2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
12 #include "HsVersions.h"
14 import CmdLineOpts ( DynFlag(..), DynFlags, opt_PprStyle_Debug )
15 import HsSyn ( HsModule(..), HsBinds(..), MonoBinds(..), HsDecl(..) )
16 import HsTypes ( toHsType )
17 import RnHsSyn ( RenamedHsModule, RenamedHsDecl )
18 import TcHsSyn ( TypecheckedMonoBinds,
19 TypecheckedForeignDecl, TypecheckedRuleDecl,
20 zonkTopBinds, zonkForeignExports, zonkRules
24 import Inst ( emptyLIE, plusLIE )
25 import TcBinds ( tcTopBinds )
26 import TcClassDcl ( tcClassDecls2, mkImplicitClassBinds )
27 import TcDefaults ( tcDefaults )
28 import TcEnv ( TcEnv, tcExtendGlobalValEnv, tcLookupGlobal_maybe,
29 tcEnvTyCons, tcEnvClasses,
30 tcSetEnv, tcSetInstEnv, initTcEnv, getTcGEnv
32 import TcRules ( tcRules )
33 import TcForeign ( tcForeignImports, tcForeignExports )
34 import TcIfaceSig ( tcInterfaceSigs )
35 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
36 import TcInstUtil ( InstInfo(..) )
37 import TcSimplify ( tcSimplifyTop )
38 import TcTyClsDecls ( tcTyAndClassDecls )
39 import TcTyDecls ( mkImplicitDataBinds )
41 import CoreUnfold ( unfoldingTemplate )
42 import Type ( funResultTy, splitForAllTys )
43 import Bag ( isEmptyBag )
44 import ErrUtils ( printErrorsAndWarnings, dumpIfSet_dyn )
45 import Id ( idType, idName, idUnfolding )
46 import Module ( Module, moduleName, plusModuleEnv )
47 import Name ( nameOccName, isLocallyDefined, isGlobalName,
48 toRdrName, nameEnvElts, emptyNameEnv
50 import TyCon ( TyCon, isDataTyCon, tyConName, tyConGenInfo )
51 import OccName ( isSysOcc )
52 import TyCon ( TyCon, isClassTyCon )
53 import Class ( Class )
54 import PrelNames ( mAIN_Name, mainName )
55 import UniqSupply ( UniqSupply )
56 import Maybes ( maybeToBool )
58 import BasicTypes ( EP(..) )
59 import Bag ( Bag, isEmptyBag )
61 import HscTypes ( PersistentCompilerState(..), HomeSymbolTable,
62 PackageSymbolTable, DFunId,
63 TypeEnv, extendTypeEnv,
64 TyThing(..), groupTyThings )
65 import FiniteMap ( FiniteMap, delFromFM, lookupWithDefaultFM )
68 Outside-world interface:
71 -- Convenient type synonyms first:
74 tc_pcs :: PersistentCompilerState, -- Augmented with imported information,
75 -- (but not stuff from this module)
76 tc_env :: TypeEnv, -- The TypeEnv just for the stuff from this module
77 tc_insts :: [DFunId], -- Instances, just for this module
78 tc_binds :: TypecheckedMonoBinds,
79 tc_fords :: [TypecheckedForeignDecl], -- Foreign import & exports.
80 tc_rules :: [TypecheckedRuleDecl] -- Transformation rules
87 -> PersistentCompilerState
90 -> IO (Maybe (TcEnv, TcResults))
92 typecheckModule dflags this_mod pcs hst (HsModule mod_name _ _ _ decls _ src_loc)
93 = do env <- initTcEnv global_symbol_table
94 (maybe_result, (errs,warns)) <- initTc dflags env src_loc tc_module
95 printErrorsAndWarnings (errs,warns)
96 printTcDump dflags maybe_result
97 if isEmptyBag errs then
102 global_symbol_table = pcs_PST pcs `plusModuleEnv` hst
104 tc_module = fixTc (\ ~(unf_env ,_) -> tcModule pcs hst this_mod decls unf_env)
107 The internal monster:
109 tcModule :: PersistentCompilerState
113 -> TcEnv -- The knot-tied environment
114 -> TcM (TcEnv, TcResults)
116 -- (unf_env :: TcEnv) is used for type-checking interface pragmas
117 -- which is done lazily [ie failure just drops the pragma
118 -- without having any global-failure effect].
120 -- unf_env is also used to get the pragama info
121 -- for imported dfuns and default methods
123 tcModule pcs hst this_mod decls unf_env
124 = -- Type-check the type and class decls
125 tcTyAndClassDecls unf_env decls `thenTc` \ env ->
128 classes = tcEnvClasses env
129 tycons = tcEnvTyCons env -- INCLUDES tycons derived from classes
130 local_classes = filter isLocallyDefined classes
131 local_tycons = [ tc | tc <- tycons,
133 not (isClassTyCon tc)
135 -- For local_tycons, filter out the ones derived from classes
136 -- Otherwise the latter show up in interface files
139 -- Typecheck the instance decls, includes deriving
140 tcInstDecls1 pcs hst unf_env this_mod
141 local_tycons decls `thenTc` \ (pcs_with_insts, inst_env, inst_info, deriv_binds) ->
142 tcSetInstEnv inst_env $
144 -- Default declarations
145 tcDefaults decls `thenTc` \ defaulting_tys ->
146 tcSetDefaultTys defaulting_tys $
148 -- Interface type signatures
149 -- We tie a knot so that the Ids read out of interfaces are in scope
150 -- when we read their pragmas.
