|  | // TODO(multitest): This was automatically migrated from a multitest and may | 
|  | // contain strange or dead code. | 
|  |  | 
|  | // @dart = 2.9 | 
|  |  | 
|  | // Copyright (c) 2015, 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. | 
|  |  | 
|  | // Verify semantics of the ?. operator when it is used to invoke a method. | 
|  |  | 
|  | import "package:expect/expect.dart"; | 
|  | import "conditional_access_helper.dart" as h; | 
|  |  | 
|  | bad() { | 
|  | Expect.fail('Should not be executed'); | 
|  | } | 
|  |  | 
|  | class B {} | 
|  |  | 
|  | class C extends B { | 
|  | f(callback()) => callback(); | 
|  | int g(int callback()) => callback(); | 
|  | static staticF(callback()) => callback(); | 
|  | static int staticG(int callback()) => callback(); | 
|  | } | 
|  |  | 
|  | C nullC() => null; | 
|  |  | 
|  | main() { | 
|  | // Make sure the "none" test fails if method invocation using "?." is not | 
|  | // implemented.  This makes status files easier to maintain. | 
|  | nullC()?.f(null); | 
|  |  | 
|  | // o?.m(...) is equivalent to ((x) => x == null ? null : x.m(...))(o). | 
|  |  | 
|  |  | 
|  |  | 
|  | // C?.m(...) is equivalent to C.m(...). | 
|  | Expect.equals(1, C?.staticF(() => 1)); | 
|  |  | 
|  |  | 
|  | // The static type of o?.m(...) is the same as the static type of | 
|  | // o.m(...). | 
|  |  | 
|  |  | 
|  |  | 
|  |  | 
|  |  | 
|  |  | 
|  |  | 
|  |  | 
|  |  | 
|  | // Let T be the static type of o and let y be a fresh variable of type T. | 
|  | // Exactly the same static warnings that would be caused by y.m(...) are also | 
|  | // generated in the case of o?.m(...). | 
|  |  | 
|  |  | 
|  |  | 
|  | // '?.' can't be used to access toplevel functions in libraries imported via | 
|  | // prefix. | 
|  |  | 
|  |  | 
|  | // Nor can it be used to access the toString method on the class Type. | 
|  |  | 
|  |  | 
|  | } |