2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
8 typecheckModule, typecheckExpr, TcResults(..)
11 #include "HsVersions.h"
13 import CmdLineOpts ( DynFlag(..), DynFlags, opt_PprStyle_Debug )
14 import HsSyn ( HsBinds(..), MonoBinds(..), HsDecl(..),
15 isIfaceRuleDecl, nullBinds, andMonoBindList
17 import HsTypes ( toHsType )
18 import RnHsSyn ( RenamedHsBinds, RenamedHsDecl, RenamedHsExpr )
19 import TcHsSyn ( TypecheckedMonoBinds, TypecheckedHsExpr,
20 TypecheckedForeignDecl, TypecheckedRuleDecl,
21 zonkTopBinds, zonkForeignExports, zonkRules, mkHsLet,
27 import TcType ( newTyVarTy, zonkTcType )
28 import Inst ( plusLIE )
29 import TcBinds ( tcTopBinds )
30 import TcClassDcl ( tcClassDecls2 )
31 import TcDefaults ( tcDefaults, defaultDefaultTys )
32 import TcExpr ( tcMonoExpr )
33 import TcEnv ( TcEnv, InstInfo, tcExtendGlobalValEnv,
34 isLocalThing, tcSetEnv, tcSetInstEnv, initTcEnv, getTcGEnv
36 import TcRules ( tcIfaceRules, tcSourceRules )
37 import TcForeign ( tcForeignImports, tcForeignExports )
38 import TcIfaceSig ( tcInterfaceSigs )
39 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
40 import TcSimplify ( tcSimplifyTop )
41 import TcTyClsDecls ( tcTyAndClassDecls )
43 import CoreUnfold ( unfoldingTemplate, hasUnfolding )
44 import Type ( funResultTy, splitForAllTys, openTypeKind )
45 import Bag ( isEmptyBag )
46 import ErrUtils ( printErrorsAndWarnings, errorsFound, dumpIfSet_dyn, showPass )
47 import Id ( idType, idUnfolding )
48 import Module ( Module )
49 import Name ( Name, toRdrName )
50 import Name ( nameEnvElts, lookupNameEnv )
51 import TyCon ( tyConGenInfo )
53 import BasicTypes ( EP(..), Fixity )
55 import HscTypes ( PersistentCompilerState(..), HomeSymbolTable,
56 PackageTypeEnv, ModIface(..),
57 TypeEnv, extendTypeEnvList,
58 TyThing(..), implicitTyThingIds,
63 Outside-world interface:
66 -- Convenient type synonyms first:
69 -- All these fields have info *just for this module*
70 tc_env :: TypeEnv, -- The top level TypeEnv
71 tc_binds :: TypecheckedMonoBinds, -- Bindings
72 tc_fords :: [TypecheckedForeignDecl], -- Foreign import & exports.
73 tc_rules :: [TypecheckedRuleDecl] -- Transformation rules
79 -> PersistentCompilerState
81 -> ModIface -- Iface for this module
82 -> PrintUnqualified -- For error printing
84 -> IO (Maybe (PersistentCompilerState, TcResults))
85 -- The new PCS is Augmented with imported information,
86 -- (but not stuff from this module)
89 typecheckModule dflags pcs hst mod_iface unqual decls
90 = do { maybe_tc_result <- typecheck dflags pcs hst unqual $
91 tcModule pcs hst get_fixity this_mod decls
92 ; printTcDump dflags maybe_tc_result
93 ; return maybe_tc_result }
95 this_mod = mi_module mod_iface
96 fixity_env = mi_fixities mod_iface
98 get_fixity :: Name -> Maybe Fixity
99 get_fixity nm = lookupNameEnv fixity_env nm
102 typecheckExpr :: DynFlags
103 -> PersistentCompilerState
105 -> PrintUnqualified -- For error printing
107 -> (RenamedHsExpr, -- The expression itself
108 [RenamedHsDecl]) -- Plus extra decls it sucked in from interface files
109 -> IO (Maybe (PersistentCompilerState, TypecheckedHsExpr, TcType))
111 typecheckExpr dflags pcs hst unqual this_mod (expr, decls)
112 = typecheck dflags pcs hst unqual $
114 -- use the default default settings, i.e. [Integer, Double]
115 tcSetDefaultTys defaultDefaultTys $
116 tcImports pcs hst get_fixity this_mod decls `thenTc` \ (env, new_pcs, local_inst_info, deriv_binds, local_rules) ->
117 ASSERT( null local_inst_info && nullBinds deriv_binds && null local_rules )
120 newTyVarTy openTypeKind `thenTc` \ ty ->
121 tcMonoExpr expr ty `thenTc` \ (expr', lie) ->
122 tcSimplifyTop lie `thenTc` \ binds ->
123 let all_expr = mkHsLet binds expr' in
124 zonkExpr all_expr `thenNF_Tc` \ zonked_expr ->
125 zonkTcType ty `thenNF_Tc` \ zonked_ty ->
126 returnTc (new_pcs, zonked_expr, zonked_ty)
128 get_fixity :: Name -> Maybe Fixity
129 get_fixity n = pprPanic "typecheckExpr" (ppr n)
132 typecheck :: DynFlags
133 -> PersistentCompilerState
