#8813: further support deriving instances Typeable1, Typeable2, etc ----------------------------------------------+---------------------------- Reporter: maeder | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: Resolution: | 7.8.1-rc1 Operating System: Unknown/Multiple | Keywords: Type of failure: GHC rejects valid program | Architecture: Test Case: | Unknown/Multiple Blocking: | Difficulty: Unknown | Blocked By: | Related Tickets: ----------------------------------------------+---------------------------- Comment (by simonpj): Guys, lets all be polite! Christian, yes indeed one of the primary motivations for `-XConstraintKinds` was to allow "type" synonyms to include class constraints (and indeed all sorts of constraints). Pedro said "I couldn't find an acceptable solution. But, as I said before, I would very much welcome a better solution." Reid suggested one, perhaps one that Pedro thought of and discarded, perhaps not. It has the advantage that it might be a simple change to `Data.Typeable` making (deprecated) exports of `Typeable1`, `Typeable2` etc. Pedro: can you think of any problems with this? Thanks Reid. If someone would like to try it out and send a patch the validates, it might just make it into 7.8. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8813#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler