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, mkImplicitClassBinds )
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 ( 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 Name ( Name, nameUnique, isLocallyDefined, NamedThing(..) )
53 import TyCon ( TyCon, tyConKind )
54 import Class ( Class, classSelIds, classTyCon )
55 import Type ( mkTyConApp, mkForAllTy,
56 boxedTypeKind, getTyVar, Type )
57 import TysWiredIn ( unitTy )
58 import PrelMods ( mAIN_Name )
59 import PrelInfo ( main_NAME, thinAirIdNames, setThinAirIds )
60 import TcUnify ( unifyTauTy )
61 import Unique ( Unique )
62 import UniqSupply ( UniqSupply )
63 import Maybes ( maybeToBool )
65 import Bag ( Bag, isEmptyBag )
71 Outside-world interface:
74 -- Convenient type synonyms first:
77 tc_binds :: TypecheckedMonoBinds,
79 tc_classes :: [Class],
80 tc_insts :: Bag InstInfo, -- Instance declaration information
81 tc_fords :: [TypecheckedForeignDecl], -- Foreign import & exports.
82 tc_rules :: [TypecheckedRuleDecl], -- Transformation rules
84 tc_thinair :: [Id] -- The thin-air Ids
93 -> IO (Maybe TcResults)
95 typecheckModule us rn_name_supply iface_det mod
96 = initTc us initEnv (tcModule rn_name_supply (getIfaceFixities iface_det) mod)
97 >>= \ (maybe_result, warns, errs) ->
99 printErrorsAndWarnings errs warns >>
101 -- write the thin-air Id map
102 (case maybe_result of
103 Just results -> setThinAirIds (tc_thinair results)
107 dumpIfSet opt_D_dump_tc "Typechecked"
108 (case maybe_result of
109 Just results -> ppr (tc_binds results)
111 pp_rules (tc_rules results)
112 Nothing -> text "Typecheck failed") >>
114 return (if isEmptyBag errs then
120 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
121 nest 4 (vcat (map ppr rs)),
125 The internal monster:
127 tcModule :: RnNameSupply -- for renaming derivings
128 -> Fixities -- needed for Show/Read derivings.
129 -> RenamedHsModule -- input
130 -> TcM s TcResults -- output
132 tcModule rn_name_supply fixities
133 (HsModule mod_name verion exports imports decls _ src_loc)
134 = tcAddSrcLoc src_loc $ -- record where we're starting
136 fixTc (\ ~(unf_env ,_) ->
137 -- unf_env is used for type-checking interface pragmas
138 -- which is done lazily [ie failure just drops the pragma
139 -- without having any global-failure effect].
141 -- unf_env is also used to get the pragam info
142 -- for imported dfuns and default methods
144 -- The knot for instance information. This isn't used at all
145 -- till we type-check value declarations
146 fixTc ( \ ~(rec_inst_mapper, _, _, _) ->
148 -- Type-check the type and class decls
149 tcTyAndClassDecls unf_env rec_inst_mapper decls `thenTc` \ env ->
151 -- Typecheck the instance decls, includes deriving
153 tcInstDecls1 unf_env decls mod_name fixities rn_name_supply
154 ) `thenTc` \ (inst_info, deriv_binds) ->
156 buildInstanceEnvs inst_info `thenNF_Tc` \ inst_mapper ->
158 returnTc (inst_mapper, env, inst_info, deriv_binds)
160 -- End of inner fix loop
161 ) `thenTc` \ (_, env, inst_info, deriv_binds) ->
165 -- Default declarations
166 tcDefaults decls `thenTc` \ defaulting_tys ->
167 tcSetDefaultTys defaulting_tys $
169 -- Create any necessary record selector Ids and their bindings
170 -- "Necessary" includes data and newtype declarations
171 -- We don't create bindings for dictionary constructors;
172 -- they are always fully applied, and the bindings are just there
173 -- to support partial applications
175 tycons = getEnvTyCons env
176 classes = getEnvClasses env
177 local_tycons = filter isLocallyDefined tycons
178 local_classes = filter isLocallyDefined classes
180 mkImplicitDataBinds tycons `thenTc` \ (data_ids, imp_data_binds) ->
181 mkImplicitClassBinds classes `thenNF_Tc` \ (cls_ids, imp_cls_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 cls_ids $
193 -- Extend the TyCon envt with the tycons corresponding to
195 -- They are mentioned in types in interface files.
