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, defaultDefaultTys )
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 -- use the default default settings, i.e. [Integer, Double]
116 tcSetDefaultTys defaultDefaultTys $
117 tcImports pcs hst get_fixity this_mod decls `thenTc` \ (env, new_pcs, local_inst_info, deriv_binds, local_rules) ->
118 ASSERT( null local_inst_info && nullBinds deriv_binds && null local_rules )
121 newTyVarTy openTypeKind `thenTc` \ ty ->
122 tcMonoExpr expr ty `thenTc` \ (expr', lie) ->
123 tcSimplifyTop lie `thenTc` \ binds ->
124 returnTc (new_pcs, mkHsLet binds expr')
126 get_fixity :: Name -> Maybe Fixity
127 get_fixity n = pprPanic "typecheckExpr" (ppr n)
130 typecheck :: DynFlags
131 -> PersistentCompilerState
133 -> PrintUnqualified -- For error printing
137 typecheck dflags pcs hst unqual thing_inside
138 = do { showPass dflags "Typechecker";
139 ; env <- initTcEnv hst (pcs_PTE pcs)
141 ; (maybe_tc_result, (warns,errs)) <- initTc dflags env thing_inside
143 ; printErrorsAndWarnings unqual (errs,warns)
145 ; if isEmptyBag errs then
146 return maybe_tc_result
152 The internal monster:
154 tcModule :: PersistentCompilerState
156 -> (Name -> Maybe Fixity)
159 -> TcM (PersistentCompilerState, TcResults)
161 tcModule pcs hst get_fixity this_mod decls
162 = -- Type-check the type and class decls, and all imported decls
163 tcImports pcs hst get_fixity this_mod decls `thenTc` \ (env, new_pcs, local_inst_info, deriv_binds, local_rules) ->
167 -- Foreign import declarations next
168 -- traceTc (text "Tc4") `thenNF_Tc_`
169 tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
170 tcExtendGlobalValEnv fo_ids $
172 -- Default declarations
173 tcDefaults decls `thenTc` \ defaulting_tys ->
174 tcSetDefaultTys defaulting_tys $
176 -- Value declarations next.
177 -- We also typecheck any extra binds that came out of the "deriving" process
178 -- traceTc (text "Tc5") `thenNF_Tc_`
179 tcTopBinds (val_binds `ThenBinds` deriv_binds) `thenTc` \ ((val_binds, env), lie_valdecls) ->
182 -- Foreign export declarations next
183 -- traceTc (text "Tc6") `thenNF_Tc_`
184 tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
186 -- Second pass over class and instance declarations,
187 -- to compile the bindings themselves.
188 tcInstDecls2 local_inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
189 tcClassDecls2 this_mod tycl_decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
190 tcSourceRules source_rules `thenNF_Tc` \ (lie_rules, more_local_rules) ->
192 -- Deal with constant or ambiguous InstIds. How could
193 -- there be ambiguous ones? They can only arise if a
194 -- top-level decl falls under the monomorphism
195 -- restriction, and no subsequent decl instantiates its
196 -- type. (Usually, ambiguous type variables are resolved
197 -- during the generalisation step.)
199 lie_alldecls = lie_valdecls `plusLIE`
200 lie_instdecls `plusLIE`
201 lie_clasdecls `plusLIE`
202 lie_fodecls `plusLIE`
205 tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
207 -- Backsubstitution. This must be done last.
208 -- Even tcSimplifyTop may do some unification.
210 all_binds = val_binds `AndMonoBinds`
211 inst_binds `AndMonoBinds`
212 cls_dm_binds `AndMonoBinds`
213 const_inst_binds `AndMonoBinds`
216 -- traceTc (text "Tc9") `thenNF_Tc_`
217 zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', final_env) ->
219 -- zonkTopBinds puts all the top-level Ids into the tcGEnv
220 zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
221 zonkRules more_local_rules `thenNF_Tc` \ more_local_rules' ->
224 let local_things = filter (isLocalThing this_mod) (nameEnvElts (getTcGEnv final_env))
226 -- Create any necessary "implicit" bindings (data constructors etc)
227 -- Should we create bindings for dictionary constructors?
228 -- They are always fully applied, and the bindings are just there
229 -- to support partial applications. But it's easier to let them through.
230 implicit_binds = andMonoBindList [ CoreMonoBind id (unfoldingTemplate unf)
231 | id <- implicitTyThingIds local_things
232 , let unf = idUnfolding id
236 local_type_env :: TypeEnv
237 local_type_env = mkTypeEnv local_things
239 all_local_rules = local_rules ++ more_local_rules'
241 -- traceTc (text "Tc10") `thenNF_Tc_`
243 TcResults { tc_env = local_type_env,
244 tc_binds = implicit_binds `AndMonoBinds` all_binds',
245 tc_insts = map iDFunId local_inst_info,
246 tc_fords = foi_decls ++ foe_decls',
247 tc_rules = all_local_rules
251 tycl_decls = [d | TyClD d <- decls]
252 val_binds = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
253 source_rules = [d | RuleD d <- decls, not (isIfaceRuleDecl d)]
258 tcImports :: PersistentCompilerState
260 -> (Name -> Maybe Fixity)
263 -> TcM (TcEnv, PersistentCompilerState,
264 [InstInfo], RenamedHsBinds, [TypecheckedRuleDecl])
266 -- tcImports is a slight mis-nomer.
267 -- It deals with everythign that could be an import:
268 -- type and class decls
269 -- interface signatures
272 -- These can occur in source code too, of course
274 tcImports pcs hst get_fixity this_mod decls
275 = fixTc (\ ~(unf_env, _, _, _, _) ->
276 -- (unf_env :: RecTcEnv) is used for type-checking interface pragmas
277 -- which is done lazily [ie failure just drops the pragma
278 -- without having any global-failure effect].
280 -- unf_env is also used to get the pragama info
281 -- for imported dfuns and default methods
283 -- traceTc (text "Tc1") `thenNF_Tc_`
284 tcTyAndClassDecls unf_env tycl_decls `thenTc` \ env ->
287 -- Typecheck the instance decls, includes deriving
288 -- traceTc (text "Tc2") `thenNF_Tc_`
289 tcInstDecls1 (pcs_insts pcs) (pcs_PRS pcs)
290 hst unf_env get_fixity this_mod
291 decls `thenTc` \ (new_pcs_insts, inst_env, local_inst_info, deriv_binds) ->
292 tcSetInstEnv inst_env $
294 -- Interface type signatures
295 -- We tie a knot so that the Ids read out of interfaces are in scope
296 -- when we read their pragmas.
297 -- What we rely on is that pragmas are typechecked lazily; if
298 -- any type errors are found (ie there's an inconsistency)
299 -- we silently discard the pragma
300 -- traceTc (text "Tc3") `thenNF_Tc_`
301 tcInterfaceSigs unf_env tycl_decls `thenTc` \ sig_ids ->
302 tcExtendGlobalValEnv sig_ids $
305 tcIfaceRules (pcs_rules pcs) this_mod iface_rules `thenNF_Tc` \ (new_pcs_rules, local_rules) ->
307 tcGetEnv `thenTc` \ unf_env ->
309 imported_things = filter (not . isLocalThing this_mod) (nameEnvElts (getTcGEnv unf_env))
311 new_pte :: PackageTypeEnv
312 new_pte = extendTypeEnvList (pcs_PTE pcs) imported_things
314 new_pcs :: PersistentCompilerState
315 new_pcs = pcs { pcs_PTE = new_pte,
316 pcs_insts = new_pcs_insts,
317 pcs_rules = new_pcs_rules
320 returnTc (unf_env, new_pcs, local_inst_info, deriv_binds, local_rules)
323 tycl_decls = [d | TyClD d <- decls]
324 iface_rules = [d | RuleD d <- decls, isIfaceRuleDecl d]
327 %************************************************************************
329 \subsection{Dumping output}
331 %************************************************************************
334 printTcDump dflags Nothing = return ()
335 printTcDump dflags (Just (_, results))
336 = do dumpIfSet_dyn dflags Opt_D_dump_types
337 "Type signatures" (dump_sigs results)
338 dumpIfSet_dyn dflags Opt_D_dump_tc
339 "Typechecked" (dump_tc results)
342 = vcat [ppr (tc_binds results),
343 pp_rules (tc_rules results),
344 ppr_gen_tycons [tc | ATyCon tc <- nameEnvElts (tc_env results)]
347 dump_sigs results -- Print type signatures
348 = -- Convert to HsType so that we get source-language style printing
349 -- And sort by RdrName
350 vcat $ map ppr_sig $ sortLt lt_sig $
351 [ (toRdrName id, toHsType (idType id))
352 | AnId id <- nameEnvElts (tc_env results),
356 lt_sig (n1,_) (n2,_) = n1 < n2
357 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
359 want_sig id | opt_PprStyle_Debug = True
360 | otherwise = True -- For now
362 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
363 vcat (map ppr_gen_tycon tcs),
367 -- x&y are now Id's, not CoreExpr's
369 | Just ep <- tyConGenInfo tycon
370 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
372 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
375 = vcat [ ptext SLIT("Rep type:") <+> ppr (funResultTy from_tau),
376 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
377 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
380 (_,from_tau) = splitForAllTys (idType from)
383 pp_rules rs = vcat [ptext SLIT("{-# RULES"),
384 nest 4 (vcat (map ppr rs)),