%
% (c) The GRASP/AQUA Project, Glasgow University, 1998
%
-\section[Type]{Type}
+\section[Type]{Type - public interface}
\begin{code}
module Type (
- Type(..), TyNote(..), UsageAnn(..), -- Representation visible to friends
+ -- re-exports from TypeRep:
+ Type,
Kind, TyVarSubst,
superKind, superBoxity, -- :: SuperKind
boxedTypeKind, unboxedTypeKind, openTypeKind, -- Kind :: superKind
- mkArrowKind, mkArrowKinds, hasMoreBoxityInfo,
+ mkArrowKind, mkArrowKinds, -- mentioned below: hasMoreBoxityInfo,
funTyCon,
+ -- exports from this module:
+ hasMoreBoxityInfo,
+
mkTyVarTy, mkTyVarTys, getTyVar, getTyVar_maybe, isTyVarTy,
mkAppTy, mkAppTys, splitAppTy, splitAppTys, splitAppTy_maybe,
mkFunTy, mkFunTys, splitFunTy_maybe, splitFunTys, splitFunTysN,
- funResultTy, funArgTy,
- zipFunTys,
+ funResultTy, funArgTy, zipFunTys,
mkTyConApp, mkTyConTy, splitTyConApp_maybe,
splitAlgTyConApp_maybe, splitAlgTyConApp,
mkDictTy, splitDictTy_maybe, isDictTy,
- mkSynTy, isSynTy, deNoteType, repType, newTypeRep,
+ mkSynTy, isSynTy, deNoteType, repType, splitNewType_maybe,
- mkUsgTy, isUsgTy{- dont use -}, isNotUsgTy, splitUsgTy, unUsgTy, tyUsg,
+ UsageAnn(..), mkUsgTy, isUsgTy{- dont use -}, isNotUsgTy, splitUsgTy, unUsgTy, tyUsg,
+ mkUsForAllTy, mkUsForAllTys, splitUsForAllTys, substUsTy,
mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys,
isForAllTy, applyTy, applyTys, mkPiType,
tidyType, tidyTypes,
tidyOpenType, tidyOpenTypes,
tidyTyVar, tidyTyVars,
- tidyTopType
+ tidyTopType,
+
+ -- Seq
+ seqType, seqTypes
+
) where
#include "HsVersions.h"
+-- We import the representation and primitive functions from TypeRep.
+-- Many things are reexported, but not the representation!
+
+import TypeRep
+
+-- Other imports:
+
import {-# SOURCE #-} DataCon( DataCon, dataConType )
import {-# SOURCE #-} PprType( pprType ) -- Only called in debug messages
import {-# SOURCE #-} Subst ( mkTyVarSubst, substTy )
-- friends:
-import Var ( Id, TyVar, IdOrTyVar, UVar,
- tyVarKind, tyVarName, isId, idType, setTyVarName, setVarOcc
+import Var ( TyVar, IdOrTyVar, UVar,
+ tyVarKind, tyVarName, setTyVarName, isId, idType,
)
import VarEnv
import VarSet
-import Name ( NamedThing(..), Provenance(..), ExportFlag(..),
- mkWiredInTyConName, mkGlobalName, mkLocalName, mkKindOccFS, tcName,
- tidyOccName, TidyOccEnv
+import Name ( NamedThing(..), mkLocalName, tidyOccName,
)
import NameSet
import Class ( classTyCon, Class )
-import TyCon ( TyCon, KindCon,
- mkFunTyCon, mkKindCon, mkSuperKindCon,
- matchesTyCon, isUnboxedTupleTyCon, isUnLiftedTyCon,
+import TyCon ( TyCon,
+ isUnboxedTupleTyCon, isUnLiftedTyCon,
isFunTyCon, isDataTyCon, isNewTyCon,
isAlgTyCon, isSynTyCon, tyConArity,
- tyConKind, tyConDataCons, getSynTyConDefn,
+ tyConKind, tyConDataCons, getSynTyConDefn,
tyConPrimRep, tyConClass_maybe
)
-- others
-import BasicTypes ( Unused )
-import SrcLoc ( mkBuiltinSrcLoc, noSrcLoc )
-import PrelMods ( pREL_GHC )
+import SrcLoc ( noSrcLoc )
import Maybes ( maybeToBool )
import PrimRep ( PrimRep(..), isFollowableRep )
-import Unique -- quite a few *Keys
-import Util ( thenCmp, mapAccumL, seqList, ($!) )
+import Unique ( Uniquable(..) )
+import Util ( mapAccumL, seqList )
import Outputable
-
-\end{code}
-
-%************************************************************************
-%* *
-\subsection{Type Classifications}
-%* *
-%************************************************************************
-
-A type is
-
- *unboxed* iff its representation is other than a pointer
- Unboxed types cannot instantiate a type variable.
