Things which are ubiquitous in the GHC compiler.

\begin{code}
interface Ubiq where

--import PreludePS(_PackedString)
import FastString(FastString)

import Bag		( Bag )
import BinderInfo	( BinderInfo )
import CgBindery	( CgIdInfo )
import CharSeq		( CSeq )
import CLabel		( CLabel )
import Class		( GenClass, GenClassOp, Class(..), ClassOp )
import ClosureInfo	( ClosureInfo, LambdaFormInfo )
import CmdLineOpts	( SimplifierSwitch, SwitchResult )
import CoreSyn		( GenCoreArg, GenCoreBinder, GenCoreBinding, GenCoreExpr,
			  GenCoreCaseAlts, GenCoreCaseDefault, Coercion
			)
import CoreUnfold	( Unfolding, UnfoldingGuidance )
import CostCentre	( CostCentre )
import FieldLabel	( FieldLabel )
import FiniteMap	( FiniteMap )
import HeapOffs		( HeapOffset )
import HsPat		( OutPat )
import HsPragmas	( ClassOpPragmas, ClassPragmas, DataPragmas, GenPragmas, InstancePragmas )
import Id		( StrictnessMark, GenId, Id(..) )
import IdInfo		( IdInfo, ArityInfo, DeforestInfo, StrictnessInfo, UpdateInfo )
import Demand		( Demand )
import Kind		( Kind )
import Literal		( Literal )
import MachRegs		( Reg )
import Maybes		( MaybeErr )
import MatchEnv 	( MatchEnv )
import Name		( Module(..), OccName, Name, ExportFlag, NamedThing(..) )
import Outputable	( Outputable(..) )
import PprStyle		( PprStyle )
import PragmaInfo	( PragmaInfo )
import Pretty		( PrettyRep )
import PrimOp		( PrimOp )
import PrimRep		( PrimRep )
import SMRep		( SMRep )
import SrcLoc		( SrcLoc )
import TcType		( TcMaybe )
import TyCon		( TyCon, Arity(..) )
import TyVar		( GenTyVar, TyVar(..) )
import Type		( GenType, Type(..) )
import UniqFM		( UniqFM, Uniquable(..) )
import UniqSupply	( UniqSupply )
import Unique		( Unique )
import Usage		( GenUsage, Usage(..) )
import Util		( Ord3(..) )

-- All the classes in GHC go; life is just too short
-- to try to contain their visibility.

class NamedThing a where
	getOccName :: a -> OccName
	getName    :: a -> Name

class Ord3 a where
	cmp :: a -> a -> Int#
class Outputable a where
	ppr :: PprStyle -> a -> Int -> Bool -> PrettyRep
class Uniquable a where
	uniqueOf :: a -> Unique

-- For datatypes, we ubiquitize those types that (a) are
-- used everywhere and (b) the compiler doesn't lose much
-- optimisation-wise by not seeing their pragma-gunk.

data ArityInfo
data Bag a
data BinderInfo
data CgIdInfo
data CLabel
data ClassOpPragmas a
data ClassPragmas a
data ClosureInfo
data Coercion
data CostCentre
data CSeq
data DataPragmas a
data DeforestInfo
data Demand
data ExportFlag
data FieldLabel
data FiniteMap a b
data GenClass a b
data GenClassOp a
data GenCoreArg a b c
data GenCoreBinder a b c
data GenCoreBinding a b c d
data GenCoreCaseAlts a b c d
data GenCoreCaseDefault a b c d
data GenCoreExpr a b c d
data GenId a	-- NB: fails the optimisation criterion
data GenPragmas a
data GenTyVar a	-- NB: fails the optimisation criterion
data GenType  a b
data GenUsage a
data HeapOffset
data IdInfo
data InstancePragmas a
data Kind
data LambdaFormInfo
data Literal
data MaybeErr a b
data MatchEnv a b
data Name
data OccName
data Reg
data OutPat a b c
data PprStyle
data PragmaInfo
data PrettyRep
data PrimOp
data PrimRep	-- NB: an enumeration
data SimplifierSwitch
data SMRep
data SrcLoc
data StrictnessInfo bdee
data StrictnessMark
data SwitchResult
data TcMaybe s
data TyCon
data UniqFM a
data UpdateInfo
data UniqSupply
data Unfolding
data UnfoldingGuidance
data Unique	-- NB: fails the optimisation criterion

-- don't get clever and unexpand some of these synonyms
-- (GHC 0.26 will barf)
type Module = FastString
type Arity = Int
type Class = GenClass (GenTyVar (GenUsage Unique)) Unique
type ClassOp = GenClassOp (GenType (GenTyVar (GenUsage Unique)) Unique)
type Id	   = GenId (GenType (GenTyVar (GenUsage Unique)) Unique)
type Type  = GenType (GenTyVar (GenUsage Unique)) Unique
type TyVar = GenTyVar (GenUsage Unique)
type Usage = GenUsage Unique

-- These are here only for SPECIALIZing in FiniteMap (ToDo:move?)
instance Ord Reg
instance Ord CLabel
instance Ord TyCon
instance Eq Reg
instance Eq CLabel
instance Eq TyCon
-- specializing in UniqFM, UniqSet
instance Uniquable Unique
instance Uniquable Name
-- specializing in Name
\end{code}