On Wed, Oct 3, 2012 at 1:01 PM, Simon Peyton-Jones <simonpj@microsoft.com> wrote:

* If we do make Typeable instances by default, there are two paths
   Plan A (easy): make GHC derive Typeable for everything, deprecate
            all uses of 'deriving Typeable'.  Small downside: some programs
            that are currently rejected will be accepted.