TypeFamilies vs. FunctionalDependencies & type-level recursion

[Simon Peyton-Jones]

| One thing you could do to help in this specific case would be to use a
| different M1 tag--e.g., M1 S ... for selectors and M1 NS ... for
| fields without selectors (or K1 NS).  I presume you've already
| considered this and/or it's too late to make such a change.  (Or to
| move the distinction up to the constructor with two different
| constructor tags, CR and CN for record and no-record.)

I don't think it's too late to make a change.  The stuff has only just gone in, so it's still very malleable.  There may be other considerations, but legacy code isn't one of them!

Simon