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
26 import TcType ( newTyVarTy )
27 import Inst ( plusLIE )
28 import TcBinds ( tcTopBinds )
29 import TcClassDcl ( tcClassDecls2 )
30 import TcDefaults ( tcDefaults )
31 import TcExpr ( tcMonoExpr )
32 import TcEnv ( TcEnv, InstInfo(iDFunId), tcExtendGlobalValEnv,
33 isLocalThing, tcSetEnv, tcSetInstEnv, initTcEnv, getTcGEnv
35 import TcRules ( tcIfaceRules, tcSourceRules )
36 import TcForeign ( tcForeignImports, tcForeignExports )
37 import TcIfaceSig ( tcInterfaceSigs )
38 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
39 import TcSimplify ( tcSimplifyTop )
40 import TcTyClsDecls ( tcTyAndClassDecls )
42 import CoreUnfold ( unfoldingTemplate, hasUnfolding )
43 import Type ( funResultTy, splitForAllTys, openTypeKind )
44 import Bag ( isEmptyBag )
45 import ErrUtils ( printErrorsAndWarnings, dumpIfSet_dyn, showPass )
46 import Id ( idType, idUnfolding )
47 import Module ( Module )
48 import Name ( Name, toRdrName )
49 import Name ( nameEnvElts, lookupNameEnv )
50 import TyCon ( tyConGenInfo )
52 import BasicTypes ( EP(..), Fixity )
53 import Bag ( isEmptyBag )
55 import HscTypes ( PersistentCompilerState(..), HomeSymbolTable,
56 PackageTypeEnv, DFunId, 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_insts :: [DFunId], -- Instances
72 tc_binds :: TypecheckedMonoBinds, -- Bindings
73 tc_fords :: [TypecheckedForeignDecl], -- Foreign import & exports.
74 tc_rules :: [TypecheckedRuleDecl] -- Transformation rules
80 -> PersistentCompilerState
82 -> ModIface -- Iface for this module
83 -> PrintUnqualified -- For error printing
85 -> IO (Maybe (PersistentCompilerState, TcResults))
86 -- The new PCS is Augmented with imported information,
87 -- (but not stuff from this module)
90 typecheckModule dflags pcs hst mod_iface unqual decls
91 = do { maybe_tc_result <- typecheck dflags pcs hst unqual $
92 tcModule pcs hst get_fixity this_mod decls
93 ; printTcDump dflags maybe_tc_result
94 ; return maybe_tc_result }
96 this_mod = mi_module mod_iface
97 fixity_env = mi_fixities mod_iface
99 get_fixity :: Name -> Maybe Fixity
100 get_fixity nm = lookupNameEnv fixity_env nm
103 typecheckExpr :: DynFlags
104 -> PersistentCompilerState
106 -> PrintUnqualified -- For error printing
108 -> (RenamedHsExpr, -- The expression itself
109 [RenamedHsDecl]) -- Plus extra decls it sucked in from interface files
110 -> IO (Maybe (PersistentCompilerState, TypecheckedHsExpr))
112 typecheckExpr dflags pcs hst unqual this_mod (expr, decls)
113 = typecheck dflags pcs hst unqual $
115 tcImports pcs hst get_fixity this_mod decls `thenTc` \ (env, new_pcs, local_inst_info, deriv_binds, local_rules) ->
116 ASSERT( null local_inst_info && nullBinds deriv_binds && null local_rules )
119 newTyVarTy openTypeKind `thenTc` \ ty ->
120 tcMonoExpr expr ty `thenTc` \ (expr', lie) ->
121 tcSimplifyTop lie `thenTc` \ binds ->
122 returnTc (new_pcs, mkHsLet binds expr')
124 get_fixity :: Name -> Maybe Fixity
125 get_fixity n = pprPanic "typecheckExpr" (ppr n)
128 typecheck :: DynFlags
129 -> PersistentCompilerState
131 -> PrintUnqualified -- For error printing
135 typecheck dflags pcs hst unqual thing_inside
136 = do { showPass dflags "Typechecker";
137 ; env <- initTcEnv hst (pcs_PTE pcs)
139 ; (maybe_tc_result, (warns,errs)) <- initTc dflags env thing_inside
141 ; printErrorsAndWarnings unqual (errs,warns)
143 ; if isEmptyBag errs then
144 return maybe_tc_result
150 The internal monster:
152 tcModule :: PersistentCompilerState
154 -> (Name -> Maybe Fixity)
157 -> TcM (PersistentCompilerState, TcResults)
159 tcModule pcs hst get_fixity this_mod decls
160 = -- Type-check the type and class decls, and all imported decls
161 tcImports pcs hst get_fixity this_mod decls `thenTc` \ (env, new_pcs, local_inst_info, deriv_binds, local_rules) ->
165 -- Foreign import declarations next
166 -- traceTc (text "Tc4") `thenNF_Tc_`
167 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
168 tcExtendGlobalValEnv fo_ids $
170 -- Default declarations
171 tcDefaults decls `thenTc` \ defaulting_tys ->
172 tcSetDefaultTys defaulting_tys $
174 -- Value declarations next.
