I suggest doing a major release of transformers at the same time as the next major GHC release, with Data.Functor.Identity removed and added to
#9664: Add identity functor to base -------------------------------------+------------------------------------- Reporter: hvr | Owner: ekmett Type: task | Status: new Priority: normal | Milestone: 7.10.1 Component: Core | Version: Libraries | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Easy (less than 1 Unknown/Multiple | hour) Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by hvr): Replying to [comment:1 ross]: base. This version would depend on the new version of base to force an upgrade. Terrific! I'll draft a `transformers`-patch in our locally forked repo over at http://git.haskell.org/packages/transformers.git and migrate `Data.Functor.Identity` into GHC HEAD's `base` so we can start using that in GHC HEAD. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9664#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler