Description:
------------
Without opcache this script prints 4. With opcache, on the first request to this script you get 4 as well. On the 2nd request when you hit the opcached version you get a nested array. Reproducable from cli with:

opcache.enable_cli=1
opcache.file_cache=/var/tmp
opcache.file_cache_only=1

It is fine in 7.0, so it is something we broke in 7.1

Test script:
---------------
<?php
class Schema_Base {
    public function addField($typeclass, array $params = null) {
        $field = new $typeclass($params);
        return $field;
    }
}

class Field_Base {
    public function __construct(array $params = null) {
        if (! is_array($params)) {
            $params = (array) $params;
        }
        call_user_func_array(array($this, 'acceptParams'), $params);
    }
}

class Field_Integer extends Field_Base {
    protected function acceptParams($bytes = 4) {
        echo print_r($bytes, true);
    }
}

try {
    $schema = new Schema_Base;
    $schema->addField('Field_Integer');
} catch (Throwable $ex) {
    echo "CAUGHT EXCEPTION";
    echo (string)$ex;
}


Expected result:
----------------
4

Actual result:
--------------
Array
(
    [0] => Array
 *RECURSION*
)