2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
9 tcRnStmt, tcRnExpr, tcRnType,
20 #include "HsVersions.h"
24 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
27 import DynFlags ( DynFlag(..), DynFlags(..), dopt, GhcMode(..) )
28 import StaticFlags ( opt_PprStyle_Debug )
29 import Packages ( checkForPackageConflicts, mkHomeModules )
30 import HsSyn ( HsModule(..), HsExtCore(..), HsGroup(..), LHsDecl,
31 SpliceDecl(..), HsBind(..), LHsBinds,
32 emptyRdrGroup, emptyRnGroup, appendGroups, plusHsValBinds,
33 nlHsApp, nlHsVar, pprLHsBinds )
34 import RdrHsSyn ( findSplice )
36 import PrelNames ( runMainIOName, rootMainName, mAIN,
38 import RdrName ( RdrName, mkRdrUnqual, emptyGlobalRdrEnv )
39 import TcHsSyn ( zonkTopDecls )
40 import TcExpr ( tcInferRho )
42 import TcType ( tidyTopType, tcEqType, mkTyVarTys, substTyWith )
43 import Inst ( showLIE )
44 import InstEnv ( extendInstEnvList, Instance, pprInstances, instanceDFunId )
45 import TcBinds ( tcTopBinds, tcHsBootSigs )
46 import TcDefaults ( tcDefaults )
47 import TcEnv ( tcExtendGlobalValEnv, iDFunId )
48 import TcRules ( tcRules )
49 import TcForeign ( tcForeignImports, tcForeignExports )
50 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
51 import TcIface ( tcExtCoreBindings, tcHiBootIface )
52 import TcSimplify ( tcSimplifyTop )
53 import TcTyClsDecls ( tcTyAndClassDecls )
54 import LoadIface ( loadOrphanModules )
55 import RnNames ( importsFromLocalDecls, rnImports, rnExports,
56 reportUnusedNames, reportDeprecations )
57 import RnEnv ( lookupSrcOcc_maybe )
58 import RnSource ( rnSrcDecls, rnTyClDecls, checkModDeprec )
59 import PprCore ( pprRules, pprCoreBindings )
60 import CoreSyn ( CoreRule, bindersOfBinds )
61 import DataCon ( dataConWrapId )
62 import ErrUtils ( Messages, mkDumpDoc, showPass )
63 import Id ( Id, mkExportedLocalId, isLocalId, idName, idType )
65 import Module ( Module, ModuleEnv, mkModule, moduleEnvElts, elemModuleEnv )
66 import OccName ( mkVarOcc )
67 import Name ( Name, NamedThing(..), isExternalName, getSrcLoc, isWiredInName )
69 import TyCon ( tyConHasGenerics, isSynTyCon, getSynTyConDefn, tyConKind )
70 import SrcLoc ( srcLocSpan, Located(..), noLoc )
71 import DriverPhases ( HscSource(..), isHsBoot )
72 import HscTypes ( ModGuts(..), ModDetails(..), emptyModDetails,
73 HscEnv(..), ExternalPackageState(..),
74 IsBootInterface, noDependencies,
75 Deprecs( NoDeprecs ), plusDeprecs,
76 ForeignStubs(NoStubs), TyThing(..),
77 TypeEnv, lookupTypeEnv, hptInstances,
78 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons, typeEnvElts,
84 import HsSyn ( HsStmtContext(..), Stmt(..), HsExpr(..),
85 HsLocalBinds(..), HsValBinds(..),
86 LStmt, LHsExpr, LHsType, mkVarBind,
87 collectLStmtsBinders, collectLStmtBinders, nlVarPat,
88 placeHolderType, noSyntaxExpr )
89 import RdrName ( GlobalRdrElt(..), globalRdrEnvElts,
90 unQualOK, lookupLocalRdrEnv, extendLocalRdrEnv )
91 import RnSource ( addTcgDUs )
92 import TcHsSyn ( mkHsDictLet, zonkTopLExpr, zonkTopBndrs )
93 import TcHsType ( kcHsType )
94 import TcMType ( zonkTcType, zonkQuantifiedTyVar )
95 import TcMatches ( tcStmts, tcDoStmt )
96 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
97 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType, isTauTy,
98 isUnLiftedType, tyClsNamesOfDFunHead, tyClsNamesOfType, isUnitTy )
99 import TcEnv ( tcLookupTyCon, tcLookupId, tcLookupGlobal )
100 import RnTypes ( rnLHsType )
101 import Inst ( tcGetInstEnvs )
102 import InstEnv ( classInstances, instEnvElts )
103 import RnExpr ( rnStmts, rnLExpr )
104 import LoadIface ( loadSrcInterface, loadSysInterface )
105 import IfaceEnv ( ifaceExportNames )
106 import Module ( moduleSetElts, mkModuleSet )
107 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
108 import Id ( setIdType )
109 import MkId ( unsafeCoerceId )
110 import TyCon ( tyConName )
111 import TysWiredIn ( mkListTy, unitTy )
112 import IdInfo ( GlobalIdDetails(..) )
114 import Var ( globaliseId )
115 import Name ( nameOccName, nameModule, isBuiltInSyntax )
116 import OccName ( isTcOcc )
117 import NameEnv ( delListFromNameEnv )
