Google Summer of Code candidates should follow the general contribution guidelines before beginning work on an issue and submitting pull requests. Students interested in working on NIX as part of GSoC 2017 should read the guidelines described in the GSoC student guide regarding making first contact. They're quite useful for general open source contributions as well.
The GSoC programme encourages open communication and so do we. While directly contacting the mentors may get a response, please refrain from doing so unless discussing personal matters. For all topics regarding the project, issues, patches, preparing proposals, please use the discussion threads on Trellis (NIX Dataframe support, NIX filesystem backend), or comment directly on a relevant issue or pull request, whichever is more appropriate.
There is a #gnode IRC channel on Freenode which you may join for more casual discussions with the team.
Please keep discussion topics in their relevant venue. Thoughts and concerns regarding NIX should be discussed in GitHub issues. Project ideas should be discussed on Trellis. Less formal discussions can be had in the IRC chatroom. If you are new to IRC, this etiquette guide may be useful.