- Unboxed types are always unlifted.
-
- *lifted* A type is lifted iff it has bottom as an element.
- Closures always have lifted types: i.e. any
- let-bound identifier in Core must have a lifted
- type. Operationally, a lifted object is one that
- can be entered.
- (NOTE: previously "pointed").
-
- *algebraic* A type with one or more constructors, whether declared
- with "data" or "newtype".
- An algebraic type is one that can be deconstructed
- with a case expression.
- *NOT* the same as lifted types, because we also
- include unboxed tuples in this classification.
-
- *data* A type declared with "data". Also boxed tuples.
-
- *primitive* iff it is a built-in type that can't be expressed
- in Haskell.
-
-Currently, all primitive types are unlifted, but that's not necessarily
-the case. (E.g. Int could be primitive.)
-
-Some primitive types are unboxed, such as Int#, whereas some are boxed
-but unlifted (such as ByteArray#). The only primitive types that we
-classify as algebraic are the unboxed tuples.
-
-examples of type classifications:
-
-Type primitive boxed lifted algebraic
------------------------------------------------------------------------------
-Int#, Yes No No No
-ByteArray# Yes Yes No No
-(# a, b #) Yes No No Yes
-( a, b ) No Yes Yes Yes
-[a] No Yes Yes Yes
-
-%************************************************************************
-%* *
-\subsection{The data type}
-%* *
-%************************************************************************
-
-
-\begin{code}
-type SuperKind = Type
-type Kind = Type
-
-type TyVarSubst = TyVarEnv Type
-
-data Type
- = TyVarTy TyVar
-
- | AppTy
- Type -- Function is *not* a TyConApp
- Type
-
- | TyConApp -- Application of a TyCon
- TyCon -- *Invariant* saturated appliations of FunTyCon and
- -- synonyms have their own constructors, below.
- [Type] -- Might not be saturated.
-
- | FunTy -- Special case of TyConApp: TyConApp FunTyCon [t1,t2]
- Type
- Type
-
- | NoteTy -- Saturated application of a type synonym
- TyNote
- Type -- The expanded version
-
- | ForAllTy
- TyVar
- Type -- TypeKind
-
-data TyNote
- = SynNote Type -- The unexpanded version of the type synonym; always a TyConApp
- | FTVNote TyVarSet -- The free type variables of the noted expression
- | UsgNote UsageAnn -- The usage annotation at this node
-
-data UsageAnn
- = UsOnce -- Used at most once
- | UsMany -- Used possibly many times (no info; this annotation can be omitted)
- | UsVar UVar -- Annotation is variable (should only happen inside analysis)
+import UniqSet ( sizeUniqSet ) -- Should come via VarSet
\end{code}
%************************************************************************
%* *
-\subsection{Kinds}
+\subsection{Stuff to do with kinds.}
%* *
%************************************************************************
-Kinds
-~~~~~
-k::K = Type bx
- | k -> k
- | kv
-
-kv :: KX is a kind variable
-
-Type :: BX -> KX
-
-bx::BX = Boxed
- | Unboxed
- | AnyBox -- Used *only* for special built-in things
- -- like error :: forall (a::*?). String -> a
- -- Here, the 'a' can be instantiated to a boxed or
- -- unboxed type.
- | bv
-
-bxv :: BX is a boxity variable
-
-sk = KX -- A kind
- | BX -- A boxity
- | sk -> sk -- In ptic (BX -> KX)
-
-\begin{code}
-mk_kind_name key str = mkGlobalName key pREL_GHC (mkKindOccFS tcName str)
- (LocalDef mkBuiltinSrcLoc NotExported)
- -- mk_kind_name is a bit of a hack
- -- The LocalDef means that we print the name without
- -- a qualifier, which is what we want for these kinds.
- -- It's used for both Kinds and Boxities
-\end{code}
-
-Define KX, BX.
-
-\begin{code}
-superKind :: SuperKind -- KX, the type of all kinds
-superKindName = mk_kind_name kindConKey SLIT("KX")
-superKind = TyConApp (mkSuperKindCon superKindName) []
-
-superBoxity :: SuperKind -- BX, the type of all boxities
-superBoxityName = mk_kind_name boxityConKey SLIT("BX")
-superBoxity = TyConApp (mkSuperKindCon superBoxityName) []
-\end{code}
-
-Define Boxed, Unboxed, AnyBox
-
-\begin{code}
-boxedKind, unboxedKind, anyBoxKind :: Kind -- Of superkind superBoxity
-
-boxedConName = mk_kind_name boxedConKey SLIT("*")
-boxedKind = TyConApp (mkKindCon boxedConName superBoxity) []
-
-unboxedConName = mk_kind_name unboxedConKey SLIT("#")
-unboxedKind = TyConApp (mkKindCon unboxedConName superBoxity) []
-
-anyBoxConName = mk_kind_name anyBoxConKey SLIT("?")
-anyBoxCon = mkKindCon anyBoxConName superBoxity -- A kind of wild card
-anyBoxKind = TyConApp anyBoxCon []
-\end{code}
-
-Define Type
-
-\begin{code}
-typeCon :: KindCon
-typeConName = mk_kind_name typeConKey SLIT("Type")
-typeCon = mkKindCon typeConName (superBoxity `FunTy` superKind)
-\end{code}
-
-Define (Type Boxed), (Type Unboxed), (Type AnyBox)
-
-\begin{code}
-boxedTypeKind, unboxedTypeKind, openTypeKind :: Kind
-boxedTypeKind = TyConApp typeCon [boxedKind]
-unboxedTypeKind = TyConApp typeCon [unboxedKind]
-openTypeKind = TyConApp typeCon [anyBoxKind]
-
-mkArrowKind :: Kind -> Kind -> Kind
-mkArrowKind k1 k2 = k1 `FunTy` k2
-
-mkArrowKinds :: [Kind] -> Kind -> Kind
-mkArrowKinds arg_kinds result_kind = foldr mkArrowKind result_kind arg_kinds
-\end{code}
-
\begin{code}
hasMoreBoxityInfo :: Kind -> Kind -> Bool
hasMoreBoxityInfo k1 k2
%************************************************************************
%* *
-\subsection{Wired-in type constructors
-%* *
-%************************************************************************
-
-We define a few wired-in type constructors here to avoid module knots
-
-\begin{code}
-funTyConName = mkWiredInTyConName funTyConKey pREL_GHC SLIT("(->)") funTyCon
-funTyCon = mkFunTyCon funTyConName (mkArrowKinds [boxedTypeKind, boxedTypeKind] boxedTypeKind)
-\end{code}
-
-
-
-%************************************************************************
-%* *
\subsection{Constructor-specific functions}
%* *
%************************************************************************
mkSynTy syn_tycon tys
= ASSERT( isSynTyCon syn_tycon )
ASSERT( isNotUsgTy body )
+ ASSERT( length tyvars == length tys )
NoteTy (SynNote (TyConApp syn_tycon tys))
(substTy (mkTyVarSubst tyvars tys) body)
where
repType :: Type -> Type
repType (NoteTy _ ty) = repType ty
repType (ForAllTy _ ty) = repType ty
-repType (TyConApp tc tys) | isNewTyCon tc = repType (newTypeRep tc tys)
+repType (TyConApp tc tys) | isNewTyCon tc = repType (new_type_rep tc tys)
repType other_ty = other_ty
-newTypeRep :: TyCon -> [Type] -> Type
+splitNewType_maybe :: Type -> Maybe Type
+-- Find the representation of a newtype, if it is one
+-- Looks through multiple levels of newtype
+splitNewType_maybe (NoteTy _ ty) = splitNewType_maybe ty
+splitNewType_maybe (TyConApp tc tys) | isNewTyCon tc = case splitNewType_maybe rep_ty of
+ Just rep_ty' -> Just rep_ty'
+ Nothing -> Just rep_ty
+ where
+ rep_ty = new_type_rep tc tys
+
+splitNewType_maybe other = Nothing
+
+new_type_rep :: TyCon -> [Type] -> Type
-- The representation type for (T t1 .. tn), where T is a newtype
-- Looks through one layer only
-newTypeRep tc tys
+new_type_rep tc tys
= ASSERT( isNewTyCon tc )
case splitFunTy_maybe (applyTys (dataConType (head (tyConDataCons tc))) tys) of
Just (rep_ty, _) -> rep_ty
This should be carefully preserved.
In some parts of the compiler, comments use the _Once Upon a
-Polymorphic Type_ (POPL'99) usage of "sigma = usage-annotated type;
-tau = un-usage-annotated type"; unfortunately this conflicts with the
-rho/tau/theta/sigma usage in the rest of the compiler.
-(KSW 1999-04)
+Polymorphic Type_ (POPL'99) usage of "rho = generalised
+usage-annotated type; sigma = usage-annotated type; tau =
+usage-annotated type except on top"; unfortunately this conflicts with
+the rho/tau/theta/sigma usage in the rest of the compiler. (KSW
+1999-07)
\begin{code}
mkUsgTy :: UsageAnn -> Type -> Type
#ifndef USMANY
isUsgTy _ = True
#else
-isUsgTy (NoteTy (UsgNote _) _) = True
-isUsgTy other = False
+isUsgTy (NoteTy (UsgForAll _) ty) = isUsgTy ty
+isUsgTy (NoteTy (UsgNote _) _ ) = True
+isUsgTy other = False
#endif
-- The isNotUsgTy function may return a false True if UsManys are omitted;
-- in other words, A SSERT( isNotUsgTy ty ) may be useful but
-- A SSERT( not (isNotUsg ty) ) is asking for trouble. KSW 1999-04.
isNotUsgTy :: Type -> Bool
-isNotUsgTy (NoteTy (UsgNote _) _) = False
-isNotUsgTy other = True
+isNotUsgTy (NoteTy (UsgForAll _) _) = False
+isNotUsgTy (NoteTy (UsgNote _) _) = False
+isNotUsgTy other = True
-- splitUsgTy_maybe is not exported, since it is meaningless if
-- UsManys are omitted. It is used in several places in this module,
splitUsgTy_maybe :: Type -> Maybe (UsageAnn,Type)
splitUsgTy_maybe (NoteTy (UsgNote usg) ty2) = ASSERT( isNotUsgTy ty2 )
Just (usg,ty2)
-splitUsgTy_maybe ty = Nothing
+splitUsgTy_maybe ty@(NoteTy (UsgForAll _) _) = pprPanic "splitUsgTy_maybe:" $ pprType ty
+splitUsgTy_maybe ty = Nothing
splitUsgTy :: Type -> (UsageAnn,Type)
splitUsgTy ty = case splitUsgTy_maybe ty of
Just (_,ty1) -> ASSERT2( isNotUsgTy ty1, pprType ty )
ty1
Nothing -> ty
-\end{code}
+mkUsForAllTy :: UVar -> Type -> Type
+mkUsForAllTy uv ty = NoteTy (UsgForAll uv) ty
+
+mkUsForAllTys :: [UVar] -> Type -> Type
+mkUsForAllTys uvs ty = foldr (NoteTy . UsgForAll) ty uvs
+
+splitUsForAllTys :: Type -> ([UVar],Type)
+splitUsForAllTys ty = split ty []
+ where split (NoteTy (UsgForAll u) ty) uvs = split ty (u:uvs)
+ split other_ty uvs = (reverse uvs, other_ty)
+
+substUsTy :: VarEnv UsageAnn -> Type -> Type
+-- assumes range is fresh uvars, so no conflicts
+substUsTy ve (NoteTy note@(UsgNote (UsVar u))
+ ty ) = NoteTy (case lookupVarEnv ve u of
+ Just ua -> UsgNote ua
+ Nothing -> note)
+ (substUsTy ve ty)
+substUsTy ve (NoteTy note@(UsgNote _) ty ) = NoteTy note (substUsTy ve ty)
