4 TyThing(..), TyThingDetails(..), TcTyThing(..),
6 -- Getting stuff from the environment
8 tcEnvTyCons, tcEnvClasses, tcEnvIds, tcEnvTcIds, tcEnvTyVars,
11 -- Instance environment, and InstInfo type
12 tcGetInstEnv, tcSetInstEnv,
13 InstInfo(..), pprInstInfo,
14 simpleInstInfoTy, simpleInstInfoTyCon,
17 tcExtendGlobalEnv, tcExtendGlobalValEnv,
18 tcLookupTyCon, tcLookupClass, tcLookupGlobalId, tcLookupDataCon,
19 tcLookupGlobal_maybe, tcLookupGlobal, tcLookupSyntaxId, tcLookupSyntaxName,
22 tcExtendKindEnv, tcLookupLocalIds,
23 tcExtendTyVarEnv, tcExtendTyVarEnvForMeths,
24 tcExtendLocalValEnv, tcLookup, tcLookup_maybe,
26 -- Global type variables
27 tcGetGlobalTyVars, tcExtendGlobalTyVars,
29 -- Random useful things
30 RecTcEnv, tcAddImportedIdInfo, tcLookupRecId, tcLookupRecId_maybe,
33 newLocalId, newSpecPragmaId,
37 isLocalThing, tcSetEnv
40 #include "HsVersions.h"
42 import RnHsSyn ( RenamedMonoBinds, RenamedSig )
44 import TcType ( TcKind, TcType, TcTyVar, TcTyVarSet,
47 import Id ( idName, mkUserLocal, isDataConWrapId_maybe )
48 import IdInfo ( constantIdInfo )
49 import MkId ( mkSpecPragmaId )
50 import Var ( TyVar, Id, idType, lazySetIdInfo, idInfo )
53 tyVarsOfTypes, splitDFunTy,
54 getDFunTyKey, tyConAppTyCon
56 import DataCon ( DataCon )
57 import TyCon ( TyCon )
58 import Class ( Class, ClassOpItem, ClassContext )
59 import Name ( Name, OccName, NamedThing(..),
60 nameOccName, getSrcLoc, mkLocalName, isLocalName,
61 nameIsLocalOrFrom, nameModule_maybe
63 import Name ( NameEnv, lookupNameEnv, nameEnvElts, extendNameEnvList, emptyNameEnv )
64 import OccName ( mkDFunOcc, occNameString )
65 import HscTypes ( DFunId, TypeEnv, HomeSymbolTable, PackageTypeEnv )
66 import Module ( Module )
67 import InstEnv ( InstEnv, emptyInstEnv )
68 import HscTypes ( lookupType, TyThing(..) )
69 import Util ( zipEqual )
70 import SrcLoc ( SrcLoc )
71 import qualified PrelNames
74 import IOExts ( newIORef )
77 %************************************************************************
81 %************************************************************************
84 type TcId = Id -- Type may be a TcType
89 tcSyntaxMap :: PrelNames.SyntaxMap, -- The syntax map (usually the identity)
91 tcGST :: Name -> Maybe TyThing, -- The type environment at the moment we began this compilation
93 tcInsts :: InstEnv, -- All instances (both imported and in this module)
95 tcGEnv :: TypeEnv, -- The global type environment we've accumulated while
96 {- NameEnv TyThing-} -- compiling this module:
97 -- types and classes (both imported and local)
99 -- (Ids defined in this module are in the local envt)
101 tcLEnv :: NameEnv TcTyThing, -- The local type environment: Ids and TyVars
102 -- defined in this module
104 tcTyVars :: TcRef TcTyVarSet -- The "global tyvars"
105 -- Namely, the in-scope TyVars bound in tcLEnv, plus the tyvars
106 -- mentioned in the types of Ids bound in tcLEnv
107 -- Why mutable? see notes with tcGetGlobalTyVars
112 The Global-Env/Local-Env story
113 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
114 During type checking, we keep in the GlobalEnv
115 * All types and classes
116 * All Ids derived from types and classes (constructors, selectors)
119 At the end of type checking, we zonk the local bindings,
120 and as we do so we add to the GlobalEnv
121 * Locally defined top-level Ids
123 Why? Because they are now Ids not TcIds. This final GlobalEnv is
125 a) fed back (via the knot) to typechecking the
126 unfoldings of interface signatures
128 b) used to augment the GlobalSymbolTable
133 = AGlobal TyThing -- Used only in the return type of a lookup
134 | ATcId TcId -- Ids defined in this module
135 | ATyVar TyVar -- Type variables
136 | AThing TcKind -- Used temporarily, during kind checking
137 -- Here's an example of how the AThing guy is used
138 -- Suppose we are checking (forall a. T a Int):
139 -- 1. We first bind (a -> AThink kv), where kv is a kind variable.
140 -- 2. Then we kind-check the (T a Int) part.
141 -- 3. Then we zonk the kind variable.
142 -- 4. Now we know the kind for 'a', and we add (a -> ATyVar a::K) to the environment
144 initTcEnv :: PrelNames.SyntaxMap -> HomeSymbolTable -> PackageTypeEnv -> IO TcEnv
145 initTcEnv syntax_map hst pte
146 = do { gtv_var <- newIORef emptyVarSet ;
147 return (TcEnv { tcSyntaxMap = syntax_map,
149 tcGEnv = emptyNameEnv,
150 tcInsts = emptyInstEnv,
151 tcLEnv = emptyNameEnv,
155 lookup name | isLocalName name = Nothing
156 | otherwise = lookupType hst pte name
159 tcEnvClasses env = [cl | AClass cl <- nameEnvElts (tcGEnv env)]
160 tcEnvTyCons env = [tc | ATyCon tc <- nameEnvElts (tcGEnv env)]
161 tcEnvIds env = [id | AnId id <- nameEnvElts (tcGEnv env)]
162 tcEnvTyVars env = [tv | ATyVar tv <- nameEnvElts (tcLEnv env)]
163 tcEnvTcIds env = [id | ATcId id <- nameEnvElts (tcLEnv env)]
165 getTcGEnv (TcEnv { tcGEnv = genv }) = genv
167 -- This data type is used to help tie the knot
168 -- when type checking type and class declarations
169 data TyThingDetails = SynTyDetails Type
170 | DataTyDetails ClassContext [DataCon] [Id]
171 | ClassDetails ClassContext [Id] [ClassOpItem] DataCon
175 %************************************************************************
177 \subsection{Basic lookups}
179 %************************************************************************
182 lookup_global :: TcEnv -> Name -> Maybe TyThing
183 -- Try the global envt and then the global symbol table
184 lookup_global env name
185 = case lookupNameEnv (tcGEnv env) name of
186 Just thing -> Just thing
187 Nothing -> tcGST env name
189 lookup_local :: TcEnv -> Name -> Maybe TcTyThing
190 -- Try the local envt and then try the global
191 lookup_local env name
192 = case lookupNameEnv (tcLEnv env) name of
193 Just thing -> Just thing
194 Nothing -> case lookup_global env name of
195 Just thing -> Just (AGlobal thing)
200 type RecTcEnv = TcEnv
201 -- This environment is used for getting the 'right' IdInfo
202 -- on imported things and for looking up Ids in unfoldings
203 -- The environment doesn't have any local Ids in it
205 tcAddImportedIdInfo :: RecTcEnv -> Id -> Id
206 tcAddImportedIdInfo env id
207 = id `lazySetIdInfo` new_info
208 -- The Id must be returned without a data dependency on maybe_id
210 new_info = case tcLookupRecId_maybe env (idName id) of
211 Nothing -> pprTrace "tcAddIdInfo" (ppr id) constantIdInfo
212 Just imported_id -> idInfo imported_id
213 -- ToDo: could check that types are the same
215 tcLookupRecId_maybe :: RecTcEnv -> Name -> Maybe Id
216 tcLookupRecId_maybe env name = case lookup_global env name of
217 Just (AnId id) -> Just id
220 tcLookupRecId :: RecTcEnv -> Name -> Id
221 tcLookupRecId env name = case lookup_global env name of
223 Nothing -> pprPanic "tcLookupRecId" (ppr name)
226 %************************************************************************
228 \subsection{Making new Ids}
230 %************************************************************************
235 newLocalId :: OccName -> TcType -> SrcLoc -> NF_TcM TcId
236 newLocalId name ty loc
237 = tcGetUnique `thenNF_Tc` \ uniq ->
238 returnNF_Tc (mkUserLocal name uniq ty loc)
240 newSpecPragmaId :: Name -> TcType -> NF_TcM TcId
241 newSpecPragmaId name ty
242 = tcGetUnique `thenNF_Tc` \ uniq ->
243 returnNF_Tc (mkSpecPragmaId (nameOccName name) uniq ty (getSrcLoc name))
246 Make a name for the dict fun for an instance decl.
247 It's a *local* name for the moment. The CoreTidy pass
251 newDFunName :: Class -> [Type] -> SrcLoc -> NF_TcM Name
252 newDFunName clas (ty:_) loc
253 = tcGetUnique `thenNF_Tc` \ uniq ->
254 returnNF_Tc (mkLocalName uniq (mkDFunOcc dfun_string) loc)
256 -- Any string that is somewhat unique will do
257 dfun_string = occNameString (getOccName clas) ++ occNameString (getDFunTyKey ty)
259 newDFunName clas [] loc = pprPanic "newDFunName" (ppr clas <+> ppr loc)
263 isLocalThing :: NamedThing a => Module -> a -> Bool
264 isLocalThing mod thing = nameIsLocalOrFrom mod (getName thing)
267 %************************************************************************
269 \subsection{The global environment}
271 %************************************************************************
274 tcExtendGlobalEnv :: [TyThing] -> TcM r -> TcM r
275 tcExtendGlobalEnv things thing_inside
276 = tcGetEnv `thenNF_Tc` \ env ->
278 ge' = extendNameEnvList (tcGEnv env) [(getName thing, thing) | thing <- things]
280 tcSetEnv (env {tcGEnv = ge'}) thing_inside
282 tcExtendGlobalValEnv :: [Id] -> TcM a -> TcM a
283 tcExtendGlobalValEnv ids thing_inside
284 = tcGetEnv `thenNF_Tc` \ env ->
286 ge' = extendNameEnvList (tcGEnv env) [(getName id, AnId id) | id <- ids]
288 tcSetEnv (env {tcGEnv = ge'}) thing_inside
293 tcLookupGlobal_maybe :: Name -> NF_TcM (Maybe TyThing)
294 tcLookupGlobal_maybe name
295 = tcGetEnv `thenNF_Tc` \ env ->
296 returnNF_Tc (lookup_global env name)
299 A variety of global lookups, when we know what we are looking for.
302 tcLookupGlobal :: Name -> NF_TcM TyThing
304 = tcLookupGlobal_maybe name `thenNF_Tc` \ maybe_thing ->
306 Just thing -> returnNF_Tc thing
307 other -> notFound "tcLookupGlobal" name
309 tcLookupGlobalId :: Name -> NF_TcM Id
310 tcLookupGlobalId name
311 = tcLookupGlobal_maybe name `thenNF_Tc` \ maybe_id ->
313 Just (AnId id) -> returnNF_Tc id
314 other -> notFound "tcLookupGlobalId" name
316 tcLookupDataCon :: Name -> TcM DataCon
317 tcLookupDataCon con_name
318 = tcLookupGlobalId con_name `thenNF_Tc` \ con_id ->
319 case isDataConWrapId_maybe con_id of
320 Just data_con -> returnTc data_con
321 Nothing -> failWithTc (badCon con_id)
324 tcLookupClass :: Name -> NF_TcM Class
326 = tcLookupGlobal_maybe name `thenNF_Tc` \ maybe_clas ->
328 Just (AClass clas) -> returnNF_Tc clas
329 other -> notFound "tcLookupClass" name
331 tcLookupTyCon :: Name -> NF_TcM TyCon
333 = tcLookupGlobal_maybe name `thenNF_Tc` \ maybe_tc ->
335 Just (ATyCon tc) -> returnNF_Tc tc
336 other -> notFound "tcLookupTyCon" name
338 tcLookupLocalIds :: [Name] -> NF_TcM [TcId]
340 = tcGetEnv `thenNF_Tc` \ env ->
341 returnNF_Tc (map (lookup (tcLEnv env)) ns)
343 lookup lenv name = case lookupNameEnv lenv name of
344 Just (ATcId id) -> id
345 other -> pprPanic "tcLookupLocalIds" (ppr name)
347 tcLookupSyntaxId :: Name -> NF_TcM Id
348 -- Lookup a name like PrelNum.fromInt, and return the corresponding Id,
349 -- after mapping through the SyntaxMap. This may give us the Id for
350 -- (say) MyPrelude.fromInteger
351 tcLookupSyntaxId name
352 = tcGetEnv `thenNF_Tc` \ env ->
353 returnNF_Tc (case lookup_global env (tcSyntaxMap env name) of
355 other -> pprPanic "tcLookupSyntaxId" (ppr name))
357 tcLookupSyntaxName :: Name -> NF_TcM Name
358 tcLookupSyntaxName name
359 = tcGetEnv `thenNF_Tc` \ env ->
360 returnNF_Tc (tcSyntaxMap env name)
364 %************************************************************************
366 \subsection{The local environment}
368 %************************************************************************
371 tcLookup_maybe :: Name -> NF_TcM (Maybe TcTyThing)
373 = tcGetEnv `thenNF_Tc` \ env ->
374 returnNF_Tc (lookup_local env name)
376 tcLookup :: Name -> NF_TcM TcTyThing
378 = tcLookup_maybe name `thenNF_Tc` \ maybe_thing ->
380 Just thing -> returnNF_Tc thing
381 other -> notFound "tcLookup" name
382 -- Extract the IdInfo from an IfaceSig imported from an interface file
387 tcExtendKindEnv :: [(Name,TcKind)] -> TcM r -> TcM r
388 tcExtendKindEnv pairs thing_inside
389 = tcGetEnv `thenNF_Tc` \ env ->
391 le' = extendNameEnvList (tcLEnv env) [(n, AThing k) | (n,k) <- pairs]
392 -- No need to extend global tyvars for kind checking
394 tcSetEnv (env {tcLEnv = le'}) thing_inside
396 tcExtendTyVarEnv :: [TyVar] -> TcM r -> TcM r
397 tcExtendTyVarEnv tyvars thing_inside
398 = tcGetEnv `thenNF_Tc` \ env@(TcEnv {tcLEnv = le, tcTyVars = gtvs}) ->
400 le' = extendNameEnvList le [ (getName tv, ATyVar tv) | tv <- tyvars]
401 new_tv_set = mkVarSet tyvars
403 -- It's important to add the in-scope tyvars to the global tyvar set
405 -- f (x::r) = let g y = y::r in ...
406 -- Here, g mustn't be generalised. This is also important during
407 -- class and instance decls, when we mustn't generalise the class tyvars
408 -- when typechecking the methods.
409 tc_extend_gtvs gtvs new_tv_set `thenNF_Tc` \ gtvs' ->
410 tcSetEnv (env {tcLEnv = le', tcTyVars = gtvs'}) thing_inside
412 -- This variant, tcExtendTyVarEnvForMeths, takes *two* bunches of tyvars:
413 -- the signature tyvars contain the original names
414 -- the instance tyvars are what those names should be mapped to
415 -- It's needed when typechecking the method bindings of class and instance decls
416 -- It does *not* extend the global tyvars; tcMethodBind does that for itself
418 tcExtendTyVarEnvForMeths :: [TyVar] -> [TcTyVar] -> TcM r -> TcM r
419 tcExtendTyVarEnvForMeths sig_tyvars inst_tyvars thing_inside
420 = tcGetEnv `thenNF_Tc` \ env ->
422 le' = extendNameEnvList (tcLEnv env) stuff
423 stuff = [ (getName sig_tv, ATyVar inst_tv)
424 | (sig_tv, inst_tv) <- zipEqual "tcMeth" sig_tyvars inst_tyvars
427 tcSetEnv (env {tcLEnv = le'}) thing_inside
432 tcExtendLocalValEnv :: [(Name,TcId)] -> TcM a -> TcM a
433 tcExtendLocalValEnv names_w_ids thing_inside
434 = tcGetEnv `thenNF_Tc` \ env ->
436 extra_global_tyvars = tyVarsOfTypes [idType id | (name,id) <- names_w_ids]
437 extra_env = [(name, ATcId id) | (name,id) <- names_w_ids]
438 le' = extendNameEnvList (tcLEnv env) extra_env
440 tc_extend_gtvs (tcTyVars env) extra_global_tyvars `thenNF_Tc` \ gtvs' ->
441 tcSetEnv (env {tcLEnv = le', tcTyVars = gtvs'}) thing_inside
445 %************************************************************************
447 \subsection{The global tyvars}
449 %************************************************************************
452 tcExtendGlobalTyVars extra_global_tvs thing_inside
453 = tcGetEnv `thenNF_Tc` \ env ->
454 tc_extend_gtvs (tcTyVars env) extra_global_tvs `thenNF_Tc` \ gtvs' ->
455 tcSetEnv (env {tcTyVars = gtvs'}) thing_inside
457 tc_extend_gtvs gtvs extra_global_tvs
458 = tcReadMutVar gtvs `thenNF_Tc` \ global_tvs ->
459 tcNewMutVar (global_tvs `unionVarSet` extra_global_tvs)
462 @tcGetGlobalTyVars@ returns a fully-zonked set of tyvars free in the environment.
463 To improve subsequent calls to the same function it writes the zonked set back into
467 tcGetGlobalTyVars :: NF_TcM TcTyVarSet
469 = tcGetEnv `thenNF_Tc` \ (TcEnv {tcTyVars = gtv_var}) ->
470 tcReadMutVar gtv_var `thenNF_Tc` \ gbl_tvs ->
471 zonkTcTyVarsAndFV (varSetElems gbl_tvs) `thenNF_Tc` \ gbl_tvs' ->
472 tcWriteMutVar gtv_var gbl_tvs' `thenNF_Tc_`
477 %************************************************************************
479 \subsection{The instance environment}
481 %************************************************************************
484 tcGetInstEnv :: NF_TcM InstEnv
485 tcGetInstEnv = tcGetEnv `thenNF_Tc` \ env ->
486 returnNF_Tc (tcInsts env)
488 tcSetInstEnv :: InstEnv -> TcM a -> TcM a
489 tcSetInstEnv ie thing_inside
490 = tcGetEnv `thenNF_Tc` \ env ->
491 tcSetEnv (env {tcInsts = ie}) thing_inside
495 %************************************************************************
497 \subsection{The InstInfo type}
499 %************************************************************************
501 The InstInfo type summarises the information in an instance declaration
503 instance c => k (t tvs) where b
508 iDFunId :: DFunId, -- The dfun id
509 iBinds :: RenamedMonoBinds, -- Bindings, b
510 iPrags :: [RenamedSig] -- User pragmas recorded for generating specialised instances
513 pprInstInfo info = vcat [ptext SLIT("InstInfo:") <+> ppr (idType (iDFunId info)),
514 nest 4 (ppr (iBinds info))]
516 simpleInstInfoTy :: InstInfo -> Type
517 simpleInstInfoTy info = case splitDFunTy (idType (iDFunId info)) of
518 (_, _, _, [ty]) -> ty
520 simpleInstInfoTyCon :: InstInfo -> TyCon
521 -- Gets the type constructor for a simple instance declaration,
522 -- i.e. one of the form instance (...) => C (T a b c) where ...
523 simpleInstInfoTyCon inst = tyConAppTyCon (simpleInstInfoTy inst)
527 %************************************************************************
531 %************************************************************************
534 badCon con_id = quotes (ppr con_id) <+> ptext SLIT("is not a data constructor")
536 notFound wheRe name = failWithTc (text wheRe <> colon <+> quotes (ppr name) <+>
537 ptext SLIT("is not in scope"))