hphp/hack/test/typecheck/abstract_implement2.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 // Allow delayed implementation for abstract classes
  13
  14 interface IFace<T> {
  15   public function foo(): T;
  16 }
  17
  18 abstract class AClass<T> implements IFace<T> {}
  19
  20 class BClass extends AClass<bool> {
  21   public function foo(): int {
  22     return $this->foo();
  23   }
  24 }