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 emptyGroup, appendGroups,
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(..), HsBindGroup(..),
85 LStmt, LHsExpr, LHsType, mkVarBind,
86 collectLStmtsBinders, collectLStmtBinders, nlVarPat,
87 placeHolderType, noSyntaxExpr )
88 import RdrName ( GlobalRdrElt(..), globalRdrEnvElts,
89 unQualOK, lookupLocalRdrEnv, extendLocalRdrEnv )
90 import RnSource ( addTcgDUs )
91 import TcHsSyn ( mkHsLet, zonkTopLExpr, zonkTopBndrs )
92 import TcHsType ( kcHsType )
93 import TcMType ( zonkTcType, zonkQuantifiedTyVar )
94 import TcMatches ( tcStmts, tcDoStmt )
95 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
96 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType, isTauTy,
97 isUnLiftedType, tyClsNamesOfDFunHead, tyClsNamesOfType, isUnitTy )
98 import TcEnv ( tcLookupTyCon, tcLookupId, tcLookupGlobal )
99 import RnTypes ( rnLHsType )
100 import Inst ( tcGetInstEnvs )
101 import InstEnv ( classInstances, instEnvElts )
102 import RnExpr ( rnStmts, rnLExpr )
103 import LoadIface ( loadSrcInterface, loadSysInterface )
104 import IfaceEnv ( ifaceExportNames )
105 import Module ( moduleSetElts, mkModuleSet )
106 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
107 import Id ( setIdType )
108 import MkId ( unsafeCoerceId )
109 import TyCon ( tyConName )
110 import TysWiredIn ( mkListTy, unitTy )
111 import IdInfo ( GlobalIdDetails(..) )
113 import Var ( globaliseId )
114 import Name ( nameOccName, nameModule, isBuiltInSyntax )
115 import OccName ( isTcOcc )
116 import NameEnv ( delListFromNameEnv )
117 import PrelNames ( iNTERACTIVE, ioTyConName, printName, itName,
118 bindIOName, thenIOName, returnIOName )
119 import HscTypes ( InteractiveContext(..),
120 ModIface(..), icPrintUnqual,
122 import BasicTypes ( RecFlag(..), Fixity )
123 import SrcLoc ( unLoc, noSrcSpan )
126 import FastString ( mkFastString )
127 import Maybes ( MaybeErr(..) )
128 import Util ( sortLe )
129 import Bag ( unionBags, snocBag, emptyBag, unitBag, unionManyBags )
131 import Maybe ( isJust )
136 %************************************************************************
138 Typecheck and rename a module
140 %************************************************************************
146 -> Bool -- True <=> save renamed syntax
147 -> Located (HsModule RdrName)
148 -> IO (Messages, Maybe TcGblEnv)
150 tcRnModule hsc_env hsc_src save_rn_decls
151 (L loc (HsModule maybe_mod export_ies
152 import_decls local_decls mod_deprec))
153 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
155 let { this_mod = case maybe_mod of
156 Nothing -> mAIN -- 'module M where' is omitted
157 Just (L _ mod) -> mod } ; -- The normal case
159 initTc hsc_env hsc_src this_mod $
162 -- Deal with imports; sets tcg_rdr_env, tcg_imports
163 (rdr_env, imports) <- rnImports import_decls ;
165 let { dep_mods :: ModuleEnv (Module, IsBootInterface)
166 ; dep_mods = imp_dep_mods imports
168 -- We want instance declarations from all home-package
169 -- modules below this one, including boot modules, except
170 -- ourselves. The 'except ourselves' is so that we don't
171 -- get the instances from this module's hs-boot file
172 ; want_instances :: Module -> Bool
173 ; want_instances mod = mod `elemModuleEnv` dep_mods
175 ; home_insts = hptInstances hsc_env want_instances
178 -- Record boot-file info in the EPS, so that it's
179 -- visible to loadHiBootInterface in tcRnSrcDecls,
180 -- and any other incrementally-performed imports
181 updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
183 checkConflicts imports this_mod $ do {
185 -- Update the gbl env
187 gbl { tcg_rdr_env = rdr_env,
188 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts,
189 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
190 tcg_rn_decls = if save_rn_decls then
196 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
197 -- Fail if there are any errors so far
198 -- The error printing (if needed) takes advantage
199 -- of the tcg_env we have now set
202 -- Load any orphan-module interfaces, so that
203 -- their rules and instance decls will be found
204 loadOrphanModules (imp_orphs imports) ;
206 traceRn (text "rn1a") ;
207 -- Rename and type check the declarations
208 tcg_env <- if isHsBoot hsc_src then
209 tcRnHsBootDecls local_decls
211 tcRnSrcDecls local_decls ;
212 setGblEnv tcg_env $ do {
214 traceRn (text "rn3") ;
