[Hugs-users] Re: "Duplicate instance declarations"

Bulat Ziganshin wrote:

Hello all

why the folowing is not allowed even with all extensions enabled both in Hugs and GHC?

class BufStream h where

class CharStream h where instance (CharStream h) => BufStream h where

class MemoryStream h where instance (MemoryStream h) => BufStream h where

Try this: class (BufStream h) => CharStream h where class (BufStream h) => MemoryStream h where