175 -- We also typecheck any extra binds that came out of the "deriving" process
176 -- traceTc (text "Tc5") `thenNF_Tc_`
177 tcTopBinds (val_binds `ThenBinds` deriv_binds) `thenTc` \ ((val_binds, env), lie_valdecls) ->
180 -- Foreign export declarations next
181 -- traceTc (text "Tc6") `thenNF_Tc_`
182 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
184 -- Second pass over class and instance declarations,
185 -- to compile the bindings themselves.
186 tcInstDecls2 local_inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
187 tcClassDecls2 this_mod tycl_decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
188 tcSourceRules source_rules `thenNF_Tc` \ (lie_rules, more_local_rules) ->
190 -- Deal with constant or ambiguous InstIds. How could
191 -- there be ambiguous ones? They can only arise if a
192 -- top-level decl falls under the monomorphism
193 -- restriction, and no subsequent decl instantiates its
194 -- type. (Usually, ambiguous type variables are resolved
195 -- during the generalisation step.)
197 lie_alldecls = lie_valdecls `plusLIE`
198 lie_instdecls `plusLIE`
199 lie_clasdecls `plusLIE`
200 lie_fodecls `plusLIE`
203 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
205 -- Backsubstitution. This must be done last.
206 -- Even tcSimplifyTop may do some unification.
208 all_binds = val_binds `AndMonoBinds`
209 inst_binds `AndMonoBinds`
210 cls_dm_binds `AndMonoBinds`
211 const_inst_binds `AndMonoBinds`
214 -- traceTc (text "Tc9") `thenNF_Tc_`
215 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', final_env) ->
217 -- zonkTopBinds puts all the top-level Ids into the tcGEnv
218 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
219 zonkRules more_local_rules `thenNF_Tc` \ more_local_rules' ->
222 let local_things = filter (isLocalThing this_mod) (nameEnvElts (getTcGEnv final_env))
224 -- Create any necessary "implicit" bindings (data constructors etc)
225 -- Should we create bindings for dictionary constructors?
226 -- They are always fully applied, and the bindings are just there
227 -- to support partial applications. But it's easier to let them through.
228 implicit_binds = andMonoBindList [ CoreMonoBind id (unfoldingTemplate unf)
229 | id <- implicitTyThingIds local_things
230 , let unf = idUnfolding id
234 local_type_env :: TypeEnv
235 local_type_env = mkTypeEnv local_things
237 all_local_rules = local_rules ++ more_local_rules'
239 -- traceTc (text "Tc10") `thenNF_Tc_`
241 TcResults { tc_env = local_type_env,
242 tc_binds = implicit_binds `AndMonoBinds` all_binds',
243 tc_insts = map iDFunId local_inst_info,
244 tc_fords = foi_decls ++ foe_decls',
245 tc_rules = all_local_rules
249 tycl_decls = [d | TyClD d <- decls]
250 val_binds = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
251 source_rules = [d | RuleD d <- decls, not (isIfaceRuleDecl d)]
256 tcImports :: PersistentCompilerState
258 -> (Name -> Maybe Fixity)
261 -> TcM (TcEnv, PersistentCompilerState,
262 [InstInfo], RenamedHsBinds, [TypecheckedRuleDecl])
264 -- tcImports is a slight mis-nomer.
265 -- It deals with everythign that could be an import:
266 -- type and class decls
267 -- interface signatures
270 -- These can occur in source code too, of course
272 tcImports pcs hst get_fixity this_mod decls
273 = fixTc (\ ~(unf_env, _, _, _, _) ->
274 -- (unf_env :: RecTcEnv) is used for type-checking interface pragmas
275 -- which is done lazily [ie failure just drops the pragma
276 -- without having any global-failure effect].
278 -- unf_env is also used to get the pragama info
279 -- for imported dfuns and default methods
281 -- traceTc (text "Tc1") `thenNF_Tc_`
282 tcTyAndClassDecls unf_env tycl_decls `thenTc` \ env ->
285 -- Typecheck the instance decls, includes deriving
286 -- traceTc (text "Tc2") `thenNF_Tc_`
287 tcInstDecls1 (pcs_insts pcs) (pcs_PRS pcs)
288 hst unf_env get_fixity this_mod
289 decls `thenTc` \ (new_pcs_insts, inst_env, local_inst_info, deriv_binds) ->
290 tcSetInstEnv inst_env $
292 -- Interface type signatures
293 -- We tie a knot so that the Ids read out of interfaces are in scope
294 -- when we read their pragmas.
295 -- What we rely on is that pragmas are typechecked lazily; if
296 -- any type errors are found (ie there's an inconsistency)
297 -- we silently discard the pragma
298 -- traceTc (text "Tc3") `thenNF_Tc_`
299 tcInterfaceSigs unf_env tycl_decls `thenTc` \ sig_ids ->
300 tcExtendGlobalValEnv sig_ids $
303 tcIfaceRules (pcs_rules pcs) this_mod iface_rules `thenNF_Tc` \ (new_pcs_rules, local_rules) ->
305 tcGetEnv `thenTc` \ unf_env ->
307 imported_things = filter (not . isLocalThing this_mod) (nameEnvElts (getTcGEnv unf_env))
309 new_pte :: PackageTypeEnv
310 new_pte = extendTypeEnvList (pcs_PTE pcs) imported_things
312 new_pcs :: PersistentCompilerState
313 new_pcs = pcs { pcs_PTE = new_pte,
314 pcs_insts = new_pcs_insts,
315 pcs_rules = new_pcs_rules
318 returnTc (unf_env, new_pcs, local_inst_info, deriv_binds, local_rules)
321 tycl_decls = [d | TyClD d <- decls]
322 iface_rules = [d | RuleD d <- decls, isIfaceRuleDecl d]
325 %************************************************************************
327 \subsection{Dumping output}
329 %************************************************************************
332 printTcDump dflags Nothing = return ()
333 printTcDump dflags (Just (_, results))
334 = do dumpIfSet_dyn dflags Opt_D_dump_types
335 "Type signatures" (dump_sigs results)
336 dumpIfSet_dyn dflags Opt_D_dump_tc
337 "Typechecked" (dump_tc results)
340 = vcat [ppr (tc_binds results),
341 pp_rules (tc_rules results),
342 ppr_gen_tycons [tc | ATyCon tc <- nameEnvElts (tc_env results)]
345 dump_sigs results -- Print type signatures
346 = -- Convert to HsType so that we get source-language style printing
347 -- And sort by RdrName
348 vcat $ map ppr_sig $ sortLt lt_sig $
349 [ (toRdrName id, toHsType (idType id))
350 | AnId id <- nameEnvElts (tc_env results),
354 lt_sig (n1,_) (n2,_) = n1 < n2
355 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
357 want_sig id | opt_PprStyle_Debug = True
358 | otherwise = True -- For now
360 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
361 vcat (map ppr_gen_tycon tcs),
365 -- x&y are now Id's, not CoreExpr's
367 | Just ep <- tyConGenInfo tycon
368 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
370 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
373 = vcat [ ptext SLIT("Rep type:") <+> ppr (funResultTy from_tau),
374 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
375 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
378 (_,from_tau) = splitForAllTys (idType from)
381 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
382 nest 4 (vcat (map ppr rs)),