Method demo

examples/demo.php:861–873

()

class SpreadOperatorDemo
{
    public function demo(): void
    {
        /** @var list<Pen> */
        $penList = [];
        /** @var list<Pencil> */
        $pencilList = [];

        $allPens = [...$penList];
        $allPens[0]->write();                     // resolves Pen from spread

        $everything = [...$penList, ...$pencilList];
        $everything[0]->label();                  // union: Pen|Pencil from multiple spreads
    }
}