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 HsSyn ( HsModule(..), HsExtCore(..), HsGroup(..), LHsDecl,
30 SpliceDecl(..), HsBind(..), LHsBinds,
31 emptyRdrGroup, emptyRnGroup, appendGroups, plusHsValBinds,
32 nlHsApp, nlHsVar, pprLHsBinds )
33 import RdrHsSyn ( findSplice )
35 import PrelNames ( runMainIOName, rootMainKey, rOOT_MAIN, mAIN,
37 import RdrName ( RdrName, mkRdrUnqual, emptyGlobalRdrEnv )
38 import TcHsSyn ( zonkTopDecls )
39 import TcExpr ( tcInferRho )
41 import TcType ( tidyTopType, tcEqType )
42 import Inst ( showLIE )
43 import InstEnv ( extendInstEnvList, Instance, pprInstances, instanceDFunId )
44 import TcBinds ( tcTopBinds, tcHsBootSigs )
45 import TcDefaults ( tcDefaults )
46 import TcEnv ( tcExtendGlobalValEnv, iDFunId )
47 import TcRules ( tcRules )
48 import TcForeign ( tcForeignImports, tcForeignExports )
49 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
50 import TcIface ( tcExtCoreBindings, tcHiBootIface )
51 import IfaceSyn ( checkBootDecl, tyThingToIfaceDecl, IfaceExtName(..) )
52 import TcSimplify ( tcSimplifyTop )
53 import TcTyClsDecls ( tcTyAndClassDecls )
54 import LoadIface ( loadOrphanModules )
55 import RnNames ( importsFromLocalDecls, rnImports, rnExports,
56 mkRdrEnvAndImports, mkExportNameSet,
57 reportUnusedNames, reportDeprecations )
58 import RnEnv ( lookupSrcOcc_maybe )
59 import RnSource ( rnSrcDecls, rnTyClDecls, checkModDeprec )
60 import PprCore ( pprRules, pprCoreBindings )
61 import CoreSyn ( CoreRule, bindersOfBinds )
62 import ErrUtils ( Messages, mkDumpDoc, showPass )
63 import Id ( Id, mkExportedLocalId, isLocalId, idName, idType )
66 import UniqFM ( elemUFM, eltsUFM )
67 import OccName ( mkVarOccFS, plusOccEnv )
68 import Name ( Name, NamedThing(..), isExternalName, getSrcLoc, isWiredInName,
69 nameModule, nameOccName, isImplicitName, mkExternalName )
71 import TyCon ( tyConHasGenerics )
72 import SrcLoc ( srcLocSpan, Located(..), noLoc )
73 import DriverPhases ( HscSource(..), isHsBoot )
74 import HscTypes ( ModGuts(..), ModDetails(..), emptyModDetails,
75 HscEnv(..), ExternalPackageState(..),
76 IsBootInterface, noDependencies,
77 Deprecs( NoDeprecs ), plusDeprecs,
78 ForeignStubs(NoStubs),
79 TypeEnv, lookupTypeEnv, hptInstances,
80 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons, typeEnvElts,
86 import HsSyn ( HsStmtContext(..), Stmt(..), HsExpr(..),
87 HsLocalBinds(..), HsValBinds(..),
88 LStmt, LHsExpr, LHsType, mkMatch, emptyLocalBinds,
89 collectLStmtsBinders, collectLStmtBinders, nlVarPat,
90 mkFunBind, placeHolderType, noSyntaxExpr )
91 import RdrName ( GlobalRdrElt(..), globalRdrEnvElts,
92 unQualOK, lookupLocalRdrEnv, extendLocalRdrEnv )
93 import RnSource ( addTcgDUs )
94 import TcHsSyn ( mkHsDictLet, zonkTopLExpr, zonkTopBndrs )
95 import TcHsType ( kcHsType )
96 import TcMType ( zonkTcType, zonkQuantifiedTyVar )
97 import TcMatches ( tcStmts, tcDoStmt )
98 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
99 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType, isTauTy,
100 isUnLiftedType, tyClsNamesOfDFunHead, tyClsNamesOfType, isUnitTy )
101 import TcEnv ( tcLookupTyCon, tcLookupId, tcLookupGlobal )
102 import TypeRep ( TyThing(..) )
103 import RnTypes ( rnLHsType )
104 import Inst ( tcGetInstEnvs )
105 import InstEnv ( classInstances, instEnvElts )
106 import RnExpr ( rnStmts, rnLExpr )
107 import LoadIface ( loadSysInterface )
108 import IfaceEnv ( ifaceExportNames )
109 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
110 import Id ( setIdType )
111 import MkId ( unsafeCoerceId )
112 import TyCon ( tyConName )
113 import TysWiredIn ( mkListTy, unitTy )
114 import IdInfo ( GlobalIdDetails(..) )
116 import Var ( globaliseId )
117 import Name ( isBuiltInSyntax, isInternalName )
118 import OccName ( isTcOcc )
119 import NameEnv ( delListFromNameEnv )
120 import PrelNames ( iNTERACTIVE, ioTyConName, printName, itName,
121 bindIOName, thenIOName, returnIOName )
122 import HscTypes ( InteractiveContext(..),
123 ModIface(..), icPrintUnqual,
125 import BasicTypes ( Fixity, RecFlag(..) )
126 import SrcLoc ( unLoc )
127 import Data.Maybe ( isNothing )
130 import FastString ( mkFastString )
131 import Util ( sortLe )
132 import Bag ( unionBags, snocBag, emptyBag, unitBag, unionManyBags )
134 import Data.Maybe ( isJust )
139 %************************************************************************
141 Typecheck and rename a module
143 %************************************************************************
149 -> Bool -- True <=> save renamed syntax
150 -> Located (HsModule RdrName)
151 -> IO (Messages, Maybe TcGblEnv)
153 tcRnModule hsc_env hsc_src save_rn_syntax
154 (L loc (HsModule maybe_mod export_ies
155 import_decls local_decls mod_deprec))
156 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
158 let { this_pkg = thisPackage (hsc_dflags hsc_env) ;
159 this_mod = case maybe_mod of
160 Nothing -> mAIN -- 'module M where' is omitted
161 Just (L _ mod) -> mkModule this_pkg mod } ;
164 initTc hsc_env hsc_src this_mod $
167 -- Deal with imports;
168 rn_imports <- rnImports import_decls ;
169 (rdr_env, imports) <- mkRdrEnvAndImports rn_imports ;
171 let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)
172 ; dep_mods = imp_dep_mods imports
174 -- We want instance declarations from all home-package
175 -- modules below this one, including boot modules, except
176 -- ourselves. The 'except ourselves' is so that we don't
177 -- get the instances from this module's hs-boot file
178 ; want_instances :: ModuleName -> Bool
179 ; want_instances mod = mod `elemUFM` dep_mods
180 && mod /= moduleName this_mod
181 ; home_insts = hptInstances hsc_env want_instances
184 -- Record boot-file info in the EPS, so that it's
185 -- visible to loadHiBootInterface in tcRnSrcDecls,
186 -- and any other incrementally-performed imports
187 updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
189 -- Update the gbl env
191 gbl { tcg_rdr_env = plusOccEnv (tcg_rdr_env gbl) rdr_env,
192 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts,
193 tcg_imports = tcg_imports gbl `plusImportAvails` imports,
194 tcg_rn_imports = if save_rn_syntax then
198 tcg_rn_decls = if save_rn_syntax then
204 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
205 -- Fail if there are any errors so far
206 -- The error printing (if needed) takes advantage
207 -- of the tcg_env we have now set
210 -- Load any orphan-module interfaces, so that
211 -- their rules and instance decls will be found
212 loadOrphanModules (imp_orphs imports) ;
214 traceRn (text "rn1a") ;
215 -- Rename and type check the declarations
216 tcg_env <- if isHsBoot hsc_src then
217 tcRnHsBootDecls local_decls
219 tcRnSrcDecls local_decls ;
220 setGblEnv tcg_env $ do {
222 traceRn (text "rn3") ;
224 -- Report the use of any deprecated things
225 -- We do this before processsing the export list so
226 -- that we don't bleat about re-exporting a deprecated
227 -- thing (especially via 'module Foo' export item)
228 -- Only uses in the body of the module are complained about
229 reportDeprecations (hsc_dflags hsc_env) tcg_env ;
231 -- Process the export list
232 rn_exports <- rnExports export_ies ;
233 let { liftM2' fn a b = do a' <- a; b' <- b; return (fn a' b') } ;
234 exports <- mkExportNameSet (isJust maybe_mod) (liftM2' (,) rn_exports export_ies) ;
236 -- Check whether the entire module is deprecated
237 -- This happens only once per module
238 let { mod_deprecs = checkModDeprec mod_deprec } ;
240 -- Add exports and deprecations to envt
241 let { final_env = tcg_env { tcg_exports = exports,
242 tcg_rn_exports = if save_rn_syntax then
245 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
246 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
248 -- A module deprecation over-rides the earlier ones
251 -- Report unused names
252 reportUnusedNames export_ies final_env ;
254 -- Dump output and return
261 %************************************************************************
263 Type-checking external-core modules
265 %************************************************************************
268 tcRnExtCore :: HscEnv
270 -> IO (Messages, Maybe ModGuts)
271 -- Nothing => some error occurred
273 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
274 -- The decls are IfaceDecls; all names are original names
275 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
277 initTc hsc_env ExtCoreFile this_mod $ do {
279 let { ldecls = map noLoc decls } ;
281 -- Deal with the type declarations; first bring their stuff
282 -- into scope, then rname them, then type check them
283 tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ;
285 setGblEnv tcg_env $ do {
287 rn_decls <- rnTyClDecls ldecls ;
290 -- Dump trace of renaming part
291 rnDump (ppr rn_decls) ;
293 -- Typecheck them all together so that
294 -- any mutually recursive types are done right
295 tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ;
296 -- Make the new type env available to stuff slurped from interface files
298 setGblEnv tcg_env $ do {
300 -- Now the core bindings
301 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
305 bndrs = bindersOfBinds core_binds ;
306 my_exports = mkNameSet (map idName bndrs) ;
307 -- ToDo: export the data types also?
309 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
311 mod_guts = ModGuts { mg_module = this_mod,
313 mg_usages = [], -- ToDo: compute usage
314 mg_dir_imps = [], -- ??
315 mg_deps = noDependencies, -- ??
316 mg_exports = my_exports,
317 mg_types = final_type_env,
318 mg_insts = tcg_insts tcg_env,
320 mg_binds = core_binds,
323 mg_rdr_env = emptyGlobalRdrEnv,
324 mg_fix_env = emptyFixityEnv,
325 mg_deprecs = NoDeprecs,
329 tcCoreDump mod_guts ;
334 mkFakeGroup decls -- Rather clumsy; lots of unused fields
335 = emptyRdrGroup { hs_tyclds = decls }
339 %************************************************************************
341 Type-checking the top level of a module
343 %************************************************************************
346 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
347 -- Returns the variables free in the decls
348 -- Reason: solely to report unused imports and bindings
350 = do { -- Load the hi-boot interface for this module, if any
351 -- We do this now so that the boot_names can be passed
352 -- to tcTyAndClassDecls, because the boot_names are
353 -- automatically considered to be loop breakers
355 boot_iface <- tcHiBootIface mod ;
357 -- Do all the declarations
358 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_iface decls) ;
360 -- tcSimplifyTop deals with constant or ambiguous InstIds.
361 -- How could there be ambiguous ones? They can only arise if a
362 -- top-level decl falls under the monomorphism
363 -- restriction, and no subsequent decl instantiates its
364 -- type. (Usually, ambiguous type variables are resolved
365 -- during the generalisation step.)
366 traceTc (text "Tc8") ;
367 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
368 -- Setting the global env exposes the instances to tcSimplifyTop
369 -- Setting the local env exposes the local Ids to tcSimplifyTop,
370 -- so that we get better error messages (monomorphism restriction)
372 -- Backsubstitution. This must be done last.
373 -- Even tcSimplifyTop may do some unification.
374 traceTc (text "Tc9") ;
375 let { (tcg_env, _) = tc_envs ;
376 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
377 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
380 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
383 let { final_type_env = extendTypeEnvWithIds type_env bind_ids
384 ; tcg_env' = tcg_env { tcg_type_env = final_type_env,
387 tcg_fords = fords' } } ;
389 -- Make the new type env available to stuff slurped from interface files
390 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
392 -- Compare the hi-boot iface (if any) with the real thing
393 dfun_binds <- checkHiBootIface tcg_env' boot_iface ;
395 return (tcg_env' { tcg_binds = tcg_binds tcg_env' `unionBags` dfun_binds })
398 tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
399 -- Loops around dealing with each top level inter-splice group
400 -- in turn, until it's dealt with the entire module
401 tc_rn_src_decls boot_details ds
402 = do { let { (first_group, group_tail) = findSplice ds } ;
403 -- If ds is [] we get ([], Nothing)
405 -- Type check the decls up to, but not including, the first splice
406 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_details first_group ;
408 -- Bale out if errors; for example, error recovery when checking
409 -- the RHS of 'main' can mean that 'main' is not in the envt for
410 -- the subsequent checkMain test
415 -- If there is no splice, we're nearly done
417 Nothing -> do { -- Last thing: check for `main'
418 tcg_env <- checkMain ;
419 return (tcg_env, tcl_env)
422 -- If there's a splice, we must carry on
423 Just (SpliceDecl splice_expr, rest_ds) -> do {
425 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
428 -- Rename the splice expression, and get its supporting decls
429 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
430 failIfErrsM ; -- Don't typecheck if renaming failed
432 -- Execute the splice
433 spliced_decls <- tcSpliceDecls rn_splice_expr ;
435 -- Glue them on the front of the remaining decls and loop
436 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
437 tc_rn_src_decls boot_details (spliced_decls ++ rest_ds)
442 %************************************************************************
444 Compiling hs-boot source files, and
445 comparing the hi-boot interface with the real thing
447 %************************************************************************
450 tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
451 tcRnHsBootDecls decls
452 = do { let { (first_group, group_tail) = findSplice decls }
455 Just stuff -> spliceInHsBootErr stuff
458 -- Rename the declarations
459 ; (tcg_env, rn_group) <- rnTopSrcDecls first_group
460 ; setGblEnv tcg_env $ do {
462 -- Todo: check no foreign decls, no rules, no default decls
464 -- Typecheck type/class decls
465 ; traceTc (text "Tc2")
466 ; let tycl_decls = hs_tyclds rn_group
467 ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls)
468 ; setGblEnv tcg_env $ do {
470 -- Typecheck instance decls
471 ; traceTc (text "Tc3")
472 ; (tcg_env, inst_infos, _binds) <- tcInstDecls1 tycl_decls (hs_instds rn_group)
473 ; setGblEnv tcg_env $ do {
475 -- Typecheck value declarations
476 ; traceTc (text "Tc5")
477 ; val_ids <- tcHsBootSigs (hs_valds rn_group)
480 -- No simplification or zonking to do
481 ; traceTc (text "Tc7a")
482 ; gbl_env <- getGblEnv
484 -- Make the final type-env
485 -- Include the dfun_ids so that their type sigs get
486 -- are written into the interface file
487 ; let { type_env0 = tcg_type_env gbl_env
488 ; type_env1 = extendTypeEnvWithIds type_env0 val_ids
489 ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids
490 ; dfun_ids = map iDFunId inst_infos }
491 ; return (gbl_env { tcg_type_env = type_env2 })
494 spliceInHsBootErr (SpliceDecl (L loc _), _)
495 = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files"))
498 Once we've typechecked the body of the module, we want to compare what
499 we've found (gathered in a TypeEnv) with the hi-boot details (if any).
502 checkHiBootIface :: TcGblEnv -> ModDetails -> TcM (LHsBinds Id)
503 -- Compare the hi-boot file for this module (if there is one)
504 -- with the type environment we've just come up with
505 -- In the common case where there is no hi-boot file, the list
506 -- of boot_names is empty.
508 -- The bindings we return give bindings for the dfuns defined in the
509 -- hs-boot file, such as $fbEqT = $fEqT
512 (TcGblEnv { tcg_insts = local_insts, tcg_type_env = local_type_env })
513 (ModDetails { md_insts = boot_insts, md_types = boot_type_env })
514 = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts)) ;
515 ; mapM_ check_one (typeEnvElts boot_type_env)
516 ; dfun_binds <- mapM check_inst boot_insts
517 ; return (unionManyBags dfun_binds) }
522 | Just real_thing <- lookupTypeEnv local_type_env name
523 = do { let boot_decl = tyThingToIfaceDecl ext_nm boot_thing
524 real_decl = tyThingToIfaceDecl ext_nm real_thing
525 ; checkTc (checkBootDecl boot_decl real_decl)
526 (bootMisMatch boot_thing boot_decl real_decl) }
527 -- The easiest way to check compatibility is to convert to
528 -- iface syntax, where we already have good comparison functions
530 = addErrTc (missingBootThing boot_thing)
532 name = getName boot_thing
534 ext_nm name = ExtPkg (nameModule name) (nameOccName name)
535 -- Just enough to compare; no versions etc needed
537 no_check name = isWiredInName name -- No checking for wired-in names. In particular,
538 -- 'error' is handled by a rather gross hack
539 -- (see comments in GHC.Err.hs-boot)
540 || name `elem` dfun_names
541 || isImplicitName name -- Has a parent, which we'll check
543 dfun_names = map getName boot_insts
546 = case [dfun | inst <- local_insts,
547 let dfun = instanceDFunId inst,
548 idType dfun `tcEqType` boot_inst_ty ] of
549 [] -> do { addErrTc (instMisMatch boot_inst); return emptyBag }
550 (dfun:_) -> return (unitBag $ noLoc $ VarBind local_boot_dfun (nlHsVar dfun))
552 boot_dfun = instanceDFunId boot_inst
553 boot_inst_ty = idType boot_dfun
554 local_boot_dfun = mkExportedLocalId (idName boot_dfun) boot_inst_ty
557 missingBootThing thing
558 = ppr thing <+> ptext SLIT("is defined in the hs-boot file, but not in the module")
559 bootMisMatch thing boot_decl real_decl
560 = ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file")
563 2 (ptext SLIT("is defined in the hs-boot file, but not in the module"))
567 %************************************************************************
569 Type-checking the top level of a module
571 %************************************************************************
573 tcRnGroup takes a bunch of top-level source-code declarations, and
575 * gets supporting declarations from interface files
578 * and augments the TcGblEnv with the results
580 In Template Haskell it may be called repeatedly for each group of
581 declarations. It expects there to be an incoming TcGblEnv in the
582 monad; it augments it and returns the new TcGblEnv.
585 tcRnGroup :: ModDetails -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
586 -- Returns the variables free in the decls, for unused-binding reporting
587 tcRnGroup boot_details decls
588 = do { -- Rename the declarations
589 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
590 setGblEnv tcg_env $ do {
592 -- Typecheck the declarations
593 tcTopSrcDecls boot_details rn_decls
596 ------------------------------------------------
597 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
599 = do { -- Bring top level binders into scope
600 tcg_env <- importsFromLocalDecls group ;
601 setGblEnv tcg_env $ do {
603 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
605 -- Rename the source decls
606 (tcg_env, rn_decls) <- rnSrcDecls group ;
609 -- save the renamed syntax, if we want it
611 | Just grp <- tcg_rn_decls tcg_env
612 = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) }
616 -- Dump trace of renaming part
617 rnDump (ppr rn_decls) ;
619 return (tcg_env', rn_decls)
622 ------------------------------------------------
623 tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
624 tcTopSrcDecls boot_details
625 (HsGroup { hs_tyclds = tycl_decls,
626 hs_instds = inst_decls,
627 hs_fords = foreign_decls,
628 hs_defds = default_decls,
629 hs_ruleds = rule_decls,
630 hs_valds = val_binds })
631 = do { -- Type-check the type and class decls, and all imported decls
632 -- The latter come in via tycl_decls
633 traceTc (text "Tc2") ;
635 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ;
636 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
637 -- an error we'd better stop now, to avoid a cascade
639 -- Make these type and class decls available to stuff slurped from interface files
640 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
643 setGblEnv tcg_env $ do {
644 -- Source-language instances, including derivings,
645 -- and import the supporting declarations
646 traceTc (text "Tc3") ;
647 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
648 setGblEnv tcg_env $ do {
650 -- Foreign import declarations next. No zonking necessary
651 -- here; we can tuck them straight into the global environment.
652 traceTc (text "Tc4") ;
653 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
654 tcExtendGlobalValEnv fi_ids $ do {
656 -- Default declarations
657 traceTc (text "Tc4a") ;
658 default_tys <- tcDefaults default_decls ;
659 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
661 -- Value declarations next
662 -- We also typecheck any extra binds that came out
663 -- of the "deriving" process (deriv_binds)
664 traceTc (text "Tc5") ;
665 (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ;
666 setLclTypeEnv tcl_env $ do {
668 -- Second pass over class and instance declarations,
669 traceTc (text "Tc6") ;
670 (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ;
671 showLIE (text "after instDecls2") ;
674 -- They need to be zonked, so we return them
675 traceTc (text "Tc7") ;
676 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
679 rules <- tcRules rule_decls ;
682 traceTc (text "Tc7a") ;
683 tcg_env <- getGblEnv ;
684 let { all_binds = tc_val_binds `unionBags`
685 inst_binds `unionBags`
688 -- Extend the GblEnv with the (as yet un-zonked)
689 -- bindings, rules, foreign decls
690 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
691 tcg_rules = tcg_rules tcg_env ++ rules,
692 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
693 return (tcg_env', tcl_env)
698 %************************************************************************
702 %************************************************************************
705 checkMain :: TcM TcGblEnv
706 -- If we are in module Main, check that 'main' is defined.