216 -- Report the use of any deprecated things
217 -- We do this before processsing the export list so
218 -- that we don't bleat about re-exporting a deprecated
219 -- thing (especially via 'module Foo' export item)
220 -- Only uses in the body of the module are complained about
221 reportDeprecations tcg_env ;
223 -- Process the export list
224 exports <- rnExports (isJust maybe_mod) export_ies ;
226 -- Check whether the entire module is deprecated
227 -- This happens only once per module
228 let { mod_deprecs = checkModDeprec mod_deprec } ;
230 -- Add exports and deprecations to envt
231 let { final_env = tcg_env { tcg_exports = exports,
232 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
233 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
235 -- A module deprecation over-rides the earlier ones
238 -- Report unused names
239 reportUnusedNames export_ies final_env ;
241 -- Dump output and return
247 -- The program is not allowed to contain two modules with the same
248 -- name, and we check for that here. It could happen if the home package
249 -- contains a module that is also present in an external package, for example.
250 checkConflicts imports this_mod and_then = do
253 dep_mods = this_mod : map fst (moduleEnvElts (imp_dep_mods imports))
254 -- don't forget to include the current module!
256 mb_dep_pkgs = checkForPackageConflicts
257 dflags dep_mods (imp_dep_pkgs imports)
263 updGblEnv (\gbl -> gbl{ tcg_home_mods = mkHomeModules dep_mods })
268 %************************************************************************
270 Type-checking external-core modules
272 %************************************************************************
275 tcRnExtCore :: HscEnv
277 -> IO (Messages, Maybe ModGuts)
278 -- Nothing => some error occurred
280 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
281 -- The decls are IfaceDecls; all names are original names
282 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
284 initTc hsc_env ExtCoreFile this_mod $ do {
286 let { ldecls = map noLoc decls } ;
288 -- Deal with the type declarations; first bring their stuff
289 -- into scope, then rname them, then type check them
290 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
292 setGblEnv tcg_env $ do {
294 rn_decls <- rnTyClDecls ldecls ;
297 -- Dump trace of renaming part
298 rnDump (ppr rn_decls) ;
300 -- Typecheck them all together so that
301 -- any mutually recursive types are done right
302 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
303 -- Make the new type env available to stuff slurped from interface files
305 setGblEnv tcg_env $ do {
307 -- Now the core bindings
308 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
312 bndrs = bindersOfBinds core_binds ;
313 my_exports = mkNameSet (map idName bndrs) ;
314 -- ToDo: export the data types also?
316 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
318 mod_guts = ModGuts { mg_module = this_mod,
320 mg_usages = [], -- ToDo: compute usage
321 mg_dir_imps = [], -- ??
322 mg_deps = noDependencies, -- ??
323 mg_home_mods = mkHomeModules [], -- ?? wrong!!
324 mg_exports = my_exports,
325 mg_types = final_type_env,
326 mg_insts = tcg_insts tcg_env,
328 mg_binds = core_binds,
331 mg_rdr_env = emptyGlobalRdrEnv,
332 mg_fix_env = emptyFixityEnv,
333 mg_deprecs = NoDeprecs,
337 tcCoreDump mod_guts ;
342 mkFakeGroup decls -- Rather clumsy; lots of unused fields
343 = HsGroup { hs_tyclds = decls, -- This is the one we want
344 hs_valds = [], hs_fords = [],
345 hs_instds = [], hs_fixds = [], hs_depds = [],
346 hs_ruleds = [], hs_defds = [] }
350 %************************************************************************
352 Type-checking the top level of a module
354 %************************************************************************
357 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
358 -- Returns the variables free in the decls
359 -- Reason: solely to report unused imports and bindings
361 = do { -- Load the hi-boot interface for this module, if any
362 -- We do this now so that the boot_names can be passed
363 -- to tcTyAndClassDecls, because the boot_names are
364 -- automatically considered to be loop breakers
366 boot_iface <- tcHiBootIface mod ;
368 -- Do all the declarations
369 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_iface decls) ;
371 -- tcSimplifyTop deals with constant or ambiguous InstIds.
