|  | // 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. | 
|  | // @dart=2.9 | 
|  | /*@testedFeatures=inference*/ | 
|  | library test; | 
|  |  | 
|  | import 'dart:async'; | 
|  |  | 
|  | class MyFuture<T> implements Future<T> { | 
|  | MyFuture() {} | 
|  | MyFuture.value(T x) {} | 
|  | dynamic noSuchMethod(invocation) => null; | 
|  | MyFuture<S> then<S>(FutureOr<S> f(T x), {Function onError}) => null; | 
|  | } | 
|  |  | 
|  | void test() { | 
|  | Future f; | 
|  | Future<int> t1 = f. /*@ typeArgs=int* */ /*@target=Future.then*/ then( | 
|  | /*@ returnType=Future<int*>* */ (/*@ type=dynamic */ _) async => | 
|  | await new MyFuture<int>.value(3)); | 
|  | Future<int> t2 = f. /*@ typeArgs=int* */ /*@target=Future.then*/ then( | 
|  | /*@ returnType=Future<int*>* */ (/*@ type=dynamic */ _) async { | 
|  | return await new MyFuture<int>.value(3); | 
|  | }); | 
|  | Future<int> t3 = f. /*@ typeArgs=int* */ /*@target=Future.then*/ then( | 
|  | /*@ returnType=Future<int*>* */ (/*@ type=dynamic */ _) async => 3); | 
|  | Future<int> t4 = f. /*@ typeArgs=int* */ /*@target=Future.then*/ then( | 
|  | /*@ returnType=Future<int*>* */ (/*@ type=dynamic */ _) async { | 
|  | return 3; | 
|  | }); | 
|  | Future<int> t5 = f. /*@ typeArgs=int* */ /*@target=Future.then*/ then( | 
|  | /*@ returnType=MyFuture<int*>* */ (/*@ type=dynamic */ _) => | 
|  | new MyFuture<int>.value(3)); | 
|  | Future<int> t6 = f. /*@ typeArgs=int* */ /*@target=Future.then*/ then( | 
|  | /*@ returnType=MyFuture<int*>* */ (/*@ type=dynamic */ _) { | 
|  | return new MyFuture<int>.value(3); | 
|  | }); | 
|  | Future<int> t7 = f. /*@ typeArgs=int* */ /*@target=Future.then*/ then( | 
|  | /*@ returnType=Future<int*>* */ (/*@ type=dynamic */ _) async => | 
|  | new MyFuture<int>.value(3)); | 
|  | Future<int> t8 = f. /*@ typeArgs=int* */ /*@target=Future.then*/ then( | 
|  | /*@ returnType=Future<int*>* */ (/*@ type=dynamic */ _) async { | 
|  | return new MyFuture<int>.value(3); | 
|  | }); | 
|  | } | 
|  |  | 
|  | main() {} |