#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 Ptharien's Flame): If I may interject from the outside (so to speak), I think the best way to explain Simon's proposition (1) is in terms of parametricity, in a manner akin to the widely-expounded-upon use of monadic effects in Haskell. Adding a `Typeable` constraint is just like surrounding a type with `IO`: it allows more operations, while simultaneously marking the code as not- quite-pure in a specific way. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9858#comment:23 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler