2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
5 \section[TcModule]{Typechecking a whole module}
10 tcRnStmt, tcRnExpr, tcRnType,
22 #include "HsVersions.h"
26 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
88 import {- Kind parts of -} Type
97 import Control.Monad ( unless )
98 import Data.Maybe ( isJust )
103 %************************************************************************
105 Typecheck and rename a module
107 %************************************************************************
113 -> Bool -- True <=> save renamed syntax
114 -> Located (HsModule RdrName)
115 -> IO (Messages, Maybe TcGblEnv)
117 tcRnModule hsc_env hsc_src save_rn_syntax
118 (L loc (HsModule maybe_mod export_ies
119 import_decls local_decls mod_deprec _ module_info maybe_doc))
120 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
122 let { this_pkg = thisPackage (hsc_dflags hsc_env) ;
123 this_mod = case maybe_mod of
124 Nothing -> mAIN -- 'module M where' is omitted
125 Just (L _ mod) -> mkModule this_pkg mod } ;
128 initTc hsc_env hsc_src this_mod $
131 -- Deal with imports;
132 (rn_imports, rdr_env, imports) <- rnImports import_decls ;
134 let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)
135 ; dep_mods = imp_dep_mods imports
137 -- We want instance declarations from all home-package
138 -- modules below this one, including boot modules, except
139 -- ourselves. The 'except ourselves' is so that we don't
140 -- get the instances from this module's hs-boot file
141 ; want_instances :: ModuleName -> Bool
142 ; want_instances mod = mod `elemUFM` dep_mods
143 && mod /= moduleName this_mod
144 ; home_insts = hptInstances hsc_env want_instances
147 -- Record boot-file info in the EPS, so that it's
148 -- visible to loadHiBootInterface in tcRnSrcDecls,
149 -- and any other incrementally-performed imports
150 updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
152 -- Update the gbl env
154 gbl { tcg_rdr_env = plusOccEnv (tcg_rdr_env gbl) rdr_env,
155 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts,
156 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
157 tcg_rn_imports = if save_rn_syntax then
161 tcg_rn_decls = if save_rn_syntax then
167 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
168 -- Fail if there are any errors so far
169 -- The error printing (if needed) takes advantage
170 -- of the tcg_env we have now set
171 traceIf (text "rdr_env: " <+> ppr rdr_env) ;
174 -- Load any orphan-module and family instance-module
175 -- interfaces, so that their rules and instance decls will be
177 loadOrphanModules (imp_orphs imports) False ;
178 loadOrphanModules (imp_finsts imports) True ;
180 traceRn (text "rn1: checking family instance consistency") ;
181 let { directlyImpMods = map (\(mod, _, _) -> mod)
185 checkFamInstConsistency (imp_finsts imports) directlyImpMods ;
187 traceRn (text "rn1a") ;
188 -- Rename and type check the declarations
189 tcg_env <- if isHsBoot hsc_src then
190 tcRnHsBootDecls local_decls
192 tcRnSrcDecls local_decls ;
193 setGblEnv tcg_env $ do {
195 failIfErrsM ; -- reportDeprecations crashes sometimes
196 -- as a result of typechecker repairs (e.g. unboundNames)
197 traceRn (text "rn3") ;
199 -- Report the use of any deprecated things
200 -- We do this before processsing the export list so
201 -- that we don't bleat about re-exporting a deprecated
202 -- thing (especially via 'module Foo' export item)
203 -- Only uses in the body of the module are complained about
204 reportDeprecations (hsc_dflags hsc_env) tcg_env ;
206 -- Process the export list
207 (rn_exports, exports) <- rnExports (isJust maybe_mod) export_ies ;
209 traceRn (text "rn4") ;
211 -- Rename the Haddock documentation header
212 rn_module_doc <- rnMbHsDoc maybe_doc ;
214 -- Rename the Haddock module info
215 rn_description <- rnMbHsDoc (hmi_description module_info) ;
216 let { rn_module_info = module_info { hmi_description = rn_description } } ;
218 -- Check whether the entire module is deprecated
219 -- This happens only once per module
220 let { mod_deprecs = checkModDeprec mod_deprec } ;
222 -- Add exports and deprecations to envt
223 let { final_env = tcg_env { tcg_exports = exports,
224 tcg_rn_exports = if save_rn_syntax then
227 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly (availsToNameSet exports),
228 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
230 tcg_doc = rn_module_doc,
231 tcg_hmi = rn_module_info
233 -- A module deprecation over-rides the earlier ones
236 -- Report unused names
237 reportUnusedNames export_ies final_env ;
239 -- Dump output and return
246 %************************************************************************
248 Type-checking external-core modules
250 %************************************************************************
253 tcRnExtCore :: HscEnv
255 -> IO (Messages, Maybe ModGuts)
256 -- Nothing => some error occurred
258 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
259 -- The decls are IfaceDecls; all names are original names
260 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
262 initTc hsc_env ExtCoreFile this_mod $ do {
264 let { ldecls = map noLoc decls } ;
266 -- Deal with the type declarations; first bring their stuff
267 -- into scope, then rname them, then type check them
268 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
270 setGblEnv tcg_env $ do {
272 rn_decls <- rnTyClDecls ldecls ;
275 -- Dump trace of renaming part
276 rnDump (ppr rn_decls) ;
278 -- Typecheck them all together so that
279 -- any mutually recursive types are done right
280 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
281 -- Make the new type env available to stuff slurped from interface files
283 setGblEnv tcg_env $ do {
285 -- Now the core bindings
286 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
290 bndrs = bindersOfBinds core_binds ;
291 my_exports = map (Avail . idName) bndrs ;
292 -- ToDo: export the data types also?
294 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
296 mod_guts = ModGuts { mg_module = this_mod,
298 mg_usages = [], -- ToDo: compute usage
299 mg_dir_imps = [], -- ??
300 mg_deps = noDependencies, -- ??
301 mg_exports = my_exports,
302 mg_types = final_type_env,
303 mg_insts = tcg_insts tcg_env,
304 mg_fam_insts = tcg_fam_insts tcg_env,
306 mg_binds = core_binds,
309 mg_rdr_env = emptyGlobalRdrEnv,
310 mg_fix_env = emptyFixityEnv,
311 mg_deprecs = NoDeprecs,
312 mg_foreign = NoStubs,
313 mg_hpc_info = noHpcInfo,
314 mg_dbg_sites = noDbgSites
317 tcCoreDump mod_guts ;
322 mkFakeGroup decls -- Rather clumsy; lots of unused fields
323 = emptyRdrGroup { hs_tyclds = decls }
327 %************************************************************************
329 Type-checking the top level of a module
331 %************************************************************************
334 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
335 -- Returns the variables free in the decls
336 -- Reason: solely to report unused imports and bindings
338 = do { -- Load the hi-boot interface for this module, if any
339 -- We do this now so that the boot_names can be passed
340 -- to tcTyAndClassDecls, because the boot_names are
341 -- automatically considered to be loop breakers
343 boot_iface <- tcHiBootIface mod ;
345 -- Do all the declarations
346 (tc_envs, lie) <- getLIE $ tc_rn_src_decls boot_iface decls ;
348 -- Finish simplifying class constraints
350 -- tcSimplifyTop deals with constant or ambiguous InstIds.
351 -- How could there be ambiguous ones? They can only arise if a
352 -- top-level decl falls under the monomorphism restriction
353 -- and no subsequent decl instantiates its type.
355 -- We do this after checkMain, so that we use the type info
356 -- thaat checkMain adds
358 -- We do it with both global and local env in scope:
359 -- * the global env exposes the instances to tcSimplifyTop
360 -- * the local env exposes the local Ids to tcSimplifyTop,
361 -- so that we get better error messages (monomorphism restriction)
362 traceTc (text "Tc8") ;
363 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
365 -- Backsubstitution. This must be done last.
366 -- Even tcSimplifyTop may do some unification.
367 traceTc (text "Tc9") ;
368 let { (tcg_env, _) = tc_envs
369 ; TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
370 tcg_rules = rules, tcg_fords = fords } = tcg_env
371 ; all_binds = binds `unionBags` inst_binds } ;
373 (bind_ids, binds', fords', rules') <- zonkTopDecls all_binds rules fords ;
375 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
376 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
379 tcg_fords = fords' } } ;
381 -- Make the new type env available to stuff slurped from interface files
382 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
384 -- Compare the hi-boot iface (if any) with the real thing
385 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
387 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
390 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
391 -- Loops around dealing with each top level inter-splice group
392 -- in turn, until it's dealt with the entire module
393 tc_rn_src_decls boot_details ds
394 = do { let { (first_group, group_tail) = findSplice ds } ;
395 -- If ds is [] we get ([], Nothing)
397 -- Deal with decls up to, but not including, the first splice
398 (tcg_env, rn_decls) <- checkNoErrs $ rnTopSrcDecls first_group ;
399 -- checkNoErrs: don't typecheck if renaming failed
400 tc_envs <- setGblEnv tcg_env $
401 tcTopSrcDecls boot_details rn_decls ;
403 -- If there is no splice, we're nearly done
406 Nothing -> do { tcg_env <- checkMain ; -- Check for `main'
407 return (tcg_env, snd tc_envs)
410 -- If there's a splice, we must carry on
411 Just (SpliceDecl splice_expr, rest_ds) -> do {
413 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
416 -- Rename the splice expression, and get its supporting decls
417 (rn_splice_expr, splice_fvs) <- checkNoErrs (rnLExpr splice_expr) ;
418 -- checkNoErrs: don't typecheck if renaming failed
419 rnDump (ppr rn_splice_expr) ;
421 -- Execute the splice
422 spliced_decls <- tcSpliceDecls rn_splice_expr ;
424 -- Glue them on the front of the remaining decls and loop
425 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
426 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
431 %************************************************************************
433 Compiling hs-boot source files, and
434 comparing the hi-boot interface with the real thing
436 %************************************************************************
439 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
440 tcRnHsBootDecls decls
441 = do { let { (first_group, group_tail) = findSplice decls }
444 Just stuff -> spliceInHsBootErr stuff
447 -- Rename the declarations
448 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
449 ; setGblEnv tcg_env $ do {
451 -- Todo: check no foreign decls, no rules, no default decls
453 -- Typecheck type/class decls
454 ; traceTc (text "Tc2")
455 ; let tycl_decls = hs_tyclds rn_group
456 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
457 ; setGblEnv tcg_env $ do {
459 -- Typecheck instance decls
460 ; traceTc (text "Tc3")
461 ; (tcg_env, inst_infos, _binds)
462 <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group)
463 ; setGblEnv tcg_env $ do {
465 -- Typecheck value declarations
466 ; traceTc (text "Tc5")
467 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
470 -- No simplification or zonking to do
471 ; traceTc (text "Tc7a")
472 ; gbl_env <- getGblEnv
474 -- Make the final type-env
475 -- Include the dfun_ids so that their type sigs
476 -- are written into the interface file
477 ; let { type_env0 = tcg_type_env gbl_env
478 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
479 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
480 ; dfun_ids = map iDFunId inst_infos }
481 ; return (gbl_env { tcg_type_env = type_env2 })
484 spliceInHsBootErr (SpliceDecl (L loc _), _)
485 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
488 Once we've typechecked the body of the module, we want to compare what
489 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
492 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
493 -- Compare the hi-boot file for this module (if there is one)
494 -- with the type environment we've just come up with
495 -- In the common case where there is no hi-boot file, the list
496 -- of boot_names is empty.
498 -- The bindings we return give bindings for the dfuns defined in the
499 -- hs-boot file, such as $fbEqT = $fEqT
502 (TcGblEnv { tcg_insts = local_insts, tcg_fam_insts = local_fam_insts,
503 tcg_type_env = local_type_env })
504 (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts,
505 md_types = boot_type_env })
506 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts)) ;
507 ; mapM_ check_one (typeEnvElts boot_type_env)
508 ; dfun_binds <- mapM check_inst boot_insts
509 ; unless (null boot_fam_insts) $
510 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
511 "instances in boot files yet...")
512 -- FIXME: Why? The actual comparison is not hard, but what would
513 -- be the equivalent to the dfun bindings returned for class
514 -- instances? We can't easily equate tycons...
515 ; return (unionManyBags dfun_binds) }
518 | isImplicitTyThing boot_thing = return ()
519 | name `elem` dfun_names = return ()
520 | isWiredInName name = return () -- No checking for wired-in names. In particular,
521 -- 'error' is handled by a rather gross hack
522 -- (see comments in GHC.Err.hs-boot)
523 | Just real_thing <- lookupTypeEnv local_type_env name
524 = do { let boot_decl = tyThingToIfaceDecl boot_thing
525 real_decl = tyThingToIfaceDecl real_thing
526 ; checkTc (checkBootDecl boot_decl real_decl)
527 (bootMisMatch boot_thing boot_decl real_decl) }
528 -- The easiest way to check compatibility is to convert to
529 -- iface syntax, where we already have good comparison functions
531 = addErrTc (missingBootThing boot_thing)
533 name = getName boot_thing
535 dfun_names = map getName boot_insts
538 = case [dfun | inst <- local_insts,
539 let dfun = instanceDFunId inst,
540 idType dfun `tcEqType` boot_inst_ty ] of
541 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
542 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
544 boot_dfun = instanceDFunId boot_inst
545 boot_inst_ty = idType boot_dfun
546 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
549 missingBootThing thing
550 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
551 bootMisMatch thing boot_decl real_decl
552 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
553 ptext SLIT("Decl") <+> ppr real_decl,
554 ptext SLIT("Boot file:") <+> ppr boot_decl]
557 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
561 %************************************************************************
563 Type-checking the top level of a module
565 %************************************************************************
567 tcRnGroup takes a bunch of top-level source-code declarations, and
569 * gets supporting declarations from interface files
572 * and augments the TcGblEnv with the results
574 In Template Haskell it may be called repeatedly for each group of
575 declarations. It expects there to be an incoming TcGblEnv in the
576 monad; it augments it and returns the new TcGblEnv.
579 ------------------------------------------------
580 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
582 = do { -- Bring top level binders into scope
583 tcg_env <- importsFromLocalDecls group ;
584 setGblEnv tcg_env $ do {
586 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
588 -- Rename the source decls
589 (tcg_env, rn_decls) <- rnSrcDecls group ;
592 -- save the renamed syntax, if we want it
594 | Just grp <- tcg_rn_decls tcg_env
595 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
599 -- Dump trace of renaming part
600 rnDump (ppr rn_decls) ;
602 return (tcg_env', rn_decls)
605 ------------------------------------------------
606 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
607 tcTopSrcDecls boot_details
608 (HsGroup { hs_tyclds = tycl_decls,
609 hs_instds = inst_decls,
610 hs_derivds = deriv_decls,
611 hs_fords = foreign_decls,
612 hs_defds = default_decls,
613 hs_ruleds = rule_decls,
614 hs_valds = val_binds })
615 = do { -- Type-check the type and class decls, and all imported decls
616 -- The latter come in via tycl_decls
617 traceTc (text "Tc2") ;
619 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
620 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
621 -- an error we'd better stop now, to avoid a cascade
623 -- Make these type and class decls available to stuff slurped from interface files
624 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
627 setGblEnv tcg_env $ do {
628 -- Source-language instances, including derivings,
629 -- and import the supporting declarations
630 traceTc (text "Tc3") ;
631 (tcg_env, inst_infos, deriv_binds)
632 <- tcInstDecls1 tycl_decls inst_decls deriv_decls;
633 setGblEnv tcg_env $ do {
635 -- Foreign import declarations next. No zonking necessary
636 -- here; we can tuck them straight into the global environment.
637 traceTc (text "Tc4") ;
638 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
639 tcExtendGlobalValEnv fi_ids $ do {
641 -- Default declarations
642 traceTc (text "Tc4a") ;
643 default_tys <- tcDefaults default_decls ;
644 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
646 -- Value declarations next
647 -- We also typecheck any extra binds that came out
648 -- of the "deriving" process (deriv_binds)
649 traceTc (text "Tc5") ;
650 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
651 setLclTypeEnv tcl_env $ do {
653 -- Second pass over class and instance declarations,
654 traceTc (text "Tc6") ;
655 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
656 showLIE (text "after instDecls2") ;
659 -- They need to be zonked, so we return them
660 traceTc (text "Tc7") ;
661 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
664 rules <- tcRules rule_decls ;
667 traceTc (text "Tc7a") ;
668 tcg_env <- getGblEnv ;
669 let { all_binds = tc_val_binds `unionBags`
670 inst_binds `unionBags`
673 -- Extend the GblEnv with the (as yet un-zonked)
674 -- bindings, rules, foreign decls
675 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
676 tcg_rules = tcg_rules tcg_env ++ rules,
677 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
678 return (tcg_env', tcl_env)
683 %************************************************************************
687 %************************************************************************
690 checkMain :: TcM TcGblEnv
691 -- If we are in module Main, check that 'main' is defined.
693 = do { ghc_mode <- getGhcMode ;
694 tcg_env <- getGblEnv ;
696 let { main_mod = mainModIs dflags ;
697 main_fn = case mainFunIs dflags of {
698 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
699 Nothing -> main_RDR_Unqual } } ;
701 check_main ghc_mode tcg_env main_mod main_fn
705 check_main ghc_mode tcg_env main_mod main_fn
707 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
711 = addErrCtxt mainCtxt $
712 do { mb_main <- lookupSrcOcc_maybe main_fn
713 -- Check that 'main' is in scope
714 -- It might be imported from another module!
716 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
720 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
721 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
722 -- :Main.main :: IO () = runMainIO main
724 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
727 -- The function that the RTS invokes is always :Main.main,
728 -- which we call root_main_id.
729 -- (Because GHC allows the user to have a module not called
730 -- Main as the main module, we can't rely on the main function
731 -- being called "Main.main". That's why root_main_id has a fixed
733 -- We also make root_main_id an implicit Id, by making main_name
734 -- its parent (hence (Just main_name)). That has the effect
735 -- of preventing its type and unfolding from getting out into
736 -- the interface file. Otherwise we can end up with two defns
737 -- for 'main' in the interface file!
739 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
740 (mkVarOccFS FSLIT("main"))
741 (getSrcLoc main_name)
742 ; root_main_id = Id.mkExportedLocalId root_main_name ty
743 ; main_bind = noLoc (VarBind root_main_id main_expr) }
745 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
747 tcg_dus = tcg_dus tcg_env
748 `plusDU` usesOnly (unitFV main_name)
749 -- Record the use of 'main', so that we don't
750 -- complain about it being defined but not used
754 mod = tcg_mod tcg_env
756 complain_no_main | ghc_mode == Interactive = return ()
757 | otherwise = failWithTc noMainMsg
758 -- In interactive mode, don't worry about the absence of 'main'
759 -- In other modes, fail altogether, so that we don't go on
760 -- and complain a second time when processing the export list.
762 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
763 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
764 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
767 %*********************************************************
771 %*********************************************************
775 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
776 setInteractiveContext hsc_env icxt thing_inside
778 -- Initialise the tcg_inst_env with instances
779 -- from all home modules. This mimics the more selective
780 -- call to hptInstances in tcRnModule
781 dfuns = hptInstances hsc_env (\mod -> True)
783 updGblEnv (\env -> env {
784 tcg_rdr_env = ic_rn_gbl_env icxt,
785 tcg_type_env = ic_type_env icxt,
786 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
788 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
790 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
797 -> InteractiveContext
799 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
800 -- The returned [Name] is the same as the input except for
801 -- ExprStmt, in which case the returned [Name] is [itName]
803 -- The returned TypecheckedHsExpr is of type IO [ () ],
804 -- a list of the bound values, coerced to ().
806 tcRnStmt hsc_env ictxt rdr_stmt
807 = initTcPrintErrors hsc_env iNTERACTIVE $
808 setInteractiveContext hsc_env ictxt $ do {
810 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
811 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
812 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
815 -- The real work is done here
816 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
817 zonked_expr <- zonkTopLExpr tc_expr ;
818 zonked_ids <- zonkTopBndrs bound_ids ;
820 -- None of the Ids should be of unboxed type, because we
821 -- cast them all to HValues in the end!
822 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
824 traceTc (text "tcs 1") ;
825 let { -- (a) Make all the bound ids "global" ids, now that
826 -- they're notionally top-level bindings. This is
827 -- important: otherwise when we come to compile an expression
828 -- using these ids later, the byte code generator will consider
829 -- the occurrences to be free rather than global.
831 -- (b) Tidy their types; this is important, because :info may
832 -- ask to look at them, and :info expects the things it looks
833 -- up to have tidy types
834 global_ids = map globaliseAndTidy zonked_ids ;
836 -- Update the interactive context
837 rn_env = ic_rn_local_env ictxt ;
838 type_env = ic_type_env ictxt ;
840 bound_names = map idName global_ids ;
841 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
843 {- ---------------------------------------------
844 At one stage I removed any shadowed bindings from the type_env;
845 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
846 However, with Template Haskell they aren't necessarily inaccessible. Consider this
848 Prelude> let f n = n * 2 :: Int
849 Prelude> fName <- runQ [| f |]
850 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
852 Prelude> let f n = n * 3 :: Int
853 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
854 In the last line we use 'fName', which resolves to the *first* 'f'
855 in scope. If we delete it from the type env, GHCi crashes because
856 it doesn't expect that.
858 Hence this code is commented out
860 shadowed = [ n | name <- bound_names,
861 let rdr_name = mkRdrUnqual (nameOccName name),
862 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
863 filtered_type_env = delListFromNameEnv type_env shadowed ;
864 -------------------------------------------------- -}
866 new_type_env = extendTypeEnvWithIds type_env global_ids ;
867 new_ic = ictxt { ic_rn_local_env = new_rn_env,
868 ic_type_env = new_type_env }
871 dumpOptTcRn Opt_D_dump_tc
872 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
873 text "Typechecked expr" <+> ppr zonked_expr]) ;
875 returnM (new_ic, bound_names, zonked_expr)
878 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
879 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
881 globaliseAndTidy :: Id -> Id
883 -- Give the Id a Global Name, and tidy its type
884 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
886 tidy_type = tidyTopType (idType id)
889 Here is the grand plan, implemented in tcUserStmt
891 What you type The IO [HValue] that hscStmt returns
892 ------------- ------------------------------------
893 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
896 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
899 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
900 [NB: result not printed] bindings: [it]
902 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
903 result showable) bindings: [it]
905 expr (of non-IO type,
906 result not showable) ==> error
910 ---------------------------
911 type PlanResult = ([Id], LHsExpr Id)
912 type Plan = TcM PlanResult
914 runPlans :: [Plan] -> TcM PlanResult
915 -- Try the plans in order. If one fails (by raising an exn), try the next.
916 -- If one succeeds, take it.
917 runPlans [] = panic "runPlans"
919 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
922 mkPlan :: LStmt Name -> TcM PlanResult
923 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
924 = do { uniq <- newUnique -- is treated very specially
925 ; let fresh_it = itName uniq
926 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
927 matches = [mkMatch [] expr emptyLocalBinds]
928 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
929 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
930 (HsVar bindIOName) noSyntaxExpr
931 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
932 (HsVar thenIOName) placeHolderType
935 -- [it <- e; print it] but not if it::()
937 -- [let it = e; print it]
938 ; runPlans [ -- Plan A
939 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
940 ; it_ty <- zonkTcType (idType it_id)
941 ; ifM (isUnitTy it_ty) failM
944 -- Plan B; a naked bind statment
945 tcGhciStmts [bind_stmt],
947 -- Plan C; check that the let-binding is typeable all by itself.
948 -- If not, fail; if so, try to print it.
949 -- The two-step process avoids getting two errors: one from
950 -- the expression itself, and one from the 'print it' part
951 -- This two-step story is very clunky, alas
952 do { checkNoErrs (tcGhciStmts [let_stmt])
953 --- checkNoErrs defeats the error recovery of let-bindings
954 ; tcGhciStmts [let_stmt, print_it] }
957 mkPlan stmt@(L loc (BindStmt {}))
958 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
959 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
960 (HsVar thenIOName) placeHolderType
962 ; print_bind_result <- doptM Opt_PrintBindResult
963 ; let print_plan = do
964 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
965 ; v_ty <- zonkTcType (idType v_id)
966 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
970 -- [stmt; print v] but not if v::()
972 ; runPlans ((if print_bind_result then [print_plan] else []) ++
973 [tcGhciStmts [stmt]])
979 ---------------------------
980 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
982 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
983 ret_id <- tcLookupId returnIOName ; -- return @ IO
985 io_ty = mkTyConApp ioTyCon [] ;
986 ret_ty = mkListTy unitTy ;
987 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
988 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
989 (emptyRefinement, io_ret_ty) ;
991 names = map unLoc (collectLStmtsBinders stmts) ;
993 -- mk_return builds the expression
994 -- returnIO @ [()] [coerce () x, .., coerce () z]
996 -- Despite the inconvenience of building the type applications etc,
997 -- this *has* to be done in type-annotated post-typecheck form
998 -- because we are going to return a list of *polymorphic* values
999 -- coerced to type (). If we built a *source* stmt
1000 -- return [coerce x, ..., coerce z]
1001 -- then the type checker would instantiate x..z, and we wouldn't
1002 -- get their *polymorphic* values. (And we'd get ambiguity errs
1003 -- if they were overloaded, since they aren't applied to anything.)
1004 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
1005 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1006 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1010 -- OK, we're ready to typecheck the stmts
1011 traceTc (text "tcs 2") ;
1012 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1013 mappM tcLookupId names ;
1014 -- Look up the names right in the middle,
1015 -- where they will all be in scope
1017 -- Simplify the context
1018 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1019 -- checkNoErrs ensures that the plan fails if context redn fails
1021 return (ids, mkHsDictLet const_binds $
1022 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1027 tcRnExpr just finds the type of an expression
1031 -> InteractiveContext
1034 tcRnExpr hsc_env ictxt rdr_expr
1035 = initTcPrintErrors hsc_env iNTERACTIVE $
1036 setInteractiveContext hsc_env ictxt $ do {
1038 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1041 -- Now typecheck the expression;
1042 -- it might have a rank-2 type (e.g. :t runST)
1043 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1044 ((qtvs, dict_insts, _), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1045 tcSimplifyInteractive lie_top ;
1047 let { all_expr_ty = mkForAllTys qtvs $
1048 mkFunTys (map (idType . instToId) dict_insts) $
1050 zonkTcType all_expr_ty
1053 smpl_doc = ptext SLIT("main expression")
1056 tcRnType just finds the kind of a type
1060 -> InteractiveContext
1063 tcRnType hsc_env ictxt rdr_type
1064 = initTcPrintErrors hsc_env iNTERACTIVE $
1065 setInteractiveContext hsc_env ictxt $ do {
1067 rn_type <- rnLHsType doc rdr_type ;
1070 -- Now kind-check the type
1071 (ty', kind) <- kcHsType rn_type ;
1075 doc = ptext SLIT("In GHCi input")
1081 %************************************************************************
1083 More GHCi stuff, to do with browsing and getting info
1085 %************************************************************************
1089 -- ASSUMES that the module is either in the HomePackageTable or is
1090 -- a package module with an interface on disk. If neither of these is
1091 -- true, then the result will be an error indicating the interface
1092 -- could not be found.
1093 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1094 getModuleExports hsc_env mod
1097 checkMods = ic_toplev_scope ic ++ ic_exports ic
1099 initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod checkMods)
1101 -- Get the export avail info and also load all orphan and family-instance
1102 -- modules. Finally, check that the family instances of all modules in the
1103 -- interactive context are consistent (these modules are in the second
1105 tcGetModuleExports :: Module -> [Module] -> TcM [AvailInfo]
1106 tcGetModuleExports mod directlyImpMods
1107 = do { let doc = ptext SLIT("context for compiling statements")
1108 ; iface <- initIfaceTcRn $ loadSysInterface doc mod
1110 -- Load any orphan-module and family instance-module
1111 -- interfaces, so their instances are visible.
1112 ; loadOrphanModules (dep_orphs (mi_deps iface)) False
1113 ; loadOrphanModules (dep_finsts (mi_deps iface)) True
1115 -- Check that the family instances of all directly loaded
1116 -- modules are consistent.
1117 ; checkFamInstConsistency (dep_finsts (mi_deps iface)) directlyImpMods
1119 ; ifaceExportNames (mi_exports iface)
1122 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1123 tcRnLookupRdrName hsc_env rdr_name
1124 = initTcPrintErrors hsc_env iNTERACTIVE $
1125 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1126 lookup_rdr_name rdr_name
1128 lookup_rdr_name rdr_name = do {
1129 -- If the identifier is a constructor (begins with an
1130 -- upper-case letter), then we need to consider both
1131 -- constructor and type class identifiers.
1132 let { rdr_names = dataTcOccs rdr_name } ;
1134 -- results :: [Either Messages Name]
1135 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1137 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1138 -- The successful lookups will be (Just name)
1139 let { (warns_s, good_names) = unzip [ (msgs, name)
1140 | (msgs, Just name) <- results] ;
1141 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1143 -- Fail if nothing good happened, else add warnings
1144 if null good_names then
1145 -- No lookup succeeded, so
1146 -- pick the first error message and report it
1147 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1148 -- while the other is "X is not in scope",
1149 -- we definitely want the former; but we might pick the latter
1150 do { addMessages (head errs_s) ; failM }
1151 else -- Add deprecation warnings
1152 mapM_ addMessages warns_s ;
1157 tcRnRecoverDataCon :: HscEnv -> a -> IO (Maybe DataCon)
1158 tcRnRecoverDataCon hsc_env a
1159 = initTcPrintErrors hsc_env iNTERACTIVE $
1160 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1161 do name <- recoverDataCon a
1162 tcLookupDataCon name
1164 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1165 tcRnLookupName hsc_env name
1166 = initTcPrintErrors hsc_env iNTERACTIVE $
1167 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1171 tcRnGetInfo :: HscEnv
1173 -> IO (Maybe (TyThing, Fixity, [Instance]))
1175 -- Used to implemnent :info in GHCi
1177 -- Look up a RdrName and return all the TyThings it might be
1178 -- A capitalised RdrName is given to us in the DataName namespace,
1179 -- but we want to treat it as *both* a data constructor
1180 -- *and* as a type or class constructor;
1181 -- hence the call to dataTcOccs, and we return up to two results
1182 tcRnGetInfo hsc_env name
1183 = initTcPrintErrors hsc_env iNTERACTIVE $
1184 let ictxt = hsc_IC hsc_env in
1185 setInteractiveContext hsc_env ictxt $ do
1187 -- Load the interface for all unqualified types and classes
1188 -- That way we will find all the instance declarations
1189 -- (Packages have not orphan modules, and we assume that
1190 -- in the home package all relevant modules are loaded.)
1191 loadUnqualIfaces ictxt
1193 thing <- tcLookupGlobal name
1194 fixity <- lookupFixityRn name
1195 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1196 return (thing, fixity, ispecs)
1198 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1199 -- Filter the instances by the ones whose tycons (or clases resp)
1200 -- are in scope unqualified. Otherwise we list a whole lot too many!
1201 lookupInsts print_unqual (AClass cls)
1202 = do { inst_envs <- tcGetInstEnvs
1204 | ispec <- classInstances inst_envs cls
1205 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1207 lookupInsts print_unqual (ATyCon tc)
1208 = do { eps <- getEps -- Load all instances for all classes that are
1209 -- in the type environment (which are all the ones
1210 -- we've seen in any interface file so far)
1211 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1213 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1214 , let dfun = instanceDFunId ispec
1216 , plausibleDFun print_unqual dfun ] }
1218 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1219 tc_name = tyConName tc
1221 lookupInsts print_unqual other = return []
1223 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1224 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1226 ok name | isBuiltInSyntax name = True
1227 | isExternalName name =
1228 isNothing $ fst print_unqual (nameModule name)
1232 loadUnqualIfaces :: InteractiveContext -> TcM ()
1233 -- Load the home module for everything that is in scope unqualified
1234 -- This is so that we can accurately report the instances for
1236 loadUnqualIfaces ictxt
1238 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1240 unqual_mods = [ nameModule name
1241 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1242 let name = gre_name gre,
1243 not (isInternalName name),
1244 isTcOcc (nameOccName name), -- Types and classes only
1245 unQualOK gre ] -- In scope unqualified
1246 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1250 %************************************************************************
1254 %************************************************************************
1257 rnDump :: SDoc -> TcRn ()
1258 -- Dump, with a banner, if -ddump-rn
1259 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1261 tcDump :: TcGblEnv -> TcRn ()
1263 = do { dflags <- getDOpts ;
1265 -- Dump short output if -ddump-types or -ddump-tc
1266 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1267 (dumpTcRn short_dump) ;
1269 -- Dump bindings if -ddump-tc
1270 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1273 short_dump = pprTcGblEnv env
1274 full_dump = pprLHsBinds (tcg_binds env)
1275 -- NB: foreign x-d's have undefined's in their types;
1276 -- hence can't show the tc_fords
1279 = do { dflags <- getDOpts ;
1280 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1281 (dumpTcRn (pprModGuts mod_guts)) ;
1283 -- Dump bindings if -ddump-tc
1284 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1286 full_dump = pprCoreBindings (mg_binds mod_guts)
1288 -- It's unpleasant having both pprModGuts and pprModDetails here
1289 pprTcGblEnv :: TcGblEnv -> SDoc
1290 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1292 tcg_fam_insts = fam_insts,
1294 tcg_imports = imports })
1295 = vcat [ ppr_types insts type_env
1296 , ppr_tycons fam_insts type_env
1298 , ppr_fam_insts fam_insts
1299 , vcat (map ppr rules)
1300 , ppr_gen_tycons (typeEnvTyCons type_env)
1301 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1302 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1304 pprModGuts :: ModGuts -> SDoc
1305 pprModGuts (ModGuts { mg_types = type_env,
1307 = vcat [ ppr_types [] type_env,
1310 ppr_types :: [Instance] -> TypeEnv -> SDoc
1311 ppr_types insts type_env
1312 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1314 dfun_ids = map instanceDFunId insts
1315 ids = [id | id <- typeEnvIds type_env, want_sig id]
1316 want_sig id | opt_PprStyle_Debug = True
1317 | otherwise = isLocalId id &&
1318 isExternalName (idName id) &&
1319 not (id `elem` dfun_ids)
1320 -- isLocalId ignores data constructors, records selectors etc.
1321 -- The isExternalName ignores local dictionary and method bindings
1322 -- that the type checker has invented. Top-level user-defined things
1323 -- have External names.
1325 ppr_tycons :: [FamInst] -> TypeEnv -> SDoc
1326 ppr_tycons fam_insts type_env
1327 = text "TYPE CONSTRUCTORS" $$ nest 4 (ppr_tydecls tycons)
1329 fi_tycons = map famInstTyCon fam_insts
1330 tycons = [tycon | tycon <- typeEnvTyCons type_env, want_tycon tycon]
1331 want_tycon tycon | opt_PprStyle_Debug = True
1332 | otherwise = not (isImplicitTyCon tycon) &&
1333 isExternalName (tyConName tycon) &&
1334 not (tycon `elem` fi_tycons)
1336 ppr_insts :: [Instance] -> SDoc
1337 ppr_insts [] = empty
1338 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1340 ppr_fam_insts :: [FamInst] -> SDoc
1341 ppr_fam_insts [] = empty
1342 ppr_fam_insts fam_insts =
1343 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1345 ppr_sigs :: [Var] -> SDoc
1347 -- Print type signatures; sort by OccName
1348 = vcat (map ppr_sig (sortLe le_sig ids))
1350 le_sig id1 id2 = getOccName id1 <= getOccName id2
1351 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1353 ppr_tydecls :: [TyCon] -> SDoc
1355 -- Print type constructor info; sort by OccName
1356 = vcat (map ppr_tycon (sortLe le_sig tycons))
1358 le_sig tycon1 tycon2 = getOccName tycon1 <= getOccName tycon2
1360 | isCoercionTyCon tycon = ptext SLIT("coercion") <+> ppr tycon
1361 | otherwise = ppr (tyThingToIfaceDecl (ATyCon tycon))
1363 ppr_rules :: [CoreRule] -> SDoc
1364 ppr_rules [] = empty
1365 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1366 nest 4 (pprRules rs),
1369 ppr_gen_tycons [] = empty
1370 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1371 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]