Replace HTraversable with TraversableB (from barbies)

[ocharles]

Fixes #403

[ocharles]

Open questions:

• Should we reexport FunctorB and TraversableB?

[jacobstanley]

• Should we reexport FunctorB and TraversableB?

I'm thinking yes, mostly because HTraversable is currently exposed.

[jacobstanley]

Suggested change

	, barbies
	, barbies >= 2.0 && < 2.1

(or whatever lower bound works)

[mitchellwrosen]

An update - I believe 2.0 is more or less the correct barbies lower bound (as Data.Functor.Barbie did not exist prior), but (I think?) it would require dropping support for GHC 8.0 and 8.2 due to this:

src/Data/Generics/GenericN.hs:40:1: error:
    • Kind signature on data type declaration has non-* return kind k
    • In the data family declaration for ‘Param’
   |
40 | data family Param (n :: Nat) (a :: k) :: k
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[mitchellwrosen]

Ping!

[jacobstanley]

it would require dropping support for GHC 8.0 and 8.2 due to this

That's a shame but I think it's probably ok.

[jacobstanley]

I found that the required classes used to be in Data.Barbie and were moved to Data.Functor.Barbie in barbie-2.0.0.0

I've put in a module Hedgehog.Internal.Barbie which hides the required CPP.