Hi,

I've coded 2 services:

1. The concrete service

<service id="just.simple.service" parent="parent.abstract" public="false" class="%parameter.just.simple.service.class%">
    <argument type="service" id="blabla" />
</service>

1. The exposed service

<service id="just.service" alias="just.simple.service">
    <tag name="find.by.this.tag" />
</service>

When I try to get the services with the tag "find.by.this.tag" in a CompilerPass it returns a empty array.

$services = $container->findTaggedServiceIds('find.by.this.tag');

And the reason is because it iterates over ContainerBuilder::getDefinitions() and it ignores the $aliasDefinitions.