patch applied (ghc): isDataTyCon should be False for all type families, even data type families

[Manuel M T Chakravarty]

Simon,

> I think we are agreed that you hold the token on this, and on
http://hackage.haskell.org/trac/ghc/ticket/1331

Done.

> - add words to Section 4 of this same page, saying that it's a draft
user-manual entry

Done.

I still have to update the wiki docs and modify the manual as agreed. 
After that I'll change tcLookupFamInst as agreed (but that won't be today).

Manuel

> | -----Original Message-----
> | From: cvs-ghc-bounces at haskell.org [mailto:cvs-ghc-bounces at haskell.org] On Behalf Of Simon Peyton-Jones
> | Sent: 07 May 2007 11:44
> | To: Manuel M T Chakravarty
> | Cc: cvs-ghc at haskell.org
> | Subject: RE: patch applied (ghc): isDataTyCon should be False for all type families, even data type
> | families
> |
> | | "isAlgTyCon" doesn't do).  Roman, raised the question of whether we
> | | actually would want to permit newtype instances for data families (or in
> | | other words whether it makes sense to distinguish between data families
> | | and newtype families at all - it surely makes sense to distinguish
> | | between data instances and newtype instances, though).  What do you
> | | think?
> |
> | Indeed!  It makes no sense to have newtype families.  Let's just have
> |
> |         data family T ...
> |         type family T ...
> |
> | but not
> |
> |         newtype family ...
> |
> | For a data family T, you can say
> |
> |         data instance T ...
> | or
> |         newtype instance T...
> |
> | Will you do this or shall I?  We need to write the user manual stuff too.
> |
> | Simon