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, tyConClass_maybe )
52 import Class ( Class )
53 import PrelInfo ( mAIN_Name )
54 import Unique ( mainKey )
55 import UniqSupply ( UniqSupply )
56 import Maybes ( maybeToBool )
58 import Bag ( Bag, isEmptyBag )
62 Outside-world interface:
65 -- Convenient type synonyms first:
68 tc_binds :: TypecheckedMonoBinds,
70 tc_classes :: [Class],
71 tc_insts :: Bag InstInfo, -- Instance declaration information
72 tc_fords :: [TypecheckedForeignDecl], -- Foreign import & exports.
73 tc_rules :: [TypecheckedRuleDecl], -- Transformation rules
83 -> IO (Maybe TcResults)
85 typecheckModule us rn_name_supply fixity_env mod
86 = initTc us initEnv (tcModule rn_name_supply fixity_env mod) >>= \ (maybe_result, warns, errs) ->
88 printErrorsAndWarnings errs warns >>
92 Just results -> dumpIfSet opt_D_dump_types "Type signatures" (dump_sigs results) >>
93 dumpIfSet opt_D_dump_tc "Typechecked" (dump_tc results)
96 return (if isEmptyBag errs then
102 = ppr (tc_binds results) $$ pp_rules (tc_rules results)
104 dump_sigs results -- Print type signatures
105 = -- Convert to HsType so that we get source-language style printing
106 -- And sort by RdrName
107 vcat $ map ppr_sig $ sortLt lt_sig $
108 [(toRdrName id, toHsType (idType id)) | id <- nameEnvElts (tc_env results),
112 lt_sig (n1,_) (n2,_) = n1 < n2
113 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
115 want_sig id | opt_PprStyle_Debug = True
116 | otherwise = isLocallyDefined n &&
118 not (isSysOcc (nameOccName n))
123 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
124 nest 4 (vcat (map ppr rs)),
128 The internal monster:
130 tcModule :: RnNameSupply -- for renaming derivings
131 -> FixityEnv -- needed for Show/Read derivings.
132 -> RenamedHsModule -- input
133 -> TcM s TcResults -- output
135 tcModule rn_name_supply fixities
136 (HsModule mod_name _ _ _ decls _ src_loc)
137 = tcAddSrcLoc src_loc $ -- record where we're starting
139 fixTc (\ ~(unf_env ,_) ->
140 -- unf_env is used for type-checking interface pragmas
141 -- which is done lazily [ie failure just drops the pragma
142 -- without having any global-failure effect].
144 -- unf_env is also used to get the pragam info
145 -- for imported dfuns and default methods
147 -- Type-check the type and class decls
148 tcTyAndClassDecls unf_env decls `thenTc` \ env ->
150 -- Typecheck the instance decls, includes deriving
153 tcInstDecls1 unf_env decls
154 (mkThisModule mod_name)
155 fixities rn_name_supply `thenTc` \ (inst_info, deriv_binds) ->
157 buildInstanceEnv inst_info `thenNF_Tc` \ inst_env ->
159 tcSetInstEnv inst_env $
161 classes = getEnvClasses env
162 tycons = getEnvTyCons env -- INCLUDES tycons derived from classes
163 local_classes = filter isLocallyDefined classes
164 local_tycons = [ tc | tc <- tycons,
166 Nothing <- [tyConClass_maybe tc]
168 -- For local_tycons, filter out the ones derived from classes
169 -- Otherwise the latter show up in interface files
172 -- Default declarations
173 tcDefaults decls `thenTc` \ defaulting_tys ->
174 tcSetDefaultTys defaulting_tys $
176 -- Interface type signatures
177 -- We tie a knot so that the Ids read out of interfaces are in scope
178 -- when we read their pragmas.
