Modifying properties by reference should be forbidden for @immutable

[vudaltsov]

https://psalm.dev/r/772662e57b

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/772662e57b

<?php

declare(strict_types=1);

/**
 * @psalm-immutable
 */
class Obj
{
    public string $property = 'read-only value';
}

$obj = new Obj();
$property = &$obj->property;
$property = 'mutated value';

Psalm output (using commit 20e0047):

No issues!

[klimick]

Psalm throws UnsupportedPropertyReferenceUsage after #9769

[vudaltsov]

Cool, thanks!