[Haskell-cafe] Type synonym application
lemming at henning-thielemann.de
Mon Mar 19 12:58:38 EDT 2007
On Mon, 19 Mar 2007, Ian Lynagh wrote:
> On Sun, Mar 18, 2007 at 05:47:21PM +0000, C Rodrigues wrote:
> > Type synonyms aren't applied as I would expect during kind checking.
> > What's going on here?
> > type WithList a b = b [a]
> > type FooPair a b = (b, a -> b)
> > -- error: `WithList' is applied to too many type arguments
> > ints1 :: WithList Int FooPair [Int]
> > ints1 = (, id)
> That's caused by kind defaulting, as bulat said.
In Haskell 98 it is not allowed to define type synonymes in a partially
applied manner. That is, there is no alternative to
type WithList a b c = b [a] c
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