hphp/hack/test/typecheck/constmap.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 function covariance(ConstMap<arraykey, mixed> $x): void {}
  13 function test1(Map<string, int> $c): ConstMap<arraykey, mixed> {
  14   covariance($c);
  15   return $c;
  16 }
  17 function test2(ImmMap<string, int> $c): ConstMap<arraykey, mixed> {
  18   covariance($c);
  19   return $c;
  20 }
  21
  22 class C<Tv> {
  23   public function covariance(ConstMap<arraykey, Tv> $x): void {}
  24   public function test1<Tu as Tv>(Map<string, Tu> $c): ConstMap<arraykey, Tv> {
  25     $this->covariance($c);
  26     return $c;
  27   }
  28   public function test2<Tu as Tv>(
  29     ImmMap<string, Tu> $c
  30   ): ConstMap<arraykey, Tv> {
  31     $this->covariance($c);
  32     return $c;
  33   }
  34 }