2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcType]{Types used in the typechecker}
6 This module provides the Type interface for front-end parts of the
9 * treat "source types" as opaque:
10 newtypes, and predicates are meaningful.
11 * look through usage types
13 The "tc" prefix is for "typechechecker", because the type checker
14 is the principal client.
18 --------------------------------
20 TcType, TcSigmaType, TcRhoType, TcTauType, TcPredType, TcThetaType,
21 TcTyVar, TcTyVarSet, TcKind,
23 BoxyTyVar, BoxySigmaType, BoxyRhoType, BoxyThetaType, BoxyType,
25 --------------------------------
27 UserTypeCtxt(..), pprUserTypeCtxt,
28 TcTyVarDetails(..), BoxInfo(..), pprTcTyVarDetails,
29 MetaDetails(Flexi, Indirect), SkolemInfo(..), pprSkolTvBinding, pprSkolInfo,
30 isImmutableTyVar, isSkolemTyVar, isMetaTyVar, isBoxyTyVar, isSigTyVar, isExistentialTyVar,
34 --------------------------------
38 --------------------------------
40 -- These are important because they do not look through newtypes
42 tcSplitForAllTys, tcSplitPhiTy,
43 tcSplitFunTy_maybe, tcSplitFunTys, tcFunArgTy, tcFunResultTy, tcSplitFunTysN,
44 tcSplitTyConApp, tcSplitTyConApp_maybe, tcTyConAppTyCon, tcTyConAppArgs,
45 tcSplitAppTy_maybe, tcSplitAppTy, tcSplitAppTys, repSplitAppTy_maybe,
46 tcValidInstHeadTy, tcGetTyVar_maybe, tcGetTyVar,
47 tcSplitSigmaTy, tcMultiSplitSigmaTy,
49 ---------------------------------
51 -- Again, newtypes are opaque
52 tcEqType, tcEqTypes, tcEqPred, tcCmpType, tcCmpTypes, tcCmpPred, tcEqTypeX,
54 isSigmaTy, isOverloadedTy, isRigidTy, isBoxyTy,
55 isDoubleTy, isFloatTy, isIntTy, isStringTy,
56 isIntegerTy, isBoolTy, isUnitTy,
57 isTauTy, isTauTyCon, tcIsTyVarTy, tcIsForAllTy,
59 ---------------------------------
60 -- Misc type manipulators
61 deNoteType, classesOfTheta,
62 tyClsNamesOfType, tyClsNamesOfDFunHead,
65 ---------------------------------
67 getClassPredTys_maybe, getClassPredTys,
68 isClassPred, isTyVarClassPred, isEqPred,
69 mkDictTy, tcSplitPredTy_maybe,
70 isPredTy, isDictTy, tcSplitDFunTy, tcSplitDFunHead, predTyUnique,
71 mkClassPred, isInheritablePred, isLinearPred, isIPPred, mkPredName,
72 dataConsStupidTheta, isRefineableTy,
74 ---------------------------------
75 -- Foreign import and export
76 isFFIArgumentTy, -- :: DynFlags -> Safety -> Type -> Bool
77 isFFIImportResultTy, -- :: DynFlags -> Type -> Bool
78 isFFIExportResultTy, -- :: Type -> Bool
79 isFFIExternalTy, -- :: Type -> Bool
80 isFFIDynArgumentTy, -- :: Type -> Bool
81 isFFIDynResultTy, -- :: Type -> Bool
82 isFFILabelTy, -- :: Type -> Bool
83 isFFIDotnetTy, -- :: DynFlags -> Type -> Bool
84 isFFIDotnetObjTy, -- :: Type -> Bool
85 isFFITy, -- :: Type -> Bool
86 tcSplitIOType_maybe, -- :: Type -> Maybe Type
87 toDNType, -- :: Type -> DNType
89 --------------------------------
90 -- Rexported from Type
91 Kind, -- Stuff to do with kinds is insensitive to pre/post Tc
92 unliftedTypeKind, liftedTypeKind, argTypeKind,
93 openTypeKind, mkArrowKind, mkArrowKinds,
94 isLiftedTypeKind, isUnliftedTypeKind, isSubOpenTypeKind,
95 isSubArgTypeKind, isSubKind, defaultKind,
96 kindVarRef, mkKindVar,
98 Type, PredType(..), ThetaType,
99 mkForAllTy, mkForAllTys,
100 mkFunTy, mkFunTys, zipFunTys,
101 mkTyConApp, mkAppTy, mkAppTys, applyTy, applyTys,
102 mkTyVarTy, mkTyVarTys, mkTyConTy, mkPredTy, mkPredTys,
104 -- Type substitutions
105 TvSubst(..), -- Representation visible to a few friends
106 TvSubstEnv, emptyTvSubst, substEqSpec,
107 mkOpenTvSubst, zipOpenTvSubst, zipTopTvSubst, mkTopTvSubst, notElemTvSubst,
108 getTvSubstEnv, setTvSubstEnv, getTvInScope, extendTvInScope, lookupTyVar,
109 extendTvSubst, extendTvSubstList, isInScope, mkTvSubst, zipTyEnv,
110 substTy, substTys, substTyWith, substTheta, substTyVar, substTyVarBndr,
112 isUnLiftedType, -- Source types are always lifted
113 isUnboxedTupleType, -- Ditto
116 tidyTopType, tidyType, tidyPred, tidyTypes, tidyFreeTyVars, tidyOpenType, tidyOpenTypes,
117 tidyTyVarBndr, tidyOpenTyVar, tidyOpenTyVars, tidySkolemTyVar,
120 tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta,
121 tcTyVarsOfType, tcTyVarsOfTypes, exactTyVarsOfType, exactTyVarsOfTypes,
123 pprKind, pprParendKind,
124 pprType, pprParendType, pprTyThingCategory,
125 pprPred, pprTheta, pprThetaArrow, pprClassPred
129 #include "HsVersions.h"
132 import TypeRep ( Type(..), funTyCon, Kind ) -- friend
134 import Type ( -- Re-exports
135 tyVarsOfType, tyVarsOfTypes, tyVarsOfPred,
136 tyVarsOfTheta, Kind, PredType(..), KindVar,
137 ThetaType, isUnliftedTypeKind, unliftedTypeKind,
139 liftedTypeKind, openTypeKind, mkArrowKind,
140 tySuperKind, isLiftedTypeKind,
141 mkArrowKinds, mkForAllTy, mkForAllTys,
142 defaultKind, isSubArgTypeKind, isSubOpenTypeKind,
143 mkFunTy, mkFunTys, zipFunTys,
145 mkAppTys, applyTy, applyTys,
146 mkTyVarTy, mkTyVarTys, mkTyConTy, mkPredTy,
147 mkPredTys, isUnLiftedType,
148 isUnboxedTupleType, isPrimitiveType,
150 tidyTopType, tidyType, tidyPred, tidyTypes,
151 tidyFreeTyVars, tidyOpenType, tidyOpenTypes,
152 tidyTyVarBndr, tidyOpenTyVar,
153 tidyOpenTyVars, tidyKind,
156 tcEqType, tcEqTypes, tcCmpType, tcCmpTypes,
157 tcEqPred, tcCmpPred, tcEqTypeX, eqKind,
160 TvSubstEnv, emptyTvSubst, mkTvSubst, zipTyEnv,
161 mkOpenTvSubst, zipOpenTvSubst, zipTopTvSubst, mkTopTvSubst,
162 getTvSubstEnv, setTvSubstEnv, getTvInScope, extendTvInScope,
163 extendTvSubst, extendTvSubstList, isInScope, notElemTvSubst,
164 substTy, substTys, substTyWith, substTheta,
165 substTyVar, substTyVarBndr, substPred, lookupTyVar,
167 typeKind, repType, coreView, repSplitAppTy_maybe,
168 pprKind, pprParendKind,
169 pprType, pprParendType, pprTyThingCategory,
170 pprPred, pprTheta, pprThetaArrow, pprClassPred
172 import TyCon ( TyCon, isUnLiftedTyCon, isSynTyCon, isOpenTyCon,
173 synTyConDefn, tyConUnique )
174 import DataCon ( DataCon, dataConStupidTheta, dataConResTys )
175 import Class ( Class )
176 import Var ( TyVar, Id, isCoVar, isTcTyVar, mkTcTyVar, tyVarName, tyVarKind, tcTyVarDetails )
177 import ForeignCall ( Safety, DNType(..) )
178 import Unify ( tcMatchTys )
182 import DynFlags ( DynFlags, DynFlag( Opt_GlasgowExts ), dopt )
183 import Name ( Name, NamedThing(..), mkInternalName, getSrcLoc, mkSystemName )
185 import VarEnv ( TidyEnv )
186 import OccName ( OccName, mkDictOcc, mkOccName, tvName )
187 import PrelNames -- Lots (e.g. in isFFIArgumentTy)
188 import TysWiredIn ( unitTyCon, charTyCon, listTyCon )
189 import BasicTypes ( IPName(..), Arity, ipNameName )
190 import SrcLoc ( SrcLoc, SrcSpan )
191 import Util ( equalLength )
192 import Maybes ( maybeToBool, expectJust, mapCatMaybes )
193 import ListSetOps ( hasNoDups )
194 import List ( nubBy )
200 %************************************************************************
204 %************************************************************************
206 The type checker divides the generic Type world into the
207 following more structured beasts:
209 sigma ::= forall tyvars. phi
210 -- A sigma type is a qualified type
212 -- Note that even if 'tyvars' is empty, theta
213 -- may not be: e.g. (?x::Int) => Int
215 -- Note that 'sigma' is in prenex form:
216 -- all the foralls are at the front.
217 -- A 'phi' type has no foralls to the right of
225 -- A 'tau' type has no quantification anywhere
226 -- Note that the args of a type constructor must be taus
228 | tycon tau_1 .. tau_n
232 -- In all cases, a (saturated) type synonym application is legal,
233 -- provided it expands to the required form.
236 type TcTyVar = TyVar -- Used only during type inference
237 type TcType = Type -- A TcType can have mutable type variables
238 -- Invariant on ForAllTy in TcTypes:
240 -- a cannot occur inside a MutTyVar in T; that is,
241 -- T is "flattened" before quantifying over a
243 -- These types do not have boxy type variables in them
244 type TcPredType = PredType
245 type TcThetaType = ThetaType
246 type TcSigmaType = TcType
247 type TcRhoType = TcType
248 type TcTauType = TcType
250 type TcTyVarSet = TyVarSet
252 -- These types may have boxy type variables in them
253 type BoxyTyVar = TcTyVar
254 type BoxyRhoType = TcType
255 type BoxyThetaType = TcThetaType
256 type BoxySigmaType = TcType
257 type BoxyType = TcType
261 %************************************************************************
263 \subsection{TyVarDetails}
265 %************************************************************************
267 TyVarDetails gives extra info about type variables, used during type
268 checking. It's attached to mutable type variables only.
269 It's knot-tied back to Var.lhs. There is no reason in principle
270 why Var.lhs shouldn't actually have the definition, but it "belongs" here.
273 Note [Signature skolems]
274 ~~~~~~~~~~~~~~~~~~~~~~~~
279 (x,y,z) = ([y,z], z, head x)
281 Here, x and y have type sigs, which go into the environment. We used to
282 instantiate their types with skolem constants, and push those types into
283 the RHS, so we'd typecheck the RHS with type
285 where a*, b* are skolem constants, and c is an ordinary meta type varible.
287 The trouble is that the occurrences of z in the RHS force a* and b* to
288 be the *same*, so we can't make them into skolem constants that don't unify
289 with each other. Alas.
291 One solution would be insist that in the above defn the programmer uses
292 the same type variable in both type signatures. But that takes explanation.
294 The alternative (currently implemented) is to have a special kind of skolem
295 constant, SigTv, which can unify with other SigTvs. These are *not* treated
296 as righd for the purposes of GADTs. And they are used *only* for pattern
297 bindings and mutually recursive function bindings. See the function
298 TcBinds.tcInstSig, and its use_skols parameter.
302 -- A TyVarDetails is inside a TyVar
304 = SkolemTv SkolemInfo -- A skolem constant
306 | MetaTv BoxInfo (IORef MetaDetails)
309 = BoxTv -- The contents is a (non-boxy) sigma-type
310 -- That is, this MetaTv is a "box"
312 | TauTv -- The contents is a (non-boxy) tau-type
313 -- That is, this MetaTv is an ordinary unification variable
315 | SigTv SkolemInfo -- A variant of TauTv, except that it should not be
316 -- unified with a type, only with a type variable
317 -- SigTvs are only distinguished to improve error messages
318 -- see Note [Signature skolems]
319 -- The MetaDetails, if filled in, will
320 -- always be another SigTv or a SkolemTv
323 -- A TauTv is always filled in with a tau-type, which
324 -- never contains any BoxTvs, nor any ForAlls
326 -- However, a BoxTv can contain a type that contains further BoxTvs
327 -- Notably, when typechecking an explicit list, say [e1,e2], with
328 -- expected type being a box b1, we fill in b1 with (List b2), where
329 -- b2 is another (currently empty) box.
332 = Flexi -- Flexi type variables unify to become
335 | Indirect TcType -- INVARIANT:
336 -- For a BoxTv, this type must be non-boxy
337 -- For a TauTv, this type must be a tau-type
340 = SigSkol UserTypeCtxt -- A skolem that is created by instantiating
341 -- a programmer-supplied type signature
342 -- Location of the binding site is on the TyVar
344 -- The rest are for non-scoped skolems
345 | ClsSkol Class -- Bound at a class decl
346 | InstSkol Id -- Bound at an instance decl
347 | FamInstSkol TyCon -- Bound at a family instance decl
348 | PatSkol DataCon -- An existential type variable bound by a pattern for
349 SrcSpan -- a data constructor with an existential type. E.g.
350 -- data T = forall a. Eq a => MkT a
352 -- The pattern MkT x will allocate an existential type
354 | ArrowSkol SrcSpan -- An arrow form (see TcArrows)
356 | GenSkol [TcTyVar] -- Bound when doing a subsumption check for
357 TcType -- (forall tvs. ty)
360 | UnkSkol -- Unhelpful info (until I improve it)
362 -------------------------------------
363 -- UserTypeCtxt describes the places where a
364 -- programmer-written type signature can occur
366 = FunSigCtxt Name -- Function type signature
367 -- Also used for types in SPECIALISE pragmas
368 | ExprSigCtxt -- Expression type signature
369 | ConArgCtxt Name -- Data constructor argument
370 | TySynCtxt Name -- RHS of a type synonym decl
371 | GenPatCtxt -- Pattern in generic decl
372 -- f{| a+b |} (Inl x) = ...
373 | LamPatSigCtxt -- Type sig in lambda pattern
375 | BindPatSigCtxt -- Type sig in pattern binding pattern
377 | ResSigCtxt -- Result type sig
379 | ForSigCtxt Name -- Foreign inport or export signature
380 | RuleSigCtxt Name -- Signature on a forall'd variable in a RULE
381 | DefaultDeclCtxt -- Types in a default declaration
382 | SpecInstCtxt -- SPECIALISE instance pragma
384 -- Notes re TySynCtxt
385 -- We allow type synonyms that aren't types; e.g. type List = []
387 -- If the RHS mentions tyvars that aren't in scope, we'll
388 -- quantify over them:
389 -- e.g. type T = a->a
390 -- will become type T = forall a. a->a
392 -- With gla-exts that's right, but for H98 we should complain.
394 ---------------------------------
397 mkKindName :: Unique -> Name
398 mkKindName unique = mkSystemName unique kind_var_occ
400 kindVarRef :: KindVar -> IORef MetaDetails
402 case tcTyVarDetails tc of
403 MetaTv TauTv ref -> ref
404 other -> pprPanic "kindVarRef" (ppr tc)
406 mkKindVar :: Unique -> IORef MetaDetails -> KindVar
408 = mkTcTyVar (mkKindName u)
409 tySuperKind -- not sure this is right,
410 -- do we need kind vars for
414 kind_var_occ :: OccName -- Just one for all KindVars
415 -- They may be jiggled by tidying
416 kind_var_occ = mkOccName tvName "k"
420 %************************************************************************
424 %************************************************************************
427 pprTcTyVarDetails :: TcTyVarDetails -> SDoc
429 pprTcTyVarDetails (SkolemTv _) = ptext SLIT("sk")
430 pprTcTyVarDetails (MetaTv BoxTv _) = ptext SLIT("box")
431 pprTcTyVarDetails (MetaTv TauTv _) = ptext SLIT("tau")
432 pprTcTyVarDetails (MetaTv (SigTv _) _) = ptext SLIT("sig")
434 pprUserTypeCtxt :: UserTypeCtxt -> SDoc
435 pprUserTypeCtxt (FunSigCtxt n) = ptext SLIT("the type signature for") <+> quotes (ppr n)
436 pprUserTypeCtxt ExprSigCtxt = ptext SLIT("an expression type signature")
437 pprUserTypeCtxt (ConArgCtxt c) = ptext SLIT("the type of the constructor") <+> quotes (ppr c)
438 pprUserTypeCtxt (TySynCtxt c) = ptext SLIT("the RHS of the type synonym") <+> quotes (ppr c)
439 pprUserTypeCtxt GenPatCtxt = ptext SLIT("the type pattern of a generic definition")
440 pprUserTypeCtxt LamPatSigCtxt = ptext SLIT("a pattern type signature")
441 pprUserTypeCtxt BindPatSigCtxt = ptext SLIT("a pattern type signature")
442 pprUserTypeCtxt ResSigCtxt = ptext SLIT("a result type signature")
443 pprUserTypeCtxt (ForSigCtxt n) = ptext SLIT("the foreign declaration for") <+> quotes (ppr n)
444 pprUserTypeCtxt (RuleSigCtxt n) = ptext SLIT("the type signature for") <+> quotes (ppr n)
445 pprUserTypeCtxt DefaultDeclCtxt = ptext SLIT("a type in a `default' declaration")
446 pprUserTypeCtxt SpecInstCtxt = ptext SLIT("a SPECIALISE instance pragma")
449 --------------------------------
450 tidySkolemTyVar :: TidyEnv -> TcTyVar -> (TidyEnv, TcTyVar)
451 -- Tidy the type inside a GenSkol, preparatory to printing it
452 tidySkolemTyVar env tv
453 = ASSERT( isSkolemTyVar tv || isSigTyVar tv )
454 (env1, mkTcTyVar (tyVarName tv) (tyVarKind tv) info1)
456 (env1, info1) = case tcTyVarDetails tv of
457 SkolemTv info -> (env1, SkolemTv info')
459 (env1, info') = tidy_skol_info env info
460 MetaTv (SigTv info) box -> (env1, MetaTv (SigTv info') box)
462 (env1, info') = tidy_skol_info env info
465 tidy_skol_info env (GenSkol tvs ty loc) = (env2, GenSkol tvs1 ty1 loc)
467 (env1, tvs1) = tidyOpenTyVars env tvs
468 (env2, ty1) = tidyOpenType env1 ty
469 tidy_skol_info env info = (env, info)
471 pprSkolTvBinding :: TcTyVar -> SDoc
472 -- Print info about the binding of a skolem tyvar,
473 -- or nothing if we don't have anything useful to say
475 = ppr_details (tcTyVarDetails tv)
477 ppr_details (MetaTv TauTv _) = quotes (ppr tv) <+> ptext SLIT("is a meta type variable")
478 ppr_details (MetaTv BoxTv _) = quotes (ppr tv) <+> ptext SLIT("is a boxy type variable")
479 ppr_details (MetaTv (SigTv info) _) = ppr_skol info
480 ppr_details (SkolemTv info) = ppr_skol info
482 ppr_skol UnkSkol = empty -- Unhelpful; omit
483 ppr_skol (SigSkol ctxt) = sep [quotes (ppr tv) <+> ptext SLIT("is bound by") <+> pprUserTypeCtxt ctxt,
484 nest 2 (ptext SLIT("at") <+> ppr (getSrcLoc tv))]
485 ppr_skol info = quotes (ppr tv) <+> pprSkolInfo info
487 pprSkolInfo :: SkolemInfo -> SDoc
488 pprSkolInfo (SigSkol ctxt) = ptext SLIT("is bound by") <+> pprUserTypeCtxt ctxt
489 pprSkolInfo (ClsSkol cls) = ptext SLIT("is bound by the class declaration for") <+> quotes (ppr cls)
490 pprSkolInfo (InstSkol df) =
491 ptext SLIT("is bound by the instance declaration at") <+> ppr (getSrcLoc df)
492 pprSkolInfo (FamInstSkol tc) =
493 ptext SLIT("is bound by the family instance declaration at") <+>
495 pprSkolInfo (ArrowSkol loc) =
496 ptext SLIT("is bound by the arrow form at") <+> ppr loc
497 pprSkolInfo (PatSkol dc loc) = sep [ptext SLIT("is bound by the pattern for") <+> quotes (ppr dc),
498 nest 2 (ptext SLIT("at") <+> ppr loc)]
499 pprSkolInfo (GenSkol tvs ty loc) = sep [sep [ptext SLIT("is bound by the polymorphic type"),
500 nest 2 (quotes (ppr (mkForAllTys tvs ty)))],
501 nest 2 (ptext SLIT("at") <+> ppr loc)]
503 -- For type variables the others are dealt with by pprSkolTvBinding.
504 -- For Insts, these cases should not happen
505 pprSkolInfo UnkSkol = panic "UnkSkol"
507 instance Outputable MetaDetails where
508 ppr Flexi = ptext SLIT("Flexi")
509 ppr (Indirect ty) = ptext SLIT("Indirect") <+> ppr ty
513 %************************************************************************
517 %************************************************************************
520 isImmutableTyVar, isSkolemTyVar, isExistentialTyVar, isBoxyTyVar, isMetaTyVar :: TyVar -> Bool
522 | isTcTyVar tv = isSkolemTyVar tv
526 = ASSERT( isTcTyVar tv )
527 case tcTyVarDetails tv of
531 isExistentialTyVar tv -- Existential type variable, bound by a pattern
532 = ASSERT( isTcTyVar tv )
533 case tcTyVarDetails tv of
534 SkolemTv (PatSkol _ _) -> True
538 = ASSERT2( isTcTyVar tv, ppr tv )
539 case tcTyVarDetails tv of
544 = ASSERT( isTcTyVar tv )
545 case tcTyVarDetails tv of
546 MetaTv BoxTv _ -> True
550 = ASSERT( isTcTyVar tv )
551 case tcTyVarDetails tv of
552 MetaTv (SigTv _) _ -> True
555 metaTvRef :: TyVar -> IORef MetaDetails
557 = ASSERT( isTcTyVar tv )
558 case tcTyVarDetails tv of
560 other -> pprPanic "metaTvRef" (ppr tv)
562 isFlexi, isIndirect :: MetaDetails -> Bool
564 isFlexi other = False
566 isIndirect (Indirect _) = True
567 isIndirect other = False
571 %************************************************************************
573 \subsection{Tau, sigma and rho}
575 %************************************************************************
578 mkSigmaTy :: [TyVar] -> [PredType] -> Type -> Type
579 mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkPhiTy theta tau)
581 mkPhiTy :: [PredType] -> Type -> Type
582 mkPhiTy theta ty = foldr (\p r -> FunTy (mkPredTy p) r) ty theta
585 @isTauTy@ tests for nested for-alls. It should not be called on a boxy type.
588 isTauTy :: Type -> Bool
589 isTauTy ty | Just ty' <- tcView ty = isTauTy ty'
590 isTauTy (TyVarTy tv) = ASSERT( not (isTcTyVar tv && isBoxyTyVar tv) )
592 isTauTy (TyConApp tc tys) = all isTauTy tys && isTauTyCon tc
593 isTauTy (AppTy a b) = isTauTy a && isTauTy b
594 isTauTy (FunTy a b) = isTauTy a && isTauTy b
595 isTauTy (PredTy p) = True -- Don't look through source types
596 isTauTy other = False
599 isTauTyCon :: TyCon -> Bool
600 -- Returns False for type synonyms whose expansion is a polytype
602 | isSynTyCon tc && not (isOpenTyCon tc) = isTauTy (snd (synTyConDefn tc))
606 isBoxyTy :: TcType -> Bool
607 isBoxyTy ty = any isBoxyTyVar (varSetElems (tcTyVarsOfType ty))
609 isRigidTy :: TcType -> Bool
610 -- A type is rigid if it has no meta type variables in it
611 isRigidTy ty = all isSkolemTyVar (varSetElems (tcTyVarsOfType ty))
613 isRefineableTy :: TcType -> Bool
614 -- A type should have type refinements applied to it if it has
615 -- free type variables, and they are all rigid
616 isRefineableTy ty = not (null tc_tvs) && all isSkolemTyVar tc_tvs
618 tc_tvs = varSetElems (tcTyVarsOfType ty)
621 getDFunTyKey :: Type -> OccName -- Get some string from a type, to be used to
622 -- construct a dictionary function name
623 getDFunTyKey ty | Just ty' <- tcView ty = getDFunTyKey ty'
624 getDFunTyKey (TyVarTy tv) = getOccName tv
625 getDFunTyKey (TyConApp tc _) = getOccName tc
626 getDFunTyKey (AppTy fun _) = getDFunTyKey fun
627 getDFunTyKey (FunTy arg _) = getOccName funTyCon
628 getDFunTyKey (ForAllTy _ t) = getDFunTyKey t
629 getDFunTyKey ty = pprPanic "getDFunTyKey" (pprType ty)
630 -- PredTy shouldn't happen
634 %************************************************************************
636 \subsection{Expanding and splitting}
638 %************************************************************************
640 These tcSplit functions are like their non-Tc analogues, but
641 a) they do not look through newtypes
642 b) they do not look through PredTys
643 c) [future] they ignore usage-type annotations
645 However, they are non-monadic and do not follow through mutable type
646 variables. It's up to you to make sure this doesn't matter.
