Re: cycles in class definitions

[Simon L Peyton Jones]

> > class Fallible m where
> >       fail_      :: String -> m a
> >       rethrow    :: Fallible n => m a -> n b
> 
> GHC 2.10 (solaris) complains about this:
> 
> >> Cycle.lhs:2: Cycle in class declarations ... `Fallible' Cycle.lhs:4
> 
> 
> Whereas Hugs (jan98) is fine with it.
> 
> I didn't see anything in the 1.4 report which forbids such declarations,
> and haven't found anything in the ghc docs. 
> 
> So, which system is doing the right thing? 

I think Hugs is.  I had better fix this.

Simon