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 )
90 import {- Kind parts of -} Type
99 import Control.Monad ( unless )
104 %************************************************************************
106 Typecheck and rename a module
108 %************************************************************************
114 -> Bool -- True <=> save renamed syntax
115 -> Located (HsModule RdrName)
116 -> IO (Messages, Maybe TcGblEnv)
118 tcRnModule hsc_env hsc_src save_rn_syntax
119 (L loc (HsModule maybe_mod export_ies
120 import_decls local_decls mod_deprec _
121 module_info maybe_doc))
122 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
124 let { this_pkg = thisPackage (hsc_dflags hsc_env) ;
125 this_mod = case maybe_mod of
126 Nothing -> mAIN -- 'module M where' is omitted
127 Just (L _ mod) -> mkModule this_pkg mod } ;
130 initTc hsc_env hsc_src save_rn_syntax this_mod $
132 do { -- Deal with imports;
133 tcg_env <- tcRnImports hsc_env this_mod import_decls ;
134 setGblEnv tcg_env $ do {
136 -- Load the hi-boot interface for this module, if any
137 -- We do this now so that the boot_names can be passed
138 -- to tcTyAndClassDecls, because the boot_names are
139 -- automatically considered to be loop breakers
141 -- Do this *after* tcRnImports, so that we know whether
142 -- a module that we import imports us; and hence whether to
143 -- look for a hi-boot file
144 boot_iface <- tcHiBootIface hsc_src this_mod ;
146 -- Rename and type check the declarations
147 traceRn (text "rn1a") ;
148 tcg_env <- if isHsBoot hsc_src then
149 tcRnHsBootDecls local_decls
151 tcRnSrcDecls boot_iface local_decls ;
152 setGblEnv tcg_env $ do {
154 -- Report the use of any deprecated things
155 -- We do this *before* processsing the export list so
156 -- that we don't bleat about re-exporting a deprecated
157 -- thing (especially via 'module Foo' export item)
158 -- That is, only uses in the *body* of the module are complained about
159 traceRn (text "rn3") ;
160 failIfErrsM ; -- finishDeprecations crashes sometimes
161 -- as a result of typechecker repairs (e.g. unboundNames)
162 tcg_env <- finishDeprecations (hsc_dflags hsc_env) mod_deprec tcg_env ;
164 -- Process the export list
165 tcg_env <- rnExports (isJust maybe_mod) export_ies tcg_env ;
166 traceRn (text "rn4") ;
168 -- Compare the hi-boot iface (if any) with the real thing
169 -- Must be done after processing the exports
170 tcg_env <- checkHiBootIface tcg_env boot_iface ;
172 -- Rename the Haddock documentation
173 tcg_env <- rnHaddock module_info maybe_doc tcg_env ;
175 -- Report unused names
176 reportUnusedNames export_ies tcg_env ;
178 -- Dump output and return
185 %************************************************************************
189 %************************************************************************
192 tcRnImports :: HscEnv -> Module -> [LImportDecl RdrName] -> TcM TcGblEnv
193 tcRnImports hsc_env this_mod import_decls
194 = do { (rn_imports, rdr_env, imports) <- rnImports import_decls ;
196 ; let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)
197 ; dep_mods = imp_dep_mods imports
199 -- We want instance declarations from all home-package
200 -- modules below this one, including boot modules, except
201 -- ourselves. The 'except ourselves' is so that we don't
202 -- get the instances from this module's hs-boot file
203 ; want_instances :: ModuleName -> Bool
204 ; want_instances mod = mod `elemUFM` dep_mods
205 && mod /= moduleName this_mod
206 ; home_insts = hptInstances hsc_env want_instances
209 -- Record boot-file info in the EPS, so that it's
210 -- visible to loadHiBootInterface in tcRnSrcDecls,
211 -- and any other incrementally-performed imports
212 ; updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
214 -- Update the gbl env
215 ; updGblEnv ( \ gbl ->
216 gbl { tcg_rdr_env = plusOccEnv (tcg_rdr_env gbl) rdr_env,
217 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
218 tcg_rn_imports = fmap (const rn_imports) (tcg_rn_imports gbl),
219 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts
222 ; traceRn (text "rn1" <+> ppr (imp_dep_mods imports))
223 -- Fail if there are any errors so far
224 -- The error printing (if needed) takes advantage
225 -- of the tcg_env we have now set
226 -- ; traceIf (text "rdr_env: " <+> ppr rdr_env)
229 -- Load any orphan-module and family instance-module
230 -- interfaces, so that their rules and instance decls will be
232 ; loadOrphanModules (imp_orphs imports) False
233 ; loadOrphanModules (imp_finsts imports) True
235 -- Check type-familily consistency
236 ; traceRn (text "rn1: checking family instance consistency")
237 ; let { dir_imp_mods = map (\ (mod, _, _) -> mod)
241 ; checkFamInstConsistency (imp_finsts imports) dir_imp_mods ;
247 %************************************************************************
249 Type-checking external-core modules
251 %************************************************************************
254 tcRnExtCore :: HscEnv
256 -> IO (Messages, Maybe ModGuts)
257 -- Nothing => some error occurred
259 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
260 -- The decls are IfaceDecls; all names are original names
261 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
263 initTc hsc_env ExtCoreFile False this_mod $ do {
265 let { ldecls = map noLoc decls } ;
267 -- Deal with the type declarations; first bring their stuff
268 -- into scope, then rname them, then type check them
269 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
271 setGblEnv tcg_env $ do {
273 rn_decls <- rnTyClDecls ldecls ;
276 -- Dump trace of renaming part
277 rnDump (ppr rn_decls) ;
279 -- Typecheck them all together so that
280 -- any mutually recursive types are done right
281 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
282 -- Make the new type env available to stuff slurped from interface files
284 setGblEnv tcg_env $ do {
286 -- Now the core bindings
287 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
291 bndrs = bindersOfBinds core_binds ;
292 my_exports = map (Avail . idName) bndrs ;
293 -- ToDo: export the data types also?
295 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
297 mod_guts = ModGuts { mg_module = this_mod,
299 mg_usages = [], -- ToDo: compute usage
300 mg_dir_imps = [], -- ??
301 mg_deps = noDependencies, -- ??
302 mg_exports = my_exports,
303 mg_types = final_type_env,
304 mg_insts = tcg_insts tcg_env,
305 mg_fam_insts = tcg_fam_insts tcg_env,
306 mg_fam_inst_env = tcg_fam_inst_env tcg_env,
308 mg_binds = core_binds,
311 mg_rdr_env = emptyGlobalRdrEnv,
312 mg_fix_env = emptyFixityEnv,
313 mg_deprecs = NoDeprecs,
314 mg_foreign = NoStubs,
315 mg_hpc_info = noHpcInfo,
316 mg_dbg_sites = noDbgSites
319 tcCoreDump mod_guts ;
324 mkFakeGroup decls -- Rather clumsy; lots of unused fields
325 = emptyRdrGroup { hs_tyclds = decls }
329 %************************************************************************
331 Type-checking the top level of a module
333 %************************************************************************
336 tcRnSrcDecls :: ModDetails -> [LHsDecl RdrName] -> TcM TcGblEnv
337 -- Returns the variables free in the decls
338 -- Reason: solely to report unused imports and bindings
339 tcRnSrcDecls boot_iface decls
340 = do { -- Do all the declarations
341 (tc_envs, lie) <- getLIE $ tc_rn_src_decls boot_iface decls ;
343 -- Finish simplifying class constraints
345 -- tcSimplifyTop deals with constant or ambiguous InstIds.
346 -- How could there be ambiguous ones? They can only arise if a
347 -- top-level decl falls under the monomorphism restriction
348 -- and no subsequent decl instantiates its type.
350 -- We do this after checkMain, so that we use the type info
351 -- thaat checkMain adds
353 -- We do it with both global and local env in scope:
354 -- * the global env exposes the instances to tcSimplifyTop
355 -- * the local env exposes the local Ids to tcSimplifyTop,
356 -- so that we get better error messages (monomorphism restriction)
357 traceTc (text "Tc8") ;
358 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
360 -- Backsubstitution. This must be done last.
361 -- Even tcSimplifyTop may do some unification.
362 traceTc (text "Tc9") ;
363 let { (tcg_env, _) = tc_envs
364 ; TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
365 tcg_rules = rules, tcg_fords = fords } = tcg_env
366 ; all_binds = binds `unionBags` inst_binds } ;
368 (bind_ids, binds', fords', rules') <- zonkTopDecls all_binds rules fords ;
370 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
371 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
374 tcg_fords = fords' } } ;
376 -- Make the new type env available to stuff slurped from interface files
377 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
379 return (tcg_env' { tcg_binds = tcg_binds tcg_env' })
382 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
383 -- Loops around dealing with each top level inter-splice group
384 -- in turn, until it's dealt with the entire module
385 tc_rn_src_decls boot_details ds
386 = do { let { (first_group, group_tail) = findSplice ds } ;
387 -- If ds is [] we get ([], Nothing)
389 -- Deal with decls up to, but not including, the first splice
390 (tcg_env, rn_decls) <- checkNoErrs $ rnTopSrcDecls first_group ;
391 -- checkNoErrs: stop if renaming fails
393 (tcg_env, tcl_env) <- setGblEnv tcg_env $
394 tcTopSrcDecls boot_details rn_decls ;
396 -- If there is no splice, we're nearly done
397 setEnvs (tcg_env, tcl_env) $
399 Nothing -> do { tcg_env <- checkMain ; -- Check for `main'
400 return (tcg_env, tcl_env)
403 -- If there's a splice, we must carry on
404 Just (SpliceDecl splice_expr, rest_ds) -> do {
406 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
409 -- Rename the splice expression, and get its supporting decls
410 (rn_splice_expr, splice_fvs) <- checkNoErrs (rnLExpr splice_expr) ;
411 -- checkNoErrs: don't typecheck if renaming failed
412 rnDump (ppr rn_splice_expr) ;
414 -- Execute the splice
415 spliced_decls <- tcSpliceDecls rn_splice_expr ;
417 -- Glue them on the front of the remaining decls and loop
418 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
419 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
424 %************************************************************************
426 Compiling hs-boot source files, and
427 comparing the hi-boot interface with the real thing
429 %************************************************************************
432 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
433 tcRnHsBootDecls decls
434 = do { let { (first_group, group_tail) = findSplice decls }
437 Just stuff -> spliceInHsBootErr stuff
440 -- Rename the declarations
441 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
442 ; setGblEnv tcg_env $ do {
444 -- Todo: check no foreign decls, no rules, no default decls
446 -- Typecheck type/class decls
447 ; traceTc (text "Tc2")
448 ; let tycl_decls = hs_tyclds rn_group
449 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
450 ; setGblEnv tcg_env $ do {
452 -- Typecheck instance decls
453 ; traceTc (text "Tc3")
454 ; (tcg_env, inst_infos, _deriv_binds)
455 <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group)
456 ; setGblEnv tcg_env $ do {
458 -- Typecheck value declarations
459 ; traceTc (text "Tc5")
460 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
463 -- No simplification or zonking to do
464 ; traceTc (text "Tc7a")
465 ; gbl_env <- getGblEnv
467 -- Make the final type-env
468 -- Include the dfun_ids so that their type sigs
469 -- are written into the interface file
470 ; let { type_env0 = tcg_type_env gbl_env
471 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
472 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
473 ; dfun_ids = map iDFunId inst_infos }
474 ; return (gbl_env { tcg_type_env = type_env2 })
477 spliceInHsBootErr (SpliceDecl (L loc _), _)
478 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
481 Once we've typechecked the body of the module, we want to compare what
482 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
485 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM TcGblEnv
486 -- Compare the hi-boot file for this module (if there is one)
487 -- with the type environment we've just come up with
488 -- In the common case where there is no hi-boot file, the list
489 -- of boot_names is empty.
491 -- The bindings we return give bindings for the dfuns defined in the
492 -- hs-boot file, such as $fbEqT = $fEqT
495 tcg_env@(TcGblEnv { tcg_src = hs_src, tcg_binds = binds,
496 tcg_insts = local_insts, tcg_fam_insts = local_fam_insts,
497 tcg_type_env = local_type_env, tcg_exports = local_exports })
498 (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts,
499 md_types = boot_type_env, md_exports = boot_exports })
500 | isHsBoot hs_src -- Current module is already a hs-boot file!
504 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts $$
507 -- Check the exports of the boot module, one by one
508 ; mapM_ check_export boot_exports
510 -- Check instance declarations
511 ; dfun_binds <- mapM check_inst boot_insts
513 -- Check for no family instances
514 ; unless (null boot_fam_insts) $
515 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
516 "instances in boot files yet...")
517 -- FIXME: Why? The actual comparison is not hard, but what would
518 -- be the equivalent to the dfun bindings returned for class
519 -- instances? We can't easily equate tycons...
521 ; return (tcg_env { tcg_binds = binds `unionBags` unionManyBags dfun_binds }) }
523 check_export boot_avail -- boot_avail is exported by the boot iface
524 | name `elem` dfun_names = return ()
525 | isWiredInName name = return () -- No checking for wired-in names. In particular,
526 -- 'error' is handled by a rather gross hack
527 -- (see comments in GHC.Err.hs-boot)
529 -- Check that the actual module exports the same thing
530 | not (null missing_names)
531 = addErrTc (missingBootThing (head missing_names) "exported by")
533 -- If the boot module does not *define* the thing, we are done
534 -- (it simply re-exports it, and names match, so nothing further to do)
535 | isNothing mb_boot_thing = return ()
537 -- Check that the actual module also defines the thing, and
538 -- then compare the definitions
539 | Just real_thing <- lookupTypeEnv local_type_env name
540 = do { let boot_decl = tyThingToIfaceDecl (fromJust mb_boot_thing)
541 real_decl = tyThingToIfaceDecl real_thing
542 ; checkTc (checkBootDecl boot_decl real_decl)
543 (bootMisMatch real_thing boot_decl real_decl) }
544 -- The easiest way to check compatibility is to convert to
545 -- iface syntax, where we already have good comparison functions
548 = addErrTc (missingBootThing name "defined in")
550 name = availName boot_avail
551 mb_boot_thing = lookupTypeEnv boot_type_env name
552 missing_names = case lookupNameEnv local_export_env name of
554 Just avail -> availNames boot_avail `minusList` availNames avail
556 dfun_names = map getName boot_insts
558 local_export_env :: NameEnv AvailInfo
559 local_export_env = availsToNameEnv local_exports
562 = case [dfun | inst <- local_insts,
563 let dfun = instanceDFunId inst,
564 idType dfun `tcEqType` boot_inst_ty ] of
565 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
566 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
568 boot_dfun = instanceDFunId boot_inst
569 boot_inst_ty = idType boot_dfun
570 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
574 missingBootThing thing what
575 = ppr thing <+> ptext SLIT("is exported by the hs-boot file, but not")
576 <+> text what <+> ptext SLIT("the module")
578 bootMisMatch thing boot_decl real_decl
579 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
580 ptext SLIT("Main module:") <+> ppr real_decl,
581 ptext SLIT("Boot file: ") <+> ppr boot_decl]
585 2 (ptext SLIT("is defined in the hs-boot file, but not in the module itself"))
589 %************************************************************************
591 Type-checking the top level of a module
593 %************************************************************************
595 tcRnGroup takes a bunch of top-level source-code declarations, and
597 * gets supporting declarations from interface files
600 * and augments the TcGblEnv with the results
602 In Template Haskell it may be called repeatedly for each group of
603 declarations. It expects there to be an incoming TcGblEnv in the
604 monad; it augments it and returns the new TcGblEnv.
607 ------------------------------------------------
608 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
610 = do { -- Bring top level binders into scope
611 tcg_env <- importsFromLocalDecls group ;
612 setGblEnv tcg_env $ do {
614 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
616 -- Rename the source decls
617 (tcg_env, rn_decls) <- rnSrcDecls group ;
620 -- save the renamed syntax, if we want it
622 | Just grp <- tcg_rn_decls tcg_env
623 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
627 -- Dump trace of renaming part
628 rnDump (ppr rn_decls) ;
630 return (tcg_env', rn_decls)
633 ------------------------------------------------
634 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
635 tcTopSrcDecls boot_details
636 (HsGroup { hs_tyclds = tycl_decls,
637 hs_instds = inst_decls,
638 hs_derivds = deriv_decls,
639 hs_fords = foreign_decls,
640 hs_defds = default_decls,
641 hs_ruleds = rule_decls,
642 hs_valds = val_binds })
643 = do { -- Type-check the type and class decls, and all imported decls
644 -- The latter come in via tycl_decls
645 traceTc (text "Tc2") ;
647 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
648 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
649 -- an error we'd better stop now, to avoid a cascade
651 -- Make these type and class decls available to stuff slurped from interface files
652 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
655 setGblEnv tcg_env $ do {
656 -- Source-language instances, including derivings,
657 -- and import the supporting declarations
658 traceTc (text "Tc3") ;
659 (tcg_env, inst_infos, deriv_binds)
660 <- tcInstDecls1 tycl_decls inst_decls deriv_decls;
661 setGblEnv tcg_env $ do {
663 -- Foreign import declarations next. No zonking necessary
664 -- here; we can tuck them straight into the global environment.
665 traceTc (text "Tc4") ;
666 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
667 tcExtendGlobalValEnv fi_ids $ do {
669 -- Default declarations
670 traceTc (text "Tc4a") ;
671 default_tys <- tcDefaults default_decls ;
672 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
674 -- Value declarations next
675 -- We also typecheck any extra binds that came out
676 -- of the "deriving" process (deriv_binds)
677 traceTc (text "Tc5") ;
678 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
679 setLclTypeEnv tcl_env $ do {
681 -- Second pass over class and instance declarations,
682 traceTc (text "Tc6") ;
683 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
684 showLIE (text "after instDecls2") ;
687 -- They need to be zonked, so we return them
688 traceTc (text "Tc7") ;
689 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
692 rules <- tcRules rule_decls ;
695 traceTc (text "Tc7a") ;
696 tcg_env <- getGblEnv ;
697 let { all_binds = tc_val_binds `unionBags`
698 inst_binds `unionBags`
701 -- Extend the GblEnv with the (as yet un-zonked)
702 -- bindings, rules, foreign decls
703 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
704 tcg_rules = tcg_rules tcg_env ++ rules,
705 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
706 return (tcg_env', tcl_env)
711 %************************************************************************
715 %************************************************************************
718 checkMain :: TcM TcGblEnv
719 -- If we are in module Main, check that 'main' is defined.
721 = do { ghc_mode <- getGhcMode ;
722 tcg_env <- getGblEnv ;
724 let { main_mod = mainModIs dflags ;
725 main_fn = case mainFunIs dflags of {
726 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
727 Nothing -> main_RDR_Unqual } } ;
729 check_main ghc_mode tcg_env main_mod main_fn
733 check_main ghc_mode tcg_env main_mod main_fn
735 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
739 = addErrCtxt mainCtxt $
740 do { mb_main <- lookupSrcOcc_maybe main_fn
741 -- Check that 'main' is in scope
742 -- It might be imported from another module!
744 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
748 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
749 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
750 -- :Main.main :: IO () = runMainIO main
752 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
755 -- See Note [Root-main Id]
756 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
757 (mkVarOccFS FSLIT("main"))
758 (getSrcLoc main_name)
759 ; root_main_id = Id.mkExportedLocalId root_main_name ty
760 ; main_bind = noLoc (VarBind root_main_id main_expr) }
762 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
764 tcg_dus = tcg_dus tcg_env
765 `plusDU` usesOnly (unitFV main_name)
766 -- Record the use of 'main', so that we don't
767 -- complain about it being defined but not used
771 mod = tcg_mod tcg_env
773 complain_no_main | ghc_mode == Interactive = return ()
774 | otherwise = failWithTc noMainMsg
775 -- In interactive mode, don't worry about the absence of 'main'
776 -- In other modes, fail altogether, so that we don't go on
777 -- and complain a second time when processing the export list.
779 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
780 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
781 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
786 The function that the RTS invokes is always :Main.main, which we call
787 root_main_id. (Because GHC allows the user to have a module not
788 called Main as the main module, we can't rely on the main function
789 being called "Main.main". That's why root_main_id has a fixed module
792 This is unusual: it's a LocalId whose Name has a Module from another
793 module. Tiresomely, we must filter it out again in MkIface, les we
794 get two defns for 'main' in the interface file!
797 %*********************************************************
801 %*********************************************************
805 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
806 setInteractiveContext hsc_env icxt thing_inside
808 -- Initialise the tcg_inst_env with instances
809 -- from all home modules. This mimics the more selective
810 -- call to hptInstances in tcRnModule
811 dfuns = hptInstances hsc_env (\mod -> True)
813 updGblEnv (\env -> env {
814 tcg_rdr_env = ic_rn_gbl_env icxt,
815 tcg_type_env = ic_type_env icxt,
816 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
818 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
820 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
827 -> InteractiveContext
829 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
830 -- The returned [Name] is the same as the input except for
831 -- ExprStmt, in which case the returned [Name] is [itName]
833 -- The returned TypecheckedHsExpr is of type IO [ () ],
834 -- a list of the bound values, coerced to ().
836 tcRnStmt hsc_env ictxt rdr_stmt
837 = initTcPrintErrors hsc_env iNTERACTIVE $
838 setInteractiveContext hsc_env ictxt $ do {
840 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
841 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
842 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
845 -- The real work is done here
846 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
847 zonked_expr <- zonkTopLExpr tc_expr ;
848 zonked_ids <- zonkTopBndrs bound_ids ;
850 -- None of the Ids should be of unboxed type, because we
851 -- cast them all to HValues in the end!
852 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
854 traceTc (text "tcs 1") ;
855 let { -- (a) Make all the bound ids "global" ids, now that
856 -- they're notionally top-level bindings. This is
857 -- important: otherwise when we come to compile an expression
858 -- using these ids later, the byte code generator will consider
859 -- the occurrences to be free rather than global.
861 -- (b) Tidy their types; this is important, because :info may
862 -- ask to look at them, and :info expects the things it looks
863 -- up to have tidy types
864 global_ids = map globaliseAndTidy zonked_ids ;
866 -- Update the interactive context
867 rn_env = ic_rn_local_env ictxt ;
868 type_env = ic_type_env ictxt ;
870 bound_names = map idName global_ids ;
871 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
873 {- ---------------------------------------------
874 At one stage I removed any shadowed bindings from the type_env;
875 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
876 However, with Template Haskell they aren't necessarily inaccessible. Consider this
878 Prelude> let f n = n * 2 :: Int
879 Prelude> fName <- runQ [| f |]
880 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
882 Prelude> let f n = n * 3 :: Int
883 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
884 In the last line we use 'fName', which resolves to the *first* 'f'
885 in scope. If we delete it from the type env, GHCi crashes because
886 it doesn't expect that.
888 Hence this code is commented out
890 shadowed = [ n | name <- bound_names,
891 let rdr_name = mkRdrUnqual (nameOccName name),
892 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
893 filtered_type_env = delListFromNameEnv type_env shadowed ;
894 -------------------------------------------------- -}
896 new_type_env = extendTypeEnvWithIds type_env global_ids ;
897 new_ic = ictxt { ic_rn_local_env = new_rn_env,
898 ic_type_env = new_type_env }
901 dumpOptTcRn Opt_D_dump_tc
902 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
903 text "Typechecked expr" <+> ppr zonked_expr]) ;
905 returnM (new_ic, bound_names, zonked_expr)
908 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
909 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
911 globaliseAndTidy :: Id -> Id
913 -- Give the Id a Global Name, and tidy its type
914 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
916 tidy_type = tidyTopType (idType id)
919 Here is the grand plan, implemented in tcUserStmt
921 What you type The IO [HValue] that hscStmt returns
922 ------------- ------------------------------------
923 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
926 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
929 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
930 [NB: result not printed] bindings: [it]
932 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
933 result showable) bindings: [it]
935 expr (of non-IO type,
936 result not showable) ==> error
940 ---------------------------
941 type PlanResult = ([Id], LHsExpr Id)
942 type Plan = TcM PlanResult
944 runPlans :: [Plan] -> TcM PlanResult
945 -- Try the plans in order. If one fails (by raising an exn), try the next.
946 -- If one succeeds, take it.
947 runPlans [] = panic "runPlans"
949 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
952 mkPlan :: LStmt Name -> TcM PlanResult
953 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
954 = do { uniq <- newUnique -- is treated very specially
955 ; let fresh_it = itName uniq
956 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
957 matches = [mkMatch [] expr emptyLocalBinds]
958 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
959 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
960 (HsVar bindIOName) noSyntaxExpr
961 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
962 (HsVar thenIOName) placeHolderType
965 -- [it <- e; print it] but not if it::()
967 -- [let it = e; print it]
968 ; runPlans [ -- Plan A
969 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
970 ; it_ty <- zonkTcType (idType it_id)
971 ; ifM (isUnitTy it_ty) failM
974 -- Plan B; a naked bind statment
975 tcGhciStmts [bind_stmt],
977 -- Plan C; check that the let-binding is typeable all by itself.
978 -- If not, fail; if so, try to print it.
979 -- The two-step process avoids getting two errors: one from
980 -- the expression itself, and one from the 'print it' part
981 -- This two-step story is very clunky, alas
982 do { checkNoErrs (tcGhciStmts [let_stmt])
983 --- checkNoErrs defeats the error recovery of let-bindings
984 ; tcGhciStmts [let_stmt, print_it] }
987 mkPlan stmt@(L loc (BindStmt {}))
988 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
989 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
990 (HsVar thenIOName) placeHolderType
992 ; print_bind_result <- doptM Opt_PrintBindResult
993 ; let print_plan = do
994 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
995 ; v_ty <- zonkTcType (idType v_id)
996 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
1000 -- [stmt; print v] but not if v::()
1002 ; runPlans ((if print_bind_result then [print_plan] else []) ++
1003 [tcGhciStmts [stmt]])
1007 = tcGhciStmts [stmt]
1009 ---------------------------
1010 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
1012 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
1013 ret_id <- tcLookupId returnIOName ; -- return @ IO
1015 io_ty = mkTyConApp ioTyCon [] ;
1016 ret_ty = mkListTy unitTy ;
1017 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
1018 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
1019 (emptyRefinement, io_ret_ty) ;
1021 names = map unLoc (collectLStmtsBinders stmts) ;
1023 -- mk_return builds the expression
1024 -- returnIO @ [()] [coerce () x, .., coerce () z]
1026 -- Despite the inconvenience of building the type applications etc,
1027 -- this *has* to be done in type-annotated post-typecheck form
1028 -- because we are going to return a list of *polymorphic* values
1029 -- coerced to type (). If we built a *source* stmt
1030 -- return [coerce x, ..., coerce z]
1031 -- then the type checker would instantiate x..z, and we wouldn't
1032 -- get their *polymorphic* values. (And we'd get ambiguity errs
1033 -- if they were overloaded, since they aren't applied to anything.)
1034 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
1035 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1036 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1040 -- OK, we're ready to typecheck the stmts
1041 traceTc (text "tcs 2") ;
1042 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1043 mappM tcLookupId names ;
1044 -- Look up the names right in the middle,
1045 -- where they will all be in scope
1047 -- Simplify the context
1048 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1049 -- checkNoErrs ensures that the plan fails if context redn fails
1051 return (ids, mkHsDictLet const_binds $
1052 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1057 tcRnExpr just finds the type of an expression
1061 -> InteractiveContext
1064 tcRnExpr hsc_env ictxt rdr_expr
1065 = initTcPrintErrors hsc_env iNTERACTIVE $
1066 setInteractiveContext hsc_env ictxt $ do {
1068 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1071 -- Now typecheck the expression;
1072 -- it might have a rank-2 type (e.g. :t runST)
1073 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1074 ((qtvs, dict_insts, _), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1075 tcSimplifyInteractive lie_top ;
1077 let { all_expr_ty = mkForAllTys qtvs $
1078 mkFunTys (map (idType . instToId) dict_insts) $
1080 zonkTcType all_expr_ty
1083 smpl_doc = ptext SLIT("main expression")
1086 tcRnType just finds the kind of a type
1090 -> InteractiveContext
1093 tcRnType hsc_env ictxt rdr_type
1094 = initTcPrintErrors hsc_env iNTERACTIVE $
1095 setInteractiveContext hsc_env ictxt $ do {
1097 rn_type <- rnLHsType doc rdr_type ;
1100 -- Now kind-check the type
1101 (ty', kind) <- kcHsType rn_type ;
1105 doc = ptext SLIT("In GHCi input")
1111 %************************************************************************
1113 More GHCi stuff, to do with browsing and getting info
1115 %************************************************************************
1119 -- ASSUMES that the module is either in the HomePackageTable or is
1120 -- a package module with an interface on disk. If neither of these is
1121 -- true, then the result will be an error indicating the interface
1122 -- could not be found.
1123 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1124 getModuleExports hsc_env mod
1127 checkMods = ic_toplev_scope ic ++ ic_exports ic
1129 initTc hsc_env HsSrcFile False iNTERACTIVE (tcGetModuleExports mod checkMods)
1131 -- Get the export avail info and also load all orphan and family-instance
1132 -- modules. Finally, check that the family instances of all modules in the
1133 -- interactive context are consistent (these modules are in the second
1135 tcGetModuleExports :: Module -> [Module] -> TcM [AvailInfo]
1136 tcGetModuleExports mod directlyImpMods
1137 = do { let doc = ptext SLIT("context for compiling statements")
1138 ; iface <- initIfaceTcRn $ loadSysInterface doc mod
1140 -- Load any orphan-module and family instance-module
1141 -- interfaces, so their instances are visible.
1142 ; loadOrphanModules (dep_orphs (mi_deps iface)) False
1143 ; loadOrphanModules (dep_finsts (mi_deps iface)) True
1145 -- Check that the family instances of all directly loaded
1146 -- modules are consistent.
1147 ; checkFamInstConsistency (dep_finsts (mi_deps iface)) directlyImpMods
1149 ; ifaceExportNames (mi_exports iface)
1152 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1153 tcRnLookupRdrName hsc_env rdr_name
1154 = initTcPrintErrors hsc_env iNTERACTIVE $
1155 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1156 lookup_rdr_name rdr_name
1158 lookup_rdr_name rdr_name = do {
1159 -- If the identifier is a constructor (begins with an
1160 -- upper-case letter), then we need to consider both
1161 -- constructor and type class identifiers.
1162 let { rdr_names = dataTcOccs rdr_name } ;
1164 -- results :: [Either Messages Name]
1165 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1167 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1168 -- The successful lookups will be (Just name)
1169 let { (warns_s, good_names) = unzip [ (msgs, name)
1170 | (msgs, Just name) <- results] ;
1171 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1173 -- Fail if nothing good happened, else add warnings
1174 if null good_names then
1175 -- No lookup succeeded, so
1176 -- pick the first error message and report it
1177 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1178 -- while the other is "X is not in scope",
1179 -- we definitely want the former; but we might pick the latter
1180 do { addMessages (head errs_s) ; failM }
1181 else -- Add deprecation warnings
1182 mapM_ addMessages warns_s ;
1187 tcRnRecoverDataCon :: HscEnv -> a -> IO (Maybe DataCon)
1188 tcRnRecoverDataCon hsc_env a
1189 = initTcPrintErrors hsc_env iNTERACTIVE $
1190 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1191 do name <- recoverDataCon a
1192 tcLookupDataCon name
1194 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1195 tcRnLookupName hsc_env name
1196 = initTcPrintErrors hsc_env iNTERACTIVE $
1197 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1201 tcRnGetInfo :: HscEnv
1203 -> IO (Maybe (TyThing, Fixity, [Instance]))
1205 -- Used to implemnent :info in GHCi
1207 -- Look up a RdrName and return all the TyThings it might be
1208 -- A capitalised RdrName is given to us in the DataName namespace,
1209 -- but we want to treat it as *both* a data constructor
1210 -- *and* as a type or class constructor;
1211 -- hence the call to dataTcOccs, and we return up to two results
1212 tcRnGetInfo hsc_env name
1213 = initTcPrintErrors hsc_env iNTERACTIVE $
1214 let ictxt = hsc_IC hsc_env in
1215 setInteractiveContext hsc_env ictxt $ do
1217 -- Load the interface for all unqualified types and classes
1218 -- That way we will find all the instance declarations
1219 -- (Packages have not orphan modules, and we assume that
1220 -- in the home package all relevant modules are loaded.)
1221 loadUnqualIfaces ictxt
1223 thing <- tcLookupGlobal name
1224 fixity <- lookupFixityRn name
1225 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1226 return (thing, fixity, ispecs)
1228 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1229 -- Filter the instances by the ones whose tycons (or clases resp)
1230 -- are in scope unqualified. Otherwise we list a whole lot too many!
1231 lookupInsts print_unqual (AClass cls)
1232 = do { inst_envs <- tcGetInstEnvs
1234 | ispec <- classInstances inst_envs cls
1235 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1237 lookupInsts print_unqual (ATyCon tc)
1238 = do { eps <- getEps -- Load all instances for all classes that are
1239 -- in the type environment (which are all the ones
1240 -- we've seen in any interface file so far)
1241 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1243 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1244 , let dfun = instanceDFunId ispec
1246 , plausibleDFun print_unqual dfun ] }
1248 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1249 tc_name = tyConName tc
1251 lookupInsts print_unqual other = return []
1253 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1254 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1256 ok name | isBuiltInSyntax name = True
1257 | isExternalName name =
1258 isNothing $ fst print_unqual (nameModule name)
1262 loadUnqualIfaces :: InteractiveContext -> TcM ()
1263 -- Load the home module for everything that is in scope unqualified
1264 -- This is so that we can accurately report the instances for
1266 loadUnqualIfaces ictxt
1268 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1270 unqual_mods = [ nameModule name
1271 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1272 let name = gre_name gre,
1273 not (isInternalName name),
1274 isTcOcc (nameOccName name), -- Types and classes only
1275 unQualOK gre ] -- In scope unqualified
1276 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1280 %************************************************************************
1284 %************************************************************************
1287 rnDump :: SDoc -> TcRn ()
1288 -- Dump, with a banner, if -ddump-rn
1289 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1291 tcDump :: TcGblEnv -> TcRn ()
1293 = do { dflags <- getDOpts ;
1295 -- Dump short output if -ddump-types or -ddump-tc
1296 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1297 (dumpTcRn short_dump) ;
1299 -- Dump bindings if -ddump-tc
1300 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1303 short_dump = pprTcGblEnv env
1304 full_dump = pprLHsBinds (tcg_binds env)
1305 -- NB: foreign x-d's have undefined's in their types;
1306 -- hence can't show the tc_fords
1309 = do { dflags <- getDOpts ;
1310 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1311 (dumpTcRn (pprModGuts mod_guts)) ;
1313 -- Dump bindings if -ddump-tc
1314 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1316 full_dump = pprCoreBindings (mg_binds mod_guts)
1318 -- It's unpleasant having both pprModGuts and pprModDetails here
1319 pprTcGblEnv :: TcGblEnv -> SDoc
1320 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1322 tcg_fam_insts = fam_insts,
1324 tcg_imports = imports })
1325 = vcat [ ppr_types insts type_env
1326 , ppr_tycons fam_insts type_env
1328 , ppr_fam_insts fam_insts
1329 , vcat (map ppr rules)
1330 , ppr_gen_tycons (typeEnvTyCons type_env)
1331 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1332 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1334 pprModGuts :: ModGuts -> SDoc
1335 pprModGuts (ModGuts { mg_types = type_env,
1337 = vcat [ ppr_types [] type_env,
1340 ppr_types :: [Instance] -> TypeEnv -> SDoc
1341 ppr_types insts type_env
1342 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1344 dfun_ids = map instanceDFunId insts
1345 ids = [id | id <- typeEnvIds type_env, want_sig id]
1346 want_sig id | opt_PprStyle_Debug = True
1347 | otherwise = isLocalId id &&
1348 isExternalName (idName id) &&
1349 not (id `elem` dfun_ids)
1350 -- isLocalId ignores data constructors, records selectors etc.
1351 -- The isExternalName ignores local dictionary and method bindings
1352 -- that the type checker has invented. Top-level user-defined things
1353 -- have External names.
1355 ppr_tycons :: [FamInst] -> TypeEnv -> SDoc
1356 ppr_tycons fam_insts type_env
1357 = text "TYPE CONSTRUCTORS" $$ nest 4 (ppr_tydecls tycons)
1359 fi_tycons = map famInstTyCon fam_insts
1360 tycons = [tycon | tycon <- typeEnvTyCons type_env, want_tycon tycon]
1361 want_tycon tycon | opt_PprStyle_Debug = True
1362 | otherwise = not (isImplicitTyCon tycon) &&
1363 isExternalName (tyConName tycon) &&
1364 not (tycon `elem` fi_tycons)
1366 ppr_insts :: [Instance] -> SDoc
1367 ppr_insts [] = empty
1368 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1370 ppr_fam_insts :: [FamInst] -> SDoc
1371 ppr_fam_insts [] = empty
1372 ppr_fam_insts fam_insts =
1373 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1375 ppr_sigs :: [Var] -> SDoc
1377 -- Print type signatures; sort by OccName
1378 = vcat (map ppr_sig (sortLe le_sig ids))
1380 le_sig id1 id2 = getOccName id1 <= getOccName id2
1381 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1383 ppr_tydecls :: [TyCon] -> SDoc
1385 -- Print type constructor info; sort by OccName
1386 = vcat (map ppr_tycon (sortLe le_sig tycons))
1388 le_sig tycon1 tycon2 = getOccName tycon1 <= getOccName tycon2
1390 | isCoercionTyCon tycon = ptext SLIT("coercion") <+> ppr tycon
1391 | otherwise = ppr (tyThingToIfaceDecl (ATyCon tycon))
1393 ppr_rules :: [CoreRule] -> SDoc
1394 ppr_rules [] = empty
1395 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1396 nest 4 (pprRules rs),
1399 ppr_gen_tycons [] = empty
1400 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1401 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]