2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
5 \section[TcModule]{Typechecking a whole module}
10 tcRnStmt, tcRnExpr, tcRnType,
22 #include "HsVersions.h"
26 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
88 import {- Kind parts of -} Type
97 import Control.Monad ( unless )
98 import Data.Maybe ( isJust )
103 %************************************************************************
105 Typecheck and rename a module
107 %************************************************************************
113 -> Bool -- True <=> save renamed syntax
114 -> Located (HsModule RdrName)
115 -> IO (Messages, Maybe TcGblEnv)
117 tcRnModule hsc_env hsc_src save_rn_syntax
118 (L loc (HsModule maybe_mod export_ies
119 import_decls local_decls mod_deprec _ module_info maybe_doc))
120 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
122 let { this_pkg = thisPackage (hsc_dflags hsc_env) ;
123 this_mod = case maybe_mod of
124 Nothing -> mAIN -- 'module M where' is omitted
125 Just (L _ mod) -> mkModule this_pkg mod } ;
128 initTc hsc_env hsc_src this_mod $
131 -- Deal with imports;
132 (rn_imports, rdr_env, imports) <- rnImports import_decls ;
134 let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)
135 ; dep_mods = imp_dep_mods imports
137 -- We want instance declarations from all home-package
138 -- modules below this one, including boot modules, except
139 -- ourselves. The 'except ourselves' is so that we don't
140 -- get the instances from this module's hs-boot file
141 ; want_instances :: ModuleName -> Bool
142 ; want_instances mod = mod `elemUFM` dep_mods
143 && mod /= moduleName this_mod
144 ; home_insts = hptInstances hsc_env want_instances
147 -- Record boot-file info in the EPS, so that it's
148 -- visible to loadHiBootInterface in tcRnSrcDecls,
149 -- and any other incrementally-performed imports
150 updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
152 -- Update the gbl env
154 gbl { tcg_rdr_env = plusOccEnv (tcg_rdr_env gbl) rdr_env,
155 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts,
156 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
157 tcg_rn_imports = if save_rn_syntax then
161 tcg_rn_decls = if save_rn_syntax then
167 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
168 -- Fail if there are any errors so far
169 -- The error printing (if needed) takes advantage
170 -- of the tcg_env we have now set
171 traceIf (text "rdr_env: " <+> ppr rdr_env) ;
174 -- Load any orphan-module and family instance-module
175 -- interfaces, so that their rules and instance decls will be
177 loadOrphanModules (imp_orphs imports) False ;
178 loadOrphanModules (imp_finsts imports) True ;
180 traceRn (text "rn1: checking family instance consistency") ;
181 let { directlyImpMods = map (\(mod, _, _) -> mod)
185 checkFamInstConsistency (imp_finsts imports) directlyImpMods ;
187 traceRn (text "rn1a") ;
188 -- Rename and type check the declarations
189 tcg_env <- if isHsBoot hsc_src then
190 tcRnHsBootDecls local_decls
192 tcRnSrcDecls local_decls ;
193 setGblEnv tcg_env $ do {
195 failIfErrsM ; -- reportDeprecations crashes sometimes
196 -- as a result of typechecker repairs (e.g. unboundNames)
197 traceRn (text "rn3") ;
199 -- Report the use of any deprecated things
200 -- We do this before processsing the export list so
201 -- that we don't bleat about re-exporting a deprecated
202 -- thing (especially via 'module Foo' export item)
203 -- Only uses in the body of the module are complained about
204 reportDeprecations (hsc_dflags hsc_env) tcg_env ;
206 -- Process the export list
207 (rn_exports, exports) <- rnExports (isJust maybe_mod) export_ies ;
209 traceRn (text "rn4") ;
211 -- Rename the Haddock documentation header
212 rn_module_doc <- rnMbHsDoc maybe_doc ;
214 -- Rename the Haddock module info
215 rn_description <- rnMbHsDoc (hmi_description module_info) ;
216 let { rn_module_info = module_info { hmi_description = rn_description } } ;
218 -- Check whether the entire module is deprecated
219 -- This happens only once per module
220 let { mod_deprecs = checkModDeprec mod_deprec } ;
222 -- Add exports and deprecations to envt
223 let { final_env = tcg_env { tcg_exports = exports,
224 tcg_rn_exports = if save_rn_syntax then
227 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly (availsToNameSet exports),
228 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
230 tcg_doc = rn_module_doc,
231 tcg_hmi = rn_module_info
233 -- A module deprecation over-rides the earlier ones
236 -- Report unused names
237 reportUnusedNames export_ies final_env ;
239 -- Dump output and return
246 %************************************************************************
248 Type-checking external-core modules
250 %************************************************************************
253 tcRnExtCore :: HscEnv
255 -> IO (Messages, Maybe ModGuts)
256 -- Nothing => some error occurred
258 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
259 -- The decls are IfaceDecls; all names are original names
260 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
262 initTc hsc_env ExtCoreFile this_mod $ do {
264 let { ldecls = map noLoc decls } ;
266 -- Deal with the type declarations; first bring their stuff
267 -- into scope, then rname them, then type check them
268 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
270 setGblEnv tcg_env $ do {
272 rn_decls <- rnTyClDecls ldecls ;
275 -- Dump trace of renaming part
276 rnDump (ppr rn_decls) ;
278 -- Typecheck them all together so that
279 -- any mutually recursive types are done right
280 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
281 -- Make the new type env available to stuff slurped from interface files
283 setGblEnv tcg_env $ do {
285 -- Now the core bindings
286 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
290 bndrs = bindersOfBinds core_binds ;
291 my_exports = map (Avail . idName) bndrs ;
292 -- ToDo: export the data types also?
294 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
296 mod_guts = ModGuts { mg_module = this_mod,
298 mg_usages = [], -- ToDo: compute usage
299 mg_dir_imps = [], -- ??
300 mg_deps = noDependencies, -- ??
301 mg_exports = my_exports,
302 mg_types = final_type_env,
303 mg_insts = tcg_insts tcg_env,
304 mg_fam_insts = tcg_fam_insts tcg_env,
305 mg_fam_inst_env = tcg_fam_inst_env tcg_env,
307 mg_binds = core_binds,
310 mg_rdr_env = emptyGlobalRdrEnv,
311 mg_fix_env = emptyFixityEnv,
312 mg_deprecs = NoDeprecs,
313 mg_foreign = NoStubs,
314 mg_hpc_info = noHpcInfo,
315 mg_dbg_sites = noDbgSites
318 tcCoreDump mod_guts ;
323 mkFakeGroup decls -- Rather clumsy; lots of unused fields
324 = emptyRdrGroup { hs_tyclds = decls }
328 %************************************************************************
330 Type-checking the top level of a module
332 %************************************************************************
335 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
336 -- Returns the variables free in the decls
337 -- Reason: solely to report unused imports and bindings
339 = do { -- Load the hi-boot interface for this module, if any
340 -- We do this now so that the boot_names can be passed
341 -- to tcTyAndClassDecls, because the boot_names are
342 -- automatically considered to be loop breakers
344 boot_iface <- tcHiBootIface mod ;
346 -- Do all the declarations
347 (tc_envs, lie) <- getLIE $ tc_rn_src_decls boot_iface decls ;
349 -- Finish simplifying class constraints
351 -- tcSimplifyTop deals with constant or ambiguous InstIds.
352 -- How could there be ambiguous ones? They can only arise if a
353 -- top-level decl falls under the monomorphism restriction
354 -- and no subsequent decl instantiates its type.
356 -- We do this after checkMain, so that we use the type info
357 -- thaat checkMain adds
359 -- We do it with both global and local env in scope:
360 -- * the global env exposes the instances to tcSimplifyTop
361 -- * the local env exposes the local Ids to tcSimplifyTop,
362 -- so that we get better error messages (monomorphism restriction)
363 traceTc (text "Tc8") ;
364 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
366 -- Backsubstitution. This must be done last.
367 -- Even tcSimplifyTop may do some unification.
368 traceTc (text "Tc9") ;
369 let { (tcg_env, _) = tc_envs
370 ; TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
371 tcg_rules = rules, tcg_fords = fords } = tcg_env
372 ; all_binds = binds `unionBags` inst_binds } ;
374 (bind_ids, binds', fords', rules') <- zonkTopDecls all_binds rules fords ;
376 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
377 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
380 tcg_fords = fords' } } ;
382 -- Make the new type env available to stuff slurped from interface files
383 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
385 -- Compare the hi-boot iface (if any) with the real thing
386 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
388 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
391 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
392 -- Loops around dealing with each top level inter-splice group
393 -- in turn, until it's dealt with the entire module
394 tc_rn_src_decls boot_details ds
395 = do { let { (first_group, group_tail) = findSplice ds } ;
396 -- If ds is [] we get ([], Nothing)
398 -- Deal with decls up to, but not including, the first splice
399 (tcg_env, rn_decls) <- checkNoErrs $ rnTopSrcDecls first_group ;
400 -- checkNoErrs: stop if renaming fails
402 (tcg_env, tcl_env) <- setGblEnv tcg_env $
403 tcTopSrcDecls boot_details rn_decls ;
405 -- If there is no splice, we're nearly done
406 setEnvs (tcg_env, tcl_env) $
408 Nothing -> do { tcg_env <- checkMain ; -- Check for `main'
409 return (tcg_env, tcl_env)
412 -- If there's a splice, we must carry on
413 Just (SpliceDecl splice_expr, rest_ds) -> do {
415 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
418 -- Rename the splice expression, and get its supporting decls
419 (rn_splice_expr, splice_fvs) <- checkNoErrs (rnLExpr splice_expr) ;
420 -- checkNoErrs: don't typecheck if renaming failed
421 rnDump (ppr rn_splice_expr) ;
423 -- Execute the splice
424 spliced_decls <- tcSpliceDecls rn_splice_expr ;
426 -- Glue them on the front of the remaining decls and loop
427 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
428 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
433 %************************************************************************
435 Compiling hs-boot source files, and
436 comparing the hi-boot interface with the real thing
438 %************************************************************************
441 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
442 tcRnHsBootDecls decls
443 = do { let { (first_group, group_tail) = findSplice decls }
446 Just stuff -> spliceInHsBootErr stuff
449 -- Rename the declarations
450 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
451 ; setGblEnv tcg_env $ do {
453 -- Todo: check no foreign decls, no rules, no default decls
455 -- Typecheck type/class decls
456 ; traceTc (text "Tc2")
457 ; let tycl_decls = hs_tyclds rn_group
458 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
459 ; setGblEnv tcg_env $ do {
461 -- Typecheck instance decls
462 ; traceTc (text "Tc3")
463 ; (tcg_env, inst_infos, _binds)
464 <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group)
465 ; setGblEnv tcg_env $ do {
467 -- Typecheck value declarations
468 ; traceTc (text "Tc5")
469 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
472 -- No simplification or zonking to do
473 ; traceTc (text "Tc7a")
474 ; gbl_env <- getGblEnv
476 -- Make the final type-env
477 -- Include the dfun_ids so that their type sigs
478 -- are written into the interface file
479 ; let { type_env0 = tcg_type_env gbl_env
480 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
481 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
482 ; dfun_ids = map iDFunId inst_infos }
483 ; return (gbl_env { tcg_type_env = type_env2 })
486 spliceInHsBootErr (SpliceDecl (L loc _), _)
487 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
490 Once we've typechecked the body of the module, we want to compare what
491 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
494 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
495 -- Compare the hi-boot file for this module (if there is one)
496 -- with the type environment we've just come up with
497 -- In the common case where there is no hi-boot file, the list
498 -- of boot_names is empty.
500 -- The bindings we return give bindings for the dfuns defined in the
501 -- hs-boot file, such as $fbEqT = $fEqT
504 (TcGblEnv { tcg_insts = local_insts, tcg_fam_insts = local_fam_insts,
505 tcg_type_env = local_type_env })
506 (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts,
507 md_types = boot_type_env })
508 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts)) ;
509 ; mapM_ check_one (typeEnvElts boot_type_env)
510 ; dfun_binds <- mapM check_inst boot_insts
511 ; unless (null boot_fam_insts) $
512 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
513 "instances in boot files yet...")
514 -- FIXME: Why? The actual comparison is not hard, but what would
515 -- be the equivalent to the dfun bindings returned for class
516 -- instances? We can't easily equate tycons...
