Hi all,
I encountered a problem when trying to

> derive makeBinary ''DiffTime

with help of derive package. The error was:

Not in scope: data constructor `MkDiffTime'

Which makes a sense, since it's not exported in Data.Time.Clock.
I bypassed the problem (yes, I'm too lazy to write instances by hands) with

> instance Binary UTCTime where
> put = putGeneric
> get = getGeneric

But it must be less efficient (and more verbose) than compile-time deriving.
If there was such a module like Data.Time.Clock.Internal, I could import it to get hidden constructors (and maybe I'll have to fork the library for this purpose).

OTOH, is it possible to change the derive TH function so it can bypass module encapsulation mechanism and access un-exported things?