hphp/hack/test/typecheck/super_constraint_2.php

   1 <?hh // strict
   2 class C123<+T> {
   3   private T $x;
   4   public function __construct(T $x) {
   5     $this->x = $x;
   6   }
   7   public function get(): T {
   8     return $this->x;
   9   }
  10   public function foo<Tu super T>(Tu $x, bool $b): Tu {
  11     if ($b) {
  12       return $this->x;
  13     } else {
  14       return $x;
  15     }
  16   }
  17 }
  18 class FooBase123 {}
  19 class Foo123 extends FooBase123 {}
  20 class FooDerived123 extends Foo123 {}
  21 class Woo {
  22   public function test1(
  23     C123<Foo123> $c,
  24     FooDerived123 $x,
  25     bool $b,
  26   ): FooDerived123 {
  27     return $c->foo($x, $b);
  28   }
  29 }