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>
89 lines
2.3 KiB
Dart
89 lines
2.3 KiB
Dart
// Copyright (c) 2017, 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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// This test verifies that for a top level async function, the following three
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// types are all appropriately matched:
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// - The static return type
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// - The return type of reified runtime type of a tearoff of the function or
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// method
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// - The reified type of the future returned by the function or method
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//
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// Specific attention is paid to the following conditions:
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// - The static return type is determined by type inference
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// - The static return type is `dynamic`
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// - The function or method immediately returns a value or future with a
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// different type (possibly using `=>` syntax)
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import 'dart:async';
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import 'package:expect/expect.dart';
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class A {}
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class B extends A {}
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Future quick() async {}
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Future<B> futureB() => new Future<B>.value(new B());
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f_inferred() async {
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await quick();
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return new B();
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}
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dynamic f_dynamic() async {
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await quick();
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return new B();
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}
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Future<A> f_A() async {
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await quick();
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return new B();
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}
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Future<A> f_immediateReturn_B() async {
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return new B();
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}
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Future<A> f_immediateReturn_FutureB() async {
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return futureB();
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}
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Future<A> f_expressionSyntax_B() async => new B();
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Future<A> f_expressionSyntax_FutureB() async => futureB();
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// Not executed
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void checkStaticTypes() {
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// Check that f_inferred's static return type is `dynamic`, by verifying that
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// no error occurs if we try to call `foo` on its return value.
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f_inferred().foo();
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}
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void checkDynamic(dynamic tearoff) {
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Expect.isTrue(tearoff is dynamic Function());
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Expect.isFalse(tearoff is Future<dynamic> Function());
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dynamic f = tearoff();
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Expect.isTrue(f is Future<dynamic>);
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Expect.isFalse(f is Future<A>);
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}
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void checkFutureA(dynamic tearoff) {
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Expect.isTrue(tearoff is Future<A> Function());
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Expect.isFalse(tearoff is Future<B> Function());
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dynamic f = tearoff();
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Expect.isTrue(f is Future<A>);
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Expect.isFalse(f is Future<B>);
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}
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main() {
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checkDynamic(f_inferred);
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checkDynamic(f_dynamic);
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checkFutureA(f_A);
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checkFutureA(f_immediateReturn_B);
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checkFutureA(f_immediateReturn_FutureB);
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checkFutureA(f_expressionSyntax_B);
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checkFutureA(f_expressionSyntax_FutureB);
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}
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