<?php

final class DemoFile
{
    public function run()
    {
        $vouchers[] = $voucher = new stdObject;
        $vouchers->test = 'test';
        
        return $vouchers;
    }
}

<?php

final class DemoFile
{
    public function run()
    {
        $voucher = new stdObject;
        $vouchers[] = $voucher;
        $voucher->test = 'test';
        
        return $vouchers;
    }
}