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,
306 mg_foreign = NoStubs,
307 mg_hpc_info = noHpcInfo
310 tcCoreDump mod_guts ;
315 mkFakeGroup decls -- Rather clumsy; lots of unused fields
316 = emptyRdrGroup { hs_tyclds = decls }
320 %************************************************************************
322 Type-checking the top level of a module
324 %************************************************************************
327 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
328 -- Returns the variables free in the decls
329 -- Reason: solely to report unused imports and bindings
331 = do { -- Load the hi-boot interface for this module, if any
332 -- We do this now so that the boot_names can be passed
333 -- to tcTyAndClassDecls, because the boot_names are
334 -- automatically considered to be loop breakers
336 boot_iface <- tcHiBootIface mod ;
338 -- Do all the declarations
339 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_iface decls) ;
341 -- tcSimplifyTop deals with constant or ambiguous InstIds.
342 -- How could there be ambiguous ones? They can only arise if a
343 -- top-level decl falls under the monomorphism
344 -- restriction, and no subsequent decl instantiates its
345 -- type. (Usually, ambiguous type variables are resolved
346 -- during the generalisation step.)
347 traceTc (text "Tc8") ;
348 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
349 -- Setting the global env exposes the instances to tcSimplifyTop
350 -- Setting the local env exposes the local Ids to tcSimplifyTop,
351 -- so that we get better error messages (monomorphism restriction)
353 -- Backsubstitution. This must be done last.
354 -- Even tcSimplifyTop may do some unification.
355 traceTc (text "Tc9") ;
356 let { (tcg_env, _) = tc_envs ;
357 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
358 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
360 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
363 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
364 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
367 tcg_fords = fords' } } ;
369 -- Make the new type env available to stuff slurped from interface files
370 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
372 -- Compare the hi-boot iface (if any) with the real thing
373 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
375 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
378 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
379 -- Loops around dealing with each top level inter-splice group
380 -- in turn, until it's dealt with the entire module
381 tc_rn_src_decls boot_details ds
382 = do { let { (first_group, group_tail) = findSplice ds } ;
383 -- If ds is [] we get ([], Nothing)
385 -- Type check the decls up to, but not including, the first splice
386 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_details first_group ;
388 -- Bale out if errors; for example, error recovery when checking
389 -- the RHS of 'main' can mean that 'main' is not in the envt for
390 -- the subsequent checkMain test
395 -- If there is no splice, we're nearly done
397 Nothing -> do { -- Last thing: check for `main'
398 tcg_env <- checkMain ;
399 return (tcg_env, tcl_env)
402 -- If there's a splice, we must carry on
403 Just (SpliceDecl splice_expr, rest_ds) -> do {
405 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
408 -- Rename the splice expression, and get its supporting decls
409 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
410 failIfErrsM ; -- Don't typecheck if renaming failed
411 rnDump (ppr rn_splice_expr) ;
413 -- Execute the splice
414 spliced_decls <- tcSpliceDecls rn_splice_expr ;
416 -- Glue them on the front of the remaining decls and loop
417 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
418 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
423 %************************************************************************
425 Compiling hs-boot source files, and
426 comparing the hi-boot interface with the real thing
428 %************************************************************************
431 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
432 tcRnHsBootDecls decls
433 = do { let { (first_group, group_tail) = findSplice decls }
436 Just stuff -> spliceInHsBootErr stuff
439 -- Rename the declarations
440 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
441 ; setGblEnv tcg_env $ do {
443 -- Todo: check no foreign decls, no rules, no default decls
445 -- Typecheck type/class decls
446 ; traceTc (text "Tc2")
447 ; let tycl_decls = hs_tyclds rn_group
448 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
449 ; setGblEnv tcg_env $ do {
451 -- Typecheck instance decls
452 ; traceTc (text "Tc3")
453 ; (tcg_env, inst_infos, _binds)
454 <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group)
455 ; setGblEnv tcg_env $ do {
457 -- Typecheck value declarations
458 ; traceTc (text "Tc5")
459 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
462 -- No simplification or zonking to do
463 ; traceTc (text "Tc7a")
464 ; gbl_env <- getGblEnv
466 -- Make the final type-env
467 -- Include the dfun_ids so that their type sigs
468 -- are written into the interface file
469 ; let { type_env0 = tcg_type_env gbl_env
470 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
471 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
472 ; dfun_ids = map iDFunId inst_infos }
473 ; return (gbl_env { tcg_type_env = type_env2 })
476 spliceInHsBootErr (SpliceDecl (L loc _), _)
477 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
480 Once we've typechecked the body of the module, we want to compare what
481 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
484 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
485 -- Compare the hi-boot file for this module (if there is one)
486 -- with the type environment we've just come up with
487 -- In the common case where there is no hi-boot file, the list
488 -- of boot_names is empty.
490 -- The bindings we return give bindings for the dfuns defined in the
491 -- hs-boot file, such as $fbEqT = $fEqT
494 (TcGblEnv { tcg_insts = local_insts, tcg_fam_insts = local_fam_insts,
495 tcg_type_env = local_type_env })
496 (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts,
497 md_types = boot_type_env })
498 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts)) ;
499 ; mapM_ check_one (typeEnvElts boot_type_env)
500 ; dfun_binds <- mapM check_inst boot_insts
501 ; unless (null boot_fam_insts) $
502 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
503 "instances in boot files yet...")
504 -- FIXME: Why? The actual comparison is not hard, but what would
505 -- be the equivalent to the dfun bindings returned for class
506 -- instances? We can't easily equate tycons...
507 ; return (unionManyBags dfun_binds) }
510 | isImplicitTyThing boot_thing = return ()
511 | name `elem` dfun_names = return ()
512 | isWiredInName name = return () -- No checking for wired-in names. In particular,
513 -- 'error' is handled by a rather gross hack
514 -- (see comments in GHC.Err.hs-boot)
515 | Just real_thing <- lookupTypeEnv local_type_env name
516 = do { let boot_decl = tyThingToIfaceDecl boot_thing
517 real_decl = tyThingToIfaceDecl real_thing
518 ; checkTc (checkBootDecl boot_decl real_decl)
519 (bootMisMatch boot_thing boot_decl real_decl) }
520 -- The easiest way to check compatibility is to convert to
521 -- iface syntax, where we already have good comparison functions
523 = addErrTc (missingBootThing boot_thing)
525 name = getName boot_thing
527 dfun_names = map getName boot_insts
530 = case [dfun | inst <- local_insts,
531 let dfun = instanceDFunId inst,
532 idType dfun `tcEqType` boot_inst_ty ] of
533 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
534 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
536 boot_dfun = instanceDFunId boot_inst
537 boot_inst_ty = idType boot_dfun
538 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
541 missingBootThing thing
542 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
543 bootMisMatch thing boot_decl real_decl
544 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
545 ptext SLIT("Decl") <+> ppr real_decl,
546 ptext SLIT("Boot file:") <+> ppr boot_decl]
549 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
553 %************************************************************************
555 Type-checking the top level of a module
557 %************************************************************************
559 tcRnGroup takes a bunch of top-level source-code declarations, and
561 * gets supporting declarations from interface files
564 * and augments the TcGblEnv with the results
566 In Template Haskell it may be called repeatedly for each group of
567 declarations. It expects there to be an incoming TcGblEnv in the
568 monad; it augments it and returns the new TcGblEnv.
571 tcRnGroup :: ModDetails -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
572 -- Returns the variables free in the decls, for unused-binding reporting
573 tcRnGroup boot_details decls
574 = do { -- Rename the declarations
575 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
576 setGblEnv tcg_env $ do {
578 -- Typecheck the declarations
579 tcTopSrcDecls boot_details rn_decls
582 ------------------------------------------------
583 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
585 = do { -- Bring top level binders into scope
586 tcg_env <- importsFromLocalDecls group ;
587 setGblEnv tcg_env $ do {
589 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
591 -- Rename the source decls
592 (tcg_env, rn_decls) <- rnSrcDecls group ;
595 -- save the renamed syntax, if we want it
597 | Just grp <- tcg_rn_decls tcg_env
598 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
602 -- Dump trace of renaming part
603 rnDump (ppr rn_decls) ;
605 return (tcg_env', rn_decls)
608 ------------------------------------------------
609 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
610 tcTopSrcDecls boot_details
611 (HsGroup { hs_tyclds = tycl_decls,
612 hs_instds = inst_decls,
613 hs_derivds = deriv_decls,
614 hs_fords = foreign_decls,
615 hs_defds = default_decls,
616 hs_ruleds = rule_decls,
617 hs_valds = val_binds })
618 = do { -- Type-check the type and class decls, and all imported decls
619 -- The latter come in via tycl_decls
620 traceTc (text "Tc2") ;
622 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
623 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
624 -- an error we'd better stop now, to avoid a cascade
626 -- Make these type and class decls available to stuff slurped from interface files
627 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
630 setGblEnv tcg_env $ do {
631 -- Source-language instances, including derivings,
632 -- and import the supporting declarations
633 traceTc (text "Tc3") ;
634 (tcg_env, inst_infos, deriv_binds)
635 <- tcInstDecls1 tycl_decls inst_decls deriv_decls;
636 setGblEnv tcg_env $ do {
638 -- Foreign import declarations next. No zonking necessary
639 -- here; we can tuck them straight into the global environment.
640 traceTc (text "Tc4") ;
641 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
642 tcExtendGlobalValEnv fi_ids $ do {
644 -- Default declarations
645 traceTc (text "Tc4a") ;
646 default_tys <- tcDefaults default_decls ;
647 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
649 -- Value declarations next
650 -- We also typecheck any extra binds that came out
651 -- of the "deriving" process (deriv_binds)
652 traceTc (text "Tc5") ;
653 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
654 setLclTypeEnv tcl_env $ do {
656 -- Second pass over class and instance declarations,
657 traceTc (text "Tc6") ;
658 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
659 showLIE (text "after instDecls2") ;
662 -- They need to be zonked, so we return them
663 traceTc (text "Tc7") ;
664 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
667 rules <- tcRules rule_decls ;
670 traceTc (text "Tc7a") ;
671 tcg_env <- getGblEnv ;
672 let { all_binds = tc_val_binds `unionBags`
673 inst_binds `unionBags`
676 -- Extend the GblEnv with the (as yet un-zonked)
677 -- bindings, rules, foreign decls
678 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
679 tcg_rules = tcg_rules tcg_env ++ rules,
680 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
681 return (tcg_env', tcl_env)
686 %************************************************************************
690 %************************************************************************
693 checkMain :: TcM TcGblEnv
694 -- If we are in module Main, check that 'main' is defined.
696 = do { ghc_mode <- getGhcMode ;
697 tcg_env <- getGblEnv ;
699 let { main_mod = mainModIs dflags ;
700 main_fn = case mainFunIs dflags of {
701 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
702 Nothing -> main_RDR_Unqual } } ;
704 check_main ghc_mode tcg_env main_mod main_fn
708 check_main ghc_mode tcg_env main_mod main_fn
710 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
714 = addErrCtxt mainCtxt $
715 do { mb_main <- lookupSrcOcc_maybe main_fn
716 -- Check that 'main' is in scope
717 -- It might be imported from another module!
719 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
723 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
724 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
725 -- :Main.main :: IO () = runMainIO main
727 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
730 -- The function that the RTS invokes is always :Main.main,
731 -- which we call root_main_id.
732 -- (Because GHC allows the user to have a module not called
733 -- Main as the main module, we can't rely on the main function
734 -- being called "Main.main". That's why root_main_id has a fixed
736 -- We also make root_main_id an implicit Id, by making main_name
737 -- its parent (hence (Just main_name)). That has the effect
738 -- of preventing its type and unfolding from getting out into
739 -- the interface file. Otherwise we can end up with two defns
740 -- for 'main' in the interface file!
742 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
743 (mkVarOccFS FSLIT("main"))
744 (getSrcLoc main_name)
745 ; root_main_id = Id.mkExportedLocalId root_main_name ty
746 ; main_bind = noLoc (VarBind root_main_id main_expr) }
748 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
750 tcg_dus = tcg_dus tcg_env
751 `plusDU` usesOnly (unitFV main_name)
752 -- Record the use of 'main', so that we don't
753 -- complain about it being defined but not used
757 mod = tcg_mod tcg_env
759 complain_no_main | ghc_mode == Interactive = return ()
760 | otherwise = failWithTc noMainMsg
761 -- In interactive mode, don't worry about the absence of 'main'
762 -- In other modes, fail altogether, so that we don't go on
763 -- and complain a second time when processing the export list.
765 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
766 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
767 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
770 %*********************************************************
774 %*********************************************************
778 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
779 setInteractiveContext hsc_env icxt thing_inside
781 -- Initialise the tcg_inst_env with instances
782 -- from all home modules. This mimics the more selective
783 -- call to hptInstances in tcRnModule
784 dfuns = hptInstances hsc_env (\mod -> True)
786 updGblEnv (\env -> env {
787 tcg_rdr_env = ic_rn_gbl_env icxt,
788 tcg_type_env = ic_type_env icxt,
789 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
791 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
793 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
800 -> InteractiveContext
802 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
803 -- The returned [Name] is the same as the input except for
804 -- ExprStmt, in which case the returned [Name] is [itName]
806 -- The returned TypecheckedHsExpr is of type IO [ () ],
807 -- a list of the bound values, coerced to ().
809 tcRnStmt hsc_env ictxt rdr_stmt
810 = initTcPrintErrors hsc_env iNTERACTIVE $
811 setInteractiveContext hsc_env ictxt $ do {
813 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
814 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
815 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
818 -- The real work is done here
819 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
820 zonked_expr <- zonkTopLExpr tc_expr ;
821 zonked_ids <- zonkTopBndrs bound_ids ;
823 -- None of the Ids should be of unboxed type, because we
824 -- cast them all to HValues in the end!
825 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
827 traceTc (text "tcs 1") ;
828 let { -- (a) Make all the bound ids "global" ids, now that
829 -- they're notionally top-level bindings. This is
830 -- important: otherwise when we come to compile an expression
831 -- using these ids later, the byte code generator will consider
832 -- the occurrences to be free rather than global.
834 -- (b) Tidy their types; this is important, because :info may
835 -- ask to look at them, and :info expects the things it looks
836 -- up to have tidy types
837 global_ids = map globaliseAndTidy zonked_ids ;
839 -- Update the interactive context
840 rn_env = ic_rn_local_env ictxt ;
841 type_env = ic_type_env ictxt ;
843 bound_names = map idName global_ids ;
844 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
846 {- ---------------------------------------------
847 At one stage I removed any shadowed bindings from the type_env;
848 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
849 However, with Template Haskell they aren't necessarily inaccessible. Consider this
851 Prelude> let f n = n * 2 :: Int
852 Prelude> fName <- runQ [| f |]
853 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
855 Prelude> let f n = n * 3 :: Int
856 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
857 In the last line we use 'fName', which resolves to the *first* 'f'
858 in scope. If we delete it from the type env, GHCi crashes because
859 it doesn't expect that.
861 Hence this code is commented out
863 shadowed = [ n | name <- bound_names,
864 let rdr_name = mkRdrUnqual (nameOccName name),
865 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
866 filtered_type_env = delListFromNameEnv type_env shadowed ;
867 -------------------------------------------------- -}
869 new_type_env = extendTypeEnvWithIds type_env global_ids ;
870 new_ic = ictxt { ic_rn_local_env = new_rn_env,
871 ic_type_env = new_type_env }
874 dumpOptTcRn Opt_D_dump_tc
875 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
876 text "Typechecked expr" <+> ppr zonked_expr]) ;
878 returnM (new_ic, bound_names, zonked_expr)
881 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
882 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
884 globaliseAndTidy :: Id -> Id
886 -- Give the Id a Global Name, and tidy its type
887 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
889 tidy_type = tidyTopType (idType id)
892 Here is the grand plan, implemented in tcUserStmt
894 What you type The IO [HValue] that hscStmt returns
895 ------------- ------------------------------------
896 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
899 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
902 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
903 [NB: result not printed] bindings: [it]
905 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
906 result showable) bindings: [it]
908 expr (of non-IO type,
909 result not showable) ==> error
913 ---------------------------
914 type PlanResult = ([Id], LHsExpr Id)
915 type Plan = TcM PlanResult
917 runPlans :: [Plan] -> TcM PlanResult
918 -- Try the plans in order. If one fails (by raising an exn), try the next.
919 -- If one succeeds, take it.
920 runPlans [] = panic "runPlans"
922 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
925 mkPlan :: LStmt Name -> TcM PlanResult
926 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
927 = do { uniq <- newUnique -- is treated very specially
928 ; let fresh_it = itName uniq
929 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
930 matches = [mkMatch [] expr emptyLocalBinds]
931 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
932 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
933 (HsVar bindIOName) noSyntaxExpr
934 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
935 (HsVar thenIOName) placeHolderType
938 -- [it <- e; print it] but not if it::()
940 -- [let it = e; print it]
941 ; runPlans [ -- Plan A
942 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
943 ; it_ty <- zonkTcType (idType it_id)
944 ; ifM (isUnitTy it_ty) failM
947 -- Plan B; a naked bind statment
948 tcGhciStmts [bind_stmt],
950 -- Plan C; check that the let-binding is typeable all by itself.
951 -- If not, fail; if so, try to print it.
952 -- The two-step process avoids getting two errors: one from
953 -- the expression itself, and one from the 'print it' part
954 -- This two-step story is very clunky, alas
955 do { checkNoErrs (tcGhciStmts [let_stmt])
956 --- checkNoErrs defeats the error recovery of let-bindings
957 ; tcGhciStmts [let_stmt, print_it] }
960 mkPlan stmt@(L loc (BindStmt {}))
961 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
962 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
963 (HsVar thenIOName) placeHolderType
965 ; print_bind_result <- doptM Opt_PrintBindResult
966 ; let print_plan = do
967 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
968 ; v_ty <- zonkTcType (idType v_id)
969 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
973 -- [stmt; print v] but not if v::()
975 ; runPlans ((if print_bind_result then [print_plan] else []) ++
976 [tcGhciStmts [stmt]])
982 ---------------------------
983 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
985 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
986 ret_id <- tcLookupId returnIOName ; -- return @ IO
988 io_ty = mkTyConApp ioTyCon [] ;
989 ret_ty = mkListTy unitTy ;
990 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
991 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
992 (emptyRefinement, io_ret_ty) ;
994 names = map unLoc (collectLStmtsBinders stmts) ;
996 -- mk_return builds the expression
997 -- returnIO @ [()] [coerce () x, .., coerce () z]
999 -- Despite the inconvenience of building the type applications etc,
1000 -- this *has* to be done in type-annotated post-typecheck form
1001 -- because we are going to return a list of *polymorphic* values
1002 -- coerced to type (). If we built a *source* stmt
1003 -- return [coerce x, ..., coerce z]
1004 -- then the type checker would instantiate x..z, and we wouldn't
1005 -- get their *polymorphic* values. (And we'd get ambiguity errs
1006 -- if they were overloaded, since they aren't applied to anything.)
1007 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
1008 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1009 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1013 -- OK, we're ready to typecheck the stmts
1014 traceTc (text "tcs 2") ;
1015 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1016 mappM tcLookupId names ;
1017 -- Look up the names right in the middle,
1018 -- where they will all be in scope
1020 -- Simplify the context
1021 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1022 -- checkNoErrs ensures that the plan fails if context redn fails
1024 return (ids, mkHsDictLet const_binds $
1025 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1030 tcRnExpr just finds the type of an expression
1034 -> InteractiveContext
1037 tcRnExpr hsc_env ictxt rdr_expr
1038 = initTcPrintErrors hsc_env iNTERACTIVE $
1039 setInteractiveContext hsc_env ictxt $ do {
1041 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1044 -- Now typecheck the expression;
1045 -- it might have a rank-2 type (e.g. :t runST)
1046 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1047 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1048 tcSimplifyInteractive lie_top ;
1049 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
1051 let { all_expr_ty = mkForAllTys qtvs' $
1052 mkFunTys (map idType dict_ids) $
1054 zonkTcType all_expr_ty
1057 smpl_doc = ptext SLIT("main expression")
1060 tcRnType just finds the kind of a type
1064 -> InteractiveContext
1067 tcRnType hsc_env ictxt rdr_type
1068 = initTcPrintErrors hsc_env iNTERACTIVE $
1069 setInteractiveContext hsc_env ictxt $ do {
1071 rn_type <- rnLHsType doc rdr_type ;
1074 -- Now kind-check the type
1075 (ty', kind) <- kcHsType rn_type ;
1079 doc = ptext SLIT("In GHCi input")
1085 %************************************************************************
1087 More GHCi stuff, to do with browsing and getting info
1089 %************************************************************************
1093 -- ASSUMES that the module is either in the HomePackageTable or is
1094 -- a package module with an interface on disk. If neither of these is
1095 -- true, then the result will be an error indicating the interface
1096 -- could not be found.
1097 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1098 getModuleExports hsc_env mod
1099 = initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod)
1101 tcGetModuleExports :: Module -> TcM [AvailInfo]
1102 tcGetModuleExports mod = do
1103 let doc = ptext SLIT("context for compiling statements")
1104 iface <- initIfaceTcRn $ loadSysInterface doc mod
1105 loadOrphanModules (dep_orphs (mi_deps iface)) False
1106 -- Load any orphan-module interfaces,
1107 -- so their instances are visible
1108 loadOrphanModules (dep_finsts (mi_deps iface)) True
1109 -- Load any family instance-module interfaces,
1110 -- so all family instances are visible
1111 ifaceExportNames (mi_exports iface)
1113 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1114 tcRnLookupRdrName hsc_env rdr_name
1115 = initTcPrintErrors hsc_env iNTERACTIVE $
1116 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1117 lookup_rdr_name rdr_name
1119 lookup_rdr_name rdr_name = do {
1120 -- If the identifier is a constructor (begins with an
1121 -- upper-case letter), then we need to consider both
1122 -- constructor and type class identifiers.
1123 let { rdr_names = dataTcOccs rdr_name } ;
1125 -- results :: [Either Messages Name]
1126 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1128 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1129 -- The successful lookups will be (Just name)
1130 let { (warns_s, good_names) = unzip [ (msgs, name)
1131 | (msgs, Just name) <- results] ;
1132 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1134 -- Fail if nothing good happened, else add warnings
1135 if null good_names then
1136 -- No lookup succeeded, so
1137 -- pick the first error message and report it
1138 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1139 -- while the other is "X is not in scope",
1140 -- we definitely want the former; but we might pick the latter
1141 do { addMessages (head errs_s) ; failM }
1142 else -- Add deprecation warnings
1143 mapM_ addMessages warns_s ;
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)
1184 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1185 -- Filter the instances by the ones whose tycons (or clases resp)
1186 -- are in scope unqualified. Otherwise we list a whole lot too many!
1187 lookupInsts print_unqual (AClass cls)
1188 = do { inst_envs <- tcGetInstEnvs
1190 | ispec <- classInstances inst_envs cls
1191 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1193 lookupInsts print_unqual (ATyCon tc)
1194 = do { eps <- getEps -- Load all instances for all classes that are
1195 -- in the type environment (which are all the ones
1196 -- we've seen in any interface file so far)
1197 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1199 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1200 , let dfun = instanceDFunId ispec
1202 , plausibleDFun print_unqual dfun ] }
1204 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1205 tc_name = tyConName tc
1207 lookupInsts print_unqual other = return []
1209 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1210 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1212 ok name | isBuiltInSyntax name = True
1213 | isExternalName name =
1214 isNothing $ fst print_unqual (nameModule name)
1218 loadUnqualIfaces :: InteractiveContext -> TcM ()
1219 -- Load the home module for everything that is in scope unqualified
1220 -- This is so that we can accurately report the instances for
1222 loadUnqualIfaces ictxt
1224 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1226 unqual_mods = [ nameModule name
1227 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1228 let name = gre_name gre,
1229 not (isInternalName name),
1230 isTcOcc (nameOccName name), -- Types and classes only
1231 unQualOK gre ] -- In scope unqualified
1232 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1236 %************************************************************************
1240 %************************************************************************
1243 rnDump :: SDoc -> TcRn ()
1244 -- Dump, with a banner, if -ddump-rn
1245 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1247 tcDump :: TcGblEnv -> TcRn ()
1249 = do { dflags <- getDOpts ;
1251 -- Dump short output if -ddump-types or -ddump-tc
1252 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1253 (dumpTcRn short_dump) ;
1255 -- Dump bindings if -ddump-tc
1256 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1259 short_dump = pprTcGblEnv env
1260 full_dump = pprLHsBinds (tcg_binds env)
1261 -- NB: foreign x-d's have undefined's in their types;
1262 -- hence can't show the tc_fords
1265 = do { dflags <- getDOpts ;
1266 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1267 (dumpTcRn (pprModGuts mod_guts)) ;
1269 -- Dump bindings if -ddump-tc
1270 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1272 full_dump = pprCoreBindings (mg_binds mod_guts)
1274 -- It's unpleasant having both pprModGuts and pprModDetails here
1275 pprTcGblEnv :: TcGblEnv -> SDoc
1276 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1278 tcg_fam_insts = fam_insts,
1280 tcg_imports = imports })
1281 = vcat [ ppr_types insts type_env
1282 , ppr_tycons fam_insts type_env
1284 , ppr_fam_insts fam_insts
1285 , vcat (map ppr rules)
1286 , ppr_gen_tycons (typeEnvTyCons type_env)
1287 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1288 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1290 pprModGuts :: ModGuts -> SDoc
1291 pprModGuts (ModGuts { mg_types = type_env,
1293 = vcat [ ppr_types [] type_env,
1296 ppr_types :: [Instance] -> TypeEnv -> SDoc
1297 ppr_types insts type_env
1298 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1300 dfun_ids = map instanceDFunId insts
1301 ids = [id | id <- typeEnvIds type_env, want_sig id]
1302 want_sig id | opt_PprStyle_Debug = True
1303 | otherwise = isLocalId id &&
1304 isExternalName (idName id) &&
1305 not (id `elem` dfun_ids)
1306 -- isLocalId ignores data constructors, records selectors etc.
1307 -- The isExternalName ignores local dictionary and method bindings
1308 -- that the type checker has invented. Top-level user-defined things
1309 -- have External names.
1311 ppr_tycons :: [FamInst] -> TypeEnv -> SDoc
1312 ppr_tycons fam_insts type_env
1313 = text "TYPE CONSTRUCTORS" $$ nest 4 (ppr_tydecls tycons)
1315 fi_tycons = map famInstTyCon fam_insts
1316 tycons = [tycon | tycon <- typeEnvTyCons type_env, want_tycon tycon]
1317 want_tycon tycon | opt_PprStyle_Debug = True
1318 | otherwise = not (isImplicitTyCon tycon) &&
1319 isExternalName (tyConName tycon) &&
1320 not (tycon `elem` fi_tycons)
1322 ppr_insts :: [Instance] -> SDoc
1323 ppr_insts [] = empty
1324 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1326 ppr_fam_insts :: [FamInst] -> SDoc
1327 ppr_fam_insts [] = empty
1328 ppr_fam_insts fam_insts =
1329 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1331 ppr_sigs :: [Var] -> SDoc
1333 -- Print type signatures; sort by OccName
1334 = vcat (map ppr_sig (sortLe le_sig ids))
1336 le_sig id1 id2 = getOccName id1 <= getOccName id2
1337 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1339 ppr_tydecls :: [TyCon] -> SDoc
1341 -- Print type constructor info; sort by OccName
1342 = vcat (map ppr_tycon (sortLe le_sig tycons))
1344 le_sig tycon1 tycon2 = getOccName tycon1 <= getOccName tycon2
1346 | isCoercionTyCon tycon = ptext SLIT("coercion") <+> ppr tycon
1347 | otherwise = ppr (tyThingToIfaceDecl (ATyCon tycon))
1349 ppr_rules :: [CoreRule] -> SDoc
1350 ppr_rules [] = empty
1351 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1352 nest 4 (pprRules rs),
1355 ppr_gen_tycons [] = empty
1356 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1357 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]