118 import PrelNames ( iNTERACTIVE, ioTyConName, printName, itName,
119 bindIOName, thenIOName, returnIOName )
120 import HscTypes ( InteractiveContext(..),
121 ModIface(..), icPrintUnqual,
123 import BasicTypes ( Fixity )
124 import SrcLoc ( unLoc, noSrcSpan )
127 import FastString ( mkFastString )
128 import Maybes ( MaybeErr(..) )
129 import Util ( sortLe )
130 import Bag ( unionBags, snocBag, emptyBag, unitBag, unionManyBags )
132 import Maybe ( isJust )
137 %************************************************************************
139 Typecheck and rename a module
141 %************************************************************************
147 -> Bool -- True <=> save renamed syntax
148 -> Located (HsModule RdrName)
149 -> IO (Messages, Maybe TcGblEnv)
151 tcRnModule hsc_env hsc_src save_rn_decls
152 (L loc (HsModule maybe_mod export_ies
153 import_decls local_decls mod_deprec))
154 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
156 let { this_mod = case maybe_mod of
157 Nothing -> mAIN -- 'module M where' is omitted
158 Just (L _ mod) -> mod } ; -- The normal case
160 initTc hsc_env hsc_src this_mod $
163 -- Deal with imports; sets tcg_rdr_env, tcg_imports
164 (rdr_env, imports) <- rnImports import_decls ;
166 let { dep_mods :: ModuleEnv (Module, IsBootInterface)
167 ; dep_mods = imp_dep_mods imports
169 -- We want instance declarations from all home-package
170 -- modules below this one, including boot modules, except
171 -- ourselves. The 'except ourselves' is so that we don't
172 -- get the instances from this module's hs-boot file
173 ; want_instances :: Module -> Bool
174 ; want_instances mod = mod `elemModuleEnv` dep_mods
176 ; home_insts = hptInstances hsc_env want_instances
179 -- Record boot-file info in the EPS, so that it's
180 -- visible to loadHiBootInterface in tcRnSrcDecls,
181 -- and any other incrementally-performed imports
182 updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
184 checkConflicts imports this_mod $ do {
186 -- Update the gbl env
188 gbl { tcg_rdr_env = rdr_env,
189 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts,
190 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
191 tcg_rn_decls = if save_rn_decls then
197 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
198 -- Fail if there are any errors so far
199 -- The error printing (if needed) takes advantage
200 -- of the tcg_env we have now set
203 -- Load any orphan-module interfaces, so that
204 -- their rules and instance decls will be found
205 loadOrphanModules (imp_orphs imports) ;
207 traceRn (text "rn1a") ;
208 -- Rename and type check the declarations
209 tcg_env <- if isHsBoot hsc_src then
210 tcRnHsBootDecls local_decls
212 tcRnSrcDecls local_decls ;
213 setGblEnv tcg_env $ do {
215 traceRn (text "rn3") ;
217 -- Report the use of any deprecated things
218 -- We do this before processsing the export list so
219 -- that we don't bleat about re-exporting a deprecated
220 -- thing (especially via 'module Foo' export item)
221 -- Only uses in the body of the module are complained about
222 reportDeprecations tcg_env ;
224 -- Process the export list
225 exports <- rnExports (isJust maybe_mod) export_ies ;
227 -- Check whether the entire module is deprecated
228 -- This happens only once per module
229 let { mod_deprecs = checkModDeprec mod_deprec } ;
231 -- Add exports and deprecations to envt
232 let { final_env = tcg_env { tcg_exports = exports,
233 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
234 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
236 -- A module deprecation over-rides the earlier ones
239 -- Report unused names
240 reportUnusedNames export_ies final_env ;
242 -- Dump output and return
248 -- The program is not allowed to contain two modules with the same
249 -- name, and we check for that here. It could happen if the home package
250 -- contains a module that is also present in an external package, for example.
251 checkConflicts imports this_mod and_then = do
254 dep_mods = this_mod : map fst (moduleEnvElts (imp_dep_mods imports))
255 -- don't forget to include the current module!
257 mb_dep_pkgs = checkForPackageConflicts
258 dflags dep_mods (imp_dep_pkgs imports)
264 updGblEnv (\gbl -> gbl{ tcg_home_mods = mkHomeModules dep_mods })
269 %************************************************************************
271 Type-checking external-core modules
273 %************************************************************************
276 tcRnExtCore :: HscEnv
278 -> IO (Messages, Maybe ModGuts)
279 -- Nothing => some error occurred
281 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
282 -- The decls are IfaceDecls; all names are original names
283 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
285 initTc hsc_env ExtCoreFile this_mod $ do {
287 let { ldecls = map noLoc decls } ;
289 -- Deal with the type declarations; first bring their stuff
290 -- into scope, then rname them, then type check them
291 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
293 setGblEnv tcg_env $ do {
295 rn_decls <- rnTyClDecls ldecls ;
298 -- Dump trace of renaming part
299 rnDump (ppr rn_decls) ;
301 -- Typecheck them all together so that
302 -- any mutually recursive types are done right
303 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
304 -- Make the new type env available to stuff slurped from interface files
306 setGblEnv tcg_env $ do {
308 -- Now the core bindings
309 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
313 bndrs = bindersOfBinds core_binds ;
314 my_exports = mkNameSet (map idName bndrs) ;
315 -- ToDo: export the data types also?
317 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
319 mod_guts = ModGuts { mg_module = this_mod,
321 mg_usages = [], -- ToDo: compute usage
322 mg_dir_imps = [], -- ??
323 mg_deps = noDependencies, -- ??
324 mg_home_mods = mkHomeModules [], -- ?? wrong!!
325 mg_exports = my_exports,
326 mg_types = final_type_env,
327 mg_insts = tcg_insts tcg_env,
329 mg_binds = core_binds,
332 mg_rdr_env = emptyGlobalRdrEnv,
333 mg_fix_env = emptyFixityEnv,
334 mg_deprecs = NoDeprecs,
338 tcCoreDump mod_guts ;
343 mkFakeGroup decls -- Rather clumsy; lots of unused fields
344 = emptyRdrGroup { hs_tyclds = decls }
348 %************************************************************************
350 Type-checking the top level of a module
352 %************************************************************************
355 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
356 -- Returns the variables free in the decls
357 -- Reason: solely to report unused imports and bindings
359 = do { -- Load the hi-boot interface for this module, if any
360 -- We do this now so that the boot_names can be passed
361 -- to tcTyAndClassDecls, because the boot_names are
362 -- automatically considered to be loop breakers
364 boot_iface <- tcHiBootIface mod ;
366 -- Do all the declarations
367 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_iface decls) ;
369 -- tcSimplifyTop deals with constant or ambiguous InstIds.
370 -- How could there be ambiguous ones? They can only arise if a
371 -- top-level decl falls under the monomorphism
372 -- restriction, and no subsequent decl instantiates its
373 -- type. (Usually, ambiguous type variables are resolved
374 -- during the generalisation step.)
375 traceTc (text "Tc8") ;
376 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
377 -- Setting the global env exposes the instances to tcSimplifyTop
378 -- Setting the local env exposes the local Ids to tcSimplifyTop,
379 -- so that we get better error messages (monomorphism restriction)
381 -- Backsubstitution. This must be done last.
382 -- Even tcSimplifyTop may do some unification.
383 traceTc (text "Tc9") ;
384 let { (tcg_env, _) = tc_envs ;
385 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
386 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
388 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
391 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
392 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
395 tcg_fords = fords' } } ;
397 -- Make the new type env available to stuff slurped from interface files
398 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
400 -- Compare the hi-boot iface (if any) with the real thing
401 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
403 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
406 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
407 -- Loops around dealing with each top level inter-splice group
408 -- in turn, until it's dealt with the entire module
409 tc_rn_src_decls boot_details ds
410 = do { let { (first_group, group_tail) = findSplice ds } ;
411 -- If ds is [] we get ([], Nothing)
413 -- Type check the decls up to, but not including, the first splice
414 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_details first_group ;
416 -- Bale out if errors; for example, error recovery when checking
417 -- the RHS of 'main' can mean that 'main' is not in the envt for
418 -- the subsequent checkMain test
423 -- If there is no splice, we're nearly done
425 Nothing -> do { -- Last thing: check for `main'
426 tcg_env <- checkMain ;
427 return (tcg_env, tcl_env)
430 -- If there's a splice, we must carry on
431 Just (SpliceDecl splice_expr, rest_ds) -> do {
433 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
436 -- Rename the splice expression, and get its supporting decls
437 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
438 failIfErrsM ; -- Don't typecheck if renaming failed
440 -- Execute the splice
441 spliced_decls <- tcSpliceDecls rn_splice_expr ;
443 -- Glue them on the front of the remaining decls and loop
444 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
445 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
450 %************************************************************************
452 Compiling hs-boot source files, and
453 comparing the hi-boot interface with the real thing
455 %************************************************************************
458 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
459 tcRnHsBootDecls decls
460 = do { let { (first_group, group_tail) = findSplice decls }
463 Just stuff -> spliceInHsBootErr stuff
466 -- Rename the declarations
467 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
468 ; setGblEnv tcg_env $ do {
470 -- Todo: check no foreign decls, no rules, no default decls
472 -- Typecheck type/class decls
473 ; traceTc (text "Tc2")
474 ; let tycl_decls = hs_tyclds rn_group
475 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
476 ; setGblEnv tcg_env $ do {
478 -- Typecheck instance decls
479 ; traceTc (text "Tc3")
480 ; (tcg_env, inst_infos, _binds) <- tcInstDecls1 tycl_decls (hs_instds rn_group)
481 ; setGblEnv tcg_env $ do {
483 -- Typecheck value declarations
484 ; traceTc (text "Tc5")
485 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
488 -- No simplification or zonking to do
489 ; traceTc (text "Tc7a")
490 ; gbl_env <- getGblEnv
492 -- Make the final type-env
493 -- Include the dfun_ids so that their type sigs get
494 -- are written into the interface file
495 ; let { type_env0 = tcg_type_env gbl_env
496 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
497 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
498 ; dfun_ids = map iDFunId inst_infos }
499 ; return (gbl_env { tcg_type_env = type_env2 })
502 spliceInHsBootErr (SpliceDecl (L loc _), _)
503 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
506 Once we've typechecked the body of the module, we want to compare what
507 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
510 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
511 -- Compare the hi-boot file for this module (if there is one)
512 -- with the type environment we've just come up with
513 -- In the common case where there is no hi-boot file, the list
514 -- of boot_names is empty.
516 -- The bindings we return give bindings for the dfuns defined in the
517 -- hs-boot file, such as $fbEqT = $fEqT
520 (TcGblEnv { tcg_insts = local_insts, tcg_type_env = local_type_env })
521 (ModDetails { md_insts = boot_insts, md_types = boot_type_env })
522 = do { mapM_ check_one (typeEnvElts boot_type_env)
523 ; dfun_binds <- mapM check_inst boot_insts
524 ; return (unionManyBags dfun_binds) }
530 = case lookupTypeEnv local_type_env name of
531 Nothing -> addErrTc (missingBootThing boot_thing)
532 Just real_thing -> check_thing boot_thing real_thing
534 name = getName boot_thing
536 no_check name = isWiredInName name -- No checking for wired-in names. In particular,
537 -- 'error' is handled by a rather gross hack
538 -- (see comments in GHC.Err.hs-boot)
539 || name `elem` dfun_names
540 dfun_names = map getName boot_insts
543 = case [dfun | inst <- local_insts,
544 let dfun = instanceDFunId inst,
545 idType dfun `tcEqType` boot_inst_ty ] of
546 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
547 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
549 boot_dfun = instanceDFunId boot_inst
550 boot_inst_ty = idType boot_dfun
551 local_boot_dfun = mkExportedLocalId (idName boot_dfun) boot_inst_ty
554 check_thing (ATyCon boot_tc) (ATyCon real_tc)
555 | isSynTyCon boot_tc && isSynTyCon real_tc,
556 defn1 `tcEqType` substTyWith tvs2 (mkTyVarTys tvs1) defn2
559 | tyConKind boot_tc == tyConKind real_tc
562 (tvs1, defn1) = getSynTyConDefn boot_tc
563 (tvs2, defn2) = getSynTyConDefn boot_tc
565 check_thing (AnId boot_id) (AnId real_id)
566 | idType boot_id `tcEqType` idType real_id
569 check_thing (ADataCon dc1) (ADataCon dc2)
570 | idType (dataConWrapId dc1) `tcEqType` idType (dataConWrapId dc2)
573 -- Can't declare a class in a hi-boot file
575 check_thing boot_thing real_thing -- Default case; failure
576 = addErrAt (srcLocSpan (getSrcLoc real_thing))
577 (bootMisMatch real_thing)
580 missingBootThing thing
581 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
583 = ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file")
586 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
590 %************************************************************************
592 Type-checking the top level of a module
594 %************************************************************************
596 tcRnGroup takes a bunch of top-level source-code declarations, and
598 * gets supporting declarations from interface files
601 * and augments the TcGblEnv with the results
603 In Template Haskell it may be called repeatedly for each group of
604 declarations. It expects there to be an incoming TcGblEnv in the
605 monad; it augments it and returns the new TcGblEnv.
608 tcRnGroup :: ModDetails -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
609 -- Returns the variables free in the decls, for unused-binding reporting
610 tcRnGroup boot_details decls
611 = do { -- Rename the declarations
612 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
613 setGblEnv tcg_env $ do {
615 -- Typecheck the declarations
616 tcTopSrcDecls boot_details rn_decls
619 ------------------------------------------------
620 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
622 = do { -- Bring top level binders into scope
623 tcg_env <- importsFromLocalDecls group ;
624 setGblEnv tcg_env $ do {
626 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
628 -- Rename the source decls
629 (tcg_env, rn_decls) <- rnSrcDecls group ;
632 -- save the renamed syntax, if we want it
634 | Just grp <- tcg_rn_decls tcg_env
635 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
639 -- Dump trace of renaming part
640 rnDump (ppr rn_decls) ;
642 return (tcg_env', rn_decls)
645 ------------------------------------------------
646 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
647 tcTopSrcDecls boot_details
648 (HsGroup { hs_tyclds = tycl_decls,
649 hs_instds = inst_decls,
650 hs_fords = foreign_decls,
651 hs_defds = default_decls,
652 hs_ruleds = rule_decls,
653 hs_valds = val_binds })
654 = do { -- Type-check the type and class decls, and all imported decls
655 -- The latter come in via tycl_decls
656 traceTc (text "Tc2") ;
658 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
659 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
660 -- an error we'd better stop now, to avoid a cascade
662 -- Make these type and class decls available to stuff slurped from interface files
663 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
666 setGblEnv tcg_env $ do {
667 -- Source-language instances, including derivings,
668 -- and import the supporting declarations
669 traceTc (text "Tc3") ;
670 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
671 setGblEnv tcg_env $ do {
673 -- Foreign import declarations next. No zonking necessary
674 -- here; we can tuck them straight into the global environment.
675 traceTc (text "Tc4") ;
676 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
677 tcExtendGlobalValEnv fi_ids $ do {
679 -- Default declarations
680 traceTc (text "Tc4a") ;
681 default_tys <- tcDefaults default_decls ;
682 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
684 -- Value declarations next
685 -- We also typecheck any extra binds that came out
686 -- of the "deriving" process (deriv_binds)
687 traceTc (text "Tc5") ;
688 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
689 setLclTypeEnv tcl_env $ do {
691 -- Second pass over class and instance declarations,
692 traceTc (text "Tc6") ;
693 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
694 showLIE (text "after instDecls2") ;
697 -- They need to be zonked, so we return them
698 traceTc (text "Tc7") ;
699 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
702 rules <- tcRules rule_decls ;
705 traceTc (text "Tc7a") ;
706 tcg_env <- getGblEnv ;
707 let { all_binds = tc_val_binds `unionBags`
708 inst_binds `unionBags`
711 -- Extend the GblEnv with the (as yet un-zonked)
712 -- bindings, rules, foreign decls
713 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
714 tcg_rules = tcg_rules tcg_env ++ rules,
715 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
716 return (tcg_env', tcl_env)
721 %************************************************************************
725 %************************************************************************
728 checkMain :: TcM TcGblEnv
729 -- If we are in module Main, check that 'main' is defined.
731 = do { ghci_mode <- getGhciMode ;
732 tcg_env <- getGblEnv ;
734 let { main_mod = case mainModIs dflags of {
735 Just mod -> mkModule mod ;
737 main_fn = case mainFunIs dflags of {
738 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
739 Nothing -> main_RDR_Unqual } } ;
741 check_main ghci_mode tcg_env main_mod main_fn
745 check_main ghci_mode tcg_env main_mod main_fn
747 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
751 = addErrCtxt mainCtxt $
752 do { mb_main <- lookupSrcOcc_maybe main_fn
753 -- Check that 'main' is in scope
754 -- It might be imported from another module!
756 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
760 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
761 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
762 -- :Main.main :: IO () = runMainIO main
764 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
767 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
768 main_bind = noLoc (VarBind root_main_id main_expr) }
770 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
772 tcg_dus = tcg_dus tcg_env
773 `plusDU` usesOnly (unitFV main_name)
774 -- Record the use of 'main', so that we don't
775 -- complain about it being defined but not used
779 mod = tcg_mod tcg_env
781 complain_no_main | ghci_mode == Interactive = return ()
782 | otherwise = failWithTc noMainMsg
783 -- In interactive mode, don't worry about the absence of 'main'
784 -- In other modes, fail altogether, so that we don't go on
785 -- and complain a second time when processing the export list.
787 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
788 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
789 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
792 %*********************************************************
796 %*********************************************************
800 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
801 setInteractiveContext hsc_env icxt thing_inside
803 -- Initialise the tcg_inst_env with instances
804 -- from all home modules. This mimics the more selective
805 -- call to hptInstances in tcRnModule
806 dfuns = hptInstances hsc_env (\mod -> True)
808 updGblEnv (\env -> env {
809 tcg_rdr_env = ic_rn_gbl_env icxt,
810 tcg_type_env = ic_type_env icxt,
811 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
813 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
815 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
822 -> InteractiveContext
824 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
825 -- The returned [Name] is the same as the input except for
826 -- ExprStmt, in which case the returned [Name] is [itName]
828 -- The returned TypecheckedHsExpr is of type IO [ () ],
829 -- a list of the bound values, coerced to ().
831 tcRnStmt hsc_env ictxt rdr_stmt
832 = initTcPrintErrors hsc_env iNTERACTIVE $
833 setInteractiveContext hsc_env ictxt $ do {
835 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
836 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
837 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
840 -- The real work is done here
841 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
842 zonked_expr <- zonkTopLExpr tc_expr ;
843 zonked_ids <- zonkTopBndrs bound_ids ;
845 -- None of the Ids should be of unboxed type, because we
846 -- cast them all to HValues in the end!
847 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
849 traceTc (text "tcs 1") ;
850 let { -- (a) Make all the bound ids "global" ids, now that
851 -- they're notionally top-level bindings. This is
852 -- important: otherwise when we come to compile an expression
853 -- using these ids later, the byte code generator will consider
854 -- the occurrences to be free rather than global.
856 -- (b) Tidy their types; this is important, because :info may
857 -- ask to look at them, and :info expects the things it looks
858 -- up to have tidy types
859 global_ids = map globaliseAndTidy zonked_ids ;
861 -- Update the interactive context
862 rn_env = ic_rn_local_env ictxt ;
863 type_env = ic_type_env ictxt ;
865 bound_names = map idName global_ids ;
866 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
868 -- Remove any shadowed bindings from the type_env;
869 -- they are inaccessible but might, I suppose, cause
870 -- a space leak if we leave them there
871 shadowed = [ n | name <- bound_names,
872 let rdr_name = mkRdrUnqual (nameOccName name),
873 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
875 filtered_type_env = delListFromNameEnv type_env shadowed ;
876 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
878 new_ic = ictxt { ic_rn_local_env = new_rn_env,
879 ic_type_env = new_type_env }
882 dumpOptTcRn Opt_D_dump_tc
883 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
884 text "Typechecked expr" <+> ppr zonked_expr]) ;
886 returnM (new_ic, bound_names, zonked_expr)
889 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
890 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
892 globaliseAndTidy :: Id -> Id
894 -- Give the Id a Global Name, and tidy its type
895 = setIdType (globaliseId VanillaGlobal id) tidy_type
897 tidy_type = tidyTopType (idType id)
900 Here is the grand plan, implemented in tcUserStmt
902 What you type The IO [HValue] that hscStmt returns
903 ------------- ------------------------------------
904 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
907 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
910 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
911 [NB: result not printed] bindings: [it]
913 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
914 result showable) bindings: [it]
916 expr (of non-IO type,
917 result not showable) ==> error
921 ---------------------------
922 type PlanResult = ([Id], LHsExpr Id)
923 type Plan = TcM PlanResult
925 runPlans :: [Plan] -> TcM PlanResult
926 -- Try the plans in order. If one fails (by raising an exn), try the next.
927 -- If one succeeds, take it.
928 runPlans [] = panic "runPlans"
930 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
933 mkPlan :: LStmt Name -> TcM PlanResult
934 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
935 = do { uniq <- newUnique -- is treated very specially
936 ; let fresh_it = itName uniq
937 the_bind = mkVarBind noSrcSpan fresh_it expr
938 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsIn (unitBag the_bind) []))
939 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
940 (HsVar bindIOName) noSyntaxExpr
941 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
942 (HsVar thenIOName) placeHolderType
945 -- [it <- e; print it] but not if it::()
947 -- [let it = e; print it]
948 ; runPlans [ -- Plan A
949 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
950 ; it_ty <- zonkTcType (idType it_id)
951 ; ifM (isUnitTy it_ty) failM
954 -- Plan B; a naked bind statment
955 tcGhciStmts [bind_stmt],
957 -- Plan C; check that the let-binding is typeable all by itself.
958 -- If not, fail; if so, try to print it.
959 -- The two-step process avoids getting two errors: one from
960 -- the expression itself, and one from the 'print it' part
961 -- This two-step story is very clunky, alas
962 do { checkNoErrs (tcGhciStmts [let_stmt])
963 --- checkNoErrs defeats the error recovery of let-bindings
964 ; tcGhciStmts [let_stmt, print_it] }
967 mkPlan stmt@(L loc (BindStmt {}))
968 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
969 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
970 (HsVar thenIOName) placeHolderType
972 -- [stmt; print v] but not if v::()
974 ; runPlans [do { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
975 ; v_ty <- zonkTcType (idType v_id)
976 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
984 ---------------------------
985 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
987 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
988 ret_id <- tcLookupId returnIOName ; -- return @ IO
990 io_ty = mkTyConApp ioTyCon [] ;
991 ret_ty = mkListTy unitTy ;
992 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
994 names = map unLoc (collectLStmtsBinders stmts) ;
996 -- mk_return builds the expression
997 -- returnIO @ [()] [coerce () x, .., coerce () z]
999 -- Despite the inconvenience of building the type applications etc,
1000 -- this *has* to be done in type-annotated post-typecheck form
1001 -- because we are going to return a list of *polymorphic* values
1002 -- coerced to type (). If we built a *source* stmt
1003 -- return [coerce x, ..., coerce z]
1004 -- then the type checker would instantiate x..z, and we wouldn't
1005 -- get their *polymorphic* values. (And we'd get ambiguity errs
1006 -- if they were overloaded, since they aren't applied to anything.)
1007 mk_return ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
1008 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1009 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
1013 -- OK, we're ready to typecheck the stmts
1014 traceTc (text "tcs 2") ;
1015 ((tc_stmts, ids), lie) <- getLIE $
1016 tcStmts DoExpr (tcDoStmt io_ty io_ret_ty) stmts $
1017 mappM tcLookupId names ;
1018 -- Look up the names right in the middle,
1019 -- where they will all be in scope
1021 -- Simplify the context
1022 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1023 -- checkNoErrs ensures that the plan fails if context redn fails
1025 return (ids, mkHsDictLet const_binds $
1026 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1031 tcRnExpr just finds the type of an expression
1035 -> InteractiveContext
1038 tcRnExpr hsc_env ictxt rdr_expr
1039 = initTcPrintErrors hsc_env iNTERACTIVE $
1040 setInteractiveContext hsc_env ictxt $ do {
1042 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1045 -- Now typecheck the expression;
1046 -- it might have a rank-2 type (e.g. :t runST)
1047 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1048 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1049 tcSimplifyInteractive lie_top ;
1050 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
1052 let { all_expr_ty = mkForAllTys qtvs' $
1053 mkFunTys (map idType dict_ids) $
1055 zonkTcType all_expr_ty
1058 smpl_doc = ptext SLIT("main expression")
1061 tcRnType just finds the kind of a type
1065 -> InteractiveContext
1068 tcRnType hsc_env ictxt rdr_type
1069 = initTcPrintErrors hsc_env iNTERACTIVE $
1070 setInteractiveContext hsc_env ictxt $ do {
1072 rn_type <- rnLHsType doc rdr_type ;
1075 -- Now kind-check the type
1076 (ty', kind) <- kcHsType rn_type ;
1080 doc = ptext SLIT("In GHCi input")
1086 %************************************************************************
1088 More GHCi stuff, to do with browsing and getting info
1090 %************************************************************************
1094 -- ASSUMES that the module is either in the HomePackageTable or is
1095 -- a package module with an interface on disk. If neither of these is
1096 -- true, then the result will be an error indicating the interface
1097 -- could not be found.
1098 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe NameSet)
1099 getModuleExports hsc_env mod
1100 = initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod)
1102 tcGetModuleExports :: Module -> TcM NameSet
1103 tcGetModuleExports mod = do
1104 iface <- load_iface mod
1105 loadOrphanModules (dep_orphs (mi_deps iface))
1106 -- Load any orphan-module interfaces,
1107 -- so their instances are visible
1108 ifaceExportNames (mi_exports iface)
1110 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
1112 doc = ptext SLIT("context for compiling statements")
1115 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1116 tcRnLookupRdrName hsc_env rdr_name
1117 = initTcPrintErrors hsc_env iNTERACTIVE $
1118 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1119 lookup_rdr_name rdr_name
1121 lookup_rdr_name rdr_name = do {
1122 -- If the identifier is a constructor (begins with an
1123 -- upper-case letter), then we need to consider both
1124 -- constructor and type class identifiers.
1125 let { rdr_names = dataTcOccs rdr_name } ;
1127 -- results :: [Either Messages Name]
1128 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1130 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1131 -- The successful lookups will be (Just name)
1132 let { (warns_s, good_names) = unzip [ (msgs, name)
1133 | (msgs, Just name) <- results] ;
1134 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1136 -- Fail if nothing good happened, else add warnings
1137 if null good_names then
1138 -- No lookup succeeded, so
1139 -- pick the first error message and report it
1140 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1141 -- while the other is "X is not in scope",
1142 -- we definitely want the former; but we might pick the latter
1143 do { addMessages (head errs_s) ; failM }
1144 else -- Add deprecation warnings
1145 mapM_ addMessages warns_s ;
1151 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1152 tcRnLookupName hsc_env name
1153 = initTcPrintErrors hsc_env iNTERACTIVE $
1154 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1158 tcRnGetInfo :: HscEnv
1160 -> IO (Maybe (TyThing, Fixity, [Instance]))
1162 -- Used to implemnent :info in GHCi
1164 -- Look up a RdrName and return all the TyThings it might be
1165 -- A capitalised RdrName is given to us in the DataName namespace,
1166 -- but we want to treat it as *both* a data constructor
1167 -- *and* as a type or class constructor;
1168 -- hence the call to dataTcOccs, and we return up to two results
1169 tcRnGetInfo hsc_env name
1170 = initTcPrintErrors hsc_env iNTERACTIVE $
1171 let ictxt = hsc_IC hsc_env in
1172 setInteractiveContext hsc_env ictxt $ do
1174 -- Load the interface for all unqualified types and classes
1175 -- That way we will find all the instance declarations
1176 -- (Packages have not orphan modules, and we assume that
1177 -- in the home package all relevant modules are loaded.)
1178 loadUnqualIfaces ictxt
1180 thing <- tcLookupGlobal name
1181 fixity <- lookupFixityRn name
1182 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1183 return (thing, fixity, ispecs)
1186 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1187 -- Filter the instances by the ones whose tycons (or clases resp)
1188 -- are in scope unqualified. Otherwise we list a whole lot too many!
1189 lookupInsts print_unqual (AClass cls)
1190 = do { inst_envs <- tcGetInstEnvs
1192 | ispec <- classInstances inst_envs cls
1193 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1195 lookupInsts print_unqual (ATyCon tc)
1196 = do { eps <- getEps -- Load all instances for all classes that are
1197 -- in the type environment (which are all the ones
1198 -- we've seen in any interface file so far)
1199 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1201 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1202 , let dfun = instanceDFunId ispec
1204 , plausibleDFun print_unqual dfun ] }
1206 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1207 tc_name = tyConName tc
1209 lookupInsts print_unqual other = return []
1211 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1212 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1214 ok name | isBuiltInSyntax name = True
1215 | isExternalName name = print_unqual (nameModule name) (nameOccName name)
1218 loadUnqualIfaces :: InteractiveContext -> TcM ()
1219 -- Load the home module for everything that is in scope unqualified
1220 -- This is so that we can accurately report the instances for
1222 loadUnqualIfaces ictxt
1224 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1226 unqual_mods = [ nameModule name
1227 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1228 let name = gre_name gre,
1229 isTcOcc (nameOccName name), -- Types and classes only
1230 unQualOK gre ] -- In scope unqualified
1231 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1235 %************************************************************************
1239 %************************************************************************
1242 rnDump :: SDoc -> TcRn ()
1243 -- Dump, with a banner, if -ddump-rn
1244 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1246 tcDump :: TcGblEnv -> TcRn ()
1248 = do { dflags <- getDOpts ;
1250 -- Dump short output if -ddump-types or -ddump-tc
1251 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1252 (dumpTcRn short_dump) ;
1254 -- Dump bindings if -ddump-tc
1255 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1258 short_dump = pprTcGblEnv env
1259 full_dump = pprLHsBinds (tcg_binds env)
1260 -- NB: foreign x-d's have undefined's in their types;
1261 -- hence can't show the tc_fords
1264 = do { dflags <- getDOpts ;
1265 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1266 (dumpTcRn (pprModGuts mod_guts)) ;
1268 -- Dump bindings if -ddump-tc
1269 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1271 full_dump = pprCoreBindings (mg_binds mod_guts)
1273 -- It's unpleasant having both pprModGuts and pprModDetails here
1274 pprTcGblEnv :: TcGblEnv -> SDoc
1275 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1276 tcg_insts = dfun_ids,
1278 tcg_imports = imports })
1279 = vcat [ ppr_types dfun_ids type_env
1280 , ppr_insts dfun_ids
1281 , vcat (map ppr rules)
1282 , ppr_gen_tycons (typeEnvTyCons type_env)
1283 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1284 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1286 pprModGuts :: ModGuts -> SDoc
1287 pprModGuts (ModGuts { mg_types = type_env,
1289 = vcat [ ppr_types [] type_env,
1293 ppr_types :: [Instance] -> TypeEnv -> SDoc
1294 ppr_types ispecs type_env
1295 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1297 dfun_ids = map instanceDFunId ispecs
1298 ids = [id | id <- typeEnvIds type_env, want_sig id]
1299 want_sig id | opt_PprStyle_Debug = True
1300 | otherwise = isLocalId id &&
1301 isExternalName (idName id) &&
1302 not (id `elem` dfun_ids)
1303 -- isLocalId ignores data constructors, records selectors etc.
1304 -- The isExternalName ignores local dictionary and method bindings
1305 -- that the type checker has invented. Top-level user-defined things
1306 -- have External names.
1308 ppr_insts :: [Instance] -> SDoc
1309 ppr_insts [] = empty
1310 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1312 ppr_sigs :: [Var] -> SDoc
1314 -- Print type signatures; sort by OccName
1315 = vcat (map ppr_sig (sortLe le_sig ids))
1317 le_sig id1 id2 = getOccName id1 <= getOccName id2
1318 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1320 ppr_rules :: [CoreRule] -> SDoc
1321 ppr_rules [] = empty
1322 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1323 nest 4 (pprRules rs),
1326 ppr_gen_tycons [] = empty
1327 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1328 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]