hphp/hack/test/typecheck/constraint_gen_fail3.php

   1 <?hh // strict
   2 /**
   3  * Copyright (c) 2014, Facebook, Inc.
   4  * All rights reserved.
   5  *
   6  * This source code is licensed under the MIT license found in the
   7  * LICENSE file in the "hack" directory of this source tree.
   8  *
   9  *
  10  */
  11
  12 interface A {
  13   public function render(): string;
  14 }
  15
  16 class L<T as A> {
  17   private ?T $data = null;
  18
  19   public function set(T $x): void { $this->data = $x; }
  20   public function get(): ?T { return $this->data; }
  21 }
  22
  23 class U<T> extends L<A> {
  24   public function get(): ?T { return parent::get(); }
  25 }
  26
  27
  28