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 | PatSkol DataCon -- An existential type variable bound by a pattern for
348 SrcSpan -- a data constructor with an existential type. E.g.
349 -- data T = forall a. Eq a => MkT a
351 -- The pattern MkT x will allocate an existential type
353 | ArrowSkol SrcSpan -- An arrow form (see TcArrows)
355 | GenSkol [TcTyVar] -- Bound when doing a subsumption check for
356 TcType -- (forall tvs. ty)
359 | UnkSkol -- Unhelpful info (until I improve it)
361 -------------------------------------
362 -- UserTypeCtxt describes the places where a
363 -- programmer-written type signature can occur
365 = FunSigCtxt Name -- Function type signature
366 -- Also used for types in SPECIALISE pragmas
367 | ExprSigCtxt -- Expression type signature
368 | ConArgCtxt Name -- Data constructor argument
369 | TySynCtxt Name -- RHS of a type synonym decl
370 | GenPatCtxt -- Pattern in generic decl
371 -- f{| a+b |} (Inl x) = ...
372 | LamPatSigCtxt -- Type sig in lambda pattern
374 | BindPatSigCtxt -- Type sig in pattern binding pattern
376 | ResSigCtxt -- Result type sig
378 | ForSigCtxt Name -- Foreign inport or export signature
379 | RuleSigCtxt Name -- Signature on a forall'd variable in a RULE
380 | DefaultDeclCtxt -- Types in a default declaration
381 | SpecInstCtxt -- SPECIALISE instance pragma
383 -- Notes re TySynCtxt
384 -- We allow type synonyms that aren't types; e.g. type List = []
386 -- If the RHS mentions tyvars that aren't in scope, we'll
387 -- quantify over them:
388 -- e.g. type T = a->a
389 -- will become type T = forall a. a->a
391 -- With gla-exts that's right, but for H98 we should complain.
393 ---------------------------------
396 mkKindName :: Unique -> Name
397 mkKindName unique = mkSystemName unique kind_var_occ
399 kindVarRef :: KindVar -> IORef MetaDetails
401 case tcTyVarDetails tc of
402 MetaTv TauTv ref -> ref
403 other -> pprPanic "kindVarRef" (ppr tc)
405 mkKindVar :: Unique -> IORef MetaDetails -> KindVar
407 = mkTcTyVar (mkKindName u)
408 tySuperKind -- not sure this is right,
409 -- do we need kind vars for
413 kind_var_occ :: OccName -- Just one for all KindVars
414 -- They may be jiggled by tidying
415 kind_var_occ = mkOccName tvName "k"
419 %************************************************************************
423 %************************************************************************
426 pprTcTyVarDetails :: TcTyVarDetails -> SDoc
428 pprTcTyVarDetails (SkolemTv _) = ptext SLIT("sk")
429 pprTcTyVarDetails (MetaTv BoxTv _) = ptext SLIT("box")
430 pprTcTyVarDetails (MetaTv TauTv _) = ptext SLIT("tau")
431 pprTcTyVarDetails (MetaTv (SigTv _) _) = ptext SLIT("sig")
433 pprUserTypeCtxt :: UserTypeCtxt -> SDoc
434 pprUserTypeCtxt (FunSigCtxt n) = ptext SLIT("the type signature for") <+> quotes (ppr n)
435 pprUserTypeCtxt ExprSigCtxt = ptext SLIT("an expression type signature")
436 pprUserTypeCtxt (ConArgCtxt c) = ptext SLIT("the type of the constructor") <+> quotes (ppr c)
437 pprUserTypeCtxt (TySynCtxt c) = ptext SLIT("the RHS of the type synonym") <+> quotes (ppr c)
438 pprUserTypeCtxt GenPatCtxt = ptext SLIT("the type pattern of a generic definition")
439 pprUserTypeCtxt LamPatSigCtxt = ptext SLIT("a pattern type signature")
440 pprUserTypeCtxt BindPatSigCtxt = ptext SLIT("a pattern type signature")
441 pprUserTypeCtxt ResSigCtxt = ptext SLIT("a result type signature")
442 pprUserTypeCtxt (ForSigCtxt n) = ptext SLIT("the foreign declaration for") <+> quotes (ppr n)
443 pprUserTypeCtxt (RuleSigCtxt n) = ptext SLIT("the type signature for") <+> quotes (ppr n)
444 pprUserTypeCtxt DefaultDeclCtxt = ptext SLIT("a type in a `default' declaration")
445 pprUserTypeCtxt SpecInstCtxt = ptext SLIT("a SPECIALISE instance pragma")
448 --------------------------------
449 tidySkolemTyVar :: TidyEnv -> TcTyVar -> (TidyEnv, TcTyVar)
450 -- Tidy the type inside a GenSkol, preparatory to printing it
451 tidySkolemTyVar env tv
452 = ASSERT( isSkolemTyVar tv || isSigTyVar tv )
453 (env1, mkTcTyVar (tyVarName tv) (tyVarKind tv) info1)
455 (env1, info1) = case tcTyVarDetails tv of
456 SkolemTv info -> (env1, SkolemTv info')
458 (env1, info') = tidy_skol_info env info
459 MetaTv (SigTv info) box -> (env1, MetaTv (SigTv info') box)
461 (env1, info') = tidy_skol_info env info
464 tidy_skol_info env (GenSkol tvs ty loc) = (env2, GenSkol tvs1 ty1 loc)
466 (env1, tvs1) = tidyOpenTyVars env tvs
467 (env2, ty1) = tidyOpenType env1 ty
468 tidy_skol_info env info = (env, info)
470 pprSkolTvBinding :: TcTyVar -> SDoc
471 -- Print info about the binding of a skolem tyvar,
472 -- or nothing if we don't have anything useful to say
474 = ppr_details (tcTyVarDetails tv)
476 ppr_details (MetaTv TauTv _) = quotes (ppr tv) <+> ptext SLIT("is a meta type variable")
477 ppr_details (MetaTv BoxTv _) = quotes (ppr tv) <+> ptext SLIT("is a boxy type variable")
478 ppr_details (MetaTv (SigTv info) _) = ppr_skol info
479 ppr_details (SkolemTv info) = ppr_skol info
481 ppr_skol UnkSkol = empty -- Unhelpful; omit
482 ppr_skol (SigSkol ctxt) = sep [quotes (ppr tv) <+> ptext SLIT("is bound by") <+> pprUserTypeCtxt ctxt,
483 nest 2 (ptext SLIT("at") <+> ppr (getSrcLoc tv))]
484 ppr_skol info = quotes (ppr tv) <+> pprSkolInfo info
486 pprSkolInfo :: SkolemInfo -> SDoc
487 pprSkolInfo (SigSkol ctxt) = ptext SLIT("is bound by") <+> pprUserTypeCtxt ctxt
488 pprSkolInfo (ClsSkol cls) = ptext SLIT("is bound by the class declaration for") <+> quotes (ppr cls)
489 pprSkolInfo (InstSkol df) = ptext SLIT("is bound by the instance declaration at") <+> ppr (getSrcLoc df)
490 pprSkolInfo (ArrowSkol loc) = ptext SLIT("is bound by the arrow form at") <+> ppr loc
491 pprSkolInfo (PatSkol dc loc) = sep [ptext SLIT("is bound by the pattern for") <+> quotes (ppr dc),
492 nest 2 (ptext SLIT("at") <+> ppr loc)]
493 pprSkolInfo (GenSkol tvs ty loc) = sep [sep [ptext SLIT("is bound by the polymorphic type"),
494 nest 2 (quotes (ppr (mkForAllTys tvs ty)))],
495 nest 2 (ptext SLIT("at") <+> ppr loc)]
497 -- For type variables the others are dealt with by pprSkolTvBinding.
498 -- For Insts, these cases should not happen
499 pprSkolInfo UnkSkol = panic "UnkSkol"
501 instance Outputable MetaDetails where
502 ppr Flexi = ptext SLIT("Flexi")
503 ppr (Indirect ty) = ptext SLIT("Indirect") <+> ppr ty
507 %************************************************************************
511 %************************************************************************
514 isImmutableTyVar, isSkolemTyVar, isExistentialTyVar, isBoxyTyVar, isMetaTyVar :: TyVar -> Bool
516 | isTcTyVar tv = isSkolemTyVar tv
520 = ASSERT( isTcTyVar tv )
521 case tcTyVarDetails tv of
525 isExistentialTyVar tv -- Existential type variable, bound by a pattern
526 = ASSERT( isTcTyVar tv )
527 case tcTyVarDetails tv of
528 SkolemTv (PatSkol _ _) -> True
532 = ASSERT2( isTcTyVar tv, ppr tv )
533 case tcTyVarDetails tv of
538 = ASSERT( isTcTyVar tv )
539 case tcTyVarDetails tv of
540 MetaTv BoxTv _ -> True
544 = ASSERT( isTcTyVar tv )
545 case tcTyVarDetails tv of
546 MetaTv (SigTv _) _ -> True
549 metaTvRef :: TyVar -> IORef MetaDetails
551 = ASSERT( isTcTyVar tv )
552 case tcTyVarDetails tv of
554 other -> pprPanic "metaTvRef" (ppr tv)
556 isFlexi, isIndirect :: MetaDetails -> Bool
558 isFlexi other = False
560 isIndirect (Indirect _) = True
561 isIndirect other = False
565 %************************************************************************
567 \subsection{Tau, sigma and rho}
569 %************************************************************************
572 mkSigmaTy :: [TyVar] -> [PredType] -> Type -> Type
573 mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkPhiTy theta tau)
575 mkPhiTy :: [PredType] -> Type -> Type
576 mkPhiTy theta ty = foldr (\p r -> FunTy (mkPredTy p) r) ty theta
579 @isTauTy@ tests for nested for-alls. It should not be called on a boxy type.
