import Name
import NameSet
import VarEnv
import Name
import NameSet
import VarEnv
import PrelNames
import TysWiredIn
import BasicTypes
import PrelNames
import TysWiredIn
import BasicTypes
import Outputable
import FastString
import Outputable
import FastString
import Data.IORef
\end{code}
import Data.IORef
\end{code}