Propsal: NoDatatypeContexts

[Max Bolingbroke]

On 19 July 2010 23:14, Thomas Schilling <nominolo at googlemail.com> wrote:
> I would be interested in a case where it actually *is* a good idea to
> use such contexts.

If you don't have kind signatures, you can use them as a hack to
change the inferred kind for an EmptyDataDecl

"""
-- a has kind *
data Foo a
"""

"""
class Stupid a where
  unused :: a ()

-- a has kind (* -> *)
data Stupid a => Foo a
"""

I think HList was using this kind of hack until recently.

Cheers,
Max