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 applyTy, applyTys, hoistForAllTys,
49 TauType, RhoType, SigmaType, PredType(..), ThetaType,
50 ClassPred, ClassContext, mkClassPred,
51 getClassTys_maybe, ipName_maybe, classesToPreds, classesOfPreds,
52 isTauTy, mkRhoTy, splitRhoTy,
53 mkSigmaTy, isSigmaTy, 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, ClassPred, ClassContext )
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 (IPNote _) ty) = Nothing
246 splitFunTy_maybe (NoteTy _ ty) = splitFunTy_maybe ty
247 splitFunTy_maybe other = Nothing
249 splitFunTys :: Type -> ([Type], Type)
250 splitFunTys ty = split [] ty ty
252 split args orig_ty (FunTy arg res) = split (arg:args) res res
253 split args orig_ty (NoteTy (IPNote _) ty)
254 = (reverse args, orig_ty)
255 split args orig_ty (NoteTy _ ty) = split args orig_ty ty
256 split args orig_ty ty = (reverse args, orig_ty)
258 splitFunTysN :: String -> Int -> Type -> ([Type], Type)
259 splitFunTysN msg orig_n orig_ty = split orig_n [] orig_ty orig_ty
261 split 0 args syn_ty ty = (reverse args, syn_ty)
262 split n args syn_ty (FunTy arg res) = split (n-1) (arg:args) res res
263 split n args syn_ty (NoteTy _ ty) = split n args syn_ty ty
264 split n args syn_ty ty = pprPanic ("splitFunTysN: " ++ msg) (int orig_n <+> pprType orig_ty)
266 zipFunTys :: Outputable a => [a] -> Type -> ([(a,Type)], Type)
267 zipFunTys orig_xs orig_ty = split [] orig_xs orig_ty orig_ty
269 split acc [] nty ty = (reverse acc, nty)
270 split acc (x:xs) nty (FunTy arg res) = split ((x,arg):acc) xs res res
271 split acc xs nty (NoteTy _ ty) = split acc xs nty ty
272 split acc (x:xs) nty ty = pprPanic "zipFunTys" (ppr orig_xs <+> pprType orig_ty)
274 funResultTy :: Type -> Type
275 funResultTy (FunTy arg res) = res
276 funResultTy (NoteTy _ ty) = funResultTy ty
277 funResultTy ty = pprPanic "funResultTy" (pprType ty)
279 funArgTy :: Type -> Type
280 funArgTy (FunTy arg res) = arg
281 funArgTy (NoteTy _ ty) = funArgTy ty
282 funArgTy ty = pprPanic "funArgTy" (pprType ty)
286 ---------------------------------------------------------------------
291 mkTyConApp :: TyCon -> [Type] -> Type
293 | isFunTyCon tycon && length tys == 2
295 (ty1:ty2:_) -> FunTy ty1 ty2
298 = ASSERT(not (isSynTyCon tycon))
301 mkTyConTy :: TyCon -> Type
302 mkTyConTy tycon = ASSERT( not (isSynTyCon tycon) )
305 -- splitTyConApp "looks through" synonyms, because they don't
306 -- mean a distinct type, but all other type-constructor applications
307 -- including functions are returned as Just ..
309 splitTyConApp_maybe :: Type -> Maybe (TyCon, [Type])
310 splitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
311 splitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [arg,res])
312 splitTyConApp_maybe (NoteTy _ ty) = splitTyConApp_maybe ty
313 splitTyConApp_maybe other = Nothing
315 -- splitAlgTyConApp_maybe looks for
316 -- *saturated* applications of *algebraic* data types
317 -- "Algebraic" => newtype, data type, or dictionary (not function types)
318 -- We return the constructors too, so there had better be some.
320 splitAlgTyConApp_maybe :: Type -> Maybe (TyCon, [Type], [DataCon])
321 splitAlgTyConApp_maybe (TyConApp tc tys)
323 tyConArity tc == length tys = Just (tc, tys, tyConDataCons tc)
324 splitAlgTyConApp_maybe (NoteTy (IPNote _) ty)
326 splitAlgTyConApp_maybe (NoteTy _ ty) = splitAlgTyConApp_maybe ty
327 splitAlgTyConApp_maybe other = Nothing
329 splitAlgTyConApp :: Type -> (TyCon, [Type], [DataCon])
330 -- Here the "algebraic" property is an *assertion*
331 splitAlgTyConApp (TyConApp tc tys) = ASSERT( isAlgTyCon tc && tyConArity tc == length tys )
332 (tc, tys, tyConDataCons tc)
333 splitAlgTyConApp (NoteTy _ ty) = splitAlgTyConApp ty
335 splitAlgTyConApp ty = pprPanic "splitAlgTyConApp" (pprType ty)
339 "Dictionary" types are just ordinary data types, but you can
340 tell from the type constructor whether it's a dictionary or not.
343 mkDictTy :: Class -> [Type] -> Type
344 mkDictTy clas tys = TyConApp (classTyCon clas) tys
346 mkDictTys :: ClassContext -> [Type]
347 mkDictTys cxt = [mkDictTy cls tys | (cls,tys) <- cxt]
349 mkPredTy :: PredType -> Type
350 mkPredTy (Class clas tys) = TyConApp (classTyCon clas) tys
351 mkPredTy (IParam n ty) = NoteTy (IPNote n) ty
353 splitPredTy_maybe :: Type -> Maybe PredType
354 splitPredTy_maybe (TyConApp tc tys)
355 | maybeToBool maybe_class
356 && tyConArity tc == length tys = Just (Class clas tys)
358 maybe_class = tyConClass_maybe tc
359 Just clas = maybe_class
361 splitPredTy_maybe (NoteTy (IPNote n) ty)
363 splitPredTy_maybe (NoteTy _ ty) = splitPredTy_maybe ty
364 splitPredTy_maybe other = Nothing
366 splitDictTy_maybe :: Type -> Maybe (Class, [Type])
368 = case splitPredTy_maybe ty of
369 Just p -> getClassTys_maybe p
372 isDictTy :: Type -> Bool
373 -- This version is slightly more efficient than (maybeToBool . splitDictTy)
374 isDictTy (TyConApp tc tys)
375 | maybeToBool (tyConClass_maybe tc)
376 && tyConArity tc == length tys
378 isDictTy (NoteTy _ ty) = isDictTy ty
379 isDictTy other = False
382 ---------------------------------------------------------------------
387 mkSynTy syn_tycon tys
388 = ASSERT( isSynTyCon syn_tycon )
389 ASSERT( isNotUsgTy body )
390 ASSERT( length tyvars == length tys )
391 NoteTy (SynNote (TyConApp syn_tycon tys))
392 (substTy (mkTyVarSubst tyvars tys) body)
394 (tyvars, body) = getSynTyConDefn syn_tycon
396 isSynTy (NoteTy (SynNote _) _) = True
397 isSynTy other = False
399 deNoteType :: Type -> Type
400 -- Sorry for the cute name
401 deNoteType ty@(TyVarTy tyvar) = ty
402 deNoteType (TyConApp tycon tys) = TyConApp tycon (map deNoteType tys)
403 deNoteType (NoteTy _ ty) = deNoteType ty
404 deNoteType (AppTy fun arg) = AppTy (deNoteType fun) (deNoteType arg)
405 deNoteType (FunTy fun arg) = FunTy (deNoteType fun) (deNoteType arg)
406 deNoteType (ForAllTy tv ty) = ForAllTy tv (deNoteType ty)
409 Notes on type synonyms
410 ~~~~~~~~~~~~~~~~~~~~~~
411 The various "split" functions (splitFunTy, splitRhoTy, splitForAllTy) try
412 to return type synonyms whereever possible. Thus
417 splitFunTys (a -> Foo a) = ([a], Foo a)
420 The reason is that we then get better (shorter) type signatures in
421 interfaces. Notably this plays a role in tcTySigs in TcBinds.lhs.
