| // 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() { |
| var /*@ type=Future<double*>* */ f = |
| foo(). /*@ typeArgs=double* */ /*@target=Future.then*/ then( |
| /*@ returnType=double* */ (/*@ type=dynamic */ _) => 2.3); |
| Future<int> f2 = /*error:INVALID_ASSIGNMENT*/ f; |
| |
| // The unnecessary cast is to illustrate that we inferred <double> for |
| // the generic type args, even though we had a return type context. |
| Future<num> f3 = /*info:UNNECESSARY_CAST*/ foo() |
| . /*@ typeArgs=double* */ /*@target=Future.then*/ then( |
| /*@ returnType=double* */ (/*@ type=dynamic */ _) => 2.3) |
| as Future<double>; |
| } |
| |
| Future foo() => new Future<int>.value(1); |
| |
| main() {} |