179 -- What we rely on is that pragmas are typechecked lazily; if
180 -- any type errors are found (ie there's an inconsistency)
181 -- we silently discard the pragma
182 -- We must do this before mkImplicitDataBinds (which comes next), since
183 -- the latter looks up unpackCStringId, for example, which is usually
185 tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
186 tcExtendGlobalValEnv sig_ids $
188 -- Create any necessary record selector Ids and their bindings
189 -- "Necessary" includes data and newtype declarations
190 -- We don't create bindings for dictionary constructors;
191 -- they are always fully applied, and the bindings are just there
192 -- to support partial applications
193 mkImplicitDataBinds tycons `thenTc` \ (data_ids, imp_data_binds) ->
194 mkImplicitClassBinds classes `thenNF_Tc` \ (cls_ids, imp_cls_binds) ->
196 -- Extend the global value environment with
198 -- (b) record selectors
199 -- (c) class op selectors
200 -- (d) default-method ids... where? I can't see where these are
201 -- put into the envt, and I'm worried that the zonking phase
202 -- will find they aren't there and complain.
203 tcExtendGlobalValEnv data_ids $
204 tcExtendGlobalValEnv cls_ids $
206 -- foreign import declarations next.
207 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
208 tcExtendGlobalValEnv fo_ids $
210 -- Value declarations next.
211 -- We also typecheck any extra binds that came out of the "deriving" process
213 (\ is_rec binds1 (binds2, thing) -> (binds1 `AndMonoBinds` binds2, thing))
214 (get_val_decls decls `ThenBinds` deriv_binds)
215 ( tcGetEnv `thenNF_Tc` \ env ->
216 tcGetUnique `thenNF_Tc` \ uniq ->
217 returnTc ((EmptyMonoBinds, env), emptyLIE)
218 ) `thenTc` \ ((val_binds, final_env), lie_valdecls) ->
221 -- foreign export declarations next.
222 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
224 -- Second pass over class and instance declarations,
225 -- to compile the bindings themselves.
226 tcInstDecls2 inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
227 tcClassDecls2 decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
228 tcRules decls `thenNF_Tc` \ (lie_rules, rules) ->
231 -- Deal with constant or ambiguous InstIds. How could
232 -- there be ambiguous ones? They can only arise if a
233 -- top-level decl falls under the monomorphism
234 -- restriction, and no subsequent decl instantiates its
235 -- type. (Usually, ambiguous type variables are resolved
236 -- during the generalisation step.)
238 lie_alldecls = lie_valdecls `plusLIE`
239 lie_instdecls `plusLIE`
240 lie_clasdecls `plusLIE`
241 lie_fodecls `plusLIE`
244 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
246 -- Check that Main defines main
247 (if mod_name == mAIN_Name then
248 tcLookupValueByKeyMaybe mainKey `thenNF_Tc` \ maybe_main ->
249 checkTc (maybeToBool maybe_main) noMainErr
254 -- Backsubstitution. This must be done last.
255 -- Even tcSimplifyTop may do some unification.
257 all_binds = imp_data_binds `AndMonoBinds`
258 imp_cls_binds `AndMonoBinds`
259 val_binds `AndMonoBinds`
260 inst_binds `AndMonoBinds`
261 cls_dm_binds `AndMonoBinds`
262 const_inst_binds `AndMonoBinds`
265 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', really_final_env) ->
266 tcSetValueEnv really_final_env $
267 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
268 zonkRules rules `thenNF_Tc` \ rules' ->
270 returnTc (really_final_env,
271 (TcResults { tc_binds = all_binds',
272 tc_tycons = local_tycons,
273 tc_classes = local_classes,
274 tc_insts = inst_info,
275 tc_fords = foi_decls ++ foe_decls',
277 tc_env = really_final_env
280 -- End of outer fix loop
281 ) `thenTc` \ (final_env, stuff) ->
284 get_val_decls decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
290 = hsep [ptext SLIT("Module"), quotes (pprModuleName mAIN_Name),
291 ptext SLIT("must include a definition for"), quotes (ptext SLIT("main"))]