hphp/hack/test/typecheck/await_preserves_nullability.php

   1 <?hh // partial
   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 Foo<T> {
  13   public async function print_if_possible(
  14     ?Awaitable<T> $blah,
  15   ): Awaitable<void> {
  16     $x = await $blah;
  17     $this->doer($x);
  18   }
  19
  20   private function doer(T $item): void {
  21     if ($item) {
  22       print $item;
  23     }
  24   }
  25 }