Robert Nystrom
fc1b1ecc71
Change-Id: Idbcc965a27e9ffeedf5e0a1068b019de4193070f Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/127745 Commit-Queue: Bob Nystrom <rnystrom@google.com> Reviewed-by: Alexander Thomas <athom@google.com>
42 lines
1.7 KiB
Dart
42 lines
1.7 KiB
Dart
// Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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import 'dart:async';
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class Derived<T> implements Future<T> {
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noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
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}
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class FixedPoint<T> implements Future<FixedPoint<T>> {
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noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
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}
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class Divergent<T> implements Future<Divergent<Divergent<T>>> {
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noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
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}
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test() async {
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// flatten(Derived<int>) = int
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int x = await new Derived<int>(); //# 01: runtime error
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Future<int> f() async => new Derived<int>(); //# 02: ok
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Future<int> f() async { return new Derived<int>(); } //# 03: ok
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Future<int> x = (() async => new Derived<int>())(); //# 04: runtime error
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// flatten(FixedPoint<int>) = FixedPoint<int>
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FixedPoint<int> x = await new FixedPoint<int>(); //# 05: runtime error
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Future<FixedPoint<int>> f() async => new FixedPoint<int>(); //# 06: ok
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Future<FixedPoint<int>> f() async { return new FixedPoint<int>(); } //# 07: ok
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Future<FixedPoint<int>> x = (() async => new FixedPoint<int>())(); //# 08: runtime error
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// flatten(Divergent<int>) = Divergent<Divergent<int>>
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Divergent<Divergent<int>> x = await new Divergent<int>(); //# 09: runtime error
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Future<Divergent<Divergent<int>>> f() async => new Divergent<int>(); //# 10: ok
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Future<Divergent<Divergent<int>>> f() async { return new Divergent<int>(); } //# 11: ok
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Future<Divergent<Divergent<int>>> x = (() async => new Divergent<int>())(); //# 12: runtime error
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}
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main() {
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test();
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}
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