hphp/hack/test/typecheck/this_chain.php

   1 <?hh // strict
   2 /**
   3  * Copyright (c) 2014, Facebook, Inc.
   4  * All rights reserved.
   5  *
   6  * This source code is licensed under the BSD-style license found in the
   7  * LICENSE file in the "hack" directory of this source tree. An additional grant
   8  * of patent rights can be found in the PATENTS file in the same directory.
   9  *
  10  */
  11
  12 class Base {
  13   public function setA(): this { return $this; }
  14 }
  15
  16 class Child1 extends Base {}
  17 class Child2 extends Base {}
  18 class Child3 extends Base {}
  19 class Child4 extends Base {}
  20
  21 function foo(int $x): Base {
  22   switch ($x) {
  23     case 0:
  24       $thing = new Child1();
  25       break;
  26     case 1:
  27       $thing = new Child2();
  28       break;
  29     case 2:
  30       $thing = new Child3();
  31       break;
  32     default:
  33       $thing = new Child4();
  34       break;
  35   }
  36   return $thing->setA()->setA()->setA()->setA();
  37 }