symfony3.x - How to figure out which services are being called in Symfony 3.3 -

i upgraded symfony 3.2.4 3.3.8 use automatic service configuration. unfortunately, broke in configuration , guard implementation isn't working.

it seems service have set implement guard interface not being used , default implementation being used instead, i'm unsure how confirm or deny suspicion.

can give me guidance on how go determining whether service being called once registered? i'm pretty new symfony , find profiler overwhelming , confusing.

thanks in advance