%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
%
\section[TcModule]{Typechecking a whole module}
\begin{code}
-#include "HsVersions.h"
-
module TcModule (
- tcModule,
-
- -- to make the interface self-sufficient...
- Module, Bag, CE(..), E, Binds, FixityDecl, Expr, InPat,
- RenamedPat(..), TypecheckedPat, Id, Inst, Maybe, TcResult,
- Name, ProtoName, SrcLoc, Subst, TCE(..), UniqFM,
- Error(..), Pretty(..), PprStyle, PrettyRep, InstInfo
+ typecheckModule,
+ TcResults,
+ TcDDumpDeriv
) where
-import TcMonad -- typechecking monad machinery
-import AbsSyn -- the stuff being typechecked
-
--- OLD:
---import AbsPrel ( stringTy,
--- eqStringId, neStringId, ltStringId,
--- leStringId, geStringId, gtStringId,
--- maxStringId, minStringId, tagCmpStringId,
--- dfunEqStringId, dfunOrdStringId,
--- pRELUDE_CORE
--- IF_ATTACK_PRAGMAS(COMMA mkListTy COMMA charTy)
--- )
---#if USE_ATTACK_PRAGMAS
---import PrelVals ( string_cmp_id ) -- shouldn't even be visible, really
---#endif
-import BackSubst ( applyTcSubstToBinds )
-import Bag ( unionBags, bagToList, emptyBag, listToBag )
-import CE ( nullCE, checkClassCycles, lookupCE, CE(..) )
-import CmdLineOpts ( GlobalSwitch(..) )
-import E
-import HsCore -- ****** NEED TO SEE CONSTRUCTORS ******
-import HsPragmas -- ****** NEED TO SEE CONSTRUCTORS ******
-import InstEnv
-import LIE ( unMkLIE, plusLIE, LIE )
-import Name ( Name(..) )
-import RenameAuxFuns ( GlobalNameFuns(..), GlobalNameFun(..), ProtoName, Maybe )
-import SrcLoc ( mkBuiltinSrcLoc, SrcLoc )
-import TCE ( checkTypeCycles, TCE(..), UniqFM )
+#include "HsVersions.h"
+
+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, emptyLIE, plusLIE )
import TcBinds ( tcTopBindsAndThen )
-import TcClassDcl ( tcClassDecls1, tcClassDecls2, ClassInfo )
+import TcClassDcl ( tcClassDecls2 )
import TcDefaults ( tcDefaults )
-import TcDeriv ( tcDeriving )
+import TcEnv ( TcIdOcc(..), tcExtendGlobalValEnv, tcExtendTyConEnv, getEnv_LocalIds,
+ getEnv_TyCons, getEnv_Classes, tcLookupLocalValue,
+ tcLookupLocalValueByKey, tcLookupTyCon,
+ tcLookupGlobalValueByKeyMaybe )
+import TcExpr ( tcId )
import TcIfaceSig ( tcInterfaceSigs )
-import TcInstDcls ( tcInstDecls1, tcInstDecls2, tcSpecInstSigs, buildInstanceEnvs, InstInfo(..) )
+import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
+import TcInstUtil ( buildInstanceEnvs, classDataCon, InstInfo )
import TcSimplify ( tcSimplifyTop )
-import TcTyDecls ( tcTyDecls )
-import Unique -- some ClassKey stuff
-import UniqFM ( emptyUFM ) -- profiling, pragmas only
+import TcTyClsDecls ( tcTyAndClassDecls1 )
+import TcTyDecls ( mkDataBinds )
+import TcType ( TcType, tcInstType )
+import TcKind ( TcKind, kindToTcKind )
+
+import RnMonad ( RnNameSupply(..) )
+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, ioTyCon_NAME )
+import Unify ( unifyTauTy )
+import UniqFM ( lookupUFM_Directly, lookupWithDefaultUFM_Directly,
+ filterUFM, eltsUFM )
+import Unique ( Unique )
+import UniqSupply ( UniqSupply )
import Util
-
-import Pretty -- Debugging
+import Bag ( Bag, isEmptyBag )
+import FiniteMap ( emptyFM, FiniteMap )
+import Outputable
\end{code}
+Outside-world interface:
\begin{code}
-tcModule :: E -- initial typechecker environment
- -> GlobalNameFuns -- final renamer info (to do derivings)
- -> RenamedModule -- input
- -> TcM ((TypecheckedBinds, -- binds from class decls; does NOT
- -- include default-methods bindings
- TypecheckedBinds, -- binds from instance decls; INCLUDES
- -- class default-methods binds
- TypecheckedBinds, -- binds from value decls
- [(Inst, TypecheckedExpr)]),
-
- ([RenamedFixityDecl], -- things for the interface generator
- [Id], -- to look at...
