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, tcg_imports = imports })
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) }
502 | Just real_thing <- lookupTypeEnv local_type_env name
503 = do { let boot_decl = tyThingToIfaceDecl boot_thing
504 real_decl = tyThingToIfaceDecl real_thing
505 ; checkTc (checkBootDecl boot_decl real_decl)
506 (bootMisMatch boot_thing boot_decl real_decl) }
507 -- The easiest way to check compatibility is to convert to
508 -- iface syntax, where we already have good comparison functions
510 = addErrTc (missingBootThing boot_thing)
512 name = getName boot_thing
514 avail_env = imp_parent imports
515 is_implicit name = case lookupNameEnv avail_env name of
516 Just (AvailTC tc _) | tc /= name -> True
519 no_check name = isWiredInName name -- No checking for wired-in names. In particular,
520 -- 'error' is handled by a rather gross hack
521 -- (see comments in GHC.Err.hs-boot)
522 || name `elem` dfun_names
523 || is_implicit name -- Has a parent, which we'll check
525 dfun_names = map getName boot_insts
528 = case [dfun | inst <- local_insts,
529 let dfun = instanceDFunId inst,
530 idType dfun `tcEqType` boot_inst_ty ] of
531 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
532 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
534 boot_dfun = instanceDFunId boot_inst
535 boot_inst_ty = idType boot_dfun
536 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
539 missingBootThing thing
540 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
541 bootMisMatch thing boot_decl real_decl
542 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
543 ptext SLIT("Decl") <+> ppr real_decl,
544 ptext SLIT("Boot file:") <+> ppr boot_decl]
547 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
551 %************************************************************************
553 Type-checking the top level of a module
555 %************************************************************************
557 tcRnGroup takes a bunch of top-level source-code declarations, and
559 * gets supporting declarations from interface files
562 * and augments the TcGblEnv with the results
564 In Template Haskell it may be called repeatedly for each group of
565 declarations. It expects there to be an incoming TcGblEnv in the
566 monad; it augments it and returns the new TcGblEnv.
569 tcRnGroup :: ModDetails -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
570 -- Returns the variables free in the decls, for unused-binding reporting
571 tcRnGroup boot_details decls
572 = do { -- Rename the declarations
573 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
574 setGblEnv tcg_env $ do {
576 -- Typecheck the declarations
577 tcTopSrcDecls boot_details rn_decls
580 ------------------------------------------------
581 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
583 = do { -- Bring top level binders into scope
584 tcg_env <- importsFromLocalDecls group ;
585 setGblEnv tcg_env $ do {
587 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
589 -- Rename the source decls
590 (tcg_env, rn_decls) <- rnSrcDecls group ;
593 -- save the renamed syntax, if we want it
595 | Just grp <- tcg_rn_decls tcg_env
596 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
600 -- Dump trace of renaming part
601 rnDump (ppr rn_decls) ;
603 return (tcg_env', rn_decls)
606 ------------------------------------------------
607 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
608 tcTopSrcDecls boot_details
609 (HsGroup { hs_tyclds = tycl_decls,
610 hs_instds = inst_decls,
611 hs_derivds = deriv_decls,
612 hs_fords = foreign_decls,
613 hs_defds = default_decls,
614 hs_ruleds = rule_decls,
615 hs_valds = val_binds })
616 = do { -- Type-check the type and class decls, and all imported decls
617 -- The latter come in via tycl_decls
618 traceTc (text "Tc2") ;
620 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
621 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
622 -- an error we'd better stop now, to avoid a cascade
624 -- Make these type and class decls available to stuff slurped from interface files
625 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
628 setGblEnv tcg_env $ do {
629 -- Source-language instances, including derivings,
630 -- and import the supporting declarations
631 traceTc (text "Tc3") ;
632 (tcg_env, inst_infos, deriv_binds)
633 <- tcInstDecls1 tycl_decls inst_decls deriv_decls;
634 setGblEnv tcg_env $ do {
636 -- Foreign import declarations next. No zonking necessary
637 -- here; we can tuck them straight into the global environment.
638 traceTc (text "Tc4") ;
639 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
640 tcExtendGlobalValEnv fi_ids $ do {
642 -- Default declarations
643 traceTc (text "Tc4a") ;
644 default_tys <- tcDefaults default_decls ;
645 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
647 -- Value declarations next
648 -- We also typecheck any extra binds that came out
649 -- of the "deriving" process (deriv_binds)
650 traceTc (text "Tc5") ;
651 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
652 setLclTypeEnv tcl_env $ do {
654 -- Second pass over class and instance declarations,
655 traceTc (text "Tc6") ;
656 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
657 showLIE (text "after instDecls2") ;
660 -- They need to be zonked, so we return them
661 traceTc (text "Tc7") ;
662 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
665 rules <- tcRules rule_decls ;
668 traceTc (text "Tc7a") ;
669 tcg_env <- getGblEnv ;
670 let { all_binds = tc_val_binds `unionBags`
671 inst_binds `unionBags`
674 -- Extend the GblEnv with the (as yet un-zonked)
675 -- bindings, rules, foreign decls
676 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
677 tcg_rules = tcg_rules tcg_env ++ rules,
678 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
679 return (tcg_env', tcl_env)
684 %************************************************************************
688 %************************************************************************
691 checkMain :: TcM TcGblEnv
692 -- If we are in module Main, check that 'main' is defined.
694 = do { ghc_mode <- getGhcMode ;
695 tcg_env <- getGblEnv ;
697 let { main_mod = mainModIs dflags ;
698 main_fn = case mainFunIs dflags of {
699 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
700 Nothing -> main_RDR_Unqual } } ;
702 check_main ghc_mode tcg_env main_mod main_fn
706 check_main ghc_mode tcg_env main_mod main_fn
708 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
712 = addErrCtxt mainCtxt $
713 do { mb_main <- lookupSrcOcc_maybe main_fn
714 -- Check that 'main' is in scope
715 -- It might be imported from another module!
717 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
721 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
722 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
723 -- :Main.main :: IO () = runMainIO main
725 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
728 -- The function that the RTS invokes is always :Main.main,
729 -- which we call root_main_id.
730 -- (Because GHC allows the user to have a module not called
731 -- Main as the main module, we can't rely on the main function
732 -- being called "Main.main". That's why root_main_id has a fixed
734 -- We also make root_main_id an implicit Id, by making main_name
735 -- its parent (hence (Just main_name)). That has the effect
736 -- of preventing its type and unfolding from getting out into
737 -- the interface file. Otherwise we can end up with two defns
738 -- for 'main' in the interface file!
740 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
741 (mkVarOccFS FSLIT("main"))
742 (getSrcLoc main_name)
743 ; root_main_id = Id.mkExportedLocalId root_main_name ty
744 ; main_bind = noLoc (VarBind root_main_id main_expr) }
746 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
748 tcg_dus = tcg_dus tcg_env
749 `plusDU` usesOnly (unitFV main_name)
750 -- Record the use of 'main', so that we don't
751 -- complain about it being defined but not used
755 mod = tcg_mod tcg_env
757 complain_no_main | ghc_mode == Interactive = return ()
758 | otherwise = failWithTc noMainMsg
759 -- In interactive mode, don't worry about the absence of 'main'
760 -- In other modes, fail altogether, so that we don't go on
761 -- and complain a second time when processing the export list.
763 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
764 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
765 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
768 %*********************************************************
772 %*********************************************************
776 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
777 setInteractiveContext hsc_env icxt thing_inside
779 -- Initialise the tcg_inst_env with instances
780 -- from all home modules. This mimics the more selective
781 -- call to hptInstances in tcRnModule
782 dfuns = hptInstances hsc_env (\mod -> True)
784 updGblEnv (\env -> env {
785 tcg_rdr_env = ic_rn_gbl_env icxt,
786 tcg_type_env = ic_type_env icxt,
787 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
789 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
791 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
798 -> InteractiveContext
800 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
801 -- The returned [Name] is the same as the input except for
802 -- ExprStmt, in which case the returned [Name] is [itName]
804 -- The returned TypecheckedHsExpr is of type IO [ () ],
805 -- a list of the bound values, coerced to ().
807 tcRnStmt hsc_env ictxt rdr_stmt
808 = initTcPrintErrors hsc_env iNTERACTIVE $
809 setInteractiveContext hsc_env ictxt $ do {
811 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
812 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
813 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
816 -- The real work is done here
817 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
818 zonked_expr <- zonkTopLExpr tc_expr ;
819 zonked_ids <- zonkTopBndrs bound_ids ;
821 -- None of the Ids should be of unboxed type, because we
822 -- cast them all to HValues in the end!
823 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
825 traceTc (text "tcs 1") ;
826 let { -- (a) Make all the bound ids "global" ids, now that
827 -- they're notionally top-level bindings. This is
828 -- important: otherwise when we come to compile an expression
829 -- using these ids later, the byte code generator will consider
830 -- the occurrences to be free rather than global.
832 -- (b) Tidy their types; this is important, because :info may
833 -- ask to look at them, and :info expects the things it looks
834 -- up to have tidy types
835 global_ids = map globaliseAndTidy zonked_ids ;
837 -- Update the interactive context
838 rn_env = ic_rn_local_env ictxt ;
839 type_env = ic_type_env ictxt ;
841 bound_names = map idName global_ids ;
842 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
844 {- ---------------------------------------------
845 At one stage I removed any shadowed bindings from the type_env;
846 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
847 However, with Template Haskell they aren't necessarily inaccessible. Consider this
849 Prelude> let f n = n * 2 :: Int
850 Prelude> fName <- runQ [| f |]
851 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
853 Prelude> let f n = n * 3 :: Int
854 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
855 In the last line we use 'fName', which resolves to the *first* 'f'
856 in scope. If we delete it from the type env, GHCi crashes because
857 it doesn't expect that.
859 Hence this code is commented out
861 shadowed = [ n | name <- bound_names,
862 let rdr_name = mkRdrUnqual (nameOccName name),
863 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
864 filtered_type_env = delListFromNameEnv type_env shadowed ;
865 -------------------------------------------------- -}
867 new_type_env = extendTypeEnvWithIds type_env global_ids ;
868 new_ic = ictxt { ic_rn_local_env = new_rn_env,
869 ic_type_env = new_type_env }
872 dumpOptTcRn Opt_D_dump_tc
873 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
874 text "Typechecked expr" <+> ppr zonked_expr]) ;
876 returnM (new_ic, bound_names, zonked_expr)
879 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
880 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
882 globaliseAndTidy :: Id -> Id
884 -- Give the Id a Global Name, and tidy its type
885 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
887 tidy_type = tidyTopType (idType id)
890 Here is the grand plan, implemented in tcUserStmt
892 What you type The IO [HValue] that hscStmt returns
893 ------------- ------------------------------------
894 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
897 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
900 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
901 [NB: result not printed] bindings: [it]
903 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
904 result showable) bindings: [it]
906 expr (of non-IO type,
907 result not showable) ==> error
911 ---------------------------
912 type PlanResult = ([Id], LHsExpr Id)
913 type Plan = TcM PlanResult
915 runPlans :: [Plan] -> TcM PlanResult
916 -- Try the plans in order. If one fails (by raising an exn), try the next.
917 -- If one succeeds, take it.
918 runPlans [] = panic "runPlans"
920 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
923 mkPlan :: LStmt Name -> TcM PlanResult
924 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
925 = do { uniq <- newUnique -- is treated very specially
926 ; let fresh_it = itName uniq
927 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
928 matches = [mkMatch [] expr emptyLocalBinds]
929 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
930 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
931 (HsVar bindIOName) noSyntaxExpr
932 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
933 (HsVar thenIOName) placeHolderType
936 -- [it <- e; print it] but not if it::()
938 -- [let it = e; print it]
939 ; runPlans [ -- Plan A
940 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
941 ; it_ty <- zonkTcType (idType it_id)
942 ; ifM (isUnitTy it_ty) failM
945 -- Plan B; a naked bind statment
946 tcGhciStmts [bind_stmt],
948 -- Plan C; check that the let-binding is typeable all by itself.
949 -- If not, fail; if so, try to print it.
950 -- The two-step process avoids getting two errors: one from
951 -- the expression itself, and one from the 'print it' part
952 -- This two-step story is very clunky, alas
953 do { checkNoErrs (tcGhciStmts [let_stmt])
954 --- checkNoErrs defeats the error recovery of let-bindings
955 ; tcGhciStmts [let_stmt, print_it] }
958 mkPlan stmt@(L loc (BindStmt {}))
959 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
960 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
961 (HsVar thenIOName) placeHolderType
963 ; print_bind_result <- doptM Opt_PrintBindResult
964 ; let print_plan = do
965 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
966 ; v_ty <- zonkTcType (idType v_id)
967 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
971 -- [stmt; print v] but not if v::()
973 ; runPlans ((if print_bind_result then [print_plan] else []) ++
974 [tcGhciStmts [stmt]])
980 ---------------------------
981 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
983 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
984 ret_id <- tcLookupId returnIOName ; -- return @ IO
986 io_ty = mkTyConApp ioTyCon [] ;
987 ret_ty = mkListTy unitTy ;
988 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
989 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
990 (emptyRefinement, io_ret_ty) ;
992 names = map unLoc (collectLStmtsBinders stmts) ;
994 -- mk_return builds the expression
995 -- returnIO @ [()] [coerce () x, .., coerce () z]
997 -- Despite the inconvenience of building the type applications etc,
998 -- this *has* to be done in type-annotated post-typecheck form
999 -- because we are going to return a list of *polymorphic* values
1000 -- coerced to type (). If we built a *source* stmt
1001 -- return [coerce x, ..., coerce z]
1002 -- then the type checker would instantiate x..z, and we wouldn't
1003 -- get their *polymorphic* values. (And we'd get ambiguity errs
1004 -- if they were overloaded, since they aren't applied to anything.)
1005 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
1006 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1007 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1011 -- OK, we're ready to typecheck the stmts
1012 traceTc (text "tcs 2") ;
1013 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1014 mappM tcLookupId names ;
1015 -- Look up the names right in the middle,
1016 -- where they will all be in scope
1018 -- Simplify the context
1019 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1020 -- checkNoErrs ensures that the plan fails if context redn fails
1022 return (ids, mkHsDictLet const_binds $
1023 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1028 tcRnExpr just finds the type of an expression
1032 -> InteractiveContext
1035 tcRnExpr hsc_env ictxt rdr_expr
1036 = initTcPrintErrors hsc_env iNTERACTIVE $
1037 setInteractiveContext hsc_env ictxt $ do {
1039 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1042 -- Now typecheck the expression;
1043 -- it might have a rank-2 type (e.g. :t runST)
1044 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1045 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1046 tcSimplifyInteractive lie_top ;
1047 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
1049 let { all_expr_ty = mkForAllTys qtvs' $
1050 mkFunTys (map idType dict_ids) $
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
1097 = initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod)
1099 tcGetModuleExports :: Module -> TcM [AvailInfo]
1100 tcGetModuleExports mod = do
1101 let doc = ptext SLIT("context for compiling statements")
1102 iface <- initIfaceTcRn $ loadSysInterface doc mod
1103 loadOrphanModules (dep_orphs (mi_deps iface)) False
1104 -- Load any orphan-module interfaces,
1105 -- so their instances are visible
1106 loadOrphanModules (dep_finsts (mi_finsts iface)) True
1107 -- Load any family instance-module interfaces,
1108 -- so all family instances are visible
1109 ifaceExportNames (mi_exports iface)
1111 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1112 tcRnLookupRdrName hsc_env rdr_name
1113 = initTcPrintErrors hsc_env iNTERACTIVE $
1114 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1115 lookup_rdr_name rdr_name
1117 lookup_rdr_name rdr_name = do {
1118 -- If the identifier is a constructor (begins with an
1119 -- upper-case letter), then we need to consider both
1120 -- constructor and type class identifiers.
1121 let { rdr_names = dataTcOccs rdr_name } ;
1123 -- results :: [Either Messages Name]
1124 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1126 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1127 -- The successful lookups will be (Just name)
1128 let { (warns_s, good_names) = unzip [ (msgs, name)
1129 | (msgs, Just name) <- results] ;
1130 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1132 -- Fail if nothing good happened, else add warnings
1133 if null good_names then
1134 -- No lookup succeeded, so
1135 -- pick the first error message and report it
1136 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1137 -- while the other is "X is not in scope",
1138 -- we definitely want the former; but we might pick the latter
1139 do { addMessages (head errs_s) ; failM }
1140 else -- Add deprecation warnings
1141 mapM_ addMessages warns_s ;
1147 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1148 tcRnLookupName hsc_env name
1149 = initTcPrintErrors hsc_env iNTERACTIVE $
1150 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1154 tcRnGetInfo :: HscEnv
1156 -> IO (Maybe (TyThing, Fixity, [Instance]))
1158 -- Used to implemnent :info in GHCi
1160 -- Look up a RdrName and return all the TyThings it might be
1161 -- A capitalised RdrName is given to us in the DataName namespace,
1162 -- but we want to treat it as *both* a data constructor
1163 -- *and* as a type or class constructor;
1164 -- hence the call to dataTcOccs, and we return up to two results
1165 tcRnGetInfo hsc_env name
1166 = initTcPrintErrors hsc_env iNTERACTIVE $
1167 let ictxt = hsc_IC hsc_env in
1168 setInteractiveContext hsc_env ictxt $ do
1170 -- Load the interface for all unqualified types and classes
1171 -- That way we will find all the instance declarations
1172 -- (Packages have not orphan modules, and we assume that
1173 -- in the home package all relevant modules are loaded.)
1174 loadUnqualIfaces ictxt
1176 thing <- tcLookupGlobal name
1177 fixity <- lookupFixityRn name
1178 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1179 return (thing, fixity, ispecs)
1182 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1183 -- Filter the instances by the ones whose tycons (or clases resp)
1184 -- are in scope unqualified. Otherwise we list a whole lot too many!
1185 lookupInsts print_unqual (AClass cls)
1186 = do { inst_envs <- tcGetInstEnvs
1188 | ispec <- classInstances inst_envs cls
1189 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1191 lookupInsts print_unqual (ATyCon tc)
1192 = do { eps <- getEps -- Load all instances for all classes that are
1193 -- in the type environment (which are all the ones
1194 -- we've seen in any interface file so far)
1195 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1197 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1198 , let dfun = instanceDFunId ispec
1200 , plausibleDFun print_unqual dfun ] }
1202 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1203 tc_name = tyConName tc
1205 lookupInsts print_unqual other = return []
1207 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1208 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1210 ok name | isBuiltInSyntax name = True
1211 | isExternalName name =
1212 isNothing $ fst print_unqual (nameModule name)
1216 loadUnqualIfaces :: InteractiveContext -> TcM ()
1217 -- Load the home module for everything that is in scope unqualified
1218 -- This is so that we can accurately report the instances for
1220 loadUnqualIfaces ictxt
1222 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1224 unqual_mods = [ nameModule name
1225 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1226 let name = gre_name gre,
1227 not (isInternalName name),
1228 isTcOcc (nameOccName name), -- Types and classes only
1229 unQualOK gre ] -- In scope unqualified
1230 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1234 %************************************************************************
1238 %************************************************************************
1241 rnDump :: SDoc -> TcRn ()
1242 -- Dump, with a banner, if -ddump-rn
1243 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1245 tcDump :: TcGblEnv -> TcRn ()
1247 = do { dflags <- getDOpts ;
1249 -- Dump short output if -ddump-types or -ddump-tc
1250 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1251 (dumpTcRn short_dump) ;
1253 -- Dump bindings if -ddump-tc
1254 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1257 short_dump = pprTcGblEnv env
1258 full_dump = pprLHsBinds (tcg_binds env)
1259 -- NB: foreign x-d's have undefined's in their types;
1260 -- hence can't show the tc_fords
1263 = do { dflags <- getDOpts ;
1264 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1265 (dumpTcRn (pprModGuts mod_guts)) ;
1267 -- Dump bindings if -ddump-tc
1268 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1270 full_dump = pprCoreBindings (mg_binds mod_guts)
1272 -- It's unpleasant having both pprModGuts and pprModDetails here
1273 pprTcGblEnv :: TcGblEnv -> SDoc
1274 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1276 tcg_fam_insts = fam_insts,
1278 tcg_imports = imports })
1279 = vcat [ ppr_types insts type_env
1281 , ppr_fam_insts fam_insts
1282 , vcat (map ppr rules)
1283 , ppr_gen_tycons (typeEnvTyCons type_env)
1284 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1285 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1287 pprModGuts :: ModGuts -> SDoc
1288 pprModGuts (ModGuts { mg_types = type_env,
1290 = vcat [ ppr_types [] type_env,
1293 ppr_types :: [Instance] -> TypeEnv -> SDoc
1294 ppr_types insts type_env
1295 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1297 dfun_ids = map instanceDFunId insts
1298 ids = [id | id <- typeEnvIds type_env, want_sig id]
1299 want_sig id | opt_PprStyle_Debug = True
1300 | otherwise = isLocalId id &&
1301 isExternalName (idName id) &&
1302 not (id `elem` dfun_ids)
1303 -- isLocalId ignores data constructors, records selectors etc.
1304 -- The isExternalName ignores local dictionary and method bindings
1305 -- that the type checker has invented. Top-level user-defined things
1306 -- have External names.
1308 ppr_insts :: [Instance] -> SDoc
1309 ppr_insts [] = empty
1310 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1312 ppr_fam_insts :: [FamInst] -> SDoc
1313 ppr_fam_insts [] = empty
1314 ppr_fam_insts fam_insts =
1315 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1317 ppr_sigs :: [Var] -> SDoc
1319 -- Print type signatures; sort by OccName
1320 = vcat (map ppr_sig (sortLe le_sig ids))
1322 le_sig id1 id2 = getOccName id1 <= getOccName id2
1323 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1325 ppr_rules :: [CoreRule] -> SDoc
1326 ppr_rules [] = empty
1327 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1328 nest 4 (pprRules rs),
1331 ppr_gen_tycons [] = empty
1332 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1333 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]