427 repType looks through
431 It's useful in the back end where we're not
432 interested in newtypes anymore.
435 repType :: Type -> Type
436 repType (ForAllTy _ ty) = repType ty
437 repType (NoteTy _ ty) = repType ty
438 repType ty = case splitNewType_maybe ty of
439 Just ty' -> repType ty' -- Still re-apply repType in case of for-all
442 splitRepFunTys :: Type -> ([Type], Type)
443 -- Like splitFunTys, but looks through newtypes and for-alls
444 splitRepFunTys ty = split [] (repType ty)
446 split args (FunTy arg res) = split (arg:args) (repType res)
447 split args ty = (reverse args, ty)
449 typePrimRep :: Type -> PrimRep
450 typePrimRep ty = case repType ty of
451 TyConApp tc _ -> tyConPrimRep tc
453 AppTy _ _ -> PtrRep -- ??
456 splitNewType_maybe :: Type -> Maybe Type
457 -- Find the representation of a newtype, if it is one
458 -- Looks through multiple levels of newtype, but does not look through for-alls
459 splitNewType_maybe (NoteTy (IPNote _) ty)
461 splitNewType_maybe (NoteTy _ ty) = splitNewType_maybe ty
462 splitNewType_maybe (TyConApp tc tys) = case newTyConRep tc of
463 Just rep_ty -> ASSERT( length tys == tyConArity tc )
464 -- The assert should hold because repType should
465 -- only be applied to *types* (of kind *)
466 Just (applyTys rep_ty tys)
468 splitNewType_maybe other = Nothing
473 ---------------------------------------------------------------------
477 NB: Invariant: if present, usage note is at the very top of the type.
478 This should be carefully preserved.
480 In some parts of the compiler, comments use the _Once Upon a
481 Polymorphic Type_ (POPL'99) usage of "rho = generalised
482 usage-annotated type; sigma = usage-annotated type; tau =
483 usage-annotated type except on top"; unfortunately this conflicts with
484 the rho/tau/theta/sigma usage in the rest of the compiler. (KSW
488 mkUsgTy :: UsageAnn -> Type -> Type
490 mkUsgTy UsMany ty = ASSERT2( isNotUsgTy ty, pprType ty )
493 mkUsgTy usg ty = ASSERT2( isNotUsgTy ty, pprType ty )
494 NoteTy (UsgNote usg) ty
496 -- The isUsgTy function is utterly useless if UsManys are omitted.
497 -- Be warned! KSW 1999-04.
498 isUsgTy :: Type -> Bool
502 isUsgTy (NoteTy (UsgForAll _) ty) = isUsgTy ty
503 isUsgTy (NoteTy (UsgNote _) _ ) = True
504 isUsgTy other = False
507 -- The isNotUsgTy function may return a false True if UsManys are omitted;
508 -- in other words, A SSERT( isNotUsgTy ty ) may be useful but
509 -- A SSERT( not (isNotUsg ty) ) is asking for trouble. KSW 1999-04.
510 isNotUsgTy :: Type -> Bool
511 isNotUsgTy (NoteTy (UsgForAll _) _) = False
512 isNotUsgTy (NoteTy (UsgNote _) _) = False
513 isNotUsgTy other = True
515 -- splitUsgTy_maybe is not exported, since it is meaningless if
516 -- UsManys are omitted. It is used in several places in this module,
517 -- however. KSW 1999-04.
518 splitUsgTy_maybe :: Type -> Maybe (UsageAnn,Type)
519 splitUsgTy_maybe (NoteTy (UsgNote usg) ty2) = ASSERT( isNotUsgTy ty2 )
521 splitUsgTy_maybe ty@(NoteTy (UsgForAll _) _) = pprPanic "splitUsgTy_maybe:" $ pprType ty
522 splitUsgTy_maybe ty = Nothing
524 splitUsgTy :: Type -> (UsageAnn,Type)
525 splitUsgTy ty = case splitUsgTy_maybe ty of
531 pprPanic "splitUsgTy: no usage annot:" $ pprType ty
534 tyUsg :: Type -> UsageAnn
535 tyUsg = fst . splitUsgTy
537 unUsgTy :: Type -> Type
538 -- strip outer usage annotation if present
539 unUsgTy ty = case splitUsgTy_maybe ty of
540 Just (_,ty1) -> ASSERT2( isNotUsgTy ty1, pprType ty )
544 mkUsForAllTy :: UVar -> Type -> Type
545 mkUsForAllTy uv ty = NoteTy (UsgForAll uv) ty
547 mkUsForAllTys :: [UVar] -> Type -> Type
548 mkUsForAllTys uvs ty = foldr (NoteTy . UsgForAll) ty uvs
550 splitUsForAllTys :: Type -> ([UVar],Type)
551 splitUsForAllTys ty = split ty []
552 where split (NoteTy (UsgForAll u) ty) uvs = split ty (u:uvs)
553 split other_ty uvs = (reverse uvs, other_ty)
555 substUsTy :: VarEnv UsageAnn -> Type -> Type
556 -- assumes range is fresh uvars, so no conflicts
557 substUsTy ve (NoteTy note@(UsgNote (UsVar u))
558 ty ) = NoteTy (case lookupVarEnv ve u of
559 Just ua -> UsgNote ua
562 substUsTy ve (NoteTy note@(UsgNote _) ty ) = NoteTy note (substUsTy ve ty)
563 substUsTy ve (NoteTy note@(UsgForAll _) ty ) = NoteTy note (substUsTy ve ty)
564 substUsTy ve (NoteTy (SynNote ty1) ty2) = NoteTy (SynNote (substUsTy ve ty1))
566 substUsTy ve (NoteTy note@(FTVNote _) ty ) = NoteTy note (substUsTy ve ty)
567 substUsTy ve ty@(TyVarTy _ ) = ty
568 substUsTy ve (AppTy ty1 ty2) = AppTy (substUsTy ve ty1)
570 substUsTy ve (FunTy ty1 ty2) = FunTy (substUsTy ve ty1)
572 substUsTy ve (TyConApp tyc tys) = TyConApp tyc (map (substUsTy ve) tys)
573 substUsTy ve (ForAllTy yv ty ) = ForAllTy yv (substUsTy ve ty)
577 ---------------------------------------------------------------------
581 We need to be clever here with usage annotations; they need to be
582 lifted or lowered through the forall as appropriate.
585 mkForAllTy :: TyVar -> Type -> Type
586 mkForAllTy tyvar ty = case splitUsgTy_maybe ty of
587 Just (usg,ty') -> NoteTy (UsgNote usg)
589 Nothing -> ForAllTy tyvar ty
591 mkForAllTys :: [TyVar] -> Type -> Type
592 mkForAllTys tyvars ty = case splitUsgTy_maybe ty of
593 Just (usg,ty') -> NoteTy (UsgNote usg)
594 (foldr ForAllTy ty' tyvars)
595 Nothing -> foldr ForAllTy ty tyvars
597 splitForAllTy_maybe :: Type -> Maybe (TyVar, Type)
598 splitForAllTy_maybe ty = case splitUsgTy_maybe ty of
599 Just (usg,ty') -> do (tyvar,ty'') <- splitFAT_m ty'
600 return (tyvar, NoteTy (UsgNote usg) ty'')
601 Nothing -> splitFAT_m ty
603 splitFAT_m (NoteTy (IPNote _) ty) = Nothing
604 splitFAT_m (NoteTy _ ty) = splitFAT_m ty
