"Brian Smith"
Basically, the syntax for instances and derived instances would be identical, but derived instances would just omit the "where" clause, while non-derived instances would need the "where" clause.
This is a really _bad_ idea for readability. In a year's time, when this discussion is forgotten, who would be able to tell at a glance the deep and real semantic difference between the following two instance decls? instance Num (Bar z) where and instance Num (Bar z) The former declares that _no_ methods are defined (except for defaults), and the latter, with your proposal, that _all_ methods are defined. The real killer is that both of these decls are already valid in Haskell'98, but they mean the _same_ thing (the former, if you were wondering). This is a sure recipe for introducing new and subtle bugs into existing bug-free programs. Regards, Malcolm