1--TEST--
2yield can be used without a value
3--FILE--
4<?php
5
6function recv() {
7    while (true) {
8        var_dump(yield);
9    }
10}
11
12$receiver = recv();
13var_dump($receiver->current());
14$receiver->send(1);
15var_dump($receiver->current());
16$receiver->send(2);
17var_dump($receiver->current());
18$receiver->send(3);
19
20?>
21--EXPECT--
22NULL
23int(1)
24NULL
25int(2)
26NULL
27int(3)
28