2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
5 \section[TcModule]{Typechecking a whole module}
10 tcRnStmt, tcRnExpr, tcRnType,
21 #include "HsVersions.h"
25 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
84 import {- Kind parts of -} Type
93 import Control.Monad ( unless )
94 import Data.Maybe ( isJust )
99 %************************************************************************
101 Typecheck and rename a module
103 %************************************************************************
109 -> Bool -- True <=> save renamed syntax
110 -> Located (HsModule RdrName)
111 -> IO (Messages, Maybe TcGblEnv)
113 tcRnModule hsc_env hsc_src save_rn_syntax
114 (L loc (HsModule maybe_mod export_ies
115 import_decls local_decls mod_deprec _ module_info maybe_doc))
116 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
118 let { this_pkg = thisPackage (hsc_dflags hsc_env) ;
119 this_mod = case maybe_mod of
120 Nothing -> mAIN -- 'module M where' is omitted
121 Just (L _ mod) -> mkModule this_pkg mod } ;
124 initTc hsc_env hsc_src this_mod $
127 -- Deal with imports;
128 (rn_imports, rdr_env, imports) <- rnImports import_decls ;
130 let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)
131 ; dep_mods = imp_dep_mods imports
133 -- We want instance declarations from all home-package
134 -- modules below this one, including boot modules, except
135 -- ourselves. The 'except ourselves' is so that we don't
136 -- get the instances from this module's hs-boot file
137 ; want_instances :: ModuleName -> Bool
138 ; want_instances mod = mod `elemUFM` dep_mods
139 && mod /= moduleName this_mod
140 ; home_insts = hptInstances hsc_env want_instances
143 -- Record boot-file info in the EPS, so that it's
144 -- visible to loadHiBootInterface in tcRnSrcDecls,
145 -- and any other incrementally-performed imports
146 updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
148 -- Update the gbl env
150 gbl { tcg_rdr_env = plusOccEnv (tcg_rdr_env gbl) rdr_env,
151 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts,
152 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
153 tcg_rn_imports = if save_rn_syntax then
157 tcg_rn_decls = if save_rn_syntax then
163 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
164 -- Fail if there are any errors so far
165 -- The error printing (if needed) takes advantage
166 -- of the tcg_env we have now set
167 traceIf (text "rdr_env: " <+> ppr rdr_env) ;
170 -- Load any orphan-module interfaces, so that
171 -- their rules and instance decls will be found
172 loadOrphanModules (imp_orphs imports) ;
174 traceRn (text "rn1a") ;
175 -- Rename and type check the declarations
176 tcg_env <- if isHsBoot hsc_src then
177 tcRnHsBootDecls local_decls
179 tcRnSrcDecls local_decls ;
180 setGblEnv tcg_env $ do {
182 traceRn (text "rn3") ;
184 -- Report the use of any deprecated things
185 -- We do this before processsing the export list so
186 -- that we don't bleat about re-exporting a deprecated
187 -- thing (especially via 'module Foo' export item)
188 -- Only uses in the body of the module are complained about
189 reportDeprecations (hsc_dflags hsc_env) tcg_env ;
191 -- Process the export list
192 (rn_exports, exports) <- rnExports (isJust maybe_mod) export_ies ;
194 -- Rename the Haddock documentation header
195 rn_module_doc <- rnMbHsDoc maybe_doc ;
197 -- Rename the Haddock module info
198 rn_description <- rnMbHsDoc (hmi_description module_info) ;
199 let { rn_module_info = module_info { hmi_description = rn_description } } ;
201 -- Check whether the entire module is deprecated
202 -- This happens only once per module
203 let { mod_deprecs = checkModDeprec mod_deprec } ;
205 -- Add exports and deprecations to envt
206 let { final_env = tcg_env { tcg_exports = exports,
207 tcg_rn_exports = if save_rn_syntax then
210 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly (availsToNameSet exports),
211 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
213 tcg_doc = rn_module_doc,
214 tcg_hmi = rn_module_info
216 -- A module deprecation over-rides the earlier ones
219 -- Report unused names
220 reportUnusedNames export_ies final_env ;
222 -- Dump output and return
229 %************************************************************************
231 Type-checking external-core modules
233 %************************************************************************
236 tcRnExtCore :: HscEnv
238 -> IO (Messages, Maybe ModGuts)
239 -- Nothing => some error occurred
241 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
242 -- The decls are IfaceDecls; all names are original names
243 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
245 initTc hsc_env ExtCoreFile this_mod $ do {
247 let { ldecls = map noLoc decls } ;
249 -- Deal with the type declarations; first bring their stuff
250 -- into scope, then rname them, then type check them
251 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
253 setGblEnv tcg_env $ do {
255 rn_decls <- rnTyClDecls ldecls ;
258 -- Dump trace of renaming part
259 rnDump (ppr rn_decls) ;
261 -- Typecheck them all together so that
262 -- any mutually recursive types are done right
263 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
264 -- Make the new type env available to stuff slurped from interface files
266 setGblEnv tcg_env $ do {
268 -- Now the core bindings
269 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
273 bndrs = bindersOfBinds core_binds ;
274 my_exports = map (Avail . idName) bndrs ;
275 -- ToDo: export the data types also?
277 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
279 mod_guts = ModGuts { mg_module = this_mod,
281 mg_usages = [], -- ToDo: compute usage
282 mg_dir_imps = [], -- ??
283 mg_deps = noDependencies, -- ??
284 mg_exports = my_exports,
285 mg_types = final_type_env,
286 mg_insts = tcg_insts tcg_env,
287 mg_fam_insts = tcg_fam_insts tcg_env,
289 mg_binds = core_binds,
292 mg_rdr_env = emptyGlobalRdrEnv,
293 mg_fix_env = emptyFixityEnv,
294 mg_deprecs = NoDeprecs,
298 tcCoreDump mod_guts ;
303 mkFakeGroup decls -- Rather clumsy; lots of unused fields
304 = emptyRdrGroup { hs_tyclds = decls }
308 %************************************************************************
310 Type-checking the top level of a module
312 %************************************************************************
315 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
316 -- Returns the variables free in the decls
317 -- Reason: solely to report unused imports and bindings
319 = do { -- Load the hi-boot interface for this module, if any
320 -- We do this now so that the boot_names can be passed
321 -- to tcTyAndClassDecls, because the boot_names are
322 -- automatically considered to be loop breakers
324 boot_iface <- tcHiBootIface mod ;
326 -- Do all the declarations
327 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_iface decls) ;
329 -- tcSimplifyTop deals with constant or ambiguous InstIds.
330 -- How could there be ambiguous ones? They can only arise if a
331 -- top-level decl falls under the monomorphism
332 -- restriction, and no subsequent decl instantiates its
333 -- type. (Usually, ambiguous type variables are resolved
334 -- during the generalisation step.)
335 traceTc (text "Tc8") ;
336 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
337 -- Setting the global env exposes the instances to tcSimplifyTop
338 -- Setting the local env exposes the local Ids to tcSimplifyTop,
339 -- so that we get better error messages (monomorphism restriction)
341 -- Backsubstitution. This must be done last.
342 -- Even tcSimplifyTop may do some unification.
343 traceTc (text "Tc9") ;
344 let { (tcg_env, _) = tc_envs ;
345 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
346 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
348 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
351 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
352 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
355 tcg_fords = fords' } } ;
357 -- Make the new type env available to stuff slurped from interface files
358 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
360 -- Compare the hi-boot iface (if any) with the real thing
361 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
363 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
366 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
367 -- Loops around dealing with each top level inter-splice group
368 -- in turn, until it's dealt with the entire module
369 tc_rn_src_decls boot_details ds
370 = do { let { (first_group, group_tail) = findSplice ds } ;
371 -- If ds is [] we get ([], Nothing)
373 -- Type check the decls up to, but not including, the first splice
374 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_details first_group ;
376 -- Bale out if errors; for example, error recovery when checking
377 -- the RHS of 'main' can mean that 'main' is not in the envt for
378 -- the subsequent checkMain test
383 -- If there is no splice, we're nearly done
385 Nothing -> do { -- Last thing: check for `main'
386 tcg_env <- checkMain ;
387 return (tcg_env, tcl_env)
390 -- If there's a splice, we must carry on
391 Just (SpliceDecl splice_expr, rest_ds) -> do {
393 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
396 -- Rename the splice expression, and get its supporting decls
397 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
398 failIfErrsM ; -- Don't typecheck if renaming failed
399 rnDump (ppr rn_splice_expr) ;
401 -- Execute the splice
402 spliced_decls <- tcSpliceDecls rn_splice_expr ;
404 -- Glue them on the front of the remaining decls and loop
405 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
406 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
411 %************************************************************************
413 Compiling hs-boot source files, and
414 comparing the hi-boot interface with the real thing
416 %************************************************************************
419 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
420 tcRnHsBootDecls decls
421 = do { let { (first_group, group_tail) = findSplice decls }
424 Just stuff -> spliceInHsBootErr stuff
427 -- Rename the declarations
428 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
429 ; setGblEnv tcg_env $ do {
431 -- Todo: check no foreign decls, no rules, no default decls
433 -- Typecheck type/class decls
434 ; traceTc (text "Tc2")
435 ; let tycl_decls = hs_tyclds rn_group
436 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
437 ; setGblEnv tcg_env $ do {
439 -- Typecheck instance decls
440 ; traceTc (text "Tc3")
441 ; (tcg_env, inst_infos, _binds)
442 <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group)
443 ; setGblEnv tcg_env $ do {
445 -- Typecheck value declarations
446 ; traceTc (text "Tc5")
447 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
450 -- No simplification or zonking to do
451 ; traceTc (text "Tc7a")
452 ; gbl_env <- getGblEnv
454 -- Make the final type-env
455 -- Include the dfun_ids so that their type sigs get
456 -- are written into the interface file
457 ; let { type_env0 = tcg_type_env gbl_env
458 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
459 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
460 ; dfun_ids = map iDFunId inst_infos }
461 ; return (gbl_env { tcg_type_env = type_env2 })
464 spliceInHsBootErr (SpliceDecl (L loc _), _)
465 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
468 Once we've typechecked the body of the module, we want to compare what
469 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
472 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
473 -- Compare the hi-boot file for this module (if there is one)
474 -- with the type environment we've just come up with
475 -- In the common case where there is no hi-boot file, the list
476 -- of boot_names is empty.
478 -- The bindings we return give bindings for the dfuns defined in the
479 -- hs-boot file, such as $fbEqT = $fEqT
482 (TcGblEnv { tcg_insts = local_insts, tcg_fam_insts = local_fam_insts,
483 tcg_type_env = local_type_env, tcg_imports = imports })
484 (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts,
485 md_types = boot_type_env })
486 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts)) ;
487 ; mapM_ check_one (typeEnvElts boot_type_env)
488 ; dfun_binds <- mapM check_inst boot_insts
489 ; unless (null boot_fam_insts) $
490 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
491 "instances in boot files yet...")
492 -- FIXME: Why? The actual comparison is not hard, but what would
493 -- be the equivalent to the dfun bindings returned for class
494 -- instances? We can't easily equate tycons...
495 ; return (unionManyBags dfun_binds) }
500 | Just real_thing <- lookupTypeEnv local_type_env name
501 = do { let boot_decl = tyThingToIfaceDecl boot_thing
502 real_decl = tyThingToIfaceDecl real_thing
503 ; checkTc (checkBootDecl boot_decl real_decl)
504 (bootMisMatch boot_thing boot_decl real_decl) }
505 -- The easiest way to check compatibility is to convert to
506 -- iface syntax, where we already have good comparison functions
508 = addErrTc (missingBootThing boot_thing)
510 name = getName boot_thing
512 avail_env = imp_parent imports
513 is_implicit name = case lookupNameEnv avail_env name of
514 Just (AvailTC tc _) | tc /= name -> True
517 no_check name = isWiredInName name -- No checking for wired-in names. In particular,
518 -- 'error' is handled by a rather gross hack
519 -- (see comments in GHC.Err.hs-boot)
520 || name `elem` dfun_names
521 || is_implicit name -- Has a parent, which we'll check
523 dfun_names = map getName boot_insts
526 = case [dfun | inst <- local_insts,
527 let dfun = instanceDFunId inst,
528 idType dfun `tcEqType` boot_inst_ty ] of
529 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
530 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
532 boot_dfun = instanceDFunId boot_inst
533 boot_inst_ty = idType boot_dfun
534 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
537 missingBootThing thing
538 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
539 bootMisMatch thing boot_decl real_decl
540 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
541 ptext SLIT("Decl") <+> ppr real_decl,
542 ptext SLIT("Boot file:") <+> ppr boot_decl]
545 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
549 %************************************************************************
551 Type-checking the top level of a module
553 %************************************************************************
555 tcRnGroup takes a bunch of top-level source-code declarations, and
557 * gets supporting declarations from interface files
560 * and augments the TcGblEnv with the results
562 In Template Haskell it may be called repeatedly for each group of
563 declarations. It expects there to be an incoming TcGblEnv in the
564 monad; it augments it and returns the new TcGblEnv.
567 tcRnGroup :: ModDetails -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
568 -- Returns the variables free in the decls, for unused-binding reporting
569 tcRnGroup boot_details decls
570 = do { -- Rename the declarations
571 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
572 setGblEnv tcg_env $ do {
574 -- Typecheck the declarations
575 tcTopSrcDecls boot_details rn_decls
578 ------------------------------------------------
579 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
581 = do { -- Bring top level binders into scope
582 tcg_env <- importsFromLocalDecls group ;
583 setGblEnv tcg_env $ do {
585 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
587 -- Rename the source decls
588 (tcg_env, rn_decls) <- rnSrcDecls group ;
591 -- save the renamed syntax, if we want it
593 | Just grp <- tcg_rn_decls tcg_env
594 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
598 -- Dump trace of renaming part
599 rnDump (ppr rn_decls) ;
601 return (tcg_env', rn_decls)
604 ------------------------------------------------
605 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
606 tcTopSrcDecls boot_details
607 (HsGroup { hs_tyclds = tycl_decls,
608 hs_instds = inst_decls,
609 hs_derivds = deriv_decls,
610 hs_fords = foreign_decls,
611 hs_defds = default_decls,
612 hs_ruleds = rule_decls,
613 hs_valds = val_binds })
614 = do { -- Type-check the type and class decls, and all imported decls
615 -- The latter come in via tycl_decls
616 traceTc (text "Tc2") ;
618 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
619 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
620 -- an error we'd better stop now, to avoid a cascade
622 -- Make these type and class decls available to stuff slurped from interface files
623 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
626 setGblEnv tcg_env $ do {
627 -- Source-language instances, including derivings,
628 -- and import the supporting declarations
629 traceTc (text "Tc3") ;
630 (tcg_env, inst_infos, deriv_binds)
631 <- tcInstDecls1 tycl_decls inst_decls deriv_decls;
632 setGblEnv tcg_env $ do {
634 -- Foreign import declarations next. No zonking necessary
635 -- here; we can tuck them straight into the global environment.
636 traceTc (text "Tc4") ;
637 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
638 tcExtendGlobalValEnv fi_ids $ do {
640 -- Default declarations
641 traceTc (text "Tc4a") ;
642 default_tys <- tcDefaults default_decls ;
643 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
645 -- Value declarations next
646 -- We also typecheck any extra binds that came out
647 -- of the "deriving" process (deriv_binds)
648 traceTc (text "Tc5") ;
649 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
650 setLclTypeEnv tcl_env $ do {
652 -- Second pass over class and instance declarations,
653 traceTc (text "Tc6") ;
654 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
655 showLIE (text "after instDecls2") ;
658 -- They need to be zonked, so we return them
659 traceTc (text "Tc7") ;
660 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
663 rules <- tcRules rule_decls ;
666 traceTc (text "Tc7a") ;
667 tcg_env <- getGblEnv ;
668 let { all_binds = tc_val_binds `unionBags`
669 inst_binds `unionBags`
672 -- Extend the GblEnv with the (as yet un-zonked)
673 -- bindings, rules, foreign decls
674 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
675 tcg_rules = tcg_rules tcg_env ++ rules,
676 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
677 return (tcg_env', tcl_env)
682 %************************************************************************
686 %************************************************************************
689 checkMain :: TcM TcGblEnv
690 -- If we are in module Main, check that 'main' is defined.
692 = do { ghc_mode <- getGhcMode ;
693 tcg_env <- getGblEnv ;
695 let { main_mod = mainModIs dflags ;
696 main_fn = case mainFunIs dflags of {
697 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
698 Nothing -> main_RDR_Unqual } } ;
700 check_main ghc_mode tcg_env main_mod main_fn
704 check_main ghc_mode tcg_env main_mod main_fn
706 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
710 = addErrCtxt mainCtxt $
711 do { mb_main <- lookupSrcOcc_maybe main_fn
712 -- Check that 'main' is in scope
713 -- It might be imported from another module!
715 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
719 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
720 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
721 -- :Main.main :: IO () = runMainIO main
723 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
726 -- The function that the RTS invokes is always :Main.main,
727 -- which we call root_main_id.
728 -- (Because GHC allows the user to have a module not called
729 -- Main as the main module, we can't rely on the main function
730 -- being called "Main.main". That's why root_main_id has a fixed
732 -- We also make root_main_id an implicit Id, by making main_name
733 -- its parent (hence (Just main_name)). That has the effect
734 -- of preventing its type and unfolding from getting out into
735 -- the interface file. Otherwise we can end up with two defns
736 -- for 'main' in the interface file!
738 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
739 (mkVarOccFS FSLIT("main"))
740 (getSrcLoc main_name)
741 ; root_main_id = Id.mkExportedLocalId root_main_name ty
742 ; main_bind = noLoc (VarBind root_main_id main_expr) }
744 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
746 tcg_dus = tcg_dus tcg_env
747 `plusDU` usesOnly (unitFV main_name)
748 -- Record the use of 'main', so that we don't
749 -- complain about it being defined but not used
753 mod = tcg_mod tcg_env
755 complain_no_main | ghc_mode == Interactive = return ()
756 | otherwise = failWithTc noMainMsg
757 -- In interactive mode, don't worry about the absence of 'main'
758 -- In other modes, fail altogether, so that we don't go on
759 -- and complain a second time when processing the export list.
761 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
762 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
763 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
766 %*********************************************************
770 %*********************************************************
774 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
775 setInteractiveContext hsc_env icxt thing_inside
777 -- Initialise the tcg_inst_env with instances
778 -- from all home modules. This mimics the more selective
779 -- call to hptInstances in tcRnModule
780 dfuns = hptInstances hsc_env (\mod -> True)
782 updGblEnv (\env -> env {
783 tcg_rdr_env = ic_rn_gbl_env icxt,
784 tcg_type_env = ic_type_env icxt,
785 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
787 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
789 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
796 -> InteractiveContext
798 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
799 -- The returned [Name] is the same as the input except for
800 -- ExprStmt, in which case the returned [Name] is [itName]
802 -- The returned TypecheckedHsExpr is of type IO [ () ],
803 -- a list of the bound values, coerced to ().
805 tcRnStmt hsc_env ictxt rdr_stmt
806 = initTcPrintErrors hsc_env iNTERACTIVE $
807 setInteractiveContext hsc_env ictxt $ do {
809 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
810 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
811 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
814 -- The real work is done here
815 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
816 zonked_expr <- zonkTopLExpr tc_expr ;
817 zonked_ids <- zonkTopBndrs bound_ids ;
819 -- None of the Ids should be of unboxed type, because we
820 -- cast them all to HValues in the end!
821 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
823 traceTc (text "tcs 1") ;
824 let { -- (a) Make all the bound ids "global" ids, now that
825 -- they're notionally top-level bindings. This is
826 -- important: otherwise when we come to compile an expression
827 -- using these ids later, the byte code generator will consider
828 -- the occurrences to be free rather than global.
830 -- (b) Tidy their types; this is important, because :info may
831 -- ask to look at them, and :info expects the things it looks
832 -- up to have tidy types
833 global_ids = map globaliseAndTidy zonked_ids ;
835 -- Update the interactive context
836 rn_env = ic_rn_local_env ictxt ;
837 type_env = ic_type_env ictxt ;
839 bound_names = map idName global_ids ;
840 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
842 {- ---------------------------------------------
843 At one stage I removed any shadowed bindings from the type_env;
844 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
845 However, with Template Haskell they aren't necessarily inaccessible. Consider this
847 Prelude> let f n = n * 2 :: Int
848 Prelude> fName <- runQ [| f |]
849 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
851 Prelude> let f n = n * 3 :: Int
852 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
853 In the last line we use 'fName', which resolves to the *first* 'f'
854 in scope. If we delete it from the type env, GHCi crashes because
855 it doesn't expect that.
857 Hence this code is commented out
859 shadowed = [ n | name <- bound_names,
860 let rdr_name = mkRdrUnqual (nameOccName name),
861 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
862 filtered_type_env = delListFromNameEnv type_env shadowed ;
863 -------------------------------------------------- -}
865 new_type_env = extendTypeEnvWithIds type_env global_ids ;
866 new_ic = ictxt { ic_rn_local_env = new_rn_env,
867 ic_type_env = new_type_env }
870 dumpOptTcRn Opt_D_dump_tc
871 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
872 text "Typechecked expr" <+> ppr zonked_expr]) ;
874 returnM (new_ic, bound_names, zonked_expr)
877 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
878 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
880 globaliseAndTidy :: Id -> Id
882 -- Give the Id a Global Name, and tidy its type
883 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
885 tidy_type = tidyTopType (idType id)
888 Here is the grand plan, implemented in tcUserStmt
890 What you type The IO [HValue] that hscStmt returns
891 ------------- ------------------------------------
892 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
895 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
898 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
899 [NB: result not printed] bindings: [it]
901 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
902 result showable) bindings: [it]
904 expr (of non-IO type,
905 result not showable) ==> error
909 ---------------------------
910 type PlanResult = ([Id], LHsExpr Id)
911 type Plan = TcM PlanResult
913 runPlans :: [Plan] -> TcM PlanResult
914 -- Try the plans in order. If one fails (by raising an exn), try the next.
915 -- If one succeeds, take it.
916 runPlans [] = panic "runPlans"
918 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
921 mkPlan :: LStmt Name -> TcM PlanResult
922 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
923 = do { uniq <- newUnique -- is treated very specially
924 ; let fresh_it = itName uniq
925 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
926 matches = [mkMatch [] expr emptyLocalBinds]
927 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
928 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
929 (HsVar bindIOName) noSyntaxExpr
930 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
931 (HsVar thenIOName) placeHolderType
934 -- [it <- e; print it] but not if it::()
936 -- [let it = e; print it]
937 ; runPlans [ -- Plan A
938 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
939 ; it_ty <- zonkTcType (idType it_id)
940 ; ifM (isUnitTy it_ty) failM
943 -- Plan B; a naked bind statment
944 tcGhciStmts [bind_stmt],
946 -- Plan C; check that the let-binding is typeable all by itself.
947 -- If not, fail; if so, try to print it.
948 -- The two-step process avoids getting two errors: one from
949 -- the expression itself, and one from the 'print it' part
950 -- This two-step story is very clunky, alas
951 do { checkNoErrs (tcGhciStmts [let_stmt])
952 --- checkNoErrs defeats the error recovery of let-bindings
953 ; tcGhciStmts [let_stmt, print_it] }
956 mkPlan stmt@(L loc (BindStmt {}))
957 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
958 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
959 (HsVar thenIOName) placeHolderType
961 ; print_bind_result <- doptM Opt_PrintBindResult
962 ; let print_plan = do
963 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
964 ; v_ty <- zonkTcType (idType v_id)
965 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
969 -- [stmt; print v] but not if v::()
971 ; runPlans ((if print_bind_result then [print_plan] else []) ++
972 [tcGhciStmts [stmt]])
978 ---------------------------
979 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
981 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
982 ret_id <- tcLookupId returnIOName ; -- return @ IO
984 io_ty = mkTyConApp ioTyCon [] ;
985 ret_ty = mkListTy unitTy ;
986 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
987 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
988 (emptyRefinement, io_ret_ty) ;
990 names = map unLoc (collectLStmtsBinders stmts) ;
992 -- mk_return builds the expression
993 -- returnIO @ [()] [coerce () x, .., coerce () z]
995 -- Despite the inconvenience of building the type applications etc,
996 -- this *has* to be done in type-annotated post-typecheck form
997 -- because we are going to return a list of *polymorphic* values
998 -- coerced to type (). If we built a *source* stmt
999 -- return [coerce x, ..., coerce z]
1000 -- then the type checker would instantiate x..z, and we wouldn't
1001 -- get their *polymorphic* values. (And we'd get ambiguity errs
1002 -- if they were overloaded, since they aren't applied to anything.)
1003 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
1004 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1005 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1009 -- OK, we're ready to typecheck the stmts
1010 traceTc (text "tcs 2") ;
1011 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1012 mappM tcLookupId names ;
1013 -- Look up the names right in the middle,
1014 -- where they will all be in scope
1016 -- Simplify the context
1017 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1018 -- checkNoErrs ensures that the plan fails if context redn fails
1020 return (ids, mkHsDictLet const_binds $
1021 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1026 tcRnExpr just finds the type of an expression
1030 -> InteractiveContext
1033 tcRnExpr hsc_env ictxt rdr_expr
1034 = initTcPrintErrors hsc_env iNTERACTIVE $
1035 setInteractiveContext hsc_env ictxt $ do {
1037 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1040 -- Now typecheck the expression;
1041 -- it might have a rank-2 type (e.g. :t runST)
1042 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1043 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1044 tcSimplifyInteractive lie_top ;
1045 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
1047 let { all_expr_ty = mkForAllTys qtvs' $
1048 mkFunTys (map idType dict_ids) $
1050 zonkTcType all_expr_ty
1053 smpl_doc = ptext SLIT("main expression")
1056 tcRnType just finds the kind of a type
1060 -> InteractiveContext
1063 tcRnType hsc_env ictxt rdr_type
1064 = initTcPrintErrors hsc_env iNTERACTIVE $
1065 setInteractiveContext hsc_env ictxt $ do {
1067 rn_type <- rnLHsType doc rdr_type ;
1070 -- Now kind-check the type
1071 (ty', kind) <- kcHsType rn_type ;
1075 doc = ptext SLIT("In GHCi input")
1081 %************************************************************************
1083 More GHCi stuff, to do with browsing and getting info
1085 %************************************************************************
1089 -- ASSUMES that the module is either in the HomePackageTable or is
1090 -- a package module with an interface on disk. If neither of these is
1091 -- true, then the result will be an error indicating the interface
1092 -- could not be found.
1093 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1094 getModuleExports hsc_env mod
1095 = initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod)
1097 tcGetModuleExports :: Module -> TcM [AvailInfo]
1098 tcGetModuleExports mod = do
1099 let doc = ptext SLIT("context for compiling statements")
1100 iface <- initIfaceTcRn $ loadSysInterface doc mod
1101 loadOrphanModules (dep_orphs (mi_deps iface))
1102 -- Load any orphan-module interfaces,
1103 -- so their instances are visible
1104 ifaceExportNames (mi_exports iface)
1106 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1107 tcRnLookupRdrName hsc_env rdr_name
1108 = initTcPrintErrors hsc_env iNTERACTIVE $
1109 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1110 lookup_rdr_name rdr_name
1112 lookup_rdr_name rdr_name = do {
1113 -- If the identifier is a constructor (begins with an
1114 -- upper-case letter), then we need to consider both
1115 -- constructor and type class identifiers.
1116 let { rdr_names = dataTcOccs rdr_name } ;
1118 -- results :: [Either Messages Name]
1119 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1121 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1122 -- The successful lookups will be (Just name)
1123 let { (warns_s, good_names) = unzip [ (msgs, name)
1124 | (msgs, Just name) <- results] ;
1125 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1127 -- Fail if nothing good happened, else add warnings
1128 if null good_names then
1129 -- No lookup succeeded, so
1130 -- pick the first error message and report it
1131 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1132 -- while the other is "X is not in scope",
1133 -- we definitely want the former; but we might pick the latter
1134 do { addMessages (head errs_s) ; failM }
1135 else -- Add deprecation warnings
1136 mapM_ addMessages warns_s ;
1142 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1143 tcRnLookupName hsc_env name
1144 = initTcPrintErrors hsc_env iNTERACTIVE $
1145 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1149 tcRnGetInfo :: HscEnv
1151 -> IO (Maybe (TyThing, Fixity, [Instance]))
1153 -- Used to implemnent :info in GHCi
1155 -- Look up a RdrName and return all the TyThings it might be
1156 -- A capitalised RdrName is given to us in the DataName namespace,
1157 -- but we want to treat it as *both* a data constructor
1158 -- *and* as a type or class constructor;
1159 -- hence the call to dataTcOccs, and we return up to two results
1160 tcRnGetInfo hsc_env name
1161 = initTcPrintErrors hsc_env iNTERACTIVE $
1162 let ictxt = hsc_IC hsc_env in
1163 setInteractiveContext hsc_env ictxt $ do
1165 -- Load the interface for all unqualified types and classes
1166 -- That way we will find all the instance declarations
1167 -- (Packages have not orphan modules, and we assume that
1168 -- in the home package all relevant modules are loaded.)
1169 loadUnqualIfaces ictxt
1171 thing <- tcLookupGlobal name
1172 fixity <- lookupFixityRn name
1173 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1174 return (thing, fixity, ispecs)
1177 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1178 -- Filter the instances by the ones whose tycons (or clases resp)
1179 -- are in scope unqualified. Otherwise we list a whole lot too many!
1180 lookupInsts print_unqual (AClass cls)
1181 = do { inst_envs <- tcGetInstEnvs
1183 | ispec <- classInstances inst_envs cls
1184 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1186 lookupInsts print_unqual (ATyCon tc)
1187 = do { eps <- getEps -- Load all instances for all classes that are
1188 -- in the type environment (which are all the ones
1189 -- we've seen in any interface file so far)
1190 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1192 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1193 , let dfun = instanceDFunId ispec
1195 , plausibleDFun print_unqual dfun ] }
1197 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1198 tc_name = tyConName tc
1200 lookupInsts print_unqual other = return []
1202 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1203 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1205 ok name | isBuiltInSyntax name = True
1206 | isExternalName name =
1207 isNothing $ fst print_unqual (nameModule name)
1211 loadUnqualIfaces :: InteractiveContext -> TcM ()
1212 -- Load the home module for everything that is in scope unqualified
1213 -- This is so that we can accurately report the instances for
1215 loadUnqualIfaces ictxt
1217 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1219 unqual_mods = [ nameModule name
1220 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1221 let name = gre_name gre,
1222 not (isInternalName name),
1223 isTcOcc (nameOccName name), -- Types and classes only
1224 unQualOK gre ] -- In scope unqualified
1225 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1229 %************************************************************************
1233 %************************************************************************
1236 rnDump :: SDoc -> TcRn ()
1237 -- Dump, with a banner, if -ddump-rn
1238 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1240 tcDump :: TcGblEnv -> TcRn ()
1242 = do { dflags <- getDOpts ;
1244 -- Dump short output if -ddump-types or -ddump-tc
1245 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1246 (dumpTcRn short_dump) ;
1248 -- Dump bindings if -ddump-tc
1249 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1252 short_dump = pprTcGblEnv env
1253 full_dump = pprLHsBinds (tcg_binds env)
1254 -- NB: foreign x-d's have undefined's in their types;
1255 -- hence can't show the tc_fords
1258 = do { dflags <- getDOpts ;
1259 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1260 (dumpTcRn (pprModGuts mod_guts)) ;
1262 -- Dump bindings if -ddump-tc
1263 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1265 full_dump = pprCoreBindings (mg_binds mod_guts)
1267 -- It's unpleasant having both pprModGuts and pprModDetails here
1268 pprTcGblEnv :: TcGblEnv -> SDoc
1269 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1271 tcg_fam_insts = fam_insts,
1273 tcg_imports = imports })
1274 = vcat [ ppr_types insts type_env
1276 , ppr_fam_insts fam_insts
1277 , vcat (map ppr rules)
1278 , ppr_gen_tycons (typeEnvTyCons type_env)
1279 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1280 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1282 pprModGuts :: ModGuts -> SDoc
1283 pprModGuts (ModGuts { mg_types = type_env,
1285 = vcat [ ppr_types [] type_env,
1288 ppr_types :: [Instance] -> TypeEnv -> SDoc
1289 ppr_types insts type_env
1290 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1292 dfun_ids = map instanceDFunId insts
1293 ids = [id | id <- typeEnvIds type_env, want_sig id]
1294 want_sig id | opt_PprStyle_Debug = True
1295 | otherwise = isLocalId id &&
1296 isExternalName (idName id) &&
1297 not (id `elem` dfun_ids)
1298 -- isLocalId ignores data constructors, records selectors etc.
1299 -- The isExternalName ignores local dictionary and method bindings
1300 -- that the type checker has invented. Top-level user-defined things
1301 -- have External names.
1303 ppr_insts :: [Instance] -> SDoc
1304 ppr_insts [] = empty
1305 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1307 ppr_fam_insts :: [FamInst] -> SDoc
1308 ppr_fam_insts [] = empty
1309 ppr_fam_insts fam_insts =
1310 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1312 ppr_sigs :: [Var] -> SDoc
1314 -- Print type signatures; sort by OccName
1315 = vcat (map ppr_sig (sortLe le_sig ids))
1317 le_sig id1 id2 = getOccName id1 <= getOccName id2
1318 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1320 ppr_rules :: [CoreRule] -> SDoc
1321 ppr_rules [] = empty
1322 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1323 nest 4 (pprRules rs),
1326 ppr_gen_tycons [] = empty
1327 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1328 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]