Breaks the TyCon/types loop and the types/Id loop.

\begin{code}
interface TyLoop where

import PreludePS(_PackedString)
import PreludeStdIO ( Maybe )
import Unique ( Unique )

import FieldLabel ( FieldLabel )
import Id      ( Id, GenId, StrictnessMark, mkTupleCon, mkDataCon,
		 isNullaryDataCon, dataConArgTys, idType )
import PprType ( specMaybeTysSuffix )
import Name    ( Name )
import TyCon   ( TyCon )
import TyVar   ( GenTyVar, TyVar )
import Type    ( splitSigmaTy, splitFunTy, GenType, Type )
import Usage   ( GenUsage )
import Class   ( Class, GenClass )
import TysPrim ( voidTy )

data GenId    ty
data GenType  tyvar uvar
data GenTyVar uvar
data GenClass tyvar uvar
data GenUsage u

type Type  = GenType (GenTyVar (GenUsage Unique)) Unique
type TyVar = GenTyVar (GenUsage Unique)
type Class = GenClass (GenTyVar (GenUsage Unique)) Unique
type Id	   = GenId (GenType (GenTyVar (GenUsage Unique)) Unique)

-- Needed in TyCon
mkTupleCon :: Int -> Id
isNullaryDataCon :: Id -> Bool
specMaybeTysSuffix :: [Maybe Type] -> _PackedString
idType :: Id -> Type
splitSigmaTy :: GenType t u -> ([t], [(Class,GenType t u)], GenType t u)
splitFunTy   :: GenType t u -> ([GenType t u], GenType t u)
instance Eq (GenClass a b)

-- Needed in Type
dataConArgTys :: Id -> [Type] -> [Type]
voidTy :: Type

-- Needed in TysWiredIn
data StrictnessMark = MarkedStrict | NotMarkedStrict
mkDataCon :: Name -> [StrictnessMark] -> [FieldLabel]
	  -> [TyVar] -> [(Class,Type)] -> [Type] -> TyCon
	  -> Id
\end{code}