ghc fails to find the right instance

[Claus Reinke]

'Integer -> a'  is more concrete, less general than 'i -> a',
so it matches fewer types.

'1 :: Num a => a' is more general than 'Integer'.

|    No instance for (More (t -> Integer))
|      arising from a use of `addd' at test.hs:19:17-22

if nothing forces the parameter (!) to be Integer, the
more concrete instance won't match. try type-annotating
the numeric literals.

claus