135 -> PrintUnqualified -- For error printing
139 typecheck dflags pcs hst unqual thing_inside
140 = do { showPass dflags "Typechecker";
141 ; env <- initTcEnv hst (pcs_PTE pcs)
143 ; (maybe_tc_result, errs) <- initTc dflags env thing_inside
145 ; printErrorsAndWarnings unqual errs
147 ; if errorsFound errs then
150 return maybe_tc_result
154 The internal monster:
156 tcModule :: PersistentCompilerState
158 -> (Name -> Maybe Fixity)
161 -> TcM (PersistentCompilerState, TcResults)
163 tcModule pcs hst get_fixity this_mod decls
164 = -- Type-check the type and class decls, and all imported decls
165 tcImports pcs hst get_fixity this_mod decls `thenTc` \ (env, new_pcs, local_inst_info, deriv_binds, local_rules) ->
169 -- Foreign import declarations next
170 -- traceTc (text "Tc4") `thenNF_Tc_`
171 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
172 tcExtendGlobalValEnv fo_ids $
174 -- Default declarations
175 tcDefaults decls `thenTc` \ defaulting_tys ->
176 tcSetDefaultTys defaulting_tys $
178 -- Value declarations next.
179 -- We also typecheck any extra binds that came out of the "deriving" process
180 -- traceTc (text "Tc5") `thenNF_Tc_`
181 tcTopBinds (val_binds `ThenBinds` deriv_binds) `thenTc` \ ((val_binds, env), lie_valdecls) ->
184 -- Foreign export declarations next
185 -- traceTc (text "Tc6") `thenNF_Tc_`
186 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
188 -- Second pass over class and instance declarations,
189 -- to compile the bindings themselves.
190 tcInstDecls2 local_inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
191 tcClassDecls2 this_mod tycl_decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
192 tcSourceRules source_rules `thenNF_Tc` \ (lie_rules, more_local_rules) ->
194 -- Deal with constant or ambiguous InstIds. How could
195 -- there be ambiguous ones? They can only arise if a
196 -- top-level decl falls under the monomorphism
197 -- restriction, and no subsequent decl instantiates its
198 -- type. (Usually, ambiguous type variables are resolved
199 -- during the generalisation step.)
201 lie_alldecls = lie_valdecls `plusLIE`
202 lie_instdecls `plusLIE`
203 lie_clasdecls `plusLIE`
204 lie_fodecls `plusLIE`
207 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
209 -- Backsubstitution. This must be done last.
210 -- Even tcSimplifyTop may do some unification.
212 all_binds = val_binds `AndMonoBinds`
213 inst_binds `AndMonoBinds`
214 cls_dm_binds `AndMonoBinds`
215 const_inst_binds `AndMonoBinds`
218 -- traceTc (text "Tc9") `thenNF_Tc_`
219 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', final_env) ->
221 -- zonkTopBinds puts all the top-level Ids into the tcGEnv
222 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
223 zonkRules more_local_rules `thenNF_Tc` \ more_local_rules' ->
226 let local_things = filter (isLocalThing this_mod) (nameEnvElts (getTcGEnv final_env))
228 -- Create any necessary "implicit" bindings (data constructors etc)
229 -- Should we create bindings for dictionary constructors?
230 -- They are always fully applied, and the bindings are just there
231 -- to support partial applications. But it's easier to let them through.
232 implicit_binds = andMonoBindList [ CoreMonoBind id (unfoldingTemplate unf)
233 | id <- implicitTyThingIds local_things
234 , let unf = idUnfolding id
238 local_type_env :: TypeEnv
239 local_type_env = mkTypeEnv local_things
241 all_local_rules = local_rules ++ more_local_rules'
243 -- traceTc (text "Tc10") `thenNF_Tc_`
245 TcResults { tc_env = local_type_env,
246 tc_binds = implicit_binds `AndMonoBinds` all_binds',
247 tc_fords = foi_decls ++ foe_decls',
248 tc_rules = all_local_rules
252 tycl_decls = [d | TyClD d <- decls]
253 val_binds = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
254 source_rules = [d | RuleD d <- decls, not (isIfaceRuleDecl d)]
259 tcImports :: PersistentCompilerState
261 -> (Name -> Maybe Fixity)
264 -> TcM (TcEnv, PersistentCompilerState,
265 [InstInfo], RenamedHsBinds, [TypecheckedRuleDecl])
267 -- tcImports is a slight mis-nomer.