372 -- How could there be ambiguous ones? They can only arise if a
373 -- top-level decl falls under the monomorphism
374 -- restriction, and no subsequent decl instantiates its
375 -- type. (Usually, ambiguous type variables are resolved
376 -- during the generalisation step.)
377 traceTc (text "Tc8") ;
378 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
379 -- Setting the global env exposes the instances to tcSimplifyTop
380 -- Setting the local env exposes the local Ids to tcSimplifyTop,
381 -- so that we get better error messages (monomorphism restriction)
383 -- Backsubstitution. This must be done last.
384 -- Even tcSimplifyTop may do some unification.
385 traceTc (text "Tc9") ;
386 let { (tcg_env, _) = tc_envs ;
387 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
388 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
390 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
393 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
394 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
397 tcg_fords = fords' } } ;
399 -- Make the new type env available to stuff slurped from interface files
400 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
402 -- Compare the hi-boot iface (if any) with the real thing
403 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
405 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
408 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
409 -- Loops around dealing with each top level inter-splice group
410 -- in turn, until it's dealt with the entire module
411 tc_rn_src_decls boot_details ds
412 = do { let { (first_group, group_tail) = findSplice ds } ;
413 -- If ds is [] we get ([], Nothing)
415 -- Type check the decls up to, but not including, the first splice
416 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_details first_group ;
418 -- Bale out if errors; for example, error recovery when checking
419 -- the RHS of 'main' can mean that 'main' is not in the envt for
420 -- the subsequent checkMain test
425 -- If there is no splice, we're nearly done
427 Nothing -> do { -- Last thing: check for `main'
428 tcg_env <- checkMain ;
429 return (tcg_env, tcl_env)
432 -- If there's a splice, we must carry on
433 Just (SpliceDecl splice_expr, rest_ds) -> do {
435 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
438 -- Rename the splice expression, and get its supporting decls
439 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
440 failIfErrsM ; -- Don't typecheck if renaming failed
442 -- Execute the splice
443 spliced_decls <- tcSpliceDecls rn_splice_expr ;
445 -- Glue them on the front of the remaining decls and loop
446 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
447 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
452 %************************************************************************
454 Compiling hs-boot source files, and
455 comparing the hi-boot interface with the real thing
457 %************************************************************************
460 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
461 tcRnHsBootDecls decls
462 = do { let { (first_group, group_tail) = findSplice decls }
465 Just stuff -> spliceInHsBootErr stuff
468 -- Rename the declarations
469 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
470 ; setGblEnv tcg_env $ do {
472 -- Todo: check no foreign decls, no rules, no default decls
474 -- Typecheck type/class decls
475 ; traceTc (text "Tc2")
476 ; let tycl_decls = hs_tyclds rn_group
477 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
478 ; setGblEnv tcg_env $ do {
480 -- Typecheck instance decls
481 ; traceTc (text "Tc3")
482 ; (tcg_env, inst_infos, _binds) <- tcInstDecls1 tycl_decls (hs_instds rn_group)
483 ; setGblEnv tcg_env $ do {
485 -- Typecheck value declarations
486 ; traceTc (text "Tc5")
487 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
490 -- No simplification or zonking to do
491 ; traceTc (text "Tc7a")
492 ; gbl_env <- getGblEnv
494 -- Make the final type-env
495 -- Include the dfun_ids so that their type sigs get
496 -- are written into the interface file
497 ; let { type_env0 = tcg_type_env gbl_env
498 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
499 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
500 ; dfun_ids = map iDFunId inst_infos }
501 ; return (gbl_env { tcg_type_env = type_env2 })
504 spliceInHsBootErr (SpliceDecl (L loc _), _)
505 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
508 Once we've typechecked the body of the module, we want to compare what
509 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
512 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
513 -- Compare the hi-boot file for this module (if there is one)
514 -- with the type environment we've just come up with
515 -- In the common case where there is no hi-boot file, the list
516 -- of boot_names is empty.
518 -- The bindings we return give bindings for the dfuns defined in the
519 -- hs-boot file, such as $fbEqT = $fEqT
522 (TcGblEnv { tcg_insts = local_insts, tcg_type_env = local_type_env })
523 (ModDetails { md_insts = boot_insts, md_types = boot_type_env })
524 = do { mapM_ check_one (typeEnvElts boot_type_env)
525 ; dfun_binds <- mapM check_inst boot_insts
526 ; return (unionManyBags dfun_binds) }
532 = case lookupTypeEnv local_type_env name of
533 Nothing -> addErrTc (missingBootThing boot_thing)
534 Just real_thing -> check_thing boot_thing real_thing
536 name = getName boot_thing
538 no_check name = isWiredInName name -- No checking for wired-in names. In particular,
539 -- 'error' is handled by a rather gross hack
540 -- (see comments in GHC.Err.hs-boot)
541 || name `elem` dfun_names
542 dfun_names = map getName boot_insts
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 = mkExportedLocalId (idName boot_dfun) boot_inst_ty
556 check_thing (ATyCon boot_tc) (ATyCon real_tc)
557 | isSynTyCon boot_tc && isSynTyCon real_tc,
558 defn1 `tcEqType` substTyWith tvs2 (mkTyVarTys tvs1) defn2
561 | tyConKind boot_tc == tyConKind real_tc
564 (tvs1, defn1) = getSynTyConDefn boot_tc
565 (tvs2, defn2) = getSynTyConDefn boot_tc
567 check_thing (AnId boot_id) (AnId real_id)
568 | idType boot_id `tcEqType` idType real_id
571 check_thing (ADataCon dc1) (ADataCon dc2)
572 | idType (dataConWrapId dc1) `tcEqType` idType (dataConWrapId dc2)
575 -- Can't declare a class in a hi-boot file
577 check_thing boot_thing real_thing -- Default case; failure
578 = addErrAt (srcLocSpan (getSrcLoc real_thing))
579 (bootMisMatch real_thing)
582 missingBootThing thing
583 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
585 = ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file")
588 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
592 %************************************************************************
594 Type-checking the top level of a module
596 %************************************************************************
598 tcRnGroup takes a bunch of top-level source-code declarations, and
600 * gets supporting declarations from interface files
603 * and augments the TcGblEnv with the results
605 In Template Haskell it may be called repeatedly for each group of
606 declarations. It expects there to be an incoming TcGblEnv in the
607 monad; it augments it and returns the new TcGblEnv.
610 tcRnGroup :: ModDetails -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
611 -- Returns the variables free in the decls, for unused-binding reporting
612 tcRnGroup boot_details decls
613 = do { -- Rename the declarations
614 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
615 setGblEnv tcg_env $ do {
617 -- Typecheck the declarations
618 tcTopSrcDecls boot_details rn_decls
621 ------------------------------------------------
622 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
624 = do { -- Bring top level binders into scope
625 tcg_env <- importsFromLocalDecls group ;
626 setGblEnv tcg_env $ do {
628 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
630 -- Rename the source decls
631 (tcg_env, rn_decls) <- rnSrcDecls group ;
634 -- save the renamed syntax, if we want it
636 | Just grp <- tcg_rn_decls tcg_env
637 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
641 -- Dump trace of renaming part
642 rnDump (ppr rn_decls) ;
644 return (tcg_env', rn_decls)
647 ------------------------------------------------
648 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
649 tcTopSrcDecls boot_details
650 (HsGroup { hs_tyclds = tycl_decls,
651 hs_instds = inst_decls,
652 hs_fords = foreign_decls,
653 hs_defds = default_decls,
654 hs_ruleds = rule_decls,
655 hs_valds = val_binds })
656 = do { -- Type-check the type and class decls, and all imported decls
657 -- The latter come in via tycl_decls
658 traceTc (text "Tc2") ;
660 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
661 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
662 -- an error we'd better stop now, to avoid a cascade
664 -- Make these type and class decls available to stuff slurped from interface files
665 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
668 setGblEnv tcg_env $ do {
669 -- Source-language instances, including derivings,
670 -- and import the supporting declarations
671 traceTc (text "Tc3") ;
672 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
673 setGblEnv tcg_env $ do {
675 -- Foreign import declarations next. No zonking necessary
676 -- here; we can tuck them straight into the global environment.
677 traceTc (text "Tc4") ;
678 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
679 tcExtendGlobalValEnv fi_ids $ do {
681 -- Default declarations
682 traceTc (text "Tc4a") ;
683 default_tys <- tcDefaults default_decls ;
684 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
686 -- Value declarations next
687 -- We also typecheck any extra binds that came out
688 -- of the "deriving" process (deriv_binds)
689 traceTc (text "Tc5") ;
690 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
691 setLclTypeEnv tcl_env $ do {
693 -- Second pass over class and instance declarations,
694 traceTc (text "Tc6") ;
695 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
696 showLIE (text "after instDecls2") ;
699 -- They need to be zonked, so we return them
700 traceTc (text "Tc7") ;
701 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
704 rules <- tcRules rule_decls ;
707 traceTc (text "Tc7a") ;
708 tcg_env <- getGblEnv ;
709 let { all_binds = tc_val_binds `unionBags`
710 inst_binds `unionBags`
713 -- Extend the GblEnv with the (as yet un-zonked)
714 -- bindings, rules, foreign decls
715 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
716 tcg_rules = tcg_rules tcg_env ++ rules,
717 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
718 return (tcg_env', tcl_env)
723 %************************************************************************
727 %************************************************************************
730 checkMain :: TcM TcGblEnv
731 -- If we are in module Main, check that 'main' is defined.
733 = do { ghci_mode <- getGhciMode ;
734 tcg_env <- getGblEnv ;
736 let { main_mod = case mainModIs dflags of {
737 Just mod -> mkModule mod ;
739 main_fn = case mainFunIs dflags of {
740 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
741 Nothing -> main_RDR_Unqual } } ;
743 check_main ghci_mode tcg_env main_mod main_fn
747 check_main ghci_mode tcg_env main_mod main_fn
749 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
753 = addErrCtxt mainCtxt $
754 do { mb_main <- lookupSrcOcc_maybe main_fn
755 -- Check that 'main' is in scope
756 -- It might be imported from another module!
758 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
762 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
763 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
764 -- :Main.main :: IO () = runMainIO main
766 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
769 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
770 main_bind = noLoc (VarBind root_main_id main_expr) }
772 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
774 tcg_dus = tcg_dus tcg_env
775 `plusDU` usesOnly (unitFV main_name)
776 -- Record the use of 'main', so that we don't
777 -- complain about it being defined but not used
781 mod = tcg_mod tcg_env
783 complain_no_main | ghci_mode == Interactive = return ()
784 | otherwise = failWithTc noMainMsg
785 -- In interactive mode, don't worry about the absence of 'main'
786 -- In other modes, fail altogether, so that we don't go on
787 -- and complain a second time when processing the export list.
789 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
790 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
791 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
794 %*********************************************************
798 %*********************************************************
802 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
803 setInteractiveContext hsc_env icxt thing_inside
805 -- Initialise the tcg_inst_env with instances
806 -- from all home modules. This mimics the more selective
807 -- call to hptInstances in tcRnModule
808 dfuns = hptInstances hsc_env (\mod -> True)
810 updGblEnv (\env -> env {
811 tcg_rdr_env = ic_rn_gbl_env icxt,
812 tcg_type_env = ic_type_env icxt,
813 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
815 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
817 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
824 -> InteractiveContext
826 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
827 -- The returned [Name] is the same as the input except for
828 -- ExprStmt, in which case the returned [Name] is [itName]
830 -- The returned TypecheckedHsExpr is of type IO [ () ],
831 -- a list of the bound values, coerced to ().
833 tcRnStmt hsc_env ictxt rdr_stmt
834 = initTcPrintErrors hsc_env iNTERACTIVE $
835 setInteractiveContext hsc_env ictxt $ do {
837 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
838 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
839 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
842 -- The real work is done here
843 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
844 zonked_expr <- zonkTopLExpr tc_expr ;
845 zonked_ids <- zonkTopBndrs bound_ids ;
847 -- None of the Ids should be of unboxed type, because we
848 -- cast them all to HValues in the end!
849 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
851 traceTc (text "tcs 1") ;
852 let { -- (a) Make all the bound ids "global" ids, now that
853 -- they're notionally top-level bindings. This is
854 -- important: otherwise when we come to compile an expression
855 -- using these ids later, the byte code generator will consider
856 -- the occurrences to be free rather than global.
858 -- (b) Tidy their types; this is important, because :info may
859 -- ask to look at them, and :info expects the things it looks
860 -- up to have tidy types
861 global_ids = map globaliseAndTidy zonked_ids ;
863 -- Update the interactive context
864 rn_env = ic_rn_local_env ictxt ;
865 type_env = ic_type_env ictxt ;
867 bound_names = map idName global_ids ;
868 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
870 -- Remove any shadowed bindings from the type_env;
871 -- they are inaccessible but might, I suppose, cause
872 -- a space leak if we leave them there
873 shadowed = [ n | name <- bound_names,
874 let rdr_name = mkRdrUnqual (nameOccName name),
875 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
877 filtered_type_env = delListFromNameEnv type_env shadowed ;
878 new_type_env = extendTypeEnvWithIds filtered_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 = 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 = mkVarBind noSrcSpan fresh_it expr
940 let_stmt = L loc $ LetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive]
941 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
942 (HsVar bindIOName) noSyntaxExpr
943 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
944 (HsVar thenIOName) placeHolderType
947 -- [it <- e; print it] but not if it::()
949 -- [let it = e; print it]
950 ; runPlans [ -- Plan A
951 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
952 ; it_ty <- zonkTcType (idType it_id)
953 ; ifM (isUnitTy it_ty) failM
956 -- Plan B; a naked bind statment
957 tcGhciStmts [bind_stmt],
959 -- Plan C; check that the let-binding is typeable all by itself.
960 -- If not, fail; if so, try to print it.
961 -- The two-step process avoids getting two errors: one from
962 -- the expression itself, and one from the 'print it' part
963 -- This two-step story is very clunky, alas
964 do { checkNoErrs (tcGhciStmts [let_stmt])
965 --- checkNoErrs defeats the error recovery of let-bindings
966 ; tcGhciStmts [let_stmt, print_it] }
969 mkPlan stmt@(L loc (BindStmt {}))
970 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
971 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
972 (HsVar thenIOName) placeHolderType
974 -- [stmt; print v] but not if v::()
976 ; runPlans [do { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
977 ; v_ty <- zonkTcType (idType v_id)
978 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
986 ---------------------------
987 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
989 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
990 ret_id <- tcLookupId returnIOName ; -- return @ IO
992 io_ty = mkTyConApp ioTyCon [] ;
993 ret_ty = mkListTy unitTy ;
994 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
996 names = map unLoc (collectLStmtsBinders stmts) ;
998 -- mk_return builds the expression
999 -- returnIO @ [()] [coerce () x, .., coerce () z]
1001 -- Despite the inconvenience of building the type applications etc,
1002 -- this *has* to be done in type-annotated post-typecheck form
1003 -- because we are going to return a list of *polymorphic* values
1004 -- coerced to type (). If we built a *source* stmt
1005 -- return [coerce x, ..., coerce z]
1006 -- then the type checker would instantiate x..z, and we wouldn't
1007 -- get their *polymorphic* values. (And we'd get ambiguity errs
1008 -- if they were overloaded, since they aren't applied to anything.)
1009 mk_return ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
1010 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1011 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
1015 -- OK, we're ready to typecheck the stmts
1016 traceTc (text "tcs 2") ;
1017 ((tc_stmts, ids), lie) <- getLIE $
1018 tcStmts DoExpr (tcDoStmt io_ty io_ret_ty) stmts $
1019 mappM tcLookupId names ;
1020 -- Look up the names right in the middle,
1021 -- where they will all be in scope
1023 -- Simplify the context
1024 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1025 -- checkNoErrs ensures that the plan fails if context redn fails
1027 return (ids, mkHsLet const_binds $
1028 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1033 tcRnExpr just finds the type of an expression
1037 -> InteractiveContext
1040 tcRnExpr hsc_env ictxt rdr_expr
1041 = initTcPrintErrors hsc_env iNTERACTIVE $
1042 setInteractiveContext hsc_env ictxt $ do {
1044 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1047 -- Now typecheck the expression;
1048 -- it might have a rank-2 type (e.g. :t runST)
1049 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1050 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1051 tcSimplifyInteractive lie_top ;
1052 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
1054 let { all_expr_ty = mkForAllTys qtvs' $
1055 mkFunTys (map idType dict_ids) $
1057 zonkTcType all_expr_ty
1060 smpl_doc = ptext SLIT("main expression")
1063 tcRnType just finds the kind of a type
1067 -> InteractiveContext
1070 tcRnType hsc_env ictxt rdr_type
1071 = initTcPrintErrors hsc_env iNTERACTIVE $
1072 setInteractiveContext hsc_env ictxt $ do {
1074 rn_type <- rnLHsType doc rdr_type ;
1077 -- Now kind-check the type
1078 (ty', kind) <- kcHsType rn_type ;
1082 doc = ptext SLIT("In GHCi input")
1088 %************************************************************************
1090 More GHCi stuff, to do with browsing and getting info
1092 %************************************************************************
1096 -- ASSUMES that the module is either in the HomePackageTable or is
1097 -- a package module with an interface on disk. If neither of these is
1098 -- true, then the result will be an error indicating the interface
1099 -- could not be found.
1100 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe NameSet)
1101 getModuleExports hsc_env mod
1102 = initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod)
1104 tcGetModuleExports :: Module -> TcM NameSet
1105 tcGetModuleExports mod = do
1106 iface <- load_iface mod
1107 loadOrphanModules (dep_orphs (mi_deps iface))
1108 -- Load any orphan-module interfaces,
1109 -- so their instances are visible
1110 ifaceExportNames (mi_exports iface)
1112 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
1114 doc = ptext SLIT("context for compiling statements")
1117 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1118 tcRnLookupRdrName hsc_env rdr_name
1119 = initTcPrintErrors hsc_env iNTERACTIVE $
1120 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1121 lookup_rdr_name rdr_name
1123 lookup_rdr_name rdr_name = do {
1124 -- If the identifier is a constructor (begins with an
1125 -- upper-case letter), then we need to consider both
1126 -- constructor and type class identifiers.
1127 let { rdr_names = dataTcOccs rdr_name } ;
1129 -- results :: [Either Messages Name]
1130 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1132 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1133 -- The successful lookups will be (Just name)
1134 let { (warns_s, good_names) = unzip [ (msgs, name)
1135 | (msgs, Just name) <- results] ;
1136 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1138 -- Fail if nothing good happened, else add warnings
1139 if null good_names then
1140 -- No lookup succeeded, so
1141 -- pick the first error message and report it
1142 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1143 -- while the other is "X is not in scope",
1144 -- we definitely want the former; but we might pick the latter
1145 do { addMessages (head errs_s) ; failM }
1146 else -- Add deprecation warnings
1147 mapM_ addMessages warns_s ;
1153 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1154 tcRnLookupName hsc_env name
1155 = initTcPrintErrors hsc_env iNTERACTIVE $
1156 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1160 tcRnGetInfo :: HscEnv
1162 -> IO (Maybe (TyThing, Fixity, [Instance]))
1164 -- Used to implemnent :info in GHCi
1166 -- Look up a RdrName and return all the TyThings it might be
1167 -- A capitalised RdrName is given to us in the DataName namespace,
1168 -- but we want to treat it as *both* a data constructor
1169 -- *and* as a type or class constructor;
1170 -- hence the call to dataTcOccs, and we return up to two results
1171 tcRnGetInfo hsc_env name
1172 = initTcPrintErrors hsc_env iNTERACTIVE $
1173 let ictxt = hsc_IC hsc_env in
1174 setInteractiveContext hsc_env ictxt $ do
1176 -- Load the interface for all unqualified types and classes
1177 -- That way we will find all the instance declarations
1178 -- (Packages have not orphan modules, and we assume that
1179 -- in the home package all relevant modules are loaded.)
1180 loadUnqualIfaces ictxt
1182 thing <- tcLookupGlobal name
1183 fixity <- lookupFixityRn name
1184 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1185 return (thing, fixity, ispecs)
1188 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1189 -- Filter the instances by the ones whose tycons (or clases resp)
1190 -- are in scope unqualified. Otherwise we list a whole lot too many!
