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 ( HsBinds(..), MonoBinds(..), HsDecl(..) )
16 import HsTypes ( toHsType )
17 import RnHsSyn ( RenamedHsDecl )
18 import TcHsSyn ( TypecheckedMonoBinds,
19 TypecheckedForeignDecl, TypecheckedRuleDecl,
20 zonkTopBinds, zonkForeignExports, zonkRules
24 import Inst ( plusLIE )
25 import TcBinds ( tcTopBinds )
26 import TcClassDcl ( tcClassDecls2, mkImplicitClassBinds )
27 import TcDefaults ( tcDefaults )
28 import TcEnv ( TcEnv, InstInfo(iDFunId), tcExtendGlobalValEnv,
29 tcEnvTyCons, tcEnvClasses, isLocalThing,
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 TcSimplify ( tcSimplifyTop )
37 import TcTyClsDecls ( tcTyAndClassDecls )
38 import TcTyDecls ( mkImplicitDataBinds )
40 import CoreUnfold ( unfoldingTemplate )
41 import Type ( funResultTy, splitForAllTys )
42 import Bag ( isEmptyBag )
43 import ErrUtils ( printErrorsAndWarnings, dumpIfSet_dyn )
44 import Id ( idType, idName, idUnfolding )
45 import Module ( Module, plusModuleEnv )
46 import Name ( Name, nameOccName, isLocallyDefined, isGlobalName, getName,
47 toRdrName, nameEnvElts, lookupNameEnv, mkNameEnv
49 import TyCon ( tyConGenInfo, isClassTyCon )
50 import OccName ( isSysOcc )
51 import Maybes ( thenMaybe )
53 import BasicTypes ( EP(..), Fixity )
54 import Bag ( isEmptyBag )
56 import HscTypes ( PersistentCompilerState(..), HomeSymbolTable, HomeIfaceTable,
57 PackageSymbolTable, DFunId, ModIface(..),
58 TypeEnv, extendTypeEnv, lookupTable,
59 TyThing(..), groupTyThings )
60 import List ( partition )
63 Outside-world interface:
66 -- Convenient type synonyms first:
69 tc_pcs :: PersistentCompilerState, -- Augmented with imported information,
70 -- (but not stuff from this module)
72 -- All these fields have info *just for this module*
73 tc_env :: TypeEnv, -- The top level TypeEnv
74 tc_insts :: [DFunId], -- Instances
75 tc_binds :: TypecheckedMonoBinds, -- Bindings
76 tc_fords :: [TypecheckedForeignDecl], -- Foreign import & exports.
77 tc_rules :: [TypecheckedRuleDecl] -- Transformation rules
84 -> PersistentCompilerState
85 -> HomeSymbolTable -> HomeIfaceTable
87 -> IO (Maybe TcResults)
89 typecheckModule dflags this_mod pcs hst hit decls
90 = do env <- initTcEnv global_symbol_table
92 (maybe_result, (warns,errs)) <- initTc dflags env tc_module
94 let { maybe_tc_result :: Maybe TcResults ;
95 maybe_tc_result = case maybe_result of
97 Just (_,r) -> Just r }
99 printErrorsAndWarnings (errs,warns)
100 printTcDump dflags maybe_tc_result
102 if isEmptyBag errs then
103 return maybe_tc_result
107 global_symbol_table = pcs_PST pcs `plusModuleEnv` hst
109 tc_module :: TcM (TcEnv, TcResults)
110 tc_module = fixTc (\ ~(unf_env ,_) -> tcModule pcs hst get_fixity this_mod decls unf_env)
114 get_fixity :: Name -> Maybe Fixity
115 get_fixity nm = lookupTable hit pit nm `thenMaybe` \ iface ->
116 lookupNameEnv (mi_fixities iface) nm
119 The internal monster:
121 tcModule :: PersistentCompilerState
123 -> (Name -> Maybe Fixity)
126 -> TcEnv -- The knot-tied environment
127 -> TcM (TcEnv, TcResults)
129 -- (unf_env :: TcEnv) is used for type-checking interface pragmas
130 -- which is done lazily [ie failure just drops the pragma
131 -- without having any global-failure effect].
133 -- unf_env is also used to get the pragama info
134 -- for imported dfuns and default methods
136 tcModule pcs hst get_fixity this_mod decls unf_env
137 = -- Type-check the type and class decls
138 tcTyAndClassDecls unf_env decls `thenTc` \ env ->
141 classes = tcEnvClasses env
142 tycons = tcEnvTyCons env -- INCLUDES tycons derived from classes
143 local_tycons = [ tc | tc <- tycons,
145 not (isClassTyCon tc)
147 -- For local_tycons, filter out the ones derived from classes
148 -- Otherwise the latter show up in interface files
151 -- Typecheck the instance decls, includes deriving
152 tcInstDecls1 (pcs_insts pcs) (pcs_PRS pcs)
153 hst unf_env get_fixity this_mod
154 local_tycons decls `thenTc` \ (new_pcs_insts, inst_env, local_inst_info, deriv_binds) ->
155 tcSetInstEnv inst_env $
157 -- Default declarations
158 tcDefaults decls `thenTc` \ defaulting_tys ->
159 tcSetDefaultTys defaulting_tys $
161 -- Interface type signatures
162 -- We tie a knot so that the Ids read out of interfaces are in scope
163 -- when we read their pragmas.
