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 -- See Note [Root-main Id]
730 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
731 (mkVarOccFS FSLIT("main"))
732 (getSrcLoc main_name)
733 ; root_main_id = Id.mkExportedLocalId root_main_name ty
734 ; main_bind = noLoc (VarBind root_main_id main_expr) }
736 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
738 tcg_dus = tcg_dus tcg_env
739 `plusDU` usesOnly (unitFV main_name)
740 -- Record the use of 'main', so that we don't
741 -- complain about it being defined but not used
745 mod = tcg_mod tcg_env
747 complain_no_main | ghc_mode == Interactive = return ()
748 | otherwise = failWithTc noMainMsg
749 -- In interactive mode, don't worry about the absence of 'main'
750 -- In other modes, fail altogether, so that we don't go on
751 -- and complain a second time when processing the export list.
753 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
754 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
755 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
760 The function that the RTS invokes is always :Main.main, which we call
761 root_main_id. (Because GHC allows the user to have a module not
762 called Main as the main module, we can't rely on the main function
763 being called "Main.main". That's why root_main_id has a fixed module
766 This is unusual: it's a LocalId whose Name has a Module from another
767 module. Tiresomely, we must filter it out again in MkIface, les we
768 get two defns for 'main' in the interface file!
771 %*********************************************************
775 %*********************************************************
779 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
780 setInteractiveContext hsc_env icxt thing_inside
782 -- Initialise the tcg_inst_env with instances
783 -- from all home modules. This mimics the more selective
784 -- call to hptInstances in tcRnModule
785 dfuns = hptInstances hsc_env (\mod -> True)
787 updGblEnv (\env -> env {
788 tcg_rdr_env = ic_rn_gbl_env icxt,
789 tcg_type_env = ic_type_env icxt,
790 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
792 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
794 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
801 -> InteractiveContext
803 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
804 -- The returned [Name] is the same as the input except for
805 -- ExprStmt, in which case the returned [Name] is [itName]
807 -- The returned TypecheckedHsExpr is of type IO [ () ],
808 -- a list of the bound values, coerced to ().
810 tcRnStmt hsc_env ictxt rdr_stmt
811 = initTcPrintErrors hsc_env iNTERACTIVE $
812 setInteractiveContext hsc_env ictxt $ do {
814 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
815 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
816 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
819 -- The real work is done here
820 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
821 zonked_expr <- zonkTopLExpr tc_expr ;
822 zonked_ids <- zonkTopBndrs bound_ids ;
824 -- None of the Ids should be of unboxed type, because we
825 -- cast them all to HValues in the end!
826 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
828 traceTc (text "tcs 1") ;
829 let { -- (a) Make all the bound ids "global" ids, now that
830 -- they're notionally top-level bindings. This is
831 -- important: otherwise when we come to compile an expression
832 -- using these ids later, the byte code generator will consider
833 -- the occurrences to be free rather than global.
835 -- (b) Tidy their types; this is important, because :info may
836 -- ask to look at them, and :info expects the things it looks
837 -- up to have tidy types
838 global_ids = map globaliseAndTidy zonked_ids ;
840 -- Update the interactive context
841 rn_env = ic_rn_local_env ictxt ;
842 type_env = ic_type_env ictxt ;
844 bound_names = map idName global_ids ;
845 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
847 {- ---------------------------------------------
848 At one stage I removed any shadowed bindings from the type_env;
849 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
850 However, with Template Haskell they aren't necessarily inaccessible. Consider this
852 Prelude> let f n = n * 2 :: Int
853 Prelude> fName <- runQ [| f |]
854 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
856 Prelude> let f n = n * 3 :: Int
857 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
858 In the last line we use 'fName', which resolves to the *first* 'f'
859 in scope. If we delete it from the type env, GHCi crashes because
860 it doesn't expect that.
862 Hence this code is commented out
864 shadowed = [ n | name <- bound_names,
865 let rdr_name = mkRdrUnqual (nameOccName name),
866 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
867 filtered_type_env = delListFromNameEnv type_env shadowed ;
868 -------------------------------------------------- -}
870 new_type_env = extendTypeEnvWithIds type_env global_ids ;
871 new_ic = ictxt { ic_rn_local_env = new_rn_env,
872 ic_type_env = new_type_env }
875 dumpOptTcRn Opt_D_dump_tc
876 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
877 text "Typechecked expr" <+> ppr zonked_expr]) ;
879 returnM (new_ic, bound_names, zonked_expr)
882 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
883 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
885 globaliseAndTidy :: Id -> Id
887 -- Give the Id a Global Name, and tidy its type
888 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
890 tidy_type = tidyTopType (idType id)
893 Here is the grand plan, implemented in tcUserStmt
895 What you type The IO [HValue] that hscStmt returns
896 ------------- ------------------------------------
897 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
900 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
903 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
904 [NB: result not printed] bindings: [it]
906 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
907 result showable) bindings: [it]
909 expr (of non-IO type,
910 result not showable) ==> error
914 ---------------------------
915 type PlanResult = ([Id], LHsExpr Id)
916 type Plan = TcM PlanResult
918 runPlans :: [Plan] -> TcM PlanResult
919 -- Try the plans in order. If one fails (by raising an exn), try the next.
920 -- If one succeeds, take it.
921 runPlans [] = panic "runPlans"
923 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
926 mkPlan :: LStmt Name -> TcM PlanResult
927 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
928 = do { uniq <- newUnique -- is treated very specially
929 ; let fresh_it = itName uniq
930 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
931 matches = [mkMatch [] expr emptyLocalBinds]
932 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
933 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
934 (HsVar bindIOName) noSyntaxExpr
935 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
936 (HsVar thenIOName) placeHolderType
939 -- [it <- e; print it] but not if it::()
941 -- [let it = e; print it]
942 ; runPlans [ -- Plan A
943 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
944 ; it_ty <- zonkTcType (idType it_id)
945 ; ifM (isUnitTy it_ty) failM
948 -- Plan B; a naked bind statment
949 tcGhciStmts [bind_stmt],
951 -- Plan C; check that the let-binding is typeable all by itself.
952 -- If not, fail; if so, try to print it.
953 -- The two-step process avoids getting two errors: one from
954 -- the expression itself, and one from the 'print it' part
955 -- This two-step story is very clunky, alas
956 do { checkNoErrs (tcGhciStmts [let_stmt])
957 --- checkNoErrs defeats the error recovery of let-bindings
958 ; tcGhciStmts [let_stmt, print_it] }
961 mkPlan stmt@(L loc (BindStmt {}))
962 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
963 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
964 (HsVar thenIOName) placeHolderType
966 ; print_bind_result <- doptM Opt_PrintBindResult
967 ; let print_plan = do
968 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
969 ; v_ty <- zonkTcType (idType v_id)
970 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
974 -- [stmt; print v] but not if v::()
976 ; runPlans ((if print_bind_result then [print_plan] else []) ++
977 [tcGhciStmts [stmt]])
983 ---------------------------
984 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
986 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
987 ret_id <- tcLookupId returnIOName ; -- return @ IO
989 io_ty = mkTyConApp ioTyCon [] ;
990 ret_ty = mkListTy unitTy ;
991 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
992 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
993 (emptyRefinement, io_ret_ty) ;
995 names = map unLoc (collectLStmtsBinders stmts) ;
997 -- mk_return builds the expression
998 -- returnIO @ [()] [coerce () x, .., coerce () z]
1000 -- Despite the inconvenience of building the type applications etc,
1001 -- this *has* to be done in type-annotated post-typecheck form
1002 -- because we are going to return a list of *polymorphic* values
1003 -- coerced to type (). If we built a *source* stmt
1004 -- return [coerce x, ..., coerce z]
1005 -- then the type checker would instantiate x..z, and we wouldn't
1006 -- get their *polymorphic* values. (And we'd get ambiguity errs
1007 -- if they were overloaded, since they aren't applied to anything.)
1008 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
1009 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1010 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1014 -- OK, we're ready to typecheck the stmts
1015 traceTc (text "tcs 2") ;
1016 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1017 mappM tcLookupId names ;
1018 -- Look up the names right in the middle,
1019 -- where they will all be in scope
1021 -- Simplify the context
1022 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1023 -- checkNoErrs ensures that the plan fails if context redn fails
1025 return (ids, mkHsDictLet const_binds $
1026 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1031 tcRnExpr just finds the type of an expression
1035 -> InteractiveContext
1038 tcRnExpr hsc_env ictxt rdr_expr
1039 = initTcPrintErrors hsc_env iNTERACTIVE $
1040 setInteractiveContext hsc_env ictxt $ do {
1042 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1045 -- Now typecheck the expression;
1046 -- it might have a rank-2 type (e.g. :t runST)
1047 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1048 ((qtvs, dict_insts, _), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1049 tcSimplifyInteractive lie_top ;
1051 let { all_expr_ty = mkForAllTys qtvs $
1052 mkFunTys (map (idType . instToId) dict_insts) $
1054 zonkTcType all_expr_ty
1057 smpl_doc = ptext SLIT("main expression")
1060 tcRnType just finds the kind of a type
1064 -> InteractiveContext
1067 tcRnType hsc_env ictxt rdr_type
1068 = initTcPrintErrors hsc_env iNTERACTIVE $
1069 setInteractiveContext hsc_env ictxt $ do {
1071 rn_type <- rnLHsType doc rdr_type ;
1074 -- Now kind-check the type
1075 (ty', kind) <- kcHsType rn_type ;
1079 doc = ptext SLIT("In GHCi input")
1085 %************************************************************************
1087 More GHCi stuff, to do with browsing and getting info
1089 %************************************************************************
1093 -- ASSUMES that the module is either in the HomePackageTable or is
1094 -- a package module with an interface on disk. If neither of these is
1095 -- true, then the result will be an error indicating the interface
1096 -- could not be found.
1097 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1098 getModuleExports hsc_env mod
1101 checkMods = ic_toplev_scope ic ++ ic_exports ic
1103 initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod checkMods)
1105 -- Get the export avail info and also load all orphan and family-instance
1106 -- modules. Finally, check that the family instances of all modules in the
1107 -- interactive context are consistent (these modules are in the second
1109 tcGetModuleExports :: Module -> [Module] -> TcM [AvailInfo]
1110 tcGetModuleExports mod directlyImpMods
1111 = do { let doc = ptext SLIT("context for compiling statements")
1112 ; iface <- initIfaceTcRn $ loadSysInterface doc mod
1114 -- Load any orphan-module and family instance-module
1115 -- interfaces, so their instances are visible.
1116 ; loadOrphanModules (dep_orphs (mi_deps iface)) False
1117 ; loadOrphanModules (dep_finsts (mi_deps iface)) True
1119 -- Check that the family instances of all directly loaded
1120 -- modules are consistent.
1121 ; checkFamInstConsistency (dep_finsts (mi_deps iface)) directlyImpMods
1123 ; ifaceExportNames (mi_exports iface)
1126 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1127 tcRnLookupRdrName hsc_env rdr_name
1128 = initTcPrintErrors hsc_env iNTERACTIVE $
1129 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1130 lookup_rdr_name rdr_name
1132 lookup_rdr_name rdr_name = do {
1133 -- If the identifier is a constructor (begins with an
1134 -- upper-case letter), then we need to consider both
1135 -- constructor and type class identifiers.
1136 let { rdr_names = dataTcOccs rdr_name } ;
1138 -- results :: [Either Messages Name]
1139 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1141 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1142 -- The successful lookups will be (Just name)
1143 let { (warns_s, good_names) = unzip [ (msgs, name)
1144 | (msgs, Just name) <- results] ;
1145 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1147 -- Fail if nothing good happened, else add warnings
1148 if null good_names then
1149 -- No lookup succeeded, so
1150 -- pick the first error message and report it
1151 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1152 -- while the other is "X is not in scope",
1153 -- we definitely want the former; but we might pick the latter
1154 do { addMessages (head errs_s) ; failM }
1155 else -- Add deprecation warnings
1156 mapM_ addMessages warns_s ;
1161 tcRnRecoverDataCon :: HscEnv -> a -> IO (Maybe DataCon)
1162 tcRnRecoverDataCon hsc_env a
1163 = initTcPrintErrors hsc_env iNTERACTIVE $
1164 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1165 do name <- recoverDataCon a
1166 tcLookupDataCon name
1168 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1169 tcRnLookupName hsc_env name
1170 = initTcPrintErrors hsc_env iNTERACTIVE $
1171 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1175 tcRnGetInfo :: HscEnv
1177 -> IO (Maybe (TyThing, Fixity, [Instance]))
1179 -- Used to implemnent :info in GHCi
1181 -- Look up a RdrName and return all the TyThings it might be
1182 -- A capitalised RdrName is given to us in the DataName namespace,
1183 -- but we want to treat it as *both* a data constructor
1184 -- *and* as a type or class constructor;
1185 -- hence the call to dataTcOccs, and we return up to two results
1186 tcRnGetInfo hsc_env name
1187 = initTcPrintErrors hsc_env iNTERACTIVE $
1188 let ictxt = hsc_IC hsc_env in
1189 setInteractiveContext hsc_env ictxt $ do
1191 -- Load the interface for all unqualified types and classes
1192 -- That way we will find all the instance declarations
1193 -- (Packages have not orphan modules, and we assume that
1194 -- in the home package all relevant modules are loaded.)
1195 loadUnqualIfaces ictxt
1197 thing <- tcLookupGlobal name
1198 fixity <- lookupFixityRn name
1199 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1200 return (thing, fixity, ispecs)
1202 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1203 -- Filter the instances by the ones whose tycons (or clases resp)
1204 -- are in scope unqualified. Otherwise we list a whole lot too many!
1205 lookupInsts print_unqual (AClass cls)
1206 = do { inst_envs <- tcGetInstEnvs
1208 | ispec <- classInstances inst_envs cls
1209 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1211 lookupInsts print_unqual (ATyCon tc)
1212 = do { eps <- getEps -- Load all instances for all classes that are
1213 -- in the type environment (which are all the ones
1214 -- we've seen in any interface file so far)
1215 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1217 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1218 , let dfun = instanceDFunId ispec
1220 , plausibleDFun print_unqual dfun ] }
1222 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1223 tc_name = tyConName tc
1225 lookupInsts print_unqual other = return []
1227 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1228 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1230 ok name | isBuiltInSyntax name = True
1231 | isExternalName name =
1232 isNothing $ fst print_unqual (nameModule name)
1236 loadUnqualIfaces :: InteractiveContext -> TcM ()
1237 -- Load the home module for everything that is in scope unqualified
1238 -- This is so that we can accurately report the instances for
1240 loadUnqualIfaces ictxt
1242 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1244 unqual_mods = [ nameModule name
1245 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1246 let name = gre_name gre,
1247 not (isInternalName name),
1248 isTcOcc (nameOccName name), -- Types and classes only
1249 unQualOK gre ] -- In scope unqualified
1250 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1254 %************************************************************************
1258 %************************************************************************
1261 rnDump :: SDoc -> TcRn ()
1262 -- Dump, with a banner, if -ddump-rn
1263 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1265 tcDump :: TcGblEnv -> TcRn ()
1267 = do { dflags <- getDOpts ;
1269 -- Dump short output if -ddump-types or -ddump-tc
1270 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1271 (dumpTcRn short_dump) ;
1273 -- Dump bindings if -ddump-tc
1274 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1277 short_dump = pprTcGblEnv env
1278 full_dump = pprLHsBinds (tcg_binds env)
1279 -- NB: foreign x-d's have undefined's in their types;
1280 -- hence can't show the tc_fords
1283 = do { dflags <- getDOpts ;
1284 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1285 (dumpTcRn (pprModGuts mod_guts)) ;
1287 -- Dump bindings if -ddump-tc
1288 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1290 full_dump = pprCoreBindings (mg_binds mod_guts)
1292 -- It's unpleasant having both pprModGuts and pprModDetails here
1293 pprTcGblEnv :: TcGblEnv -> SDoc
1294 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1296 tcg_fam_insts = fam_insts,
1298 tcg_imports = imports })
1299 = vcat [ ppr_types insts type_env
1300 , ppr_tycons fam_insts type_env
1302 , ppr_fam_insts fam_insts
1303 , vcat (map ppr rules)
1304 , ppr_gen_tycons (typeEnvTyCons type_env)
1305 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1306 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1308 pprModGuts :: ModGuts -> SDoc
1309 pprModGuts (ModGuts { mg_types = type_env,
1311 = vcat [ ppr_types [] type_env,
1314 ppr_types :: [Instance] -> TypeEnv -> SDoc
1315 ppr_types insts type_env
1316 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1318 dfun_ids = map instanceDFunId insts
1319 ids = [id | id <- typeEnvIds type_env, want_sig id]
1320 want_sig id | opt_PprStyle_Debug = True
1321 | otherwise = isLocalId id &&
1322 isExternalName (idName id) &&
1323 not (id `elem` dfun_ids)
1324 -- isLocalId ignores data constructors, records selectors etc.
1325 -- The isExternalName ignores local dictionary and method bindings
1326 -- that the type checker has invented. Top-level user-defined things
1327 -- have External names.
1329 ppr_tycons :: [FamInst] -> TypeEnv -> SDoc
1330 ppr_tycons fam_insts type_env
1331 = text "TYPE CONSTRUCTORS" $$ nest 4 (ppr_tydecls tycons)
1333 fi_tycons = map famInstTyCon fam_insts
1334 tycons = [tycon | tycon <- typeEnvTyCons type_env, want_tycon tycon]
1335 want_tycon tycon | opt_PprStyle_Debug = True
1336 | otherwise = not (isImplicitTyCon tycon) &&
1337 isExternalName (tyConName tycon) &&
1338 not (tycon `elem` fi_tycons)
1340 ppr_insts :: [Instance] -> SDoc
1341 ppr_insts [] = empty
1342 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1344 ppr_fam_insts :: [FamInst] -> SDoc
1345 ppr_fam_insts [] = empty
1346 ppr_fam_insts fam_insts =
1347 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1349 ppr_sigs :: [Var] -> SDoc
1351 -- Print type signatures; sort by OccName
1352 = vcat (map ppr_sig (sortLe le_sig ids))
1354 le_sig id1 id2 = getOccName id1 <= getOccName id2
1355 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1357 ppr_tydecls :: [TyCon] -> SDoc
1359 -- Print type constructor info; sort by OccName
1360 = vcat (map ppr_tycon (sortLe le_sig tycons))
1362 le_sig tycon1 tycon2 = getOccName tycon1 <= getOccName tycon2
1364 | isCoercionTyCon tycon = ptext SLIT("coercion") <+> ppr tycon
1365 | otherwise = ppr (tyThingToIfaceDecl (ATyCon tycon))
1367 ppr_rules :: [CoreRule] -> SDoc
1368 ppr_rules [] = empty
1369 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1370 nest 4 (pprRules rs),
1373 ppr_gen_tycons [] = empty
1374 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1375 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]