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, unboxedTypeKind, 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,
138 -- ??? unboxedTypeKind,
140 liftedTypeKind, openTypeKind, mkArrowKind,
141 tySuperKind, isLiftedTypeKind,
142 mkArrowKinds, mkForAllTy, mkForAllTys,
143 defaultKind, isSubArgTypeKind, isSubOpenTypeKind,
144 mkFunTy, mkFunTys, zipFunTys,
146 mkAppTys, applyTy, applyTys,
147 mkTyVarTy, mkTyVarTys, mkTyConTy, mkPredTy,
148 mkPredTys, isUnLiftedType,
149 isUnboxedTupleType, isPrimitiveType,
151 tidyTopType, tidyType, tidyPred, tidyTypes,
152 tidyFreeTyVars, tidyOpenType, tidyOpenTypes,
153 tidyTyVarBndr, tidyOpenTyVar,
154 tidyOpenTyVars, tidyKind,
157 tcEqType, tcEqTypes, tcCmpType, tcCmpTypes,
158 tcEqPred, tcCmpPred, tcEqTypeX, eqKind,
161 TvSubstEnv, emptyTvSubst, mkTvSubst, zipTyEnv,
162 mkOpenTvSubst, zipOpenTvSubst, zipTopTvSubst, mkTopTvSubst,
163 getTvSubstEnv, setTvSubstEnv, getTvInScope, extendTvInScope,
164 extendTvSubst, extendTvSubstList, isInScope, notElemTvSubst,
165 substTy, substTys, substTyWith, substTheta,
166 substTyVar, substTyVarBndr, substPred, lookupTyVar,
168 typeKind, repType, coreView, repSplitAppTy_maybe,
169 pprKind, pprParendKind,
170 pprType, pprParendType, pprTyThingCategory,
171 pprPred, pprTheta, pprThetaArrow, pprClassPred
173 import TyCon ( TyCon, isUnLiftedTyCon, isSynTyCon, synTyConDefn, tyConUnique )
174 import DataCon ( DataCon, dataConStupidTheta, dataConResTys )
175 import Class ( Class )
176 import Var ( TyVar, Id, 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 ( snocView, 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
595 isTauTyCon tc | isSynTyCon tc = isTauTy (snd (synTyConDefn tc))
599 isBoxyTy :: TcType -> Bool
600 isBoxyTy ty = any isBoxyTyVar (varSetElems (tcTyVarsOfType ty))
602 isRigidTy :: TcType -> Bool
603 -- A type is rigid if it has no meta type variables in it
604 isRigidTy ty = all isSkolemTyVar (varSetElems (tcTyVarsOfType ty))
606 isRefineableTy :: TcType -> Bool
607 -- A type should have type refinements applied to it if it has
608 -- free type variables, and they are all rigid
609 isRefineableTy ty = not (null tc_tvs) && all isSkolemTyVar tc_tvs
611 tc_tvs = varSetElems (tcTyVarsOfType ty)
614 getDFunTyKey :: Type -> OccName -- Get some string from a type, to be used to
615 -- construct a dictionary function name
616 getDFunTyKey ty | Just ty' <- tcView ty = getDFunTyKey ty'
617 getDFunTyKey (TyVarTy tv) = getOccName tv
618 getDFunTyKey (TyConApp tc _) = getOccName tc
619 getDFunTyKey (AppTy fun _) = getDFunTyKey fun
620 getDFunTyKey (FunTy arg _) = getOccName funTyCon
621 getDFunTyKey (ForAllTy _ t) = getDFunTyKey t
622 getDFunTyKey ty = pprPanic "getDFunTyKey" (pprType ty)
623 -- PredTy shouldn't happen
627 %************************************************************************
629 \subsection{Expanding and splitting}
631 %************************************************************************
633 These tcSplit functions are like their non-Tc analogues, but
634 a) they do not look through newtypes
635 b) they do not look through PredTys
636 c) [future] they ignore usage-type annotations
638 However, they are non-monadic and do not follow through mutable type
639 variables. It's up to you to make sure this doesn't matter.
642 tcSplitForAllTys :: Type -> ([TyVar], Type)
643 tcSplitForAllTys ty = split ty ty []
645 split orig_ty ty tvs | Just ty' <- tcView ty = split orig_ty ty' tvs
646 split orig_ty (ForAllTy tv ty) tvs = split ty ty (tv:tvs)
647 split orig_ty t tvs = (reverse tvs, orig_ty)
649 tcIsForAllTy ty | Just ty' <- tcView ty = tcIsForAllTy ty'
650 tcIsForAllTy (ForAllTy tv ty) = True
651 tcIsForAllTy t = False
653 tcSplitPhiTy :: Type -> (ThetaType, Type)
654 tcSplitPhiTy ty = split ty ty []
656 split orig_ty ty tvs | Just ty' <- tcView ty = split orig_ty ty' tvs
657 split orig_ty (FunTy arg res) ts
658 | Just p <- tcSplitPredTy_maybe arg = split res res (p:ts)
659 split orig_ty ty ts = (reverse ts, orig_ty)
661 tcSplitSigmaTy :: Type -> ([TyVar], ThetaType, Type)
662 tcSplitSigmaTy ty = case tcSplitForAllTys ty of
663 (tvs, rho) -> case tcSplitPhiTy rho of
664 (theta, tau) -> (tvs, theta, tau)
666 -----------------------
669 -> ( [([TyVar], ThetaType)], -- forall as.C => forall bs.D
670 TcSigmaType) -- The rest of the type
672 -- We need a loop here because we are now prepared to entertain
674 -- f:: forall a. Eq a => forall b. Baz b => tau
675 -- We want to instantiate this to
676 -- f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)}
678 tcMultiSplitSigmaTy sigma
679 = case (tcSplitSigmaTy sigma) of
680 ([],[],ty) -> ([], sigma)
681 (tvs, theta, ty) -> case tcMultiSplitSigmaTy ty of
682 (pairs, rest) -> ((tvs,theta):pairs, rest)
684 -----------------------
685 tcTyConAppTyCon :: Type -> TyCon
686 tcTyConAppTyCon ty = fst (tcSplitTyConApp ty)
688 tcTyConAppArgs :: Type -> [Type]
689 tcTyConAppArgs ty = snd (tcSplitTyConApp ty)
691 tcSplitTyConApp :: Type -> (TyCon, [Type])
692 tcSplitTyConApp ty = case tcSplitTyConApp_maybe ty of
694 Nothing -> pprPanic "tcSplitTyConApp" (pprType ty)
696 tcSplitTyConApp_maybe :: Type -> Maybe (TyCon, [Type])
697 tcSplitTyConApp_maybe ty | Just ty' <- tcView ty = tcSplitTyConApp_maybe ty'
698 tcSplitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
699 tcSplitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [arg,res])
700 -- Newtypes are opaque, so they may be split
701 -- However, predicates are not treated
702 -- as tycon applications by the type checker
703 tcSplitTyConApp_maybe other = Nothing
705 -----------------------
706 tcSplitFunTys :: Type -> ([Type], Type)
707 tcSplitFunTys ty = case tcSplitFunTy_maybe ty of
709 Just (arg,res) -> (arg:args, res')
711 (args,res') = tcSplitFunTys res
713 tcSplitFunTy_maybe :: Type -> Maybe (Type, Type)
714 tcSplitFunTy_maybe ty | Just ty' <- tcView ty = tcSplitFunTy_maybe ty'
715 tcSplitFunTy_maybe (FunTy arg res) = Just (arg, res)
716 tcSplitFunTy_maybe other = Nothing
720 -> Arity -- N: Number of desired args
721 -> ([TcSigmaType], -- Arg types (N or fewer)
722 TcSigmaType) -- The rest of the type
724 tcSplitFunTysN ty n_args
727 | Just (arg,res) <- tcSplitFunTy_maybe ty
728 = case tcSplitFunTysN res (n_args - 1) of
729 (args, res) -> (arg:args, res)
733 tcSplitFunTy ty = expectJust "tcSplitFunTy" (tcSplitFunTy_maybe ty)
734 tcFunArgTy ty = fst (tcSplitFunTy ty)
735 tcFunResultTy ty = snd (tcSplitFunTy ty)
737 -----------------------
738 tcSplitAppTy_maybe :: Type -> Maybe (Type, Type)
739 tcSplitAppTy_maybe ty | Just ty' <- tcView ty = tcSplitAppTy_maybe ty'
740 tcSplitAppTy_maybe ty = repSplitAppTy_maybe ty
742 tcSplitAppTy :: Type -> (Type, Type)
743 tcSplitAppTy ty = case tcSplitAppTy_maybe ty of
745 Nothing -> pprPanic "tcSplitAppTy" (pprType ty)
747 tcSplitAppTys :: Type -> (Type, [Type])
751 go ty args = case tcSplitAppTy_maybe ty of
752 Just (ty', arg) -> go ty' (arg:args)
755 -----------------------
756 tcGetTyVar_maybe :: Type -> Maybe TyVar
757 tcGetTyVar_maybe ty | Just ty' <- tcView ty = tcGetTyVar_maybe ty'
758 tcGetTyVar_maybe (TyVarTy tv) = Just tv
759 tcGetTyVar_maybe other = Nothing
761 tcGetTyVar :: String -> Type -> TyVar
762 tcGetTyVar msg ty = expectJust msg (tcGetTyVar_maybe ty)
764 tcIsTyVarTy :: Type -> Bool
765 tcIsTyVarTy ty = maybeToBool (tcGetTyVar_maybe ty)
767 -----------------------
768 tcSplitDFunTy :: Type -> ([TyVar], [PredType], Class, [Type])
769 -- Split the type of a dictionary function
771 = case tcSplitSigmaTy ty of { (tvs, theta, tau) ->
772 case tcSplitDFunHead tau of { (clas, tys) ->
773 (tvs, theta, clas, tys) }}
775 tcSplitDFunHead :: Type -> (Class, [Type])
777 = case tcSplitPredTy_maybe tau of
778 Just (ClassP clas tys) -> (clas, tys)
779 other -> panic "tcSplitDFunHead"
781 tcValidInstHeadTy :: Type -> Bool
782 -- Used in Haskell-98 mode, for the argument types of an instance head
783 -- These must not be type synonyms, but everywhere else type synonyms
784 -- are transparent, so we need a special function here
787 NoteTy _ ty -> tcValidInstHeadTy ty
788 TyConApp tc tys -> not (isSynTyCon tc) && ok tys
789 FunTy arg res -> ok [arg, res]
792 -- Check that all the types are type variables,
793 -- and that each is distinct
794 ok tys = equalLength tvs tys && hasNoDups tvs
796 tvs = mapCatMaybes get_tv tys
798 get_tv (NoteTy _ ty) = get_tv ty -- Again, do not look
799 get_tv (TyVarTy tv) = Just tv -- through synonyms
800 get_tv other = Nothing
805 %************************************************************************
807 \subsection{Predicate types}
809 %************************************************************************
812 tcSplitPredTy_maybe :: Type -> Maybe PredType
813 -- Returns Just for predicates only
814 tcSplitPredTy_maybe ty | Just ty' <- tcView ty = tcSplitPredTy_maybe ty'
815 tcSplitPredTy_maybe (PredTy p) = Just p
816 tcSplitPredTy_maybe other = Nothing
818 predTyUnique :: PredType -> Unique
819 predTyUnique (IParam n _) = getUnique (ipNameName n)
820 predTyUnique (ClassP clas tys) = getUnique clas
822 mkPredName :: Unique -> SrcLoc -> PredType -> Name
823 mkPredName uniq loc (ClassP cls tys) = mkInternalName uniq (mkDictOcc (getOccName cls)) loc
824 mkPredName uniq loc (IParam ip ty) = mkInternalName uniq (getOccName (ipNameName ip)) loc
828 --------------------- Dictionary types ---------------------------------
831 mkClassPred clas tys = ClassP clas tys
833 isClassPred :: PredType -> Bool
834 isClassPred (ClassP clas tys) = True
835 isClassPred other = False
837 isTyVarClassPred (ClassP clas tys) = all tcIsTyVarTy tys
838 isTyVarClassPred other = False
840 getClassPredTys_maybe :: PredType -> Maybe (Class, [Type])
841 getClassPredTys_maybe (ClassP clas tys) = Just (clas, tys)
842 getClassPredTys_maybe _ = Nothing
844 getClassPredTys :: PredType -> (Class, [Type])
845 getClassPredTys (ClassP clas tys) = (clas, tys)
846 getClassPredTys other = panic "getClassPredTys"
848 isEqPred :: PredType -> Bool
849 isEqPred (EqPred {}) = True
852 mkDictTy :: Class -> [Type] -> Type
853 mkDictTy clas tys = mkPredTy (ClassP clas tys)
855 isDictTy :: Type -> Bool
856 isDictTy ty | Just ty' <- tcView ty = isDictTy ty'
857 isDictTy (PredTy p) = isClassPred p
858 isDictTy other = False
861 --------------------- Implicit parameters ---------------------------------
864 isIPPred :: PredType -> Bool
865 isIPPred (IParam _ _) = True
866 isIPPred other = False
868 isInheritablePred :: PredType -> Bool
869 -- Can be inherited by a context. For example, consider
870 -- f x = let g y = (?v, y+x)
871 -- in (g 3 with ?v = 8,
873 -- The point is that g's type must be quantifed over ?v:
874 -- g :: (?v :: a) => a -> a
875 -- but it doesn't need to be quantified over the Num a dictionary
876 -- which can be free in g's rhs, and shared by both calls to g
877 isInheritablePred (ClassP _ _) = True
878 isInheritablePred other = False
880 isLinearPred :: TcPredType -> Bool
881 isLinearPred (IParam (Linear n) _) = True
882 isLinearPred other = False
885 --------------------- Equality predicates ---------------------------------
887 substEqSpec :: TvSubst -> [(TyVar,Type)] -> [(TcType,TcType)]
888 substEqSpec subst eq_spec = [ (substTyVar subst tv, substTy subst ty)
889 | (tv,ty) <- eq_spec]
892 --------------------- The stupid theta (sigh) ---------------------------------
895 dataConsStupidTheta :: [DataCon] -> ThetaType
896 -- Union the stupid thetas from all the specified constructors (non-empty)
897 -- All the constructors should have the same result type, modulo alpha conversion
898 -- The resulting ThetaType uses type variables from the *first* constructor in the list
900 -- It's here because it's used in MkId.mkRecordSelId, and in TcExpr
901 dataConsStupidTheta (con1:cons)
902 = nubBy tcEqPred all_preds
904 all_preds = dataConStupidTheta con1 ++ other_stupids
905 res_tys1 = dataConResTys con1
906 tvs1 = tyVarsOfTypes res_tys1
907 other_stupids = [ substPred subst pred
909 , let Just subst = tcMatchTys tvs1 res_tys1 (dataConResTys con)
910 , pred <- dataConStupidTheta con ]
911 dataConsStupidTheta [] = panic "dataConsStupidTheta"
915 %************************************************************************
917 \subsection{Predicates}
919 %************************************************************************
921 isSigmaTy returns true of any qualified type. It doesn't *necessarily* have
923 f :: (?x::Int) => Int -> Int
926 isSigmaTy :: Type -> Bool
927 isSigmaTy ty | Just ty' <- tcView ty = isSigmaTy ty'
928 isSigmaTy (ForAllTy tyvar ty) = True
929 isSigmaTy (FunTy a b) = isPredTy a
932 isOverloadedTy :: Type -> Bool
933 isOverloadedTy ty | Just ty' <- tcView ty = isOverloadedTy ty'
934 isOverloadedTy (ForAllTy tyvar ty) = isOverloadedTy ty
935 isOverloadedTy (FunTy a b) = isPredTy a
936 isOverloadedTy _ = False
938 isPredTy :: Type -> Bool -- Belongs in TcType because it does
939 -- not look through newtypes, or predtypes (of course)
940 isPredTy ty | Just ty' <- tcView ty = isPredTy ty'
941 isPredTy (PredTy sty) = True
946 isFloatTy = is_tc floatTyConKey
947 isDoubleTy = is_tc doubleTyConKey
948 isIntegerTy = is_tc integerTyConKey
949 isIntTy = is_tc intTyConKey
950 isBoolTy = is_tc boolTyConKey
951 isUnitTy = is_tc unitTyConKey
953 is_tc :: Unique -> Type -> Bool
954 -- Newtypes are opaque to this
955 is_tc uniq ty = case tcSplitTyConApp_maybe ty of
956 Just (tc, _) -> uniq == getUnique tc
961 %************************************************************************
965 %************************************************************************
968 deNoteType :: Type -> Type
969 -- Remove all *outermost* type synonyms and other notes
970 deNoteType ty | Just ty' <- tcView ty = deNoteType ty'
975 tcTyVarsOfType :: Type -> TcTyVarSet
976 -- Just the *TcTyVars* free in the type
977 -- (Types.tyVarsOfTypes finds all free TyVars)
978 tcTyVarsOfType (TyVarTy tv) = if isTcTyVar tv then unitVarSet tv
980 tcTyVarsOfType (TyConApp tycon tys) = tcTyVarsOfTypes tys
981 tcTyVarsOfType (NoteTy _ ty) = tcTyVarsOfType ty
982 tcTyVarsOfType (PredTy sty) = tcTyVarsOfPred sty
983 tcTyVarsOfType (FunTy arg res) = tcTyVarsOfType arg `unionVarSet` tcTyVarsOfType res
984 tcTyVarsOfType (AppTy fun arg) = tcTyVarsOfType fun `unionVarSet` tcTyVarsOfType arg
985 tcTyVarsOfType (ForAllTy tyvar ty) = tcTyVarsOfType ty `delVarSet` tyvar
986 -- We do sometimes quantify over skolem TcTyVars
988 tcTyVarsOfTypes :: [Type] -> TyVarSet
989 tcTyVarsOfTypes tys = foldr (unionVarSet.tcTyVarsOfType) emptyVarSet tys
991 tcTyVarsOfPred :: PredType -> TyVarSet
992 tcTyVarsOfPred (IParam _ ty) = tcTyVarsOfType ty
993 tcTyVarsOfPred (ClassP _ tys) = tcTyVarsOfTypes tys
996 Note [Silly type synonym]
997 ~~~~~~~~~~~~~~~~~~~~~~~~~
1000 What are the free tyvars of (T x)? Empty, of course!
1001 Here's the example that Ralf Laemmel showed me:
1002 foo :: (forall a. C u a -> C u a) -> u
1003 mappend :: Monoid u => u -> u -> u
1005 bar :: Monoid u => u
1006 bar = foo (\t -> t `mappend` t)
1007 We have to generalise at the arg to f, and we don't
1008 want to capture the constraint (Monad (C u a)) because
1009 it appears to mention a. Pretty silly, but it was useful to him.
1011 exactTyVarsOfType is used by the type checker to figure out exactly
1012 which type variables are mentioned in a type. It's also used in the
1013 smart-app checking code --- see TcExpr.tcIdApp
1016 exactTyVarsOfType :: TcType -> TyVarSet
1017 -- Find the free type variables (of any kind)
1018 -- but *expand* type synonyms. See Note [Silly type synonym] above.
1019 exactTyVarsOfType ty
1022 go ty | Just ty' <- tcView ty = go ty' -- This is the key line
1023 go (TyVarTy tv) = unitVarSet tv
1024 go (TyConApp tycon tys) = exactTyVarsOfTypes tys
1025 go (PredTy ty) = go_pred ty
1026 go (FunTy arg res) = go arg `unionVarSet` go res
1027 go (AppTy fun arg) = go fun `unionVarSet` go arg
1028 go (ForAllTy tyvar ty) = delVarSet (go ty) tyvar
1030 go_pred (IParam _ ty) = go ty
1031 go_pred (ClassP _ tys) = exactTyVarsOfTypes tys
1033 exactTyVarsOfTypes :: [TcType] -> TyVarSet
1034 exactTyVarsOfTypes tys = foldr (unionVarSet . exactTyVarsOfType) emptyVarSet tys
1037 Find the free tycons and classes of a type. This is used in the front
1038 end of the compiler.
1041 tyClsNamesOfType :: Type -> NameSet
1042 tyClsNamesOfType (TyVarTy tv) = emptyNameSet
1043 tyClsNamesOfType (TyConApp tycon tys) = unitNameSet (getName tycon) `unionNameSets` tyClsNamesOfTypes tys
1044 tyClsNamesOfType (NoteTy _ ty2) = tyClsNamesOfType ty2
1045 tyClsNamesOfType (PredTy (IParam n ty)) = tyClsNamesOfType ty
1046 tyClsNamesOfType (PredTy (ClassP cl tys)) = unitNameSet (getName cl) `unionNameSets` tyClsNamesOfTypes tys
1047 tyClsNamesOfType (FunTy arg res) = tyClsNamesOfType arg `unionNameSets` tyClsNamesOfType res
1048 tyClsNamesOfType (AppTy fun arg) = tyClsNamesOfType fun `unionNameSets` tyClsNamesOfType arg
1049 tyClsNamesOfType (ForAllTy tyvar ty) = tyClsNamesOfType ty
1051 tyClsNamesOfTypes tys = foldr (unionNameSets . tyClsNamesOfType) emptyNameSet tys
1053 tyClsNamesOfDFunHead :: Type -> NameSet
1054 -- Find the free type constructors and classes
1055 -- of the head of the dfun instance type
1056 -- The 'dfun_head_type' is because of
1057 -- instance Foo a => Baz T where ...
1058 -- The decl is an orphan if Baz and T are both not locally defined,
1059 -- even if Foo *is* locally defined
1060 tyClsNamesOfDFunHead dfun_ty
1061 = case tcSplitSigmaTy dfun_ty of
1062 (tvs,_,head_ty) -> tyClsNamesOfType head_ty
1064 classesOfTheta :: ThetaType -> [Class]
1065 -- Looks just for ClassP things; maybe it should check
1066 classesOfTheta preds = [ c | ClassP c _ <- preds ]
1070 %************************************************************************
1072 \subsection[TysWiredIn-ext-type]{External types}
1074 %************************************************************************
1076 The compiler's foreign function interface supports the passing of a
1077 restricted set of types as arguments and results (the restricting factor
1081 tcSplitIOType_maybe :: Type -> Maybe (TyCon, Type)
1082 -- (isIOType t) returns (Just (IO,t')) if t is of the form (IO t'), or
1083 -- some newtype wrapping thereof
1084 -- returns Nothing otherwise
1085 tcSplitIOType_maybe ty
1086 | Just (io_tycon, [io_res_ty]) <- tcSplitTyConApp_maybe ty,
1087 -- This split absolutely has to be a tcSplit, because we must
1088 -- see the IO type; and it's a newtype which is transparent to splitTyConApp.
1089 io_tycon `hasKey` ioTyConKey
1090 = Just (io_tycon, io_res_ty)
1092 | Just ty' <- coreView ty -- Look through non-recursive newtypes
1093 = tcSplitIOType_maybe ty'
1098 isFFITy :: Type -> Bool
1099 -- True for any TyCon that can possibly be an arg or result of an FFI call
1100 isFFITy ty = checkRepTyCon legalFFITyCon ty
1102 isFFIArgumentTy :: DynFlags -> Safety -> Type -> Bool
1103 -- Checks for valid argument type for a 'foreign import'
1104 isFFIArgumentTy dflags safety ty
1105 = checkRepTyCon (legalOutgoingTyCon dflags safety) ty
1107 isFFIExternalTy :: Type -> Bool
1108 -- Types that are allowed as arguments of a 'foreign export'
1109 isFFIExternalTy ty = checkRepTyCon legalFEArgTyCon ty
1111 isFFIImportResultTy :: DynFlags -> Type -> Bool
1112 isFFIImportResultTy dflags ty
1113 = checkRepTyCon (legalFIResultTyCon dflags) ty
1115 isFFIExportResultTy :: Type -> Bool
1116 isFFIExportResultTy ty = checkRepTyCon legalFEResultTyCon ty
1118 isFFIDynArgumentTy :: Type -> Bool
1119 -- The argument type of a foreign import dynamic must be Ptr, FunPtr, Addr,
1120 -- or a newtype of either.
1121 isFFIDynArgumentTy = checkRepTyConKey [ptrTyConKey, funPtrTyConKey]
1123 isFFIDynResultTy :: Type -> Bool
1124 -- The result type of a foreign export dynamic must be Ptr, FunPtr, Addr,
1125 -- or a newtype of either.
1126 isFFIDynResultTy = checkRepTyConKey [ptrTyConKey, funPtrTyConKey]
1128 isFFILabelTy :: Type -> Bool
1129 -- The type of a foreign label must be Ptr, FunPtr, Addr,
1130 -- or a newtype of either.
1131 isFFILabelTy = checkRepTyConKey [ptrTyConKey, funPtrTyConKey]
1133 isFFIDotnetTy :: DynFlags -> Type -> Bool
1134 isFFIDotnetTy dflags ty
1135 = checkRepTyCon (\ tc -> (legalFIResultTyCon dflags tc ||
1136 isFFIDotnetObjTy ty || isStringTy ty)) ty
1138 -- Support String as an argument or result from a .NET FFI call.
1140 case tcSplitTyConApp_maybe (repType ty) of
1142 | tc == listTyCon ->
1143 case tcSplitTyConApp_maybe (repType arg_ty) of
1144 Just (cc,[]) -> cc == charTyCon
1148 -- Support String as an argument or result from a .NET FFI call.