196 tcExtendTypeEnv [ (getName tycon, (kindToTcKind (tyConKind tycon), Nothing, ATyCon tycon))
198 let tycon = classTyCon clas
201 -- Interface type signatures
202 -- We tie a knot so that the Ids read out of interfaces are in scope
203 -- when we read their pragmas.
204 -- What we rely on is that pragmas are typechecked lazily; if
205 -- any type errors are found (ie there's an inconsistency)
206 -- we silently discard the pragma
207 tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
208 tcExtendGlobalValEnv sig_ids $
210 -- foreign import declarations next.
211 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
212 tcExtendGlobalValEnv fo_ids $
214 -- Value declarations next.
215 -- We also typecheck any extra binds that came out of the "deriving" process
217 (\ is_rec binds1 (binds2, thing) -> (binds1 `AndMonoBinds` binds2, thing))
218 (get_val_decls decls `ThenBinds` deriv_binds)
219 ( tcGetEnv `thenNF_Tc` \ env ->
220 tcGetUnique `thenNF_Tc` \ uniq ->
221 returnTc ((EmptyMonoBinds, env), emptyLIE)
222 ) `thenTc` \ ((val_binds, final_env), lie_valdecls) ->
225 -- foreign export declarations next.
226 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
228 -- Second pass over class and instance declarations,
229 -- to compile the bindings themselves.
230 tcInstDecls2 inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
231 tcClassDecls2 decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
232 tcRules decls `thenNF_Tc` \ (lie_rules, rules) ->
235 -- Deal with constant or ambiguous InstIds. How could
236 -- there be ambiguous ones? They can only arise if a
237 -- top-level decl falls under the monomorphism
238 -- restriction, and no subsequent decl instantiates its
239 -- type. (Usually, ambiguous type variables are resolved
240 -- during the generalisation step.)
242 lie_alldecls = lie_valdecls `plusLIE`
243 lie_instdecls `plusLIE`
244 lie_clasdecls `plusLIE`
245 lie_fodecls `plusLIE`
248 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
250 -- Check that Main defines main
251 (if mod_name == mAIN_Name then
252 tcLookupValueMaybe main_NAME `thenNF_Tc` \ maybe_main ->
253 checkTc (maybeToBool maybe_main) noMainErr
258 -- Backsubstitution. This must be done last.
259 -- Even tcSimplifyTop may do some unification.
261 all_binds = imp_data_binds `AndMonoBinds`
262 imp_cls_binds `AndMonoBinds`
263 val_binds `AndMonoBinds`
264 inst_binds `AndMonoBinds`
265 cls_dm_binds `AndMonoBinds`
266 const_inst_binds `AndMonoBinds`
269 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', really_final_env) ->
270 tcSetValueEnv really_final_env $
271 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
272 zonkRules rules `thenNF_Tc` \ rules' ->
275 thin_air_ids = map (explicitLookupValueByKey really_final_env . nameUnique) thinAirIdNames
276 -- When looking up the thin-air names we must use
277 -- a global env that includes the zonked locally-defined Ids too
278 -- Hence using really_final_env
280 returnTc (really_final_env,
281 (TcResults { tc_binds = all_binds',
282 tc_tycons = local_tycons,
283 tc_classes = local_classes,
284 tc_insts = inst_info,
285 tc_fords = foi_decls ++ foe_decls',
287 tc_env = really_final_env,
288 tc_thinair = thin_air_ids
292 -- End of outer fix loop
293 ) `thenTc` \ (final_env, stuff) ->
296 get_val_decls decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
302 = hsep [ptext SLIT("Module"), quotes (pprModuleName mAIN_Name),
303 ptext SLIT("must include a definition for"), quotes (ppr main_NAME)]