582 isTauTy :: Type -> Bool
583 isTauTy ty | Just ty' <- tcView ty = isTauTy ty'
584 isTauTy (TyVarTy tv) = ASSERT( not (isTcTyVar tv && isBoxyTyVar tv) )
586 isTauTy (TyConApp tc tys) = all isTauTy tys && isTauTyCon tc
587 isTauTy (AppTy a b) = isTauTy a && isTauTy b
588 isTauTy (FunTy a b) = isTauTy a && isTauTy b
589 isTauTy (PredTy p) = True -- Don't look through source types
590 isTauTy other = False
593 isTauTyCon :: TyCon -> Bool
594 -- Returns False for type synonyms whose expansion is a polytype
596 | isSynTyCon tc && not (isOpenTyCon tc) = isTauTy (snd (synTyConDefn tc))
600 isBoxyTy :: TcType -> Bool
601 isBoxyTy ty = any isBoxyTyVar (varSetElems (tcTyVarsOfType ty))
603 isRigidTy :: TcType -> Bool
604 -- A type is rigid if it has no meta type variables in it
605 isRigidTy ty = all isSkolemTyVar (varSetElems (tcTyVarsOfType ty))
607 isRefineableTy :: TcType -> Bool
608 -- A type should have type refinements applied to it if it has
609 -- free type variables, and they are all rigid
610 isRefineableTy ty = not (null tc_tvs) && all isSkolemTyVar tc_tvs
612 tc_tvs = varSetElems (tcTyVarsOfType ty)
615 getDFunTyKey :: Type -> OccName -- Get some string from a type, to be used to
616 -- construct a dictionary function name
617 getDFunTyKey ty | Just ty' <- tcView ty = getDFunTyKey ty'
618 getDFunTyKey (TyVarTy tv) = getOccName tv
619 getDFunTyKey (TyConApp tc _) = getOccName tc
620 getDFunTyKey (AppTy fun _) = getDFunTyKey fun
621 getDFunTyKey (FunTy arg _) = getOccName funTyCon
622 getDFunTyKey (ForAllTy _ t) = getDFunTyKey t
623 getDFunTyKey ty = pprPanic "getDFunTyKey" (pprType ty)
624 -- PredTy shouldn't happen
628 %************************************************************************
630 \subsection{Expanding and splitting}
632 %************************************************************************
634 These tcSplit functions are like their non-Tc analogues, but
635 a) they do not look through newtypes
636 b) they do not look through PredTys
637 c) [future] they ignore usage-type annotations
639 However, they are non-monadic and do not follow through mutable type
640 variables. It's up to you to make sure this doesn't matter.
643 tcSplitForAllTys :: Type -> ([TyVar], Type)
644 tcSplitForAllTys ty = split ty ty []
646 split orig_ty ty tvs | Just ty' <- tcView ty = split orig_ty ty' tvs
647 split orig_ty (ForAllTy tv ty) tvs
648 | not (isCoVar tv) = split ty ty (tv:tvs)
649 split orig_ty t tvs = (reverse tvs, orig_ty)
651 tcIsForAllTy ty | Just ty' <- tcView ty = tcIsForAllTy ty'
652 tcIsForAllTy (ForAllTy tv ty) = not (isCoVar tv)
653 tcIsForAllTy t = False
655 tcSplitPhiTy :: Type -> (ThetaType, Type)
656 tcSplitPhiTy ty = split ty ty []
658 split orig_ty ty tvs | Just ty' <- tcView ty = split orig_ty ty' tvs
660 split orig_ty (ForAllTy tv ty) ts
661 | isCoVar tv = split ty ty (eq_pred:ts)
663 PredTy eq_pred = tyVarKind tv
664 split orig_ty (FunTy arg res) ts
665 | Just p <- tcSplitPredTy_maybe arg = split res res (p:ts)
666 split orig_ty ty ts = (reverse ts, orig_ty)
668 tcSplitSigmaTy :: Type -> ([TyVar], ThetaType, Type)
669 tcSplitSigmaTy ty = case tcSplitForAllTys ty of
670 (tvs, rho) -> case tcSplitPhiTy rho of
671 (theta, tau) -> (tvs, theta, tau)
673 -----------------------
676 -> ( [([TyVar], ThetaType)], -- forall as.C => forall bs.D
677 TcSigmaType) -- The rest of the type
679 -- We need a loop here because we are now prepared to entertain
681 -- f:: forall a. Eq a => forall b. Baz b => tau
682 -- We want to instantiate this to
683 -- f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)}
685 tcMultiSplitSigmaTy sigma
686 = case (tcSplitSigmaTy sigma) of
687 ([],[],ty) -> ([], sigma)
688 (tvs, theta, ty) -> case tcMultiSplitSigmaTy ty of
689 (pairs, rest) -> ((tvs,theta):pairs, rest)
691 -----------------------
692 tcTyConAppTyCon :: Type -> TyCon
693 tcTyConAppTyCon ty = fst (tcSplitTyConApp ty)
695 tcTyConAppArgs :: Type -> [Type]
696 tcTyConAppArgs ty = snd (tcSplitTyConApp ty)
698 tcSplitTyConApp :: Type -> (TyCon, [Type])
699 tcSplitTyConApp ty = case tcSplitTyConApp_maybe ty of
701 Nothing -> pprPanic "tcSplitTyConApp" (pprType ty)
703 tcSplitTyConApp_maybe :: Type -> Maybe (TyCon, [Type])
704 tcSplitTyConApp_maybe ty | Just ty' <- tcView ty = tcSplitTyConApp_maybe ty'
705 tcSplitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
706 tcSplitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [arg,res])
707 -- Newtypes are opaque, so they may be split
708 -- However, predicates are not treated
709 -- as tycon applications by the type checker
710 tcSplitTyConApp_maybe other = Nothing
712 -----------------------
713 tcSplitFunTys :: Type -> ([Type], Type)
714 tcSplitFunTys ty = case tcSplitFunTy_maybe ty of
716 Just (arg,res) -> (arg:args, res')
718 (args,res') = tcSplitFunTys res
720 tcSplitFunTy_maybe :: Type -> Maybe (Type, Type)
721 tcSplitFunTy_maybe ty | Just ty' <- tcView ty = tcSplitFunTy_maybe ty'
722 tcSplitFunTy_maybe (FunTy arg res) = Just (arg, res)
723 tcSplitFunTy_maybe other = Nothing
727 -> Arity -- N: Number of desired args
728 -> ([TcSigmaType], -- Arg types (N or fewer)
729 TcSigmaType) -- The rest of the type
731 tcSplitFunTysN ty n_args
734 | Just (arg,res) <- tcSplitFunTy_maybe ty
735 = case tcSplitFunTysN res (n_args - 1) of
736 (args, res) -> (arg:args, res)
740 tcSplitFunTy ty = expectJust "tcSplitFunTy" (tcSplitFunTy_maybe ty)
741 tcFunArgTy ty = fst (tcSplitFunTy ty)
742 tcFunResultTy ty = snd (tcSplitFunTy ty)
744 -----------------------
745 tcSplitAppTy_maybe :: Type -> Maybe (Type, Type)
746 tcSplitAppTy_maybe ty | Just ty' <- tcView ty = tcSplitAppTy_maybe ty'
747 tcSplitAppTy_maybe ty = repSplitAppTy_maybe ty
749 tcSplitAppTy :: Type -> (Type, Type)
750 tcSplitAppTy ty = case tcSplitAppTy_maybe ty of
752 Nothing -> pprPanic "tcSplitAppTy" (pprType ty)
754 tcSplitAppTys :: Type -> (Type, [Type])
758 go ty args = case tcSplitAppTy_maybe ty of
759 Just (ty', arg) -> go ty' (arg:args)
762 -----------------------
763 tcGetTyVar_maybe :: Type -> Maybe TyVar
764 tcGetTyVar_maybe ty | Just ty' <- tcView ty = tcGetTyVar_maybe ty'
765 tcGetTyVar_maybe (TyVarTy tv) = Just tv
766 tcGetTyVar_maybe other = Nothing
768 tcGetTyVar :: String -> Type -> TyVar
769 tcGetTyVar msg ty = expectJust msg (tcGetTyVar_maybe ty)
771 tcIsTyVarTy :: Type -> Bool
772 tcIsTyVarTy ty = maybeToBool (tcGetTyVar_maybe ty)
774 -----------------------
775 tcSplitDFunTy :: Type -> ([TyVar], [PredType], Class, [Type])
776 -- Split the type of a dictionary function
778 = case tcSplitSigmaTy ty of { (tvs, theta, tau) ->
779 case tcSplitDFunHead tau of { (clas, tys) ->
780 (tvs, theta, clas, tys) }}
782 tcSplitDFunHead :: Type -> (Class, [Type])
784 = case tcSplitPredTy_maybe tau of
785 Just (ClassP clas tys) -> (clas, tys)
786 other -> panic "tcSplitDFunHead"
788 tcValidInstHeadTy :: Type -> Bool
789 -- Used in Haskell-98 mode, for the argument types of an instance head
790 -- These must not be type synonyms, but everywhere else type synonyms
791 -- are transparent, so we need a special function here
794 NoteTy _ ty -> tcValidInstHeadTy ty
795 TyConApp tc tys -> not (isSynTyCon tc) && ok tys
796 FunTy arg res -> ok [arg, res]
799 -- Check that all the types are type variables,
800 -- and that each is distinct
801 ok tys = equalLength tvs tys && hasNoDups tvs
803 tvs = mapCatMaybes get_tv tys
805 get_tv (NoteTy _ ty) = get_tv ty -- Again, do not look
806 get_tv (TyVarTy tv) = Just tv -- through synonyms
807 get_tv other = Nothing
812 %************************************************************************
814 \subsection{Predicate types}
816 %************************************************************************
819 tcSplitPredTy_maybe :: Type -> Maybe PredType
820 -- Returns Just for predicates only
821 tcSplitPredTy_maybe ty | Just ty' <- tcView ty = tcSplitPredTy_maybe ty'
822 tcSplitPredTy_maybe (PredTy p) = Just p
823 tcSplitPredTy_maybe other = Nothing
825 predTyUnique :: PredType -> Unique
826 predTyUnique (IParam n _) = getUnique (ipNameName n)
827 predTyUnique (ClassP clas tys) = getUnique clas
829 mkPredName :: Unique -> SrcLoc -> PredType -> Name
830 mkPredName uniq loc (ClassP cls tys) = mkInternalName uniq (mkDictOcc (getOccName cls)) loc
831 mkPredName uniq loc (IParam ip ty) = mkInternalName uniq (getOccName (ipNameName ip)) loc
835 --------------------- Dictionary types ---------------------------------
838 mkClassPred clas tys = ClassP clas tys
840 isClassPred :: PredType -> Bool
841 isClassPred (ClassP clas tys) = True
842 isClassPred other = False
844 isTyVarClassPred (ClassP clas tys) = all tcIsTyVarTy tys
845 isTyVarClassPred other = False
847 getClassPredTys_maybe :: PredType -> Maybe (Class, [Type])
848 getClassPredTys_maybe (ClassP clas tys) = Just (clas, tys)
849 getClassPredTys_maybe _ = Nothing
851 getClassPredTys :: PredType -> (Class, [Type])
852 getClassPredTys (ClassP clas tys) = (clas, tys)
853 getClassPredTys other = panic "getClassPredTys"
855 isEqPred :: PredType -> Bool
856 isEqPred (EqPred {}) = True
859 mkDictTy :: Class -> [Type] -> Type
860 mkDictTy clas tys = mkPredTy (ClassP clas tys)
862 isDictTy :: Type -> Bool
863 isDictTy ty | Just ty' <- tcView ty = isDictTy ty'
864 isDictTy (PredTy p) = isClassPred p
865 isDictTy other = False
868 --------------------- Implicit parameters ---------------------------------
871 isIPPred :: PredType -> Bool
872 isIPPred (IParam _ _) = True
873 isIPPred other = False
875 isInheritablePred :: PredType -> Bool
876 -- Can be inherited by a context. For example, consider
877 -- f x = let g y = (?v, y+x)
878 -- in (g 3 with ?v = 8,
880 -- The point is that g's type must be quantifed over ?v:
881 -- g :: (?v :: a) => a -> a
882 -- but it doesn't need to be quantified over the Num a dictionary
883 -- which can be free in g's rhs, and shared by both calls to g
884 isInheritablePred (ClassP _ _) = True
885 isInheritablePred other = False
887 isLinearPred :: TcPredType -> Bool
888 isLinearPred (IParam (Linear n) _) = True
889 isLinearPred other = False
892 --------------------- Equality predicates ---------------------------------
894 substEqSpec :: TvSubst -> [(TyVar,Type)] -> [(TcType,TcType)]
895 substEqSpec subst eq_spec = [ (substTyVar subst tv, substTy subst ty)
896 | (tv,ty) <- eq_spec]
899 --------------------- The stupid theta (sigh) ---------------------------------
902 dataConsStupidTheta :: [DataCon] -> ThetaType
903 -- Union the stupid thetas from all the specified constructors (non-empty)
904 -- All the constructors should have the same result type, modulo alpha conversion
905 -- The resulting ThetaType uses type variables from the *first* constructor in the list
907 -- It's here because it's used in MkId.mkRecordSelId, and in TcExpr
908 dataConsStupidTheta (con1:cons)
909 = nubBy tcEqPred all_preds
911 all_preds = dataConStupidTheta con1 ++ other_stupids
912 res_tys1 = dataConResTys con1
913 tvs1 = tyVarsOfTypes res_tys1
914 other_stupids = [ substPred subst pred
916 , let Just subst = tcMatchTys tvs1 res_tys1 (dataConResTys con)
917 , pred <- dataConStupidTheta con ]
918 dataConsStupidTheta [] = panic "dataConsStupidTheta"
922 %************************************************************************
924 \subsection{Predicates}
926 %************************************************************************
928 isSigmaTy returns true of any qualified type. It doesn't *necessarily* have
930 f :: (?x::Int) => Int -> Int
933 isSigmaTy :: Type -> Bool
934 isSigmaTy ty | Just ty' <- tcView ty = isSigmaTy ty'
935 isSigmaTy (ForAllTy tyvar ty) = True
936 isSigmaTy (FunTy a b) = isPredTy a
939 isOverloadedTy :: Type -> Bool
940 isOverloadedTy ty | Just ty' <- tcView ty = isOverloadedTy ty'
941 isOverloadedTy (ForAllTy tyvar ty) = isOverloadedTy ty
942 isOverloadedTy (FunTy a b) = isPredTy a
943 isOverloadedTy _ = False
945 isPredTy :: Type -> Bool -- Belongs in TcType because it does
946 -- not look through newtypes, or predtypes (of course)
947 isPredTy ty | Just ty' <- tcView ty = isPredTy ty'
948 isPredTy (PredTy sty) = True
953 isFloatTy = is_tc floatTyConKey
954 isDoubleTy = is_tc doubleTyConKey
955 isIntegerTy = is_tc integerTyConKey
956 isIntTy = is_tc intTyConKey
957 isBoolTy = is_tc boolTyConKey
958 isUnitTy = is_tc unitTyConKey
960 is_tc :: Unique -> Type -> Bool
961 -- Newtypes are opaque to this
962 is_tc uniq ty = case tcSplitTyConApp_maybe ty of
963 Just (tc, _) -> uniq == getUnique tc
968 %************************************************************************
972 %************************************************************************
975 deNoteType :: Type -> Type
976 -- Remove all *outermost* type synonyms and other notes
977 deNoteType ty | Just ty' <- tcView ty = deNoteType ty'
982 tcTyVarsOfType :: Type -> TcTyVarSet
983 -- Just the *TcTyVars* free in the type
984 -- (Types.tyVarsOfTypes finds all free TyVars)
985 tcTyVarsOfType (TyVarTy tv) = if isTcTyVar tv then unitVarSet tv
987 tcTyVarsOfType (TyConApp tycon tys) = tcTyVarsOfTypes tys
988 tcTyVarsOfType (NoteTy _ ty) = tcTyVarsOfType ty
989 tcTyVarsOfType (PredTy sty) = tcTyVarsOfPred sty
990 tcTyVarsOfType (FunTy arg res) = tcTyVarsOfType arg `unionVarSet` tcTyVarsOfType res
991 tcTyVarsOfType (AppTy fun arg) = tcTyVarsOfType fun `unionVarSet` tcTyVarsOfType arg
992 tcTyVarsOfType (ForAllTy tyvar ty) = (tcTyVarsOfType ty `delVarSet` tyvar)
993 `unionVarSet` tcTyVarsOfTyVar tyvar
994 -- We do sometimes quantify over skolem TcTyVars
996 tcTyVarsOfTyVar :: TcTyVar -> TyVarSet
997 tcTyVarsOfTyVar tv | isCoVar tv = tcTyVarsOfType (tyVarKind tv)
998 | otherwise = emptyVarSet
1000 tcTyVarsOfTypes :: [Type] -> TyVarSet
1001 tcTyVarsOfTypes tys = foldr (unionVarSet.tcTyVarsOfType) emptyVarSet tys
1003 tcTyVarsOfPred :: PredType -> TyVarSet
1004 tcTyVarsOfPred (IParam _ ty) = tcTyVarsOfType ty
1005 tcTyVarsOfPred (ClassP _ tys) = tcTyVarsOfTypes tys
1006 tcTyVarsOfPred (EqPred ty1 ty2) = tcTyVarsOfType ty1 `unionVarSet` tcTyVarsOfType ty2
1009 Note [Silly type synonym]
1010 ~~~~~~~~~~~~~~~~~~~~~~~~~
1013 What are the free tyvars of (T x)? Empty, of course!
1014 Here's the example that Ralf Laemmel showed me:
1015 foo :: (forall a. C u a -> C u a) -> u
1016 mappend :: Monoid u => u -> u -> u
1018 bar :: Monoid u => u
1019 bar = foo (\t -> t `mappend` t)
1020 We have to generalise at the arg to f, and we don't
1021 want to capture the constraint (Monad (C u a)) because
1022 it appears to mention a. Pretty silly, but it was useful to him.
1024 exactTyVarsOfType is used by the type checker to figure out exactly
1025 which type variables are mentioned in a type. It's also used in the
1026 smart-app checking code --- see TcExpr.tcIdApp
1029 exactTyVarsOfType :: TcType -> TyVarSet
1030 -- Find the free type variables (of any kind)
1031 -- but *expand* type synonyms. See Note [Silly type synonym] above.
1032 exactTyVarsOfType ty
1035 go ty | Just ty' <- tcView ty = go ty' -- This is the key line
1036 go (TyVarTy tv) = unitVarSet tv
1037 go (TyConApp tycon tys) = exactTyVarsOfTypes tys
1038 go (PredTy ty) = go_pred ty
1039 go (FunTy arg res) = go arg `unionVarSet` go res
1040 go (AppTy fun arg) = go fun `unionVarSet` go arg
1041 go (ForAllTy tyvar ty) = delVarSet (go ty) tyvar
1042 `unionVarSet` go_tv tyvar
1044 go_pred (IParam _ ty) = go ty
1045 go_pred (ClassP _ tys) = exactTyVarsOfTypes tys
1046 go_pred (EqPred ty1 ty2) = go ty1 `unionVarSet` go ty2
1048 go_tv tyvar | isCoVar tyvar = go (tyVarKind tyvar)
1049 | otherwise = emptyVarSet
1051 exactTyVarsOfTypes :: [TcType] -> TyVarSet
1052 exactTyVarsOfTypes tys = foldr (unionVarSet . exactTyVarsOfType) emptyVarSet tys
1055 Find the free tycons and classes of a type. This is used in the front
1056 end of the compiler.
