Abstractly my main concern is that we've made a change (implicitly deriving Typeable everywhere) for the wrong reasons, and concretely my
#9858: Typeable instances should be kind-aware -------------------------------------+------------------------------------- Reporter: dreixel | Owner: Type: bug | Status: new Priority: highest | Milestone: 7.10.1 Component: Compiler | Version: 7.9 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by hvr): Replying to [comment:64 rwbarton]: main fear, given the timing of this change, is that we'll find the new approach is untenable for some reason or other and be forced back into a world in which explicit deriving Typeable is required. Does artificially keeping require to explicitly derive `Typeable` during the 7.10 cycle actually help us identifying issues, rather than just releasing this into the wild with 7.10 and gather real-world data during 7.10's life-cycle? Fwiw, IIRC we wanted to turn on `AutoDeriveTypeable` by default anyway sooner or later. So this change just accomplishes that by a different mechanism, but the outcome is the same IMO. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9858#comment:66 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler