Description:
------------
> Note that **mysqli_fetch_object()** sets the properties of the object before calling the object constructor.
>
> --- https://secure.php.net/mysqli-result.fetch-object

This is how it is described in the manual and how it worked in <7.0.6 but the new patch release introduced a serious BC in this regard.

I know that the way the method works is debatable and is being debated in internals, however, breaking this behavior in a patch release is out of question.

Test script:
---------------
final class Test {
    public $x;
    protected $y;
    private $z;
    public function __construct() {
        var_dump($this->x, $this->y, $this->z);
    }
}

$c = new mysqli();
$c->real_connect();
$c->select_db('test');
$r = $c->query('SELECT 21 AS `x`, 42 AS `y`, 84 AS `z`');
while (($o = $r->fetch_object(Test::class))) {
    var_dump($o);
}
$r->close();
$c->close();

Expected result:
----------------
string(2) "21"
string(2) "42"
string(2) "84"
object(Test)#3 (3) {
  ["x"]=>
  string(2) "21"
  ["y":protected]=>
  string(2) "42"
  ["z":"Test":private]=>
  string(2) "84"
}

Actual result:
--------------
NULL
NULL
NULL
object(Test)#3 (3) {
  ["x"]=>
  string(2) "21"
  ["y":protected]=>
  string(2) "42"
  ["z":"Test":private]=>
  string(2) "84"
}