Propsal: NoDatatypeContexts

Max Bolingbroke batterseapower at
Tue Jul 20 03:40:30 EDT 2010

On 19 July 2010 23:14, Thomas Schilling <nominolo at> 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.


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