Incorrect behavior of PreparedValueToEarlyReturnRector

[staabm]

Bug Report

Subject	Details
Rector version	last dev-main
Installed as	composer dependency

Minimal PHP Code Causing Issue

See https://getrector.com/demo/776ea60b-3f0c-4c6f-94b6-ffa54ce1005b

<?php

function articelnameWithFootnotes(clxArtikel $artikel, $showZusatz = true): string
    {
        $return = HtmlHelper::escape_htmlspecial($artikel->getName());
        if ($showZusatz) {
            $return = HtmlHelper::escape_htmlspecial($artikel->getName().' '.$artikel->getZusatz());
        }

        if ('' != $artikel->rechtstext) {
            $footnote = Cmsfootnote::fetchOrCreate($artikel->rechtstext, '**');
            $return .= $footnote->renderReference();
        }

        return $return;
    }

Responsible rules

• PreparedValueToEarlyReturnRector

Expected Behavior

after transformation phpstan reports

Undefined variable: $return

because the code after rector processed it, is not euqivalent to the initial logic

my guess is that rector does not realize, that there is a .= assignment