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 )
84 import {- Kind parts of -} Type
93 import Control.Monad ( unless )
94 import Data.Maybe ( isJust )
99 %************************************************************************
101 Typecheck and rename a module
103 %************************************************************************
109 -> Bool -- True <=> save renamed syntax
110 -> Located (HsModule RdrName)
111 -> IO (Messages, Maybe TcGblEnv)
113 tcRnModule hsc_env hsc_src save_rn_syntax
114 (L loc (HsModule maybe_mod export_ies
115 import_decls local_decls mod_deprec _ module_info maybe_doc))
116 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
118 let { this_pkg = thisPackage (hsc_dflags hsc_env) ;
119 this_mod = case maybe_mod of
120 Nothing -> mAIN -- 'module M where' is omitted
121 Just (L _ mod) -> mkModule this_pkg mod } ;
124 initTc hsc_env hsc_src this_mod $
127 -- Deal with imports;
128 (rn_imports, rdr_env, imports) <- rnImports import_decls ;
130 let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)
131 ; dep_mods = imp_dep_mods imports
133 -- We want instance declarations from all home-package
134 -- modules below this one, including boot modules, except
135 -- ourselves. The 'except ourselves' is so that we don't
136 -- get the instances from this module's hs-boot file
137 ; want_instances :: ModuleName -> Bool
138 ; want_instances mod = mod `elemUFM` dep_mods
139 && mod /= moduleName this_mod
140 ; home_insts = hptInstances hsc_env want_instances
143 -- Record boot-file info in the EPS, so that it's
144 -- visible to loadHiBootInterface in tcRnSrcDecls,
145 -- and any other incrementally-performed imports
146 updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
148 -- Update the gbl env
150 gbl { tcg_rdr_env = plusOccEnv (tcg_rdr_env gbl) rdr_env,
151 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts,
152 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
153 tcg_rn_imports = if save_rn_syntax then
157 tcg_rn_decls = if save_rn_syntax then
163 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
164 -- Fail if there are any errors so far
165 -- The error printing (if needed) takes advantage
166 -- of the tcg_env we have now set
167 traceIf (text "rdr_env: " <+> ppr rdr_env) ;
170 -- Load any orphan-module and family instance-module
171 -- interfaces, so that their rules and instance decls will be
173 loadOrphanModules (imp_orphs imports) False ;
174 loadOrphanModules (imp_finsts imports) True ;
176 traceRn (text "rn1a") ;
177 -- Rename and type check the declarations
178 tcg_env <- if isHsBoot hsc_src then
179 tcRnHsBootDecls local_decls
181 tcRnSrcDecls local_decls ;
182 setGblEnv tcg_env $ do {
184 traceRn (text "rn3") ;
186 -- Report the use of any deprecated things
187 -- We do this before processsing the export list so
188 -- that we don't bleat about re-exporting a deprecated
189 -- thing (especially via 'module Foo' export item)
190 -- Only uses in the body of the module are complained about
191 reportDeprecations (hsc_dflags hsc_env) tcg_env ;
193 -- Process the export list
194 (rn_exports, exports) <- rnExports (isJust maybe_mod) export_ies ;
196 -- Rename the Haddock documentation header
197 rn_module_doc <- rnMbHsDoc maybe_doc ;
199 -- Rename the Haddock module info
200 rn_description <- rnMbHsDoc (hmi_description module_info) ;
201 let { rn_module_info = module_info { hmi_description = rn_description } } ;
203 -- Check whether the entire module is deprecated
204 -- This happens only once per module
205 let { mod_deprecs = checkModDeprec mod_deprec } ;
207 -- Add exports and deprecations to envt
208 let { final_env = tcg_env { tcg_exports = exports,
209 tcg_rn_exports = if save_rn_syntax then
212 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly (availsToNameSet exports),
213 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
215 tcg_doc = rn_module_doc,
216 tcg_hmi = rn_module_info
218 -- A module deprecation over-rides the earlier ones
221 -- Report unused names
222 reportUnusedNames export_ies final_env ;
224 -- Dump output and return
231 %************************************************************************
233 Type-checking external-core modules
235 %************************************************************************
238 tcRnExtCore :: HscEnv
240 -> IO (Messages, Maybe ModGuts)
241 -- Nothing => some error occurred
243 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
244 -- The decls are IfaceDecls; all names are original names
245 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
247 initTc hsc_env ExtCoreFile this_mod $ do {
249 let { ldecls = map noLoc decls } ;
251 -- Deal with the type declarations; first bring their stuff
252 -- into scope, then rname them, then type check them
253 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
255 setGblEnv tcg_env $ do {
257 rn_decls <- rnTyClDecls ldecls ;
260 -- Dump trace of renaming part
261 rnDump (ppr rn_decls) ;
263 -- Typecheck them all together so that
264 -- any mutually recursive types are done right
265 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
266 -- Make the new type env available to stuff slurped from interface files
268 setGblEnv tcg_env $ do {
270 -- Now the core bindings
271 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
275 bndrs = bindersOfBinds core_binds ;
276 my_exports = map (Avail . idName) bndrs ;
277 -- ToDo: export the data types also?
279 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
281 mod_guts = ModGuts { mg_module = this_mod,
283 mg_usages = [], -- ToDo: compute usage
284 mg_dir_imps = [], -- ??
285 mg_deps = noDependencies, -- ??
286 mg_exports = my_exports,
287 mg_types = final_type_env,
288 mg_insts = tcg_insts tcg_env,
289 mg_fam_insts = tcg_fam_insts tcg_env,
291 mg_binds = core_binds,
294 mg_rdr_env = emptyGlobalRdrEnv,
295 mg_fix_env = emptyFixityEnv,
296 mg_deprecs = NoDeprecs,
300 tcCoreDump mod_guts ;
305 mkFakeGroup decls -- Rather clumsy; lots of unused fields
306 = emptyRdrGroup { hs_tyclds = decls }
310 %************************************************************************
312 Type-checking the top level of a module
314 %************************************************************************
317 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
318 -- Returns the variables free in the decls
319 -- Reason: solely to report unused imports and bindings
321 = do { -- Load the hi-boot interface for this module, if any
322 -- We do this now so that the boot_names can be passed
323 -- to tcTyAndClassDecls, because the boot_names are
324 -- automatically considered to be loop breakers
326 boot_iface <- tcHiBootIface mod ;
328 -- Do all the declarations
329 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_iface decls) ;
331 -- tcSimplifyTop deals with constant or ambiguous InstIds.
332 -- How could there be ambiguous ones? They can only arise if a
333 -- top-level decl falls under the monomorphism
334 -- restriction, and no subsequent decl instantiates its
335 -- type. (Usually, ambiguous type variables are resolved
336 -- during the generalisation step.)
337 traceTc (text "Tc8") ;
338 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
339 -- Setting the global env exposes the instances to tcSimplifyTop
340 -- Setting the local env exposes the local Ids to tcSimplifyTop,
341 -- so that we get better error messages (monomorphism restriction)
343 -- Backsubstitution. This must be done last.
344 -- Even tcSimplifyTop may do some unification.
345 traceTc (text "Tc9") ;
346 let { (tcg_env, _) = tc_envs ;
347 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
348 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
350 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
353 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
354 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
357 tcg_fords = fords' } } ;
359 -- Make the new type env available to stuff slurped from interface files
360 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
362 -- Compare the hi-boot iface (if any) with the real thing
363 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
365 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
368 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
369 -- Loops around dealing with each top level inter-splice group
370 -- in turn, until it's dealt with the entire module
371 tc_rn_src_decls boot_details ds
372 = do { let { (first_group, group_tail) = findSplice ds } ;
373 -- If ds is [] we get ([], Nothing)
375 -- Type check the decls up to, but not including, the first splice
376 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_details first_group ;
378 -- Bale out if errors; for example, error recovery when checking
379 -- the RHS of 'main' can mean that 'main' is not in the envt for
380 -- the subsequent checkMain test
385 -- If there is no splice, we're nearly done
387 Nothing -> do { -- Last thing: check for `main'
388 tcg_env <- checkMain ;
389 return (tcg_env, tcl_env)
392 -- If there's a splice, we must carry on
393 Just (SpliceDecl splice_expr, rest_ds) -> do {
395 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
398 -- Rename the splice expression, and get its supporting decls
399 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
400 failIfErrsM ; -- Don't typecheck if renaming failed
401 rnDump (ppr rn_splice_expr) ;
403 -- Execute the splice
404 spliced_decls <- tcSpliceDecls rn_splice_expr ;
406 -- Glue them on the front of the remaining decls and loop
407 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
408 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
413 %************************************************************************
415 Compiling hs-boot source files, and
416 comparing the hi-boot interface with the real thing
418 %************************************************************************
421 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
422 tcRnHsBootDecls decls
423 = do { let { (first_group, group_tail) = findSplice decls }