605 splitFAT_m (ForAllTy tyvar ty) = Just(tyvar, ty)
606 splitFAT_m _ = Nothing
608 splitForAllTys :: Type -> ([TyVar], Type)
609 splitForAllTys ty = case splitUsgTy_maybe ty of
610 Just (usg,ty') -> let (tvs,ty'') = split ty' ty' []
611 in (tvs, NoteTy (UsgNote usg) ty'')
612 Nothing -> split ty ty []
614 split orig_ty (ForAllTy tv ty) tvs = split ty ty (tv:tvs)
615 split orig_ty (NoteTy (IPNote _) ty) tvs = (reverse tvs, orig_ty)
616 split orig_ty (NoteTy _ ty) tvs = split orig_ty ty tvs
617 split orig_ty t tvs = (reverse tvs, orig_ty)
620 -- (mkPiType now in CoreUtils)
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 %************************************************************************
685 data PredType = Class Class [Type]
689 type ThetaType = [PredType]
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 (IPNote _) ty) = False
727 isTauTy (NoteTy _ ty) = isTauTy ty
728 isTauTy other = False
732 mkRhoTy :: [PredType] -> Type -> Type
733 mkRhoTy theta ty = foldr (\p r -> FunTy (mkPredTy p) r) ty theta
735 splitRhoTy :: Type -> ([PredType], Type)
736 splitRhoTy ty = split ty ty []
738 split orig_ty (FunTy arg res) ts = case splitPredTy_maybe arg of
739 Just p -> split res res (p:ts)
740 Nothing -> (reverse ts, orig_ty)
741 split orig_ty (NoteTy (IPNote _) ty) ts = (reverse ts, orig_ty)
742 split orig_ty (NoteTy _ ty) ts = split orig_ty ty ts
743 split orig_ty ty ts = (reverse ts, orig_ty)
749 mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau)
751 isSigmaTy :: Type -> Bool
752 isSigmaTy (FunTy a b) = isPredTy a
753 where isPredTy (NoteTy (IPNote _) _) = True
754 -- JRL could be a dict ty, but that would be polymorphic,
755 -- and thus there would have been an outer ForAllTy
757 isSigmaTy (NoteTy (IPNote _) _) = False
758 isSigmaTy (NoteTy _ ty) = isSigmaTy ty
759 isSigmaTy (ForAllTy tyvar ty) = True
762 splitSigmaTy :: Type -> ([TyVar], [PredType], Type)
766 (tyvars,rho) = splitForAllTys ty
767 (theta,tau) = splitRhoTy rho
771 %************************************************************************
773 \subsection{Kinds and free variables}
775 %************************************************************************
777 ---------------------------------------------------------------------
778 Finding the kind of a type
779 ~~~~~~~~~~~~~~~~~~~~~~~~~~
781 typeKind :: Type -> Kind
783 typeKind (TyVarTy tyvar) = tyVarKind tyvar
784 typeKind (TyConApp tycon tys) = foldr (\_ k -> funResultTy k) (tyConKind tycon) tys
785 typeKind (NoteTy _ ty) = typeKind ty
786 typeKind (AppTy fun arg) = funResultTy (typeKind fun)
788 typeKind (FunTy arg res) = boxedTypeKind -- A function is boxed regardless of its result type
789 -- No functions at the type level, hence we don't need
790 -- to say (typeKind res).
792 typeKind (ForAllTy tv ty) = typeKind ty
796 ---------------------------------------------------------------------
797 Free variables of a type
798 ~~~~~~~~~~~~~~~~~~~~~~~~
800 tyVarsOfType :: Type -> TyVarSet
802 tyVarsOfType (TyVarTy tv) = unitVarSet tv
803 tyVarsOfType (TyConApp tycon tys) = tyVarsOfTypes tys
804 tyVarsOfType (NoteTy (FTVNote tvs) ty2) = tvs
805 tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty1
806 tyVarsOfType (NoteTy (UsgNote _) ty) = tyVarsOfType ty
807 tyVarsOfType (NoteTy (UsgForAll _) ty) = tyVarsOfType ty
808 tyVarsOfType (NoteTy (IPNote _) ty) = tyVarsOfType ty
809 tyVarsOfType (FunTy arg res) = tyVarsOfType arg `unionVarSet` tyVarsOfType res
810 tyVarsOfType (AppTy fun arg) = tyVarsOfType fun `unionVarSet` tyVarsOfType arg
811 tyVarsOfType (ForAllTy tyvar ty) = tyVarsOfType ty `minusVarSet` unitVarSet tyvar
813 tyVarsOfTypes :: [Type] -> TyVarSet
814 tyVarsOfTypes tys = foldr (unionVarSet.tyVarsOfType) emptyVarSet tys
816 tyVarsOfPred :: PredType -> TyVarSet
817 tyVarsOfPred (Class clas tys) = tyVarsOfTypes tys
818 tyVarsOfPred (IParam n ty) = tyVarsOfType ty
820 tyVarsOfTheta :: ThetaType -> TyVarSet
821 tyVarsOfTheta = foldr (unionVarSet . tyVarsOfPred) emptyVarSet
823 -- Add a Note with the free tyvars to the top of the type
824 -- (but under a usage if there is one)
825 addFreeTyVars :: Type -> Type
826 addFreeTyVars (NoteTy note@(UsgNote _) ty) = NoteTy note (addFreeTyVars ty)
827 addFreeTyVars (NoteTy note@(UsgForAll _) ty) = NoteTy note (addFreeTyVars ty)
828 addFreeTyVars ty@(NoteTy (FTVNote _) _) = ty
829 addFreeTyVars ty = NoteTy (FTVNote (tyVarsOfType ty)) ty
831 -- Find the free names of a type, including the type constructors and classes it mentions
832 namesOfType :: Type -> NameSet
833 namesOfType (TyVarTy tv) = unitNameSet (getName tv)
834 namesOfType (TyConApp tycon tys) = unitNameSet (getName tycon) `unionNameSets`
836 namesOfType (NoteTy (SynNote ty1) ty2) = namesOfType ty1
837 namesOfType (NoteTy other_note ty2) = namesOfType ty2
838 namesOfType (FunTy arg res) = namesOfType arg `unionNameSets` namesOfType res
839 namesOfType (AppTy fun arg) = namesOfType fun `unionNameSets` namesOfType arg
840 namesOfType (ForAllTy tyvar ty) = namesOfType ty `minusNameSet` unitNameSet (getName tyvar)
842 namesOfTypes tys = foldr (unionNameSets . namesOfType) emptyNameSet tys
846 %************************************************************************
848 \subsection{TidyType}
850 %************************************************************************
852 tidyTy tidies up a type for printing in an error message, or in
855 It doesn't change the uniques at all, just the print names.
858 tidyTyVar :: TidyEnv -> TyVar -> (TidyEnv, TyVar)
859 tidyTyVar env@(tidy_env, subst) tyvar
860 = case lookupVarEnv subst tyvar of
862 Just tyvar' -> -- Already substituted
865 Nothing -> -- Make a new nice name for it
867 case tidyOccName tidy_env (getOccName name) of
868 (tidy', occ') -> -- New occname reqd
869 ((tidy', subst'), tyvar')
871 subst' = extendVarEnv subst tyvar tyvar'
872 tyvar' = setTyVarName tyvar name'
873 name' = mkLocalName (getUnique name) occ' noSrcLoc
874 -- Note: make a *user* tyvar, so it printes nicely
875 -- Could extract src loc, but no need.
877 name = tyVarName tyvar
879 tidyTyVars env tyvars = mapAccumL tidyTyVar env tyvars
881 tidyType :: TidyEnv -> Type -> Type
882 tidyType env@(tidy_env, subst) ty
885 go (TyVarTy tv) = case lookupVarEnv subst tv of
886 Nothing -> TyVarTy tv
887 Just tv' -> TyVarTy tv'
888 go (TyConApp tycon tys) = let args = map go tys
889 in args `seqList` TyConApp tycon args
890 go (NoteTy note ty) = (NoteTy SAPPLY (go_note note)) SAPPLY (go ty)
891 go (AppTy fun arg) = (AppTy SAPPLY (go fun)) SAPPLY (go arg)
892 go (FunTy fun arg) = (FunTy SAPPLY (go fun)) SAPPLY (go arg)
893 go (ForAllTy tv ty) = ForAllTy tvp SAPPLY (tidyType envp ty)
895 (envp, tvp) = tidyTyVar env tv
897 go_note (SynNote ty) = SynNote SAPPLY (go ty)
898 go_note note@(FTVNote ftvs) = note -- No need to tidy the free tyvars
899 go_note note@(UsgNote _) = note -- Usage annotation is already tidy
900 go_note note@(UsgForAll _) = note -- Uvar binder is already tidy
901 go_note (IPNote n) = IPNote (tidyIPName n)
903 tidyTypes env tys = map (tidyType env) tys
907 @tidyOpenType@ grabs the free type variables, tidies them
908 and then uses @tidyType@ to work over the type itself
911 tidyOpenType :: TidyEnv -> Type -> (TidyEnv, Type)
913 = (env', tidyType env' ty)
915 env' = foldl go env (varSetElems (tyVarsOfType ty))
916 go env tyvar = fst (tidyTyVar env tyvar)
918 tidyOpenTypes :: TidyEnv -> [Type] -> (TidyEnv, [Type])
919 tidyOpenTypes env tys = mapAccumL tidyOpenType env tys
921 tidyTopType :: Type -> Type
922 tidyTopType ty = tidyType emptyTidyEnv ty
926 tidyIPName :: Name -> Name
928 = mkLocalName (getUnique name) (getOccName name) noSrcLoc
932 %************************************************************************
934 \subsection{Boxedness and liftedness}
936 %************************************************************************
939 isUnboxedType :: Type -> Bool
940 isUnboxedType ty = not (isFollowableRep (typePrimRep ty))
942 isUnLiftedType :: Type -> Bool
943 -- isUnLiftedType returns True for forall'd unlifted types:
944 -- x :: forall a. Int#
945 -- I found bindings like these were getting floated to the top level.
946 -- They are pretty bogus types, mind you. It would be better never to
949 isUnLiftedType (ForAllTy tv ty) = isUnLiftedType ty
950 isUnLiftedType (NoteTy _ ty) = isUnLiftedType ty
951 isUnLiftedType (TyConApp tc _) = isUnLiftedTyCon tc
952 isUnLiftedType other = False
954 isUnboxedTupleType :: Type -> Bool
955 isUnboxedTupleType ty = case splitTyConApp_maybe ty of
956 Just (tc, ty_args) -> isUnboxedTupleTyCon tc
959 -- Should only be applied to *types*; hence the assert
960 isAlgType :: Type -> Bool
961 isAlgType ty = case splitTyConApp_maybe ty of
962 Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
966 -- Should only be applied to *types*; hence the assert
967 isDataType :: Type -> Bool
968 isDataType ty = case splitTyConApp_maybe ty of
969 Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
973 isNewType :: Type -> Bool
974 isNewType ty = case splitTyConApp_maybe ty of
975 Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
981 %************************************************************************
983 \subsection{Sequencing on types
985 %************************************************************************
988 seqType :: Type -> ()
989 seqType (TyVarTy tv) = tv `seq` ()
990 seqType (AppTy t1 t2) = seqType t1 `seq` seqType t2
991 seqType (FunTy t1 t2) = seqType t1 `seq` seqType t2
992 seqType (NoteTy note t2) = seqNote note `seq` seqType t2
993 seqType (TyConApp tc tys) = tc `seq` seqTypes tys
994 seqType (ForAllTy tv ty) = tv `seq` seqType ty
996 seqTypes :: [Type] -> ()
998 seqTypes (ty:tys) = seqType ty `seq` seqTypes tys
1000 seqNote :: TyNote -> ()
1001 seqNote (SynNote ty) = seqType ty
1002 seqNote (FTVNote set) = sizeUniqSet set `seq` ()
1003 seqNote (UsgNote usg) = usg `seq` ()
1004 seqNote (IPNote nm) = nm `seq` ()