postponing discussion on exceptions and deepSeq

[Ross Paterson]

On Tue, Apr 11, 2006 at 09:54:12PM -0400, Robert Dockins wrote:
> An additional issue is the following instance declarations, which require 
> undecidable instances under GHC:
> 
> Eq (s a) => Eq (Rev s a)
> (Sequence s, Read (s a)) => Read (Rev s a)
> (Sequence s, Show (s a)) => Show (Rev s a)

These are accepted by GHC 6.5, under a relaxed termination condition
that is a candidate for Haskell':

http://www.haskell.org/ghc/dist/current/docs/users_guide/type-extensions.html#instance-rules