#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 rwbarton): Christian: actually that does work. That seems like a decent argument to include these type synonyms for backwards-compatibility purposes. (As kosmikus notes, they're still not 100% backwards compatible. For example, `Typeable` still doesn't fix the kind of its argument, which could matter in a module with `PolyKinds`; and since `TypeableN` is now a type synonym it can't be the argument to another type constructor (with `ConstraintKinds`). But those are both fairly obscure cases.) I fully agree though that the type synonyms should be marked as deprecated. `TypeableN` is a hack that served its purpose; now we can express our programs better using orthogonal features (polykinded types and kind signatures). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8813#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler