enhanced enums - back from the dead?

Hi, as mentioned in [1], the work on enhanced enum stopped while ago as we have found some interoperability issues between generic enums and standard enum APIs such as EnumSet/EnumMap. Recently, we have discussed a possible approach that might get us out of the woods, which is described in greater details here: http://cr.openjdk.java.net/~mcimadamore/amber/enhanced-enums.html We have done some internal testing to convince ourselves that, from an operational perspective, where we end up is indeed good. Some external validation might also be very helpful, which is why we're also in the process of releasing the internal patch we have tested internally in the 'enhanced-enums' amber branch (we'll need to polish it a little :-)). Assuming that, usability-wise, our story ticks all the boxes, I think it might be worth discussing a few points: * Do we still like the features described in JEP 301, from an expressiveness point of view? * Both features described in JEP 301 require some sort of massaging. On the one hand sharper typing of enum constants has to take care of binary compatibility of enum constant subclasses into account (for this reason we redefine accessibility of said subclasses along with their binary names). On the other hand, with the newly proposed approach, generic enums also need some language aid (treatment of raw enum constants supertypes). Do we feel that the steps needed in order to accommodate these sharp edges are worth the increase in expressive power delivered by JEP 301? * Our proposed treatment for generic enums raises an additional, more philosophical, question: what are raw types *for* and how happy are we in seeing more of them (in the form of raw enum types)? Cheers Maurizio [1] - http://mail.openjdk.java.net/pipermail/amber-spec-experts/2017-May/000041.html