\section[TcModule]{Typechecking a whole module}
\begin{code}
-#include "HsVersions.h"
-
module TcModule (
typecheckModule,
- SYN_IE(TcResults),
- SYN_IE(TcResultBinds),
- SYN_IE(TcSpecialiseRequests),
- SYN_IE(TcDDumpDeriv)
+ TcResults,
+ TcDDumpDeriv
) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
-import HsSyn ( HsDecl(..), HsModule(..), HsBinds(..), Bind, HsExpr,
- TyDecl, SpecDataSig, ClassDecl, InstDecl, IfaceSig,
- SpecInstSig, DefaultDecl, Sig, Fake, InPat,
- FixityDecl, IE, ImportDecl
- )
-import RnHsSyn ( SYN_IE(RenamedHsModule), RenamedFixityDecl(..) )
-import TcHsSyn ( SYN_IE(TypecheckedHsBinds), SYN_IE(TypecheckedHsExpr),
- TcIdOcc(..), zonkBinds, zonkDictBinds )
+import CmdLineOpts ( opt_D_dump_tc, opt_D_dump_deriv )
+import HsSyn ( HsModule(..), HsBinds(..), MonoBinds(..), HsDecl(..) )
+import RnHsSyn ( RenamedHsModule, RenamedFixityDecl(..) )
+import TcHsSyn ( TypecheckedHsBinds, TypecheckedHsExpr,
+ TypecheckedDictBinds, 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,
+import TcEnv ( TcIdOcc(..), tcExtendGlobalValEnv, tcExtendTyConEnv, getEnv_LocalIds,
getEnv_TyCons, getEnv_Classes, tcLookupLocalValue,
tcLookupLocalValueByKey, tcLookupTyCon,
tcLookupGlobalValueByKeyMaybe )
-import SpecEnv ( SpecEnv )
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 TcTyDecls ( mkDataBinds )
-import TcType ( SYN_IE(TcType), tcInstType )
-import TcKind ( TcKind )
+import TcType ( TcType, tcInstType )
+import TcKind ( TcKind, kindToTcKind )
import RnMonad ( RnNameSupply(..) )
-import Bag ( listToBag )
-import Class ( GenClass, classSelIds )
-import ErrUtils ( SYN_IE(Warning), SYN_IE(Error) )
-import Id ( idType, GenId, SYN_IE(IdEnv), nullIdEnv )
-import Maybes ( catMaybes )
-import Name ( Name, isLocallyDefined, pprModule )
-import Pretty
-import TyCon ( TyCon, isSynTyCon )
-import Type ( applyTyCon, mkSynTy )
-import PprType ( GenType, GenTyVar )
+import Bag ( isEmptyBag )
+import ErrUtils ( WarnMsg, ErrMsg,
+ pprBagOfErrors, dumpIfSet, ghcExit
+ )
+import Id ( idType, GenId, IdEnv, nullIdEnv )
+import Maybes ( catMaybes, MaybeErr(..) )
+import Name ( Name, isLocallyDefined, pprModule, NamedThing(..) )
+import TyCon ( TyCon, isSynTyCon, tyConKind )
+import Class ( Class, classSelIds, classTyCon )
+import Type ( mkTyConApp, mkSynTy, Type )
+import TyVar ( emptyTyVarEnv )
import TysWiredIn ( unitTy )
import PrelMods ( gHC_MAIN, mAIN )
-import PrelInfo ( main_NAME, mainPrimIO_NAME, ioTyCon_NAME, primIoTyCon_NAME )
-import TyVar ( GenTyVar, SYN_IE(TyVarEnv), nullTyVarEnv )
+import PrelInfo ( main_NAME, ioTyCon_NAME )
import Unify ( unifyTauTy )
import UniqFM ( lookupUFM_Directly, lookupWithDefaultUFM_Directly,
filterUFM, eltsUFM )
import Unique ( Unique )
+import UniqSupply ( UniqSupply )
import Util
import Bag ( Bag, isEmptyBag )
-
import FiniteMap ( emptyFM, FiniteMap )
-tycon_specs = emptyFM
+import Outputable
\end{code}
Outside-world interface:
\begin{code}
+
-- Convenient type synonyms first:
type TcResults
- = (TcResultBinds,
- [TyCon],
+ = (TypecheckedMonoBinds,
+ [TyCon], [Class],
Bag InstInfo, -- Instance declaration information
- TcSpecialiseRequests,
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 TcSpecialiseRequests
- = FiniteMap TyCon [(Bool, [Maybe Type])]
- -- source tycon specialisation requests
-
-type TcDDumpDeriv
- = PprStyle -> Pretty
+type TcDDumpDeriv = SDoc
---------------
typecheckModule
:: UniqSupply
-> RnNameSupply
-> RenamedHsModule
- -> MaybeErr
- (TcResults, -- if all goes well...
- Bag Warning) -- (we can still get warnings)
- (Bag Error, -- if we had errors...
- Bag Warning)
+ -> IO (Maybe TcResults)
typecheckModule us rn_name_supply mod
- = initTc us (tcModule rn_name_supply mod)
+ = let
+ (maybe_result, warns, errs) = initTc us (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:
(HsModule mod_name verion exports imports fixities decls src_loc)
= 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].
+ --
+ -- 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
+ ] $
- -- trace "tc1" $
-
- fixTc (\ ~(_, _, _, _, _, _, sig_ids) ->
-
- -- trace "tc2" $
- tcExtendGlobalValEnv sig_ids (
-
- -- The knot for instance information. This isn't used at all
- -- till we type-check value declarations
- fixTc ( \ ~(rec_inst_mapper, _, _, _, _) ->
+ -- Interface type signatures
+ -- We tie a knot so that the Ids read out of interfaces are in scope
+ -- when we read their pragmas.
+ -- 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 unf_env decls `thenTc` \ sig_ids ->
+ tcExtendGlobalValEnv sig_ids $
- -- Type-check the type and class decls
- -- trace "tcTyAndClassDecls:" $
- tcTyAndClassDecls1 rec_inst_mapper decls `thenTc` \ env ->
- -- trace "tc3" $
- -- Typecheck the instance decls, includes deriving
- tcSetEnv env (
- -- trace "tcInstDecls:" $
- tcInstDecls1 decls mod_name rn_name_supply
- ) `thenTc` \ (inst_info, deriv_binds, ddump_deriv) ->
+ -- Value declarations next.
+ -- We also typecheck any extra binds that came out of the "deriving" process
+ -- 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 $
- -- trace "tc4" $
- buildInstanceEnvs inst_info `thenTc` \ inst_mapper ->
- returnTc (inst_mapper, env, inst_info, deriv_binds, ddump_deriv)
+ -- 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) ->
- ) `thenTc` \ (_, env, inst_info, deriv_binds, ddump_deriv) ->
- -- trace "tc5" $
- tcSetEnv env (
- -- Default declarations
- tcDefaults decls `thenTc` \ defaulting_tys ->
- tcSetDefaultTys defaulting_tys ( -- for the iface sigs...
+ -- Check that "main" has the right signature
+ tcCheckMainSig mod_name `thenTc_`
- -- Create any necessary record selector Ids and their bindings
- -- "Necessary" includes data and newtype declarations
+ -- 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
- tycons = getEnv_TyCons env
- classes = getEnv_Classes env
+ lie_alldecls = lie_valdecls `plusLIE` lie_instdecls `plusLIE` lie_clasdecls
in
- mkDataBinds tycons `thenTc` \ (data_ids, data_binds) ->
-
- -- Extend the global value environment with
- -- a) constructors
- -- b) record selectors
- -- c) class op selectors
- tcExtendGlobalValEnv data_ids $
- tcExtendGlobalValEnv (concat (map classSelIds classes)) $
-
- -- Interface type signatures
- -- We tie a knot so that the Ids read out of interfaces are in scope
- -- when we read their pragmas.
- -- 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 decls `thenTc` \ sig_ids ->
- tcGetEnv `thenNF_Tc` \ env ->
- -- trace "tc6" $
-
- returnTc (env, inst_info, data_binds, deriv_binds, ddump_deriv, defaulting_tys, sig_ids)
+ tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
- )))) `thenTc` \ (env, inst_info, data_binds, deriv_binds, ddump_deriv, defaulting_tys, _) ->
- -- trace "tc7" $
- 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))
- (get_val_decls decls `ThenBinds` deriv_binds)
- ( -- Second pass over 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) ->
- tcCheckMainSig mod_name `thenTc_`
- 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, _) ->
-
- -- 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" $
- tcSimplifyTop lie_alldecls `thenTc` \ const_insts ->
-
-
- -- 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.
- --
- -- More horrible still, we have to do it in a careful order, so that
- -- all the TcIds are in scope when we come across them.
- --
- -- These bindings ought really to be bundled together in a huge
- -- recursive group, but HsSyn doesn't have recursion among Binds, only
- -- among MonoBinds. Sigh again.
- zonkDictBinds nullTyVarEnv nullIdEnv const_insts `thenNF_Tc` \ (const_insts', ve1) ->
- zonkBinds nullTyVarEnv ve1 val_binds `thenNF_Tc` \ (val_binds', ve2) ->
-
- zonkBinds nullTyVarEnv ve2 data_binds `thenNF_Tc` \ (data_binds', _) ->
- zonkBinds nullTyVarEnv ve2 inst_binds `thenNF_Tc` \ (inst_binds', _) ->
- zonkBinds nullTyVarEnv ve2 cls_binds `thenNF_Tc` \ (cls_binds', _) ->
-
- 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
- in
- -- FINISHED AT LAST
- returnTc (
- (data_binds', cls_binds', inst_binds', val_binds', const_insts'),
+ -- 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) ->
- local_tycons, inst_info, tycon_specs,
+ returnTc (really_final_env,
+ (all_binds', local_tycons, local_classes, inst_info, ddump_deriv))
- 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}
\begin{code}
tcCheckMainSig mod_name
- | not is_main && not is_ghc_main
+ | mod_name /= mAIN
= returnTc () -- A non-main module
| otherwise
= -- Check that main is defined
- tcLookupTyCon tycon_name `thenTc` \ (_,_,tycon) ->
- tcLookupLocalValue main_name `thenNF_Tc` \ maybe_main_id ->
+ tcLookupTyCon ioTyCon_NAME `thenTc` \ (_,_,ioTyCon) ->
+ tcLookupLocalValue main_NAME `thenNF_Tc` \ maybe_main_id ->
case maybe_main_id of {
- Nothing -> failTc (noMainErr mod_name main_name);
+ Nothing -> failWithTc noMainErr ;
Just main_id ->
-- Check that it has the right type (or a more general one)
- let
- expected_ty | isSynTyCon tycon = mkSynTy tycon [unitTy]
- | otherwise = applyTyCon tycon [unitTy]
- -- This is bizarre. There ought to be a suitable function in Type.lhs!
+ let
+ expected_ty = mkTyConApp ioTyCon [unitTy]
in
- tcInstType [] expected_ty `thenNF_Tc` \ expected_tau ->
- tcId main_name `thenNF_Tc` \ (_, lie, main_tau) ->
- tcSetErrCtxt (mainTyCheckCtxt main_name) $
+ 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 main_name expected_ty (idType main_id))
+ main_tau `thenTc_`
+ checkTc (isEmptyBag lie) (mainTyMisMatch expected_ty (idType main_id))
}
- where
- is_main = mod_name == mAIN
- is_ghc_main = mod_name == gHC_MAIN
-
- main_name | is_main = main_NAME
- | otherwise = mainPrimIO_NAME
- tycon_name | is_main = ioTyCon_NAME
- | otherwise = primIoTyCon_NAME
-mainTyCheckCtxt main_name sty
- = ppCat [ppStr "When checking that", ppr sty main_name, ppStr "has the required type"]
+mainTyCheckCtxt
+ = hsep [ptext SLIT("When checking that"), ppr main_NAME, ptext SLIT("has the required type")]
-noMainErr mod_name main_name sty
- = ppCat [ppStr "Module", pprModule sty mod_name,
- ppStr "must include a definition for", ppr sty main_name]
+noMainErr
+ = hsep [ptext SLIT("Module"), quotes (pprModule mAIN),
+ ptext SLIT("must include a definition for"), quotes (ppr main_NAME)]
-mainTyMisMatch :: Name -> Type -> TcType s -> Error
-mainTyMisMatch main_name expected actual sty
- = ppHang (ppCat [ppr sty main_name, ppStr "has the wrong type"])
- 4 (ppAboves [
- ppCat [ppStr "Expected:", ppr sty expected],
- ppCat [ppStr "Inferred:", ppr sty actual]
+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}