false-positive `UnusedParam` when variables are used in by-ref assignment.

[azjezz]

Example: https://psalm.dev/r/9f69003dae

Expected: no issues about unused parameters.

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/9f69003dae

<?php

function s(object $r, string $f): void {
    $r->prop = &$f;
}

Psalm output (using commit cdceda0):

INFO: UnusedParam - 3:30 - Param f is never referenced in this method

INFO: UnusedParam - 3:19 - Param r is never referenced in this method

[azjezz]

It also seems that lhs of assignment by ref is never analyzed in psalm: https://psalm.dev/r/2616ad73f8

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/2616ad73f8

<?php

class User {}

function s(User $r, string $f): void {
    $r->prop = $f;
}

function p(User $r, string $f): void {
    $r->prop = &$f;
}

Psalm output (using commit cdceda0):

ERROR: UndefinedPropertyAssignment - 6:5 - Instance property User::$prop is not defined

INFO: UnusedParam - 9:28 - Param f is never referenced in this method

INFO: UnusedParam - 9:17 - Param r is never referenced in this method