hphp/hack/test/typecheck/constraint_generic.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 B implements A {
  17   public function render(): string { return 'foo'; }
  18 }
  19
  20 function toto(A $x): void {
  21 }
  22
  23
  24 function foo<T as A>(Vector<T> $x): Vector<T> {
  25   $x[0]->render();
  26   toto($x[0]);
  27   return $x;
  28 }
  29
  30 function test_vector(): void {
  31   $x = foo(Vector {new B()});
  32 }
  33
  34 function foo2<T as A>(T $x): T {
  35   $x->render();
  36   return $x;
  37 }
  38
  39
  40 class X {
  41
  42   public function foo<T as A>(T $x): T {
  43     $x->render();
  44     return $x;
  45   }
  46 }
  47
  48
  49 class Y extends X implements A {
  50
  51   public function test(): Y {
  52     return $this->foo($this);
  53   }
  54
  55   public function render(): string {
  56     return '0';
  57   }
  58 }
  59
  60 function test(): Vector<B> {
  61   $x = new B();
  62   return foo(Vector {});
  63 }
  64
  65
  66 class L<T as A> {
  67   private ?T $data = null;
  68
  69   public function set(T $x): void { $this->data = $x; }
  70   public function get(): ?T { return $this->data; }
  71 }
  72
  73 function test2(): void {
  74   $x = new L();
  75   $x->set(new B());
  76 }
  77
  78 class U<T as A> extends L<T> {
  79   public function get(): ?T { return parent::get(); }
  80 }
  81
  82 function test3(): void {
  83   $x = new U();
  84 }
  85
  86 function test4<T1, T2, T3 as KeyedIterable<T1, T2>>(T3 $x): void {
  87   foreach($x as $k => $v) {
  88     $k; $v;
  89   }
  90 }
  91
  92 function test5<T as ?int>(T $x): T {
  93   return $x;
  94 }