Description:
------------
Argument unpacking works in constructors for user-defined classes:


class Foo {
	public function __construct($x) {
		echo $x;
	}
}

$f = ['Foo'];

$foo = new Foo(...$f);


Successfully prints "Foo" as the argument has been unpacked and passed into the constructor correctly.


However, inexplicably, it does not work for internal classes:



class Foo {
	public function __construct($x) {
		echo $x;
	}
}

$f = ['Foo'];
$reflect = new ReflectionClass(...$f);


Warning: ReflectionClass::__construct() expects exactly 1 parameter, 0 given in $file on line $line



In other cases it creates an exception:


$f = ['Foo'];
$dir = new DirectoryIterator(...$f);


Fatal error: Uncaught exception 'UnexpectedValueException' with message 'DirectoryIterator::__construct() expects exactly 1 parameter, 0 given' in $file

Test script:
---------------
class Foo {
	public function __construct($x) {
		echo $x;
	}
}

$f = ['Foo'];

$foo = new Foo(...$f);
$reflect = new ReflectionClass(...$f);
$dir = new DirectoryIterator(...$f);

Expected result:
----------------
Internal classes get constructed successfully

Actual result:
--------------
Internal classes either throw a warning or an exception