ghc expects that I use all type variables in a multi-paramter type class.
It seems to me that this makes no sense.
e.g.: a Dictionary class with 'key' as the type of keys in 'dict' and 'dat' as
the type of information associated with a key.
> class (Eq key, Ord key) => Dictionary dict key dat where
...
delete :: key -> dict -> dict
...
Obviously I need only 'key' and 'dict' in this operation. ghc wants to get the
'dat' in the type signature, too.
Is there any reason for this restriction?
Martin Stein
