There isn't one. 7nm Ryzen 2 will sample this year with volume production late this year for delivery in 2019. As 7nm is a brand new process, it's going to depend on how well it goes.
It is a bit confusing. Ryzen (Summit Ridge, Zen) and Ryzen 2 (Pinnacle Ridge, Zen+) are both original Zen processors. Not to be confused with Zen 2 which will be launching sometime in 2019.
Zen+ is not Ryzen 2 but is 2nd Gen Ryzen. Zen 2 as many actually call it Ryzen 2 is not officially named yet and I don't know if anyone knows if it will be a Named Ryzen 2 1xxx or if it will be just Ryzen 3xxx. It is as you said confusing. This is all something you of course already said. I just wanted to add that the Zen + while being a continuation of the first Ryzen processor is a 2nd generation of that and includes a die shrink and feature improvements as well, that does distinguish a bit from the original release. It seems to be redundant I now to keep repeating this but, obvious it isn't clear still for so many.
I highly doubt Zen 2 will be called Ryzen 2, as that would be far to similar to Zen+ and 2nd generation Ryzen (Ryzen 2). Most likely, Zen 2 will be 3rd generation ryzen (or ryzen 3 if you will).