1059 tyClsNamesOfType :: Type -> NameSet
1060 tyClsNamesOfType (TyVarTy tv) = emptyNameSet
1061 tyClsNamesOfType (TyConApp tycon tys) = unitNameSet (getName tycon) `unionNameSets` tyClsNamesOfTypes tys
1062 tyClsNamesOfType (NoteTy _ ty2) = tyClsNamesOfType ty2
1063 tyClsNamesOfType (PredTy (IParam n ty)) = tyClsNamesOfType ty
1064 tyClsNamesOfType (PredTy (ClassP cl tys)) = unitNameSet (getName cl) `unionNameSets` tyClsNamesOfTypes tys
1065 tyClsNamesOfType (PredTy (EqPred ty1 ty2)) = tyClsNamesOfType ty1 `unionNameSets` tyClsNamesOfType ty2
1066 tyClsNamesOfType (FunTy arg res) = tyClsNamesOfType arg `unionNameSets` tyClsNamesOfType res
1067 tyClsNamesOfType (AppTy fun arg) = tyClsNamesOfType fun `unionNameSets` tyClsNamesOfType arg
1068 tyClsNamesOfType (ForAllTy tyvar ty) = tyClsNamesOfType ty
1070 tyClsNamesOfTypes tys = foldr (unionNameSets . tyClsNamesOfType) emptyNameSet tys
1072 tyClsNamesOfDFunHead :: Type -> NameSet
1073 -- Find the free type constructors and classes
1074 -- of the head of the dfun instance type
1075 -- The 'dfun_head_type' is because of
1076 -- instance Foo a => Baz T where ...
1077 -- The decl is an orphan if Baz and T are both not locally defined,
1078 -- even if Foo *is* locally defined
1079 tyClsNamesOfDFunHead dfun_ty
1080 = case tcSplitSigmaTy dfun_ty of
1081 (tvs,_,head_ty) -> tyClsNamesOfType head_ty
1083 classesOfTheta :: ThetaType -> [Class]
1084 -- Looks just for ClassP things; maybe it should check
1085 classesOfTheta preds = [ c | ClassP c _ <- preds ]
1089 %************************************************************************
1091 \subsection[TysWiredIn-ext-type]{External types}
1093 %************************************************************************
1095 The compiler's foreign function interface supports the passing of a
1096 restricted set of types as arguments and results (the restricting factor
1100 tcSplitIOType_maybe :: Type -> Maybe (TyCon, Type)
1101 -- (isIOType t) returns (Just (IO,t')) if t is of the form (IO t'), or
1102 -- some newtype wrapping thereof
1103 -- returns Nothing otherwise
1104 tcSplitIOType_maybe ty
1105 | Just (io_tycon, [io_res_ty]) <- tcSplitTyConApp_maybe ty,
1106 -- This split absolutely has to be a tcSplit, because we must
1107 -- see the IO type; and it's a newtype which is transparent to splitTyConApp.
1108 io_tycon `hasKey` ioTyConKey
1109 = Just (io_tycon, io_res_ty)
1111 | Just ty' <- coreView ty -- Look through non-recursive newtypes
1112 = tcSplitIOType_maybe ty'
1117 isFFITy :: Type -> Bool
1118 -- True for any TyCon that can possibly be an arg or result of an FFI call
1119 isFFITy ty = checkRepTyCon legalFFITyCon ty
1121 isFFIArgumentTy :: DynFlags -> Safety -> Type -> Bool
1122 -- Checks for valid argument type for a 'foreign import'
1123 isFFIArgumentTy dflags safety ty
1124 = checkRepTyCon (legalOutgoingTyCon dflags safety) ty
1126 isFFIExternalTy :: Type -> Bool
1127 -- Types that are allowed as arguments of a 'foreign export'
1128 isFFIExternalTy ty = checkRepTyCon legalFEArgTyCon ty
1130 isFFIImportResultTy :: DynFlags -> Type -> Bool
1131 isFFIImportResultTy dflags ty
1132 = checkRepTyCon (legalFIResultTyCon dflags) ty
1134 isFFIExportResultTy :: Type -> Bool
1135 isFFIExportResultTy ty = checkRepTyCon legalFEResultTyCon ty
1137 isFFIDynArgumentTy :: Type -> Bool
1138 -- The argument type of a foreign import dynamic must be Ptr, FunPtr, Addr,
1139 -- or a newtype of either.
1140 isFFIDynArgumentTy = checkRepTyConKey [ptrTyConKey, funPtrTyConKey]
1142 isFFIDynResultTy :: Type -> Bool
1143 -- The result type of a foreign export dynamic must be Ptr, FunPtr, Addr,
1144 -- or a newtype of either.
1145 isFFIDynResultTy = checkRepTyConKey [ptrTyConKey, funPtrTyConKey]
1147 isFFILabelTy :: Type -> Bool
1148 -- The type of a foreign label must be Ptr, FunPtr, Addr,
1149 -- or a newtype of either.
1150 isFFILabelTy = checkRepTyConKey [ptrTyConKey, funPtrTyConKey]
1152 isFFIDotnetTy :: DynFlags -> Type -> Bool
1153 isFFIDotnetTy dflags ty
1154 = checkRepTyCon (\ tc -> (legalFIResultTyCon dflags tc ||
1155 isFFIDotnetObjTy ty || isStringTy ty)) ty
1157 -- Support String as an argument or result from a .NET FFI call.
1159 case tcSplitTyConApp_maybe (repType ty) of
1161 | tc == listTyCon ->
1162 case tcSplitTyConApp_maybe (repType arg_ty) of
1163 Just (cc,[]) -> cc == charTyCon
1167 -- Support String as an argument or result from a .NET FFI call.
1168 isFFIDotnetObjTy ty =
1170 (_, t_ty) = tcSplitForAllTys ty
1172 case tcSplitTyConApp_maybe (repType t_ty) of
1173 Just (tc, [arg_ty]) | getName tc == objectTyConName -> True
1176 toDNType :: Type -> DNType
1178 | isStringTy ty = DNString
1179 | isFFIDotnetObjTy ty = DNObject
1180 | Just (tc,argTys) <- tcSplitTyConApp_maybe ty
1181 = case lookup (getUnique tc) dn_assoc of
1184 | tc `hasKey` ioTyConKey -> toDNType (head argTys)
1185 | otherwise -> pprPanic ("toDNType: unsupported .NET type")
1186 (pprType ty <+> parens (hcat (map pprType argTys)) <+> ppr tc)
1187 | otherwise = panic "toDNType" -- Is this right?
1189 dn_assoc :: [ (Unique, DNType) ]
1190 dn_assoc = [ (unitTyConKey, DNUnit)
1191 , (intTyConKey, DNInt)
1192 , (int8TyConKey, DNInt8)
1193 , (int16TyConKey, DNInt16)
1194 , (int32TyConKey, DNInt32)
1195 , (int64TyConKey, DNInt64)
1196 , (wordTyConKey, DNInt)
1197 , (word8TyConKey, DNWord8)
1198 , (word16TyConKey, DNWord16)
1199 , (word32TyConKey, DNWord32)
1200 , (word64TyConKey, DNWord64)
1201 , (floatTyConKey, DNFloat)
1202 , (doubleTyConKey, DNDouble)
1203 , (ptrTyConKey, DNPtr)
1204 , (funPtrTyConKey, DNPtr)
1205 , (charTyConKey, DNChar)
1206 , (boolTyConKey, DNBool)
1209 checkRepTyCon :: (TyCon -> Bool) -> Type -> Bool
1210 -- Look through newtypes
1211 -- Non-recursive ones are transparent to splitTyConApp,
1212 -- but recursive ones aren't. Manuel had:
1213 -- newtype T = MkT (Ptr T)
1214 -- and wanted it to work...
1215 checkRepTyCon check_tc ty
1216 | Just (tc,_) <- splitTyConApp_maybe (repType ty) = check_tc tc
1219 checkRepTyConKey :: [Unique] -> Type -> Bool
1220 -- Like checkRepTyCon, but just looks at the TyCon key
1221 checkRepTyConKey keys
1222 = checkRepTyCon (\tc -> tyConUnique tc `elem` keys)
1225 ----------------------------------------------
1226 These chaps do the work; they are not exported
1227 ----------------------------------------------
1230 legalFEArgTyCon :: TyCon -> Bool
1232 -- It's illegal to make foreign exports that take unboxed
1233 -- arguments. The RTS API currently can't invoke such things. --SDM 7/2000
1234 = boxedMarshalableTyCon tc
1236 legalFIResultTyCon :: DynFlags -> TyCon -> Bool
1237 legalFIResultTyCon dflags tc
1238 | tc == unitTyCon = True
1239 | otherwise = marshalableTyCon dflags tc
1241 legalFEResultTyCon :: TyCon -> Bool
1242 legalFEResultTyCon tc
1243 | tc == unitTyCon = True
1244 | otherwise = boxedMarshalableTyCon tc
1246 legalOutgoingTyCon :: DynFlags -> Safety -> TyCon -> Bool
1247 -- Checks validity of types going from Haskell -> external world
1248 legalOutgoingTyCon dflags safety tc
1249 = marshalableTyCon dflags tc
1251 legalFFITyCon :: TyCon -> Bool
1252 -- True for any TyCon that can possibly be an arg or result of an FFI call
1254 = isUnLiftedTyCon tc || boxedMarshalableTyCon tc || tc == unitTyCon
1256 marshalableTyCon dflags tc
1257 = (dopt Opt_GlasgowExts dflags && isUnLiftedTyCon tc)
1258 || boxedMarshalableTyCon tc
1260 boxedMarshalableTyCon tc
1261 = getUnique tc `elem` [ intTyConKey, int8TyConKey, int16TyConKey
1262 , int32TyConKey, int64TyConKey
1263 , wordTyConKey, word8TyConKey, word16TyConKey
1264 , word32TyConKey, word64TyConKey
1265 , floatTyConKey, doubleTyConKey
1266 , ptrTyConKey, funPtrTyConKey