[Haskell-cafe] Re: ambiguous partially defined type problem

Brian Hulley brianh at metamilk.com
Fri Sep 15 10:53:03 EDT 2006

Maarten wrote:
> Only update (see code below) is a bit ugly (I have no idea why I need
> fixCastUpdate) 
>    update :: a -> (forall b. (ICustom b) => b -> b) -> a
>    update a f = f a

If you changed the type signature to:

    update :: a -> (a -> a) -> a

would the code compile without fixCastUpdate?

Regards, Brian.
Logic empowers us and Love gives us purpose.
Yet still phantoms restless for eras long past,
congealed in the present in unthought forms,
strive mightily unseen to destroy us.


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