Alias weird 2

alias.php

<?php

use stdClass as Object;

$class1 = 'stdClass';
$class2 = 'Object';

var_dump(new stdClass());
var_dump(new Object());
var_dump(new $class1());
var_dump(new $class2());

/*
object(stdClass)#1 (0) {
}
object(stdClass)#1 (0) {
}
object(stdClass)#1 (0) {
}

Fatal error: Class 'Object' not found in test/index.php on line 11
*/