151 -- What we rely on is that pragmas are typechecked lazily; if
152 -- any type errors are found (ie there's an inconsistency)
153 -- we silently discard the pragma
154 -- We must do this before mkImplicitDataBinds (which comes next), since
155 -- the latter looks up unpackCStringId, for example, which is usually
157 tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
158 tcExtendGlobalValEnv sig_ids $
160 -- Create any necessary record selector Ids and their bindings
161 -- "Necessary" includes data and newtype declarations
162 -- We don't create bindings for dictionary constructors;
163 -- they are always fully applied, and the bindings are just there
164 -- to support partial applications
165 mkImplicitDataBinds tycons `thenTc` \ (data_ids, imp_data_binds) ->
166 mkImplicitClassBinds classes `thenNF_Tc` \ (cls_ids, imp_cls_binds) ->
168 -- Extend the global value environment with
170 -- (b) record selectors
171 -- (c) class op selectors
172 -- (d) default-method ids... where? I can't see where these are
173 -- put into the envt, and I'm worried that the zonking phase
174 -- will find they aren't there and complain.
175 tcExtendGlobalValEnv data_ids $
176 tcExtendGlobalValEnv cls_ids $
178 -- Foreign import declarations next
179 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
180 tcExtendGlobalValEnv fo_ids $
182 -- Value declarations next.
183 -- We also typecheck any extra binds that came out of the "deriving" process
184 tcTopBinds (get_binds decls `ThenBinds` deriv_binds) `thenTc` \ ((val_binds, env), lie_valdecls) ->
187 -- Foreign export declarations next
188 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
190 -- Second pass over class and instance declarations,
191 -- to compile the bindings themselves.
192 tcInstDecls2 inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
193 tcClassDecls2 decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
194 tcRules decls `thenNF_Tc` \ (lie_rules, rules) ->
196 -- Deal with constant or ambiguous InstIds. How could
197 -- there be ambiguous ones? They can only arise if a
198 -- top-level decl falls under the monomorphism
199 -- restriction, and no subsequent decl instantiates its
200 -- type. (Usually, ambiguous type variables are resolved
201 -- during the generalisation step.)
203 lie_alldecls = lie_valdecls `plusLIE`
204 lie_instdecls `plusLIE`
205 lie_clasdecls `plusLIE`
206 lie_fodecls `plusLIE`
209 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
211 -- Check that Main defines main
212 checkMain this_mod `thenTc_`
214 -- Backsubstitution. This must be done last.
215 -- Even tcSimplifyTop may do some unification.
217 all_binds = imp_data_binds `AndMonoBinds`
218 imp_cls_binds `AndMonoBinds`
219 val_binds `AndMonoBinds`
220 inst_binds `AndMonoBinds`
221 cls_dm_binds `AndMonoBinds`
222 const_inst_binds `AndMonoBinds`
225 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', final_env) ->
227 -- zonkTopBinds puts all the top-level Ids into the tcGEnv
228 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
229 zonkRules rules `thenNF_Tc` \ rules' ->
232 let groups :: FiniteMap Module TypeEnv
233 groups = groupTyThings (nameEnvElts (getTcGEnv final_env))
235 local_type_env :: TypeEnv
236 local_type_env = lookupWithDefaultFM groups emptyNameEnv this_mod
238 new_pst :: PackageSymbolTable
239 new_pst = extendTypeEnv (pcs_PST pcs) (delFromFM groups this_mod)
241 final_pcs :: PersistentCompilerState
242 final_pcs = pcs_with_insts {pcs_PST = new_pst}
244 returnTc (final_env, -- WAS: really_final_env,
245 TcResults { tc_pcs = final_pcs,
246 tc_env = local_type_env,
247 tc_binds = all_binds',
248 tc_insts = map iDFunId inst_info,
249 tc_fords = foi_decls ++ foe_decls',
253 get_binds decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
258 checkMain :: Module -> TcM ()
260 | moduleName this_mod == mAIN_Name
261 = tcLookupGlobal_maybe mainName `thenNF_Tc` \ maybe_main ->
263 Just (AnId _) -> returnTc ()
264 other -> addErrTc noMainErr
266 | otherwise = returnTc ()
269 = hsep [ptext SLIT("Module"), quotes (ppr mAIN_Name),
270 ptext SLIT("must include a definition for"), quotes (ptext SLIT("main"))]
274 %************************************************************************
276 \subsection{Dumping output}
278 %************************************************************************
281 printTcDump dflags Nothing = return ()
282 printTcDump dflags (Just (_,results))
283 = do dumpIfSet_dyn dflags Opt_D_dump_types
284 "Type signatures" (dump_sigs results)
285 dumpIfSet_dyn dflags Opt_D_dump_tc
286 "Typechecked" (dump_tc results)
289 = vcat [ppr (tc_binds results),
290 pp_rules (tc_rules results) --,
291 -- ppr_gen_tycons (tc_tycons results)
294 dump_sigs results -- Print type signatures
295 = -- Convert to HsType so that we get source-language style printing
296 -- And sort by RdrName
297 vcat $ map ppr_sig $ sortLt lt_sig $
298 [(toRdrName id, toHsType (idType id))
299 | AnId id <- nameEnvElts (tc_env results),
303 lt_sig (n1,_) (n2,_) = n1 < n2
304 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
306 want_sig id | opt_PprStyle_Debug = True
307 | otherwise = isLocallyDefined n &&
309 not (isSysOcc (nameOccName n))
313 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
314 vcat (map ppr_gen_tycon (filter isLocallyDefined tcs)),
318 -- x&y are now Id's, not CoreExpr's
320 | Just ep <- tyConGenInfo tycon
321 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
323 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
326 = vcat [ ptext SLIT("Rep type:") <+> ppr (funResultTy from_tau),
327 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
328 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
331 (_,from_tau) = splitForAllTys (idType from)
334 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
335 nest 4 (vcat (map ppr rs)),