#9858: Typeable instances should be kind-aware -------------------------------------+------------------------------------- Reporter: dreixel | Owner: dreixel 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 oerjan): Replying to [comment:58 goldfire]:
This defaulting to `*` is precisely what happens without `PolyKinds` on. So anyone not worried about kind variables won't need to.
Oh, so it is, on second testing. My first test (with my mock implementation, whose inferred types I think are "close enough" for the purpose) failed, but I only removed `PolyKinds` and must have left some other extension that implied it.
But I don't like this defaulting behavior if `PolyKinds` ''is'' on. If a user has specified `PolyKinds` and writes the code in comment:57, I would want an error to be reported. The choice of the kind variable here is potentially relevant to the programmer's desired behavior, and I think silently guessing a value is wrong here.
Good point, although I'm still wondering which option will break the least code... -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9858#comment:59> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler