#14190: Typeable imposes seemingly redundant constraints on polykinded instances -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler (Type | Version: 8.2.1 checker) | Resolution: | Keywords: Typeable Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): Regarding comment:7, I'm not sure how easy it would be to implement this. Goldfire will need to comment here, but it seems like this may be hard as there is nothing tying `k` back to `a`. One way of hacking around this might be to add `Typeable k` evidence to the solved dictionary cache every time we solve for `Typeable (a :: k)`. However, this would lead to the production of lots of redundant evidence and just feels terribly wrong. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14190#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler