--TEST--
yield can be used without a value
--FILE--
<?php
function recv() {
while (true) {
var_dump(yield);
}
}
$receiver = recv();
var_dump($receiver->current());
$receiver->send(1);
var_dump($receiver->current());
$receiver->send(2);
var_dump($receiver->current());
$receiver->send(3);
?>
--EXPECT--
NULL
int(1)
NULL
int(2)
NULL
int(3)