3 * Copyright (c) 2014, Facebook, Inc.
6 * This source code is licensed under the MIT license found in the
7 * LICENSE file in the "hack" directory of this source tree.
12 interface FormatString
<T
> { }
15 public function format_s(string $s) : string;
18 function f(FormatString
<Dummy
> $x, mixed...$args) : void
{
21 function _(string $x) : void
{