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 HsTypes ( toHsType )
17 import RnHsSyn ( RenamedHsModule )
18 import TcHsSyn ( TypecheckedMonoBinds,
19 TypecheckedForeignDecl, TypecheckedRuleDecl,
20 zonkTopBinds, zonkForeignExports, zonkRules
24 import Inst ( emptyLIE, plusLIE )
25 import TcBinds ( tcTopBindsAndThen )
26 import TcClassDcl ( tcClassDecls2, mkImplicitClassBinds )
27 import TcDefaults ( tcDefaults )
28 import TcEnv ( tcExtendGlobalValEnv,
29 getEnvTyCons, getEnvClasses, tcLookupValueByKeyMaybe,
30 tcSetValueEnv, tcSetInstEnv, initEnv,
33 import TcRules ( tcRules )
34 import TcForeign ( tcForeignImports, tcForeignExports )
35 import TcIfaceSig ( tcInterfaceSigs )
36 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
37 import TcInstUtil ( buildInstanceEnv, InstInfo )
38 import TcSimplify ( tcSimplifyTop )
39 import TcTyClsDecls ( tcTyAndClassDecls )
40 import TcTyDecls ( mkImplicitDataBinds )
42 import RnMonad ( RnNameSupply, FixityEnv )
43 import Bag ( isEmptyBag )
44 import ErrUtils ( printErrorsAndWarnings, dumpIfSet )
45 import Id ( idType, idName )
46 import Module ( pprModuleName, mkThisModule )
47 import Name ( nameOccName, isLocallyDefined, isGlobalName,
48 toRdrName, nameEnvElts,
50 import OccName ( isSysOcc )
51 import TyCon ( TyCon, isClassTyCon )
52 import Class ( Class )
53 import PrelNames ( mAIN_Name, mainKey )
54 import UniqSupply ( UniqSupply )
55 import Maybes ( maybeToBool )
57 import Bag ( Bag, isEmptyBag )
61 Outside-world interface:
64 -- Convenient type synonyms first:
67 tc_binds :: TypecheckedMonoBinds,
69 tc_classes :: [Class],
70 tc_insts :: Bag InstInfo, -- Instance declaration information
71 tc_fords :: [TypecheckedForeignDecl], -- Foreign import & exports.
72 tc_rules :: [TypecheckedRuleDecl], -- Transformation rules
82 -> IO (Maybe TcResults)
84 typecheckModule us rn_name_supply fixity_env mod
85 = initTc us initEnv (tcModule rn_name_supply fixity_env mod) >>= \ (maybe_result, warns, errs) ->
87 printErrorsAndWarnings errs warns >>
91 Just results -> dumpIfSet opt_D_dump_types "Type signatures" (dump_sigs results) >>
92 dumpIfSet opt_D_dump_tc "Typechecked" (dump_tc results)
95 return (if isEmptyBag errs then
101 = ppr (tc_binds results) $$ pp_rules (tc_rules results)
103 dump_sigs results -- Print type signatures
104 = -- Convert to HsType so that we get source-language style printing
105 -- And sort by RdrName
106 vcat $ map ppr_sig $ sortLt lt_sig $
107 [(toRdrName id, toHsType (idType id)) | id <- nameEnvElts (tc_env results),
111 lt_sig (n1,_) (n2,_) = n1 < n2
112 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
114 want_sig id | opt_PprStyle_Debug = True
115 | otherwise = isLocallyDefined n &&
117 not (isSysOcc (nameOccName n))
122 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
123 nest 4 (vcat (map ppr rs)),
127 The internal monster:
129 tcModule :: RnNameSupply -- for renaming derivings
130 -> FixityEnv -- needed for Show/Read derivings.
131 -> RenamedHsModule -- input
132 -> TcM s TcResults -- output
134 tcModule rn_name_supply fixities
135 (HsModule mod_name _ _ _ decls _ src_loc)
136 = tcAddSrcLoc src_loc $ -- record where we're starting
138 fixTc (\ ~(unf_env ,_) ->
139 -- unf_env is used for type-checking interface pragmas
140 -- which is done lazily [ie failure just drops the pragma
141 -- without having any global-failure effect].
143 -- unf_env is also used to get the pragam info
144 -- for imported dfuns and default methods
146 -- Type-check the type and class decls
147 tcTyAndClassDecls unf_env decls `thenTc` \ env ->
149 -- Typecheck the instance decls, includes deriving
152 tcInstDecls1 unf_env decls
153 (mkThisModule mod_name)
154 fixities rn_name_supply `thenTc` \ (inst_info, deriv_binds) ->
156 buildInstanceEnv inst_info `thenNF_Tc` \ inst_env ->
158 tcSetInstEnv inst_env $
160 classes = getEnvClasses env
161 tycons = getEnvTyCons env -- INCLUDES tycons derived from classes
162 local_classes = filter isLocallyDefined classes
163 local_tycons = [ tc | tc <- tycons,
165 not (isClassTyCon tc)
167 -- For local_tycons, filter out the ones derived from classes
168 -- Otherwise the latter show up in interface files
171 -- Default declarations
172 tcDefaults decls `thenTc` \ defaulting_tys ->
173 tcSetDefaultTys defaulting_tys $
175 -- Interface type signatures
176 -- We tie a knot so that the Ids read out of interfaces are in scope
177 -- when we read their pragmas.
178 -- What we rely on is that pragmas are typechecked lazily; if
179 -- any type errors are found (ie there's an inconsistency)
180 -- we silently discard the pragma
181 -- We must do this before mkImplicitDataBinds (which comes next), since
182 -- the latter looks up unpackCStringId, for example, which is usually
184 tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
185 tcExtendGlobalValEnv sig_ids $
187 -- Create any necessary record selector Ids and their bindings
188 -- "Necessary" includes data and newtype declarations
189 -- We don't create bindings for dictionary constructors;
190 -- they are always fully applied, and the bindings are just there
191 -- to support partial applications
192 mkImplicitDataBinds tycons `thenTc` \ (data_ids, imp_data_binds) ->
193 mkImplicitClassBinds classes `thenNF_Tc` \ (cls_ids, imp_cls_binds) ->
195 -- Extend the global value environment with
197 -- (b) record selectors
198 -- (c) class op selectors
199 -- (d) default-method ids... where? I can't see where these are
200 -- put into the envt, and I'm worried that the zonking phase
201 -- will find they aren't there and complain.
202 tcExtendGlobalValEnv data_ids $
203 tcExtendGlobalValEnv cls_ids $
205 -- foreign import declarations next.
206 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
207 tcExtendGlobalValEnv fo_ids $
209 -- Value declarations next.
210 -- We also typecheck any extra binds that came out of the "deriving" process
212 (\ is_rec binds1 (binds2, thing) -> (binds1 `AndMonoBinds` binds2, thing))
213 (get_val_decls decls `ThenBinds` deriv_binds)
214 ( tcGetEnv `thenNF_Tc` \ env ->
215 tcGetUnique `thenNF_Tc` \ uniq ->
216 returnTc ((EmptyMonoBinds, env), emptyLIE)
217 ) `thenTc` \ ((val_binds, final_env), lie_valdecls) ->
220 -- foreign export declarations next.
221 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
223 -- Second pass over class and instance declarations,
224 -- to compile the bindings themselves.
225 tcInstDecls2 inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
226 tcClassDecls2 decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
227 tcRules decls `thenNF_Tc` \ (lie_rules, rules) ->
230 -- Deal with constant or ambiguous InstIds. How could
231 -- there be ambiguous ones? They can only arise if a
232 -- top-level decl falls under the monomorphism
233 -- restriction, and no subsequent decl instantiates its
234 -- type. (Usually, ambiguous type variables are resolved
235 -- during the generalisation step.)
237 lie_alldecls = lie_valdecls `plusLIE`
238 lie_instdecls `plusLIE`
239 lie_clasdecls `plusLIE`
240 lie_fodecls `plusLIE`
243 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
245 -- Check that Main defines main
246 (if mod_name == mAIN_Name then
247 tcLookupValueByKeyMaybe mainKey `thenNF_Tc` \ maybe_main ->
248 checkTc (maybeToBool maybe_main) noMainErr
253 -- Backsubstitution. This must be done last.
254 -- Even tcSimplifyTop may do some unification.
256 all_binds = imp_data_binds `AndMonoBinds`
257 imp_cls_binds `AndMonoBinds`
258 val_binds `AndMonoBinds`
259 inst_binds `AndMonoBinds`
260 cls_dm_binds `AndMonoBinds`
261 const_inst_binds `AndMonoBinds`
264 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', really_final_env) ->
265 tcSetValueEnv really_final_env $
266 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
267 zonkRules rules `thenNF_Tc` \ rules' ->
269 returnTc (really_final_env,
270 (TcResults { tc_binds = all_binds',
271 tc_tycons = local_tycons,
272 tc_classes = local_classes,
273 tc_insts = inst_info,
274 tc_fords = foi_decls ++ foe_decls',
276 tc_env = really_final_env
279 -- End of outer fix loop
280 ) `thenTc` \ (final_env, stuff) ->
283 get_val_decls decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
289 = hsep [ptext SLIT("Module"), quotes (pprModuleName mAIN_Name),
290 ptext SLIT("must include a definition for"), quotes (ptext SLIT("main"))]