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, showPass )
44 import Id ( idType, idUnfolding )
45 import Module ( Module )
46 import Name ( Name, toRdrName )
47 import Name ( nameEnvElts, lookupNameEnv )
48 import TyCon ( tyConGenInfo )
50 import BasicTypes ( EP(..), Fixity )
51 import Bag ( isEmptyBag )
53 import HscTypes ( PersistentCompilerState(..), HomeSymbolTable,
54 PackageTypeEnv, DFunId, ModIface(..),
55 TypeEnv, extendTypeEnvList,
56 TyThing(..), mkTypeEnv )
57 import List ( partition )
60 Outside-world interface:
63 -- Convenient type synonyms first:
66 tc_pcs :: PersistentCompilerState, -- Augmented with imported information,
67 -- (but not stuff from this module)
69 -- All these fields have info *just for this module*
70 tc_env :: TypeEnv, -- The top level TypeEnv
71 tc_insts :: [DFunId], -- Instances
72 tc_binds :: TypecheckedMonoBinds, -- Bindings
73 tc_fords :: [TypecheckedForeignDecl], -- Foreign import & exports.
74 tc_rules :: [TypecheckedRuleDecl] -- Transformation rules
81 -> PersistentCompilerState
83 -> ModIface -- Iface for this module
84 -> PrintUnqualified -- For error printing
86 -> IO (Maybe TcResults)
88 typecheckModule dflags this_mod pcs hst mod_iface unqual decls
89 = do { showPass dflags "Typechecker";
90 ; env <- initTcEnv hst (pcs_PTE pcs)
92 ; (maybe_tc_result, (warns,errs)) <- initTc dflags env (tcModule pcs hst get_fixity this_mod decls)
94 ; printErrorsAndWarnings unqual (errs,warns)
95 ; printTcDump dflags maybe_tc_result
97 ; if isEmptyBag errs then
98 return maybe_tc_result
103 fixity_env = mi_fixities mod_iface
105 get_fixity :: Name -> Maybe Fixity
106 get_fixity nm = lookupNameEnv fixity_env nm
109 The internal monster:
111 tcModule :: PersistentCompilerState
113 -> (Name -> Maybe Fixity)
118 tcModule pcs hst get_fixity this_mod decls
119 = -- Type-check the type and class decls
120 fixTc (\ ~(unf_env, _, _, _, _) ->
121 -- (unf_env :: RecTcEnv) is used for type-checking interface pragmas
122 -- which is done lazily [ie failure just drops the pragma
123 -- without having any global-failure effect].
125 -- unf_env is also used to get the pragama info
126 -- for imported dfuns and default methods
128 -- traceTc (text "Tc1") `thenNF_Tc_`
129 tcTyAndClassDecls unf_env decls `thenTc` \ env ->
132 classes = tcEnvClasses env
133 tycons = tcEnvTyCons env -- INCLUDES tycons derived from classes
136 -- Typecheck the instance decls, includes deriving
137 -- traceTc (text "Tc2") `thenNF_Tc_`
138 tcInstDecls1 (pcs_insts pcs) (pcs_PRS pcs)
139 hst unf_env get_fixity this_mod
140 tycons decls `thenTc` \ (new_pcs_insts, inst_env, local_inst_info, deriv_binds) ->
141 tcSetInstEnv inst_env $
143 -- Interface type signatures
144 -- We tie a knot so that the Ids read out of interfaces are in scope
145 -- when we read their pragmas.
146 -- What we rely on is that pragmas are typechecked lazily; if
147 -- any type errors are found (ie there's an inconsistency)
148 -- we silently discard the pragma
149 -- We must do this before mkImplicitDataBinds (which comes next), since
150 -- the latter looks up unpackCStringId, for example, which is usually
152 -- traceTc (text "Tc3") `thenNF_Tc_`
153 tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
154 tcExtendGlobalValEnv sig_ids $
156 -- Create any necessary record selector Ids and their bindings
157 -- "Necessary" includes data and newtype declarations
158 -- We don't create bindings for dictionary constructors;
159 -- they are always fully applied, and the bindings are just there
160 -- to support partial applications
161 mkImplicitDataBinds this_mod tycons `thenTc` \ (data_ids, imp_data_binds) ->
162 mkImplicitClassBinds this_mod classes `thenNF_Tc` \ (cls_ids, imp_cls_binds) ->
164 -- Extend the global value environment with
166 -- (b) record selectors
167 -- (c) class op selectors
168 -- (d) default-method ids... where? I can't see where these are
169 -- put into the envt, and I'm worried that the zonking phase
170 -- will find they aren't there and complain.
171 tcExtendGlobalValEnv data_ids $
172 tcExtendGlobalValEnv cls_ids $
173 tcGetEnv `thenTc` \ unf_env ->
174 returnTc (unf_env, new_pcs_insts, local_inst_info, deriv_binds,
175 imp_data_binds `AndMonoBinds` imp_cls_binds)
176 ) `thenTc` \ (env, new_pcs_insts, local_inst_info, deriv_binds, data_cls_binds) ->
180 -- Foreign import declarations next
181 -- traceTc (text "Tc4") `thenNF_Tc_`
182 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
183 tcExtendGlobalValEnv fo_ids $
185 -- Default declarations
186 tcDefaults decls `thenTc` \ defaulting_tys ->
187 tcSetDefaultTys defaulting_tys $
189 -- Value declarations next.
190 -- We also typecheck any extra binds that came out of the "deriving" process
191 -- traceTc (text "Tc5") `thenNF_Tc_`
192 tcTopBinds (get_binds decls `ThenBinds` deriv_binds) `thenTc` \ ((val_binds, env), lie_valdecls) ->
195 -- Foreign export declarations next
196 -- traceTc (text "Tc6") `thenNF_Tc_`
197 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
199 -- Second pass over class and instance declarations,
200 -- to compile the bindings themselves.
201 -- traceTc (text "Tc7") `thenNF_Tc_`
202 tcInstDecls2 local_inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
203 -- traceTc (text "Tc8") `thenNF_Tc_`
204 tcClassDecls2 this_mod decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
205 tcRules (pcs_rules pcs) this_mod decls `thenNF_Tc` \ (new_pcs_rules, lie_rules, local_rules) ->
207 -- Deal with constant or ambiguous InstIds. How could
208 -- there be ambiguous ones? They can only arise if a
209 -- top-level decl falls under the monomorphism
210 -- restriction, and no subsequent decl instantiates its
211 -- type. (Usually, ambiguous type variables are resolved
212 -- during the generalisation step.)
214 lie_alldecls = lie_valdecls `plusLIE`
215 lie_instdecls `plusLIE`
216 lie_clasdecls `plusLIE`
217 lie_fodecls `plusLIE`
220 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
222 -- Backsubstitution. This must be done last.
223 -- Even tcSimplifyTop may do some unification.
225 all_binds = data_cls_binds `AndMonoBinds`
226 val_binds `AndMonoBinds`
227 inst_binds `AndMonoBinds`
228 cls_dm_binds `AndMonoBinds`
229 const_inst_binds `AndMonoBinds`
232 -- traceTc (text "Tc9") `thenNF_Tc_`
233 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', final_env) ->
235 -- zonkTopBinds puts all the top-level Ids into the tcGEnv
236 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
237 zonkRules local_rules `thenNF_Tc` \ local_rules' ->
240 let (local_things, imported_things) = partition (isLocalThing this_mod)
241 (nameEnvElts (getTcGEnv final_env))
243 local_type_env :: TypeEnv
244 local_type_env = mkTypeEnv local_things
246 new_pte :: PackageTypeEnv
247 new_pte = extendTypeEnvList (pcs_PTE pcs) imported_things
249 final_pcs :: PersistentCompilerState
250 final_pcs = pcs { pcs_PTE = new_pte,
251 pcs_insts = new_pcs_insts,
252 pcs_rules = new_pcs_rules
255 -- traceTc (text "Tc10") `thenNF_Tc_`
256 returnTc (TcResults { tc_pcs = final_pcs,
257 tc_env = local_type_env,
258 tc_binds = all_binds',
259 tc_insts = map iDFunId local_inst_info,
260 tc_fords = foi_decls ++ foe_decls',
261 tc_rules = local_rules'
265 get_binds decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
270 %************************************************************************
272 \subsection{Dumping output}
274 %************************************************************************
277 printTcDump dflags Nothing = return ()
278 printTcDump dflags (Just results)
279 = do dumpIfSet_dyn dflags Opt_D_dump_types
280 "Type signatures" (dump_sigs results)
281 dumpIfSet_dyn dflags Opt_D_dump_tc
282 "Typechecked" (dump_tc results)
285 = vcat [ppr (tc_binds results),
286 pp_rules (tc_rules results),
287 ppr_gen_tycons [tc | ATyCon tc <- nameEnvElts (tc_env results)]
290 dump_sigs results -- Print type signatures
291 = -- Convert to HsType so that we get source-language style printing
292 -- And sort by RdrName
293 vcat $ map ppr_sig $ sortLt lt_sig $
294 [ (toRdrName id, toHsType (idType id))
295 | AnId id <- nameEnvElts (tc_env results),
299 lt_sig (n1,_) (n2,_) = n1 < n2
300 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
302 want_sig id | opt_PprStyle_Debug = True
303 | otherwise = True -- For now
305 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
306 vcat (map ppr_gen_tycon tcs),
310 -- x&y are now Id's, not CoreExpr's
312 | Just ep <- tyConGenInfo tycon
313 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
315 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
318 = vcat [ ptext SLIT("Rep type:") <+> ppr (funResultTy from_tau),
319 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
320 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
323 (_,from_tau) = splitForAllTys (idType from)
326 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
327 nest 4 (vcat (map ppr rs)),