#7704: Phantom types break new polykind Typeable with either StandaloneDeriving or AutoDeriveTypeable -----------------------------+---------------------------------------------- Reporter: nwf | Owner: dreixel Type: bug | Status: new Priority: normal | Component: Compiler Version: 7.7 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- Comment(by monoidal): In fact the "deriving (Typeable)" clause does not work either: {{{ {-# LANGUAGE DeriveDataTypeable, PolyKinds #-} import Data.Typeable newtype Tagged s b = Tagged { unTagged :: b } deriving (Typeable) k :: Typeable u => u -> Int k _ = 0 m = k (Tagged 0 :: Tagged Int Int) }}} (The code compiles without PolyKinds.) -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7704#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler