explicit signatures and default for integer literals

[Mirko Rahn]

>>> {-# OPTIONS -fglasgow-exts #-}
>>>
>>> import Data.Map
>>>
>>> class New a b where new :: a -> b
>>>
>>> instance Ord a => New [(a,b)] (Map a b) where new = fromList
>>>
>>> g :: Ord a => [a] -> Map a Int
>>> g xs = new $ zip xs [0..]

> Why is ghc unable the determine the type of the Literal 0 in the 
> definition of g?

Answer: Since somewhere an instance e.g. New [(a,Double)] (Map a Int) 
could be defined, leading to problems when threating 0 as (0::Int).

Thanks to private communication, Cheers,

-- 
-- Mirko Rahn -- Tel +49-721 608 7504 --
--- http://liinwww.ira.uka.de/~rahn/ ---