hphp/hack/test/typecheck/iface_require_covariant.php

   1 <?hh // strict
   2
   3 interface II {}
   4 interface JJ {}
   5
   6 class Super<+T> {}
   7
   8 interface Foo {
   9   require extends Super<II>;
  10 }
  11
  12 interface Bar {
  13   require extends Super<JJ>;
  14 }
  15
  16 interface Baz extends Foo, Bar {}
  17
  18 class KK implements II, JJ {}
  19
  20 class Qux extends Super<KK> implements Baz {}