Errors with nested case classes

[brinklec]

As reported on gitter, derivation appears to fail across the board for nested case classes, even with explicit derive calls on the inner ones.

csvTest1.txt
csvTest2.txt

Above are two differently constructed minimal examples.

I don't mind doing explicit derivation on the inner ones, though of course it would be nice if that were not needed.

I don't actually need fully general nesting, either.

I'm using nested case classes for stronger typing on database records. Each inner case class only takes a single argument with a type built into the language. An outer one typically has many arguments, each of which is one of the inner ones just described.