2 % (c) The GRASP/AQUA Project, Glasgow University, 1998
4 \section[Type]{Type - public interface}
8 -- re-exports from TypeRep:
12 superKind, superBoxity, -- :: SuperKind
14 boxedKind, -- :: Kind :: BX
15 anyBoxKind, -- :: Kind :: BX
16 typeCon, -- :: KindCon :: BX -> KX
17 anyBoxCon, -- :: KindCon :: BX
19 boxedTypeKind, unboxedTypeKind, openTypeKind, -- Kind :: superKind
21 mkArrowKind, mkArrowKinds, -- mentioned below: hasMoreBoxityInfo,
25 -- exports from this module:
28 mkTyVarTy, mkTyVarTys, getTyVar, getTyVar_maybe, isTyVarTy,
30 mkAppTy, mkAppTys, splitAppTy, splitAppTys, splitAppTy_maybe,
32 mkFunTy, mkFunTys, splitFunTy, splitFunTy_maybe, splitFunTys, splitFunTysN,
33 funResultTy, funArgTy, zipFunTys,
35 mkTyConApp, mkTyConTy, splitTyConApp_maybe,
36 splitAlgTyConApp_maybe, splitAlgTyConApp,
37 mkDictTy, mkDictTys, mkPredTy, splitPredTy_maybe, splitDictTy_maybe, isDictTy,
39 mkSynTy, isSynTy, deNoteType,
41 repType, splitRepFunTys, splitNewType_maybe, typePrimRep,
43 UsageAnn(..), mkUsgTy, isUsgTy{- dont use -}, isNotUsgTy, splitUsgTy, unUsgTy, tyUsg,
44 mkUsForAllTy, mkUsForAllTys, splitUsForAllTys, substUsTy,
46 mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys,
47 isForAllTy, applyTy, applyTys, mkPiType, hoistForAllTys,
49 TauType, RhoType, SigmaType, PredType(..), ThetaType,
50 ClassPred, ClassContext, mkClassPred,
51 getClassTys_maybe, ipName_maybe, classesToPreds, classesOfPreds,
52 isTauTy, mkRhoTy, splitRhoTy,
53 mkSigmaTy, splitSigmaTy,
56 isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType, isDataType, isNewType,
59 tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta,
60 namesOfType, typeKind, addFreeTyVars,
62 -- Tidying up for printing
64 tidyOpenType, tidyOpenTypes,
65 tidyTyVar, tidyTyVars,
73 #include "HsVersions.h"
75 -- We import the representation and primitive functions from TypeRep.
76 -- Many things are reexported, but not the representation!
82 import {-# SOURCE #-} DataCon( DataCon, dataConRepType )
83 import {-# SOURCE #-} PprType( pprType, pprPred ) -- Only called in debug messages
84 import {-# SOURCE #-} Subst ( mkTyVarSubst, substTy )
87 import Var ( TyVar, Var, UVar,
88 tyVarKind, tyVarName, setTyVarName, isId, idType,
93 import Name ( Name, NamedThing(..), mkLocalName, tidyOccName
96 import Class ( classTyCon, Class )
98 isUnboxedTupleTyCon, isUnLiftedTyCon,
99 isFunTyCon, isDataTyCon, isNewTyCon, newTyConRep,
100 isAlgTyCon, isSynTyCon, tyConArity,
101 tyConKind, tyConDataCons, getSynTyConDefn,
102 tyConPrimRep, tyConClass_maybe
106 import SrcLoc ( noSrcLoc )
107 import Maybes ( maybeToBool )
108 import PrimRep ( PrimRep(..), isFollowableRep )
109 import Unique ( Uniquable(..) )
110 import Util ( mapAccumL, seqList )
112 import UniqSet ( sizeUniqSet ) -- Should come via VarSet
116 %************************************************************************
118 \subsection{Stuff to do with kinds.}
120 %************************************************************************
123 hasMoreBoxityInfo :: Kind -> Kind -> Bool
124 hasMoreBoxityInfo k1 k2
125 | k2 == openTypeKind = ASSERT( is_type_kind k1) True
126 | otherwise = k1 == k2
128 -- Returns true for things of form (Type x)
129 is_type_kind k = case splitTyConApp_maybe k of
130 Just (tc,[_]) -> tc == typeCon
135 %************************************************************************
137 \subsection{Constructor-specific functions}
139 %************************************************************************
142 ---------------------------------------------------------------------
146 mkTyVarTy :: TyVar -> Type
149 mkTyVarTys :: [TyVar] -> [Type]
150 mkTyVarTys = map mkTyVarTy -- a common use of mkTyVarTy
152 getTyVar :: String -> Type -> TyVar
153 getTyVar msg (TyVarTy tv) = tv
154 getTyVar msg (NoteTy _ t) = getTyVar msg t
155 getTyVar msg other = panic ("getTyVar: " ++ msg)
157 getTyVar_maybe :: Type -> Maybe TyVar
158 getTyVar_maybe (TyVarTy tv) = Just tv
159 getTyVar_maybe (NoteTy _ t) = getTyVar_maybe t
160 getTyVar_maybe other = Nothing
162 isTyVarTy :: Type -> Bool
163 isTyVarTy (TyVarTy tv) = True
164 isTyVarTy (NoteTy _ ty) = isTyVarTy ty
165 isTyVarTy other = False
169 ---------------------------------------------------------------------
172 We need to be pretty careful with AppTy to make sure we obey the
173 invariant that a TyConApp is always visibly so. mkAppTy maintains the
177 mkAppTy orig_ty1 orig_ty2 = ASSERT2( isNotUsgTy orig_ty1 && isNotUsgTy orig_ty2, pprType orig_ty1 <+> text "to" <+> pprType orig_ty2 )
180 mk_app (NoteTy _ ty1) = mk_app ty1
181 mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ [orig_ty2])
182 mk_app ty1 = AppTy orig_ty1 orig_ty2
184 mkAppTys :: Type -> [Type] -> Type
185 mkAppTys orig_ty1 [] = orig_ty1
186 -- This check for an empty list of type arguments
187 -- avoids the needless of a type synonym constructor.
