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
100 import Control.Monad ( unless )
101 import Data.Maybe ( isJust )
106 %************************************************************************
108 Typecheck and rename a module
110 %************************************************************************
116 -> Bool -- True <=> save renamed syntax
117 -> Located (HsModule RdrName)
118 -> IO (Messages, Maybe TcGblEnv)
120 tcRnModule hsc_env hsc_src save_rn_syntax
121 (L loc (HsModule maybe_mod export_ies
122 import_decls local_decls mod_deprec _
123 module_info maybe_doc))
124 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
126 let { this_pkg = thisPackage (hsc_dflags hsc_env) ;
127 this_mod = case maybe_mod of
128 Nothing -> mAIN -- 'module M where' is omitted
129 Just (L _ mod) -> mkModule this_pkg mod } ;
132 initTc hsc_env hsc_src save_rn_syntax this_mod $
134 do { -- Deal with imports;
135 tcg_env <- tcRnImports hsc_env this_mod import_decls ;
136 setGblEnv tcg_env $ do {
138 -- Load the hi-boot interface for this module, if any
139 -- We do this now so that the boot_names can be passed
140 -- to tcTyAndClassDecls, because the boot_names are
141 -- automatically considered to be loop breakers
143 -- Do this *after* tcRnImports, so that we know whether
144 -- a module that we import imports us; and hence whether to
145 -- look for a hi-boot file
146 boot_iface <- tcHiBootIface hsc_src this_mod ;
148 -- Rename and type check the declarations
149 traceRn (text "rn1a") ;
150 tcg_env <- if isHsBoot hsc_src then
151 tcRnHsBootDecls local_decls
153 tcRnSrcDecls boot_iface local_decls ;
154 setGblEnv tcg_env $ do {
156 -- Report the use of any deprecated things
157 -- We do this *before* processsing the export list so
158 -- that we don't bleat about re-exporting a deprecated
159 -- thing (especially via 'module Foo' export item)
160 -- That is, only uses in the *body* of the module are complained about
161 traceRn (text "rn3") ;
162 failIfErrsM ; -- finishDeprecations crashes sometimes
163 -- as a result of typechecker repairs (e.g. unboundNames)
164 tcg_env <- finishDeprecations (hsc_dflags hsc_env) mod_deprec tcg_env ;
166 -- Process the export list
167 tcg_env <- rnExports (isJust maybe_mod) export_ies tcg_env ;
168 traceRn (text "rn4") ;
170 -- Compare the hi-boot iface (if any) with the real thing
171 -- Must be done after processing the exports
172 tcg_env <- checkHiBootIface tcg_env boot_iface ;
174 -- Rename the Haddock documentation
175 tcg_env <- rnHaddock module_info maybe_doc tcg_env ;
177 -- Report unused names
178 reportUnusedNames export_ies tcg_env ;
180 -- Dump output and return
187 %************************************************************************
191 %************************************************************************
194 tcRnImports :: HscEnv -> Module -> [LImportDecl RdrName] -> TcM TcGblEnv
195 tcRnImports hsc_env this_mod import_decls
196 = do { (rn_imports, rdr_env, imports) <- rnImports import_decls ;
198 ; let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)
199 ; dep_mods = imp_dep_mods imports
201 -- We want instance declarations from all home-package
202 -- modules below this one, including boot modules, except
203 -- ourselves. The 'except ourselves' is so that we don't
204 -- get the instances from this module's hs-boot file
205 ; want_instances :: ModuleName -> Bool
206 ; want_instances mod = mod `elemUFM` dep_mods
207 && mod /= moduleName this_mod
208 ; home_insts = hptInstances hsc_env want_instances
211 -- Record boot-file info in the EPS, so that it's
212 -- visible to loadHiBootInterface in tcRnSrcDecls,
213 -- and any other incrementally-performed imports
214 ; updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
216 -- Update the gbl env
217 ; updGblEnv ( \ gbl ->
218 gbl { tcg_rdr_env = plusOccEnv (tcg_rdr_env gbl) rdr_env,
219 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
220 tcg_rn_imports = fmap (const rn_imports) (tcg_rn_imports gbl),
221 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts
224 ; traceRn (text "rn1" <+> ppr (imp_dep_mods imports))
225 -- Fail if there are any errors so far
226 -- The error printing (if needed) takes advantage
227 -- of the tcg_env we have now set
228 -- ; traceIf (text "rdr_env: " <+> ppr rdr_env)
231 -- Load any orphan-module and family instance-module
232 -- interfaces, so that their rules and instance decls will be
234 ; loadOrphanModules (imp_orphs imports) False
235 ; loadOrphanModules (imp_finsts imports) True
237 -- Check type-familily consistency
238 ; traceRn (text "rn1: checking family instance consistency")
239 ; let { dir_imp_mods = map (\ (mod, _, _) -> mod)
243 ; checkFamInstConsistency (imp_finsts imports) dir_imp_mods ;
249 %************************************************************************
251 Type-checking external-core modules
253 %************************************************************************
256 tcRnExtCore :: HscEnv
258 -> IO (Messages, Maybe ModGuts)
259 -- Nothing => some error occurred
261 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
262 -- The decls are IfaceDecls; all names are original names
263 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
265 initTc hsc_env ExtCoreFile False this_mod $ do {
267 let { ldecls = map noLoc decls } ;
269 -- Deal with the type declarations; first bring their stuff
270 -- into scope, then rname them, then type check them
271 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
273 setGblEnv tcg_env $ do {
275 rn_decls <- rnTyClDecls ldecls ;
278 -- Dump trace of renaming part
279 rnDump (ppr rn_decls) ;
281 -- Typecheck them all together so that
282 -- any mutually recursive types are done right
283 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
284 -- Make the new type env available to stuff slurped from interface files
286 setGblEnv tcg_env $ do {
288 -- Now the core bindings
289 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
293 bndrs = bindersOfBinds core_binds ;
294 my_exports = map (Avail . idName) bndrs ;
295 -- ToDo: export the data types also?
297 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
299 mod_guts = ModGuts { mg_module = this_mod,
301 mg_usages = [], -- ToDo: compute usage
302 mg_dir_imps = [], -- ??
303 mg_deps = noDependencies, -- ??
304 mg_exports = my_exports,
305 mg_types = final_type_env,
306 mg_insts = tcg_insts tcg_env,
307 mg_fam_insts = tcg_fam_insts tcg_env,
308 mg_fam_inst_env = tcg_fam_inst_env tcg_env,
310 mg_binds = core_binds,
313 mg_rdr_env = emptyGlobalRdrEnv,
314 mg_fix_env = emptyFixityEnv,
315 mg_deprecs = NoDeprecs,
316 mg_foreign = NoStubs,
317 mg_hpc_info = noHpcInfo,
318 mg_dbg_sites = noDbgSites
321 tcCoreDump mod_guts ;
326 mkFakeGroup decls -- Rather clumsy; lots of unused fields
327 = emptyRdrGroup { hs_tyclds = decls }
331 %************************************************************************
333 Type-checking the top level of a module
335 %************************************************************************
338 tcRnSrcDecls :: ModDetails -> [LHsDecl RdrName] -> TcM TcGblEnv
339 -- Returns the variables free in the decls
340 -- Reason: solely to report unused imports and bindings
341 tcRnSrcDecls boot_iface decls
342 = do { -- Do all the declarations
343 (tc_envs, lie) <- getLIE $ tc_rn_src_decls boot_iface decls ;
345 -- Finish simplifying class constraints
347 -- tcSimplifyTop deals with constant or ambiguous InstIds.
348 -- How could there be ambiguous ones? They can only arise if a
349 -- top-level decl falls under the monomorphism restriction
350 -- and no subsequent decl instantiates its type.
352 -- We do this after checkMain, so that we use the type info
353 -- thaat checkMain adds
355 -- We do it with both global and local env in scope:
356 -- * the global env exposes the instances to tcSimplifyTop
357 -- * the local env exposes the local Ids to tcSimplifyTop,
358 -- so that we get better error messages (monomorphism restriction)
359 traceTc (text "Tc8") ;
360 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
362 -- Backsubstitution. This must be done last.
363 -- Even tcSimplifyTop may do some unification.
364 traceTc (text "Tc9") ;
365 let { (tcg_env, _) = tc_envs
366 ; TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
367 tcg_rules = rules, tcg_fords = fords } = tcg_env
368 ; all_binds = binds `unionBags` inst_binds } ;
370 (bind_ids, binds', fords', rules') <- zonkTopDecls all_binds rules fords ;
372 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
373 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
376 tcg_fords = fords' } } ;
378 -- Make the new type env available to stuff slurped from interface files
379 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
381 return (tcg_env' { tcg_binds = tcg_binds tcg_env' })
384 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
385 -- Loops around dealing with each top level inter-splice group
386 -- in turn, until it's dealt with the entire module
387 tc_rn_src_decls boot_details ds
388 = do { let { (first_group, group_tail) = findSplice ds } ;
389 -- If ds is [] we get ([], Nothing)
391 -- Deal with decls up to, but not including, the first splice
392 (tcg_env, rn_decls) <- checkNoErrs $ rnTopSrcDecls first_group ;
393 -- checkNoErrs: stop if renaming fails
395 (tcg_env, tcl_env) <- setGblEnv tcg_env $
396 tcTopSrcDecls boot_details rn_decls ;
398 -- If there is no splice, we're nearly done
399 setEnvs (tcg_env, tcl_env) $
401 Nothing -> do { tcg_env <- checkMain ; -- Check for `main'
402 return (tcg_env, tcl_env)
405 -- If there's a splice, we must carry on
406 Just (SpliceDecl splice_expr, rest_ds) -> do {
408 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
411 -- Rename the splice expression, and get its supporting decls
412 (rn_splice_expr, splice_fvs) <- checkNoErrs (rnLExpr splice_expr) ;
413 -- checkNoErrs: don't typecheck if renaming failed
414 rnDump (ppr rn_splice_expr) ;
416 -- Execute the splice
417 spliced_decls <- tcSpliceDecls rn_splice_expr ;
419 -- Glue them on the front of the remaining decls and loop
420 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
421 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
426 %************************************************************************
428 Compiling hs-boot source files, and
429 comparing the hi-boot interface with the real thing
431 %************************************************************************
434 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
435 tcRnHsBootDecls decls
436 = do { let { (first_group, group_tail) = findSplice decls }
439 Just stuff -> spliceInHsBootErr stuff
442 -- Rename the declarations
443 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
444 ; setGblEnv tcg_env $ do {
446 -- Todo: check no foreign decls, no rules, no default decls
448 -- Typecheck type/class decls
449 ; traceTc (text "Tc2")
450 ; let tycl_decls = hs_tyclds rn_group
451 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
452 ; setGblEnv tcg_env $ do {
454 -- Typecheck instance decls
455 ; traceTc (text "Tc3")
456 ; (tcg_env, inst_infos, _deriv_binds)
457 <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group)
458 ; setGblEnv tcg_env $ do {
460 -- Typecheck value declarations
461 ; traceTc (text "Tc5")
462 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
465 -- No simplification or zonking to do
466 ; traceTc (text "Tc7a")
467 ; gbl_env <- getGblEnv
469 -- Make the final type-env
470 -- Include the dfun_ids so that their type sigs
471 -- are written into the interface file
472 ; let { type_env0 = tcg_type_env gbl_env
473 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
474 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
475 ; dfun_ids = map iDFunId inst_infos }
476 ; return (gbl_env { tcg_type_env = type_env2 })
479 spliceInHsBootErr (SpliceDecl (L loc _), _)
480 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
483 Once we've typechecked the body of the module, we want to compare what
484 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
487 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM TcGblEnv
488 -- Compare the hi-boot file for this module (if there is one)
489 -- with the type environment we've just come up with
490 -- In the common case where there is no hi-boot file, the list
491 -- of boot_names is empty.
493 -- The bindings we return give bindings for the dfuns defined in the
494 -- hs-boot file, such as $fbEqT = $fEqT
497 tcg_env@(TcGblEnv { tcg_src = hs_src, tcg_binds = binds,
498 tcg_insts = local_insts, tcg_fam_insts = local_fam_insts,
499 tcg_type_env = local_type_env, tcg_exports = local_exports })
500 (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts,
501 md_types = boot_type_env, md_exports = boot_exports })
502 | isHsBoot hs_src -- Current module is already a hs-boot file!
506 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts $$
509 -- Check the exports of the boot module, one by one
510 ; mapM_ check_export boot_exports
512 -- Check instance declarations
513 ; dfun_binds <- mapM check_inst boot_insts
515 -- Check for no family instances
516 ; unless (null boot_fam_insts) $
517 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
518 "instances in boot files yet...")
519 -- FIXME: Why? The actual comparison is not hard, but what would
520 -- be the equivalent to the dfun bindings returned for class
521 -- instances? We can't easily equate tycons...
523 ; return (tcg_env { tcg_binds = binds `unionBags` unionManyBags dfun_binds }) }
525 check_export boot_avail -- boot_avail is exported by the boot iface
526 | name `elem` dfun_names = return ()
527 | isWiredInName name = return () -- No checking for wired-in names. In particular,
528 -- 'error' is handled by a rather gross hack
529 -- (see comments in GHC.Err.hs-boot)
531 -- Check that the actual module exports the same thing
532 | not (null missing_names)
533 = addErrTc (missingBootThing (head missing_names) "exported by")
535 -- If the boot module does not *define* the thing, we are done
536 -- (it simply re-exports it, and names match, so nothing further to do)
537 | isNothing mb_boot_thing = return ()
539 -- Check that the actual module also defines the thing, and
540 -- then compare the definitions
541 | Just real_thing <- lookupTypeEnv local_type_env name
542 = do { let boot_decl = tyThingToIfaceDecl (fromJust mb_boot_thing)
543 real_decl = tyThingToIfaceDecl real_thing
544 ; checkTc (checkBootDecl boot_decl real_decl)
545 (bootMisMatch real_thing boot_decl real_decl) }
546 -- The easiest way to check compatibility is to convert to
547 -- iface syntax, where we already have good comparison functions
550 = addErrTc (missingBootThing name "defined in")
552 name = availName boot_avail
553 mb_boot_thing = lookupTypeEnv boot_type_env name
554 missing_names = case lookupNameEnv local_export_env name of
556 Just avail -> availNames boot_avail `minusList` availNames avail
558 dfun_names = map getName boot_insts
560 local_export_env :: NameEnv AvailInfo
561 local_export_env = availsToNameEnv local_exports
564 = case [dfun | inst <- local_insts,
565 let dfun = instanceDFunId inst,
566 idType dfun `tcEqType` boot_inst_ty ] of
567 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
568 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
570 boot_dfun = instanceDFunId boot_inst
571 boot_inst_ty = idType boot_dfun
572 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
576 missingBootThing thing what
577 = ppr thing <+> ptext SLIT("is exported by the hs-boot file, but not")
578 <+> text what <+> ptext SLIT("the module")
580 bootMisMatch thing boot_decl real_decl
581 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
582 ptext SLIT("Main module:") <+> ppr real_decl,
583 ptext SLIT("Boot file: ") <+> ppr boot_decl]
587 2 (ptext SLIT("is defined in the hs-boot file, but not in the module itself"))
591 %************************************************************************
593 Type-checking the top level of a module
595 %************************************************************************
597 tcRnGroup takes a bunch of top-level source-code declarations, and
599 * gets supporting declarations from interface files
602 * and augments the TcGblEnv with the results
604 In Template Haskell it may be called repeatedly for each group of
605 declarations. It expects there to be an incoming TcGblEnv in the
606 monad; it augments it and returns the new TcGblEnv.
609 ------------------------------------------------
610 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
612 = do { -- Bring top level binders into scope
613 tcg_env <- importsFromLocalDecls group ;
614 setGblEnv tcg_env $ do {
616 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
618 -- Rename the source decls
619 (tcg_env, rn_decls) <- rnSrcDecls group ;
622 -- save the renamed syntax, if we want it
624 | Just grp <- tcg_rn_decls tcg_env
625 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
629 -- Dump trace of renaming part
630 rnDump (ppr rn_decls) ;
632 return (tcg_env', rn_decls)
635 ------------------------------------------------
636 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
637 tcTopSrcDecls boot_details
638 (HsGroup { hs_tyclds = tycl_decls,
639 hs_instds = inst_decls,
640 hs_derivds = deriv_decls,
641 hs_fords = foreign_decls,
642 hs_defds = default_decls,
643 hs_ruleds = rule_decls,
644 hs_valds = val_binds })
645 = do { -- Type-check the type and class decls, and all imported decls
646 -- The latter come in via tycl_decls
647 traceTc (text "Tc2") ;
649 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
650 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
651 -- an error we'd better stop now, to avoid a cascade
653 -- Make these type and class decls available to stuff slurped from interface files
654 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
657 setGblEnv tcg_env $ do {
658 -- Source-language instances, including derivings,
659 -- and import the supporting declarations
660 traceTc (text "Tc3") ;
661 (tcg_env, inst_infos, deriv_binds)
662 <- tcInstDecls1 tycl_decls inst_decls deriv_decls;
663 setGblEnv tcg_env $ do {
665 -- Foreign import declarations next. No zonking necessary
666 -- here; we can tuck them straight into the global environment.
667 traceTc (text "Tc4") ;
668 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
669 tcExtendGlobalValEnv fi_ids $ do {
671 -- Default declarations
672 traceTc (text "Tc4a") ;
673 default_tys <- tcDefaults default_decls ;
674 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
676 -- Value declarations next
677 -- We also typecheck any extra binds that came out
678 -- of the "deriving" process (deriv_binds)
679 traceTc (text "Tc5") ;
680 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
681 setLclTypeEnv tcl_env $ do {
683 -- Second pass over class and instance declarations,
684 traceTc (text "Tc6") ;
685 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
686 showLIE (text "after instDecls2") ;
689 -- They need to be zonked, so we return them
690 traceTc (text "Tc7") ;
691 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
694 rules <- tcRules rule_decls ;
697 traceTc (text "Tc7a") ;
698 tcg_env <- getGblEnv ;
699 let { all_binds = tc_val_binds `unionBags`
700 inst_binds `unionBags`
703 -- Extend the GblEnv with the (as yet un-zonked)
704 -- bindings, rules, foreign decls
705 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
706 tcg_rules = tcg_rules tcg_env ++ rules,
707 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
708 return (tcg_env', tcl_env)
713 %************************************************************************
717 %************************************************************************
720 checkMain :: TcM TcGblEnv
721 -- If we are in module Main, check that 'main' is defined.
723 = do { ghc_mode <- getGhcMode ;
724 tcg_env <- getGblEnv ;
726 let { main_mod = mainModIs dflags ;
727 main_fn = case mainFunIs dflags of {
728 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
729 Nothing -> main_RDR_Unqual } } ;
731 check_main ghc_mode tcg_env main_mod main_fn
735 check_main ghc_mode tcg_env main_mod main_fn
737 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
741 = addErrCtxt mainCtxt $
742 do { mb_main <- lookupSrcOcc_maybe main_fn
743 -- Check that 'main' is in scope
744 -- It might be imported from another module!
746 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
750 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
751 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
752 -- :Main.main :: IO () = runMainIO main
754 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
757 -- See Note [Root-main Id]
758 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
759 (mkVarOccFS FSLIT("main"))
760 (getSrcLoc main_name)
761 ; root_main_id = Id.mkExportedLocalId root_main_name ty
762 ; main_bind = noLoc (VarBind root_main_id main_expr) }
764 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
766 tcg_dus = tcg_dus tcg_env
767 `plusDU` usesOnly (unitFV main_name)
768 -- Record the use of 'main', so that we don't
769 -- complain about it being defined but not used
773 mod = tcg_mod tcg_env
775 complain_no_main | ghc_mode == Interactive = return ()
776 | otherwise = failWithTc noMainMsg
777 -- In interactive mode, don't worry about the absence of 'main'
778 -- In other modes, fail altogether, so that we don't go on
779 -- and complain a second time when processing the export list.
781 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
782 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
783 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
788 The function that the RTS invokes is always :Main.main, which we call
789 root_main_id. (Because GHC allows the user to have a module not
790 called Main as the main module, we can't rely on the main function
791 being called "Main.main". That's why root_main_id has a fixed module
794 This is unusual: it's a LocalId whose Name has a Module from another
795 module. Tiresomely, we must filter it out again in MkIface, les we
796 get two defns for 'main' in the interface file!
799 %*********************************************************
803 %*********************************************************
807 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
808 setInteractiveContext hsc_env icxt thing_inside
810 -- Initialise the tcg_inst_env with instances
811 -- from all home modules. This mimics the more selective
812 -- call to hptInstances in tcRnModule
813 dfuns = hptInstances hsc_env (\mod -> True)
815 updGblEnv (\env -> env {
816 tcg_rdr_env = ic_rn_gbl_env icxt,
817 tcg_type_env = ic_type_env icxt,
818 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
820 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
822 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
829 -> InteractiveContext
831 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
832 -- The returned [Name] is the same as the input except for
833 -- ExprStmt, in which case the returned [Name] is [itName]
835 -- The returned TypecheckedHsExpr is of type IO [ () ],
836 -- a list of the bound values, coerced to ().
838 tcRnStmt hsc_env ictxt rdr_stmt
839 = initTcPrintErrors hsc_env iNTERACTIVE $
840 setInteractiveContext hsc_env ictxt $ do {
842 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
843 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
844 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
847 -- The real work is done here
848 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
849 zonked_expr <- zonkTopLExpr tc_expr ;
850 zonked_ids <- zonkTopBndrs bound_ids ;
852 -- None of the Ids should be of unboxed type, because we
853 -- cast them all to HValues in the end!
854 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
856 traceTc (text "tcs 1") ;
857 let { -- (a) Make all the bound ids "global" ids, now that
858 -- they're notionally top-level bindings. This is
859 -- important: otherwise when we come to compile an expression
860 -- using these ids later, the byte code generator will consider
861 -- the occurrences to be free rather than global.
863 -- (b) Tidy their types; this is important, because :info may
864 -- ask to look at them, and :info expects the things it looks
865 -- up to have tidy types
866 global_ids = map globaliseAndTidy zonked_ids ;
868 -- Update the interactive context
869 rn_env = ic_rn_local_env ictxt ;
870 type_env = ic_type_env ictxt ;
872 bound_names = map idName global_ids ;
873 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
875 {- ---------------------------------------------
876 At one stage I removed any shadowed bindings from the type_env;
877 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
878 However, with Template Haskell they aren't necessarily inaccessible. Consider this
880 Prelude> let f n = n * 2 :: Int
881 Prelude> fName <- runQ [| f |]
882 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
884 Prelude> let f n = n * 3 :: Int
885 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
886 In the last line we use 'fName', which resolves to the *first* 'f'
887 in scope. If we delete it from the type env, GHCi crashes because
888 it doesn't expect that.
890 Hence this code is commented out
892 shadowed = [ n | name <- bound_names,
893 let rdr_name = mkRdrUnqual (nameOccName name),
894 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
895 filtered_type_env = delListFromNameEnv type_env shadowed ;
896 -------------------------------------------------- -}
898 new_type_env = extendTypeEnvWithIds type_env global_ids ;
899 new_ic = ictxt { ic_rn_local_env = new_rn_env,
900 ic_type_env = new_type_env }
903 dumpOptTcRn Opt_D_dump_tc
904 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
905 text "Typechecked expr" <+> ppr zonked_expr]) ;
907 returnM (new_ic, bound_names, zonked_expr)
910 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
911 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
913 globaliseAndTidy :: Id -> Id
915 -- Give the Id a Global Name, and tidy its type
916 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
918 tidy_type = tidyTopType (idType id)
921 Here is the grand plan, implemented in tcUserStmt
923 What you type The IO [HValue] that hscStmt returns
924 ------------- ------------------------------------
925 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
928 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
931 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
932 [NB: result not printed] bindings: [it]
934 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
935 result showable) bindings: [it]
937 expr (of non-IO type,
938 result not showable) ==> error
942 ---------------------------
943 type PlanResult = ([Id], LHsExpr Id)
944 type Plan = TcM PlanResult
946 runPlans :: [Plan] -> TcM PlanResult
947 -- Try the plans in order. If one fails (by raising an exn), try the next.
948 -- If one succeeds, take it.
949 runPlans [] = panic "runPlans"
951 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
954 mkPlan :: LStmt Name -> TcM PlanResult
955 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
956 = do { uniq <- newUnique -- is treated very specially
957 ; let fresh_it = itName uniq
958 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
959 matches = [mkMatch [] expr emptyLocalBinds]
960 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
961 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
962 (HsVar bindIOName) noSyntaxExpr
963 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
964 (HsVar thenIOName) placeHolderType
967 -- [it <- e; print it] but not if it::()
969 -- [let it = e; print it]
970 ; runPlans [ -- Plan A
971 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
972 ; it_ty <- zonkTcType (idType it_id)
973 ; ifM (isUnitTy it_ty) failM
976 -- Plan B; a naked bind statment
977 tcGhciStmts [bind_stmt],
979 -- Plan C; check that the let-binding is typeable all by itself.
980 -- If not, fail; if so, try to print it.
981 -- The two-step process avoids getting two errors: one from
982 -- the expression itself, and one from the 'print it' part
983 -- This two-step story is very clunky, alas
984 do { checkNoErrs (tcGhciStmts [let_stmt])
985 --- checkNoErrs defeats the error recovery of let-bindings
986 ; tcGhciStmts [let_stmt, print_it] }
989 mkPlan stmt@(L loc (BindStmt {}))
990 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
991 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
992 (HsVar thenIOName) placeHolderType
994 ; print_bind_result <- doptM Opt_PrintBindResult
995 ; let print_plan = do
996 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
997 ; v_ty <- zonkTcType (idType v_id)
998 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
1002 -- [stmt; print v] but not if v::()
1004 ; runPlans ((if print_bind_result then [print_plan] else []) ++
1005 [tcGhciStmts [stmt]])
1009 = tcGhciStmts [stmt]
1011 ---------------------------
1012 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
1014 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
1015 ret_id <- tcLookupId returnIOName ; -- return @ IO
1017 io_ty = mkTyConApp ioTyCon [] ;
1018 ret_ty = mkListTy unitTy ;
1019 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
1020 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
1021 (emptyRefinement, io_ret_ty) ;
1023 names = map unLoc (collectLStmtsBinders stmts) ;
1025 -- mk_return builds the expression
1026 -- returnIO @ [()] [coerce () x, .., coerce () z]
1028 -- Despite the inconvenience of building the type applications etc,
1029 -- this *has* to be done in type-annotated post-typecheck form
1030 -- because we are going to return a list of *polymorphic* values
1031 -- coerced to type (). If we built a *source* stmt
1032 -- return [coerce x, ..., coerce z]
1033 -- then the type checker would instantiate x..z, and we wouldn't
1034 -- get their *polymorphic* values. (And we'd get ambiguity errs
1035 -- if they were overloaded, since they aren't applied to anything.)
1036 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
1037 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1038 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1042 -- OK, we're ready to typecheck the stmts
1043 traceTc (text "tcs 2") ;
1044 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1045 mappM tcLookupId names ;
1046 -- Look up the names right in the middle,
1047 -- where they will all be in scope
1049 -- Simplify the context
1050 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1051 -- checkNoErrs ensures that the plan fails if context redn fails
1053 return (ids, mkHsDictLet const_binds $
1054 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1059 tcRnExpr just finds the type of an expression
1063 -> InteractiveContext
1066 tcRnExpr hsc_env ictxt rdr_expr
1067 = initTcPrintErrors hsc_env iNTERACTIVE $
1068 setInteractiveContext hsc_env ictxt $ do {
1070 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1073 -- Now typecheck the expression;
1074 -- it might have a rank-2 type (e.g. :t runST)
1075 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1076 ((qtvs, dict_insts, _), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1077 tcSimplifyInteractive lie_top ;
1079 let { all_expr_ty = mkForAllTys qtvs $
1080 mkFunTys (map (idType . instToId) dict_insts) $
1082 zonkTcType all_expr_ty
1085 smpl_doc = ptext SLIT("main expression")
1088 tcRnType just finds the kind of a type
1092 -> InteractiveContext
1095 tcRnType hsc_env ictxt rdr_type
1096 = initTcPrintErrors hsc_env iNTERACTIVE $
1097 setInteractiveContext hsc_env ictxt $ do {
1099 rn_type <- rnLHsType doc rdr_type ;
1102 -- Now kind-check the type
1103 (ty', kind) <- kcHsType rn_type ;
1107 doc = ptext SLIT("In GHCi input")
1113 %************************************************************************
1115 More GHCi stuff, to do with browsing and getting info
1117 %************************************************************************
1121 -- ASSUMES that the module is either in the HomePackageTable or is
1122 -- a package module with an interface on disk. If neither of these is
1123 -- true, then the result will be an error indicating the interface
1124 -- could not be found.
1125 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1126 getModuleExports hsc_env mod
1129 checkMods = ic_toplev_scope ic ++ ic_exports ic
1131 initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod checkMods)
1133 -- Get the export avail info and also load all orphan and family-instance
1134 -- modules. Finally, check that the family instances of all modules in the
1135 -- interactive context are consistent (these modules are in the second
1137 tcGetModuleExports :: Module -> [Module] -> TcM [AvailInfo]
1138 tcGetModuleExports mod directlyImpMods
1139 = do { let doc = ptext SLIT("context for compiling statements")
1140 ; iface <- initIfaceTcRn $ loadSysInterface doc mod
1142 -- Load any orphan-module and family instance-module
1143 -- interfaces, so their instances are visible.
1144 ; loadOrphanModules (dep_orphs (mi_deps iface)) False
1145 ; loadOrphanModules (dep_finsts (mi_deps iface)) True
1147 -- Check that the family instances of all directly loaded
1148 -- modules are consistent.
1149 ; checkFamInstConsistency (dep_finsts (mi_deps iface)) directlyImpMods
1151 ; ifaceExportNames (mi_exports iface)
1154 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1155 tcRnLookupRdrName hsc_env rdr_name
1156 = initTcPrintErrors hsc_env iNTERACTIVE $
1157 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1158 lookup_rdr_name rdr_name
1160 lookup_rdr_name rdr_name = do {
1161 -- If the identifier is a constructor (begins with an
1162 -- upper-case letter), then we need to consider both
1163 -- constructor and type class identifiers.
1164 let { rdr_names = dataTcOccs rdr_name } ;
1166 -- results :: [Either Messages Name]
1167 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1169 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1170 -- The successful lookups will be (Just name)
1171 let { (warns_s, good_names) = unzip [ (msgs, name)
1172 | (msgs, Just name) <- results] ;
1173 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1175 -- Fail if nothing good happened, else add warnings
1176 if null good_names then
1177 -- No lookup succeeded, so
1178 -- pick the first error message and report it
1179 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1180 -- while the other is "X is not in scope",
1181 -- we definitely want the former; but we might pick the latter
1182 do { addMessages (head errs_s) ; failM }
1183 else -- Add deprecation warnings
1184 mapM_ addMessages warns_s ;
1189 tcRnRecoverDataCon :: HscEnv -> a -> IO (Maybe DataCon)
1190 tcRnRecoverDataCon hsc_env a
1191 = initTcPrintErrors hsc_env iNTERACTIVE $
1192 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1193 do name <- recoverDataCon a
1194 tcLookupDataCon name
1196 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1197 tcRnLookupName hsc_env name
1198 = initTcPrintErrors hsc_env iNTERACTIVE $
1199 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1203 tcRnGetInfo :: HscEnv
1205 -> IO (Maybe (TyThing, Fixity, [Instance]))
1207 -- Used to implemnent :info in GHCi
1209 -- Look up a RdrName and return all the TyThings it might be
1210 -- A capitalised RdrName is given to us in the DataName namespace,
1211 -- but we want to treat it as *both* a data constructor
1212 -- *and* as a type or class constructor;
1213 -- hence the call to dataTcOccs, and we return up to two results
1214 tcRnGetInfo hsc_env name
1215 = initTcPrintErrors hsc_env iNTERACTIVE $
1216 let ictxt = hsc_IC hsc_env in
1217 setInteractiveContext hsc_env ictxt $ do
1219 -- Load the interface for all unqualified types and classes
1220 -- That way we will find all the instance declarations
1221 -- (Packages have not orphan modules, and we assume that
1222 -- in the home package all relevant modules are loaded.)
1223 loadUnqualIfaces ictxt
1225 thing <- tcLookupGlobal name
1226 fixity <- lookupFixityRn name
1227 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1228 return (thing, fixity, ispecs)
1230 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1231 -- Filter the instances by the ones whose tycons (or clases resp)
1232 -- are in scope unqualified. Otherwise we list a whole lot too many!
1233 lookupInsts print_unqual (AClass cls)
1234 = do { inst_envs <- tcGetInstEnvs
1236 | ispec <- classInstances inst_envs cls
1237 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1239 lookupInsts print_unqual (ATyCon tc)
1240 = do { eps <- getEps -- Load all instances for all classes that are
1241 -- in the type environment (which are all the ones
1242 -- we've seen in any interface file so far)
1243 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1245 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1246 , let dfun = instanceDFunId ispec
1248 , plausibleDFun print_unqual dfun ] }
1250 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1251 tc_name = tyConName tc
1253 lookupInsts print_unqual other = return []
1255 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1256 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1258 ok name | isBuiltInSyntax name = True
1259 | isExternalName name =
1260 isNothing $ fst print_unqual (nameModule name)
1264 loadUnqualIfaces :: InteractiveContext -> TcM ()
1265 -- Load the home module for everything that is in scope unqualified
1266 -- This is so that we can accurately report the instances for
1268 loadUnqualIfaces ictxt
1270 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1272 unqual_mods = [ nameModule name
1273 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1274 let name = gre_name gre,
1275 not (isInternalName name),
1276 isTcOcc (nameOccName name), -- Types and classes only
1277 unQualOK gre ] -- In scope unqualified
1278 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1282 %************************************************************************
1286 %************************************************************************
1289 rnDump :: SDoc -> TcRn ()
1290 -- Dump, with a banner, if -ddump-rn
1291 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1293 tcDump :: TcGblEnv -> TcRn ()
1295 = do { dflags <- getDOpts ;
1297 -- Dump short output if -ddump-types or -ddump-tc
1298 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1299 (dumpTcRn short_dump) ;
1301 -- Dump bindings if -ddump-tc
1302 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1305 short_dump = pprTcGblEnv env
1306 full_dump = pprLHsBinds (tcg_binds env)
1307 -- NB: foreign x-d's have undefined's in their types;
1308 -- hence can't show the tc_fords
1311 = do { dflags <- getDOpts ;
1312 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1313 (dumpTcRn (pprModGuts mod_guts)) ;
1315 -- Dump bindings if -ddump-tc
1316 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1318 full_dump = pprCoreBindings (mg_binds mod_guts)
1320 -- It's unpleasant having both pprModGuts and pprModDetails here
1321 pprTcGblEnv :: TcGblEnv -> SDoc
1322 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1324 tcg_fam_insts = fam_insts,
1326 tcg_imports = imports })
1327 = vcat [ ppr_types insts type_env
1328 , ppr_tycons fam_insts type_env
1330 , ppr_fam_insts fam_insts
1331 , vcat (map ppr rules)
1332 , ppr_gen_tycons (typeEnvTyCons type_env)
1333 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1334 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1336 pprModGuts :: ModGuts -> SDoc
1337 pprModGuts (ModGuts { mg_types = type_env,
1339 = vcat [ ppr_types [] type_env,
1342 ppr_types :: [Instance] -> TypeEnv -> SDoc
1343 ppr_types insts type_env
1344 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1346 dfun_ids = map instanceDFunId insts
1347 ids = [id | id <- typeEnvIds type_env, want_sig id]
1348 want_sig id | opt_PprStyle_Debug = True
1349 | otherwise = isLocalId id &&
1350 isExternalName (idName id) &&
1351 not (id `elem` dfun_ids)
1352 -- isLocalId ignores data constructors, records selectors etc.
1353 -- The isExternalName ignores local dictionary and method bindings
1354 -- that the type checker has invented. Top-level user-defined things
1355 -- have External names.
1357 ppr_tycons :: [FamInst] -> TypeEnv -> SDoc
1358 ppr_tycons fam_insts type_env
1359 = text "TYPE CONSTRUCTORS" $$ nest 4 (ppr_tydecls tycons)
1361 fi_tycons = map famInstTyCon fam_insts
1362 tycons = [tycon | tycon <- typeEnvTyCons type_env, want_tycon tycon]
1363 want_tycon tycon | opt_PprStyle_Debug = True
1364 | otherwise = not (isImplicitTyCon tycon) &&
1365 isExternalName (tyConName tycon) &&
1366 not (tycon `elem` fi_tycons)
1368 ppr_insts :: [Instance] -> SDoc
1369 ppr_insts [] = empty
1370 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1372 ppr_fam_insts :: [FamInst] -> SDoc
1373 ppr_fam_insts [] = empty
1374 ppr_fam_insts fam_insts =
1375 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1377 ppr_sigs :: [Var] -> SDoc
1379 -- Print type signatures; sort by OccName
1380 = vcat (map ppr_sig (sortLe le_sig ids))
1382 le_sig id1 id2 = getOccName id1 <= getOccName id2
1383 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1385 ppr_tydecls :: [TyCon] -> SDoc
1387 -- Print type constructor info; sort by OccName
1388 = vcat (map ppr_tycon (sortLe le_sig tycons))
1390 le_sig tycon1 tycon2 = getOccName tycon1 <= getOccName tycon2
1392 | isCoercionTyCon tycon = ptext SLIT("coercion") <+> ppr tycon
1393 | otherwise = ppr (tyThingToIfaceDecl (ATyCon tycon))
1395 ppr_rules :: [CoreRule] -> SDoc
1396 ppr_rules [] = empty
1397 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1398 nest 4 (pprRules rs),
1401 ppr_gen_tycons [] = empty
1402 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1403 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]