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 )
87 import {- Kind parts of -} Type
96 import Control.Monad ( unless )
97 import Data.Maybe ( isJust )
102 %************************************************************************
104 Typecheck and rename a module
106 %************************************************************************
112 -> Bool -- True <=> save renamed syntax
113 -> Located (HsModule RdrName)
114 -> IO (Messages, Maybe TcGblEnv)
116 tcRnModule hsc_env hsc_src save_rn_syntax
117 (L loc (HsModule maybe_mod export_ies
118 import_decls local_decls mod_deprec _ module_info maybe_doc))
119 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
121 let { this_pkg = thisPackage (hsc_dflags hsc_env) ;
122 this_mod = case maybe_mod of
123 Nothing -> mAIN -- 'module M where' is omitted
124 Just (L _ mod) -> mkModule this_pkg mod } ;
127 initTc hsc_env hsc_src this_mod $
130 -- Deal with imports;
131 (rn_imports, rdr_env, imports) <- rnImports import_decls ;
133 let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)
134 ; dep_mods = imp_dep_mods imports
136 -- We want instance declarations from all home-package
137 -- modules below this one, including boot modules, except
138 -- ourselves. The 'except ourselves' is so that we don't
139 -- get the instances from this module's hs-boot file
140 ; want_instances :: ModuleName -> Bool
141 ; want_instances mod = mod `elemUFM` dep_mods
142 && mod /= moduleName this_mod
143 ; home_insts = hptInstances hsc_env want_instances
146 -- Record boot-file info in the EPS, so that it's
147 -- visible to loadHiBootInterface in tcRnSrcDecls,
148 -- and any other incrementally-performed imports
149 updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
151 -- Update the gbl env
153 gbl { tcg_rdr_env = plusOccEnv (tcg_rdr_env gbl) rdr_env,
154 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts,
155 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
156 tcg_rn_imports = if save_rn_syntax then
160 tcg_rn_decls = if save_rn_syntax then
166 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
167 -- Fail if there are any errors so far
168 -- The error printing (if needed) takes advantage
169 -- of the tcg_env we have now set
170 traceIf (text "rdr_env: " <+> ppr rdr_env) ;
173 -- Load any orphan-module and family instance-module
174 -- interfaces, so that their rules and instance decls will be
176 loadOrphanModules (imp_orphs imports) False ;
177 loadOrphanModules (imp_finsts imports) True ;
179 traceRn (text "rn1: checking family instance consistency") ;
180 let { directlyImpMods = map (\(mod, _, _) -> mod)
184 checkFamInstConsistency (imp_finsts imports) directlyImpMods ;
186 traceRn (text "rn1a") ;
187 -- Rename and type check the declarations
188 tcg_env <- if isHsBoot hsc_src then
189 tcRnHsBootDecls local_decls
191 tcRnSrcDecls local_decls ;
192 setGblEnv tcg_env $ do {
194 failIfErrsM ; -- reportDeprecations crashes sometimes
195 -- as a result of typechecker repairs (e.g. unboundNames)
196 traceRn (text "rn3") ;
198 -- Report the use of any deprecated things
199 -- We do this before processsing the export list so
200 -- that we don't bleat about re-exporting a deprecated
201 -- thing (especially via 'module Foo' export item)
202 -- Only uses in the body of the module are complained about
203 reportDeprecations (hsc_dflags hsc_env) tcg_env ;
205 -- Process the export list
206 (rn_exports, exports) <- rnExports (isJust maybe_mod) export_ies ;
208 traceRn (text "rn4") ;
210 -- Rename the Haddock documentation header
211 rn_module_doc <- rnMbHsDoc maybe_doc ;
213 -- Rename the Haddock module info
214 rn_description <- rnMbHsDoc (hmi_description module_info) ;
215 let { rn_module_info = module_info { hmi_description = rn_description } } ;
217 -- Check whether the entire module is deprecated
218 -- This happens only once per module
219 let { mod_deprecs = checkModDeprec mod_deprec } ;
221 -- Add exports and deprecations to envt
222 let { final_env = tcg_env { tcg_exports = exports,
223 tcg_rn_exports = if save_rn_syntax then
226 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly (availsToNameSet exports),
227 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
229 tcg_doc = rn_module_doc,
230 tcg_hmi = rn_module_info
232 -- A module deprecation over-rides the earlier ones
235 -- Report unused names
236 reportUnusedNames export_ies final_env ;
238 -- Dump output and return
245 %************************************************************************
247 Type-checking external-core modules
249 %************************************************************************
252 tcRnExtCore :: HscEnv
254 -> IO (Messages, Maybe ModGuts)
255 -- Nothing => some error occurred
257 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
258 -- The decls are IfaceDecls; all names are original names
259 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
261 initTc hsc_env ExtCoreFile this_mod $ do {
263 let { ldecls = map noLoc decls } ;
265 -- Deal with the type declarations; first bring their stuff
266 -- into scope, then rname them, then type check them
267 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
269 setGblEnv tcg_env $ do {
271 rn_decls <- rnTyClDecls ldecls ;
274 -- Dump trace of renaming part
275 rnDump (ppr rn_decls) ;
277 -- Typecheck them all together so that
278 -- any mutually recursive types are done right
279 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
280 -- Make the new type env available to stuff slurped from interface files
282 setGblEnv tcg_env $ do {
284 -- Now the core bindings
285 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
289 bndrs = bindersOfBinds core_binds ;
290 my_exports = map (Avail . idName) bndrs ;
291 -- ToDo: export the data types also?
293 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
295 mod_guts = ModGuts { mg_module = this_mod,
297 mg_usages = [], -- ToDo: compute usage
298 mg_dir_imps = [], -- ??
299 mg_deps = noDependencies, -- ??
300 mg_exports = my_exports,
301 mg_types = final_type_env,
302 mg_insts = tcg_insts tcg_env,
303 mg_fam_insts = tcg_fam_insts tcg_env,
305 mg_binds = core_binds,
308 mg_rdr_env = emptyGlobalRdrEnv,
309 mg_fix_env = emptyFixityEnv,
310 mg_deprecs = NoDeprecs,
311 mg_foreign = NoStubs,
312 mg_hpc_info = noHpcInfo
315 tcCoreDump mod_guts ;
320 mkFakeGroup decls -- Rather clumsy; lots of unused fields
321 = emptyRdrGroup { hs_tyclds = decls }
325 %************************************************************************
327 Type-checking the top level of a module
329 %************************************************************************
332 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
333 -- Returns the variables free in the decls
334 -- Reason: solely to report unused imports and bindings
336 = do { -- Load the hi-boot interface for this module, if any
337 -- We do this now so that the boot_names can be passed
338 -- to tcTyAndClassDecls, because the boot_names are
339 -- automatically considered to be loop breakers
341 boot_iface <- tcHiBootIface mod ;
343 -- Do all the declarations
344 (tc_envs, lie) <- getLIE $ tc_rn_src_decls boot_iface decls ;
346 -- Finish simplifying class constraints
348 -- tcSimplifyTop deals with constant or ambiguous InstIds.
349 -- How could there be ambiguous ones? They can only arise if a
350 -- top-level decl falls under the monomorphism restriction
351 -- and no subsequent decl instantiates its type.
353 -- We do this after checkMain, so that we use the type info
354 -- thaat checkMain adds
356 -- We do it with both global and local env in scope:
357 -- * the global env exposes the instances to tcSimplifyTop
358 -- * the local env exposes the local Ids to tcSimplifyTop,
359 -- so that we get better error messages (monomorphism restriction)
360 traceTc (text "Tc8") ;
361 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
363 -- Backsubstitution. This must be done last.
364 -- Even tcSimplifyTop may do some unification.
365 traceTc (text "Tc9") ;
366 let { (tcg_env, _) = tc_envs
367 ; TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
368 tcg_rules = rules, tcg_fords = fords } = tcg_env
369 ; all_binds = binds `unionBags` inst_binds } ;
371 (bind_ids, binds', fords', rules') <- zonkTopDecls all_binds rules fords ;
373 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
374 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
377 tcg_fords = fords' } } ;
379 -- Make the new type env available to stuff slurped from interface files
380 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
382 -- Compare the hi-boot iface (if any) with the real thing
383 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
385 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
388 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
389 -- Loops around dealing with each top level inter-splice group
390 -- in turn, until it's dealt with the entire module
391 tc_rn_src_decls boot_details ds
392 = do { let { (first_group, group_tail) = findSplice ds } ;
393 -- If ds is [] we get ([], Nothing)
395 -- Deal with decls up to, but not including, the first splice
396 (tcg_env, rn_decls) <- checkNoErrs $ rnTopSrcDecls first_group ;
397 -- checkNoErrs: don't typecheck if renaming failed
398 tc_envs <- setGblEnv tcg_env $
399 tcTopSrcDecls boot_details rn_decls ;
401 -- If there is no splice, we're nearly done
404 Nothing -> do { tcg_env <- checkMain ; -- Check for `main'
405 return (tcg_env, snd tc_envs)
408 -- If there's a splice, we must carry on
409 Just (SpliceDecl splice_expr, rest_ds) -> do {
411 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
414 -- Rename the splice expression, and get its supporting decls
415 (rn_splice_expr, splice_fvs) <- checkNoErrs (rnLExpr splice_expr) ;
416 -- checkNoErrs: don't typecheck if renaming failed
417 rnDump (ppr rn_splice_expr) ;
419 -- Execute the splice
420 spliced_decls <- tcSpliceDecls rn_splice_expr ;
422 -- Glue them on the front of the remaining decls and loop
423 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
424 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
429 %************************************************************************
431 Compiling hs-boot source files, and
432 comparing the hi-boot interface with the real thing
434 %************************************************************************
437 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
438 tcRnHsBootDecls decls
439 = do { let { (first_group, group_tail) = findSplice decls }
442 Just stuff -> spliceInHsBootErr stuff
445 -- Rename the declarations
446 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
447 ; setGblEnv tcg_env $ do {
449 -- Todo: check no foreign decls, no rules, no default decls
451 -- Typecheck type/class decls
452 ; traceTc (text "Tc2")
453 ; let tycl_decls = hs_tyclds rn_group
454 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
455 ; setGblEnv tcg_env $ do {
457 -- Typecheck instance decls
458 ; traceTc (text "Tc3")
459 ; (tcg_env, inst_infos, _binds)
460 <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group)
461 ; setGblEnv tcg_env $ do {
463 -- Typecheck value declarations
464 ; traceTc (text "Tc5")
465 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
468 -- No simplification or zonking to do
469 ; traceTc (text "Tc7a")
470 ; gbl_env <- getGblEnv
472 -- Make the final type-env
473 -- Include the dfun_ids so that their type sigs
474 -- are written into the interface file
475 ; let { type_env0 = tcg_type_env gbl_env
476 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
477 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
478 ; dfun_ids = map iDFunId inst_infos }
479 ; return (gbl_env { tcg_type_env = type_env2 })
482 spliceInHsBootErr (SpliceDecl (L loc _), _)
483 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
486 Once we've typechecked the body of the module, we want to compare what
487 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
490 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
491 -- Compare the hi-boot file for this module (if there is one)
492 -- with the type environment we've just come up with
493 -- In the common case where there is no hi-boot file, the list
494 -- of boot_names is empty.
496 -- The bindings we return give bindings for the dfuns defined in the
497 -- hs-boot file, such as $fbEqT = $fEqT
500 (TcGblEnv { tcg_insts = local_insts, tcg_fam_insts = local_fam_insts,
501 tcg_type_env = local_type_env })
502 (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts,
503 md_types = boot_type_env })
504 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts)) ;
505 ; mapM_ check_one (typeEnvElts boot_type_env)
506 ; dfun_binds <- mapM check_inst boot_insts
507 ; unless (null boot_fam_insts) $
508 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
509 "instances in boot files yet...")
510 -- FIXME: Why? The actual comparison is not hard, but what would
511 -- be the equivalent to the dfun bindings returned for class
512 -- instances? We can't easily equate tycons...
513 ; return (unionManyBags dfun_binds) }
516 | isImplicitTyThing boot_thing = return ()
517 | name `elem` dfun_names = return ()
518 | isWiredInName name = return () -- No checking for wired-in names. In particular,
519 -- 'error' is handled by a rather gross hack
520 -- (see comments in GHC.Err.hs-boot)
521 | Just real_thing <- lookupTypeEnv local_type_env name
522 = do { let boot_decl = tyThingToIfaceDecl boot_thing
523 real_decl = tyThingToIfaceDecl real_thing
524 ; checkTc (checkBootDecl boot_decl real_decl)
525 (bootMisMatch boot_thing boot_decl real_decl) }
526 -- The easiest way to check compatibility is to convert to
527 -- iface syntax, where we already have good comparison functions
529 = addErrTc (missingBootThing boot_thing)
531 name = getName boot_thing
533 dfun_names = map getName boot_insts
536 = case [dfun | inst <- local_insts,
537 let dfun = instanceDFunId inst,
538 idType dfun `tcEqType` boot_inst_ty ] of
539 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
540 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
542 boot_dfun = instanceDFunId boot_inst
543 boot_inst_ty = idType boot_dfun
544 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
547 missingBootThing thing
548 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
549 bootMisMatch thing boot_decl real_decl
550 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
551 ptext SLIT("Decl") <+> ppr real_decl,
552 ptext SLIT("Boot file:") <+> ppr boot_decl]
555 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
559 %************************************************************************
561 Type-checking the top level of a module
563 %************************************************************************
565 tcRnGroup takes a bunch of top-level source-code declarations, and
567 * gets supporting declarations from interface files
570 * and augments the TcGblEnv with the results
572 In Template Haskell it may be called repeatedly for each group of
573 declarations. It expects there to be an incoming TcGblEnv in the
574 monad; it augments it and returns the new TcGblEnv.
577 ------------------------------------------------
578 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
580 = do { -- Bring top level binders into scope
581 tcg_env <- importsFromLocalDecls group ;
582 setGblEnv tcg_env $ do {
584 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
586 -- Rename the source decls
587 (tcg_env, rn_decls) <- rnSrcDecls group ;
590 -- save the renamed syntax, if we want it
592 | Just grp <- tcg_rn_decls tcg_env
593 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
597 -- Dump trace of renaming part
598 rnDump (ppr rn_decls) ;
600 return (tcg_env', rn_decls)
603 ------------------------------------------------
604 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
605 tcTopSrcDecls boot_details
606 (HsGroup { hs_tyclds = tycl_decls,
607 hs_instds = inst_decls,
608 hs_derivds = deriv_decls,
609 hs_fords = foreign_decls,
610 hs_defds = default_decls,
611 hs_ruleds = rule_decls,
612 hs_valds = val_binds })
613 = do { -- Type-check the type and class decls, and all imported decls
614 -- The latter come in via tycl_decls
615 traceTc (text "Tc2") ;
617 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
618 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
619 -- an error we'd better stop now, to avoid a cascade
621 -- Make these type and class decls available to stuff slurped from interface files
622 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
625 setGblEnv tcg_env $ do {
626 -- Source-language instances, including derivings,
627 -- and import the supporting declarations
628 traceTc (text "Tc3") ;
629 (tcg_env, inst_infos, deriv_binds)
630 <- tcInstDecls1 tycl_decls inst_decls deriv_decls;
631 setGblEnv tcg_env $ do {
633 -- Foreign import declarations next. No zonking necessary
634 -- here; we can tuck them straight into the global environment.
635 traceTc (text "Tc4") ;
636 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
637 tcExtendGlobalValEnv fi_ids $ do {
639 -- Default declarations
640 traceTc (text "Tc4a") ;
641 default_tys <- tcDefaults default_decls ;
642 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
644 -- Value declarations next
645 -- We also typecheck any extra binds that came out
646 -- of the "deriving" process (deriv_binds)
647 traceTc (text "Tc5") ;
648 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
649 setLclTypeEnv tcl_env $ do {
651 -- Second pass over class and instance declarations,
652 traceTc (text "Tc6") ;
653 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
654 showLIE (text "after instDecls2") ;
657 -- They need to be zonked, so we return them
658 traceTc (text "Tc7") ;
659 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
662 rules <- tcRules rule_decls ;
665 traceTc (text "Tc7a") ;
666 tcg_env <- getGblEnv ;
667 let { all_binds = tc_val_binds `unionBags`
668 inst_binds `unionBags`
671 -- Extend the GblEnv with the (as yet un-zonked)
672 -- bindings, rules, foreign decls
673 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
674 tcg_rules = tcg_rules tcg_env ++ rules,
675 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
676 return (tcg_env', tcl_env)
681 %************************************************************************
685 %************************************************************************
688 checkMain :: TcM TcGblEnv
689 -- If we are in module Main, check that 'main' is defined.
691 = do { ghc_mode <- getGhcMode ;
692 tcg_env <- getGblEnv ;
694 let { main_mod = mainModIs dflags ;
695 main_fn = case mainFunIs dflags of {
696 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
697 Nothing -> main_RDR_Unqual } } ;
699 check_main ghc_mode tcg_env main_mod main_fn
703 check_main ghc_mode tcg_env main_mod main_fn
705 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
709 = addErrCtxt mainCtxt $
710 do { mb_main <- lookupSrcOcc_maybe main_fn
711 -- Check that 'main' is in scope
712 -- It might be imported from another module!
714 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
718 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
719 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
720 -- :Main.main :: IO () = runMainIO main
722 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
725 -- The function that the RTS invokes is always :Main.main,
726 -- which we call root_main_id.
727 -- (Because GHC allows the user to have a module not called
728 -- Main as the main module, we can't rely on the main function
729 -- being called "Main.main". That's why root_main_id has a fixed
731 -- We also make root_main_id an implicit Id, by making main_name
732 -- its parent (hence (Just main_name)). That has the effect
733 -- of preventing its type and unfolding from getting out into
734 -- the interface file. Otherwise we can end up with two defns
735 -- for 'main' in the interface file!
737 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
738 (mkVarOccFS FSLIT("main"))
739 (getSrcLoc main_name)
740 ; root_main_id = Id.mkExportedLocalId root_main_name ty
741 ; main_bind = noLoc (VarBind root_main_id main_expr) }
743 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
745 tcg_dus = tcg_dus tcg_env
746 `plusDU` usesOnly (unitFV main_name)
747 -- Record the use of 'main', so that we don't
748 -- complain about it being defined but not used
752 mod = tcg_mod tcg_env
754 complain_no_main | ghc_mode == Interactive = return ()
755 | otherwise = failWithTc noMainMsg
756 -- In interactive mode, don't worry about the absence of 'main'
757 -- In other modes, fail altogether, so that we don't go on
758 -- and complain a second time when processing the export list.
760 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
761 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
762 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
765 %*********************************************************
769 %*********************************************************
773 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
774 setInteractiveContext hsc_env icxt thing_inside
776 -- Initialise the tcg_inst_env with instances
777 -- from all home modules. This mimics the more selective
778 -- call to hptInstances in tcRnModule
779 dfuns = hptInstances hsc_env (\mod -> True)
781 updGblEnv (\env -> env {
782 tcg_rdr_env = ic_rn_gbl_env icxt,
783 tcg_type_env = ic_type_env icxt,
784 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
786 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
788 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
795 -> InteractiveContext
797 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
798 -- The returned [Name] is the same as the input except for
799 -- ExprStmt, in which case the returned [Name] is [itName]
801 -- The returned TypecheckedHsExpr is of type IO [ () ],
802 -- a list of the bound values, coerced to ().
804 tcRnStmt hsc_env ictxt rdr_stmt
805 = initTcPrintErrors hsc_env iNTERACTIVE $
806 setInteractiveContext hsc_env ictxt $ do {
808 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
809 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
810 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
813 -- The real work is done here
814 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
815 zonked_expr <- zonkTopLExpr tc_expr ;
816 zonked_ids <- zonkTopBndrs bound_ids ;
818 -- None of the Ids should be of unboxed type, because we
819 -- cast them all to HValues in the end!
820 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
822 traceTc (text "tcs 1") ;
823 let { -- (a) Make all the bound ids "global" ids, now that
824 -- they're notionally top-level bindings. This is
825 -- important: otherwise when we come to compile an expression
826 -- using these ids later, the byte code generator will consider
827 -- the occurrences to be free rather than global.
829 -- (b) Tidy their types; this is important, because :info may
830 -- ask to look at them, and :info expects the things it looks
831 -- up to have tidy types
832 global_ids = map globaliseAndTidy zonked_ids ;
834 -- Update the interactive context
835 rn_env = ic_rn_local_env ictxt ;
836 type_env = ic_type_env ictxt ;
838 bound_names = map idName global_ids ;
839 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
841 {- ---------------------------------------------
842 At one stage I removed any shadowed bindings from the type_env;
843 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
844 However, with Template Haskell they aren't necessarily inaccessible. Consider this
846 Prelude> let f n = n * 2 :: Int
847 Prelude> fName <- runQ [| f |]
848 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
850 Prelude> let f n = n * 3 :: Int
851 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
852 In the last line we use 'fName', which resolves to the *first* 'f'
853 in scope. If we delete it from the type env, GHCi crashes because
854 it doesn't expect that.
856 Hence this code is commented out
858 shadowed = [ n | name <- bound_names,
859 let rdr_name = mkRdrUnqual (nameOccName name),
860 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
861 filtered_type_env = delListFromNameEnv type_env shadowed ;
862 -------------------------------------------------- -}
864 new_type_env = extendTypeEnvWithIds type_env global_ids ;
865 new_ic = ictxt { ic_rn_local_env = new_rn_env,
866 ic_type_env = new_type_env }
869 dumpOptTcRn Opt_D_dump_tc
870 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
871 text "Typechecked expr" <+> ppr zonked_expr]) ;
873 returnM (new_ic, bound_names, zonked_expr)
876 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
877 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
879 globaliseAndTidy :: Id -> Id
881 -- Give the Id a Global Name, and tidy its type
882 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
884 tidy_type = tidyTopType (idType id)
887 Here is the grand plan, implemented in tcUserStmt
889 What you type The IO [HValue] that hscStmt returns
890 ------------- ------------------------------------
891 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
894 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
897 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
898 [NB: result not printed] bindings: [it]
900 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
901 result showable) bindings: [it]
903 expr (of non-IO type,
904 result not showable) ==> error
908 ---------------------------
909 type PlanResult = ([Id], LHsExpr Id)
910 type Plan = TcM PlanResult
912 runPlans :: [Plan] -> TcM PlanResult
913 -- Try the plans in order. If one fails (by raising an exn), try the next.
914 -- If one succeeds, take it.
915 runPlans [] = panic "runPlans"
917 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
920 mkPlan :: LStmt Name -> TcM PlanResult
921 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
922 = do { uniq <- newUnique -- is treated very specially
923 ; let fresh_it = itName uniq
924 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
925 matches = [mkMatch [] expr emptyLocalBinds]
926 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
927 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
928 (HsVar bindIOName) noSyntaxExpr
929 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
930 (HsVar thenIOName) placeHolderType
933 -- [it <- e; print it] but not if it::()
935 -- [let it = e; print it]
936 ; runPlans [ -- Plan A
937 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
938 ; it_ty <- zonkTcType (idType it_id)
939 ; ifM (isUnitTy it_ty) failM
942 -- Plan B; a naked bind statment
943 tcGhciStmts [bind_stmt],
945 -- Plan C; check that the let-binding is typeable all by itself.
946 -- If not, fail; if so, try to print it.
947 -- The two-step process avoids getting two errors: one from
948 -- the expression itself, and one from the 'print it' part
949 -- This two-step story is very clunky, alas
950 do { checkNoErrs (tcGhciStmts [let_stmt])
951 --- checkNoErrs defeats the error recovery of let-bindings
952 ; tcGhciStmts [let_stmt, print_it] }
955 mkPlan stmt@(L loc (BindStmt {}))
956 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
957 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
958 (HsVar thenIOName) placeHolderType
960 ; print_bind_result <- doptM Opt_PrintBindResult
961 ; let print_plan = do
962 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
963 ; v_ty <- zonkTcType (idType v_id)
964 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
968 -- [stmt; print v] but not if v::()
970 ; runPlans ((if print_bind_result then [print_plan] else []) ++
971 [tcGhciStmts [stmt]])
977 ---------------------------
978 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
980 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
981 ret_id <- tcLookupId returnIOName ; -- return @ IO
983 io_ty = mkTyConApp ioTyCon [] ;
984 ret_ty = mkListTy unitTy ;
985 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
986 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
987 (emptyRefinement, io_ret_ty) ;
989 names = map unLoc (collectLStmtsBinders stmts) ;
991 -- mk_return builds the expression
992 -- returnIO @ [()] [coerce () x, .., coerce () z]
994 -- Despite the inconvenience of building the type applications etc,
995 -- this *has* to be done in type-annotated post-typecheck form
996 -- because we are going to return a list of *polymorphic* values
997 -- coerced to type (). If we built a *source* stmt
998 -- return [coerce x, ..., coerce z]
999 -- then the type checker would instantiate x..z, and we wouldn't
1000 -- get their *polymorphic* values. (And we'd get ambiguity errs
1001 -- if they were overloaded, since they aren't applied to anything.)
1002 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
1003 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1004 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1008 -- OK, we're ready to typecheck the stmts
1009 traceTc (text "tcs 2") ;
1010 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1011 mappM tcLookupId names ;
1012 -- Look up the names right in the middle,
1013 -- where they will all be in scope
1015 -- Simplify the context
1016 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1017 -- checkNoErrs ensures that the plan fails if context redn fails
1019 return (ids, mkHsDictLet const_binds $
1020 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1025 tcRnExpr just finds the type of an expression
1029 -> InteractiveContext
1032 tcRnExpr hsc_env ictxt rdr_expr
1033 = initTcPrintErrors hsc_env iNTERACTIVE $
1034 setInteractiveContext hsc_env ictxt $ do {
1036 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1039 -- Now typecheck the expression;
1040 -- it might have a rank-2 type (e.g. :t runST)
1041 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1042 ((qtvs, dict_insts, _), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1043 tcSimplifyInteractive lie_top ;
1045 let { all_expr_ty = mkForAllTys qtvs $
1046 mkFunTys (map (idType . instToId) dict_insts) $
1048 zonkTcType all_expr_ty
1051 smpl_doc = ptext SLIT("main expression")
1054 tcRnType just finds the kind of a type
1058 -> InteractiveContext
1061 tcRnType hsc_env ictxt rdr_type
1062 = initTcPrintErrors hsc_env iNTERACTIVE $
1063 setInteractiveContext hsc_env ictxt $ do {
1065 rn_type <- rnLHsType doc rdr_type ;
1068 -- Now kind-check the type
1069 (ty', kind) <- kcHsType rn_type ;
1073 doc = ptext SLIT("In GHCi input")
1079 %************************************************************************
1081 More GHCi stuff, to do with browsing and getting info
1083 %************************************************************************
1087 -- ASSUMES that the module is either in the HomePackageTable or is
1088 -- a package module with an interface on disk. If neither of these is
1089 -- true, then the result will be an error indicating the interface
1090 -- could not be found.
1091 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1092 getModuleExports hsc_env mod
1093 = initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod)
1095 tcGetModuleExports :: Module -> TcM [AvailInfo]
1096 tcGetModuleExports mod = do
1097 let doc = ptext SLIT("context for compiling statements")
1098 iface <- initIfaceTcRn $ loadSysInterface doc mod
1099 loadOrphanModules (dep_orphs (mi_deps iface)) False
1100 -- Load any orphan-module interfaces,
1101 -- so their instances are visible
1102 loadOrphanModules (dep_finsts (mi_deps iface)) True
1103 -- Load any family instance-module interfaces,
1104 -- so all family instances are visible
1105 ifaceExportNames (mi_exports iface)
1107 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1108 tcRnLookupRdrName hsc_env rdr_name
1109 = initTcPrintErrors hsc_env iNTERACTIVE $
1110 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1111 lookup_rdr_name rdr_name
1113 lookup_rdr_name rdr_name = do {
1114 -- If the identifier is a constructor (begins with an
1115 -- upper-case letter), then we need to consider both
1116 -- constructor and type class identifiers.
1117 let { rdr_names = dataTcOccs rdr_name } ;
1119 -- results :: [Either Messages Name]
1120 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1122 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1123 -- The successful lookups will be (Just name)
1124 let { (warns_s, good_names) = unzip [ (msgs, name)
1125 | (msgs, Just name) <- results] ;
1126 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1128 -- Fail if nothing good happened, else add warnings
1129 if null good_names then
1130 -- No lookup succeeded, so
1131 -- pick the first error message and report it
1132 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1133 -- while the other is "X is not in scope",
1134 -- we definitely want the former; but we might pick the latter
1135 do { addMessages (head errs_s) ; failM }
1136 else -- Add deprecation warnings
1137 mapM_ addMessages warns_s ;
1142 tcRnRecoverDataCon :: HscEnv -> a -> IO (Maybe DataCon)
1143 tcRnRecoverDataCon hsc_env a
1144 = initTcPrintErrors hsc_env iNTERACTIVE $
1145 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1146 do name <- recoverDataCon a
1147 tcLookupDataCon name
1149 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1150 tcRnLookupName hsc_env name
1151 = initTcPrintErrors hsc_env iNTERACTIVE $
1152 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1156 tcRnGetInfo :: HscEnv
1158 -> IO (Maybe (TyThing, Fixity, [Instance]))
1160 -- Used to implemnent :info in GHCi
1162 -- Look up a RdrName and return all the TyThings it might be
1163 -- A capitalised RdrName is given to us in the DataName namespace,
1164 -- but we want to treat it as *both* a data constructor
1165 -- *and* as a type or class constructor;
1166 -- hence the call to dataTcOccs, and we return up to two results
1167 tcRnGetInfo hsc_env name
1168 = initTcPrintErrors hsc_env iNTERACTIVE $
1169 let ictxt = hsc_IC hsc_env in
1170 setInteractiveContext hsc_env ictxt $ do
1172 -- Load the interface for all unqualified types and classes
1173 -- That way we will find all the instance declarations
1174 -- (Packages have not orphan modules, and we assume that
1175 -- in the home package all relevant modules are loaded.)
1176 loadUnqualIfaces ictxt
1178 thing <- tcLookupGlobal name
1179 fixity <- lookupFixityRn name
1180 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1181 return (thing, fixity, ispecs)
1183 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1184 -- Filter the instances by the ones whose tycons (or clases resp)
1185 -- are in scope unqualified. Otherwise we list a whole lot too many!
1186 lookupInsts print_unqual (AClass cls)
1187 = do { inst_envs <- tcGetInstEnvs
1189 | ispec <- classInstances inst_envs cls
1190 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1192 lookupInsts print_unqual (ATyCon tc)
1193 = do { eps <- getEps -- Load all instances for all classes that are
1194 -- in the type environment (which are all the ones
1195 -- we've seen in any interface file so far)
1196 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1198 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1199 , let dfun = instanceDFunId ispec
1201 , plausibleDFun print_unqual dfun ] }
1203 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1204 tc_name = tyConName tc
1206 lookupInsts print_unqual other = return []
1208 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1209 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1211 ok name | isBuiltInSyntax name = True
1212 | isExternalName name =
1213 isNothing $ fst print_unqual (nameModule name)
1217 loadUnqualIfaces :: InteractiveContext -> TcM ()
1218 -- Load the home module for everything that is in scope unqualified
1219 -- This is so that we can accurately report the instances for
1221 loadUnqualIfaces ictxt
1223 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1225 unqual_mods = [ nameModule name
1226 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1227 let name = gre_name gre,
1228 not (isInternalName name),
1229 isTcOcc (nameOccName name), -- Types and classes only
1230 unQualOK gre ] -- In scope unqualified
1231 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1235 %************************************************************************
1239 %************************************************************************
1242 rnDump :: SDoc -> TcRn ()
1243 -- Dump, with a banner, if -ddump-rn
1244 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1246 tcDump :: TcGblEnv -> TcRn ()
1248 = do { dflags <- getDOpts ;
1250 -- Dump short output if -ddump-types or -ddump-tc
1251 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1252 (dumpTcRn short_dump) ;
1254 -- Dump bindings if -ddump-tc
1255 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1258 short_dump = pprTcGblEnv env
1259 full_dump = pprLHsBinds (tcg_binds env)
1260 -- NB: foreign x-d's have undefined's in their types;
1261 -- hence can't show the tc_fords
1264 = do { dflags <- getDOpts ;
1265 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1266 (dumpTcRn (pprModGuts mod_guts)) ;
1268 -- Dump bindings if -ddump-tc
1269 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1271 full_dump = pprCoreBindings (mg_binds mod_guts)
1273 -- It's unpleasant having both pprModGuts and pprModDetails here
1274 pprTcGblEnv :: TcGblEnv -> SDoc
1275 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1277 tcg_fam_insts = fam_insts,
1279 tcg_imports = imports })
1280 = vcat [ ppr_types insts type_env
1281 , ppr_tycons fam_insts type_env
1283 , ppr_fam_insts fam_insts
1284 , vcat (map ppr rules)
1285 , ppr_gen_tycons (typeEnvTyCons type_env)
1286 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1287 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1289 pprModGuts :: ModGuts -> SDoc
1290 pprModGuts (ModGuts { mg_types = type_env,
1292 = vcat [ ppr_types [] type_env,
1295 ppr_types :: [Instance] -> TypeEnv -> SDoc
1296 ppr_types insts type_env
1297 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1299 dfun_ids = map instanceDFunId insts
1300 ids = [id | id <- typeEnvIds type_env, want_sig id]
1301 want_sig id | opt_PprStyle_Debug = True
1302 | otherwise = isLocalId id &&
1303 isExternalName (idName id) &&
1304 not (id `elem` dfun_ids)
1305 -- isLocalId ignores data constructors, records selectors etc.
1306 -- The isExternalName ignores local dictionary and method bindings
1307 -- that the type checker has invented. Top-level user-defined things
1308 -- have External names.
1310 ppr_tycons :: [FamInst] -> TypeEnv -> SDoc
1311 ppr_tycons fam_insts type_env
1312 = text "TYPE CONSTRUCTORS" $$ nest 4 (ppr_tydecls tycons)
1314 fi_tycons = map famInstTyCon fam_insts
1315 tycons = [tycon | tycon <- typeEnvTyCons type_env, want_tycon tycon]
1316 want_tycon tycon | opt_PprStyle_Debug = True
1317 | otherwise = not (isImplicitTyCon tycon) &&
1318 isExternalName (tyConName tycon) &&
1319 not (tycon `elem` fi_tycons)
1321 ppr_insts :: [Instance] -> SDoc
1322 ppr_insts [] = empty
1323 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1325 ppr_fam_insts :: [FamInst] -> SDoc
1326 ppr_fam_insts [] = empty
1327 ppr_fam_insts fam_insts =
1328 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1330 ppr_sigs :: [Var] -> SDoc
1332 -- Print type signatures; sort by OccName
1333 = vcat (map ppr_sig (sortLe le_sig ids))
1335 le_sig id1 id2 = getOccName id1 <= getOccName id2
1336 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1338 ppr_tydecls :: [TyCon] -> SDoc
1340 -- Print type constructor info; sort by OccName
1341 = vcat (map ppr_tycon (sortLe le_sig tycons))
1343 le_sig tycon1 tycon2 = getOccName tycon1 <= getOccName tycon2
1345 | isCoercionTyCon tycon = ptext SLIT("coercion") <+> ppr tycon
1346 | otherwise = ppr (tyThingToIfaceDecl (ATyCon tycon))
1348 ppr_rules :: [CoreRule] -> SDoc
1349 ppr_rules [] = empty
1350 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1351 nest 4 (pprRules rs),
1354 ppr_gen_tycons [] = empty
1355 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1356 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]