#10604: Make Generic1 kind polymorphic -------------------------------------+------------------------------------- Reporter: DerekElkins | Owner: ekmett Type: feature request | Status: new Priority: low | Milestone: Component: Core Libraries | Version: 7.10.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Old description:
It looks to me that the Generic1 class (and the Rep1 associated type) can immediately be generalized to forall k. k -> *. If k was instantiated to anything other than *, you wouldn't be able to make an instance for Par1, but then I don't think it would ever come up so that would be exactly the right behavior. This allows, in particular, DataKinds to be used as a parameter to instances of Generic1.
I don't know if this would affect deriving, but I wouldn't really expect it to.
New description: It looks to me that the `Generic1` class (and the `Rep1` associated type) can immediately be generalized to `forall k. k -> *`. If `k` was instantiated to anything other than `*`, you wouldn't be able to make an instance for `Par1`, but then I don't think it would ever come up so that would be exactly the right behavior. This allows, in particular, `DataKinds` to be used as a parameter to instances of `Generic1`. I don't know if this would affect deriving, but I wouldn't really expect it to. -- Comment (by simonpj): Happily, Andres Loh has agreed to take a lead in `Generics` and `DeriveAnyClass`, but only later this summer. Thanks Andres! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10604#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler