Laravel验证规则required_if另一个字段值在数组中，不起作用

namespace App\Rules;

use Illuminate\Contracts\Validation\Rule;

class InArray implements Rule
{
    protected $array;

    public function __construct($array)
    {
        $this->array = $array;
    }

    public function passes($attribute, $value)
    {
        return in_array($value, $this->array);
    }

    public function message()
    {
        return 'The selected :attribute is invalid.';
    }
}

use App\Rules\InArray;

$request->validate([
    'field1' => [
        'required_if:field2,' . implode(',', $array),
        new InArray($array)
    ],
]);