UnusedVariable reported when set in loop

[muzcb]

A variable set in a foreach loop gets falsely reported as unused.

<?php
class UnusedAfterForeach
{
    public function getLastNum(): int
    {
        foreach ([1] as $num) {
            $last = $num;
        }
        return $last;
    }
}

echo (new UnusedAfterForeach())->getLastNum();

ERROR: UnusedVariable - src\UnusedAfterForeach.php:7:13 - Variable $last is never referenced
            $last = $num;

https://psalm.dev/r/495531ea84

[muglug]

More real-worldish version: https://psalm.dev/r/ed40428e9c

Your example can be worked around by initialising $last to null before the loop: https://psalm.dev/r/9ee9d1366a