2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
12 #include "HsVersions.h"
14 import CmdLineOpts ( opt_D_dump_tc, opt_D_dump_types, opt_PprStyle_Debug )
15 import HsSyn ( HsModule(..), HsBinds(..), MonoBinds(..), HsDecl(..) )
16 import RnHsSyn ( RenamedHsModule )
17 import TcHsSyn ( TcMonoBinds, TypecheckedMonoBinds,
18 TypecheckedForeignDecl, TypecheckedRuleDecl,
19 zonkTopBinds, zonkForeignExports, zonkRules
23 import Inst ( Inst, emptyLIE, plusLIE )
24 import TcBinds ( tcTopBindsAndThen )
25 import TcClassDcl ( tcClassDecls2, mkImplicitClassBinds )
26 import TcDefaults ( tcDefaults )
27 import TcEnv ( tcExtendGlobalValEnv, tcExtendTypeEnv,
28 getEnvTyCons, getEnvClasses, tcLookupValueMaybe,
29 explicitLookupValueByKey, tcSetValueEnv,
30 tcLookupTyCon, initEnv, valueEnvIds,
31 ValueEnv, TcTyThing(..)
33 import TcExpr ( tcId )
34 import TcRules ( tcRules )
35 import TcForeign ( tcForeignImports, tcForeignExports )
36 import TcIfaceSig ( tcInterfaceSigs )
37 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
38 import TcInstUtil ( buildInstanceEnvs, classDataCon, InstInfo )
39 import TcSimplify ( tcSimplifyTop )
40 import TcTyClsDecls ( tcTyAndClassDecls )
41 import TcTyDecls ( mkImplicitDataBinds )
42 import TcType ( TcType, typeToTcType,
47 import RnMonad ( RnNameSupply, getIfaceFixities, Fixities, InterfaceDetails )
48 import Bag ( isEmptyBag )
49 import ErrUtils ( Message, printErrorsAndWarnings, dumpIfSet )
50 import Id ( Id, idType )
51 import Module ( pprModuleName )
52 import OccName ( isSysOcc )
53 import Name ( Name, nameUnique, nameOccName, isLocallyDefined,
54 toRdrName, NamedThing(..)
56 import TyCon ( TyCon, tyConKind )
57 import Class ( Class, classSelIds, classTyCon )
58 import Type ( mkTyConApp, mkForAllTy,
59 boxedTypeKind, getTyVar, Type )
60 import TysWiredIn ( unitTy )
61 import PrelMods ( mAIN_Name )
62 import PrelInfo ( main_NAME, thinAirIdNames, setThinAirIds )
63 import TcUnify ( unifyTauTy )
64 import Unique ( Unique )
65 import UniqSupply ( UniqSupply )
66 import Maybes ( maybeToBool )
68 import Bag ( Bag, isEmptyBag )
74 Outside-world interface:
77 -- Convenient type synonyms first:
80 tc_binds :: TypecheckedMonoBinds,
82 tc_classes :: [Class],
83 tc_insts :: Bag InstInfo, -- Instance declaration information
84 tc_fords :: [TypecheckedForeignDecl], -- Foreign import & exports.
85 tc_rules :: [TypecheckedRuleDecl], -- Transformation rules
87 tc_thinair :: [Id] -- The thin-air Ids
96 -> IO (Maybe TcResults)
98 typecheckModule us rn_name_supply iface_det mod
99 = initTc us initEnv (tcModule rn_name_supply (getIfaceFixities iface_det) mod)
100 >>= \ (maybe_result, warns, errs) ->
102 printErrorsAndWarnings errs warns >>
104 -- write the thin-air Id map
105 (case maybe_result of
106 Just results -> setThinAirIds (tc_thinair results)
110 (case maybe_result of
112 Just results -> dumpIfSet opt_D_dump_tc "Typechecked" (dump_tc results)
115 return (if isEmptyBag errs then
121 = ppr (tc_binds results) $$ pp_rules (tc_rules results)
124 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
125 nest 4 (vcat (map ppr rs)),
129 The internal monster:
131 tcModule :: RnNameSupply -- for renaming derivings
132 -> Fixities -- needed for Show/Read derivings.
133 -> RenamedHsModule -- input
134 -> TcM s TcResults -- output
136 tcModule rn_name_supply fixities
137 (HsModule mod_name verion exports imports decls _ src_loc)
138 = tcAddSrcLoc src_loc $ -- record where we're starting
140 fixTc (\ ~(unf_env ,_) ->
141 -- unf_env is used for type-checking interface pragmas
142 -- which is done lazily [ie failure just drops the pragma
143 -- without having any global-failure effect].
145 -- unf_env is also used to get the pragam info
146 -- for imported dfuns and default methods
148 -- The knot for instance information. This isn't used at all
149 -- till we type-check value declarations
150 fixTc ( \ ~(rec_inst_mapper, _, _, _) ->
152 -- Type-check the type and class decls
153 tcTyAndClassDecls unf_env rec_inst_mapper decls `thenTc` \ env ->
155 -- Typecheck the instance decls, includes deriving
157 tcInstDecls1 unf_env decls mod_name fixities rn_name_supply
158 ) `thenTc` \ (inst_info, deriv_binds) ->
160 buildInstanceEnvs inst_info `thenNF_Tc` \ inst_mapper ->
162 returnTc (inst_mapper, env, inst_info, deriv_binds)
164 -- End of inner fix loop
165 ) `thenTc` \ (_, env, inst_info, deriv_binds) ->
169 -- Default declarations
170 tcDefaults decls `thenTc` \ defaulting_tys ->
171 tcSetDefaultTys defaulting_tys $
173 -- Create any necessary record selector Ids and their bindings
174 -- "Necessary" includes data and newtype declarations
175 -- We don't create bindings for dictionary constructors;
176 -- they are always fully applied, and the bindings are just there
177 -- to support partial applications
179 tycons = getEnvTyCons env
180 classes = getEnvClasses env
181 local_tycons = filter isLocallyDefined tycons
182 local_classes = filter isLocallyDefined classes
184 mkImplicitDataBinds tycons `thenTc` \ (data_ids, imp_data_binds) ->
185 mkImplicitClassBinds classes `thenNF_Tc` \ (cls_ids, imp_cls_binds) ->
187 -- Extend the global value environment with
189 -- (b) record selectors
190 -- (c) class op selectors
191 -- (d) default-method ids... where? I can't see where these are
192 -- put into the envt, and I'm worried that the zonking phase
193 -- will find they aren't there and complain.
194 tcExtendGlobalValEnv data_ids $
195 tcExtendGlobalValEnv cls_ids $
197 -- Extend the TyCon envt with the tycons corresponding to
199 -- They are mentioned in types in interface files.
200 tcExtendTypeEnv [ (getName tycon, (kindToTcKind (tyConKind tycon), Nothing, ATyCon tycon))
202 let tycon = classTyCon clas
205 -- Interface type signatures
206 -- We tie a knot so that the Ids read out of interfaces are in scope
207 -- when we read their pragmas.
208 -- What we rely on is that pragmas are typechecked lazily; if
209 -- any type errors are found (ie there's an inconsistency)
210 -- we silently discard the pragma
211 tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
212 tcExtendGlobalValEnv sig_ids $
214 -- foreign import declarations next.
215 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
216 tcExtendGlobalValEnv fo_ids $
218 -- Value declarations next.
219 -- We also typecheck any extra binds that came out of the "deriving" process
221 (\ is_rec binds1 (binds2, thing) -> (binds1 `AndMonoBinds` binds2, thing))
222 (get_val_decls decls `ThenBinds` deriv_binds)
223 ( tcGetEnv `thenNF_Tc` \ env ->
224 tcGetUnique `thenNF_Tc` \ uniq ->
225 returnTc ((EmptyMonoBinds, env), emptyLIE)
226 ) `thenTc` \ ((val_binds, final_env), lie_valdecls) ->
229 -- foreign export declarations next.
230 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
232 -- Second pass over class and instance declarations,
233 -- to compile the bindings themselves.
234 tcInstDecls2 inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
235 tcClassDecls2 decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
236 tcRules decls `thenNF_Tc` \ (lie_rules, rules) ->
239 -- Deal with constant or ambiguous InstIds. How could
240 -- there be ambiguous ones? They can only arise if a
241 -- top-level decl falls under the monomorphism
242 -- restriction, and no subsequent decl instantiates its
243 -- type. (Usually, ambiguous type variables are resolved
244 -- during the generalisation step.)
246 lie_alldecls = lie_valdecls `plusLIE`
247 lie_instdecls `plusLIE`
248 lie_clasdecls `plusLIE`
249 lie_fodecls `plusLIE`
252 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
254 -- Check that Main defines main
255 (if mod_name == mAIN_Name then
256 tcLookupValueMaybe main_NAME `thenNF_Tc` \ maybe_main ->
257 checkTc (maybeToBool maybe_main) noMainErr
262 -- Backsubstitution. This must be done last.
263 -- Even tcSimplifyTop may do some unification.
265 all_binds = imp_data_binds `AndMonoBinds`
266 imp_cls_binds `AndMonoBinds`
267 val_binds `AndMonoBinds`
268 inst_binds `AndMonoBinds`
269 cls_dm_binds `AndMonoBinds`
270 const_inst_binds `AndMonoBinds`
273 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', really_final_env) ->
274 tcSetValueEnv really_final_env $
275 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
276 zonkRules rules `thenNF_Tc` \ rules' ->
279 thin_air_ids = map (explicitLookupValueByKey really_final_env . nameUnique) thinAirIdNames
280 -- When looking up the thin-air names we must use
281 -- a global env that includes the zonked locally-defined Ids too
282 -- Hence using really_final_env
284 returnTc (really_final_env,
285 (TcResults { tc_binds = all_binds',
286 tc_tycons = local_tycons,
287 tc_classes = local_classes,
288 tc_insts = inst_info,
289 tc_fords = foi_decls ++ foe_decls',
291 tc_env = really_final_env,
292 tc_thinair = thin_air_ids
296 -- End of outer fix loop
297 ) `thenTc` \ (final_env, stuff) ->
300 get_val_decls decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
306 = hsep [ptext SLIT("Module"), quotes (pprModuleName mAIN_Name),
307 ptext SLIT("must include a definition for"), quotes (ppr main_NAME)]