2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
5 \section[TcModule]{Typechecking a whole module}
10 tcRnStmt, tcRnExpr, tcRnType,
22 #include "HsVersions.h"
26 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
88 import {- Kind parts of -} Type
98 import Control.Monad ( unless )
99 import Data.Maybe ( isJust )
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 $$ ppr boot_insts $$
505 ppr local_export_set $$ ppr boot_exports)) ;
506 ; mapM_ check_export (concatMap availNames boot_exports)
507 ; dfun_binds <- mapM check_inst boot_insts
508 ; unless (null boot_fam_insts) $
509 panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++
510 "instances in boot files yet...")
511 -- FIXME: Why? The actual comparison is not hard, but what would
512 -- be the equivalent to the dfun bindings returned for class
513 -- instances? We can't easily equate tycons...
514 ; return (tcg_env { tcg_binds = binds `unionBags` unionManyBags dfun_binds }) }
516 check_export name -- Name is exported by the boot iface
517 | name `elem` dfun_names = return ()
518 | isWiredInName name = return () -- No checking for wired-in names. In particular,
519 -- 'error' is handled by a rather gross hack
520 -- (see comments in GHC.Err.hs-boot)
521 | isImplicitTyThing boot_thing = return ()
522 | Just real_thing <- lookupTypeEnv local_type_env name
523 = do { checkTc (name `elemNameSet` local_export_set)
524 (missingBootThing boot_thing "exported by")
526 ; let boot_decl = tyThingToIfaceDecl boot_thing
527 real_decl = tyThingToIfaceDecl real_thing
528 ; checkTc (checkBootDecl boot_decl real_decl)
529 (bootMisMatch boot_thing boot_decl real_decl) }
530 -- The easiest way to check compatibility is to convert to
531 -- iface syntax, where we already have good comparison functions
534 = addErrTc (missingBootThing boot_thing "defined in")
536 boot_thing = lookupTypeEnv boot_type_env name
537 `orElse` pprPanic "checkHiBootIface" (ppr name)
539 dfun_names = map getName boot_insts
541 local_export_set :: NameSet
542 local_export_set = availsToNameSet local_exports
545 = case [dfun | inst <- local_insts,
546 let dfun = instanceDFunId inst,
547 idType dfun `tcEqType` boot_inst_ty ] of
548 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
549 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
551 boot_dfun = instanceDFunId boot_inst
552 boot_inst_ty = idType boot_dfun
553 local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty
557 missingBootThing thing what
558 = ppr thing <+> ptext SLIT("is exported by the hs-boot file, but not")
559 <+> text what <+> ptext SLIT("the module")
561 bootMisMatch thing boot_decl real_decl
562 = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"),
563 ptext SLIT("Main module:") <+> ppr real_decl,
564 ptext SLIT("Boot file: ") <+> ppr boot_decl]
568 2 (ptext SLIT("is defined in the hs-boot file, but not in the module itself"))
572 %************************************************************************
574 Type-checking the top level of a module
576 %************************************************************************
578 tcRnGroup takes a bunch of top-level source-code declarations, and
580 * gets supporting declarations from interface files
583 * and augments the TcGblEnv with the results
585 In Template Haskell it may be called repeatedly for each group of
586 declarations. It expects there to be an incoming TcGblEnv in the
587 monad; it augments it and returns the new TcGblEnv.
590 ------------------------------------------------
591 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
593 = do { -- Bring top level binders into scope
594 tcg_env <- importsFromLocalDecls group ;
595 setGblEnv tcg_env $ do {
597 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
599 -- Rename the source decls
600 (tcg_env, rn_decls) <- rnSrcDecls group ;
603 -- save the renamed syntax, if we want it
605 | Just grp <- tcg_rn_decls tcg_env
606 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
610 -- Dump trace of renaming part
611 rnDump (ppr rn_decls) ;
613 return (tcg_env', rn_decls)
616 ------------------------------------------------
617 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
618 tcTopSrcDecls boot_details
619 (HsGroup { hs_tyclds = tycl_decls,
620 hs_instds = inst_decls,
621 hs_derivds = deriv_decls,
622 hs_fords = foreign_decls,
623 hs_defds = default_decls,
624 hs_ruleds = rule_decls,
625 hs_valds = val_binds })
626 = do { -- Type-check the type and class decls, and all imported decls
627 -- The latter come in via tycl_decls
628 traceTc (text "Tc2") ;
630 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
631 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
632 -- an error we'd better stop now, to avoid a cascade
634 -- Make these type and class decls available to stuff slurped from interface files
635 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
638 setGblEnv tcg_env $ do {
639 -- Source-language instances, including derivings,
640 -- and import the supporting declarations
641 traceTc (text "Tc3") ;
642 (tcg_env, inst_infos, deriv_binds)
643 <- tcInstDecls1 tycl_decls inst_decls deriv_decls;
644 setGblEnv tcg_env $ do {
646 -- Foreign import declarations next. No zonking necessary
647 -- here; we can tuck them straight into the global environment.
648 traceTc (text "Tc4") ;
649 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
650 tcExtendGlobalValEnv fi_ids $ do {
652 -- Default declarations
653 traceTc (text "Tc4a") ;
654 default_tys <- tcDefaults default_decls ;
655 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
657 -- Value declarations next
658 -- We also typecheck any extra binds that came out
659 -- of the "deriving" process (deriv_binds)
660 traceTc (text "Tc5") ;
661 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
662 setLclTypeEnv tcl_env $ do {
664 -- Second pass over class and instance declarations,
665 traceTc (text "Tc6") ;
666 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
667 showLIE (text "after instDecls2") ;
670 -- They need to be zonked, so we return them
671 traceTc (text "Tc7") ;
672 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
675 rules <- tcRules rule_decls ;
678 traceTc (text "Tc7a") ;
679 tcg_env <- getGblEnv ;
680 let { all_binds = tc_val_binds `unionBags`
681 inst_binds `unionBags`
684 -- Extend the GblEnv with the (as yet un-zonked)
685 -- bindings, rules, foreign decls
686 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
687 tcg_rules = tcg_rules tcg_env ++ rules,
688 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
689 return (tcg_env', tcl_env)
694 %************************************************************************
698 %************************************************************************
701 checkMain :: TcM TcGblEnv
702 -- If we are in module Main, check that 'main' is defined.
704 = do { ghc_mode <- getGhcMode ;
705 tcg_env <- getGblEnv ;
707 let { main_mod = mainModIs dflags ;
708 main_fn = case mainFunIs dflags of {
709 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
710 Nothing -> main_RDR_Unqual } } ;
712 check_main ghc_mode tcg_env main_mod main_fn
716 check_main ghc_mode tcg_env main_mod main_fn
718 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
722 = addErrCtxt mainCtxt $
723 do { mb_main <- lookupSrcOcc_maybe main_fn
724 -- Check that 'main' is in scope
725 -- It might be imported from another module!
727 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
731 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
732 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
733 -- :Main.main :: IO () = runMainIO main
735 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
738 -- See Note [Root-main Id]
739 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
740 (mkVarOccFS FSLIT("main"))
741 (getSrcLoc main_name)
742 ; root_main_id = Id.mkExportedLocalId root_main_name ty
743 ; main_bind = noLoc (VarBind root_main_id main_expr) }
745 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
747 tcg_dus = tcg_dus tcg_env
748 `plusDU` usesOnly (unitFV main_name)
749 -- Record the use of 'main', so that we don't
750 -- complain about it being defined but not used
754 mod = tcg_mod tcg_env
756 complain_no_main | ghc_mode == Interactive = return ()
757 | otherwise = failWithTc noMainMsg
758 -- In interactive mode, don't worry about the absence of 'main'
759 -- In other modes, fail altogether, so that we don't go on
760 -- and complain a second time when processing the export list.
762 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
763 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
764 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
769 The function that the RTS invokes is always :Main.main, which we call
770 root_main_id. (Because GHC allows the user to have a module not
771 called Main as the main module, we can't rely on the main function
772 being called "Main.main". That's why root_main_id has a fixed module
775 This is unusual: it's a LocalId whose Name has a Module from another
776 module. Tiresomely, we must filter it out again in MkIface, les we
777 get two defns for 'main' in the interface file!
780 %*********************************************************
784 %*********************************************************
788 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
789 setInteractiveContext hsc_env icxt thing_inside
791 -- Initialise the tcg_inst_env with instances
792 -- from all home modules. This mimics the more selective
793 -- call to hptInstances in tcRnModule
794 dfuns = hptInstances hsc_env (\mod -> True)
796 updGblEnv (\env -> env {
797 tcg_rdr_env = ic_rn_gbl_env icxt,
798 tcg_type_env = ic_type_env icxt,
799 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
801 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
803 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
810 -> InteractiveContext
812 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
813 -- The returned [Name] is the same as the input except for
814 -- ExprStmt, in which case the returned [Name] is [itName]
816 -- The returned TypecheckedHsExpr is of type IO [ () ],
817 -- a list of the bound values, coerced to ().
819 tcRnStmt hsc_env ictxt rdr_stmt
820 = initTcPrintErrors hsc_env iNTERACTIVE $
821 setInteractiveContext hsc_env ictxt $ do {
823 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
824 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
825 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
828 -- The real work is done here
829 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
830 zonked_expr <- zonkTopLExpr tc_expr ;
831 zonked_ids <- zonkTopBndrs bound_ids ;
833 -- None of the Ids should be of unboxed type, because we
834 -- cast them all to HValues in the end!
835 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
837 traceTc (text "tcs 1") ;
838 let { -- (a) Make all the bound ids "global" ids, now that
839 -- they're notionally top-level bindings. This is
840 -- important: otherwise when we come to compile an expression
841 -- using these ids later, the byte code generator will consider
842 -- the occurrences to be free rather than global.
844 -- (b) Tidy their types; this is important, because :info may
845 -- ask to look at them, and :info expects the things it looks
846 -- up to have tidy types
847 global_ids = map globaliseAndTidy zonked_ids ;
849 -- Update the interactive context
850 rn_env = ic_rn_local_env ictxt ;
851 type_env = ic_type_env ictxt ;
853 bound_names = map idName global_ids ;
854 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
856 {- ---------------------------------------------
857 At one stage I removed any shadowed bindings from the type_env;
858 they are inaccessible but might, I suppose, cause a space leak if we leave them there.
859 However, with Template Haskell they aren't necessarily inaccessible. Consider this
861 Prelude> let f n = n * 2 :: Int
862 Prelude> fName <- runQ [| f |]
863 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
865 Prelude> let f n = n * 3 :: Int
866 Prelude> $(return $ AppE fName (LitE (IntegerL 7)))
867 In the last line we use 'fName', which resolves to the *first* 'f'
868 in scope. If we delete it from the type env, GHCi crashes because
869 it doesn't expect that.
871 Hence this code is commented out
873 shadowed = [ n | name <- bound_names,
874 let rdr_name = mkRdrUnqual (nameOccName name),
875 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
876 filtered_type_env = delListFromNameEnv type_env shadowed ;
877 -------------------------------------------------- -}
879 new_type_env = extendTypeEnvWithIds type_env global_ids ;
880 new_ic = ictxt { ic_rn_local_env = new_rn_env,
881 ic_type_env = new_type_env }
884 dumpOptTcRn Opt_D_dump_tc
885 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
886 text "Typechecked expr" <+> ppr zonked_expr]) ;
888 returnM (new_ic, bound_names, zonked_expr)
891 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
892 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
894 globaliseAndTidy :: Id -> Id
896 -- Give the Id a Global Name, and tidy its type
897 = Id.setIdType (globaliseId VanillaGlobal id) tidy_type
899 tidy_type = tidyTopType (idType id)
902 Here is the grand plan, implemented in tcUserStmt
904 What you type The IO [HValue] that hscStmt returns
905 ------------- ------------------------------------
906 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
909 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
912 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
913 [NB: result not printed] bindings: [it]
915 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
916 result showable) bindings: [it]
918 expr (of non-IO type,
919 result not showable) ==> error
923 ---------------------------
924 type PlanResult = ([Id], LHsExpr Id)
925 type Plan = TcM PlanResult
927 runPlans :: [Plan] -> TcM PlanResult
928 -- Try the plans in order. If one fails (by raising an exn), try the next.
929 -- If one succeeds, take it.
930 runPlans [] = panic "runPlans"
932 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
935 mkPlan :: LStmt Name -> TcM PlanResult
936 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
937 = do { uniq <- newUnique -- is treated very specially
938 ; let fresh_it = itName uniq
939 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
940 matches = [mkMatch [] expr emptyLocalBinds]
941 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
942 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
943 (HsVar bindIOName) noSyntaxExpr
944 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
945 (HsVar thenIOName) placeHolderType
948 -- [it <- e; print it] but not if it::()
950 -- [let it = e; print it]
951 ; runPlans [ -- Plan A
952 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
953 ; it_ty <- zonkTcType (idType it_id)
954 ; ifM (isUnitTy it_ty) failM
957 -- Plan B; a naked bind statment
958 tcGhciStmts [bind_stmt],
960 -- Plan C; check that the let-binding is typeable all by itself.
961 -- If not, fail; if so, try to print it.
962 -- The two-step process avoids getting two errors: one from
963 -- the expression itself, and one from the 'print it' part
964 -- This two-step story is very clunky, alas
965 do { checkNoErrs (tcGhciStmts [let_stmt])
966 --- checkNoErrs defeats the error recovery of let-bindings
967 ; tcGhciStmts [let_stmt, print_it] }
970 mkPlan stmt@(L loc (BindStmt {}))
971 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
972 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
973 (HsVar thenIOName) placeHolderType
975 ; print_bind_result <- doptM Opt_PrintBindResult
976 ; let print_plan = do
977 { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
978 ; v_ty <- zonkTcType (idType v_id)
979 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
983 -- [stmt; print v] but not if v::()
985 ; runPlans ((if print_bind_result then [print_plan] else []) ++
986 [tcGhciStmts [stmt]])
992 ---------------------------
993 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
995 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
996 ret_id <- tcLookupId returnIOName ; -- return @ IO
998 io_ty = mkTyConApp ioTyCon [] ;
999 ret_ty = mkListTy unitTy ;
1000 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
1001 tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts
1002 (emptyRefinement, io_ret_ty) ;
1004 names = map unLoc (collectLStmtsBinders stmts) ;
1006 -- mk_return builds the expression
1007 -- returnIO @ [()] [coerce () x, .., coerce () z]
1009 -- Despite the inconvenience of building the type applications etc,
1010 -- this *has* to be done in type-annotated post-typecheck form
1011 -- because we are going to return a list of *polymorphic* values
1012 -- coerced to type (). If we built a *source* stmt
1013 -- return [coerce x, ..., coerce z]
1014 -- then the type checker would instantiate x..z, and we wouldn't
1015 -- get their *polymorphic* values. (And we'd get ambiguity errs
1016 -- if they were overloaded, since they aren't applied to anything.)
1017 mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty])
1018 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1019 mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy])
1023 -- OK, we're ready to typecheck the stmts
1024 traceTc (text "tcs 2") ;
1025 ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ ->
1026 mappM tcLookupId names ;
1027 -- Look up the names right in the middle,
1028 -- where they will all be in scope
1030 -- Simplify the context
1031 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1032 -- checkNoErrs ensures that the plan fails if context redn fails
1034 return (ids, mkHsDictLet const_binds $
1035 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1040 tcRnExpr just finds the type of an expression
1044 -> InteractiveContext
1047 tcRnExpr hsc_env ictxt rdr_expr
1048 = initTcPrintErrors hsc_env iNTERACTIVE $
1049 setInteractiveContext hsc_env ictxt $ do {
1051 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1054 -- Now typecheck the expression;
1055 -- it might have a rank-2 type (e.g. :t runST)
1056 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1057 ((qtvs, dict_insts, _), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1058 tcSimplifyInteractive lie_top ;
1060 let { all_expr_ty = mkForAllTys qtvs $
1061 mkFunTys (map (idType . instToId) dict_insts) $
1063 zonkTcType all_expr_ty
1066 smpl_doc = ptext SLIT("main expression")
1069 tcRnType just finds the kind of a type
1073 -> InteractiveContext
1076 tcRnType hsc_env ictxt rdr_type
1077 = initTcPrintErrors hsc_env iNTERACTIVE $
1078 setInteractiveContext hsc_env ictxt $ do {
1080 rn_type <- rnLHsType doc rdr_type ;
1083 -- Now kind-check the type
1084 (ty', kind) <- kcHsType rn_type ;
1088 doc = ptext SLIT("In GHCi input")
1094 %************************************************************************
1096 More GHCi stuff, to do with browsing and getting info
1098 %************************************************************************
1102 -- ASSUMES that the module is either in the HomePackageTable or is
1103 -- a package module with an interface on disk. If neither of these is
1104 -- true, then the result will be an error indicating the interface
1105 -- could not be found.
1106 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo])
1107 getModuleExports hsc_env mod
1110 checkMods = ic_toplev_scope ic ++ ic_exports ic
1112 initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod checkMods)
1114 -- Get the export avail info and also load all orphan and family-instance
1115 -- modules. Finally, check that the family instances of all modules in the
1116 -- interactive context are consistent (these modules are in the second
1118 tcGetModuleExports :: Module -> [Module] -> TcM [AvailInfo]
1119 tcGetModuleExports mod directlyImpMods
1120 = do { let doc = ptext SLIT("context for compiling statements")
1121 ; iface <- initIfaceTcRn $ loadSysInterface doc mod
1123 -- Load any orphan-module and family instance-module
1124 -- interfaces, so their instances are visible.
1125 ; loadOrphanModules (dep_orphs (mi_deps iface)) False
1126 ; loadOrphanModules (dep_finsts (mi_deps iface)) True
1128 -- Check that the family instances of all directly loaded
1129 -- modules are consistent.
1130 ; checkFamInstConsistency (dep_finsts (mi_deps iface)) directlyImpMods
1132 ; ifaceExportNames (mi_exports iface)
1135 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1136 tcRnLookupRdrName hsc_env rdr_name
1137 = initTcPrintErrors hsc_env iNTERACTIVE $
1138 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1139 lookup_rdr_name rdr_name
1141 lookup_rdr_name rdr_name = do {
1142 -- If the identifier is a constructor (begins with an
1143 -- upper-case letter), then we need to consider both
1144 -- constructor and type class identifiers.
1145 let { rdr_names = dataTcOccs rdr_name } ;
1147 -- results :: [Either Messages Name]
1148 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1150 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1151 -- The successful lookups will be (Just name)
1152 let { (warns_s, good_names) = unzip [ (msgs, name)
1153 | (msgs, Just name) <- results] ;
1154 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1156 -- Fail if nothing good happened, else add warnings
1157 if null good_names then
1158 -- No lookup succeeded, so
1159 -- pick the first error message and report it
1160 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1161 -- while the other is "X is not in scope",
1162 -- we definitely want the former; but we might pick the latter
1163 do { addMessages (head errs_s) ; failM }
1164 else -- Add deprecation warnings
1165 mapM_ addMessages warns_s ;
1170 tcRnRecoverDataCon :: HscEnv -> a -> IO (Maybe DataCon)
1171 tcRnRecoverDataCon hsc_env a
1172 = initTcPrintErrors hsc_env iNTERACTIVE $
1173 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1174 do name <- recoverDataCon a
1175 tcLookupDataCon name
1177 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1178 tcRnLookupName hsc_env name
1179 = initTcPrintErrors hsc_env iNTERACTIVE $
1180 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1184 tcRnGetInfo :: HscEnv
1186 -> IO (Maybe (TyThing, Fixity, [Instance]))
1188 -- Used to implemnent :info in GHCi
1190 -- Look up a RdrName and return all the TyThings it might be
1191 -- A capitalised RdrName is given to us in the DataName namespace,
1192 -- but we want to treat it as *both* a data constructor
1193 -- *and* as a type or class constructor;
1194 -- hence the call to dataTcOccs, and we return up to two results
1195 tcRnGetInfo hsc_env name
1196 = initTcPrintErrors hsc_env iNTERACTIVE $
1197 let ictxt = hsc_IC hsc_env in
1198 setInteractiveContext hsc_env ictxt $ do
1200 -- Load the interface for all unqualified types and classes
1201 -- That way we will find all the instance declarations
1202 -- (Packages have not orphan modules, and we assume that
1203 -- in the home package all relevant modules are loaded.)
1204 loadUnqualIfaces ictxt
1206 thing <- tcLookupGlobal name
1207 fixity <- lookupFixityRn name
1208 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1209 return (thing, fixity, ispecs)
1211 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1212 -- Filter the instances by the ones whose tycons (or clases resp)
1213 -- are in scope unqualified. Otherwise we list a whole lot too many!
1214 lookupInsts print_unqual (AClass cls)
1215 = do { inst_envs <- tcGetInstEnvs
1217 | ispec <- classInstances inst_envs cls
1218 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1220 lookupInsts print_unqual (ATyCon tc)
1221 = do { eps <- getEps -- Load all instances for all classes that are
1222 -- in the type environment (which are all the ones
1223 -- we've seen in any interface file so far)
1224 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1226 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1227 , let dfun = instanceDFunId ispec
1229 , plausibleDFun print_unqual dfun ] }
1231 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1232 tc_name = tyConName tc
1234 lookupInsts print_unqual other = return []
1236 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1237 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1239 ok name | isBuiltInSyntax name = True
1240 | isExternalName name =
1241 isNothing $ fst print_unqual (nameModule name)
1245 loadUnqualIfaces :: InteractiveContext -> TcM ()
1246 -- Load the home module for everything that is in scope unqualified
1247 -- This is so that we can accurately report the instances for
1249 loadUnqualIfaces ictxt
1251 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1253 unqual_mods = [ nameModule name
1254 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1255 let name = gre_name gre,
1256 not (isInternalName name),
1257 isTcOcc (nameOccName name), -- Types and classes only
1258 unQualOK gre ] -- In scope unqualified
1259 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1263 %************************************************************************
1267 %************************************************************************
1270 rnDump :: SDoc -> TcRn ()
1271 -- Dump, with a banner, if -ddump-rn
1272 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1274 tcDump :: TcGblEnv -> TcRn ()
1276 = do { dflags <- getDOpts ;
1278 -- Dump short output if -ddump-types or -ddump-tc
1279 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1280 (dumpTcRn short_dump) ;
1282 -- Dump bindings if -ddump-tc
1283 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1286 short_dump = pprTcGblEnv env
1287 full_dump = pprLHsBinds (tcg_binds env)
1288 -- NB: foreign x-d's have undefined's in their types;
1289 -- hence can't show the tc_fords
1292 = do { dflags <- getDOpts ;
1293 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1294 (dumpTcRn (pprModGuts mod_guts)) ;
1296 -- Dump bindings if -ddump-tc
1297 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1299 full_dump = pprCoreBindings (mg_binds mod_guts)
1301 -- It's unpleasant having both pprModGuts and pprModDetails here
1302 pprTcGblEnv :: TcGblEnv -> SDoc
1303 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1305 tcg_fam_insts = fam_insts,
1307 tcg_imports = imports })
1308 = vcat [ ppr_types insts type_env
1309 , ppr_tycons fam_insts type_env
1311 , ppr_fam_insts fam_insts
1312 , vcat (map ppr rules)
1313 , ppr_gen_tycons (typeEnvTyCons type_env)
1314 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1315 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1317 pprModGuts :: ModGuts -> SDoc
1318 pprModGuts (ModGuts { mg_types = type_env,
1320 = vcat [ ppr_types [] type_env,
1323 ppr_types :: [Instance] -> TypeEnv -> SDoc
1324 ppr_types insts type_env
1325 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1327 dfun_ids = map instanceDFunId insts
1328 ids = [id | id <- typeEnvIds type_env, want_sig id]
1329 want_sig id | opt_PprStyle_Debug = True
1330 | otherwise = isLocalId id &&
1331 isExternalName (idName id) &&
1332 not (id `elem` dfun_ids)
1333 -- isLocalId ignores data constructors, records selectors etc.
1334 -- The isExternalName ignores local dictionary and method bindings
1335 -- that the type checker has invented. Top-level user-defined things
1336 -- have External names.
1338 ppr_tycons :: [FamInst] -> TypeEnv -> SDoc
1339 ppr_tycons fam_insts type_env
1340 = text "TYPE CONSTRUCTORS" $$ nest 4 (ppr_tydecls tycons)
1342 fi_tycons = map famInstTyCon fam_insts
1343 tycons = [tycon | tycon <- typeEnvTyCons type_env, want_tycon tycon]
1344 want_tycon tycon | opt_PprStyle_Debug = True
1345 | otherwise = not (isImplicitTyCon tycon) &&
1346 isExternalName (tyConName tycon) &&
1347 not (tycon `elem` fi_tycons)
1349 ppr_insts :: [Instance] -> SDoc
1350 ppr_insts [] = empty
1351 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1353 ppr_fam_insts :: [FamInst] -> SDoc
1354 ppr_fam_insts [] = empty
1355 ppr_fam_insts fam_insts =
1356 text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts)
1358 ppr_sigs :: [Var] -> SDoc
1360 -- Print type signatures; sort by OccName
1361 = vcat (map ppr_sig (sortLe le_sig ids))
1363 le_sig id1 id2 = getOccName id1 <= getOccName id2
1364 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1366 ppr_tydecls :: [TyCon] -> SDoc
1368 -- Print type constructor info; sort by OccName
1369 = vcat (map ppr_tycon (sortLe le_sig tycons))
1371 le_sig tycon1 tycon2 = getOccName tycon1 <= getOccName tycon2
1373 | isCoercionTyCon tycon = ptext SLIT("coercion") <+> ppr tycon
1374 | otherwise = ppr (tyThingToIfaceDecl (ATyCon tycon))
1376 ppr_rules :: [CoreRule] -> SDoc
1377 ppr_rules [] = empty
1378 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1379 nest 4 (pprRules rs),
1382 ppr_gen_tycons [] = empty
1383 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1384 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]