649 tcSplitForAllTys :: Type -> ([TyVar], Type)
650 tcSplitForAllTys ty = split ty ty []
652 split orig_ty ty tvs | Just ty' <- tcView ty = split orig_ty ty' tvs
653 split orig_ty (ForAllTy tv ty) tvs
654 | not (isCoVar tv) = split ty ty (tv:tvs)
655 split orig_ty t tvs = (reverse tvs, orig_ty)
657 tcIsForAllTy ty | Just ty' <- tcView ty = tcIsForAllTy ty'
658 tcIsForAllTy (ForAllTy tv ty) = not (isCoVar tv)
659 tcIsForAllTy t = False
661 tcSplitPhiTy :: Type -> (ThetaType, Type)
662 tcSplitPhiTy ty = split ty ty []
664 split orig_ty ty tvs | Just ty' <- tcView ty = split orig_ty ty' tvs
666 split orig_ty (ForAllTy tv ty) ts
667 | isCoVar tv = split ty ty (eq_pred:ts)
669 PredTy eq_pred = tyVarKind tv
670 split orig_ty (FunTy arg res) ts
671 | Just p <- tcSplitPredTy_maybe arg = split res res (p:ts)
672 split orig_ty ty ts = (reverse ts, orig_ty)
674 tcSplitSigmaTy :: Type -> ([TyVar], ThetaType, Type)
675 tcSplitSigmaTy ty = case tcSplitForAllTys ty of
676 (tvs, rho) -> case tcSplitPhiTy rho of
677 (theta, tau) -> (tvs, theta, tau)
679 -----------------------
682 -> ( [([TyVar], ThetaType)], -- forall as.C => forall bs.D
683 TcSigmaType) -- The rest of the type
685 -- We need a loop here because we are now prepared to entertain
687 -- f:: forall a. Eq a => forall b. Baz b => tau
688 -- We want to instantiate this to
689 -- f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)}
691 tcMultiSplitSigmaTy sigma
692 = case (tcSplitSigmaTy sigma) of
693 ([],[],ty) -> ([], sigma)
694 (tvs, theta, ty) -> case tcMultiSplitSigmaTy ty of
695 (pairs, rest) -> ((tvs,theta):pairs, rest)
697 -----------------------
698 tcTyConAppTyCon :: Type -> TyCon
699 tcTyConAppTyCon ty = fst (tcSplitTyConApp ty)
701 tcTyConAppArgs :: Type -> [Type]
702 tcTyConAppArgs ty = snd (tcSplitTyConApp ty)
704 tcSplitTyConApp :: Type -> (TyCon, [Type])
705 tcSplitTyConApp ty = case tcSplitTyConApp_maybe ty of
707 Nothing -> pprPanic "tcSplitTyConApp" (pprType ty)
709 tcSplitTyConApp_maybe :: Type -> Maybe (TyCon, [Type])
710 tcSplitTyConApp_maybe ty | Just ty' <- tcView ty = tcSplitTyConApp_maybe ty'
711 tcSplitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
712 tcSplitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [arg,res])
713 -- Newtypes are opaque, so they may be split
714 -- However, predicates are not treated
715 -- as tycon applications by the type checker
716 tcSplitTyConApp_maybe other = Nothing
718 -----------------------
719 tcSplitFunTys :: Type -> ([Type], Type)
720 tcSplitFunTys ty = case tcSplitFunTy_maybe ty of
722 Just (arg,res) -> (arg:args, res')
724 (args,res') = tcSplitFunTys res
726 tcSplitFunTy_maybe :: Type -> Maybe (Type, Type)
727 tcSplitFunTy_maybe ty | Just ty' <- tcView ty = tcSplitFunTy_maybe ty'
728 tcSplitFunTy_maybe (FunTy arg res) = Just (arg, res)
729 tcSplitFunTy_maybe other = Nothing
733 -> Arity -- N: Number of desired args
734 -> ([TcSigmaType], -- Arg types (N or fewer)
735 TcSigmaType) -- The rest of the type
737 tcSplitFunTysN ty n_args
740 | Just (arg,res) <- tcSplitFunTy_maybe ty
741 = case tcSplitFunTysN res (n_args - 1) of
742 (args, res) -> (arg:args, res)
746 tcSplitFunTy ty = expectJust "tcSplitFunTy" (tcSplitFunTy_maybe ty)
747 tcFunArgTy ty = fst (tcSplitFunTy ty)
748 tcFunResultTy ty = snd (tcSplitFunTy ty)
750 -----------------------
751 tcSplitAppTy_maybe :: Type -> Maybe (Type, Type)
752 tcSplitAppTy_maybe ty | Just ty' <- tcView ty = tcSplitAppTy_maybe ty'
753 tcSplitAppTy_maybe ty = repSplitAppTy_maybe ty
755 tcSplitAppTy :: Type -> (Type, Type)
756 tcSplitAppTy ty = case tcSplitAppTy_maybe ty of
758 Nothing -> pprPanic "tcSplitAppTy" (pprType ty)
760 tcSplitAppTys :: Type -> (Type, [Type])
764 go ty args = case tcSplitAppTy_maybe ty of
765 Just (ty', arg) -> go ty' (arg:args)
768 -----------------------
769 tcGetTyVar_maybe :: Type -> Maybe TyVar
770 tcGetTyVar_maybe ty | Just ty' <- tcView ty = tcGetTyVar_maybe ty'
771 tcGetTyVar_maybe (TyVarTy tv) = Just tv
772 tcGetTyVar_maybe other = Nothing
774 tcGetTyVar :: String -> Type -> TyVar
775 tcGetTyVar msg ty = expectJust msg (tcGetTyVar_maybe ty)
777 tcIsTyVarTy :: Type -> Bool
778 tcIsTyVarTy ty = maybeToBool (tcGetTyVar_maybe ty)
780 -----------------------
781 tcSplitDFunTy :: Type -> ([TyVar], [PredType], Class, [Type])
782 -- Split the type of a dictionary function
784 = case tcSplitSigmaTy ty of { (tvs, theta, tau) ->
785 case tcSplitDFunHead tau of { (clas, tys) ->
786 (tvs, theta, clas, tys) }}
788 tcSplitDFunHead :: Type -> (Class, [Type])
790 = case tcSplitPredTy_maybe tau of
791 Just (ClassP clas tys) -> (clas, tys)
792 other -> panic "tcSplitDFunHead"
794 tcValidInstHeadTy :: Type -> Bool
795 -- Used in Haskell-98 mode, for the argument types of an instance head
796 -- These must not be type synonyms, but everywhere else type synonyms
797 -- are transparent, so we need a special function here
800 NoteTy _ ty -> tcValidInstHeadTy ty
801 TyConApp tc tys -> not (isSynTyCon tc) && ok tys
802 FunTy arg res -> ok [arg, res]
805 -- Check that all the types are type variables,
806 -- and that each is distinct
807 ok tys = equalLength tvs tys && hasNoDups tvs
809 tvs = mapCatMaybes get_tv tys
811 get_tv (NoteTy _ ty) = get_tv ty -- Again, do not look
812 get_tv (TyVarTy tv) = Just tv -- through synonyms
813 get_tv other = Nothing
818 %************************************************************************
820 \subsection{Predicate types}
822 %************************************************************************
825 tcSplitPredTy_maybe :: Type -> Maybe PredType
826 -- Returns Just for predicates only
827 tcSplitPredTy_maybe ty | Just ty' <- tcView ty = tcSplitPredTy_maybe ty'
828 tcSplitPredTy_maybe (PredTy p) = Just p
829 tcSplitPredTy_maybe other = Nothing
831 predTyUnique :: PredType -> Unique
832 predTyUnique (IParam n _) = getUnique (ipNameName n)
833 predTyUnique (ClassP clas tys) = getUnique clas
835 mkPredName :: Unique -> SrcLoc -> PredType -> Name
836 mkPredName uniq loc (ClassP cls tys) = mkInternalName uniq (mkDictOcc (getOccName cls)) loc
837 mkPredName uniq loc (IParam ip ty) = mkInternalName uniq (getOccName (ipNameName ip)) loc
841 --------------------- Dictionary types ---------------------------------
844 mkClassPred clas tys = ClassP clas tys
846 isClassPred :: PredType -> Bool
847 isClassPred (ClassP clas tys) = True
848 isClassPred other = False
850 isTyVarClassPred (ClassP clas tys) = all tcIsTyVarTy tys
851 isTyVarClassPred other = False
853 getClassPredTys_maybe :: PredType -> Maybe (Class, [Type])
854 getClassPredTys_maybe (ClassP clas tys) = Just (clas, tys)
855 getClassPredTys_maybe _ = Nothing
857 getClassPredTys :: PredType -> (Class, [Type])
858 getClassPredTys (ClassP clas tys) = (clas, tys)
859 getClassPredTys other = panic "getClassPredTys"
861 isEqPred :: PredType -> Bool
862 isEqPred (EqPred {}) = True
865 mkDictTy :: Class -> [Type] -> Type
866 mkDictTy clas tys = mkPredTy (ClassP clas tys)
868 isDictTy :: Type -> Bool
869 isDictTy ty | Just ty' <- tcView ty = isDictTy ty'
870 isDictTy (PredTy p) = isClassPred p
871 isDictTy other = False
874 --------------------- Implicit parameters ---------------------------------
877 isIPPred :: PredType -> Bool
878 isIPPred (IParam _ _) = True
879 isIPPred other = False
881 isInheritablePred :: PredType -> Bool
882 -- Can be inherited by a context. For example, consider
883 -- f x = let g y = (?v, y+x)
884 -- in (g 3 with ?v = 8,
886 -- The point is that g's type must be quantifed over ?v:
887 -- g :: (?v :: a) => a -> a
888 -- but it doesn't need to be quantified over the Num a dictionary
889 -- which can be free in g's rhs, and shared by both calls to g
890 isInheritablePred (ClassP _ _) = True
891 isInheritablePred other = False
893 isLinearPred :: TcPredType -> Bool
894 isLinearPred (IParam (Linear n) _) = True
895 isLinearPred other = False
898 --------------------- Equality predicates ---------------------------------
900 substEqSpec :: TvSubst -> [(TyVar,Type)] -> [(TcType,TcType)]
901 substEqSpec subst eq_spec = [ (substTyVar subst tv, substTy subst ty)
902 | (tv,ty) <- eq_spec]
905 --------------------- The stupid theta (sigh) ---------------------------------
908 dataConsStupidTheta :: [DataCon] -> ThetaType
909 -- Union the stupid thetas from all the specified constructors (non-empty)
910 -- All the constructors should have the same result type, modulo alpha conversion
911 -- The resulting ThetaType uses type variables from the *first* constructor in the list
913 -- It's here because it's used in MkId.mkRecordSelId, and in TcExpr
914 dataConsStupidTheta (con1:cons)
915 = nubBy tcEqPred all_preds
917 all_preds = dataConStupidTheta con1 ++ other_stupids
918 res_tys1 = dataConResTys con1
919 tvs1 = tyVarsOfTypes res_tys1
920 other_stupids = [ substPred subst pred
922 , let Just subst = tcMatchTys tvs1 res_tys1 (dataConResTys con)
923 , pred <- dataConStupidTheta con ]
924 dataConsStupidTheta [] = panic "dataConsStupidTheta"
928 %************************************************************************
930 \subsection{Predicates}
932 %************************************************************************
934 isSigmaTy returns true of any qualified type. It doesn't *necessarily* have
936 f :: (?x::Int) => Int -> Int
939 isSigmaTy :: Type -> Bool
940 isSigmaTy ty | Just ty' <- tcView ty = isSigmaTy ty'
941 isSigmaTy (ForAllTy tyvar ty) = True
942 isSigmaTy (FunTy a b) = isPredTy a
945 isOverloadedTy :: Type -> Bool
946 isOverloadedTy ty | Just ty' <- tcView ty = isOverloadedTy ty'
947 isOverloadedTy (ForAllTy tyvar ty) = isOverloadedTy ty
948 isOverloadedTy (FunTy a b) = isPredTy a
949 isOverloadedTy _ = False
951 isPredTy :: Type -> Bool -- Belongs in TcType because it does
952 -- not look through newtypes, or predtypes (of course)
953 isPredTy ty | Just ty' <- tcView ty = isPredTy ty'
954 isPredTy (PredTy sty) = True
959 isFloatTy = is_tc floatTyConKey
960 isDoubleTy = is_tc doubleTyConKey
961 isIntegerTy = is_tc integerTyConKey
962 isIntTy = is_tc intTyConKey
963 isBoolTy = is_tc boolTyConKey
964 isUnitTy = is_tc unitTyConKey
966 is_tc :: Unique -> Type -> Bool
967 -- Newtypes are opaque to this
968 is_tc uniq ty = case tcSplitTyConApp_maybe ty of
969 Just (tc, _) -> uniq == getUnique tc
974 %************************************************************************
978 %************************************************************************
981 deNoteType :: Type -> Type
982 -- Remove all *outermost* type synonyms and other notes
983 deNoteType ty | Just ty' <- tcView ty = deNoteType ty'
988 tcTyVarsOfType :: Type -> TcTyVarSet
989 -- Just the *TcTyVars* free in the type
990 -- (Types.tyVarsOfTypes finds all free TyVars)
991 tcTyVarsOfType (TyVarTy tv) = if isTcTyVar tv then unitVarSet tv
993 tcTyVarsOfType (TyConApp tycon tys) = tcTyVarsOfTypes tys
994 tcTyVarsOfType (NoteTy _ ty) = tcTyVarsOfType ty
995 tcTyVarsOfType (PredTy sty) = tcTyVarsOfPred sty
996 tcTyVarsOfType (FunTy arg res) = tcTyVarsOfType arg `unionVarSet` tcTyVarsOfType res
997 tcTyVarsOfType (AppTy fun arg) = tcTyVarsOfType fun `unionVarSet` tcTyVarsOfType arg
998 tcTyVarsOfType (ForAllTy tyvar ty) = (tcTyVarsOfType ty `delVarSet` tyvar)
999 `unionVarSet` tcTyVarsOfTyVar tyvar
1000 -- We do sometimes quantify over skolem TcTyVars
1002 tcTyVarsOfTyVar :: TcTyVar -> TyVarSet
1003 tcTyVarsOfTyVar tv | isCoVar tv = tcTyVarsOfType (tyVarKind tv)
1004 | otherwise = emptyVarSet
1006 tcTyVarsOfTypes :: [Type] -> TyVarSet
1007 tcTyVarsOfTypes tys = foldr (unionVarSet.tcTyVarsOfType) emptyVarSet tys
1009 tcTyVarsOfPred :: PredType -> TyVarSet
1010 tcTyVarsOfPred (IParam _ ty) = tcTyVarsOfType ty
1011 tcTyVarsOfPred (ClassP _ tys) = tcTyVarsOfTypes tys
1012 tcTyVarsOfPred (EqPred ty1 ty2) = tcTyVarsOfType ty1 `unionVarSet` tcTyVarsOfType ty2
1015 Note [Silly type synonym]
1016 ~~~~~~~~~~~~~~~~~~~~~~~~~
1019 What are the free tyvars of (T x)? Empty, of course!
1020 Here's the example that Ralf Laemmel showed me:
1021 foo :: (forall a. C u a -> C u a) -> u
1022 mappend :: Monoid u => u -> u -> u
1024 bar :: Monoid u => u
1025 bar = foo (\t -> t `mappend` t)
1026 We have to generalise at the arg to f, and we don't
1027 want to capture the constraint (Monad (C u a)) because
1028 it appears to mention a. Pretty silly, but it was useful to him.
1030 exactTyVarsOfType is used by the type checker to figure out exactly
1031 which type variables are mentioned in a type. It's also used in the
1032 smart-app checking code --- see TcExpr.tcIdApp
1035 exactTyVarsOfType :: TcType -> TyVarSet
1036 -- Find the free type variables (of any kind)
1037 -- but *expand* type synonyms. See Note [Silly type synonym] above.
1038 exactTyVarsOfType ty
1041 go ty | Just ty' <- tcView ty = go ty' -- This is the key line
1042 go (TyVarTy tv) = unitVarSet tv
1043 go (TyConApp tycon tys) = exactTyVarsOfTypes tys
1044 go (PredTy ty) = go_pred ty
1045 go (FunTy arg res) = go arg `unionVarSet` go res
1046 go (AppTy fun arg) = go fun `unionVarSet` go arg
1047 go (ForAllTy tyvar ty) = delVarSet (go ty) tyvar
1048 `unionVarSet` go_tv tyvar
1050 go_pred (IParam _ ty) = go ty
1051 go_pred (ClassP _ tys) = exactTyVarsOfTypes tys
1052 go_pred (EqPred ty1 ty2) = go ty1 `unionVarSet` go ty2
1054 go_tv tyvar | isCoVar tyvar = go (tyVarKind tyvar)
1055 | otherwise = emptyVarSet
1057 exactTyVarsOfTypes :: [TcType] -> TyVarSet
1058 exactTyVarsOfTypes tys = foldr (unionVarSet . exactTyVarsOfType) emptyVarSet tys
1061 Find the free tycons and classes of a type. This is used in the front
1062 end of the compiler.
1065 tyClsNamesOfType :: Type -> NameSet
1066 tyClsNamesOfType (TyVarTy tv) = emptyNameSet
1067 tyClsNamesOfType (TyConApp tycon tys) = unitNameSet (getName tycon) `unionNameSets` tyClsNamesOfTypes tys
1068 tyClsNamesOfType (NoteTy _ ty2) = tyClsNamesOfType ty2
1069 tyClsNamesOfType (PredTy (IParam n ty)) = tyClsNamesOfType ty
1070 tyClsNamesOfType (PredTy (ClassP cl tys)) = unitNameSet (getName cl) `unionNameSets` tyClsNamesOfTypes tys
1071 tyClsNamesOfType (PredTy (EqPred ty1 ty2)) = tyClsNamesOfType ty1 `unionNameSets` tyClsNamesOfType ty2
1072 tyClsNamesOfType (FunTy arg res) = tyClsNamesOfType arg `unionNameSets` tyClsNamesOfType res
1073 tyClsNamesOfType (AppTy fun arg) = tyClsNamesOfType fun `unionNameSets` tyClsNamesOfType arg
1074 tyClsNamesOfType (ForAllTy tyvar ty) = tyClsNamesOfType ty
1076 tyClsNamesOfTypes tys = foldr (unionNameSets . tyClsNamesOfType) emptyNameSet tys
1078 tyClsNamesOfDFunHead :: Type -> NameSet
1079 -- Find the free type constructors and classes
1080 -- of the head of the dfun instance type
1081 -- The 'dfun_head_type' is because of
1082 -- instance Foo a => Baz T where ...
1083 -- The decl is an orphan if Baz and T are both not locally defined,
1084 -- even if Foo *is* locally defined
1085 tyClsNamesOfDFunHead dfun_ty
1086 = case tcSplitSigmaTy dfun_ty of
1087 (tvs,_,head_ty) -> tyClsNamesOfType head_ty
1089 classesOfTheta :: ThetaType -> [Class]
1090 -- Looks just for ClassP things; maybe it should check
1091 classesOfTheta preds = [ c | ClassP c _ <- preds ]
1095 %************************************************************************
1097 \subsection[TysWiredIn-ext-type]{External types}
1099 %************************************************************************
1101 The compiler's foreign function interface supports the passing of a
1102 restricted set of types as arguments and results (the restricting factor
1106 tcSplitIOType_maybe :: Type -> Maybe (TyCon, Type)
1107 -- (isIOType t) returns (Just (IO,t')) if t is of the form (IO t'), or
1108 -- some newtype wrapping thereof
1109 -- returns Nothing otherwise
1110 tcSplitIOType_maybe ty
1111 | Just (io_tycon, [io_res_ty]) <- tcSplitTyConApp_maybe ty,
1112 -- This split absolutely has to be a tcSplit, because we must
1113 -- see the IO type; and it's a newtype which is transparent to splitTyConApp.
1114 io_tycon `hasKey` ioTyConKey
1115 = Just (io_tycon, io_res_ty)
1117 | Just ty' <- coreView ty -- Look through non-recursive newtypes
1118 = tcSplitIOType_maybe ty'
1123 isFFITy :: Type -> Bool
1124 -- True for any TyCon that can possibly be an arg or result of an FFI call
1125 isFFITy ty = checkRepTyCon legalFFITyCon ty
1127 isFFIArgumentTy :: DynFlags -> Safety -> Type -> Bool
1128 -- Checks for valid argument type for a 'foreign import'
1129 isFFIArgumentTy dflags safety ty
1130 = checkRepTyCon (legalOutgoingTyCon dflags safety) ty
1132 isFFIExternalTy :: Type -> Bool
1133 -- Types that are allowed as arguments of a 'foreign export'
1134 isFFIExternalTy ty = checkRepTyCon legalFEArgTyCon ty
1136 isFFIImportResultTy :: DynFlags -> Type -> Bool
1137 isFFIImportResultTy dflags ty
1138 = checkRepTyCon (legalFIResultTyCon dflags) ty
1140 isFFIExportResultTy :: Type -> Bool
1141 isFFIExportResultTy ty = checkRepTyCon legalFEResultTyCon ty
1143 isFFIDynArgumentTy :: Type -> Bool
1144 -- The argument type of a foreign import dynamic must be Ptr, FunPtr, Addr,
1145 -- or a newtype of either.
1146 isFFIDynArgumentTy = checkRepTyConKey [ptrTyConKey, funPtrTyConKey]
1148 isFFIDynResultTy :: Type -> Bool
1149 -- The result type of a foreign export dynamic must be Ptr, FunPtr, Addr,
1150 -- or a newtype of either.
1151 isFFIDynResultTy = checkRepTyConKey [ptrTyConKey, funPtrTyConKey]
1153 isFFILabelTy :: Type -> Bool
1154 -- The type of a foreign label must be Ptr, FunPtr, Addr,
1155 -- or a newtype of either.
1156 isFFILabelTy = checkRepTyConKey [ptrTyConKey, funPtrTyConKey]
1158 isFFIDotnetTy :: DynFlags -> Type -> Bool
1159 isFFIDotnetTy dflags ty
1160 = checkRepTyCon (\ tc -> (legalFIResultTyCon dflags tc ||
1161 isFFIDotnetObjTy ty || isStringTy ty)) ty
1163 -- Support String as an argument or result from a .NET FFI call.
1165 case tcSplitTyConApp_maybe (repType ty) of
1167 | tc == listTyCon ->
1168 case tcSplitTyConApp_maybe (repType arg_ty) of
1169 Just (cc,[]) -> cc == charTyCon
1173 -- Support String as an argument or result from a .NET FFI call.
1174 isFFIDotnetObjTy ty =
1176 (_, t_ty) = tcSplitForAllTys ty
1178 case tcSplitTyConApp_maybe (repType t_ty) of
1179 Just (tc, [arg_ty]) | getName tc == objectTyConName -> True
1182 toDNType :: Type -> DNType
1184 | isStringTy ty = DNString
1185 | isFFIDotnetObjTy ty = DNObject
1186 | Just (tc,argTys) <- tcSplitTyConApp_maybe ty
1187 = case lookup (getUnique tc) dn_assoc of
1190 | tc `hasKey` ioTyConKey -> toDNType (head argTys)
1191 | otherwise -> pprPanic ("toDNType: unsupported .NET type")
1192 (pprType ty <+> parens (hcat (map pprType argTys)) <+> ppr tc)
1193 | otherwise = panic "toDNType" -- Is this right?
1195 dn_assoc :: [ (Unique, DNType) ]
1196 dn_assoc = [ (unitTyConKey, DNUnit)
1197 , (intTyConKey, DNInt)
1198 , (int8TyConKey, DNInt8)
1199 , (int16TyConKey, DNInt16)
1200 , (int32TyConKey, DNInt32)
1201 , (int64TyConKey, DNInt64)
1202 , (wordTyConKey, DNInt)
1203 , (word8TyConKey, DNWord8)
1204 , (word16TyConKey, DNWord16)
1205 , (word32TyConKey, DNWord32)
1206 , (word64TyConKey, DNWord64)
1207 , (floatTyConKey, DNFloat)
1208 , (doubleTyConKey, DNDouble)
1209 , (ptrTyConKey, DNPtr)
1210 , (funPtrTyConKey, DNPtr)
1211 , (charTyConKey, DNChar)
1212 , (boolTyConKey, DNBool)
1215 checkRepTyCon :: (TyCon -> Bool) -> Type -> Bool
1216 -- Look through newtypes
1217 -- Non-recursive ones are transparent to splitTyConApp,
1218 -- but recursive ones aren't. Manuel had:
1219 -- newtype T = MkT (Ptr T)
1220 -- and wanted it to work...
1221 checkRepTyCon check_tc ty
1222 | Just (tc,_) <- splitTyConApp_maybe (repType ty) = check_tc tc
1225 checkRepTyConKey :: [Unique] -> Type -> Bool
1226 -- Like checkRepTyCon, but just looks at the TyCon key
1227 checkRepTyConKey keys
1228 = checkRepTyCon (\tc -> tyConUnique tc `elem` keys)
1231 ----------------------------------------------
1232 These chaps do the work; they are not exported
1233 ----------------------------------------------
1236 legalFEArgTyCon :: TyCon -> Bool
1238 -- It's illegal to make foreign exports that take unboxed
1239 -- arguments. The RTS API currently can't invoke such things. --SDM 7/2000
1240 = boxedMarshalableTyCon tc
1242 legalFIResultTyCon :: DynFlags -> TyCon -> Bool
1243 legalFIResultTyCon dflags tc
1244 | tc == unitTyCon = True
1245 | otherwise = marshalableTyCon dflags tc
1247 legalFEResultTyCon :: TyCon -> Bool
1248 legalFEResultTyCon tc
1249 | tc == unitTyCon = True
1250 | otherwise = boxedMarshalableTyCon tc
1252 legalOutgoingTyCon :: DynFlags -> Safety -> TyCon -> Bool
1253 -- Checks validity of types going from Haskell -> external world
1254 legalOutgoingTyCon dflags safety tc
1255 = marshalableTyCon dflags tc
1257 legalFFITyCon :: TyCon -> Bool
1258 -- True for any TyCon that can possibly be an arg or result of an FFI call
1260 = isUnLiftedTyCon tc || boxedMarshalableTyCon tc || tc == unitTyCon
1262 marshalableTyCon dflags tc
1263 = (dopt Opt_GlasgowExts dflags && isUnLiftedTyCon tc)
1264 || boxedMarshalableTyCon tc
1266 boxedMarshalableTyCon tc
1267 = getUnique tc `elem` [ intTyConKey, int8TyConKey, int16TyConKey
1268 , int32TyConKey, int64TyConKey
1269 , wordTyConKey, word8TyConKey, word16TyConKey
1270 , word32TyConKey, word64TyConKey
1271 , floatTyConKey, doubleTyConKey
1272 , ptrTyConKey, funPtrTyConKey