164 -- What we rely on is that pragmas are typechecked lazily; if
165 -- any type errors are found (ie there's an inconsistency)
166 -- we silently discard the pragma
167 -- We must do this before mkImplicitDataBinds (which comes next), since
168 -- the latter looks up unpackCStringId, for example, which is usually
170 tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
171 tcExtendGlobalValEnv sig_ids $
173 -- Create any necessary record selector Ids and their bindings
174 -- "Necessary" includes data and newtype declarations
175 -- We don't create bindings for dictionary constructors;
176 -- they are always fully applied, and the bindings are just there
177 -- to support partial applications
178 mkImplicitDataBinds tycons `thenTc` \ (data_ids, imp_data_binds) ->
179 mkImplicitClassBinds classes `thenNF_Tc` \ (cls_ids, imp_cls_binds) ->
181 -- Extend the global value environment with
183 -- (b) record selectors
184 -- (c) class op selectors
185 -- (d) default-method ids... where? I can't see where these are
186 -- put into the envt, and I'm worried that the zonking phase
187 -- will find they aren't there and complain.
188 tcExtendGlobalValEnv data_ids $
189 tcExtendGlobalValEnv cls_ids $
191 -- Foreign import declarations next
192 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
193 tcExtendGlobalValEnv fo_ids $
195 -- Value declarations next.
196 -- We also typecheck any extra binds that came out of the "deriving" process
197 tcTopBinds (get_binds decls `ThenBinds` deriv_binds) `thenTc` \ ((val_binds, env), lie_valdecls) ->
200 -- Foreign export declarations next
201 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
203 -- Second pass over class and instance declarations,
204 -- to compile the bindings themselves.
205 tcInstDecls2 local_inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
206 tcClassDecls2 decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
207 tcRules (pcs_rules pcs) this_mod decls `thenNF_Tc` \ (new_pcs_rules, lie_rules, local_rules) ->
209 -- Deal with constant or ambiguous InstIds. How could
210 -- there be ambiguous ones? They can only arise if a
211 -- top-level decl falls under the monomorphism
212 -- restriction, and no subsequent decl instantiates its
213 -- type. (Usually, ambiguous type variables are resolved
214 -- during the generalisation step.)
216 lie_alldecls = lie_valdecls `plusLIE`
217 lie_instdecls `plusLIE`
218 lie_clasdecls `plusLIE`
219 lie_fodecls `plusLIE`
222 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
224 -- Backsubstitution. This must be done last.
225 -- Even tcSimplifyTop may do some unification.
227 all_binds = imp_data_binds `AndMonoBinds`
228 imp_cls_binds `AndMonoBinds`
229 val_binds `AndMonoBinds`
230 inst_binds `AndMonoBinds`
231 cls_dm_binds `AndMonoBinds`
232 const_inst_binds `AndMonoBinds`
235 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', final_env) ->
237 -- zonkTopBinds puts all the top-level Ids into the tcGEnv
238 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
239 zonkRules local_rules `thenNF_Tc` \ local_rules' ->
242 let (local_things, imported_things) = partition (isLocalThing this_mod)
243 (nameEnvElts (getTcGEnv final_env))
245 local_type_env :: TypeEnv
246 local_type_env = mkNameEnv [(getName thing, thing) | thing <- local_things]
248 new_pst :: PackageSymbolTable
249 new_pst = extendTypeEnv (pcs_PST pcs) (groupTyThings imported_things)
251 final_pcs :: PersistentCompilerState
252 final_pcs = pcs { pcs_PST = new_pst,
253 pcs_insts = new_pcs_insts,
254 pcs_rules = new_pcs_rules
258 TcResults { tc_pcs = final_pcs,
259 tc_env = local_type_env,
260 tc_binds = all_binds',
261 tc_insts = map iDFunId local_inst_info,
262 tc_fords = foi_decls ++ foe_decls',
263 tc_rules = local_rules'
266 get_binds decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
271 %************************************************************************
273 \subsection{Dumping output}
275 %************************************************************************
278 printTcDump dflags Nothing = return ()
279 printTcDump dflags (Just results)
280 = do dumpIfSet_dyn dflags Opt_D_dump_types
281 "Type signatures" (dump_sigs results)
282 dumpIfSet_dyn dflags Opt_D_dump_tc
283 "Typechecked" (dump_tc results)
286 = vcat [ppr (tc_binds results),
287 pp_rules (tc_rules results),
288 ppr_gen_tycons [tc | ATyCon tc <- nameEnvElts (tc_env results)]
291 dump_sigs results -- Print type signatures
292 = -- Convert to HsType so that we get source-language style printing
293 -- And sort by RdrName
294 vcat $ map ppr_sig $ sortLt lt_sig $
295 [(toRdrName id, toHsType (idType id))
296 | AnId id <- nameEnvElts (tc_env results),
300 lt_sig (n1,_) (n2,_) = n1 < n2
301 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
303 want_sig id | opt_PprStyle_Debug = True
304 | otherwise = isLocallyDefined n &&
306 not (isSysOcc (nameOccName n))
310 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
311 vcat (map ppr_gen_tycon (filter isLocallyDefined tcs)),
315 -- x&y are now Id's, not CoreExpr's
317 | Just ep <- tyConGenInfo tycon
318 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
320 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
323 = vcat [ ptext SLIT("Rep type:") <+> ppr (funResultTy from_tau),
324 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
325 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
328 (_,from_tau) = splitForAllTys (idType from)
331 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
332 nest 4 (vcat (map ppr rs)),