#9725: Constraint deduction failure -------------------------------------+------------------------------------- Reporter: heisenbug | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 (Type checker) | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: GHC | Related Tickets: rejects valid program | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by heisenbug): Replying to [comment:15 goldfire]:
After some struggle, I came up with a working construction, attached. Bonus points if you can make it prettier and/or bind the scoped type variables without adding proxies.
Thanks, Richard, this is very cool. It will take a while for me to analyse what exactly you are doing. I attached a version based on your workaround that makes the kind `En` a bit more interesting. I believe I can now transfer this into my real code :-) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9725#comment:16 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler