standalone deriving Typeable shouldn't need data constructors in scope?
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?
Trac metadata
Trac field | Value |
---|---|
Version | 6.9 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | Unknown |
Architecture | Unknown |