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 RecTcEnv, 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, 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
85 -> IO (Maybe TcResults)
87 typecheckModule dflags this_mod pcs hst mod_iface decls
88 = do env <- initTcEnv hst (pcs_PTE pcs)
90 (maybe_result, (warns,errs)) <- initTc dflags env tc_module
92 let { maybe_tc_result :: Maybe TcResults ;
93 maybe_tc_result = case maybe_result of
95 Just (_,r) -> Just r }
97 printErrorsAndWarnings (errs,warns)
98 printTcDump dflags maybe_tc_result
100 if isEmptyBag errs then
101 return maybe_tc_result
105 tc_module :: TcM (RecTcEnv, TcResults)
106 tc_module = fixTc (\ ~(unf_env ,_) -> tcModule pcs hst get_fixity this_mod decls unf_env)
108 fixity_env = mi_fixities mod_iface
110 get_fixity :: Name -> Maybe Fixity
111 get_fixity nm = lookupNameEnv fixity_env nm
114 The internal monster:
116 tcModule :: PersistentCompilerState
118 -> (Name -> Maybe Fixity)
121 -> RecTcEnv -- The knot-tied environment
122 -> TcM (TcEnv, TcResults)
124 -- (unf_env :: RecTcEnv) is used for type-checking interface pragmas
125 -- which is done lazily [ie failure just drops the pragma
126 -- without having any global-failure effect].
128 -- unf_env is also used to get the pragama info
129 -- for imported dfuns and default methods
131 tcModule pcs hst get_fixity this_mod decls unf_env
132 = -- Type-check the type and class decls
133 tcTyAndClassDecls unf_env decls `thenTc` \ env ->
136 classes = tcEnvClasses env
137 tycons = tcEnvTyCons env -- INCLUDES tycons derived from classes
140 -- Typecheck the instance decls, includes deriving
141 tcInstDecls1 (pcs_insts pcs) (pcs_PRS pcs)
142 hst unf_env get_fixity this_mod
143 tycons decls `thenTc` \ (new_pcs_insts, inst_env, local_inst_info, deriv_binds) ->
144 tcSetInstEnv inst_env $
146 -- Default declarations
147 tcDefaults decls `thenTc` \ defaulting_tys ->
148 tcSetDefaultTys defaulting_tys $
150 -- Interface type signatures
151 -- We tie a knot so that the Ids read out of interfaces are in scope
152 -- when we read their pragmas.
153 -- What we rely on is that pragmas are typechecked lazily; if
154 -- any type errors are found (ie there's an inconsistency)
155 -- we silently discard the pragma
156 -- We must do this before mkImplicitDataBinds (which comes next), since
157 -- the latter looks up unpackCStringId, for example, which is usually
159 tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
160 tcExtendGlobalValEnv sig_ids $
162 -- Create any necessary record selector Ids and their bindings
163 -- "Necessary" includes data and newtype declarations
164 -- We don't create bindings for dictionary constructors;
165 -- they are always fully applied, and the bindings are just there
166 -- to support partial applications
167 mkImplicitDataBinds this_mod tycons `thenTc` \ (data_ids, imp_data_binds) ->
168 mkImplicitClassBinds this_mod classes `thenNF_Tc` \ (cls_ids, imp_cls_binds) ->
170 -- Extend the global value environment with
172 -- (b) record selectors
173 -- (c) class op selectors
174 -- (d) default-method ids... where? I can't see where these are
175 -- put into the envt, and I'm worried that the zonking phase
176 -- will find they aren't there and complain.
177 tcExtendGlobalValEnv data_ids $
178 tcExtendGlobalValEnv cls_ids $
179 tcGetEnv `thenTc` \ unf_env ->
181 -- Foreign import declarations next
182 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
183 tcExtendGlobalValEnv fo_ids $
185 -- Value declarations next.
186 -- We also typecheck any extra binds that came out of the "deriving" process
187 tcTopBinds (get_binds decls `ThenBinds` deriv_binds) `thenTc` \ ((val_binds, env), lie_valdecls) ->
190 -- Foreign export declarations next
191 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
193 -- Second pass over class and instance declarations,
194 -- to compile the bindings themselves.
195 tcInstDecls2 local_inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
196 tcClassDecls2 this_mod decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
197 tcRules (pcs_rules pcs) this_mod decls `thenNF_Tc` \ (new_pcs_rules, lie_rules, local_rules) ->
199 -- Deal with constant or ambiguous InstIds. How could
200 -- there be ambiguous ones? They can only arise if a
201 -- top-level decl falls under the monomorphism
202 -- restriction, and no subsequent decl instantiates its
203 -- type. (Usually, ambiguous type variables are resolved
204 -- during the generalisation step.)
206 lie_alldecls = lie_valdecls `plusLIE`
207 lie_instdecls `plusLIE`
208 lie_clasdecls `plusLIE`
209 lie_fodecls `plusLIE`
212 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
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 local_rules `thenNF_Tc` \ local_rules' ->
232 let (local_things, imported_things) = partition (isLocalThing this_mod)
233 (nameEnvElts (getTcGEnv final_env))
235 local_type_env :: TypeEnv
236 local_type_env = mkTypeEnv local_things
238 new_pte :: PackageTypeEnv
239 new_pte = extendTypeEnvList (pcs_PTE pcs) imported_things
241 final_pcs :: PersistentCompilerState
242 final_pcs = pcs { pcs_PTE = new_pte,
243 pcs_insts = new_pcs_insts,
244 pcs_rules = new_pcs_rules
248 TcResults { tc_pcs = final_pcs,
249 tc_env = local_type_env,
250 tc_binds = all_binds',
251 tc_insts = map iDFunId local_inst_info,
252 tc_fords = foi_decls ++ foe_decls',
253 tc_rules = local_rules'
257 get_binds decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
262 %************************************************************************
264 \subsection{Dumping output}
266 %************************************************************************
269 printTcDump dflags Nothing = return ()
270 printTcDump dflags (Just results)
271 = do dumpIfSet_dyn dflags Opt_D_dump_types
272 "Type signatures" (dump_sigs results)
273 dumpIfSet_dyn dflags Opt_D_dump_tc
274 "Typechecked" (dump_tc results)
277 = vcat [ppr (tc_binds results),
278 pp_rules (tc_rules results),
279 ppr_gen_tycons [tc | ATyCon tc <- nameEnvElts (tc_env results)]
282 dump_sigs results -- Print type signatures
283 = -- Convert to HsType so that we get source-language style printing
284 -- And sort by RdrName
285 vcat $ map ppr_sig $ sortLt lt_sig $
286 [ (toRdrName id, toHsType (idType id))
287 | AnId id <- nameEnvElts (tc_env results),
291 lt_sig (n1,_) (n2,_) = n1 < n2
292 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
294 want_sig id | opt_PprStyle_Debug = True
295 | otherwise = True -- For now
297 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
298 vcat (map ppr_gen_tycon tcs),
302 -- x&y are now Id's, not CoreExpr's
304 | Just ep <- tyConGenInfo tycon
305 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
307 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
310 = vcat [ ptext SLIT("Rep type:") <+> ppr (funResultTy from_tau),
311 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
312 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
315 (_,from_tau) = splitForAllTys (idType from)
318 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
319 nest 4 (vcat (map ppr rs)),