#2433: standalone deriving Typeable shouldn't need data constructors in scope?
------------------------+---------------------------------------------------
Reporter: claus | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 6.9 | Severity: normal
Keywords: | Testcase:
Architecture: Unknown | Os: Unknown
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customary artificial example:
{{{
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE DeriveDataTypeable #-}
import Data.Typeable(Typeable1)
import qualified Prelude()
import Prelude(Maybe)
deriving instance Typeable1 Maybe
}}}
`GHCi, version 6.9.20080709`:
{{{
DTR.hs:8:0:
The data constructors of `Maybe' are not all in scope
so you cannot derive an instance for it
In the stand-alone deriving instance for `Typeable1 Maybe'
Failed, modules loaded: none.
}}}
Does `Typeable` really need access to the '''data''' constructors?
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2433>
GHC <http://www.haskell.org/ghc/>
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