- CE,
- TCE,
- Bag InstInfo),
-
- FiniteMap TyCon [(Bool, [Maybe UniType])],
- -- source tycon specialisation requests
-
---UNUSED: E, -- environment of total accumulated info
- E, -- environment of info due to this module only
- PprStyle -> Pretty) -- -ddump-deriving info (passed upwards)
-
-tcModule e1 renamer_name_funs
- (Module mod_name exports imports_should_be_empty fixities
- tydecls ty_sigs classdecls instdecls specinst_sigs
- default_decls valdecls sigs src_loc)
-
- = addSrcLocTc 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
- -- without having any global-failure effect].
- fixTc (\ ~(rec_gve_sigs, _, _, _, _, _, _, _, _, _) ->
- let
- e2 = plusE_GVE e1 rec_gve_sigs
+-- Convenient type synonyms first:
+type TcResults
+ = (TypecheckedMonoBinds,
+ [TyCon], [Class],
+ Bag InstInfo, -- Instance declaration information
+ TcDDumpDeriv)
+
+type TcDDumpDeriv = SDoc
+
+---------------
+typecheckModule
+ :: UniqSupply
+ -> RnNameSupply
+ -> RenamedHsModule
+ -> IO (Maybe TcResults)
+
+typecheckModule us 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:
+\begin{code}
+tcModule :: RnNameSupply -- for renaming derivings
+ -> RenamedHsModule -- input
+ -> TcM s TcResults -- output
+
+tcModule rn_name_supply
+ (HsModule mod_name verion exports imports fixities decls src_loc)
+ = tcAddSrcLoc src_loc $ -- record where we're starting
+
+ 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
+ ] $
+
+ -- 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 $
- -- The knot for instance information. This isn't used at all
- -- till we type-check value declarations.
- fixTc ( \ ~(rec_inst_mapper, _, _, _, _, _, _, _, _) ->
-
- -- The knot for TyCons and Classes
- fixTc ( \ ~(_, rec_tce, rec_ce, rec_datacons_gve, rec_ops_gve, _, _) ->
- let
- e3 = e2
- `plusE_GVE` rec_datacons_gve
- `plusE_GVE` rec_ops_gve
- `plusE_TCE` rec_tce
- `plusE_CE` rec_ce
- in
- -- DO THE TYPE DECLS
- -- Including the pragmas: {-# ABSTRACT TypeSyn #-}
- -- {-# SPECIALIZE data DataType ... #-}
- let
- (absty_sigs, specdata_sigs) = partition is_absty_sig ty_sigs
- is_absty_sig (AbstractTypeSig _ _) = True
- is_absty_sig (SpecDataSig _ _ _) = False
-
- is_abs_syn :: Name -> Bool -- a lookup fn for abs synonyms
- is_abs_syn n
- = n `is_elem` [ tc | (AbstractTypeSig tc _) <- absty_sigs ]
- where
- is_elem = isIn "tcModule"
-
- get_spec_sigs :: Name -> [RenamedDataTypeSig]
- get_spec_sigs n
- = [ sig | sig@(SpecDataSig tc _ _) <- specdata_sigs, n == tc]
- in
- babyTcMtoTcM (tcTyDecls e3 is_abs_syn get_spec_sigs tydecls)
- `thenTc` \ (tce, datacons_gve, tycon_specs) ->
-
- -- DO THE CLASS DECLS
- tcClassDecls1 e3 rec_inst_mapper classdecls
- `thenTc` \ (class_info, ce, ops_gve) ->
-
- -- End of TyCon/Class knot
- -- Augment whatever TCE/GVE/CE stuff was in orig_e
- returnTc (e3, tce, ce, datacons_gve, ops_gve, class_info, tycon_specs)
-
- -- End of inner fixTc
- ) `thenTc` ( \ (e3, tce_here, ce_here, _, _, class_info, tycon_specs) ->
- -- The "here" things are the extra decls defined in this
- -- module or its imports; but not including whatever was
- -- in the incoming e.
-
- -- Grab completed tce/ce and check for type/class cycles
- -- The tce/ce are now stable and lookable-at, with the
- -- exception of the instance information inside classes
- let
- ce3 = getE_CE e3
- tce3 = getE_TCE e3
- in
- checkMaybeErrTc (checkTypeCycles tce3) id `thenTc_`
- checkMaybeErrTc (checkClassCycles ce3) id `thenTc_`
-
- -- Now instance declarations
- tcInstDecls1 e3 ce3 tce3 instdecls `thenNF_Tc` \ decl_inst_info ->
-
- -- Handle "derived" instances; note that we only do derivings
- -- for things in this module; we ignore deriving decls from
- -- interfaces! We pass fixities, because they may be used in
- -- doing Text.
-
- tcDeriving mod_name renamer_name_funs decl_inst_info tce3 fixities
- `thenTc` \ (deriv_inst_info, extra_deriv_binds, ddump_deriv) ->
-
- let
- inst_info = deriv_inst_info `unionBags` decl_inst_info
- in
- -- Handle specialise instance pragmas
- getSwitchCheckerTc `thenNF_Tc` \ sw_chkr ->
- (if sw_chkr SpecialiseOverloaded then
- tcSpecInstSigs e3 ce3 tce3 inst_info specinst_sigs
- else
- returnTc emptyBag)
- `thenTc` \ spec_inst_info ->
- let
- full_inst_info = inst_info `unionBags` spec_inst_info
- in
- -- OK, now do the inst-mapper stuff
- buildInstanceEnvs full_inst_info `thenTc` \ all_insts_mapper ->
-
- returnTc (all_insts_mapper, e3, ce_here, tce_here, class_info, tycon_specs,
- full_inst_info, extra_deriv_binds, ddump_deriv)
-
- -- End of outer fixTc
- )) `thenTc` ( \ (_, e3, ce_here, tce_here, class_info, tycon_specs,
- full_inst_info, extra_deriv_binds, ddump_deriv) ->
-
- -- Default declarations
- tcDefaults e3 default_decls `thenTc` \ defaulting_tys ->
- setDefaultingTys defaulting_tys ( -- for the iface sigs...
-
- -- 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
-
- babyTcMtoTcM (tcInterfaceSigs e3 sigs) `thenTc` \ gve_sigs ->
-
- returnTc (gve_sigs, e3, ce_here, tce_here, class_info, tycon_specs, defaulting_tys,
- full_inst_info, extra_deriv_binds, ddump_deriv)
-
- -- End of extremely outer fixTc
- ))) `thenTc` \ (_, e3, ce_here, tce_here, class_info, tycon_specs, defaulting_tys,
- full_inst_info, extra_deriv_binds, ddump_deriv) ->
-
- setDefaultingTys defaulting_tys ( -- to the end...
-- Value declarations next.
-- We also typecheck any extra binds that came out of the "deriving" process
- -- Nota bene
- tcTopBindsAndThen
- e3
- (\ binds1 (binds2, thing) -> (binds1 `ThenBinds` binds2, thing))
- (valdecls `ThenBinds` extra_deriv_binds)
- (\ e4 ->
- -- Second pass over instance declarations,
+ -- 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 $
+
+
+ -- Second pass over class and instance declarations,
-- to compile the bindings themselves.
- tcInstDecls2 e4 full_inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
- tcClassDecls2 e4 class_info `thenNF_Tc` \ (lie_clasdecls, class_binds) ->
- returnTc ( (EmptyBinds, (inst_binds, class_binds, e4)),
- lie_instdecls `plusLIE` lie_clasdecls,
- () )
- )
-
- `thenTc` \ ((val_binds, (inst_binds, class_binds, e4)), 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.)
-
- tcSimplifyTop (unMkLIE lie_alldecls) `thenTc` \ const_inst_binds ->
-
- -- 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.
-
- applyTcSubstToBinds val_binds `thenNF_Tc` \ val_binds' ->
- applyTcSubstToBinds inst_binds `thenNF_Tc` \ inst_binds' ->
- applyTcSubstToBinds class_binds `thenNF_Tc` \ class_binds' ->
-
- -- ToDo: probably need to back-substitute over all
- -- stuff in 'e4'; we do so here over the Ids,
- -- which is probably enough. WDP 95/06
- mapNF_Tc applyTcSubstToId (getE_GlobalVals e4)
- `thenNF_Tc` \ if_global_ids ->
-
- -- FINISHED AT LAST
- returnTc (
- (class_binds', inst_binds', val_binds', const_inst_binds),
-
- -- the next collection is just for mkInterface
- (fixities, if_global_ids, ce_here, tce_here, full_inst_info),
-
- tycon_specs,
-
---UNUSED: e4,
-
- -- and... TCE needed for code generation; rest needed for interpreter.
- -- ToDo: still wrong: needs isLocallyDeclared run over everything
- mkE tce_here {-gve_here lve-} ce_here,
- -- NB: interpreter would probably need the gve_here stuff
- ddump_deriv
- )))
+ -- 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}
+
+
+\begin{code}
+tcCheckMainSig mod_name
+ | mod_name /= mAIN
+ = returnTc () -- A non-main module
+
+ | otherwise
+ = -- 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}