426 Just stuff -> spliceInHsBootErr stuff
429 -- Rename the declarations
430 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
431 ; setGblEnv tcg_env $ do {
433 -- Todo: check no foreign decls, no rules, no default decls
435 -- Typecheck type/class decls
436 ; traceTc (text "Tc2")
437 ; let tycl_decls = hs_tyclds rn_group
438 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
439 ; setGblEnv tcg_env $ do {
441 -- Typecheck instance decls
442 ; traceTc (text "Tc3")
443 ; (tcg_env, inst_infos, _binds)
444 <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group)
445 ; setGblEnv tcg_env $ do {
447 -- Typecheck value declarations
448 ; traceTc (text "Tc5")
449 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
452 -- No simplification or zonking to do
453 ; traceTc (text "Tc7a")
454 ; gbl_env <- getGblEnv
456 -- Make the final type-env
457 -- Include the dfun_ids so that their type sigs get
458 -- are written into the interface file
459 ; let { type_env0 = tcg_type_env gbl_env
460 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
461 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
462 ; dfun_ids = map iDFunId inst_infos }
463 ; return (gbl_env { tcg_type_env = type_env2 })
466 spliceInHsBootErr (SpliceDecl (L loc _), _)
467 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
470 Once we've typechecked the body of the module, we want to compare what
471 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
474 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
475 -- Compare the hi-boot file for this module (if there is one)
476 -- with the type environment we've just come up with
477 -- In the common case where there is no hi-boot file, the list
478 -- of boot_names is empty.
480 -- The bindings we return give bindings for the dfuns defined in the
481 -- hs-boot file, such as $fbEqT = $fEqT
484 (TcGblEnv { tcg_insts = local_insts, tcg_fam_insts = local_fam_insts,
485 tcg_type_env = local_type_env })
486 (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts,
487 md_types = boot_type_env })
488 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts)) ;
489 ; mapM_ check_one (typeEnvElts boot_type_env)
490 ; dfun_binds <- mapM check_inst boot_insts
491 ; unless (null boot_fam_insts) $
492 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
493 "instances in boot files yet...")
494 -- FIXME: Why? The actual comparison is not hard, but what would
495 -- be the equivalent to the dfun bindings returned for class
496 -- instances? We can't easily equate tycons...
497 ; return (unionManyBags dfun_binds) }
500 | isImplicitTyThing boot_thing = return ()
501 | name `elem` dfun_names = return ()
502 | isWiredInName name = return () -- No checking for wired-in names. In particular,
503 -- 'error' is handled by a rather gross hack
504 -- (see comments in GHC.Err.hs-boot)
505 | Just real_thing <- lookupTypeEnv local_type_env name
506 = do { let boot_decl = tyThingToIfaceDecl boot_thing
507 real_decl = tyThingToIfaceDecl real_thing
508 ; checkTc (checkBootDecl boot_decl real_decl)
509 (bootMisMatch boot_thing boot_decl real_decl) }
510 -- The easiest way to check compatibility is to convert to
511 -- iface syntax, where we already have good comparison functions
513 = addErrTc (missingBootThing boot_thing)
515 name = getName boot_thing
517 dfun_names = map getName boot_insts
520 = case [dfun | inst <- local_insts,
521 let dfun = instanceDFunId inst,
522 idType dfun `tcEqType` boot_inst_ty ] of
523 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
524 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
526 boot_dfun = instanceDFunId boot_inst
527 boot_inst_ty = idType boot_dfun
528 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
531 missingBootThing thing
532 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
533 bootMisMatch thing boot_decl real_decl
534 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
535 ptext SLIT("Decl") <+> ppr real_decl,
536 ptext SLIT("Boot file:") <+> ppr boot_decl]
539 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
543 %************************************************************************
545 Type-checking the top level of a module
547 %************************************************************************
549 tcRnGroup takes a bunch of top-level source-code declarations, and
551 * gets supporting declarations from interface files
554 * and augments the TcGblEnv with the results
556 In Template Haskell it may be called repeatedly for each group of
557 declarations. It expects there to be an incoming TcGblEnv in the
558 monad; it augments it and returns the new TcGblEnv.
561 tcRnGroup :: ModDetails -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
562 -- Returns the variables free in the decls, for unused-binding reporting
563 tcRnGroup boot_details decls
564 = do { -- Rename the declarations
565 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
566 setGblEnv tcg_env $ do {
568 -- Typecheck the declarations
569 tcTopSrcDecls boot_details rn_decls
572 ------------------------------------------------
573 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
575 = do { -- Bring top level binders into scope
576 tcg_env <- importsFromLocalDecls group ;
577 setGblEnv tcg_env $ do {
579 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
581 -- Rename the source decls
582 (tcg_env, rn_decls) <- rnSrcDecls group ;
585 -- save the renamed syntax, if we want it
587 | Just grp <- tcg_rn_decls tcg_env
588 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
592 -- Dump trace of renaming part
593 rnDump (ppr rn_decls) ;
595 return (tcg_env', rn_decls)
598 ------------------------------------------------
599 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
600 tcTopSrcDecls boot_details
601 (HsGroup { hs_tyclds = tycl_decls,
602 hs_instds = inst_decls,
603 hs_derivds = deriv_decls,
604 hs_fords = foreign_decls,
605 hs_defds = default_decls,
606 hs_ruleds = rule_decls,
607 hs_valds = val_binds })
608 = do { -- Type-check the type and class decls, and all imported decls
609 -- The latter come in via tycl_decls
610 traceTc (text "Tc2") ;
612 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
613 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
614 -- an error we'd better stop now, to avoid a cascade
616 -- Make these type and class decls available to stuff slurped from interface files
617 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
620 setGblEnv tcg_env $ do {
621 -- Source-language instances, including derivings,
622 -- and import the supporting declarations
623 traceTc (text "Tc3") ;
624 (tcg_env, inst_infos, deriv_binds)
625 <- tcInstDecls1 tycl_decls inst_decls deriv_decls;
626 setGblEnv tcg_env $ do {
628 -- Foreign import declarations next. No zonking necessary
629 -- here; we can tuck them straight into the global environment.
630 traceTc (text "Tc4") ;
631 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
632 tcExtendGlobalValEnv fi_ids $ do {
634 -- Default declarations
635 traceTc (text "Tc4a") ;
636 default_tys <- tcDefaults default_decls ;
637 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
639 -- Value declarations next
640 -- We also typecheck any extra binds that came out
641 -- of the "deriving" process (deriv_binds)
642 traceTc (text "Tc5") ;
643 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
644 setLclTypeEnv tcl_env $ do {
646 -- Second pass over class and instance declarations,
647 traceTc (text "Tc6") ;
648 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
649 showLIE (text "after instDecls2") ;
652 -- They need to be zonked, so we return them
653 traceTc (text "Tc7") ;
654 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
657 rules <- tcRules rule_decls ;
660 traceTc (text "Tc7a") ;
661 tcg_env <- getGblEnv ;
662 let { all_binds = tc_val_binds `unionBags`
663 inst_binds `unionBags`
666 -- Extend the GblEnv with the (as yet un-zonked)
667 -- bindings, rules, foreign decls
668 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
669 tcg_rules = tcg_rules tcg_env ++ rules,
670 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
671 return (tcg_env', tcl_env)
676 %************************************************************************
680 %************************************************************************
683 checkMain :: TcM TcGblEnv
684 -- If we are in module Main, check that 'main' is defined.
686 = do { ghc_mode <- getGhcMode ;
687 tcg_env <- getGblEnv ;
689 let { main_mod = mainModIs dflags ;
690 main_fn = case mainFunIs dflags of {
691 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
692 Nothing -> main_RDR_Unqual } } ;
694 check_main ghc_mode tcg_env main_mod main_fn
698 check_main ghc_mode tcg_env main_mod main_fn
700 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
704 = addErrCtxt mainCtxt $
705 do { mb_main <- lookupSrcOcc_maybe main_fn
706 -- Check that 'main' is in scope
707 -- It might be imported from another module!
709 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
713 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
714 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
715 -- :Main.main :: IO () = runMainIO main
717 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
720 -- The function that the RTS invokes is always :Main.main,
721 -- which we call root_main_id.
722 -- (Because GHC allows the user to have a module not called
723 -- Main as the main module, we can't rely on the main function
724 -- being called "Main.main". That's why root_main_id has a fixed
726 -- We also make root_main_id an implicit Id, by making main_name
727 -- its parent (hence (Just main_name)). That has the effect
728 -- of preventing its type and unfolding from getting out into
729 -- the interface file. Otherwise we can end up with two defns
730 -- for 'main' in the interface file!
732 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
733 (mkVarOccFS FSLIT("main"))
734 (getSrcLoc main_name)
735 ; root_main_id = Id.mkExportedLocalId root_main_name ty
736 ; main_bind = noLoc (VarBind root_main_id main_expr) }
738 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
740 tcg_dus = tcg_dus tcg_env
741 `plusDU` usesOnly (unitFV main_name)
742 -- Record the use of 'main', so that we don't
743 -- complain about it being defined but not used
747 mod = tcg_mod tcg_env
749 complain_no_main | ghc_mode == Interactive = return ()
750 | otherwise = failWithTc noMainMsg
751 -- In interactive mode, don't worry about the absence of 'main'
752 -- In other modes, fail altogether, so that we don't go on
753 -- and complain a second time when processing the export list.
755 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
756 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
757 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
760 %*********************************************************
764 %*********************************************************
768 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
769 setInteractiveContext hsc_env icxt thing_inside
771 -- Initialise the tcg_inst_env with instances
772 -- from all home modules. This mimics the more selective
773 -- call to hptInstances in tcRnModule
774 dfuns = hptInstances hsc_env (\mod -> True)
776 updGblEnv (\env -> env {
777 tcg_rdr_env = ic_rn_gbl_env icxt,
778 tcg_type_env = ic_type_env icxt,
779 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
781 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
783 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
790 -> InteractiveContext
792 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
793 -- The returned [Name] is the same as the input except for
794 -- ExprStmt, in which case the returned [Name] is [itName]
796 -- The returned TypecheckedHsExpr is of type IO [ () ],
797 -- a list of the bound values, coerced to ().
799 tcRnStmt hsc_env ictxt rdr_stmt
800 = initTcPrintErrors hsc_env iNTERACTIVE $
801 setInteractiveContext hsc_env ictxt $ do {
803 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
804 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
805 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
808 -- The real work is done here
809 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
810 zonked_expr <- zonkTopLExpr tc_expr ;
811 zonked_ids <- zonkTopBndrs bound_ids ;
813 -- None of the Ids should be of unboxed type, because we
814 -- cast them all to HValues in the end!
815 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
817 traceTc (text "tcs 1") ;
818 let { -- (a) Make all the bound ids "global" ids, now that
819 -- they're notionally top-level bindings. This is
820 -- important: otherwise when we come to compile an expression
821 -- using these ids later, the byte code generator will consider
822 -- the occurrences to be free rather than global.
824 -- (b) Tidy their types; this is important, because :info may
825 -- ask to look at them, and :info expects the things it looks
826 -- up to have tidy types
827 global_ids = map globaliseAndTidy zonked_ids ;
829 -- Update the interactive context
830 rn_env = ic_rn_local_env ictxt ;
831 type_env = ic_type_env ictxt ;
833 bound_names = map idName global_ids ;
834 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
836 {- ---------------------------------------------
837 At one stage I removed any shadowed bindings from the type_env;
838 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
839 However, with Template Haskell they aren't necessarily inaccessible. Consider this
841 Prelude> let f n = n * 2 :: Int
842 Prelude> fName <- runQ [| f |]
843 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
845 Prelude> let f n = n * 3 :: Int
846 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
847 In the last line we use 'fName', which resolves to the *first* 'f'
848 in scope. If we delete it from the type env, GHCi crashes because
849 it doesn't expect that.
851 Hence this code is commented out
853 shadowed = [ n | name <- bound_names,
854 let rdr_name = mkRdrUnqual (nameOccName name),
855 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
856 filtered_type_env = delListFromNameEnv type_env shadowed ;
857 -------------------------------------------------- -}
859 new_type_env = extendTypeEnvWithIds type_env global_ids ;
860 new_ic = ictxt { ic_rn_local_env = new_rn_env,
861 ic_type_env = new_type_env }
864 dumpOptTcRn Opt_D_dump_tc
865 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
866 text "Typechecked expr" <+> ppr zonked_expr]) ;
868 returnM (new_ic, bound_names, zonked_expr)
871 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
872 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
874 globaliseAndTidy :: Id -> Id
876 -- Give the Id a Global Name, and tidy its type
877 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
879 tidy_type = tidyTopType (idType id)
882 Here is the grand plan, implemented in tcUserStmt
884 What you type The IO [HValue] that hscStmt returns
885 ------------- ------------------------------------
886 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
889 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
892 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
893 [NB: result not printed] bindings: [it]
895 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
896 result showable) bindings: [it]
898 expr (of non-IO type,
899 result not showable) ==> error
903 ---------------------------
904 type PlanResult = ([Id], LHsExpr Id)
905 type Plan = TcM PlanResult
907 runPlans :: [Plan] -> TcM PlanResult
908 -- Try the plans in order. If one fails (by raising an exn), try the next.
909 -- If one succeeds, take it.
910 runPlans [] = panic "runPlans"
912 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
915 mkPlan :: LStmt Name -> TcM PlanResult
916 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
917 = do { uniq <- newUnique -- is treated very specially
918 ; let fresh_it = itName uniq
919 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
920 matches = [mkMatch [] expr emptyLocalBinds]
921 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
922 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
923 (HsVar bindIOName) noSyntaxExpr
924 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
925 (HsVar thenIOName) placeHolderType
928 -- [it <- e; print it] but not if it::()
930 -- [let it = e; print it]
931 ; runPlans [ -- Plan A
932 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
933 ; it_ty <- zonkTcType (idType it_id)
934 ; ifM (isUnitTy it_ty) failM
937 -- Plan B; a naked bind statment
938 tcGhciStmts [bind_stmt],
940 -- Plan C; check that the let-binding is typeable all by itself.
941 -- If not, fail; if so, try to print it.
942 -- The two-step process avoids getting two errors: one from
943 -- the expression itself, and one from the 'print it' part
944 -- This two-step story is very clunky, alas
945 do { checkNoErrs (tcGhciStmts [let_stmt])
946 --- checkNoErrs defeats the error recovery of let-bindings
947 ; tcGhciStmts [let_stmt, print_it] }
950 mkPlan stmt@(L loc (BindStmt {}))
951 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
952 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
953 (HsVar thenIOName) placeHolderType
955 ; print_bind_result <- doptM Opt_PrintBindResult
956 ; let print_plan = do
957 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
958 ; v_ty <- zonkTcType (idType v_id)
959 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
963 -- [stmt; print v] but not if v::()
965 ; runPlans ((if print_bind_result then [print_plan] else []) ++
966 [tcGhciStmts [stmt]])
972 ---------------------------
973 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
975 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
976 ret_id <- tcLookupId returnIOName ; -- return @ IO
978 io_ty = mkTyConApp ioTyCon [] ;
979 ret_ty = mkListTy unitTy ;
980 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
981 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
982 (emptyRefinement, io_ret_ty) ;
984 names = map unLoc (collectLStmtsBinders stmts) ;
986 -- mk_return builds the expression
987 -- returnIO @ [()] [coerce () x, .., coerce () z]
989 -- Despite the inconvenience of building the type applications etc,
990 -- this *has* to be done in type-annotated post-typecheck form
991 -- because we are going to return a list of *polymorphic* values
992 -- coerced to type (). If we built a *source* stmt
993 -- return [coerce x, ..., coerce z]
994 -- then the type checker would instantiate x..z, and we wouldn't
995 -- get their *polymorphic* values. (And we'd get ambiguity errs
996 -- if they were overloaded, since they aren't applied to anything.)
997 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
998 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
999 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1003 -- OK, we're ready to typecheck the stmts
1004 traceTc (text "tcs 2") ;
1005 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1006 mappM tcLookupId names ;
1007 -- Look up the names right in the middle,
1008 -- where they will all be in scope
1010 -- Simplify the context
1011 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1012 -- checkNoErrs ensures that the plan fails if context redn fails
1014 return (ids, mkHsDictLet const_binds $
1015 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1020 tcRnExpr just finds the type of an expression
1024 -> InteractiveContext
1027 tcRnExpr hsc_env ictxt rdr_expr
1028 = initTcPrintErrors hsc_env iNTERACTIVE $
1029 setInteractiveContext hsc_env ictxt $ do {
1031 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1034 -- Now typecheck the expression;
1035 -- it might have a rank-2 type (e.g. :t runST)
1036 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1037 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1038 tcSimplifyInteractive lie_top ;
1039 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
1041 let { all_expr_ty = mkForAllTys qtvs' $
1042 mkFunTys (map idType dict_ids) $
1044 zonkTcType all_expr_ty
1047 smpl_doc = ptext SLIT("main expression")
1050 tcRnType just finds the kind of a type
1054 -> InteractiveContext
1057 tcRnType hsc_env ictxt rdr_type
1058 = initTcPrintErrors hsc_env iNTERACTIVE $
1059 setInteractiveContext hsc_env ictxt $ do {
1061 rn_type <- rnLHsType doc rdr_type ;
1064 -- Now kind-check the type
1065 (ty', kind) <- kcHsType rn_type ;
1069 doc = ptext SLIT("In GHCi input")
1075 %************************************************************************
1077 More GHCi stuff, to do with browsing and getting info
1079 %************************************************************************
1083 -- ASSUMES that the module is either in the HomePackageTable or is
1084 -- a package module with an interface on disk. If neither of these is
1085 -- true, then the result will be an error indicating the interface
1086 -- could not be found.
1087 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1088 getModuleExports hsc_env mod
1089 = initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod)
1091 tcGetModuleExports :: Module -> TcM [AvailInfo]
1092 tcGetModuleExports mod = do
1093 let doc = ptext SLIT("context for compiling statements")
1094 iface <- initIfaceTcRn $ loadSysInterface doc mod
1095 loadOrphanModules (dep_orphs (mi_deps iface)) False
1096 -- Load any orphan-module interfaces,
1097 -- so their instances are visible
1098 loadOrphanModules (dep_finsts (mi_deps iface)) True
1099 -- Load any family instance-module interfaces,
1100 -- so all family instances are visible
1101 ifaceExportNames (mi_exports iface)
1103 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1104 tcRnLookupRdrName hsc_env rdr_name
1105 = initTcPrintErrors hsc_env iNTERACTIVE $
1106 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1107 lookup_rdr_name rdr_name
1109 lookup_rdr_name rdr_name = do {
1110 -- If the identifier is a constructor (begins with an
1111 -- upper-case letter), then we need to consider both
1112 -- constructor and type class identifiers.
1113 let { rdr_names = dataTcOccs rdr_name } ;
1115 -- results :: [Either Messages Name]
1116 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1118 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1119 -- The successful lookups will be (Just name)
1120 let { (warns_s, good_names) = unzip [ (msgs, name)
1121 | (msgs, Just name) <- results] ;
1122 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1124 -- Fail if nothing good happened, else add warnings
1125 if null good_names then
1126 -- No lookup succeeded, so
1127 -- pick the first error message and report it
1128 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1129 -- while the other is "X is not in scope",
1130 -- we definitely want the former; but we might pick the latter
1131 do { addMessages (head errs_s) ; failM }
1132 else -- Add deprecation warnings
1133 mapM_ addMessages warns_s ;
1139 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1140 tcRnLookupName hsc_env name
1141 = initTcPrintErrors hsc_env iNTERACTIVE $
1142 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1146 tcRnGetInfo :: HscEnv
1148 -> IO (Maybe (TyThing, Fixity, [Instance]))
1150 -- Used to implemnent :info in GHCi
1152 -- Look up a RdrName and return all the TyThings it might be
1153 -- A capitalised RdrName is given to us in the DataName namespace,
1154 -- but we want to treat it as *both* a data constructor
1155 -- *and* as a type or class constructor;
1156 -- hence the call to dataTcOccs, and we return up to two results
1157 tcRnGetInfo hsc_env name
1158 = initTcPrintErrors hsc_env iNTERACTIVE $
1159 let ictxt = hsc_IC hsc_env in
1160 setInteractiveContext hsc_env ictxt $ do
1162 -- Load the interface for all unqualified types and classes
1163 -- That way we will find all the instance declarations
1164 -- (Packages have not orphan modules, and we assume that
1165 -- in the home package all relevant modules are loaded.)
1166 loadUnqualIfaces ictxt
1168 thing <- tcLookupGlobal name
1169 fixity <- lookupFixityRn name
1170 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1171 return (thing, fixity, ispecs)
1174 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1175 -- Filter the instances by the ones whose tycons (or clases resp)
1176 -- are in scope unqualified. Otherwise we list a whole lot too many!
1177 lookupInsts print_unqual (AClass cls)
1178 = do { inst_envs <- tcGetInstEnvs
1180 | ispec <- classInstances inst_envs cls
1181 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1183 lookupInsts print_unqual (ATyCon tc)
1184 = do { eps <- getEps -- Load all instances for all classes that are
1185 -- in the type environment (which are all the ones
1186 -- we've seen in any interface file so far)
1187 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1189 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1190 , let dfun = instanceDFunId ispec
1192 , plausibleDFun print_unqual dfun ] }
1194 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1195 tc_name = tyConName tc
1197 lookupInsts print_unqual other = return []
1199 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1200 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1202 ok name | isBuiltInSyntax name = True
1203 | isExternalName name =
1204 isNothing $ fst print_unqual (nameModule name)
1208 loadUnqualIfaces :: InteractiveContext -> TcM ()
1209 -- Load the home module for everything that is in scope unqualified
1210 -- This is so that we can accurately report the instances for
1212 loadUnqualIfaces ictxt
1214 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1216 unqual_mods = [ nameModule name
1217 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1218 let name = gre_name gre,
1219 not (isInternalName name),
1220 isTcOcc (nameOccName name), -- Types and classes only
1221 unQualOK gre ] -- In scope unqualified
1222 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1226 %************************************************************************
1230 %************************************************************************
1233 rnDump :: SDoc -> TcRn ()
1234 -- Dump, with a banner, if -ddump-rn
1235 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1237 tcDump :: TcGblEnv -> TcRn ()
1239 = do { dflags <- getDOpts ;
1241 -- Dump short output if -ddump-types or -ddump-tc
1242 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1243 (dumpTcRn short_dump) ;
1245 -- Dump bindings if -ddump-tc
1246 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1249 short_dump = pprTcGblEnv env
1250 full_dump = pprLHsBinds (tcg_binds env)
1251 -- NB: foreign x-d's have undefined's in their types;
1252 -- hence can't show the tc_fords
1255 = do { dflags <- getDOpts ;
1256 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1257 (dumpTcRn (pprModGuts mod_guts)) ;
1259 -- Dump bindings if -ddump-tc
1260 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1262 full_dump = pprCoreBindings (mg_binds mod_guts)
1264 -- It's unpleasant having both pprModGuts and pprModDetails here
1265 pprTcGblEnv :: TcGblEnv -> SDoc
1266 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1268 tcg_fam_insts = fam_insts,
1270 tcg_imports = imports })
1271 = vcat [ ppr_types insts type_env
1273 , ppr_fam_insts fam_insts
1274 , vcat (map ppr rules)
1275 , ppr_gen_tycons (typeEnvTyCons type_env)
1276 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1277 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1279 pprModGuts :: ModGuts -> SDoc
1280 pprModGuts (ModGuts { mg_types = type_env,
1282 = vcat [ ppr_types [] type_env,
1285 ppr_types :: [Instance] -> TypeEnv -> SDoc
1286 ppr_types insts type_env
1287 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1289 dfun_ids = map instanceDFunId insts
1290 ids = [id | id <- typeEnvIds type_env, want_sig id]
1291 want_sig id | opt_PprStyle_Debug = True
1292 | otherwise = isLocalId id &&
1293 isExternalName (idName id) &&
1294 not (id `elem` dfun_ids)
1295 -- isLocalId ignores data constructors, records selectors etc.
1296 -- The isExternalName ignores local dictionary and method bindings
1297 -- that the type checker has invented. Top-level user-defined things
1298 -- have External names.
1300 ppr_insts :: [Instance] -> SDoc
1301 ppr_insts [] = empty
1302 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1304 ppr_fam_insts :: [FamInst] -> SDoc
1305 ppr_fam_insts [] = empty
1306 ppr_fam_insts fam_insts =
1307 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1309 ppr_sigs :: [Var] -> SDoc
1311 -- Print type signatures; sort by OccName
1312 = vcat (map ppr_sig (sortLe le_sig ids))
1314 le_sig id1 id2 = getOccName id1 <= getOccName id2
1315 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1317 ppr_rules :: [CoreRule] -> SDoc
1318 ppr_rules [] = empty
1319 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1320 nest 4 (pprRules rs),
1323 ppr_gen_tycons [] = empty
1324 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1325 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]