As far as I can tell in the latin part of Europe I think it's well understood that if you invite people to a restaurant for dinner it means that you will be paying (especially if the word invite is used).
In the UK it depends on the background of people, and language would also make a difference.
"Do you all want to grab some dinner" is different to "I'd like to invite you all out to dinner"
>But that's still no expected from the host unless explicitly verbalized with the invitation.
In Europe there would definitely be an expectation that alcohol would be provided (although perhaps not all of the alcohol depending on various factors). It would also be expected that guests bring a bottle of wine or flowers or something to that effect. That small gift should be separate to any alcohol brought for the purposes of consumption on the evening.