188 -- For example: mkAppTys Rational []
189 -- returns to (Ratio Integer), which has needlessly lost
190 -- the Rational part.
191 mkAppTys orig_ty1 orig_tys2 = ASSERT2( isNotUsgTy orig_ty1, pprType orig_ty1 )
194 mk_app (NoteTy _ ty1) = mk_app ty1
195 mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ orig_tys2)
196 mk_app ty1 = ASSERT2( all isNotUsgTy orig_tys2, pprType orig_ty1 <+> text "to" <+> hsep (map pprType orig_tys2) )
197 foldl AppTy orig_ty1 orig_tys2
199 splitAppTy_maybe :: Type -> Maybe (Type, Type)
200 splitAppTy_maybe (FunTy ty1 ty2) = Just (TyConApp funTyCon [ty1], ty2)
201 splitAppTy_maybe (AppTy ty1 ty2) = Just (ty1, ty2)
202 splitAppTy_maybe (NoteTy _ ty) = splitAppTy_maybe ty
203 splitAppTy_maybe (TyConApp tc []) = Nothing
204 splitAppTy_maybe (TyConApp tc tys) = split tys []
206 split [ty2] acc = Just (TyConApp tc (reverse acc), ty2)
207 split (ty:tys) acc = split tys (ty:acc)
209 splitAppTy_maybe other = Nothing
211 splitAppTy :: Type -> (Type, Type)
212 splitAppTy ty = case splitAppTy_maybe ty of
214 Nothing -> panic "splitAppTy"
216 splitAppTys :: Type -> (Type, [Type])
217 splitAppTys ty = split ty ty []
219 split orig_ty (AppTy ty arg) args = split ty ty (arg:args)
220 split orig_ty (NoteTy _ ty) args = split orig_ty ty args
221 split orig_ty (FunTy ty1 ty2) args = ASSERT( null args )
222 (TyConApp funTyCon [], [ty1,ty2])
223 split orig_ty (TyConApp tc tc_args) args = (TyConApp tc [], tc_args ++ args)
224 split orig_ty ty args = (orig_ty, args)
228 ---------------------------------------------------------------------
233 mkFunTy :: Type -> Type -> Type
234 mkFunTy arg res = FunTy arg res
236 mkFunTys :: [Type] -> Type -> Type
237 mkFunTys tys ty = foldr FunTy ty tys
239 splitFunTy :: Type -> (Type, Type)
240 splitFunTy (FunTy arg res) = (arg, res)
241 splitFunTy (NoteTy _ ty) = splitFunTy ty
243 splitFunTy_maybe :: Type -> Maybe (Type, Type)
244 splitFunTy_maybe (FunTy arg res) = Just (arg, res)
245 splitFunTy_maybe (NoteTy _ ty) = splitFunTy_maybe ty
246 splitFunTy_maybe other = Nothing
248 splitFunTys :: Type -> ([Type], Type)
249 splitFunTys ty = split [] ty ty
251 split args orig_ty (FunTy arg res) = split (arg:args) res res
252 split args orig_ty (NoteTy _ ty) = split args orig_ty ty
253 split args orig_ty ty = (reverse args, orig_ty)
255 splitFunTysN :: String -> Int -> Type -> ([Type], Type)
256 splitFunTysN msg orig_n orig_ty = split orig_n [] orig_ty orig_ty
258 split 0 args syn_ty ty = (reverse args, syn_ty)
259 split n args syn_ty (FunTy arg res) = split (n-1) (arg:args) res res
260 split n args syn_ty (NoteTy _ ty) = split n args syn_ty ty
261 split n args syn_ty ty = pprPanic ("splitFunTysN: " ++ msg) (int orig_n <+> pprType orig_ty)
263 zipFunTys :: Outputable a => [a] -> Type -> ([(a,Type)], Type)
264 zipFunTys orig_xs orig_ty = split [] orig_xs orig_ty orig_ty
266 split acc [] nty ty = (reverse acc, nty)
267 split acc (x:xs) nty (FunTy arg res) = split ((x,arg):acc) xs res res
268 split acc xs nty (NoteTy _ ty) = split acc xs nty ty
269 split acc (x:xs) nty ty = pprPanic "zipFunTys" (ppr orig_xs <+> pprType orig_ty)
271 funResultTy :: Type -> Type
272 funResultTy (FunTy arg res) = res
273 funResultTy (NoteTy _ ty) = funResultTy ty
274 funResultTy ty = pprPanic "funResultTy" (pprType ty)
276 funArgTy :: Type -> Type
277 funArgTy (FunTy arg res) = arg
278 funArgTy (NoteTy _ ty) = funArgTy ty
279 funArgTy ty = pprPanic "funArgTy" (pprType ty)
283 ---------------------------------------------------------------------
288 mkTyConApp :: TyCon -> [Type] -> Type
290 | isFunTyCon tycon && length tys == 2
292 (ty1:ty2:_) -> FunTy ty1 ty2
295 = ASSERT(not (isSynTyCon tycon))
298 mkTyConTy :: TyCon -> Type
299 mkTyConTy tycon = ASSERT( not (isSynTyCon tycon) )
302 -- splitTyConApp "looks through" synonyms, because they don't
303 -- mean a distinct type, but all other type-constructor applications
304 -- including functions are returned as Just ..
306 splitTyConApp_maybe :: Type -> Maybe (TyCon, [Type])
307 splitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
308 splitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [arg,res])
309 splitTyConApp_maybe (NoteTy _ ty) = splitTyConApp_maybe ty
310 splitTyConApp_maybe other = Nothing
312 -- splitAlgTyConApp_maybe looks for
313 -- *saturated* applications of *algebraic* data types
314 -- "Algebraic" => newtype, data type, or dictionary (not function types)
315 -- We return the constructors too.
317 splitAlgTyConApp_maybe :: Type -> Maybe (TyCon, [Type], [DataCon])
318 splitAlgTyConApp_maybe (TyConApp tc tys)
320 tyConArity tc == length tys = Just (tc, tys, tyConDataCons tc)
321 splitAlgTyConApp_maybe (NoteTy _ ty) = splitAlgTyConApp_maybe ty
322 splitAlgTyConApp_maybe other = Nothing
324 splitAlgTyConApp :: Type -> (TyCon, [Type], [DataCon])
325 -- Here the "algebraic" property is an *assertion*
326 splitAlgTyConApp (TyConApp tc tys) = ASSERT( isAlgTyCon tc && tyConArity tc == length tys )
327 (tc, tys, tyConDataCons tc)
328 splitAlgTyConApp (NoteTy _ ty) = splitAlgTyConApp ty
331 "Dictionary" types are just ordinary data types, but you can
332 tell from the type constructor whether it's a dictionary or not.
335 mkDictTy :: Class -> [Type] -> Type
336 mkDictTy clas tys = TyConApp (classTyCon clas) tys
338 mkDictTys :: ClassContext -> [Type]
339 mkDictTys cxt = [mkDictTy cls tys | (cls,tys) <- cxt]
341 mkPredTy :: PredType -> Type
342 mkPredTy (Class clas tys) = TyConApp (classTyCon clas) tys
343 mkPredTy (IParam n ty) = NoteTy (IPNote n) ty
345 splitPredTy_maybe :: Type -> Maybe PredType
346 splitPredTy_maybe (TyConApp tc tys)
347 | maybeToBool maybe_class
348 && tyConArity tc == length tys = Just (Class clas tys)
350 maybe_class = tyConClass_maybe tc
351 Just clas = maybe_class
353 splitPredTy_maybe (NoteTy (IPNote n) ty)
355 splitPredTy_maybe (NoteTy _ ty) = splitPredTy_maybe ty
356 splitPredTy_maybe other = Nothing
358 splitDictTy_maybe :: Type -> Maybe (Class, [Type])
360 = case splitPredTy_maybe ty of
361 Just p -> getClassTys_maybe p
364 isDictTy :: Type -> Bool
365 -- This version is slightly more efficient than (maybeToBool . splitDictTy)
366 isDictTy (TyConApp tc tys)
367 | maybeToBool (tyConClass_maybe tc)
368 && tyConArity tc == length tys
370 isDictTy (NoteTy _ ty) = isDictTy ty
371 isDictTy other = False
374 ---------------------------------------------------------------------
379 mkSynTy syn_tycon tys
380 = ASSERT( isSynTyCon syn_tycon )
381 ASSERT( isNotUsgTy body )
382 ASSERT( length tyvars == length tys )
383 NoteTy (SynNote (TyConApp syn_tycon tys))
384 (substTy (mkTyVarSubst tyvars tys) body)
386 (tyvars, body) = getSynTyConDefn syn_tycon
388 isSynTy (NoteTy (SynNote _) _) = True
389 isSynTy other = False
391 deNoteType :: Type -> Type
392 -- Sorry for the cute name
393 deNoteType ty@(TyVarTy tyvar) = ty
394 deNoteType (TyConApp tycon tys) = TyConApp tycon (map deNoteType tys)
395 deNoteType (NoteTy _ ty) = deNoteType ty
396 deNoteType (AppTy fun arg) = AppTy (deNoteType fun) (deNoteType arg)
397 deNoteType (FunTy fun arg) = FunTy (deNoteType fun) (deNoteType arg)
398 deNoteType (ForAllTy tv ty) = ForAllTy tv (deNoteType ty)
401 Notes on type synonyms
402 ~~~~~~~~~~~~~~~~~~~~~~
403 The various "split" functions (splitFunTy, splitRhoTy, splitForAllTy) try
404 to return type synonyms whereever possible. Thus
409 splitFunTys (a -> Foo a) = ([a], Foo a)
412 The reason is that we then get better (shorter) type signatures in
413 interfaces. Notably this plays a role in tcTySigs in TcBinds.lhs.
