Method demo

examples/demo.php:753–773

()

class ForeachByReferenceDemo
{
    public function demo(): void
    {
        /** @var list<Pen> $pens */
        $pens = getUnknownValue();

        // By-reference foreach: $pen resolves to element type (Pen)
        // and is not flagged as undefined or unused.
        foreach ($pens as &$pen) {
            $pen->write();                        // Pen from list<Pen>
            $pen = new Pen();                     // reassignment through reference
        }
        unset($pen);

        // Key-value with by-reference value
        /** @var array<string, Pen> $named */
        $named = getUnknownValue();
        foreach ($named as $key => &$tool) {
            $tool->color();                       // Pen from array<string, Pen>
        }
        unset($tool);
    }
}