#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:27 crockeea]:
To echo @dreixel: What exactly *is* SPJ's suggestion? Is it to not *automatically* derive `Typeable` instances for poly-kinded type constructors, or is to disallow standalone-derived instances as well?
Presumably it would be safe to allow a *single* standalone derivation in the same module that defines the type, as long as it's of actual monomorphic kind. That way, at least `Proxy` could still have a `* -> *` instance, which might be the one that is used the most in practice? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9858#comment:28 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler