2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
5 \section[TcModule]{Typechecking a whole module}
10 tcRnStmt, tcRnExpr, tcRnType,
21 #include "HsVersions.h"
25 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
85 import {- Kind parts of -} Type
94 import Control.Monad ( unless )
95 import Data.Maybe ( isJust )
100 %************************************************************************
102 Typecheck and rename a module
104 %************************************************************************
110 -> Bool -- True <=> save renamed syntax
111 -> Located (HsModule RdrName)
112 -> IO (Messages, Maybe TcGblEnv)
114 tcRnModule hsc_env hsc_src save_rn_syntax
115 (L loc (HsModule maybe_mod export_ies
116 import_decls local_decls mod_deprec _ module_info maybe_doc))
117 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
119 let { this_pkg = thisPackage (hsc_dflags hsc_env) ;
120 this_mod = case maybe_mod of
121 Nothing -> mAIN -- 'module M where' is omitted
122 Just (L _ mod) -> mkModule this_pkg mod } ;
125 initTc hsc_env hsc_src this_mod $
128 -- Deal with imports;
129 (rn_imports, rdr_env, imports) <- rnImports import_decls ;
131 let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)
132 ; dep_mods = imp_dep_mods imports
134 -- We want instance declarations from all home-package
135 -- modules below this one, including boot modules, except
136 -- ourselves. The 'except ourselves' is so that we don't
137 -- get the instances from this module's hs-boot file
138 ; want_instances :: ModuleName -> Bool
139 ; want_instances mod = mod `elemUFM` dep_mods
140 && mod /= moduleName this_mod
141 ; home_insts = hptInstances hsc_env want_instances
144 -- Record boot-file info in the EPS, so that it's
145 -- visible to loadHiBootInterface in tcRnSrcDecls,
146 -- and any other incrementally-performed imports
147 updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
149 -- Update the gbl env
151 gbl { tcg_rdr_env = plusOccEnv (tcg_rdr_env gbl) rdr_env,
152 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts,
153 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
154 tcg_rn_imports = if save_rn_syntax then
158 tcg_rn_decls = if save_rn_syntax then
164 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
165 -- Fail if there are any errors so far
166 -- The error printing (if needed) takes advantage
167 -- of the tcg_env we have now set
168 traceIf (text "rdr_env: " <+> ppr rdr_env) ;
171 -- Load any orphan-module and family instance-module
172 -- interfaces, so that their rules and instance decls will be
174 loadOrphanModules (imp_orphs imports) False ;
175 loadOrphanModules (imp_finsts imports) True ;
177 let { directlyImpMods = map (\(mod, _, _) -> mod)
181 checkFamInstConsistency (imp_finsts imports) directlyImpMods ;
183 traceRn (text "rn1a") ;
184 -- Rename and type check the declarations
185 tcg_env <- if isHsBoot hsc_src then
186 tcRnHsBootDecls local_decls
188 tcRnSrcDecls local_decls ;
189 setGblEnv tcg_env $ do {
191 traceRn (text "rn3") ;
193 -- Report the use of any deprecated things
194 -- We do this before processsing the export list so
195 -- that we don't bleat about re-exporting a deprecated
196 -- thing (especially via 'module Foo' export item)
197 -- Only uses in the body of the module are complained about
198 reportDeprecations (hsc_dflags hsc_env) tcg_env ;
200 -- Process the export list
201 (rn_exports, exports) <- rnExports (isJust maybe_mod) export_ies ;
203 -- Rename the Haddock documentation header
204 rn_module_doc <- rnMbHsDoc maybe_doc ;
206 -- Rename the Haddock module info
207 rn_description <- rnMbHsDoc (hmi_description module_info) ;
208 let { rn_module_info = module_info { hmi_description = rn_description } } ;
210 -- Check whether the entire module is deprecated
211 -- This happens only once per module
212 let { mod_deprecs = checkModDeprec mod_deprec } ;
214 -- Add exports and deprecations to envt
215 let { final_env = tcg_env { tcg_exports = exports,
216 tcg_rn_exports = if save_rn_syntax then
219 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly (availsToNameSet exports),
220 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
222 tcg_doc = rn_module_doc,
223 tcg_hmi = rn_module_info
225 -- A module deprecation over-rides the earlier ones
228 -- Report unused names
229 reportUnusedNames export_ies final_env ;
231 -- Dump output and return
238 %************************************************************************
240 Type-checking external-core modules
242 %************************************************************************
245 tcRnExtCore :: HscEnv
247 -> IO (Messages, Maybe ModGuts)
248 -- Nothing => some error occurred
250 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
251 -- The decls are IfaceDecls; all names are original names
252 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
254 initTc hsc_env ExtCoreFile this_mod $ do {
256 let { ldecls = map noLoc decls } ;
258 -- Deal with the type declarations; first bring their stuff
259 -- into scope, then rname them, then type check them
260 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
262 setGblEnv tcg_env $ do {
264 rn_decls <- rnTyClDecls ldecls ;
267 -- Dump trace of renaming part
268 rnDump (ppr rn_decls) ;
270 -- Typecheck them all together so that
271 -- any mutually recursive types are done right
272 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
273 -- Make the new type env available to stuff slurped from interface files
275 setGblEnv tcg_env $ do {
277 -- Now the core bindings
278 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
282 bndrs = bindersOfBinds core_binds ;
283 my_exports = map (Avail . idName) bndrs ;
284 -- ToDo: export the data types also?
286 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
288 mod_guts = ModGuts { mg_module = this_mod,
290 mg_usages = [], -- ToDo: compute usage
291 mg_dir_imps = [], -- ??
292 mg_deps = noDependencies, -- ??
293 mg_exports = my_exports,
294 mg_types = final_type_env,
295 mg_insts = tcg_insts tcg_env,
296 mg_fam_insts = tcg_fam_insts tcg_env,
298 mg_binds = core_binds,
301 mg_rdr_env = emptyGlobalRdrEnv,
302 mg_fix_env = emptyFixityEnv,
303 mg_deprecs = NoDeprecs,
307 tcCoreDump mod_guts ;
312 mkFakeGroup decls -- Rather clumsy; lots of unused fields
313 = emptyRdrGroup { hs_tyclds = decls }
317 %************************************************************************
319 Type-checking the top level of a module
321 %************************************************************************
324 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
325 -- Returns the variables free in the decls
326 -- Reason: solely to report unused imports and bindings
328 = do { -- Load the hi-boot interface for this module, if any
329 -- We do this now so that the boot_names can be passed
330 -- to tcTyAndClassDecls, because the boot_names are
331 -- automatically considered to be loop breakers
333 boot_iface <- tcHiBootIface mod ;
335 -- Do all the declarations
336 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_iface decls) ;
338 -- tcSimplifyTop deals with constant or ambiguous InstIds.
339 -- How could there be ambiguous ones? They can only arise if a
340 -- top-level decl falls under the monomorphism
341 -- restriction, and no subsequent decl instantiates its
342 -- type. (Usually, ambiguous type variables are resolved
343 -- during the generalisation step.)
344 traceTc (text "Tc8") ;
345 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
346 -- Setting the global env exposes the instances to tcSimplifyTop
347 -- Setting the local env exposes the local Ids to tcSimplifyTop,
348 -- so that we get better error messages (monomorphism restriction)
350 -- Backsubstitution. This must be done last.
351 -- Even tcSimplifyTop may do some unification.
352 traceTc (text "Tc9") ;
353 let { (tcg_env, _) = tc_envs ;
354 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
355 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
357 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
360 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
361 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
364 tcg_fords = fords' } } ;
366 -- Make the new type env available to stuff slurped from interface files
367 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
369 -- Compare the hi-boot iface (if any) with the real thing
370 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
372 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
375 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
376 -- Loops around dealing with each top level inter-splice group
377 -- in turn, until it's dealt with the entire module
378 tc_rn_src_decls boot_details ds
379 = do { let { (first_group, group_tail) = findSplice ds } ;
380 -- If ds is [] we get ([], Nothing)
382 -- Type check the decls up to, but not including, the first splice
383 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_details first_group ;
385 -- Bale out if errors; for example, error recovery when checking
386 -- the RHS of 'main' can mean that 'main' is not in the envt for
387 -- the subsequent checkMain test
392 -- If there is no splice, we're nearly done
394 Nothing -> do { -- Last thing: check for `main'
395 tcg_env <- checkMain ;
396 return (tcg_env, tcl_env)
399 -- If there's a splice, we must carry on
400 Just (SpliceDecl splice_expr, rest_ds) -> do {
402 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
405 -- Rename the splice expression, and get its supporting decls
406 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
407 failIfErrsM ; -- Don't typecheck if renaming failed
408 rnDump (ppr rn_splice_expr) ;
410 -- Execute the splice
411 spliced_decls <- tcSpliceDecls rn_splice_expr ;
413 -- Glue them on the front of the remaining decls and loop
414 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
415 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
420 %************************************************************************
422 Compiling hs-boot source files, and
423 comparing the hi-boot interface with the real thing
425 %************************************************************************
428 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
429 tcRnHsBootDecls decls
430 = do { let { (first_group, group_tail) = findSplice decls }
433 Just stuff -> spliceInHsBootErr stuff
436 -- Rename the declarations
437 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
438 ; setGblEnv tcg_env $ do {
440 -- Todo: check no foreign decls, no rules, no default decls
442 -- Typecheck type/class decls
443 ; traceTc (text "Tc2")
444 ; let tycl_decls = hs_tyclds rn_group
445 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
446 ; setGblEnv tcg_env $ do {
448 -- Typecheck instance decls
449 ; traceTc (text "Tc3")
450 ; (tcg_env, inst_infos, _binds)
451 <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group)
452 ; setGblEnv tcg_env $ do {
454 -- Typecheck value declarations
455 ; traceTc (text "Tc5")
456 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
459 -- No simplification or zonking to do
460 ; traceTc (text "Tc7a")
461 ; gbl_env <- getGblEnv
463 -- Make the final type-env
464 -- Include the dfun_ids so that their type sigs get
465 -- are written into the interface file
466 ; let { type_env0 = tcg_type_env gbl_env
467 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
468 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
469 ; dfun_ids = map iDFunId inst_infos }
470 ; return (gbl_env { tcg_type_env = type_env2 })
473 spliceInHsBootErr (SpliceDecl (L loc _), _)
474 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
477 Once we've typechecked the body of the module, we want to compare what
478 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
481 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
482 -- Compare the hi-boot file for this module (if there is one)
483 -- with the type environment we've just come up with
484 -- In the common case where there is no hi-boot file, the list
485 -- of boot_names is empty.
487 -- The bindings we return give bindings for the dfuns defined in the
488 -- hs-boot file, such as $fbEqT = $fEqT
491 (TcGblEnv { tcg_insts = local_insts, tcg_fam_insts = local_fam_insts,
492 tcg_type_env = local_type_env })
493 (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts,
494 md_types = boot_type_env })
495 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts)) ;
496 ; mapM_ check_one (typeEnvElts boot_type_env)
497 ; dfun_binds <- mapM check_inst boot_insts
498 ; unless (null boot_fam_insts) $
499 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
500 "instances in boot files yet...")
501 -- FIXME: Why? The actual comparison is not hard, but what would
502 -- be the equivalent to the dfun bindings returned for class
503 -- instances? We can't easily equate tycons...
504 ; return (unionManyBags dfun_binds) }
507 | isImplicitTyThing boot_thing = return ()
508 | name `elem` dfun_names = return ()
509 | isWiredInName name = return () -- No checking for wired-in names. In particular,
510 -- 'error' is handled by a rather gross hack
511 -- (see comments in GHC.Err.hs-boot)
512 | Just real_thing <- lookupTypeEnv local_type_env name
513 = do { let boot_decl = tyThingToIfaceDecl boot_thing
514 real_decl = tyThingToIfaceDecl real_thing
515 ; checkTc (checkBootDecl boot_decl real_decl)
516 (bootMisMatch boot_thing boot_decl real_decl) }
517 -- The easiest way to check compatibility is to convert to
518 -- iface syntax, where we already have good comparison functions
520 = addErrTc (missingBootThing boot_thing)
522 name = getName boot_thing
524 dfun_names = map getName boot_insts
527 = case [dfun | inst <- local_insts,
528 let dfun = instanceDFunId inst,
529 idType dfun `tcEqType` boot_inst_ty ] of
530 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
531 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
533 boot_dfun = instanceDFunId boot_inst
534 boot_inst_ty = idType boot_dfun
535 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
538 missingBootThing thing
539 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
540 bootMisMatch thing boot_decl real_decl
541 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
542 ptext SLIT("Decl") <+> ppr real_decl,
543 ptext SLIT("Boot file:") <+> ppr boot_decl]
546 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
550 %************************************************************************
552 Type-checking the top level of a module
554 %************************************************************************
556 tcRnGroup takes a bunch of top-level source-code declarations, and
558 * gets supporting declarations from interface files
561 * and augments the TcGblEnv with the results
563 In Template Haskell it may be called repeatedly for each group of
564 declarations. It expects there to be an incoming TcGblEnv in the
565 monad; it augments it and returns the new TcGblEnv.
568 tcRnGroup :: ModDetails -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
569 -- Returns the variables free in the decls, for unused-binding reporting
570 tcRnGroup boot_details decls
571 = do { -- Rename the declarations
572 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
573 setGblEnv tcg_env $ do {
575 -- Typecheck the declarations
576 tcTopSrcDecls boot_details rn_decls
579 ------------------------------------------------
580 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
582 = do { -- Bring top level binders into scope
583 tcg_env <- importsFromLocalDecls group ;
584 setGblEnv tcg_env $ do {
586 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
588 -- Rename the source decls
589 (tcg_env, rn_decls) <- rnSrcDecls group ;
592 -- save the renamed syntax, if we want it
594 | Just grp <- tcg_rn_decls tcg_env
595 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
599 -- Dump trace of renaming part
600 rnDump (ppr rn_decls) ;
602 return (tcg_env', rn_decls)
605 ------------------------------------------------
606 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
607 tcTopSrcDecls boot_details
608 (HsGroup { hs_tyclds = tycl_decls,
609 hs_instds = inst_decls,
610 hs_derivds = deriv_decls,
611 hs_fords = foreign_decls,
612 hs_defds = default_decls,
613 hs_ruleds = rule_decls,
614 hs_valds = val_binds })
615 = do { -- Type-check the type and class decls, and all imported decls
616 -- The latter come in via tycl_decls
617 traceTc (text "Tc2") ;
619 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
620 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
621 -- an error we'd better stop now, to avoid a cascade
623 -- Make these type and class decls available to stuff slurped from interface files
624 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
627 setGblEnv tcg_env $ do {
628 -- Source-language instances, including derivings,
629 -- and import the supporting declarations
630 traceTc (text "Tc3") ;
631 (tcg_env, inst_infos, deriv_binds)
632 <- tcInstDecls1 tycl_decls inst_decls deriv_decls;
633 setGblEnv tcg_env $ do {
635 -- Foreign import declarations next. No zonking necessary
636 -- here; we can tuck them straight into the global environment.
637 traceTc (text "Tc4") ;
638 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
639 tcExtendGlobalValEnv fi_ids $ do {
641 -- Default declarations
642 traceTc (text "Tc4a") ;
643 default_tys <- tcDefaults default_decls ;
644 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
646 -- Value declarations next
647 -- We also typecheck any extra binds that came out
648 -- of the "deriving" process (deriv_binds)
649 traceTc (text "Tc5") ;
650 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
651 setLclTypeEnv tcl_env $ do {
653 -- Second pass over class and instance declarations,
654 traceTc (text "Tc6") ;
655 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
656 showLIE (text "after instDecls2") ;
659 -- They need to be zonked, so we return them
660 traceTc (text "Tc7") ;
661 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
664 rules <- tcRules rule_decls ;
667 traceTc (text "Tc7a") ;
668 tcg_env <- getGblEnv ;
669 let { all_binds = tc_val_binds `unionBags`
670 inst_binds `unionBags`
673 -- Extend the GblEnv with the (as yet un-zonked)
674 -- bindings, rules, foreign decls
675 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
676 tcg_rules = tcg_rules tcg_env ++ rules,
677 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
678 return (tcg_env', tcl_env)
683 %************************************************************************
687 %************************************************************************
690 checkMain :: TcM TcGblEnv
691 -- If we are in module Main, check that 'main' is defined.
693 = do { ghc_mode <- getGhcMode ;
694 tcg_env <- getGblEnv ;
696 let { main_mod = mainModIs dflags ;
697 main_fn = case mainFunIs dflags of {
698 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
699 Nothing -> main_RDR_Unqual } } ;
701 check_main ghc_mode tcg_env main_mod main_fn
705 check_main ghc_mode tcg_env main_mod main_fn
707 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
711 = addErrCtxt mainCtxt $
712 do { mb_main <- lookupSrcOcc_maybe main_fn
713 -- Check that 'main' is in scope
714 -- It might be imported from another module!
716 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
720 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
721 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
722 -- :Main.main :: IO () = runMainIO main
724 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
727 -- The function that the RTS invokes is always :Main.main,
728 -- which we call root_main_id.
729 -- (Because GHC allows the user to have a module not called
730 -- Main as the main module, we can't rely on the main function
731 -- being called "Main.main". That's why root_main_id has a fixed
733 -- We also make root_main_id an implicit Id, by making main_name
734 -- its parent (hence (Just main_name)). That has the effect
735 -- of preventing its type and unfolding from getting out into
736 -- the interface file. Otherwise we can end up with two defns
737 -- for 'main' in the interface file!
739 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
740 (mkVarOccFS FSLIT("main"))
741 (getSrcLoc main_name)
742 ; root_main_id = Id.mkExportedLocalId root_main_name ty
743 ; main_bind = noLoc (VarBind root_main_id main_expr) }
745 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
747 tcg_dus = tcg_dus tcg_env
748 `plusDU` usesOnly (unitFV main_name)
749 -- Record the use of 'main', so that we don't
750 -- complain about it being defined but not used
754 mod = tcg_mod tcg_env
756 complain_no_main | ghc_mode == Interactive = return ()
757 | otherwise = failWithTc noMainMsg
758 -- In interactive mode, don't worry about the absence of 'main'
759 -- In other modes, fail altogether, so that we don't go on
760 -- and complain a second time when processing the export list.
762 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
763 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
764 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
767 %*********************************************************
771 %*********************************************************
775 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
776 setInteractiveContext hsc_env icxt thing_inside
778 -- Initialise the tcg_inst_env with instances
779 -- from all home modules. This mimics the more selective
780 -- call to hptInstances in tcRnModule
781 dfuns = hptInstances hsc_env (\mod -> True)
783 updGblEnv (\env -> env {
784 tcg_rdr_env = ic_rn_gbl_env icxt,
785 tcg_type_env = ic_type_env icxt,
786 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
788 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
790 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
797 -> InteractiveContext
799 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
800 -- The returned [Name] is the same as the input except for
801 -- ExprStmt, in which case the returned [Name] is [itName]
803 -- The returned TypecheckedHsExpr is of type IO [ () ],
804 -- a list of the bound values, coerced to ().
806 tcRnStmt hsc_env ictxt rdr_stmt
807 = initTcPrintErrors hsc_env iNTERACTIVE $
808 setInteractiveContext hsc_env ictxt $ do {
810 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
811 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
812 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
815 -- The real work is done here
816 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
817 zonked_expr <- zonkTopLExpr tc_expr ;
818 zonked_ids <- zonkTopBndrs bound_ids ;
820 -- None of the Ids should be of unboxed type, because we
821 -- cast them all to HValues in the end!
822 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
824 traceTc (text "tcs 1") ;
825 let { -- (a) Make all the bound ids "global" ids, now that
826 -- they're notionally top-level bindings. This is
827 -- important: otherwise when we come to compile an expression
828 -- using these ids later, the byte code generator will consider
829 -- the occurrences to be free rather than global.
831 -- (b) Tidy their types; this is important, because :info may
832 -- ask to look at them, and :info expects the things it looks
833 -- up to have tidy types
834 global_ids = map globaliseAndTidy zonked_ids ;
836 -- Update the interactive context
837 rn_env = ic_rn_local_env ictxt ;
838 type_env = ic_type_env ictxt ;
840 bound_names = map idName global_ids ;
841 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
843 {- ---------------------------------------------
844 At one stage I removed any shadowed bindings from the type_env;
845 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
846 However, with Template Haskell they aren't necessarily inaccessible. Consider this
848 Prelude> let f n = n * 2 :: Int
849 Prelude> fName <- runQ [| f |]
850 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
852 Prelude> let f n = n * 3 :: Int
853 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
854 In the last line we use 'fName', which resolves to the *first* 'f'
855 in scope. If we delete it from the type env, GHCi crashes because
856 it doesn't expect that.
858 Hence this code is commented out
860 shadowed = [ n | name <- bound_names,
861 let rdr_name = mkRdrUnqual (nameOccName name),
862 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
863 filtered_type_env = delListFromNameEnv type_env shadowed ;
864 -------------------------------------------------- -}
866 new_type_env = extendTypeEnvWithIds type_env global_ids ;
867 new_ic = ictxt { ic_rn_local_env = new_rn_env,
868 ic_type_env = new_type_env }
871 dumpOptTcRn Opt_D_dump_tc
872 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
873 text "Typechecked expr" <+> ppr zonked_expr]) ;
875 returnM (new_ic, bound_names, zonked_expr)
878 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
879 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
881 globaliseAndTidy :: Id -> Id
883 -- Give the Id a Global Name, and tidy its type
884 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
886 tidy_type = tidyTopType (idType id)
889 Here is the grand plan, implemented in tcUserStmt
891 What you type The IO [HValue] that hscStmt returns
892 ------------- ------------------------------------
893 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
896 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
899 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
900 [NB: result not printed] bindings: [it]
902 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
903 result showable) bindings: [it]
905 expr (of non-IO type,
906 result not showable) ==> error
910 ---------------------------
911 type PlanResult = ([Id], LHsExpr Id)
912 type Plan = TcM PlanResult
914 runPlans :: [Plan] -> TcM PlanResult
915 -- Try the plans in order. If one fails (by raising an exn), try the next.
916 -- If one succeeds, take it.
917 runPlans [] = panic "runPlans"
919 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
922 mkPlan :: LStmt Name -> TcM PlanResult
923 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
924 = do { uniq <- newUnique -- is treated very specially
925 ; let fresh_it = itName uniq
926 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
927 matches = [mkMatch [] expr emptyLocalBinds]
928 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
929 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
930 (HsVar bindIOName) noSyntaxExpr
931 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
932 (HsVar thenIOName) placeHolderType
935 -- [it <- e; print it] but not if it::()
937 -- [let it = e; print it]
938 ; runPlans [ -- Plan A
939 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
940 ; it_ty <- zonkTcType (idType it_id)
941 ; ifM (isUnitTy it_ty) failM
944 -- Plan B; a naked bind statment
945 tcGhciStmts [bind_stmt],
947 -- Plan C; check that the let-binding is typeable all by itself.
948 -- If not, fail; if so, try to print it.
949 -- The two-step process avoids getting two errors: one from
950 -- the expression itself, and one from the 'print it' part
951 -- This two-step story is very clunky, alas
952 do { checkNoErrs (tcGhciStmts [let_stmt])
953 --- checkNoErrs defeats the error recovery of let-bindings
954 ; tcGhciStmts [let_stmt, print_it] }
957 mkPlan stmt@(L loc (BindStmt {}))
958 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
959 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
960 (HsVar thenIOName) placeHolderType
962 ; print_bind_result <- doptM Opt_PrintBindResult
963 ; let print_plan = do
964 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
965 ; v_ty <- zonkTcType (idType v_id)
966 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
970 -- [stmt; print v] but not if v::()
972 ; runPlans ((if print_bind_result then [print_plan] else []) ++
973 [tcGhciStmts [stmt]])
979 ---------------------------
980 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
982 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
983 ret_id <- tcLookupId returnIOName ; -- return @ IO
985 io_ty = mkTyConApp ioTyCon [] ;
986 ret_ty = mkListTy unitTy ;
987 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
988 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
989 (emptyRefinement, io_ret_ty) ;
991 names = map unLoc (collectLStmtsBinders stmts) ;
993 -- mk_return builds the expression
994 -- returnIO @ [()] [coerce () x, .., coerce () z]
996 -- Despite the inconvenience of building the type applications etc,
997 -- this *has* to be done in type-annotated post-typecheck form
998 -- because we are going to return a list of *polymorphic* values
999 -- coerced to type (). If we built a *source* stmt
1000 -- return [coerce x, ..., coerce z]
1001 -- then the type checker would instantiate x..z, and we wouldn't
1002 -- get their *polymorphic* values. (And we'd get ambiguity errs
1003 -- if they were overloaded, since they aren't applied to anything.)
1004 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
1005 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1006 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1010 -- OK, we're ready to typecheck the stmts
1011 traceTc (text "tcs 2") ;
1012 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1013 mappM tcLookupId names ;
1014 -- Look up the names right in the middle,
1015 -- where they will all be in scope
1017 -- Simplify the context
1018 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1019 -- checkNoErrs ensures that the plan fails if context redn fails
1021 return (ids, mkHsDictLet const_binds $
1022 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1027 tcRnExpr just finds the type of an expression
1031 -> InteractiveContext
1034 tcRnExpr hsc_env ictxt rdr_expr
1035 = initTcPrintErrors hsc_env iNTERACTIVE $
1036 setInteractiveContext hsc_env ictxt $ do {
1038 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1041 -- Now typecheck the expression;
1042 -- it might have a rank-2 type (e.g. :t runST)
1043 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1044 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1045 tcSimplifyInteractive lie_top ;
1046 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
1048 let { all_expr_ty = mkForAllTys qtvs' $
1049 mkFunTys (map idType dict_ids) $
1051 zonkTcType all_expr_ty
1054 smpl_doc = ptext SLIT("main expression")
1057 tcRnType just finds the kind of a type
1061 -> InteractiveContext
1064 tcRnType hsc_env ictxt rdr_type
1065 = initTcPrintErrors hsc_env iNTERACTIVE $
1066 setInteractiveContext hsc_env ictxt $ do {
1068 rn_type <- rnLHsType doc rdr_type ;
1071 -- Now kind-check the type
1072 (ty', kind) <- kcHsType rn_type ;
1076 doc = ptext SLIT("In GHCi input")
1082 %************************************************************************
1084 More GHCi stuff, to do with browsing and getting info
1086 %************************************************************************
1090 -- ASSUMES that the module is either in the HomePackageTable or is
1091 -- a package module with an interface on disk. If neither of these is
1092 -- true, then the result will be an error indicating the interface
1093 -- could not be found.
1094 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1095 getModuleExports hsc_env mod
1096 = initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod)
1098 tcGetModuleExports :: Module -> TcM [AvailInfo]
1099 tcGetModuleExports mod = do
1100 let doc = ptext SLIT("context for compiling statements")
1101 iface <- initIfaceTcRn $ loadSysInterface doc mod
1102 loadOrphanModules (dep_orphs (mi_deps iface)) False
1103 -- Load any orphan-module interfaces,
1104 -- so their instances are visible
1105 loadOrphanModules (dep_finsts (mi_deps iface)) True
1106 -- Load any family instance-module interfaces,
1107 -- so all family instances are visible
1108 ifaceExportNames (mi_exports iface)
1110 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1111 tcRnLookupRdrName hsc_env rdr_name
1112 = initTcPrintErrors hsc_env iNTERACTIVE $
1113 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1114 lookup_rdr_name rdr_name
1116 lookup_rdr_name rdr_name = do {
1117 -- If the identifier is a constructor (begins with an
1118 -- upper-case letter), then we need to consider both
1119 -- constructor and type class identifiers.
1120 let { rdr_names = dataTcOccs rdr_name } ;
1122 -- results :: [Either Messages Name]
1123 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1125 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1126 -- The successful lookups will be (Just name)
1127 let { (warns_s, good_names) = unzip [ (msgs, name)
1128 | (msgs, Just name) <- results] ;
1129 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1131 -- Fail if nothing good happened, else add warnings
1132 if null good_names then
1133 -- No lookup succeeded, so
1134 -- pick the first error message and report it
1135 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1136 -- while the other is "X is not in scope",
1137 -- we definitely want the former; but we might pick the latter
1138 do { addMessages (head errs_s) ; failM }
1139 else -- Add deprecation warnings
1140 mapM_ addMessages warns_s ;
1146 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1147 tcRnLookupName hsc_env name
1148 = initTcPrintErrors hsc_env iNTERACTIVE $
1149 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1153 tcRnGetInfo :: HscEnv
1155 -> IO (Maybe (TyThing, Fixity, [Instance]))
1157 -- Used to implemnent :info in GHCi
1159 -- Look up a RdrName and return all the TyThings it might be
1160 -- A capitalised RdrName is given to us in the DataName namespace,
1161 -- but we want to treat it as *both* a data constructor
1162 -- *and* as a type or class constructor;
1163 -- hence the call to dataTcOccs, and we return up to two results
1164 tcRnGetInfo hsc_env name
1165 = initTcPrintErrors hsc_env iNTERACTIVE $
1166 let ictxt = hsc_IC hsc_env in
1167 setInteractiveContext hsc_env ictxt $ do
1169 -- Load the interface for all unqualified types and classes
1170 -- That way we will find all the instance declarations
1171 -- (Packages have not orphan modules, and we assume that
1172 -- in the home package all relevant modules are loaded.)
1173 loadUnqualIfaces ictxt
1175 thing <- tcLookupGlobal name
1176 fixity <- lookupFixityRn name
1177 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1178 return (thing, fixity, ispecs)
1181 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1182 -- Filter the instances by the ones whose tycons (or clases resp)
1183 -- are in scope unqualified. Otherwise we list a whole lot too many!
1184 lookupInsts print_unqual (AClass cls)
1185 = do { inst_envs <- tcGetInstEnvs
1187 | ispec <- classInstances inst_envs cls
1188 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1190 lookupInsts print_unqual (ATyCon tc)
1191 = do { eps <- getEps -- Load all instances for all classes that are
1192 -- in the type environment (which are all the ones
1193 -- we've seen in any interface file so far)
1194 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1196 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1197 , let dfun = instanceDFunId ispec
1199 , plausibleDFun print_unqual dfun ] }
1201 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1202 tc_name = tyConName tc
1204 lookupInsts print_unqual other = return []
1206 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1207 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1209 ok name | isBuiltInSyntax name = True
1210 | isExternalName name =
1211 isNothing $ fst print_unqual (nameModule name)
1215 loadUnqualIfaces :: InteractiveContext -> TcM ()
1216 -- Load the home module for everything that is in scope unqualified
1217 -- This is so that we can accurately report the instances for
1219 loadUnqualIfaces ictxt
1221 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1223 unqual_mods = [ nameModule name
1224 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1225 let name = gre_name gre,
1226 not (isInternalName name),
1227 isTcOcc (nameOccName name), -- Types and classes only
1228 unQualOK gre ] -- In scope unqualified
1229 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1233 %************************************************************************
1237 %************************************************************************
1240 rnDump :: SDoc -> TcRn ()
1241 -- Dump, with a banner, if -ddump-rn
1242 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1244 tcDump :: TcGblEnv -> TcRn ()
1246 = do { dflags <- getDOpts ;
1248 -- Dump short output if -ddump-types or -ddump-tc
1249 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1250 (dumpTcRn short_dump) ;
1252 -- Dump bindings if -ddump-tc
1253 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1256 short_dump = pprTcGblEnv env
1257 full_dump = pprLHsBinds (tcg_binds env)
1258 -- NB: foreign x-d's have undefined's in their types;
1259 -- hence can't show the tc_fords
1262 = do { dflags <- getDOpts ;
1263 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1264 (dumpTcRn (pprModGuts mod_guts)) ;
1266 -- Dump bindings if -ddump-tc
1267 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1269 full_dump = pprCoreBindings (mg_binds mod_guts)
1271 -- It's unpleasant having both pprModGuts and pprModDetails here
1272 pprTcGblEnv :: TcGblEnv -> SDoc
1273 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1275 tcg_fam_insts = fam_insts,
1277 tcg_imports = imports })
1278 = vcat [ ppr_types insts type_env
1280 , ppr_fam_insts fam_insts
1281 , vcat (map ppr rules)
1282 , ppr_gen_tycons (typeEnvTyCons type_env)
1283 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1284 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1286 pprModGuts :: ModGuts -> SDoc
1287 pprModGuts (ModGuts { mg_types = type_env,
1289 = vcat [ ppr_types [] type_env,
1292 ppr_types :: [Instance] -> TypeEnv -> SDoc
1293 ppr_types insts type_env
1294 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1296 dfun_ids = map instanceDFunId insts
1297 ids = [id | id <- typeEnvIds type_env, want_sig id]
1298 want_sig id | opt_PprStyle_Debug = True
1299 | otherwise = isLocalId id &&
1300 isExternalName (idName id) &&
1301 not (id `elem` dfun_ids)
1302 -- isLocalId ignores data constructors, records selectors etc.
1303 -- The isExternalName ignores local dictionary and method bindings
1304 -- that the type checker has invented. Top-level user-defined things
1305 -- have External names.
1307 ppr_insts :: [Instance] -> SDoc
1308 ppr_insts [] = empty
1309 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1311 ppr_fam_insts :: [FamInst] -> SDoc
1312 ppr_fam_insts [] = empty
1313 ppr_fam_insts fam_insts =
1314 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1316 ppr_sigs :: [Var] -> SDoc
1318 -- Print type signatures; sort by OccName
1319 = vcat (map ppr_sig (sortLe le_sig ids))
1321 le_sig id1 id2 = getOccName id1 <= getOccName id2
1322 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1324 ppr_rules :: [CoreRule] -> SDoc
1325 ppr_rules [] = empty
1326 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1327 nest 4 (pprRules rs),
1330 ppr_gen_tycons [] = empty
1331 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1332 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]