+substUsTy ve (NoteTy note@(UsgForAll _) ty ) = NoteTy note (substUsTy ve ty)
+substUsTy ve (NoteTy (SynNote ty1) ty2) = NoteTy (SynNote (substUsTy ve ty1))
+ (substUsTy ve ty2)
+substUsTy ve (NoteTy note@(FTVNote _) ty ) = NoteTy note (substUsTy ve ty)
+substUsTy ve ty@(TyVarTy _ ) = ty
+substUsTy ve (AppTy ty1 ty2) = AppTy (substUsTy ve ty1)
+ (substUsTy ve ty2)
+substUsTy ve (FunTy ty1 ty2) = FunTy (substUsTy ve ty1)
+ (substUsTy ve ty2)
+substUsTy ve (TyConApp tyc tys) = TyConApp tyc (map (substUsTy ve) tys)
+substUsTy ve (ForAllTy yv ty ) = ForAllTy yv (substUsTy ve ty)
+\end{code}
---------------------------------------------------------------------
\begin{code}
applyTy :: Type -> Type -> Type
-applyTy (NoteTy note@(UsgNote _) fun) arg = NoteTy note (applyTy fun arg)
-applyTy (NoteTy _ fun) arg = applyTy fun arg
-applyTy (ForAllTy tv ty) arg = ASSERT( isNotUsgTy arg )
- substTy (mkTyVarSubst [tv] [arg]) ty
-applyTy other arg = panic "applyTy"
+applyTy (NoteTy note@(UsgNote _) fun) arg = NoteTy note (applyTy fun arg)
+applyTy (NoteTy note@(UsgForAll _) fun) arg = NoteTy note (applyTy fun arg)
+applyTy (NoteTy _ fun) arg = applyTy fun arg
+applyTy (ForAllTy tv ty) arg = ASSERT( isNotUsgTy arg )
+ substTy (mkTyVarSubst [tv] [arg]) ty
+applyTy other arg = panic "applyTy"
applyTys :: Type -> [Type] -> Type
applyTys fun_ty arg_tys
(tvs, ty) = split fun_ty arg_tys
split fun_ty [] = ([], fun_ty)
+ split (NoteTy note@(UsgNote _) fun_ty)
+ args = case split fun_ty args of
+ (tvs, ty) -> (tvs, NoteTy note ty)
+ split (NoteTy note@(UsgForAll _) fun_ty)
+ args = case split fun_ty args of
+ (tvs, ty) -> (tvs, NoteTy note ty)
split (NoteTy _ fun_ty) args = split fun_ty args
split (ForAllTy tv fun_ty) (arg:args) = ASSERT2( isNotUsgTy arg, vcat (map pprType arg_tys) $$
text "in application of" <+> pprType fun_ty)
case split fun_ty args of
(tvs, ty) -> (tv:tvs, ty)
split other_ty args = panic "applyTys"
-
-{- OLD version with bogus usage stuff
-
- ************* CHECK WITH KEITH **************
-
- go env ty [] = substTy (mkVarEnv env) ty
- go env (NoteTy note@(UsgNote _) fun)
- args = NoteTy note (go env fun args)
- go env (NoteTy _ fun) args = go env fun args
- go env (ForAllTy tv ty) (arg:args) = go ((tv,arg):env) ty args
- go env other args = panic "applyTys"
--}
\end{code}
Note that we allow applications to be of usage-annotated- types, as an
extension: we handle them by lifting the annotation outside. The
argument, however, must still be unannotated.