268 -- It deals with everythign that could be an import:
269 -- type and class decls
270 -- interface signatures
273 -- These can occur in source code too, of course
275 tcImports pcs hst get_fixity this_mod decls
276 = fixTc (\ ~(unf_env, _, _, _, _) ->
277 -- (unf_env :: RecTcEnv) is used for type-checking interface pragmas
278 -- which is done lazily [ie failure just drops the pragma
279 -- without having any global-failure effect].
281 -- unf_env is also used to get the pragama info
282 -- for imported dfuns and default methods
284 -- traceTc (text "Tc1") `thenNF_Tc_`
285 tcTyAndClassDecls unf_env tycl_decls `thenTc` \ env ->
288 -- Typecheck the instance decls, includes deriving
289 -- traceTc (text "Tc2") `thenNF_Tc_`
290 tcInstDecls1 (pcs_insts pcs) (pcs_PRS pcs)
291 hst unf_env get_fixity this_mod
292 decls `thenTc` \ (new_pcs_insts, inst_env, local_inst_info, deriv_binds) ->
293 tcSetInstEnv inst_env $
295 -- Interface type signatures
296 -- We tie a knot so that the Ids read out of interfaces are in scope
297 -- when we read their pragmas.
298 -- What we rely on is that pragmas are typechecked lazily; if
299 -- any type errors are found (ie there's an inconsistency)
300 -- we silently discard the pragma
301 -- traceTc (text "Tc3") `thenNF_Tc_`
302 tcInterfaceSigs unf_env tycl_decls `thenTc` \ sig_ids ->
303 tcExtendGlobalValEnv sig_ids $
306 tcIfaceRules (pcs_rules pcs) this_mod iface_rules `thenNF_Tc` \ (new_pcs_rules, local_rules) ->
308 tcGetEnv `thenTc` \ unf_env ->
310 imported_things = filter (not . isLocalThing this_mod) (nameEnvElts (getTcGEnv unf_env))
312 new_pte :: PackageTypeEnv
313 new_pte = extendTypeEnvList (pcs_PTE pcs) imported_things
315 new_pcs :: PersistentCompilerState
316 new_pcs = pcs { pcs_PTE = new_pte,
317 pcs_insts = new_pcs_insts,
318 pcs_rules = new_pcs_rules
321 returnTc (unf_env, new_pcs, local_inst_info, deriv_binds, local_rules)
324 tycl_decls = [d | TyClD d <- decls]
325 iface_rules = [d | RuleD d <- decls, isIfaceRuleDecl d]
328 %************************************************************************
330 \subsection{Dumping output}
332 %************************************************************************
335 printTcDump dflags Nothing = return ()
336 printTcDump dflags (Just (_, results))
337 = do dumpIfSet_dyn dflags Opt_D_dump_types
338 "Type signatures" (dump_sigs results)
339 dumpIfSet_dyn dflags Opt_D_dump_tc
340 "Typechecked" (dump_tc results)
343 = vcat [ppr (tc_binds results),
344 pp_rules (tc_rules results),
345 ppr_gen_tycons [tc | ATyCon tc <- nameEnvElts (tc_env results)]
348 dump_sigs results -- Print type signatures
349 = -- Convert to HsType so that we get source-language style printing
350 -- And sort by RdrName
351 vcat $ map ppr_sig $ sortLt lt_sig $
352 [ (toRdrName id, toHsType (idType id))
353 | AnId id <- nameEnvElts (tc_env results),
357 lt_sig (n1,_) (n2,_) = n1 < n2
358 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
360 want_sig id | opt_PprStyle_Debug = True
361 | otherwise = True -- For now
363 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
364 vcat (map ppr_gen_tycon tcs),
368 -- x&y are now Id's, not CoreExpr's
370 | Just ep <- tyConGenInfo tycon
371 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
373 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
376 = vcat [ ptext SLIT("Rep type:") <+> ppr (funResultTy from_tau),
377 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
378 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
381 (_,from_tau) = splitForAllTys (idType from)
384 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
385 nest 4 (vcat (map ppr rs)),