?string should return ReflectionUnionType instead of ReflectionType

[donjajo]

Description

The following code:

<?php

class A {
    protected ?string $foo = null;
}

$a = new A();
$reflection = new ReflectionProperty($a, 'foo');
var_dump($reflection->getType());

Resulted in this output:

object(ReflectionNamedType)#3 (0) {
}

But I expected this output instead:

object(ReflectionUnionType)#3 (0) {
}

?string should be a union type, since it also equates to null|string, which also returns a ReflectionNameType instead of ReflectionUnionType. But, if I change the type to null|array|string, this results to ReflectionUnionType

PHP Version

PHP 8.4.1-dev

Operating System

No response

[kallesommernielsen]

This is very unlikely to change anytime soon, and exists this way today because the nullable types syntax existed prior to union types.

Changing this will have BC implications, however if you are interested in creating an RFC to implement and change this, then head to the wiki: https://wiki.php.net/rfc