+
%************************************************************************
%* *
\subsection{Stuff to do with the source-language types}
tyVarsOfType (NoteTy (FTVNote tvs) ty2) = tvs
tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty1
tyVarsOfType (NoteTy (UsgNote _) ty) = tyVarsOfType ty
+tyVarsOfType (NoteTy (UsgForAll _) ty) = tyVarsOfType ty
tyVarsOfType (FunTy arg res) = tyVarsOfType arg `unionVarSet` tyVarsOfType res
tyVarsOfType (AppTy fun arg) = tyVarsOfType fun `unionVarSet` tyVarsOfType arg
tyVarsOfType (ForAllTy tyvar ty) = tyVarsOfType ty `minusVarSet` unitVarSet tyvar
-- Add a Note with the free tyvars to the top of the type
-- (but under a usage if there is one)
addFreeTyVars :: Type -> Type
-addFreeTyVars (NoteTy note@(UsgNote _) ty) = NoteTy note (addFreeTyVars ty)
-addFreeTyVars ty@(NoteTy (FTVNote _) _) = ty
-addFreeTyVars ty = NoteTy (FTVNote (tyVarsOfType ty)) ty
+addFreeTyVars (NoteTy note@(UsgNote _) ty) = NoteTy note (addFreeTyVars ty)
+addFreeTyVars (NoteTy note@(UsgForAll _) ty) = NoteTy note (addFreeTyVars ty)
+addFreeTyVars ty@(NoteTy (FTVNote _) _) = ty
+addFreeTyVars ty = NoteTy (FTVNote (tyVarsOfType ty)) ty
-- Find the free names of a type, including the type constructors and classes it mentions
namesOfType :: Type -> NameSet
Just tv' -> TyVarTy tv'
go (TyConApp tycon tys) = let args = map go tys
in args `seqList` TyConApp tycon args
- go (NoteTy note ty) = (NoteTy $! (go_note note)) $! (go ty)
- go (AppTy fun arg) = (AppTy $! (go fun)) $! (go arg)
- go (FunTy fun arg) = (FunTy $! (go fun)) $! (go arg)
- go (ForAllTy tv ty) = ForAllTy tv' $! (tidyType env' ty)
- where
- (env', tv') = tidyTyVar env tv
+ go (NoteTy note ty) = (NoteTy SAPPLY (go_note note)) SAPPLY (go ty)
+ go (AppTy fun arg) = (AppTy SAPPLY (go fun)) SAPPLY (go arg)
+ go (FunTy fun arg) = (FunTy SAPPLY (go fun)) SAPPLY (go arg)
+ go (ForAllTy tv ty) = ForAllTy tvp SAPPLY (tidyType envp ty)
+ where
+ (envp, tvp) = tidyTyVar env tv
- go_note (SynNote ty) = SynNote $! (go ty)
+ go_note (SynNote ty) = SynNote SAPPLY (go ty)
go_note note@(FTVNote ftvs) = note -- No need to tidy the free tyvars
go_note note@(UsgNote _) = note -- Usage annotation is already tidy
+ go_note note@(UsgForAll _) = note -- Uvar binder is already tidy
tidyTypes env tys = map (tidyType env) tys
\end{code}
-@tidyOpenType@ grabs the free type varibles, tidies them
+@tidyOpenType@ grabs the free type variables, tidies them
and then uses @tidyType@ to work over the type itself
\begin{code}
isUnboxedType ty = not (isFollowableRep (typePrimRep ty))
isUnLiftedType :: Type -> Bool
-isUnLiftedType ty = case splitTyConApp_maybe ty of
- Just (tc, ty_args) -> isUnLiftedTyCon tc
- other -> False
+ -- isUnLiftedType returns True for forall'd unlifted types:
+ -- x :: forall a. Int#
+ -- I found bindings like these were getting floated to the top level.