419 repType looks through
423 It's useful in the back end where we're not
424 interested in newtypes anymore.
427 repType :: Type -> Type
428 repType (ForAllTy _ ty) = repType ty
429 repType (NoteTy _ ty) = repType ty
430 repType ty = case splitNewType_maybe ty of
431 Just ty' -> repType ty' -- Still re-apply repType in case of for-all
434 splitRepFunTys :: Type -> ([Type], Type)
435 -- Like splitFunTys, but looks through newtypes and for-alls
436 splitRepFunTys ty = split [] (repType ty)
438 split args (FunTy arg res) = split (arg:args) (repType res)
439 split args ty = (reverse args, ty)
441 typePrimRep :: Type -> PrimRep
442 typePrimRep ty = case repType ty of
443 TyConApp tc _ -> tyConPrimRep tc
445 AppTy _ _ -> PtrRep -- ??
448 splitNewType_maybe :: Type -> Maybe Type
449 -- Find the representation of a newtype, if it is one
450 -- Looks through multiple levels of newtype, but does not look through for-alls
451 splitNewType_maybe (NoteTy _ ty) = splitNewType_maybe ty
452 splitNewType_maybe (TyConApp tc tys) = case newTyConRep tc of
453 Just rep_ty -> ASSERT( length tys == tyConArity tc )
454 -- The assert should hold because repType should
455 -- only be applied to *types* (of kind *)
456 Just (applyTys rep_ty tys)
458 splitNewType_maybe other = Nothing
463 ---------------------------------------------------------------------
467 NB: Invariant: if present, usage note is at the very top of the type.
468 This should be carefully preserved.
470 In some parts of the compiler, comments use the _Once Upon a
471 Polymorphic Type_ (POPL'99) usage of "rho = generalised
472 usage-annotated type; sigma = usage-annotated type; tau =
473 usage-annotated type except on top"; unfortunately this conflicts with
474 the rho/tau/theta/sigma usage in the rest of the compiler. (KSW
478 mkUsgTy :: UsageAnn -> Type -> Type
480 mkUsgTy UsMany ty = ASSERT2( isNotUsgTy ty, pprType ty )
483 mkUsgTy usg ty = ASSERT2( isNotUsgTy ty, pprType ty )
484 NoteTy (UsgNote usg) ty
486 -- The isUsgTy function is utterly useless if UsManys are omitted.
487 -- Be warned! KSW 1999-04.
488 isUsgTy :: Type -> Bool
492 isUsgTy (NoteTy (UsgForAll _) ty) = isUsgTy ty
493 isUsgTy (NoteTy (UsgNote _) _ ) = True
494 isUsgTy other = False
497 -- The isNotUsgTy function may return a false True if UsManys are omitted;
498 -- in other words, A SSERT( isNotUsgTy ty ) may be useful but
499 -- A SSERT( not (isNotUsg ty) ) is asking for trouble. KSW 1999-04.
500 isNotUsgTy :: Type -> Bool
501 isNotUsgTy (NoteTy (UsgForAll _) _) = False
502 isNotUsgTy (NoteTy (UsgNote _) _) = False
503 isNotUsgTy other = True
505 -- splitUsgTy_maybe is not exported, since it is meaningless if
506 -- UsManys are omitted. It is used in several places in this module,
507 -- however. KSW 1999-04.
508 splitUsgTy_maybe :: Type -> Maybe (UsageAnn,Type)
509 splitUsgTy_maybe (NoteTy (UsgNote usg) ty2) = ASSERT( isNotUsgTy ty2 )
511 splitUsgTy_maybe ty@(NoteTy (UsgForAll _) _) = pprPanic "splitUsgTy_maybe:" $ pprType ty
512 splitUsgTy_maybe ty = Nothing
514 splitUsgTy :: Type -> (UsageAnn,Type)
515 splitUsgTy ty = case splitUsgTy_maybe ty of
521 pprPanic "splitUsgTy: no usage annot:" $ pprType ty
524 tyUsg :: Type -> UsageAnn
525 tyUsg = fst . splitUsgTy
527 unUsgTy :: Type -> Type
528 -- strip outer usage annotation if present
529 unUsgTy ty = case splitUsgTy_maybe ty of
530 Just (_,ty1) -> ASSERT2( isNotUsgTy ty1, pprType ty )
534 mkUsForAllTy :: UVar -> Type -> Type
535 mkUsForAllTy uv ty = NoteTy (UsgForAll uv) ty
537 mkUsForAllTys :: [UVar] -> Type -> Type
538 mkUsForAllTys uvs ty = foldr (NoteTy . UsgForAll) ty uvs
540 splitUsForAllTys :: Type -> ([UVar],Type)
541 splitUsForAllTys ty = split ty []
542 where split (NoteTy (UsgForAll u) ty) uvs = split ty (u:uvs)
543 split other_ty uvs = (reverse uvs, other_ty)
545 substUsTy :: VarEnv UsageAnn -> Type -> Type
546 -- assumes range is fresh uvars, so no conflicts
547 substUsTy ve (NoteTy note@(UsgNote (UsVar u))
548 ty ) = NoteTy (case lookupVarEnv ve u of
549 Just ua -> UsgNote ua
552 substUsTy ve (NoteTy note@(UsgNote _) ty ) = NoteTy note (substUsTy ve ty)
553 substUsTy ve (NoteTy note@(UsgForAll _) ty ) = NoteTy note (substUsTy ve ty)
554 substUsTy ve (NoteTy (SynNote ty1) ty2) = NoteTy (SynNote (substUsTy ve ty1))
556 substUsTy ve (NoteTy note@(FTVNote _) ty ) = NoteTy note (substUsTy ve ty)
557 substUsTy ve ty@(TyVarTy _ ) = ty
558 substUsTy ve (AppTy ty1 ty2) = AppTy (substUsTy ve ty1)
560 substUsTy ve (FunTy ty1 ty2) = FunTy (substUsTy ve ty1)
562 substUsTy ve (TyConApp tyc tys) = TyConApp tyc (map (substUsTy ve) tys)
563 substUsTy ve (ForAllTy yv ty ) = ForAllTy yv (substUsTy ve ty)
567 ---------------------------------------------------------------------
571 We need to be clever here with usage annotations; they need to be
572 lifted or lowered through the forall as appropriate.
575 mkForAllTy :: TyVar -> Type -> Type
576 mkForAllTy tyvar ty = case splitUsgTy_maybe ty of
577 Just (usg,ty') -> NoteTy (UsgNote usg)
579 Nothing -> ForAllTy tyvar ty
581 mkForAllTys :: [TyVar] -> Type -> Type
582 mkForAllTys tyvars ty = case splitUsgTy_maybe ty of
583 Just (usg,ty') -> NoteTy (UsgNote usg)
584 (foldr ForAllTy ty' tyvars)
585 Nothing -> foldr ForAllTy ty tyvars
587 splitForAllTy_maybe :: Type -> Maybe (TyVar, Type)
588 splitForAllTy_maybe ty = case splitUsgTy_maybe ty of
589 Just (usg,ty') -> do (tyvar,ty'') <- splitFAT_m ty'
590 return (tyvar, NoteTy (UsgNote usg) ty'')
591 Nothing -> splitFAT_m ty
593 splitFAT_m (NoteTy _ ty) = splitFAT_m ty
594 splitFAT_m (ForAllTy tyvar ty) = Just(tyvar, ty)
595 splitFAT_m _ = Nothing
597 isForAllTy :: Type -> Bool
598 isForAllTy (NoteTy _ ty) = isForAllTy ty
599 isForAllTy (ForAllTy tyvar ty) = True
602 splitForAllTys :: Type -> ([TyVar], Type)
603 splitForAllTys ty = case splitUsgTy_maybe ty of
604 Just (usg,ty') -> let (tvs,ty'') = split ty' ty' []
605 in (tvs, NoteTy (UsgNote usg) ty'')
606 Nothing -> split ty ty []
608 split orig_ty (ForAllTy tv ty) tvs = split ty ty (tv:tvs)
609 split orig_ty (NoteTy _ ty) tvs = split orig_ty ty tvs
610 split orig_ty t tvs = (reverse tvs, orig_ty)
613 @mkPiType@ makes a (->) type or a forall type, depending on whether
614 it is given a type variable or a term variable.
617 mkPiType :: Var -> Type -> Type -- The more polymorphic version doesn't work...
618 mkPiType v ty | isId v = mkFunTy (idType v) ty
619 | otherwise = mkForAllTy v ty
622 Applying a for-all to its arguments
625 applyTy :: Type -> Type -> Type
626 applyTy (NoteTy note@(UsgNote _) fun) arg = NoteTy note (applyTy fun arg)
627 applyTy (NoteTy note@(UsgForAll _) fun) arg = NoteTy note (applyTy fun arg)
628 applyTy (NoteTy _ fun) arg = applyTy fun arg
629 applyTy (ForAllTy tv ty) arg = ASSERT( isNotUsgTy arg )
630 substTy (mkTyVarSubst [tv] [arg]) ty
631 applyTy other arg = panic "applyTy"
633 applyTys :: Type -> [Type] -> Type
634 applyTys fun_ty arg_tys
635 = substTy (mkTyVarSubst tvs arg_tys) ty
637 (tvs, ty) = split fun_ty arg_tys
639 split fun_ty [] = ([], fun_ty)
640 split (NoteTy note@(UsgNote _) fun_ty)
641 args = case split fun_ty args of
642 (tvs, ty) -> (tvs, NoteTy note ty)
643 split (NoteTy note@(UsgForAll _) fun_ty)
644 args = case split fun_ty args of
645 (tvs, ty) -> (tvs, NoteTy note ty)
646 split (NoteTy _ fun_ty) args = split fun_ty args
647 split (ForAllTy tv fun_ty) (arg:args) = ASSERT2( isNotUsgTy arg, vcat (map pprType arg_tys) $$
648 text "in application of" <+> pprType fun_ty)
649 case split fun_ty args of
650 (tvs, ty) -> (tv:tvs, ty)
651 split other_ty args = panic "applyTys"
654 Note that we allow applications to be of usage-annotated- types, as an
655 extension: we handle them by lifting the annotation outside. The
656 argument, however, must still be unannotated.
659 hoistForAllTys :: Type -> Type
660 -- Move all the foralls to the top
661 -- e.g. T -> forall a. a ==> forall a. T -> a
663 = case hoist ty of { (tvs, body) -> mkForAllTys tvs body }
665 hoist :: Type -> ([TyVar], Type)
666 hoist ty = case splitFunTys ty of { (args, res) ->
667 case splitForAllTys res of {
668 ([], body) -> ([], ty) ;
669 (tvs1, body1) -> case hoist body1 of { (tvs2,body2) ->
670 (tvs1 ++ tvs2, mkFunTys args body2)
675 %************************************************************************
677 \subsection{Stuff to do with the source-language types}
679 PredType and ThetaType are used in types for expressions and bindings.
680 ClassPred and ClassContext are used in class and instance declarations.
682 %************************************************************************
687 data PredType = Class Class [Type]
689 type ThetaType = [PredType]
690 type ClassPred = (Class, [Type])
691 type ClassContext = [ClassPred]
692 type SigmaType = Type
696 instance Outputable PredType where
701 mkClassPred clas tys = Class clas tys
703 getClassTys_maybe :: PredType -> Maybe ClassPred
704 getClassTys_maybe (Class clas tys) = Just (clas, tys)
705 getClassTys_maybe _ = Nothing
707 ipName_maybe :: PredType -> Maybe Name
708 ipName_maybe (IParam n _) = Just n
709 ipName_maybe _ = Nothing
711 classesToPreds cts = map (uncurry Class) cts
713 classesOfPreds theta = concatMap cvt theta
714 where cvt (Class clas tys) = [(clas, tys)]
715 cvt (IParam _ _ ) = []
718 @isTauTy@ tests for nested for-alls.
721 isTauTy :: Type -> Bool
722 isTauTy (TyVarTy v) = True
723 isTauTy (TyConApp _ tys) = all isTauTy tys
724 isTauTy (AppTy a b) = isTauTy a && isTauTy b
725 isTauTy (FunTy a b) = isTauTy a && isTauTy b
726 isTauTy (NoteTy _ ty) = isTauTy ty
727 isTauTy other = False
731 mkRhoTy :: [PredType] -> Type -> Type
732 mkRhoTy theta ty = foldr (\p r -> FunTy (mkPredTy p) r) ty theta
734 splitRhoTy :: Type -> ([PredType], Type)
735 splitRhoTy ty = split ty ty []
737 split orig_ty (FunTy arg res) ts = case splitPredTy_maybe arg of
738 Just p -> split res res (p:ts)
739 Nothing -> (reverse ts, orig_ty)
740 split orig_ty (NoteTy _ ty) ts = split orig_ty ty ts
741 split orig_ty ty ts = (reverse ts, orig_ty)
747 mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau)
749 splitSigmaTy :: Type -> ([TyVar], [PredType], Type)
753 (tyvars,rho) = splitForAllTys ty
754 (theta,tau) = splitRhoTy rho
758 %************************************************************************
760 \subsection{Kinds and free variables}
762 %************************************************************************
764 ---------------------------------------------------------------------
765 Finding the kind of a type
766 ~~~~~~~~~~~~~~~~~~~~~~~~~~
768 typeKind :: Type -> Kind
770 typeKind (TyVarTy tyvar) = tyVarKind tyvar
771 typeKind (TyConApp tycon tys) = foldr (\_ k -> funResultTy k) (tyConKind tycon) tys
772 typeKind (NoteTy _ ty) = typeKind ty
773 typeKind (AppTy fun arg) = funResultTy (typeKind fun)
775 typeKind (FunTy arg res) = boxedTypeKind -- A function is boxed regardless of its result type
776 -- No functions at the type level, hence we don't need
777 -- to say (typeKind res).
779 typeKind (ForAllTy tv ty) = typeKind ty
783 ---------------------------------------------------------------------
784 Free variables of a type
785 ~~~~~~~~~~~~~~~~~~~~~~~~
787 tyVarsOfType :: Type -> TyVarSet
789 tyVarsOfType (TyVarTy tv) = unitVarSet tv
790 tyVarsOfType (TyConApp tycon tys) = tyVarsOfTypes tys
791 tyVarsOfType (NoteTy (FTVNote tvs) ty2) = tvs
792 tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty1
793 tyVarsOfType (NoteTy (UsgNote _) ty) = tyVarsOfType ty
794 tyVarsOfType (NoteTy (UsgForAll _) ty) = tyVarsOfType ty
795 tyVarsOfType (NoteTy (IPNote _) ty) = tyVarsOfType ty
796 tyVarsOfType (FunTy arg res) = tyVarsOfType arg `unionVarSet` tyVarsOfType res
797 tyVarsOfType (AppTy fun arg) = tyVarsOfType fun `unionVarSet` tyVarsOfType arg
798 tyVarsOfType (ForAllTy tyvar ty) = tyVarsOfType ty `minusVarSet` unitVarSet tyvar
800 tyVarsOfTypes :: [Type] -> TyVarSet
801 tyVarsOfTypes tys = foldr (unionVarSet.tyVarsOfType) emptyVarSet tys
803 tyVarsOfPred :: PredType -> TyVarSet
804 tyVarsOfPred (Class clas tys) = tyVarsOfTypes tys
805 tyVarsOfPred (IParam n ty) = tyVarsOfType ty
807 tyVarsOfTheta :: ThetaType -> TyVarSet
808 tyVarsOfTheta = foldr (unionVarSet . tyVarsOfPred) emptyVarSet
810 -- Add a Note with the free tyvars to the top of the type
811 -- (but under a usage if there is one)
812 addFreeTyVars :: Type -> Type
813 addFreeTyVars (NoteTy note@(UsgNote _) ty) = NoteTy note (addFreeTyVars ty)
814 addFreeTyVars (NoteTy note@(UsgForAll _) ty) = NoteTy note (addFreeTyVars ty)
815 addFreeTyVars ty@(NoteTy (FTVNote _) _) = ty
816 addFreeTyVars ty = NoteTy (FTVNote (tyVarsOfType ty)) ty
818 -- Find the free names of a type, including the type constructors and classes it mentions
819 namesOfType :: Type -> NameSet
820 namesOfType (TyVarTy tv) = unitNameSet (getName tv)
821 namesOfType (TyConApp tycon tys) = unitNameSet (getName tycon) `unionNameSets`
823 namesOfType (NoteTy (SynNote ty1) ty2) = namesOfType ty1
824 namesOfType (NoteTy other_note ty2) = namesOfType ty2
825 namesOfType (FunTy arg res) = namesOfType arg `unionNameSets` namesOfType res
826 namesOfType (AppTy fun arg) = namesOfType fun `unionNameSets` namesOfType arg
827 namesOfType (ForAllTy tyvar ty) = namesOfType ty `minusNameSet` unitNameSet (getName tyvar)
829 namesOfTypes tys = foldr (unionNameSets . namesOfType) emptyNameSet tys
833 %************************************************************************
835 \subsection{TidyType}
837 %************************************************************************
839 tidyTy tidies up a type for printing in an error message, or in
842 It doesn't change the uniques at all, just the print names.
845 tidyTyVar :: TidyEnv -> TyVar -> (TidyEnv, TyVar)
846 tidyTyVar env@(tidy_env, subst) tyvar
847 = case lookupVarEnv subst tyvar of
849 Just tyvar' -> -- Already substituted
852 Nothing -> -- Make a new nice name for it
854 case tidyOccName tidy_env (getOccName name) of
855 (tidy', occ') -> -- New occname reqd
856 ((tidy', subst'), tyvar')
858 subst' = extendVarEnv subst tyvar tyvar'
859 tyvar' = setTyVarName tyvar name'
860 name' = mkLocalName (getUnique name) occ' noSrcLoc
861 -- Note: make a *user* tyvar, so it printes nicely
862 -- Could extract src loc, but no need.
864 name = tyVarName tyvar
866 tidyTyVars env tyvars = mapAccumL tidyTyVar env tyvars
868 tidyType :: TidyEnv -> Type -> Type
869 tidyType env@(tidy_env, subst) ty
872 go (TyVarTy tv) = case lookupVarEnv subst tv of
873 Nothing -> TyVarTy tv
874 Just tv' -> TyVarTy tv'
875 go (TyConApp tycon tys) = let args = map go tys
876 in args `seqList` TyConApp tycon args
877 go (NoteTy note ty) = (NoteTy SAPPLY (go_note note)) SAPPLY (go ty)
878 go (AppTy fun arg) = (AppTy SAPPLY (go fun)) SAPPLY (go arg)
879 go (FunTy fun arg) = (FunTy SAPPLY (go fun)) SAPPLY (go arg)
880 go (ForAllTy tv ty) = ForAllTy tvp SAPPLY (tidyType envp ty)
882 (envp, tvp) = tidyTyVar env tv
884 go_note (SynNote ty) = SynNote SAPPLY (go ty)
885 go_note note@(FTVNote ftvs) = note -- No need to tidy the free tyvars
886 go_note note@(UsgNote _) = note -- Usage annotation is already tidy
887 go_note note@(UsgForAll _) = note -- Uvar binder is already tidy
888 go_note (IPNote n) = IPNote (tidyIPName n)
890 tidyTypes env tys = map (tidyType env) tys
894 @tidyOpenType@ grabs the free type variables, tidies them
895 and then uses @tidyType@ to work over the type itself
898 tidyOpenType :: TidyEnv -> Type -> (TidyEnv, Type)
900 = (env', tidyType env' ty)
902 env' = foldl go env (varSetElems (tyVarsOfType ty))
903 go env tyvar = fst (tidyTyVar env tyvar)
905 tidyOpenTypes :: TidyEnv -> [Type] -> (TidyEnv, [Type])
906 tidyOpenTypes env tys = mapAccumL tidyOpenType env tys
908 tidyTopType :: Type -> Type
909 tidyTopType ty = tidyType emptyTidyEnv ty
913 tidyIPName :: Name -> Name
915 = mkLocalName (getUnique name) (getOccName name) noSrcLoc
919 %************************************************************************
921 \subsection{Boxedness and liftedness}
923 %************************************************************************
926 isUnboxedType :: Type -> Bool
927 isUnboxedType ty = not (isFollowableRep (typePrimRep ty))
929 isUnLiftedType :: Type -> Bool
930 -- isUnLiftedType returns True for forall'd unlifted types:
931 -- x :: forall a. Int#
932 -- I found bindings like these were getting floated to the top level.
933 -- They are pretty bogus types, mind you. It would be better never to
936 isUnLiftedType (ForAllTy tv ty) = isUnLiftedType ty
937 isUnLiftedType (NoteTy _ ty) = isUnLiftedType ty
938 isUnLiftedType (TyConApp tc _) = isUnLiftedTyCon tc
939 isUnLiftedType other = False
941 isUnboxedTupleType :: Type -> Bool
942 isUnboxedTupleType ty = case splitTyConApp_maybe ty of
943 Just (tc, ty_args) -> isUnboxedTupleTyCon tc
946 -- Should only be applied to *types*; hence the assert
947 isAlgType :: Type -> Bool
948 isAlgType ty = case splitTyConApp_maybe ty of
949 Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
953 -- Should only be applied to *types*; hence the assert
954 isDataType :: Type -> Bool
955 isDataType ty = case splitTyConApp_maybe ty of
956 Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
960 isNewType :: Type -> Bool
961 isNewType ty = case splitTyConApp_maybe ty of
962 Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
968 %************************************************************************
970 \subsection{Sequencing on types
972 %************************************************************************
975 seqType :: Type -> ()
976 seqType (TyVarTy tv) = tv `seq` ()
977 seqType (AppTy t1 t2) = seqType t1 `seq` seqType t2
978 seqType (FunTy t1 t2) = seqType t1 `seq` seqType t2
979 seqType (NoteTy note t2) = seqNote note `seq` seqType t2
980 seqType (TyConApp tc tys) = tc `seq` seqTypes tys
981 seqType (ForAllTy tv ty) = tv `seq` seqType ty
983 seqTypes :: [Type] -> ()
985 seqTypes (ty:tys) = seqType ty `seq` seqTypes tys
987 seqNote :: TyNote -> ()
988 seqNote (SynNote ty) = seqType ty
989 seqNote (FTVNote set) = sizeUniqSet set `seq` ()
990 seqNote (UsgNote usg) = usg `seq` ()
991 seqNote (IPNote nm) = nm `seq` ()