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,
21 #include "HsVersions.h"
25 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
85 import {- Kind parts of -} Type
94 import Control.Monad ( unless )
95 import Data.Maybe ( isJust )
100 %************************************************************************
102 Typecheck and rename a module
104 %************************************************************************
110 -> Bool -- True <=> save renamed syntax
111 -> Located (HsModule RdrName)
112 -> IO (Messages, Maybe TcGblEnv)
114 tcRnModule hsc_env hsc_src save_rn_syntax
115 (L loc (HsModule maybe_mod export_ies
116 import_decls local_decls mod_deprec _ module_info maybe_doc))
117 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
119 let { this_pkg = thisPackage (hsc_dflags hsc_env) ;
120 this_mod = case maybe_mod of
121 Nothing -> mAIN -- 'module M where' is omitted
122 Just (L _ mod) -> mkModule this_pkg mod } ;
125 initTc hsc_env hsc_src this_mod $
128 -- Deal with imports;
129 (rn_imports, rdr_env, imports) <- rnImports import_decls ;
131 let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)
132 ; dep_mods = imp_dep_mods imports
134 -- We want instance declarations from all home-package
135 -- modules below this one, including boot modules, except
136 -- ourselves. The 'except ourselves' is so that we don't
137 -- get the instances from this module's hs-boot file
138 ; want_instances :: ModuleName -> Bool
139 ; want_instances mod = mod `elemUFM` dep_mods
140 && mod /= moduleName this_mod
141 ; home_insts = hptInstances hsc_env want_instances
144 -- Record boot-file info in the EPS, so that it's
145 -- visible to loadHiBootInterface in tcRnSrcDecls,
146 -- and any other incrementally-performed imports
147 updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
149 -- Update the gbl env
151 gbl { tcg_rdr_env = plusOccEnv (tcg_rdr_env gbl) rdr_env,
152 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts,
153 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
154 tcg_rn_imports = if save_rn_syntax then
158 tcg_rn_decls = if save_rn_syntax then
164 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
165 -- Fail if there are any errors so far
166 -- The error printing (if needed) takes advantage
167 -- of the tcg_env we have now set
168 traceIf (text "rdr_env: " <+> ppr rdr_env) ;
171 -- Load any orphan-module and family instance-module
172 -- interfaces, so that their rules and instance decls will be
174 loadOrphanModules (imp_orphs imports) False ;
175 loadOrphanModules (imp_finsts imports) True ;
177 let { directlyImpMods = map (\(mod, _, _) -> mod)
181 checkFamInstConsistency (imp_finsts imports) directlyImpMods ;
183 traceRn (text "rn1a") ;
184 -- Rename and type check the declarations
185 tcg_env <- if isHsBoot hsc_src then
186 tcRnHsBootDecls local_decls
188 tcRnSrcDecls local_decls ;
189 setGblEnv tcg_env $ do {
191 traceRn (text "rn3") ;
193 -- Report the use of any deprecated things
194 -- We do this before processsing the export list so
195 -- that we don't bleat about re-exporting a deprecated
196 -- thing (especially via 'module Foo' export item)
197 -- Only uses in the body of the module are complained about
198 reportDeprecations (hsc_dflags hsc_env) tcg_env ;
200 -- Process the export list
201 (rn_exports, exports) <- rnExports (isJust maybe_mod) export_ies ;
203 traceRn (text "rn4") ;
205 -- Rename the Haddock documentation header
206 rn_module_doc <- rnMbHsDoc maybe_doc ;
208 -- Rename the Haddock module info
209 rn_description <- rnMbHsDoc (hmi_description module_info) ;
210 let { rn_module_info = module_info { hmi_description = rn_description } } ;
212 -- Check whether the entire module is deprecated
213 -- This happens only once per module
214 let { mod_deprecs = checkModDeprec mod_deprec } ;
216 -- Add exports and deprecations to envt
217 let { final_env = tcg_env { tcg_exports = exports,
218 tcg_rn_exports = if save_rn_syntax then
221 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly (availsToNameSet exports),
222 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
224 tcg_doc = rn_module_doc,
225 tcg_hmi = rn_module_info
227 -- A module deprecation over-rides the earlier ones
230 -- Report unused names
231 reportUnusedNames export_ies final_env ;
233 -- Dump output and return
240 %************************************************************************
242 Type-checking external-core modules
244 %************************************************************************
247 tcRnExtCore :: HscEnv
249 -> IO (Messages, Maybe ModGuts)
250 -- Nothing => some error occurred
252 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
253 -- The decls are IfaceDecls; all names are original names
254 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
256 initTc hsc_env ExtCoreFile this_mod $ do {
258 let { ldecls = map noLoc decls } ;
260 -- Deal with the type declarations; first bring their stuff
261 -- into scope, then rname them, then type check them
262 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
264 setGblEnv tcg_env $ do {
266 rn_decls <- rnTyClDecls ldecls ;
269 -- Dump trace of renaming part
270 rnDump (ppr rn_decls) ;
272 -- Typecheck them all together so that
273 -- any mutually recursive types are done right
274 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
275 -- Make the new type env available to stuff slurped from interface files
277 setGblEnv tcg_env $ do {
279 -- Now the core bindings
280 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
284 bndrs = bindersOfBinds core_binds ;
285 my_exports = map (Avail . idName) bndrs ;
286 -- ToDo: export the data types also?