1191 lookupInsts print_unqual (AClass cls)
1192 = do { inst_envs <- tcGetInstEnvs
1194 | ispec <- classInstances inst_envs cls
1195 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1197 lookupInsts print_unqual (ATyCon tc)
1198 = do { eps <- getEps -- Load all instances for all classes that are
1199 -- in the type environment (which are all the ones
1200 -- we've seen in any interface file so far)
1201 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1203 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1204 , let dfun = instanceDFunId ispec
1206 , plausibleDFun print_unqual dfun ] }
1208 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1209 tc_name = tyConName tc
1211 lookupInsts print_unqual other = return []
1213 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1214 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1216 ok name | isBuiltInSyntax name = True
1217 | isExternalName name = print_unqual (nameModule name) (nameOccName name)
1220 loadUnqualIfaces :: InteractiveContext -> TcM ()
1221 -- Load the home module for everything that is in scope unqualified
1222 -- This is so that we can accurately report the instances for
1224 loadUnqualIfaces ictxt
1226 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1228 unqual_mods = [ nameModule name
1229 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1230 let name = gre_name gre,
1231 isTcOcc (nameOccName name), -- Types and classes only
1232 unQualOK gre ] -- In scope unqualified
1233 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1237 %************************************************************************
1241 %************************************************************************
1244 rnDump :: SDoc -> TcRn ()
1245 -- Dump, with a banner, if -ddump-rn
1246 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1248 tcDump :: TcGblEnv -> TcRn ()
1250 = do { dflags <- getDOpts ;
1252 -- Dump short output if -ddump-types or -ddump-tc
1253 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1254 (dumpTcRn short_dump) ;
1256 -- Dump bindings if -ddump-tc
1257 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1260 short_dump = pprTcGblEnv env
1261 full_dump = pprLHsBinds (tcg_binds env)
1262 -- NB: foreign x-d's have undefined's in their types;
1263 -- hence can't show the tc_fords
1266 = do { dflags <- getDOpts ;
1267 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1268 (dumpTcRn (pprModGuts mod_guts)) ;
1270 -- Dump bindings if -ddump-tc
1271 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1273 full_dump = pprCoreBindings (mg_binds mod_guts)
1275 -- It's unpleasant having both pprModGuts and pprModDetails here
1276 pprTcGblEnv :: TcGblEnv -> SDoc
1277 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1278 tcg_insts = dfun_ids,
1280 tcg_imports = imports })
1281 = vcat [ ppr_types dfun_ids type_env
1282 , ppr_insts dfun_ids
1283 , vcat (map ppr rules)
1284 , ppr_gen_tycons (typeEnvTyCons type_env)
1285 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1286 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1288 pprModGuts :: ModGuts -> SDoc
1289 pprModGuts (ModGuts { mg_types = type_env,
1291 = vcat [ ppr_types [] type_env,
1295 ppr_types :: [Instance] -> TypeEnv -> SDoc
1296 ppr_types ispecs type_env
1297 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1299 dfun_ids = map instanceDFunId ispecs
1300 ids = [id | id <- typeEnvIds type_env, want_sig id]
1301 want_sig id | opt_PprStyle_Debug = True
1302 | otherwise = isLocalId id &&
1303 isExternalName (idName id) &&
1304 not (id `elem` dfun_ids)
1305 -- isLocalId ignores data constructors, records selectors etc.
1306 -- The isExternalName ignores local dictionary and method bindings
1307 -- that the type checker has invented. Top-level user-defined things
1308 -- have External names.
1310 ppr_insts :: [Instance] -> SDoc
1311 ppr_insts [] = empty
1312 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1314 ppr_sigs :: [Var] -> SDoc
1316 -- Print type signatures; sort by OccName
1317 = vcat (map ppr_sig (sortLe le_sig ids))
1319 le_sig id1 id2 = getOccName id1 <= getOccName id2
1320 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1322 ppr_rules :: [CoreRule] -> SDoc
1323 ppr_rules [] = empty
1324 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1325 nest 4 (pprRules rs),
1328 ppr_gen_tycons [] = empty
1329 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1330 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]