517 ; return (unionManyBags dfun_binds) }
520 | isImplicitTyThing boot_thing = return ()
521 | name `elem` dfun_names = return ()
522 | isWiredInName name = return () -- No checking for wired-in names. In particular,
523 -- 'error' is handled by a rather gross hack
524 -- (see comments in GHC.Err.hs-boot)
525 | Just real_thing <- lookupTypeEnv local_type_env name
526 = do { let boot_decl = tyThingToIfaceDecl boot_thing
527 real_decl = tyThingToIfaceDecl real_thing
528 ; checkTc (checkBootDecl boot_decl real_decl)
529 (bootMisMatch boot_thing boot_decl real_decl) }
530 -- The easiest way to check compatibility is to convert to
531 -- iface syntax, where we already have good comparison functions
533 = addErrTc (missingBootThing boot_thing)
535 name = getName boot_thing
537 dfun_names = map getName boot_insts
540 = case [dfun | inst <- local_insts,
541 let dfun = instanceDFunId inst,
542 idType dfun `tcEqType` boot_inst_ty ] of
543 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
544 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
546 boot_dfun = instanceDFunId boot_inst
547 boot_inst_ty = idType boot_dfun
548 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
551 missingBootThing thing
552 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
553 bootMisMatch thing boot_decl real_decl
554 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
555 ptext SLIT("Decl") <+> ppr real_decl,
556 ptext SLIT("Boot file:") <+> ppr boot_decl]
559 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
563 %************************************************************************
565 Type-checking the top level of a module
567 %************************************************************************
569 tcRnGroup takes a bunch of top-level source-code declarations, and
571 * gets supporting declarations from interface files
574 * and augments the TcGblEnv with the results
576 In Template Haskell it may be called repeatedly for each group of
577 declarations. It expects there to be an incoming TcGblEnv in the
578 monad; it augments it and returns the new TcGblEnv.
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_insts, _), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1047 tcSimplifyInteractive lie_top ;
1049 let { all_expr_ty = mkForAllTys qtvs $
1050 mkFunTys (map (idType . instToId) dict_insts) $
1052 zonkTcType all_expr_ty
1055 smpl_doc = ptext SLIT("main expression")
1058 tcRnType just finds the kind of a type
1062 -> InteractiveContext
1065 tcRnType hsc_env ictxt rdr_type
1066 = initTcPrintErrors hsc_env iNTERACTIVE $
1067 setInteractiveContext hsc_env ictxt $ do {
1069 rn_type <- rnLHsType doc rdr_type ;
1072 -- Now kind-check the type
1073 (ty', kind) <- kcHsType rn_type ;
1077 doc = ptext SLIT("In GHCi input")
1083 %************************************************************************
1085 More GHCi stuff, to do with browsing and getting info
1087 %************************************************************************
1091 -- ASSUMES that the module is either in the HomePackageTable or is
1092 -- a package module with an interface on disk. If neither of these is
1093 -- true, then the result will be an error indicating the interface
1094 -- could not be found.
1095 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1096 getModuleExports hsc_env mod
1099 checkMods = ic_toplev_scope ic ++ ic_exports ic
1101 initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod checkMods)
1103 -- Get the export avail info and also load all orphan and family-instance
1104 -- modules. Finally, check that the family instances of all modules in the
1105 -- interactive context are consistent (these modules are in the second
1107 tcGetModuleExports :: Module -> [Module] -> TcM [AvailInfo]
1108 tcGetModuleExports mod directlyImpMods
1109 = do { let doc = ptext SLIT("context for compiling statements")
1110 ; iface <- initIfaceTcRn $ loadSysInterface doc mod
1112 -- Load any orphan-module and family instance-module
1113 -- interfaces, so their instances are visible.
1114 ; loadOrphanModules (dep_orphs (mi_deps iface)) False
1115 ; loadOrphanModules (dep_finsts (mi_deps iface)) True
1117 -- Check that the family instances of all directly loaded
1118 -- modules are consistent.
1119 ; checkFamInstConsistency (dep_finsts (mi_deps iface)) directlyImpMods
1121 ; ifaceExportNames (mi_exports iface)
1124 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1125 tcRnLookupRdrName hsc_env rdr_name
1126 = initTcPrintErrors hsc_env iNTERACTIVE $
1127 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1128 lookup_rdr_name rdr_name
1130 lookup_rdr_name rdr_name = do {
1131 -- If the identifier is a constructor (begins with an
1132 -- upper-case letter), then we need to consider both
1133 -- constructor and type class identifiers.
1134 let { rdr_names = dataTcOccs rdr_name } ;
1136 -- results :: [Either Messages Name]
1137 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1139 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1140 -- The successful lookups will be (Just name)
1141 let { (warns_s, good_names) = unzip [ (msgs, name)
1142 | (msgs, Just name) <- results] ;
1143 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1145 -- Fail if nothing good happened, else add warnings
1146 if null good_names then
1147 -- No lookup succeeded, so
1148 -- pick the first error message and report it
1149 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1150 -- while the other is "X is not in scope",
1151 -- we definitely want the former; but we might pick the latter
1152 do { addMessages (head errs_s) ; failM }
1153 else -- Add deprecation warnings
1154 mapM_ addMessages warns_s ;
1159 tcRnRecoverDataCon :: HscEnv -> a -> IO (Maybe DataCon)
1160 tcRnRecoverDataCon hsc_env a
1161 = initTcPrintErrors hsc_env iNTERACTIVE $
1162 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1163 do name <- recoverDataCon a
1164 tcLookupDataCon name
1166 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1167 tcRnLookupName hsc_env name
1168 = initTcPrintErrors hsc_env iNTERACTIVE $
1169 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1173 tcRnGetInfo :: HscEnv
1175 -> IO (Maybe (TyThing, Fixity, [Instance]))
1177 -- Used to implemnent :info in GHCi
1179 -- Look up a RdrName and return all the TyThings it might be
1180 -- A capitalised RdrName is given to us in the DataName namespace,
1181 -- but we want to treat it as *both* a data constructor
1182 -- *and* as a type or class constructor;
1183 -- hence the call to dataTcOccs, and we return up to two results
1184 tcRnGetInfo hsc_env name
1185 = initTcPrintErrors hsc_env iNTERACTIVE $
1186 let ictxt = hsc_IC hsc_env in
1187 setInteractiveContext hsc_env ictxt $ do
1189 -- Load the interface for all unqualified types and classes
1190 -- That way we will find all the instance declarations
1191 -- (Packages have not orphan modules, and we assume that
1192 -- in the home package all relevant modules are loaded.)
1193 loadUnqualIfaces ictxt
1195 thing <- tcLookupGlobal name
1196 fixity <- lookupFixityRn name
1197 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1198 return (thing, fixity, ispecs)
1200 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1201 -- Filter the instances by the ones whose tycons (or clases resp)
1202 -- are in scope unqualified. Otherwise we list a whole lot too many!
1203 lookupInsts print_unqual (AClass cls)
1204 = do { inst_envs <- tcGetInstEnvs
1206 | ispec <- classInstances inst_envs cls
1207 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1209 lookupInsts print_unqual (ATyCon tc)
1210 = do { eps <- getEps -- Load all instances for all classes that are
1211 -- in the type environment (which are all the ones
1212 -- we've seen in any interface file so far)
1213 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1215 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1216 , let dfun = instanceDFunId ispec
1218 , plausibleDFun print_unqual dfun ] }
1220 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1221 tc_name = tyConName tc
1223 lookupInsts print_unqual other = return []
1225 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1226 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1228 ok name | isBuiltInSyntax name = True
1229 | isExternalName name =
1230 isNothing $ fst print_unqual (nameModule name)
1234 loadUnqualIfaces :: InteractiveContext -> TcM ()
1235 -- Load the home module for everything that is in scope unqualified
1236 -- This is so that we can accurately report the instances for
1238 loadUnqualIfaces ictxt
1240 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1242 unqual_mods = [ nameModule name
1243 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1244 let name = gre_name gre,
1245 not (isInternalName name),
1246 isTcOcc (nameOccName name), -- Types and classes only
1247 unQualOK gre ] -- In scope unqualified
1248 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1252 %************************************************************************
1256 %************************************************************************
1259 rnDump :: SDoc -> TcRn ()
1260 -- Dump, with a banner, if -ddump-rn
1261 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1263 tcDump :: TcGblEnv -> TcRn ()
1265 = do { dflags <- getDOpts ;
1267 -- Dump short output if -ddump-types or -ddump-tc
1268 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1269 (dumpTcRn short_dump) ;
1271 -- Dump bindings if -ddump-tc
1272 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1275 short_dump = pprTcGblEnv env
1276 full_dump = pprLHsBinds (tcg_binds env)
1277 -- NB: foreign x-d's have undefined's in their types;
1278 -- hence can't show the tc_fords
1281 = do { dflags <- getDOpts ;
1282 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1283 (dumpTcRn (pprModGuts mod_guts)) ;
1285 -- Dump bindings if -ddump-tc
1286 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1288 full_dump = pprCoreBindings (mg_binds mod_guts)
1290 -- It's unpleasant having both pprModGuts and pprModDetails here
1291 pprTcGblEnv :: TcGblEnv -> SDoc
1292 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1294 tcg_fam_insts = fam_insts,
1296 tcg_imports = imports })
1297 = vcat [ ppr_types insts type_env
1298 , ppr_tycons fam_insts type_env
1300 , ppr_fam_insts fam_insts
1301 , vcat (map ppr rules)
1302 , ppr_gen_tycons (typeEnvTyCons type_env)
1303 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1304 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1306 pprModGuts :: ModGuts -> SDoc
1307 pprModGuts (ModGuts { mg_types = type_env,
1309 = vcat [ ppr_types [] type_env,
1312 ppr_types :: [Instance] -> TypeEnv -> SDoc
1313 ppr_types insts type_env
1314 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1316 dfun_ids = map instanceDFunId insts
1317 ids = [id | id <- typeEnvIds type_env, want_sig id]
1318 want_sig id | opt_PprStyle_Debug = True
1319 | otherwise = isLocalId id &&
1320 isExternalName (idName id) &&
1321 not (id `elem` dfun_ids)
1322 -- isLocalId ignores data constructors, records selectors etc.
1323 -- The isExternalName ignores local dictionary and method bindings
1324 -- that the type checker has invented. Top-level user-defined things
1325 -- have External names.
1327 ppr_tycons :: [FamInst] -> TypeEnv -> SDoc
1328 ppr_tycons fam_insts type_env
1329 = text "TYPE CONSTRUCTORS" $$ nest 4 (ppr_tydecls tycons)
1331 fi_tycons = map famInstTyCon fam_insts
1332 tycons = [tycon | tycon <- typeEnvTyCons type_env, want_tycon tycon]
1333 want_tycon tycon | opt_PprStyle_Debug = True
1334 | otherwise = not (isImplicitTyCon tycon) &&
1335 isExternalName (tyConName tycon) &&
1336 not (tycon `elem` fi_tycons)
1338 ppr_insts :: [Instance] -> SDoc
1339 ppr_insts [] = empty
1340 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1342 ppr_fam_insts :: [FamInst] -> SDoc
1343 ppr_fam_insts [] = empty
1344 ppr_fam_insts fam_insts =
1345 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1347 ppr_sigs :: [Var] -> SDoc
1349 -- Print type signatures; sort by OccName
1350 = vcat (map ppr_sig (sortLe le_sig ids))
1352 le_sig id1 id2 = getOccName id1 <= getOccName id2
1353 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1355 ppr_tydecls :: [TyCon] -> SDoc
1357 -- Print type constructor info; sort by OccName
1358 = vcat (map ppr_tycon (sortLe le_sig tycons))
1360 le_sig tycon1 tycon2 = getOccName tycon1 <= getOccName tycon2
1362 | isCoercionTyCon tycon = ptext SLIT("coercion") <+> ppr tycon
1363 | otherwise = ppr (tyThingToIfaceDecl (ATyCon tycon))
1365 ppr_rules :: [CoreRule] -> SDoc
1366 ppr_rules [] = empty
1367 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1368 nest 4 (pprRules rs),
1371 ppr_gen_tycons [] = empty
1372 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1373 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]