-- others:
import TysWiredIn ( nilDataCon, charDataCon, charTy )
import Var ( TyVar )
-import DataCon ( DataCon, dataConTyCon )
-import Maybes ( maybeToBool )
+import DataCon ( DataCon )
import Outputable
-import TyCon ( maybeTyConSingleCon )
import Type ( Type )
\end{code}