Status of Haskell'?

[Ben Millwood]

On Tue, Nov 27, 2012 at 5:35 PM, Ian Lynagh <igloo at earth.li> wrote:
> [...] adding DeriveDataTypeable
> hopefully wouldn't be too controversial [...]

This is a little tricky since the Data class itself makes (essential,
I think) use of Rank2Types. Typeable ought to be fine, but it might be
wise to see what GHC decides to do on that front, first, e.g. whether
it's going to autoderive all instances or forbid user instances or
anything else similarly bold.