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

[Ashley Yakeley]

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