Simon Marlow wrote:
In response to this ticket: http://hackage.haskell.org/trac/ghc/ticket/5275 ... === Proposed API changes === 1. DEPRECATE mkTyCon... 2. Add mkTyCon3 :: String -> String -> String -> TyCon ...Most users can just derive Typeable, there's no need to use mkTyCon3. In due course we can rename mkTyCon3 back to mkTyCon.
Anecdotally, it seems to me that many, if not most, packages on Hackage that create Typeable instances do so using mkTyCon, not by deriving Typeable. There seems to be some standard boilerplate that spreads virally from one library to the next. Perhaps it would be worth checking to what extent mkTyCon is used on Hackage. If this is as widespread as I suspect, even a simple deprecation warning could have a cascading effect on typical output from cabal install. Thanks, Yitz