Updated Drupal to 8.6. This goes with the following updates because it's possible...

[yaffs-website] / vendor / symfony / dependency-injection / Tests / Fixtures / xml / services_instanceof.xml

<?xml version="1.0" encoding="utf-8"?>
<container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
    <services>
        <instanceof id="Symfony\Component\DependencyInjection\Tests\Fixtures\BarInterface" lazy="true" autowire="true">
            <tag name="foo" />
            <tag name="bar" />
        </instanceof>

        <service id="Symfony\Component\DependencyInjection\Tests\Fixtures\Bar" class="Symfony\Component\DependencyInjection\Tests\Fixtures\Bar" />
        <service id="Symfony\Component\DependencyInjection\Tests\Fixtures\BarInterface" alias="Symfony\Component\DependencyInjection\Tests\Fixtures\Bar" />
    </services>
</container>