+ -- They are pretty bogus types, mind you. It would be better never to
+ -- construct them
+
+isUnLiftedType (ForAllTy tv ty) = isUnLiftedType ty
+isUnLiftedType (NoteTy _ ty) = isUnLiftedType ty
+isUnLiftedType (TyConApp tc _) = isUnLiftedTyCon tc
+isUnLiftedType other = False
isUnboxedTupleType :: Type -> Bool
isUnboxedTupleType ty = case splitTyConApp_maybe ty of
other -> PtrRep
\end{code}
+
%************************************************************************
%* *
-\subsection{Equality on types}
+\subsection{Sequencing on types
%* *
%************************************************************************
-For the moment at least, type comparisons don't work if
-there are embedded for-alls.
-
\begin{code}
-instance Eq Type where
- ty1 == ty2 = case ty1 `cmpTy` ty2 of { EQ -> True; other -> False }
-
-instance Ord Type where
- compare ty1 ty2 = cmpTy ty1 ty2
-
-cmpTy :: Type -> Type -> Ordering
-cmpTy ty1 ty2
- = cmp emptyVarEnv ty1 ty2
- where
- -- The "env" maps type variables in ty1 to type variables in ty2
- -- So when comparing for-alls.. (forall tv1 . t1) (forall tv2 . t2)
- -- we in effect substitute tv2 for tv1 in t1 before continuing
- lookup env tv1 = case lookupVarEnv env tv1 of
- Just tv2 -> tv2
- Nothing -> tv1
-
- -- Get rid of NoteTy
- cmp env (NoteTy _ ty1) ty2 = cmp env ty1 ty2
- cmp env ty1 (NoteTy _ ty2) = cmp env ty1 ty2
-
- -- Deal with equal constructors
- cmp env (TyVarTy tv1) (TyVarTy tv2) = lookup env tv1 `compare` tv2
- cmp env (AppTy f1 a1) (AppTy f2 a2) = cmp env f1 f2 `thenCmp` cmp env a1 a2
- cmp env (FunTy f1 a1) (FunTy f2 a2) = cmp env f1 f2 `thenCmp` cmp env a1 a2
- cmp env (TyConApp tc1 tys1) (TyConApp tc2 tys2) = (tc1 `compare` tc2) `thenCmp` (cmps env tys1 tys2)
- cmp env (ForAllTy tv1 t1) (ForAllTy tv2 t2) = cmp (extendVarEnv env tv1 tv2) t1 t2
-
- -- Deal with the rest: TyVarTy < AppTy < FunTy < TyConApp < ForAllTy
- cmp env (AppTy _ _) (TyVarTy _) = GT
-
- cmp env (FunTy _ _) (TyVarTy _) = GT
- cmp env (FunTy _ _) (AppTy _ _) = GT
-
- cmp env (TyConApp _ _) (TyVarTy _) = GT
- cmp env (TyConApp _ _) (AppTy _ _) = GT
- cmp env (TyConApp _ _) (FunTy _ _) = GT
-
- cmp env (ForAllTy _ _) other = GT
-
- cmp env _ _ = LT
-
- cmps env [] [] = EQ
- cmps env (t:ts) [] = GT
- cmps env [] (t:ts) = LT
- cmps env (t1:t1s) (t2:t2s) = cmp env t1 t2 `thenCmp` cmps env t1s t2s
+seqType :: Type -> ()
+seqType (TyVarTy tv) = tv `seq` ()
+seqType (AppTy t1 t2) = seqType t1 `seq` seqType t2
+seqType (FunTy t1 t2) = seqType t1 `seq` seqType t2
+seqType (NoteTy note t2) = seqNote note `seq` seqType t2
+seqType (TyConApp tc tys) = tc `seq` seqTypes tys
+seqType (ForAllTy tv ty) = tv `seq` seqType ty
+
+seqTypes :: [Type] -> ()
+seqTypes [] = ()
+seqTypes (ty:tys) = seqType ty `seq` seqTypes tys
+
+seqNote :: TyNote -> ()
+seqNote (SynNote ty) = seqType ty
+seqNote (FTVNote set) = sizeUniqSet set `seq` ()
+seqNote (UsgNote usg) = usg `seq` ()
\end{code}
-