288 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
290 mod_guts = ModGuts { mg_module = this_mod,
292 mg_usages = [], -- ToDo: compute usage
293 mg_dir_imps = [], -- ??
294 mg_deps = noDependencies, -- ??
295 mg_exports = my_exports,
296 mg_types = final_type_env,
297 mg_insts = tcg_insts tcg_env,
298 mg_fam_insts = tcg_fam_insts tcg_env,
300 mg_binds = core_binds,
303 mg_rdr_env = emptyGlobalRdrEnv,
304 mg_fix_env = emptyFixityEnv,
305 mg_deprecs = NoDeprecs,
309 tcCoreDump mod_guts ;
314 mkFakeGroup decls -- Rather clumsy; lots of unused fields
315 = emptyRdrGroup { hs_tyclds = decls }
319 %************************************************************************
321 Type-checking the top level of a module
323 %************************************************************************
326 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
327 -- Returns the variables free in the decls
328 -- Reason: solely to report unused imports and bindings
330 = do { -- Load the hi-boot interface for this module, if any
331 -- We do this now so that the boot_names can be passed
332 -- to tcTyAndClassDecls, because the boot_names are
333 -- automatically considered to be loop breakers
335 boot_iface <- tcHiBootIface mod ;
337 -- Do all the declarations
338 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_iface decls) ;
340 -- tcSimplifyTop deals with constant or ambiguous InstIds.
341 -- How could there be ambiguous ones? They can only arise if a
342 -- top-level decl falls under the monomorphism
343 -- restriction, and no subsequent decl instantiates its
344 -- type. (Usually, ambiguous type variables are resolved
345 -- during the generalisation step.)
346 traceTc (text "Tc8") ;
347 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
348 -- Setting the global env exposes the instances to tcSimplifyTop
349 -- Setting the local env exposes the local Ids to tcSimplifyTop,
350 -- so that we get better error messages (monomorphism restriction)
352 -- Backsubstitution. This must be done last.
353 -- Even tcSimplifyTop may do some unification.
354 traceTc (text "Tc9") ;
355 let { (tcg_env, _) = tc_envs ;
356 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
357 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
359 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
362 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
363 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
366 tcg_fords = fords' } } ;
368 -- Make the new type env available to stuff slurped from interface files
369 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
371 -- Compare the hi-boot iface (if any) with the real thing
372 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
374 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
377 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
378 -- Loops around dealing with each top level inter-splice group
379 -- in turn, until it's dealt with the entire module
380 tc_rn_src_decls boot_details ds
381 = do { let { (first_group, group_tail) = findSplice ds } ;
382 -- If ds is [] we get ([], Nothing)
384 -- Type check the decls up to, but not including, the first splice
385 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_details first_group ;
387 -- Bale out if errors; for example, error recovery when checking
388 -- the RHS of 'main' can mean that 'main' is not in the envt for
389 -- the subsequent checkMain test
394 -- If there is no splice, we're nearly done
396 Nothing -> do { -- Last thing: check for `main'
397 tcg_env <- checkMain ;
398 return (tcg_env, tcl_env)
401 -- If there's a splice, we must carry on
402 Just (SpliceDecl splice_expr, rest_ds) -> do {
404 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
407 -- Rename the splice expression, and get its supporting decls
408 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
409 failIfErrsM ; -- Don't typecheck if renaming failed
410 rnDump (ppr rn_splice_expr) ;
412 -- Execute the splice
413 spliced_decls <- tcSpliceDecls rn_splice_expr ;
415 -- Glue them on the front of the remaining decls and loop
416 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
417 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
422 %************************************************************************
424 Compiling hs-boot source files, and
425 comparing the hi-boot interface with the real thing
427 %************************************************************************
430 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
431 tcRnHsBootDecls decls
432 = do { let { (first_group, group_tail) = findSplice decls }
435 Just stuff -> spliceInHsBootErr stuff
438 -- Rename the declarations
439 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
440 ; setGblEnv tcg_env $ do {
442 -- Todo: check no foreign decls, no rules, no default decls
444 -- Typecheck type/class decls
445 ; traceTc (text "Tc2")
446 ; let tycl_decls = hs_tyclds rn_group
447 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
448 ; setGblEnv tcg_env $ do {
450 -- Typecheck instance decls
451 ; traceTc (text "Tc3")
452 ; (tcg_env, inst_infos, _binds)
453 <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group)
454 ; setGblEnv tcg_env $ do {
456 -- Typecheck value declarations
457 ; traceTc (text "Tc5")
458 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
461 -- No simplification or zonking to do
462 ; traceTc (text "Tc7a")
463 ; gbl_env <- getGblEnv
465 -- Make the final type-env
466 -- Include the dfun_ids so that their type sigs
467 -- are written into the interface file
468 ; let { type_env0 = tcg_type_env gbl_env
469 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
470 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
471 ; dfun_ids = map iDFunId inst_infos }
472 ; return (gbl_env { tcg_type_env = type_env2 })
475 spliceInHsBootErr (SpliceDecl (L loc _), _)
476 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
479 Once we've typechecked the body of the module, we want to compare what
480 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
483 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
484 -- Compare the hi-boot file for this module (if there is one)
485 -- with the type environment we've just come up with
486 -- In the common case where there is no hi-boot file, the list
487 -- of boot_names is empty.
489 -- The bindings we return give bindings for the dfuns defined in the
490 -- hs-boot file, such as $fbEqT = $fEqT
493 (TcGblEnv { tcg_insts = local_insts, tcg_fam_insts = local_fam_insts,
494 tcg_type_env = local_type_env })
495 (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts,
496 md_types = boot_type_env })
497 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts)) ;
498 ; mapM_ check_one (typeEnvElts boot_type_env)
499 ; dfun_binds <- mapM check_inst boot_insts
500 ; unless (null boot_fam_insts) $
501 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
502 "instances in boot files yet...")
503 -- FIXME: Why? The actual comparison is not hard, but what would
504 -- be the equivalent to the dfun bindings returned for class
505 -- instances? We can't easily equate tycons...
506 ; return (unionManyBags dfun_binds) }
509 | isImplicitTyThing boot_thing = return ()
510 | name `elem` dfun_names = return ()
511 | isWiredInName name = return () -- No checking for wired-in names. In particular,
512 -- 'error' is handled by a rather gross hack
513 -- (see comments in GHC.Err.hs-boot)
514 | Just real_thing <- lookupTypeEnv local_type_env name
515 = do { let boot_decl = tyThingToIfaceDecl boot_thing
516 real_decl = tyThingToIfaceDecl real_thing
517 ; checkTc (checkBootDecl boot_decl real_decl)
518 (bootMisMatch boot_thing boot_decl real_decl) }
519 -- The easiest way to check compatibility is to convert to
520 -- iface syntax, where we already have good comparison functions
522 = addErrTc (missingBootThing boot_thing)
524 name = getName boot_thing
526 dfun_names = map getName boot_insts
529 = case [dfun | inst <- local_insts,
530 let dfun = instanceDFunId inst,
531 idType dfun `tcEqType` boot_inst_ty ] of
532 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
533 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
535 boot_dfun = instanceDFunId boot_inst
536 boot_inst_ty = idType boot_dfun
537 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
540 missingBootThing thing
541 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
542 bootMisMatch thing boot_decl real_decl
543 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
544 ptext SLIT("Decl") <+> ppr real_decl,
545 ptext SLIT("Boot file:") <+> ppr boot_decl]
548 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
552 %************************************************************************
554 Type-checking the top level of a module
556 %************************************************************************
558 tcRnGroup takes a bunch of top-level source-code declarations, and
560 * gets supporting declarations from interface files
563 * and augments the TcGblEnv with the results
565 In Template Haskell it may be called repeatedly for each group of
566 declarations. It expects there to be an incoming TcGblEnv in the
567 monad; it augments it and returns the new TcGblEnv.
570 tcRnGroup :: ModDetails -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
571 -- Returns the variables free in the decls, for unused-binding reporting
572 tcRnGroup boot_details decls
573 = do { -- Rename the declarations
574 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
575 setGblEnv tcg_env $ do {
577 -- Typecheck the declarations
578 tcTopSrcDecls boot_details rn_decls
581 ------------------------------------------------
582 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
584 = do { -- Bring top level binders into scope
585 tcg_env <- importsFromLocalDecls group ;
586 setGblEnv tcg_env $ do {
588 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
590 -- Rename the source decls
591 (tcg_env, rn_decls) <- rnSrcDecls group ;
594 -- save the renamed syntax, if we want it
596 | Just grp <- tcg_rn_decls tcg_env
597 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
601 -- Dump trace of renaming part
602 rnDump (ppr rn_decls) ;
604 return (tcg_env', rn_decls)
607 ------------------------------------------------
608 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
609 tcTopSrcDecls boot_details
610 (HsGroup { hs_tyclds = tycl_decls,
611 hs_instds = inst_decls,
612 hs_derivds = deriv_decls,
613 hs_fords = foreign_decls,
614 hs_defds = default_decls,
615 hs_ruleds = rule_decls,
616 hs_valds = val_binds })
617 = do { -- Type-check the type and class decls, and all imported decls
618 -- The latter come in via tycl_decls
619 traceTc (text "Tc2") ;
621 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
622 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
623 -- an error we'd better stop now, to avoid a cascade
625 -- Make these type and class decls available to stuff slurped from interface files
626 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
629 setGblEnv tcg_env $ do {
630 -- Source-language instances, including derivings,
631 -- and import the supporting declarations
632 traceTc (text "Tc3") ;
633 (tcg_env, inst_infos, deriv_binds)
634 <- tcInstDecls1 tycl_decls inst_decls deriv_decls;
635 setGblEnv tcg_env $ do {
637 -- Foreign import declarations next. No zonking necessary
638 -- here; we can tuck them straight into the global environment.
639 traceTc (text "Tc4") ;
640 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
641 tcExtendGlobalValEnv fi_ids $ do {
643 -- Default declarations
644 traceTc (text "Tc4a") ;
645 default_tys <- tcDefaults default_decls ;
646 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
648 -- Value declarations next
649 -- We also typecheck any extra binds that came out
650 -- of the "deriving" process (deriv_binds)
651 traceTc (text "Tc5") ;
652 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
653 setLclTypeEnv tcl_env $ do {
655 -- Second pass over class and instance declarations,
656 traceTc (text "Tc6") ;
657 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
658 showLIE (text "after instDecls2") ;
661 -- They need to be zonked, so we return them
662 traceTc (text "Tc7") ;
663 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
666 rules <- tcRules rule_decls ;
669 traceTc (text "Tc7a") ;
670 tcg_env <- getGblEnv ;
671 let { all_binds = tc_val_binds `unionBags`
672 inst_binds `unionBags`
675 -- Extend the GblEnv with the (as yet un-zonked)
676 -- bindings, rules, foreign decls
677 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
678 tcg_rules = tcg_rules tcg_env ++ rules,
679 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
680 return (tcg_env', tcl_env)
685 %************************************************************************
689 %************************************************************************
692 checkMain :: TcM TcGblEnv
693 -- If we are in module Main, check that 'main' is defined.
695 = do { ghc_mode <- getGhcMode ;
696 tcg_env <- getGblEnv ;
698 let { main_mod = mainModIs dflags ;
699 main_fn = case mainFunIs dflags of {
700 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
701 Nothing -> main_RDR_Unqual } } ;
703 check_main ghc_mode tcg_env main_mod main_fn
707 check_main ghc_mode tcg_env main_mod main_fn
709 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
713 = addErrCtxt mainCtxt $
714 do { mb_main <- lookupSrcOcc_maybe main_fn
715 -- Check that 'main' is in scope
716 -- It might be imported from another module!
718 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
722 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
723 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
724 -- :Main.main :: IO () = runMainIO main
726 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
729 -- The function that the RTS invokes is always :Main.main,
730 -- which we call root_main_id.
731 -- (Because GHC allows the user to have a module not called
732 -- Main as the main module, we can't rely on the main function
733 -- being called "Main.main". That's why root_main_id has a fixed
735 -- We also make root_main_id an implicit Id, by making main_name
736 -- its parent (hence (Just main_name)). That has the effect
737 -- of preventing its type and unfolding from getting out into
738 -- the interface file. Otherwise we can end up with two defns
739 -- for 'main' in the interface file!
741 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
742 (mkVarOccFS FSLIT("main"))
743 (getSrcLoc main_name)
744 ; root_main_id = Id.mkExportedLocalId root_main_name ty
745 ; main_bind = noLoc (VarBind root_main_id main_expr) }
747 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
749 tcg_dus = tcg_dus tcg_env
750 `plusDU` usesOnly (unitFV main_name)
751 -- Record the use of 'main', so that we don't
752 -- complain about it being defined but not used
756 mod = tcg_mod tcg_env
758 complain_no_main | ghc_mode == Interactive = return ()
759 | otherwise = failWithTc noMainMsg
760 -- In interactive mode, don't worry about the absence of 'main'
761 -- In other modes, fail altogether, so that we don't go on
762 -- and complain a second time when processing the export list.
764 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
765 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
766 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
769 %*********************************************************
773 %*********************************************************
777 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
778 setInteractiveContext hsc_env icxt thing_inside
780 -- Initialise the tcg_inst_env with instances
781 -- from all home modules. This mimics the more selective
782 -- call to hptInstances in tcRnModule
783 dfuns = hptInstances hsc_env (\mod -> True)
785 updGblEnv (\env -> env {
786 tcg_rdr_env = ic_rn_gbl_env icxt,
787 tcg_type_env = ic_type_env icxt,
788 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
790 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
792 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
799 -> InteractiveContext
801 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
802 -- The returned [Name] is the same as the input except for
803 -- ExprStmt, in which case the returned [Name] is [itName]
805 -- The returned TypecheckedHsExpr is of type IO [ () ],
806 -- a list of the bound values, coerced to ().
808 tcRnStmt hsc_env ictxt rdr_stmt
809 = initTcPrintErrors hsc_env iNTERACTIVE $
810 setInteractiveContext hsc_env ictxt $ do {
812 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
813 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
814 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
817 -- The real work is done here
818 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
819 zonked_expr <- zonkTopLExpr tc_expr ;
820 zonked_ids <- zonkTopBndrs bound_ids ;
822 -- None of the Ids should be of unboxed type, because we
823 -- cast them all to HValues in the end!
824 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
826 traceTc (text "tcs 1") ;
827 let { -- (a) Make all the bound ids "global" ids, now that
828 -- they're notionally top-level bindings. This is
829 -- important: otherwise when we come to compile an expression
830 -- using these ids later, the byte code generator will consider
831 -- the occurrences to be free rather than global.
833 -- (b) Tidy their types; this is important, because :info may
834 -- ask to look at them, and :info expects the things it looks
835 -- up to have tidy types
836 global_ids = map globaliseAndTidy zonked_ids ;
838 -- Update the interactive context
839 rn_env = ic_rn_local_env ictxt ;
840 type_env = ic_type_env ictxt ;
842 bound_names = map idName global_ids ;
843 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
845 {- ---------------------------------------------
846 At one stage I removed any shadowed bindings from the type_env;
847 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
848 However, with Template Haskell they aren't necessarily inaccessible. Consider this
850 Prelude> let f n = n * 2 :: Int
851 Prelude> fName <- runQ [| f |]
852 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
854 Prelude> let f n = n * 3 :: Int
855 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
856 In the last line we use 'fName', which resolves to the *first* 'f'
857 in scope. If we delete it from the type env, GHCi crashes because
858 it doesn't expect that.
860 Hence this code is commented out
862 shadowed = [ n | name <- bound_names,
863 let rdr_name = mkRdrUnqual (nameOccName name),
864 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
865 filtered_type_env = delListFromNameEnv type_env shadowed ;
866 -------------------------------------------------- -}
868 new_type_env = extendTypeEnvWithIds type_env global_ids ;
869 new_ic = ictxt { ic_rn_local_env = new_rn_env,
870 ic_type_env = new_type_env }
873 dumpOptTcRn Opt_D_dump_tc
874 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
875 text "Typechecked expr" <+> ppr zonked_expr]) ;
877 returnM (new_ic, bound_names, zonked_expr)
880 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
881 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
883 globaliseAndTidy :: Id -> Id
885 -- Give the Id a Global Name, and tidy its type
886 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
888 tidy_type = tidyTopType (idType id)
891 Here is the grand plan, implemented in tcUserStmt
893 What you type The IO [HValue] that hscStmt returns
894 ------------- ------------------------------------
895 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
898 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
901 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
902 [NB: result not printed] bindings: [it]
904 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
905 result showable) bindings: [it]
907 expr (of non-IO type,
908 result not showable) ==> error
912 ---------------------------
913 type PlanResult = ([Id], LHsExpr Id)
914 type Plan = TcM PlanResult
916 runPlans :: [Plan] -> TcM PlanResult
917 -- Try the plans in order. If one fails (by raising an exn), try the next.
918 -- If one succeeds, take it.
919 runPlans [] = panic "runPlans"
921 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
924 mkPlan :: LStmt Name -> TcM PlanResult
925 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
926 = do { uniq <- newUnique -- is treated very specially
927 ; let fresh_it = itName uniq
928 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
929 matches = [mkMatch [] expr emptyLocalBinds]
930 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
931 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
932 (HsVar bindIOName) noSyntaxExpr
933 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
934 (HsVar thenIOName) placeHolderType
937 -- [it <- e; print it] but not if it::()
939 -- [let it = e; print it]
940 ; runPlans [ -- Plan A
941 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
942 ; it_ty <- zonkTcType (idType it_id)
943 ; ifM (isUnitTy it_ty) failM
946 -- Plan B; a naked bind statment
947 tcGhciStmts [bind_stmt],
949 -- Plan C; check that the let-binding is typeable all by itself.
950 -- If not, fail; if so, try to print it.
951 -- The two-step process avoids getting two errors: one from
952 -- the expression itself, and one from the 'print it' part
953 -- This two-step story is very clunky, alas
954 do { checkNoErrs (tcGhciStmts [let_stmt])
955 --- checkNoErrs defeats the error recovery of let-bindings
956 ; tcGhciStmts [let_stmt, print_it] }
959 mkPlan stmt@(L loc (BindStmt {}))
960 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
961 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
962 (HsVar thenIOName) placeHolderType
964 ; print_bind_result <- doptM Opt_PrintBindResult
965 ; let print_plan = do
966 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
967 ; v_ty <- zonkTcType (idType v_id)
968 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
972 -- [stmt; print v] but not if v::()
974 ; runPlans ((if print_bind_result then [print_plan] else []) ++
975 [tcGhciStmts [stmt]])
981 ---------------------------
982 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
984 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
985 ret_id <- tcLookupId returnIOName ; -- return @ IO
987 io_ty = mkTyConApp ioTyCon [] ;
988 ret_ty = mkListTy unitTy ;
989 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
990 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
991 (emptyRefinement, io_ret_ty) ;
993 names = map unLoc (collectLStmtsBinders stmts) ;
995 -- mk_return builds the expression
996 -- returnIO @ [()] [coerce () x, .., coerce () z]
998 -- Despite the inconvenience of building the type applications etc,
999 -- this *has* to be done in type-annotated post-typecheck form
1000 -- because we are going to return a list of *polymorphic* values
1001 -- coerced to type (). If we built a *source* stmt
1002 -- return [coerce x, ..., coerce z]
1003 -- then the type checker would instantiate x..z, and we wouldn't
1004 -- get their *polymorphic* values. (And we'd get ambiguity errs
1005 -- if they were overloaded, since they aren't applied to anything.)
1006 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
1007 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1008 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1012 -- OK, we're ready to typecheck the stmts
1013 traceTc (text "tcs 2") ;
1014 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1015 mappM tcLookupId names ;
1016 -- Look up the names right in the middle,
1017 -- where they will all be in scope
1019 -- Simplify the context
1020 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1021 -- checkNoErrs ensures that the plan fails if context redn fails
1023 return (ids, mkHsDictLet const_binds $
1024 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1029 tcRnExpr just finds the type of an expression
1033 -> InteractiveContext
1036 tcRnExpr hsc_env ictxt rdr_expr
1037 = initTcPrintErrors hsc_env iNTERACTIVE $
1038 setInteractiveContext hsc_env ictxt $ do {
1040 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1043 -- Now typecheck the expression;
1044 -- it might have a rank-2 type (e.g. :t runST)
1045 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1046 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1047 tcSimplifyInteractive lie_top ;
1048 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
1050 let { all_expr_ty = mkForAllTys qtvs' $
1051 mkFunTys (map idType dict_ids) $
1053 zonkTcType all_expr_ty
1056 smpl_doc = ptext SLIT("main expression")
1059 tcRnType just finds the kind of a type
1063 -> InteractiveContext
1066 tcRnType hsc_env ictxt rdr_type
1067 = initTcPrintErrors hsc_env iNTERACTIVE $
1068 setInteractiveContext hsc_env ictxt $ do {
1070 rn_type <- rnLHsType doc rdr_type ;
1073 -- Now kind-check the type
1074 (ty', kind) <- kcHsType rn_type ;
1078 doc = ptext SLIT("In GHCi input")
1084 %************************************************************************
1086 More GHCi stuff, to do with browsing and getting info
1088 %************************************************************************
1092 -- ASSUMES that the module is either in the HomePackageTable or is
1093 -- a package module with an interface on disk. If neither of these is
1094 -- true, then the result will be an error indicating the interface
1095 -- could not be found.
1096 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1097 getModuleExports hsc_env mod
1098 = initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod)
1100 tcGetModuleExports :: Module -> TcM [AvailInfo]
1101 tcGetModuleExports mod = do
1102 let doc = ptext SLIT("context for compiling statements")
1103 iface <- initIfaceTcRn $ loadSysInterface doc mod
1104 loadOrphanModules (dep_orphs (mi_deps iface)) False
1105 -- Load any orphan-module interfaces,
1106 -- so their instances are visible
1107 loadOrphanModules (dep_finsts (mi_deps iface)) True
1108 -- Load any family instance-module interfaces,
1109 -- so all family instances are visible
1110 ifaceExportNames (mi_exports iface)
1112 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1113 tcRnLookupRdrName hsc_env rdr_name
1114 = initTcPrintErrors hsc_env iNTERACTIVE $
1115 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1116 lookup_rdr_name rdr_name
1118 lookup_rdr_name rdr_name = do {
1119 -- If the identifier is a constructor (begins with an
1120 -- upper-case letter), then we need to consider both
1121 -- constructor and type class identifiers.
1122 let { rdr_names = dataTcOccs rdr_name } ;
1124 -- results :: [Either Messages Name]
1125 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1127 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1128 -- The successful lookups will be (Just name)
1129 let { (warns_s, good_names) = unzip [ (msgs, name)
1130 | (msgs, Just name) <- results] ;
1131 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1133 -- Fail if nothing good happened, else add warnings
1134 if null good_names then
1135 -- No lookup succeeded, so
1136 -- pick the first error message and report it
1137 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1138 -- while the other is "X is not in scope",
1139 -- we definitely want the former; but we might pick the latter
1140 do { addMessages (head errs_s) ; failM }
1141 else -- Add deprecation warnings
1142 mapM_ addMessages warns_s ;
1148 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1149 tcRnLookupName hsc_env name
1150 = initTcPrintErrors hsc_env iNTERACTIVE $
1151 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1155 tcRnGetInfo :: HscEnv
1157 -> IO (Maybe (TyThing, Fixity, [Instance]))
1159 -- Used to implemnent :info in GHCi
1161 -- Look up a RdrName and return all the TyThings it might be
1162 -- A capitalised RdrName is given to us in the DataName namespace,
1163 -- but we want to treat it as *both* a data constructor
1164 -- *and* as a type or class constructor;
1165 -- hence the call to dataTcOccs, and we return up to two results
1166 tcRnGetInfo hsc_env name
1167 = initTcPrintErrors hsc_env iNTERACTIVE $
1168 let ictxt = hsc_IC hsc_env in
1169 setInteractiveContext hsc_env ictxt $ do
1171 -- Load the interface for all unqualified types and classes
1172 -- That way we will find all the instance declarations
1173 -- (Packages have not orphan modules, and we assume that
1174 -- in the home package all relevant modules are loaded.)
1175 loadUnqualIfaces ictxt
1177 thing <- tcLookupGlobal name
1178 fixity <- lookupFixityRn name
1179 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1180 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)))]