#9043: Add missing type class instances for data types in GHC.Generics -------------------------------------+------------------------------------ Reporter: ocharles | Owner: dreixel Type: feature request | Status: patch Priority: normal | Milestone: Component: libraries/base | Version: 7.8.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by dreixel): I've had a look at this, and all seems fine to me. One caveat however: {{{ instance (Data p, Data (f p), Typeable c, Typeable i, Typeable f) => Data (M1 i c f p) where }}} This `Typeable c` constraint will require changing the generation of `Generic` instances in GHC, because these `c`s are compiler-generated empty datatypes, which currently do not derive `Typeable`. Simon: what's the best way to do this? We need `Typeable` instances for the stuff generated by `mkBindsMetaD` in `TcGenGenerics`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9043#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler