\section[TcModule]{Typechecking a whole module}
\begin{code}
-#include "HsVersions.h"
-
module TcModule (
typecheckModule,
- TcResults(..),
- TcResultBinds(..),
- TcIfaceInfo(..),
- TcLocalTyConsAndClasses(..),
- TcSpecialiseRequests(..),
- TcDDumpDeriv(..)
+ TcResults,
+ TcDDumpDeriv
) where
-import Ubiq{-uitous-}
+#include "HsVersions.h"
-import HsSyn ( HsModule(..), HsBinds(..), Bind, HsExpr,
- TyDecl, SpecDataSig, ClassDecl, InstDecl,
- SpecInstSig, DefaultDecl, Sig, Fake, InPat,
- FixityDecl, IE, ImportDecl
- )
-import RnHsSyn ( RenamedHsModule(..), RenamedFixityDecl(..) )
-import TcHsSyn ( TypecheckedHsBinds(..), TypecheckedHsExpr(..),
- TcIdOcc(..), zonkBinds, zonkInst, zonkId )
+import CmdLineOpts ( opt_D_dump_tc, opt_D_dump_deriv )
+import HsSyn ( HsModule(..), HsBinds(..), MonoBinds(..), HsDecl(..) )
+import RnHsSyn ( RenamedHsModule )
+import TcHsSyn ( TcMonoBinds, TypecheckedMonoBinds, zonkTopBinds )
import TcMonad
-import Inst ( Inst, plusLIE )
-import TcBinds ( tcBindsAndThen )
+import Inst ( Inst, emptyLIE, plusLIE )
+import TcBinds ( tcTopBindsAndThen )
import TcClassDcl ( tcClassDecls2 )
import TcDefaults ( tcDefaults )
-import TcEnv ( tcExtendGlobalValEnv, getEnv_LocalIds,
- getEnv_TyCons, getEnv_Classes,
- tcLookupLocalValueByKey, tcLookupTyConByKey )
+import TcEnv ( TcIdOcc(..), tcExtendGlobalValEnv, tcExtendTyConEnv,
+ getEnv_TyCons, getEnv_Classes, tcLookupLocalValue,
+ tcLookupTyCon, initEnv )
+import TcExpr ( tcId )
import TcIfaceSig ( tcInterfaceSigs )
import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
-import TcInstUtil ( buildInstanceEnvs, InstInfo )
+import TcInstUtil ( buildInstanceEnvs, classDataCon, InstInfo )
import TcSimplify ( tcSimplifyTop )
import TcTyClsDecls ( tcTyAndClassDecls1 )
-
-import Bag ( listToBag )
-import Class ( GenClass )
-import ErrUtils ( Warning(..), Error(..) )
-import Id ( GenId, isDataCon, isMethodSelId, idType )
-import Maybes ( catMaybes )
-import Name ( isExported, isLocallyDefined )
-import PrelInfo ( unitTy, mkPrimIoTy )
-import Pretty
-import RnUtils ( RnEnv(..) )
-import TyCon ( TyCon )
-import Type ( mkSynTy )
+import TcTyDecls ( mkDataBinds )
+import TcType ( TcType, tcInstType )
+import TcKind ( TcKind, kindToTcKind )
+
+import RnMonad ( RnNameSupply(..) )
+import Bag ( isEmptyBag )
+import ErrUtils ( WarnMsg, ErrMsg,
+ pprBagOfErrors, dumpIfSet
+ )
+import Id ( idType, GenId )
+import Name ( Name, isLocallyDefined, pprModule, NamedThing(..) )
+import TyCon ( TyCon, tyConKind )
+import Class ( Class, classSelIds, classTyCon )
+import Type ( mkTyConApp, Type )
+import TyVar ( emptyTyVarEnv )
+import TysWiredIn ( unitTy )
+import PrelMods ( mAIN )
+import PrelInfo ( main_NAME, ioTyCon_NAME )
import Unify ( unifyTauTy )
-import UniqFM ( lookupUFM_Directly, lookupWithDefaultUFM_Directly,
- filterUFM, eltsUFM )
-import Unique ( iOTyConKey, mainIdKey, mainPrimIOIdKey )
+import Unique ( Unique )
+import UniqSupply ( UniqSupply )
import Util
-
-import FiniteMap ( emptyFM )
-tycon_specs = emptyFM
+import Bag ( Bag, isEmptyBag )
+import FiniteMap ( FiniteMap )
+import Outputable
\end{code}
Outside-world interface:
\begin{code}
+
-- Convenient type synonyms first:
type TcResults
- = (TcResultBinds,
- TcIfaceInfo,
- TcLocalTyConsAndClasses,
- TcSpecialiseRequests,
+ = (TypecheckedMonoBinds,
+ [TyCon], [Class],
+ Bag InstInfo, -- Instance declaration information
TcDDumpDeriv)
-type TcResultBinds
- = (TypecheckedHsBinds, -- record selector binds
- TypecheckedHsBinds, -- binds from class decls; does NOT
- -- include default-methods bindings
- TypecheckedHsBinds, -- binds from instance decls; INCLUDES
- -- class default-methods binds
- TypecheckedHsBinds, -- binds from value decls
-
- [(Id, TypecheckedHsExpr)]) -- constant instance binds
-
-type TcIfaceInfo -- things for the interface generator
- = ([Id], [TyCon], [Class], Bag InstInfo)
-
-type TcLocalTyConsAndClasses -- things defined in this module
- = ([TyCon], [Class])
- -- not sure the classes are used at all (ToDo)
-
-type TcSpecialiseRequests
- = FiniteMap TyCon [(Bool, [Maybe Type])]
- -- source tycon specialisation requests
-
-type TcDDumpDeriv
- = PprStyle -> Pretty
+type TcDDumpDeriv = SDoc
---------------
typecheckModule
:: UniqSupply
- -> RnEnv -- for renaming derivings
+ -> RnNameSupply
-> RenamedHsModule
- -> MaybeErr
- (TcResults, -- if all goes well...
- Bag Warning) -- (we can still get warnings)
- (Bag Error, -- if we had errors...
- Bag Warning)
-
-typecheckModule us rn_env mod
- = initTc us (tcModule rn_env mod)
+ -> IO (Maybe TcResults)
+
+typecheckModule us rn_name_supply mod
+ = let
+ (maybe_result, warns, errs) =
+ initTc us initEnv (tcModule rn_name_supply mod)
+ in
+ print_errs warns >>
+ print_errs errs >>
+
+ dumpIfSet opt_D_dump_tc "Typechecked"
+ (case maybe_result of
+ Just (binds, _, _, _, _) -> ppr binds
+ Nothing -> text "Typecheck failed") >>
+
+ dumpIfSet opt_D_dump_deriv "Derived instances"
+ (case maybe_result of
+ Just (_, _, _, _, dump_deriv) -> dump_deriv
+ Nothing -> empty) >>
+
+ return (if isEmptyBag errs then
+ maybe_result
+ else
+ Nothing)
+
+print_errs errs
+ | isEmptyBag errs = return ()
+ | otherwise = printErrs (pprBagOfErrors errs)
\end{code}
The internal monster:
\begin{code}
-tcModule :: RnEnv -- for renaming derivings
+tcModule :: RnNameSupply -- for renaming derivings
-> RenamedHsModule -- input
-> TcM s TcResults -- output
-tcModule rn_env
- (HsModule mod_name verion exports imports fixities
- ty_decls specdata_sigs cls_decls inst_decls specinst_sigs
- default_decls val_decls sigs src_loc)
-
- = ASSERT(null imports)
+tcModule rn_name_supply
+ (HsModule mod_name verion exports imports fixities decls src_loc)
+ = tcAddSrcLoc src_loc $ -- record where we're starting
- tcAddSrcLoc src_loc $ -- record where we're starting
-
- -- Tie the knot for inteface-file value declaration signatures
- -- This info is only used inside the knot for type-checking the
- -- pragmas, which is done lazily [ie failure just drops the pragma
+ fixTc (\ ~(unf_env ,_) ->
+ -- unf_env is used for type-checking interface pragmas
+ -- which is done lazily [ie failure just drops the pragma
-- without having any global-failure effect].
-
- fixTc (\ ~(_, _, _, _, _, _, sig_ids) ->
- tcExtendGlobalValEnv sig_ids (
-
- -- The knot for instance information. This isn't used at all
- -- till we type-check value declarations
- fixTc ( \ ~(rec_inst_mapper, _, _, _, _, _) ->
-
- -- Type-check the type and class decls
- --trace "tcTyAndClassDecls:" $
- tcTyAndClassDecls1 rec_inst_mapper ty_decls_bag cls_decls_bag
- `thenTc` \ (env, record_binds) ->
-
- -- Typecheck the instance decls, includes deriving
- tcSetEnv env (
- --trace "tcInstDecls:" $
- tcInstDecls1 inst_decls_bag specinst_sigs
- mod_name rn_env fixities
- ) `thenTc` \ (inst_info, deriv_binds, ddump_deriv) ->
-
- buildInstanceEnvs inst_info `thenTc` \ inst_mapper ->
-
- returnTc (inst_mapper, env, record_binds, inst_info, deriv_binds, ddump_deriv)
-
- ) `thenTc` \ (_, env, record_binds, inst_info, deriv_binds, ddump_deriv) ->
- tcSetEnv env (
-
- -- Default declarations
- tcDefaults default_decls `thenTc` \ defaulting_tys ->
- tcSetDefaultTys defaulting_tys ( -- for the iface sigs...
+ --
+ -- unf_env is also used to get the pragam info for dfuns.
+
+ -- The knot for instance information. This isn't used at all
+ -- till we type-check value declarations
+ fixTc ( \ ~(rec_inst_mapper, _, _, _, _) ->
+
+ -- Type-check the type and class decls
+ -- trace "tcTyAndClassDecls:" $
+ tcTyAndClassDecls1 unf_env rec_inst_mapper decls `thenTc` \ env ->
+
+ -- trace "tc3" $
+ -- Typecheck the instance decls, includes deriving
+ tcSetEnv env (
+ -- trace "tcInstDecls:" $
+ tcInstDecls1 unf_env decls mod_name rn_name_supply
+ ) `thenTc` \ (inst_info, deriv_binds, ddump_deriv) ->
+
+ -- trace "tc4" $
+ buildInstanceEnvs inst_info `thenNF_Tc` \ inst_mapper ->
+
+ returnTc (inst_mapper, env, inst_info, deriv_binds, ddump_deriv)
+
+ -- End of inner fix loop
+ ) `thenTc` \ (_, env, inst_info, deriv_binds, ddump_deriv) ->
+
+ -- trace "tc5" $
+ tcSetEnv env $
+
+ -- Default declarations
+ tcDefaults decls `thenTc` \ defaulting_tys ->
+ tcSetDefaultTys defaulting_tys $
+
+ -- Create any necessary record selector Ids and their bindings
+ -- "Necessary" includes data and newtype declarations
+ let
+ tycons = getEnv_TyCons env
+ classes = getEnv_Classes env
+ local_tycons = filter isLocallyDefined tycons
+ local_classes = filter isLocallyDefined classes
+ in
+ mkDataBinds tycons `thenTc` \ (data_ids, data_binds) ->
+
+ -- Extend the global value environment with
+ -- (a) constructors
+ -- (b) record selectors
+ -- (c) class op selectors
+ -- (d) default-method ids
+ tcExtendGlobalValEnv data_ids $
+ tcExtendGlobalValEnv (concat (map classSelIds classes)) $
+
+ -- Extend the TyCon envt with the tycons corresponding to
+ -- the classes, and the global value environment with the
+ -- corresponding data cons.
+ -- They are mentioned in types in interface files.
+ tcExtendGlobalValEnv (map classDataCon classes) $
+ tcExtendTyConEnv [ (getName tycon, (kindToTcKind (tyConKind tycon), Nothing, tycon))
+ | clas <- classes,
+ let tycon = classTyCon clas
+ ] $
-- Interface type signatures
-- We tie a knot so that the Ids read out of interfaces are in scope
-- What we rely on is that pragmas are typechecked lazily; if
-- any type errors are found (ie there's an inconsistency)
-- we silently discard the pragma
- tcInterfaceSigs sigs `thenTc` \ sig_ids ->
-
- returnTc (env, inst_info, record_binds, deriv_binds, ddump_deriv, defaulting_tys, sig_ids)
-
- )))) `thenTc` \ (env, inst_info, record_binds, deriv_binds, ddump_deriv, defaulting_tys, _) ->
+ tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
+ tcExtendGlobalValEnv sig_ids $
- tcSetEnv env ( -- to the end...
- tcSetDefaultTys defaulting_tys ( -- ditto
-- Value declarations next.
-- We also typecheck any extra binds that came out of the "deriving" process
- --trace "tcBinds:" $
- tcBindsAndThen
- (\ binds1 (binds2, thing) -> (binds1 `ThenBinds` binds2, thing))
- (val_decls `ThenBinds` deriv_binds)
- ( -- Second pass over instance declarations,
- -- to compile the bindings themselves.
- tcInstDecls2 inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
- tcClassDecls2 cls_decls_bag `thenNF_Tc` \ (lie_clasdecls, cls_binds) ->
- tcGetEnv `thenNF_Tc` \ env ->
- returnTc ( (EmptyBinds, (inst_binds, cls_binds, env)),
- lie_instdecls `plusLIE` lie_clasdecls,
- () ))
-
- `thenTc` \ ((val_binds, (inst_binds, cls_binds, final_env)), lie_alldecls, _) ->
-
- checkTopLevelIds mod_name final_env `thenTc_`
-
- -- Deal with constant or ambiguous InstIds. How could
- -- there be ambiguous ones? They can only arise if a
- -- top-level decl falls under the monomorphism
- -- restriction, and no subsequent decl instantiates its
- -- type. (Usually, ambiguous type variables are resolved
- -- during the generalisation step.)
- tcSimplifyTop lie_alldecls `thenTc` \ const_insts ->
- let
- localids = getEnv_LocalIds final_env
- tycons = getEnv_TyCons final_env
- classes = getEnv_Classes final_env
-
- local_tycons = filter isLocallyDefined tycons
- local_classes = filter isLocallyDefined classes
-
- exported_ids = [v | v <- localids,
- isExported v && not (isDataCon v) && not (isMethodSelId v)]
- in
- -- Backsubstitution. Monomorphic top-level decls may have
- -- been instantiated by subsequent decls, and the final
- -- simplification step may have instantiated some
- -- ambiguous types. So, sadly, we need to back-substitute
- -- over the whole bunch of bindings.
- zonkBinds record_binds `thenNF_Tc` \ record_binds' ->
- zonkBinds val_binds `thenNF_Tc` \ val_binds' ->
- zonkBinds inst_binds `thenNF_Tc` \ inst_binds' ->
- zonkBinds cls_binds `thenNF_Tc` \ cls_binds' ->
- mapNF_Tc zonkInst const_insts `thenNF_Tc` \ const_insts' ->
- mapNF_Tc (zonkId.TcId) exported_ids `thenNF_Tc` \ exported_ids' ->
-
- -- FINISHED AT LAST
- returnTc (
- (record_binds', cls_binds', inst_binds', val_binds', const_insts'),
-
- -- the next collection is just for mkInterface
- (exported_ids', tycons, classes, inst_info),
-
- (local_tycons, local_classes),
-
- tycon_specs,
-
- ddump_deriv
- )))
- where
- ty_decls_bag = listToBag ty_decls
- cls_decls_bag = listToBag cls_decls
- inst_decls_bag = listToBag inst_decls
-
-\end{code}
+ -- trace "tcBinds:" $
+ tcTopBindsAndThen
+ (\ is_rec binds1 (binds2, thing) -> (binds1 `AndMonoBinds` binds2, thing))
+ (get_val_decls decls `ThenBinds` deriv_binds)
+ ( tcGetEnv `thenNF_Tc` \ env ->
+ returnTc ((EmptyMonoBinds, env), emptyLIE)
+ ) `thenTc` \ ((val_binds, final_env), lie_valdecls) ->
+ tcSetEnv final_env $
-%************************************************************************
-%* *
-\subsection{Error checking code}
-%* *
-%************************************************************************
-
+ -- Second pass over class and instance declarations,
+ -- to compile the bindings themselves.
+ -- trace "tc8" $
+ tcInstDecls2 inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
+ tcClassDecls2 decls `thenNF_Tc` \ (lie_clasdecls, cls_binds) ->
+
+
+
+ -- Check that "main" has the right signature
+ tcCheckMainSig mod_name `thenTc_`
+
+ -- Deal with constant or ambiguous InstIds. How could
+ -- there be ambiguous ones? They can only arise if a
+ -- top-level decl falls under the monomorphism
+ -- restriction, and no subsequent decl instantiates its
+ -- type. (Usually, ambiguous type variables are resolved
+ -- during the generalisation step.)
+ -- trace "tc9" $
+ let
+ lie_alldecls = lie_valdecls `plusLIE` lie_instdecls `plusLIE` lie_clasdecls
+ in
+ tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
+
+
+ -- Backsubstitution. This must be done last.
+ -- Even tcCheckMainSig and tcSimplifyTop may do some unification.
+ let
+ all_binds = data_binds `AndMonoBinds`
+ val_binds `AndMonoBinds`
+ inst_binds `AndMonoBinds`
+ cls_binds `AndMonoBinds`
+ const_inst_binds
+ in
+ zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', really_final_env) ->
+
+ returnTc (really_final_env,
+ (all_binds', local_tycons, local_classes, inst_info, ddump_deriv))
+
+ -- End of outer fix loop
+ ) `thenTc` \ (final_env, stuff) ->
+ returnTc stuff
+
+get_val_decls decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
+\end{code}
-checkTopLevelIds checks that Main.main or Main.mainPrimIO has correct type.
\begin{code}
-checkTopLevelIds :: FAST_STRING -> TcEnv s -> TcM s ()
-checkTopLevelIds mod final_env
- | mod /= SLIT("Main")
- = returnTc ()
+tcCheckMainSig mod_name
+ | mod_name /= mAIN
+ = returnTc () -- A non-main module
| otherwise
- = tcSetEnv final_env (
- tcLookupLocalValueByKey mainIdKey `thenNF_Tc` \ maybe_main ->
- tcLookupLocalValueByKey mainPrimIOIdKey `thenNF_Tc` \ maybe_prim ->
- tcLookupTyConByKey iOTyConKey `thenNF_Tc` \ io_tc ->
-
- case (maybe_main, maybe_prim) of
- (Just main, Nothing) -> tcAddErrCtxt mainCtxt $
- unifyTauTy (mkSynTy io_tc [unitTy])
- (idType main)
-
- (Nothing, Just prim) -> tcAddErrCtxt primCtxt $
- unifyTauTy (mkPrimIoTy unitTy)
- (idType prim)
-
- (Just _ , Just _ ) -> failTc mainBothIdErr
- (Nothing, Nothing) -> failTc mainNoneIdErr
- )
-
-mainCtxt sty
- = ppStr "main should have type IO ()"
-
-primCtxt sty
- = ppStr "mainPrimIO should have type PrimIO ()"
-
-mainBothIdErr sty
- = ppStr "module Main contains definitions for both main and mainPrimIO"
-
-mainNoneIdErr sty
- = ppStr "module Main does not contain a definition for main (or mainPrimIO)"
+ = -- Check that main is defined
+ tcLookupTyCon ioTyCon_NAME `thenTc` \ (_,_,ioTyCon) ->
+ tcLookupLocalValue main_NAME `thenNF_Tc` \ maybe_main_id ->
+ case maybe_main_id of {
+ Nothing -> failWithTc noMainErr ;
+ Just main_id ->
+
+ -- Check that it has the right type (or a more general one)
+ let
+ expected_ty = mkTyConApp ioTyCon [unitTy]
+ in
+ tcInstType emptyTyVarEnv expected_ty `thenNF_Tc` \ expected_tau ->
+ tcId main_NAME `thenNF_Tc` \ (_, lie, main_tau) ->
+ tcSetErrCtxt mainTyCheckCtxt $
+ unifyTauTy expected_tau
+ main_tau `thenTc_`
+ checkTc (isEmptyBag lie) (mainTyMisMatch expected_ty (idType main_id))
+ }
+
+
+mainTyCheckCtxt
+ = hsep [ptext SLIT("When checking that"), ppr main_NAME, ptext SLIT("has the required type")]
+
+noMainErr
+ = hsep [ptext SLIT("Module"), quotes (pprModule mAIN),
+ ptext SLIT("must include a definition for"), quotes (ppr main_NAME)]
+
+mainTyMisMatch :: Type -> TcType s -> ErrMsg
+mainTyMisMatch expected actual
+ = hang (hsep [ppr main_NAME, ptext SLIT("has the wrong type")])
+ 4 (vcat [
+ hsep [ptext SLIT("Expected:"), ppr expected],
+ hsep [ptext SLIT("Inferred:"), ppr actual]
+ ])
\end{code}
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