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,
306 mg_binds = core_binds,
309 mg_rdr_env = emptyGlobalRdrEnv,
310 mg_fix_env = emptyFixityEnv,
311 mg_deprecs = NoDeprecs,
312 mg_foreign = NoStubs,
313 mg_hpc_info = noHpcInfo,
314 mg_dbg_sites = noDbgSites
317 tcCoreDump mod_guts ;
322 mkFakeGroup decls -- Rather clumsy; lots of unused fields
323 = emptyRdrGroup { hs_tyclds = decls }
327 %************************************************************************
329 Type-checking the top level of a module
331 %************************************************************************
334 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
335 -- Returns the variables free in the decls
336 -- Reason: solely to report unused imports and bindings
338 = do { -- Load the hi-boot interface for this module, if any
339 -- We do this now so that the boot_names can be passed
340 -- to tcTyAndClassDecls, because the boot_names are
341 -- automatically considered to be loop breakers
343 boot_iface <- tcHiBootIface mod ;
345 -- Do all the declarations
346 (tc_envs, lie) <- getLIE $ tc_rn_src_decls boot_iface decls ;
348 -- Finish simplifying class constraints
350 -- tcSimplifyTop deals with constant or ambiguous InstIds.
351 -- How could there be ambiguous ones? They can only arise if a
352 -- top-level decl falls under the monomorphism restriction
353 -- and no subsequent decl instantiates its type.
355 -- We do this after checkMain, so that we use the type info
356 -- thaat checkMain adds
358 -- We do it with both global and local env in scope:
359 -- * the global env exposes the instances to tcSimplifyTop
360 -- * the local env exposes the local Ids to tcSimplifyTop,
361 -- so that we get better error messages (monomorphism restriction)
362 traceTc (text "Tc8") ;
363 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
365 -- Backsubstitution. This must be done last.
366 -- Even tcSimplifyTop may do some unification.
367 traceTc (text "Tc9") ;
368 let { (tcg_env, _) = tc_envs
369 ; TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
370 tcg_rules = rules, tcg_fords = fords } = tcg_env
371 ; all_binds = binds `unionBags` inst_binds } ;
373 (bind_ids, binds', fords', rules') <- zonkTopDecls all_binds rules fords ;
375 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
376 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
379 tcg_fords = fords' } } ;
381 -- Make the new type env available to stuff slurped from interface files
382 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
384 -- Compare the hi-boot iface (if any) with the real thing
385 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
387 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
390 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
391 -- Loops around dealing with each top level inter-splice group
392 -- in turn, until it's dealt with the entire module
393 tc_rn_src_decls boot_details ds
394 = do { let { (first_group, group_tail) = findSplice ds } ;
395 -- If ds is [] we get ([], Nothing)
397 -- Deal with decls up to, but not including, the first splice
398 (tcg_env, rn_decls) <- checkNoErrs $ rnTopSrcDecls first_group ;
399 -- checkNoErrs: stop if renaming fails
401 (tcg_env, tcl_env) <- setGblEnv tcg_env $
402 tcTopSrcDecls boot_details rn_decls ;
404 -- If there is no splice, we're nearly done
405 setEnvs (tcg_env, tcl_env) $
407 Nothing -> do { tcg_env <- checkMain ; -- Check for `main'
408 return (tcg_env, tcl_env)
411 -- If there's a splice, we must carry on
412 Just (SpliceDecl splice_expr, rest_ds) -> do {
414 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
417 -- Rename the splice expression, and get its supporting decls
418 (rn_splice_expr, splice_fvs) <- checkNoErrs (rnLExpr splice_expr) ;
419 -- checkNoErrs: don't typecheck if renaming failed
420 rnDump (ppr rn_splice_expr) ;
422 -- Execute the splice
423 spliced_decls <- tcSpliceDecls rn_splice_expr ;
425 -- Glue them on the front of the remaining decls and loop
426 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
427 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
432 %************************************************************************
434 Compiling hs-boot source files, and
435 comparing the hi-boot interface with the real thing
437 %************************************************************************
440 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
441 tcRnHsBootDecls decls
442 = do { let { (first_group, group_tail) = findSplice decls }
445 Just stuff -> spliceInHsBootErr stuff
448 -- Rename the declarations
449 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
450 ; setGblEnv tcg_env $ do {
452 -- Todo: check no foreign decls, no rules, no default decls
454 -- Typecheck type/class decls
455 ; traceTc (text "Tc2")
456 ; let tycl_decls = hs_tyclds rn_group
457 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
458 ; setGblEnv tcg_env $ do {
460 -- Typecheck instance decls
461 ; traceTc (text "Tc3")
462 ; (tcg_env, inst_infos, _binds)
463 <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group)
464 ; setGblEnv tcg_env $ do {
466 -- Typecheck value declarations
467 ; traceTc (text "Tc5")
468 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
471 -- No simplification or zonking to do
472 ; traceTc (text "Tc7a")
473 ; gbl_env <- getGblEnv
475 -- Make the final type-env
476 -- Include the dfun_ids so that their type sigs
477 -- are written into the interface file
478 ; let { type_env0 = tcg_type_env gbl_env
479 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
480 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
481 ; dfun_ids = map iDFunId inst_infos }
482 ; return (gbl_env { tcg_type_env = type_env2 })
485 spliceInHsBootErr (SpliceDecl (L loc _), _)
486 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
489 Once we've typechecked the body of the module, we want to compare what
490 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
493 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
494 -- Compare the hi-boot file for this module (if there is one)
495 -- with the type environment we've just come up with
496 -- In the common case where there is no hi-boot file, the list
497 -- of boot_names is empty.
499 -- The bindings we return give bindings for the dfuns defined in the
500 -- hs-boot file, such as $fbEqT = $fEqT
503 (TcGblEnv { tcg_insts = local_insts, tcg_fam_insts = local_fam_insts,
504 tcg_type_env = local_type_env })
505 (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts,
506 md_types = boot_type_env })
507 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts)) ;
508 ; mapM_ check_one (typeEnvElts boot_type_env)
509 ; dfun_binds <- mapM check_inst boot_insts
510 ; unless (null boot_fam_insts) $
511 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
512 "instances in boot files yet...")
513 -- FIXME: Why? The actual comparison is not hard, but what would
514 -- be the equivalent to the dfun bindings returned for class
515 -- instances? We can't easily equate tycons...
516 ; return (unionManyBags dfun_binds) }
519 | isImplicitTyThing boot_thing = return ()
520 | name `elem` dfun_names = return ()
521 | isWiredInName name = return () -- No checking for wired-in names. In particular,
522 -- 'error' is handled by a rather gross hack
523 -- (see comments in GHC.Err.hs-boot)
524 | Just real_thing <- lookupTypeEnv local_type_env name
525 = do { let boot_decl = tyThingToIfaceDecl boot_thing
526 real_decl = tyThingToIfaceDecl real_thing
527 ; checkTc (checkBootDecl boot_decl real_decl)
528 (bootMisMatch boot_thing boot_decl real_decl) }
529 -- The easiest way to check compatibility is to convert to
530 -- iface syntax, where we already have good comparison functions
532 = addErrTc (missingBootThing boot_thing)
534 name = getName boot_thing
536 dfun_names = map getName boot_insts
539 = case [dfun | inst <- local_insts,
540 let dfun = instanceDFunId inst,
541 idType dfun `tcEqType` boot_inst_ty ] of
542 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
543 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
545 boot_dfun = instanceDFunId boot_inst
546 boot_inst_ty = idType boot_dfun
547 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
550 missingBootThing thing
551 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
552 bootMisMatch thing boot_decl real_decl
553 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
554 ptext SLIT("Decl") <+> ppr real_decl,
555 ptext SLIT("Boot file:") <+> ppr boot_decl]
558 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
562 %************************************************************************
564 Type-checking the top level of a module
566 %************************************************************************
568 tcRnGroup takes a bunch of top-level source-code declarations, and
570 * gets supporting declarations from interface files
573 * and augments the TcGblEnv with the results
575 In Template Haskell it may be called repeatedly for each group of
576 declarations. It expects there to be an incoming TcGblEnv in the
577 monad; it augments it and returns the new TcGblEnv.
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_insts, _), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1046 tcSimplifyInteractive lie_top ;
1048 let { all_expr_ty = mkForAllTys qtvs $
1049 mkFunTys (map (idType . instToId) dict_insts) $
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
1098 checkMods = ic_toplev_scope ic ++ ic_exports ic
1100 initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod checkMods)
1102 -- Get the export avail info and also load all orphan and family-instance
1103 -- modules. Finally, check that the family instances of all modules in the
1104 -- interactive context are consistent (these modules are in the second
1106 tcGetModuleExports :: Module -> [Module] -> TcM [AvailInfo]
1107 tcGetModuleExports mod directlyImpMods
1108 = do { let doc = ptext SLIT("context for compiling statements")
1109 ; iface <- initIfaceTcRn $ loadSysInterface doc mod
1111 -- Load any orphan-module and family instance-module
1112 -- interfaces, so their instances are visible.
1113 ; loadOrphanModules (dep_orphs (mi_deps iface)) False
1114 ; loadOrphanModules (dep_finsts (mi_deps iface)) True
1116 -- Check that the family instances of all directly loaded
1117 -- modules are consistent.
1118 ; checkFamInstConsistency (dep_finsts (mi_deps iface)) directlyImpMods
1120 ; ifaceExportNames (mi_exports iface)
1123 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1124 tcRnLookupRdrName hsc_env rdr_name
1125 = initTcPrintErrors hsc_env iNTERACTIVE $
1126 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1127 lookup_rdr_name rdr_name
1129 lookup_rdr_name rdr_name = do {
1130 -- If the identifier is a constructor (begins with an
1131 -- upper-case letter), then we need to consider both
1132 -- constructor and type class identifiers.
1133 let { rdr_names = dataTcOccs rdr_name } ;
1135 -- results :: [Either Messages Name]
1136 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1138 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1139 -- The successful lookups will be (Just name)
1140 let { (warns_s, good_names) = unzip [ (msgs, name)
1141 | (msgs, Just name) <- results] ;
1142 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1144 -- Fail if nothing good happened, else add warnings
1145 if null good_names then
1146 -- No lookup succeeded, so
1147 -- pick the first error message and report it
1148 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1149 -- while the other is "X is not in scope",
1150 -- we definitely want the former; but we might pick the latter
1151 do { addMessages (head errs_s) ; failM }
1152 else -- Add deprecation warnings
1153 mapM_ addMessages warns_s ;
1158 tcRnRecoverDataCon :: HscEnv -> a -> IO (Maybe DataCon)
1159 tcRnRecoverDataCon hsc_env a
1160 = initTcPrintErrors hsc_env iNTERACTIVE $
1161 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1162 do name <- recoverDataCon a
1163 tcLookupDataCon name
1165 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1166 tcRnLookupName hsc_env name
1167 = initTcPrintErrors hsc_env iNTERACTIVE $
1168 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1172 tcRnGetInfo :: HscEnv
1174 -> IO (Maybe (TyThing, Fixity, [Instance]))
1176 -- Used to implemnent :info in GHCi
1178 -- Look up a RdrName and return all the TyThings it might be
1179 -- A capitalised RdrName is given to us in the DataName namespace,
1180 -- but we want to treat it as *both* a data constructor
1181 -- *and* as a type or class constructor;
1182 -- hence the call to dataTcOccs, and we return up to two results
1183 tcRnGetInfo hsc_env name
1184 = initTcPrintErrors hsc_env iNTERACTIVE $
1185 let ictxt = hsc_IC hsc_env in
1186 setInteractiveContext hsc_env ictxt $ do
1188 -- Load the interface for all unqualified types and classes
1189 -- That way we will find all the instance declarations
1190 -- (Packages have not orphan modules, and we assume that
1191 -- in the home package all relevant modules are loaded.)
1192 loadUnqualIfaces ictxt
1194 thing <- tcLookupGlobal name
1195 fixity <- lookupFixityRn name
1196 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1197 return (thing, fixity, ispecs)
1199 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1200 -- Filter the instances by the ones whose tycons (or clases resp)
1201 -- are in scope unqualified. Otherwise we list a whole lot too many!
1202 lookupInsts print_unqual (AClass cls)
1203 = do { inst_envs <- tcGetInstEnvs
1205 | ispec <- classInstances inst_envs cls
1206 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1208 lookupInsts print_unqual (ATyCon tc)
1209 = do { eps <- getEps -- Load all instances for all classes that are
1210 -- in the type environment (which are all the ones
1211 -- we've seen in any interface file so far)
1212 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1214 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1215 , let dfun = instanceDFunId ispec
1217 , plausibleDFun print_unqual dfun ] }
1219 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1220 tc_name = tyConName tc
1222 lookupInsts print_unqual other = return []
1224 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1225 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1227 ok name | isBuiltInSyntax name = True
1228 | isExternalName name =
1229 isNothing $ fst print_unqual (nameModule name)
1233 loadUnqualIfaces :: InteractiveContext -> TcM ()
1234 -- Load the home module for everything that is in scope unqualified
1235 -- This is so that we can accurately report the instances for
1237 loadUnqualIfaces ictxt
1239 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1241 unqual_mods = [ nameModule name
1242 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1243 let name = gre_name gre,
1244 not (isInternalName name),
1245 isTcOcc (nameOccName name), -- Types and classes only
1246 unQualOK gre ] -- In scope unqualified
1247 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1251 %************************************************************************
1255 %************************************************************************
1258 rnDump :: SDoc -> TcRn ()
1259 -- Dump, with a banner, if -ddump-rn
1260 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1262 tcDump :: TcGblEnv -> TcRn ()
1264 = do { dflags <- getDOpts ;
1266 -- Dump short output if -ddump-types or -ddump-tc
1267 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1268 (dumpTcRn short_dump) ;
1270 -- Dump bindings if -ddump-tc
1271 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1274 short_dump = pprTcGblEnv env
1275 full_dump = pprLHsBinds (tcg_binds env)
1276 -- NB: foreign x-d's have undefined's in their types;
1277 -- hence can't show the tc_fords
1280 = do { dflags <- getDOpts ;
1281 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1282 (dumpTcRn (pprModGuts mod_guts)) ;
1284 -- Dump bindings if -ddump-tc
1285 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1287 full_dump = pprCoreBindings (mg_binds mod_guts)
1289 -- It's unpleasant having both pprModGuts and pprModDetails here
1290 pprTcGblEnv :: TcGblEnv -> SDoc
1291 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1293 tcg_fam_insts = fam_insts,
1295 tcg_imports = imports })
1296 = vcat [ ppr_types insts type_env
1297 , ppr_tycons fam_insts type_env
1299 , ppr_fam_insts fam_insts
1300 , vcat (map ppr rules)
1301 , ppr_gen_tycons (typeEnvTyCons type_env)
1302 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1303 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1305 pprModGuts :: ModGuts -> SDoc
1306 pprModGuts (ModGuts { mg_types = type_env,
1308 = vcat [ ppr_types [] type_env,
1311 ppr_types :: [Instance] -> TypeEnv -> SDoc
1312 ppr_types insts type_env
1313 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1315 dfun_ids = map instanceDFunId insts
1316 ids = [id | id <- typeEnvIds type_env, want_sig id]
1317 want_sig id | opt_PprStyle_Debug = True
1318 | otherwise = isLocalId id &&
1319 isExternalName (idName id) &&
1320 not (id `elem` dfun_ids)
1321 -- isLocalId ignores data constructors, records selectors etc.
1322 -- The isExternalName ignores local dictionary and method bindings
1323 -- that the type checker has invented. Top-level user-defined things
1324 -- have External names.
1326 ppr_tycons :: [FamInst] -> TypeEnv -> SDoc
1327 ppr_tycons fam_insts type_env
1328 = text "TYPE CONSTRUCTORS" $$ nest 4 (ppr_tydecls tycons)
1330 fi_tycons = map famInstTyCon fam_insts
1331 tycons = [tycon | tycon <- typeEnvTyCons type_env, want_tycon tycon]
1332 want_tycon tycon | opt_PprStyle_Debug = True
1333 | otherwise = not (isImplicitTyCon tycon) &&
1334 isExternalName (tyConName tycon) &&
1335 not (tycon `elem` fi_tycons)
1337 ppr_insts :: [Instance] -> SDoc
1338 ppr_insts [] = empty
1339 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1341 ppr_fam_insts :: [FamInst] -> SDoc
1342 ppr_fam_insts [] = empty
1343 ppr_fam_insts fam_insts =
1344 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1346 ppr_sigs :: [Var] -> SDoc
1348 -- Print type signatures; sort by OccName
1349 = vcat (map ppr_sig (sortLe le_sig ids))
1351 le_sig id1 id2 = getOccName id1 <= getOccName id2
1352 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1354 ppr_tydecls :: [TyCon] -> SDoc
1356 -- Print type constructor info; sort by OccName
1357 = vcat (map ppr_tycon (sortLe le_sig tycons))
1359 le_sig tycon1 tycon2 = getOccName tycon1 <= getOccName tycon2
1361 | isCoercionTyCon tycon = ptext SLIT("coercion") <+> ppr tycon
1362 | otherwise = ppr (tyThingToIfaceDecl (ATyCon tycon))
1364 ppr_rules :: [CoreRule] -> SDoc
1365 ppr_rules [] = empty
1366 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1367 nest 4 (pprRules rs),
1370 ppr_gen_tycons [] = empty
1371 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1372 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]