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, zonkTopBinds,
18 TypecheckedForeignDecl, zonkForeignExports
22 import Inst ( Inst, emptyLIE, plusLIE )
23 import TcBinds ( tcTopBindsAndThen )
24 import TcClassDcl ( tcClassDecls2 )
25 import TcDefaults ( tcDefaults )
26 import TcEnv ( tcExtendGlobalValEnv, tcExtendTypeEnv,
27 getEnvTyCons, getEnvClasses, tcLookupValueMaybe,
28 explicitLookupValueByKey, tcSetValueEnv,
29 tcLookupTyCon, initEnv,
30 ValueEnv, TcTyThing(..)
32 import TcExpr ( tcId )
33 import TcForeign ( tcForeignImports, tcForeignExports )
34 import TcIfaceSig ( tcInterfaceSigs )
35 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
36 import TcInstUtil ( buildInstanceEnvs, classDataCon, InstInfo )
37 import TcSimplify ( tcSimplifyTop )
38 import TcTyClsDecls ( tcTyAndClassDecls )
39 import TcTyDecls ( mkDataBinds )
40 import TcType ( TcType, typeToTcType,
45 import RnMonad ( RnNameSupply, getIfaceFixities, Fixities, InterfaceDetails )
46 import Bag ( isEmptyBag )
47 import ErrUtils ( Message,
48 pprBagOfErrors, dumpIfSet
50 import Id ( Id, idType )
51 import Module ( pprModule )
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 )
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:
77 = (TypecheckedMonoBinds,
79 Bag InstInfo, -- Instance declaration information
80 [TypecheckedForeignDecl], -- foreign import & exports.
82 [Id] -- The thin-air Ids
91 -> IO (Maybe TcResults)
93 typecheckModule us rn_name_supply iface_det mod
94 = initTc us initEnv (tcModule rn_name_supply (getIfaceFixities iface_det) mod)
95 >>= \ (maybe_result, warns, errs) ->
100 -- write the thin-air Id map
101 (case maybe_result of
102 Just (_, _, _, _, _, _, thin_air_ids) -> setThinAirIds thin_air_ids
106 dumpIfSet opt_D_dump_tc "Typechecked"
107 (case maybe_result of
108 Just (binds, _, _, _, _, _, _) -> ppr binds
109 Nothing -> text "Typecheck failed") >>
111 return (if isEmptyBag errs then
117 | isEmptyBag errs = return ()
118 | otherwise = printErrs (pprBagOfErrors errs)
121 The internal monster:
123 tcModule :: RnNameSupply -- for renaming derivings
124 -> Fixities -- needed for Show/Read derivings.
125 -> RenamedHsModule -- input
126 -> TcM s TcResults -- output
128 tcModule rn_name_supply fixities
129 (HsModule mod_name verion exports imports decls src_loc)
130 = tcAddSrcLoc src_loc $ -- record where we're starting
132 fixTc (\ ~(unf_env ,_) ->
133 -- unf_env is used for type-checking interface pragmas
134 -- which is done lazily [ie failure just drops the pragma
135 -- without having any global-failure effect].
137 -- unf_env is also used to get the pragam info
138 -- for imported dfuns and default methods
140 -- The knot for instance information. This isn't used at all
141 -- till we type-check value declarations
142 fixTc ( \ ~(rec_inst_mapper, _, _, _) ->
144 -- Type-check the type and class decls
145 tcTyAndClassDecls unf_env rec_inst_mapper decls `thenTc` \ env ->
147 -- Typecheck the instance decls, includes deriving
149 tcInstDecls1 unf_env decls mod_name fixities rn_name_supply
150 ) `thenTc` \ (inst_info, deriv_binds) ->
152 buildInstanceEnvs inst_info `thenNF_Tc` \ inst_mapper ->
154 returnTc (inst_mapper, env, inst_info, deriv_binds)
156 -- End of inner fix loop
157 ) `thenTc` \ (_, env, inst_info, deriv_binds) ->
161 -- Default declarations
162 tcDefaults decls `thenTc` \ defaulting_tys ->
163 tcSetDefaultTys defaulting_tys $
165 -- Create any necessary record selector Ids and their bindings
166 -- "Necessary" includes data and newtype declarations
167 -- We don't create bindings for dictionary constructors;
168 -- they are always fully applied, and the bindings are just there
169 -- to support partial applications
171 tycons = getEnvTyCons env
172 classes = getEnvClasses env
173 local_tycons = filter isLocallyDefined tycons
174 local_classes = filter isLocallyDefined classes
176 mkDataBinds tycons `thenTc` \ (data_ids, data_binds) ->
178 -- Extend the global value environment with
180 -- (b) record selectors
181 -- (c) class op selectors
182 -- (d) default-method ids... where? I can't see where these are
183 -- put into the envt, and I'm worried that the zonking phase
184 -- will find they aren't there and complain.
185 tcExtendGlobalValEnv data_ids $
186 tcExtendGlobalValEnv (concat (map classSelIds classes)) $
188 -- Extend the TyCon envt with the tycons corresponding to
189 -- the classes, and the global value environment with the
190 -- corresponding data cons.
191 -- They are mentioned in types in interface files.
192 tcExtendGlobalValEnv (map (dataConId . classDataCon) classes) $
193 tcExtendTypeEnv [ (getName tycon, (kindToTcKind (tyConKind tycon), Nothing, ATyCon tycon))
195 let tycon = classTyCon clas
198 -- Interface type signatures
199 -- We tie a knot so that the Ids read out of interfaces are in scope
200 -- when we read their pragmas.
201 -- What we rely on is that pragmas are typechecked lazily; if
202 -- any type errors are found (ie there's an inconsistency)
203 -- we silently discard the pragma
204 tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
205 tcExtendGlobalValEnv sig_ids $
207 -- foreign import declarations next.
208 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
209 tcExtendGlobalValEnv fo_ids $
211 -- Value declarations next.
212 -- We also typecheck any extra binds that came out of the "deriving" process
214 (\ is_rec binds1 (binds2, thing) -> (binds1 `AndMonoBinds` binds2, thing))
215 (get_val_decls decls `ThenBinds` deriv_binds)
216 ( tcGetEnv `thenNF_Tc` \ env ->
217 tcGetUnique `thenNF_Tc` \ uniq ->
218 returnTc ((EmptyMonoBinds, env), emptyLIE)
219 ) `thenTc` \ ((val_binds, final_env), lie_valdecls) ->
222 -- foreign export declarations next.
223 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
225 -- Second pass over class and instance declarations,
226 -- to compile the bindings themselves.
227 tcInstDecls2 inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
228 tcClassDecls2 decls `thenNF_Tc` \ (lie_clasdecls, cls_binds) ->
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`
243 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
245 -- Check that Main defines main
246 (if mod_name == mAIN then
247 tcLookupValueMaybe main_NAME `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 = data_binds `AndMonoBinds`
257 val_binds `AndMonoBinds`
258 inst_binds `AndMonoBinds`
259 cls_binds `AndMonoBinds`
260 const_inst_binds `AndMonoBinds`
263 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', really_final_env) ->
264 tcSetValueEnv really_final_env $
265 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
268 thin_air_ids = map (explicitLookupValueByKey really_final_env . nameUnique) thinAirIdNames
269 -- When looking up the thin-air names we must use
270 -- a global env that includes the zonked locally-defined Ids too
271 -- Hence using really_final_env
273 returnTc (really_final_env,
274 (all_binds', local_tycons, local_classes, inst_info,
275 (foi_decls ++ foe_decls'),
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 (pprModule mAIN),
291 ptext SLIT("must include a definition for"), quotes (ppr main_NAME)]