);
Future<List<int>> g2() async {
  return [3];
}

Future<List<int>> g3() async {
  return new Future.value([3]);
}

main() {}