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 )
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 )
26 import TcDefaults ( tcDefaults )
27 import TcEnv ( tcExtendGlobalValEnv, tcExtendTypeEnv,
28 getEnvTyCons, getEnvClasses, tcLookupValueMaybe,
29 explicitLookupValueByKey, tcSetValueEnv,
30 tcLookupTyCon, initEnv,
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 ( mkDataBinds )
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 Name ( Name, nameUnique, isLocallyDefined, NamedThing(..) )
53 import TyCon ( TyCon, tyConKind )
54 import DataCon ( dataConId )
55 import Class ( Class, classSelIds, classTyCon )
56 import Type ( mkTyConApp, mkForAllTy,
57 boxedTypeKind, getTyVar, Type )
58 import TysWiredIn ( unitTy )
59 import PrelMods ( mAIN_Name )
60 import PrelInfo ( main_NAME, thinAirIdNames, setThinAirIds )
61 import TcUnify ( unifyTauTy )
62 import Unique ( Unique )
63 import UniqSupply ( UniqSupply )
64 import Maybes ( maybeToBool )
66 import Bag ( Bag, isEmptyBag )
72 Outside-world interface:
75 -- Convenient type synonyms first:
78 tc_binds :: TypecheckedMonoBinds,
80 tc_classes :: [Class],
81 tc_insts :: Bag InstInfo, -- Instance declaration information
82 tc_fords :: [TypecheckedForeignDecl], -- Foreign import & exports.
83 tc_rules :: [TypecheckedRuleDecl], -- Transformation rules
85 tc_thinair :: [Id] -- The thin-air Ids
94 -> IO (Maybe TcResults)
96 typecheckModule us rn_name_supply iface_det mod
97 = initTc us initEnv (tcModule rn_name_supply (getIfaceFixities iface_det) mod)
98 >>= \ (maybe_result, warns, errs) ->
100 printErrorsAndWarnings errs warns >>
102 -- write the thin-air Id map
103 (case maybe_result of
104 Just results -> setThinAirIds (tc_thinair results)
108 dumpIfSet opt_D_dump_tc "Typechecked"
109 (case maybe_result of
110 Just results -> ppr (tc_binds results)
112 pp_rules (tc_rules results)
113 Nothing -> text "Typecheck failed") >>
115 return (if isEmptyBag errs then
121 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
122 nest 4 (vcat (map ppr rs)),
126 The internal monster:
128 tcModule :: RnNameSupply -- for renaming derivings
129 -> Fixities -- needed for Show/Read derivings.
130 -> RenamedHsModule -- input
131 -> TcM s TcResults -- output
133 tcModule rn_name_supply fixities
134 (HsModule mod_name verion exports imports decls src_loc)
135 = tcAddSrcLoc src_loc $ -- record where we're starting
137 fixTc (\ ~(unf_env ,_) ->
138 -- unf_env is used for type-checking interface pragmas
139 -- which is done lazily [ie failure just drops the pragma
140 -- without having any global-failure effect].
142 -- unf_env is also used to get the pragam info
143 -- for imported dfuns and default methods
145 -- The knot for instance information. This isn't used at all
146 -- till we type-check value declarations
147 fixTc ( \ ~(rec_inst_mapper, _, _, _) ->
149 -- Type-check the type and class decls
150 tcTyAndClassDecls unf_env rec_inst_mapper decls `thenTc` \ env ->
152 -- Typecheck the instance decls, includes deriving
154 tcInstDecls1 unf_env decls mod_name fixities rn_name_supply
155 ) `thenTc` \ (inst_info, deriv_binds) ->
157 buildInstanceEnvs inst_info `thenNF_Tc` \ inst_mapper ->
159 returnTc (inst_mapper, env, inst_info, deriv_binds)
161 -- End of inner fix loop
162 ) `thenTc` \ (_, env, inst_info, deriv_binds) ->
166 -- Default declarations
167 tcDefaults decls `thenTc` \ defaulting_tys ->
168 tcSetDefaultTys defaulting_tys $
170 -- Create any necessary record selector Ids and their bindings
171 -- "Necessary" includes data and newtype declarations
172 -- We don't create bindings for dictionary constructors;
173 -- they are always fully applied, and the bindings are just there
174 -- to support partial applications
176 tycons = getEnvTyCons env
177 classes = getEnvClasses env
178 local_tycons = filter isLocallyDefined tycons
179 local_classes = filter isLocallyDefined classes
181 mkDataBinds tycons `thenTc` \ (data_ids, data_binds) ->
183 -- Extend the global value environment with
185 -- (b) record selectors
186 -- (c) class op selectors
187 -- (d) default-method ids... where? I can't see where these are
188 -- put into the envt, and I'm worried that the zonking phase
189 -- will find they aren't there and complain.
190 tcExtendGlobalValEnv data_ids $
191 tcExtendGlobalValEnv (concat (map classSelIds classes)) $
193 -- Extend the TyCon envt with the tycons corresponding to
194 -- the classes, and the global value environment with the
195 -- corresponding data cons.
196 -- They are mentioned in types in interface files.
197 tcExtendGlobalValEnv (map (dataConId . classDataCon) classes) $
198 tcExtendTypeEnv [ (getName tycon, (kindToTcKind (tyConKind tycon), Nothing, ATyCon tycon))
200 let tycon = classTyCon clas
203 -- Interface type signatures
204 -- We tie a knot so that the Ids read out of interfaces are in scope
205 -- when we read their pragmas.
206 -- What we rely on is that pragmas are typechecked lazily; if
207 -- any type errors are found (ie there's an inconsistency)
208 -- we silently discard the pragma
209 tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
210 tcExtendGlobalValEnv sig_ids $
212 -- foreign import declarations next.
213 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
214 tcExtendGlobalValEnv fo_ids $
216 -- Value declarations next.
217 -- We also typecheck any extra binds that came out of the "deriving" process
219 (\ is_rec binds1 (binds2, thing) -> (binds1 `AndMonoBinds` binds2, thing))
220 (get_val_decls decls `ThenBinds` deriv_binds)
221 ( tcGetEnv `thenNF_Tc` \ env ->
222 tcGetUnique `thenNF_Tc` \ uniq ->
223 returnTc ((EmptyMonoBinds, env), emptyLIE)
224 ) `thenTc` \ ((val_binds, final_env), lie_valdecls) ->
227 -- foreign export declarations next.
228 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
230 -- Second pass over class and instance declarations,
231 -- to compile the bindings themselves.
232 tcInstDecls2 inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
233 tcClassDecls2 decls `thenNF_Tc` \ (lie_clasdecls, cls_binds) ->
234 tcRules decls `thenNF_Tc` \ (lie_rules, rules) ->
237 -- Deal with constant or ambiguous InstIds. How could
238 -- there be ambiguous ones? They can only arise if a
239 -- top-level decl falls under the monomorphism
240 -- restriction, and no subsequent decl instantiates its
241 -- type. (Usually, ambiguous type variables are resolved
242 -- during the generalisation step.)
244 lie_alldecls = lie_valdecls `plusLIE`
245 lie_instdecls `plusLIE`
246 lie_clasdecls `plusLIE`
247 lie_fodecls `plusLIE`
250 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
252 -- Check that Main defines main
253 (if mod_name == mAIN_Name then
254 tcLookupValueMaybe main_NAME `thenNF_Tc` \ maybe_main ->
255 checkTc (maybeToBool maybe_main) noMainErr
260 -- Backsubstitution. This must be done last.
261 -- Even tcSimplifyTop may do some unification.
263 all_binds = data_binds `AndMonoBinds`
264 val_binds `AndMonoBinds`
265 inst_binds `AndMonoBinds`
266 cls_binds `AndMonoBinds`
267 const_inst_binds `AndMonoBinds`
270 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', really_final_env) ->
271 tcSetValueEnv really_final_env $
272 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
273 zonkRules rules `thenNF_Tc` \ rules' ->
276 thin_air_ids = map (explicitLookupValueByKey really_final_env . nameUnique) thinAirIdNames
277 -- When looking up the thin-air names we must use
278 -- a global env that includes the zonked locally-defined Ids too
279 -- Hence using really_final_env
281 returnTc (really_final_env,
282 (TcResults { tc_binds = all_binds',
283 tc_tycons = local_tycons,
284 tc_classes = local_classes,
285 tc_insts = inst_info,
286 tc_fords = foi_decls ++ foe_decls',
288 tc_env = really_final_env,
289 tc_thinair = thin_air_ids
293 -- End of outer fix loop
294 ) `thenTc` \ (final_env, stuff) ->
297 get_val_decls decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
303 = hsep [ptext SLIT("Module"), quotes (pprModuleName mAIN_Name),
304 ptext SLIT("must include a definition for"), quotes (ppr main_NAME)]