1149 isFFIDotnetObjTy ty =
1151 (_, t_ty) = tcSplitForAllTys ty
1153 case tcSplitTyConApp_maybe (repType t_ty) of
1154 Just (tc, [arg_ty]) | getName tc == objectTyConName -> True
1157 toDNType :: Type -> DNType
1159 | isStringTy ty = DNString
1160 | isFFIDotnetObjTy ty = DNObject
1161 | Just (tc,argTys) <- tcSplitTyConApp_maybe ty
1162 = case lookup (getUnique tc) dn_assoc of
1165 | tc `hasKey` ioTyConKey -> toDNType (head argTys)
1166 | otherwise -> pprPanic ("toDNType: unsupported .NET type")
1167 (pprType ty <+> parens (hcat (map pprType argTys)) <+> ppr tc)
1168 | otherwise = panic "toDNType" -- Is this right?
1170 dn_assoc :: [ (Unique, DNType) ]
1171 dn_assoc = [ (unitTyConKey, DNUnit)
1172 , (intTyConKey, DNInt)
1173 , (int8TyConKey, DNInt8)
1174 , (int16TyConKey, DNInt16)
1175 , (int32TyConKey, DNInt32)
1176 , (int64TyConKey, DNInt64)
1177 , (wordTyConKey, DNInt)
1178 , (word8TyConKey, DNWord8)
1179 , (word16TyConKey, DNWord16)
1180 , (word32TyConKey, DNWord32)
1181 , (word64TyConKey, DNWord64)
1182 , (floatTyConKey, DNFloat)
1183 , (doubleTyConKey, DNDouble)
1184 , (ptrTyConKey, DNPtr)
1185 , (funPtrTyConKey, DNPtr)
1186 , (charTyConKey, DNChar)
1187 , (boolTyConKey, DNBool)
1190 checkRepTyCon :: (TyCon -> Bool) -> Type -> Bool
1191 -- Look through newtypes
1192 -- Non-recursive ones are transparent to splitTyConApp,
1193 -- but recursive ones aren't. Manuel had:
1194 -- newtype T = MkT (Ptr T)
1195 -- and wanted it to work...
1196 checkRepTyCon check_tc ty
1197 | Just (tc,_) <- splitTyConApp_maybe (repType ty) = check_tc tc
1200 checkRepTyConKey :: [Unique] -> Type -> Bool
1201 -- Like checkRepTyCon, but just looks at the TyCon key
1202 checkRepTyConKey keys
1203 = checkRepTyCon (\tc -> tyConUnique tc `elem` keys)
1206 ----------------------------------------------
1207 These chaps do the work; they are not exported
1208 ----------------------------------------------
1211 legalFEArgTyCon :: TyCon -> Bool
1213 -- It's illegal to make foreign exports that take unboxed
1214 -- arguments. The RTS API currently can't invoke such things. --SDM 7/2000
1215 = boxedMarshalableTyCon tc
1217 legalFIResultTyCon :: DynFlags -> TyCon -> Bool
1218 legalFIResultTyCon dflags tc
1219 | tc == unitTyCon = True
1220 | otherwise = marshalableTyCon dflags tc
1222 legalFEResultTyCon :: TyCon -> Bool
1223 legalFEResultTyCon tc
1224 | tc == unitTyCon = True
1225 | otherwise = boxedMarshalableTyCon tc
1227 legalOutgoingTyCon :: DynFlags -> Safety -> TyCon -> Bool
1228 -- Checks validity of types going from Haskell -> external world
1229 legalOutgoingTyCon dflags safety tc
1230 = marshalableTyCon dflags tc
1232 legalFFITyCon :: TyCon -> Bool
1233 -- True for any TyCon that can possibly be an arg or result of an FFI call
1235 = isUnLiftedTyCon tc || boxedMarshalableTyCon tc || tc == unitTyCon
1237 marshalableTyCon dflags tc
1238 = (dopt Opt_GlasgowExts dflags && isUnLiftedTyCon tc)
1239 || boxedMarshalableTyCon tc
1241 boxedMarshalableTyCon tc
1242 = getUnique tc `elem` [ intTyConKey, int8TyConKey, int16TyConKey
1243 , int32TyConKey, int64TyConKey
1244 , wordTyConKey, word8TyConKey, word16TyConKey
1245 , word32TyConKey, word64TyConKey
1246 , floatTyConKey, doubleTyConKey
1247 , ptrTyConKey, funPtrTyConKey