708 = do { ghc_mode <- getGhcMode ;
709 tcg_env <- getGblEnv ;
711 let { main_mod = mainModIs dflags ;
712 main_fn = case mainFunIs dflags of {
713 Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ;
714 Nothing -> main_RDR_Unqual } } ;
716 check_main ghc_mode tcg_env main_mod main_fn
720 check_main ghc_mode tcg_env main_mod main_fn
722 = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >>
726 = addErrCtxt mainCtxt $
727 do { mb_main <- lookupSrcOcc_maybe main_fn
728 -- Check that 'main' is in scope
729 -- It might be imported from another module!
731 Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn)
735 { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn)
736 ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) }
737 -- :Main.main :: IO () = runMainIO main
739 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
742 -- The function that the RTS invokes is always :Main.main,
743 -- which we call root_main_id.
744 -- (Because GHC allows the user to have a module not called
745 -- Main as the main module, we can't rely on the main function
746 -- being called "Main.main". That's why root_main_id has a fixed
748 -- We also make root_main_id an implicit Id, by making main_name
749 -- its parent (hence (Just main_name)). That has the effect
750 -- of preventing its type and unfolding from getting out into
751 -- the interface file. Otherwise we can end up with two defns
752 -- for 'main' in the interface file!
754 ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN
755 (mkVarOccFS FSLIT("main"))
756 (Just main_name) (getSrcLoc main_name)
757 ; root_main_id = mkExportedLocalId root_main_name ty
758 ; main_bind = noLoc (VarBind root_main_id main_expr) }
760 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
762 tcg_dus = tcg_dus tcg_env
763 `plusDU` usesOnly (unitFV main_name)
764 -- Record the use of 'main', so that we don't
765 -- complain about it being defined but not used
769 mod = tcg_mod tcg_env
771 complain_no_main | ghc_mode == Interactive = return ()
772 | otherwise = failWithTc noMainMsg
773 -- In interactive mode, don't worry about the absence of 'main'
774 -- In other modes, fail altogether, so that we don't go on
775 -- and complain a second time when processing the export list.
777 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
778 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
779 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
782 %*********************************************************
786 %*********************************************************
790 setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a
791 setInteractiveContext hsc_env icxt thing_inside
793 -- Initialise the tcg_inst_env with instances
794 -- from all home modules. This mimics the more selective
795 -- call to hptInstances in tcRnModule
796 dfuns = hptInstances hsc_env (\mod -> True)
798 updGblEnv (\env -> env {
799 tcg_rdr_env = ic_rn_gbl_env icxt,
800 tcg_type_env = ic_type_env icxt,
801 tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $
803 updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $
805 do { traceTc (text "setIC" <+> ppr (ic_type_env icxt))
812 -> InteractiveContext
814 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
815 -- The returned [Name] is the same as the input except for
816 -- ExprStmt, in which case the returned [Name] is [itName]
818 -- The returned TypecheckedHsExpr is of type IO [ () ],
819 -- a list of the bound values, coerced to ().
821 tcRnStmt hsc_env ictxt rdr_stmt
822 = initTcPrintErrors hsc_env iNTERACTIVE $
823 setInteractiveContext hsc_env ictxt $ do {
825 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
826 (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ;
827 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
830 -- The real work is done here
831 (bound_ids, tc_expr) <- mkPlan rn_stmt ;
832 zonked_expr <- zonkTopLExpr tc_expr ;
833 zonked_ids <- zonkTopBndrs bound_ids ;
835 -- None of the Ids should be of unboxed type, because we
836 -- cast them all to HValues in the end!
837 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
839 traceTc (text "tcs 1") ;
840 let { -- (a) Make all the bound ids "global" ids, now that
841 -- they're notionally top-level bindings. This is
842 -- important: otherwise when we come to compile an expression
843 -- using these ids later, the byte code generator will consider
844 -- the occurrences to be free rather than global.
846 -- (b) Tidy their types; this is important, because :info may
847 -- ask to look at them, and :info expects the things it looks
848 -- up to have tidy types
849 global_ids = map globaliseAndTidy zonked_ids ;
851 -- Update the interactive context
852 rn_env = ic_rn_local_env ictxt ;
853 type_env = ic_type_env ictxt ;
855 bound_names = map idName global_ids ;
856 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
858 -- Remove any shadowed bindings from the type_env;
859 -- they are inaccessible but might, I suppose, cause
860 -- a space leak if we leave them there
861 shadowed = [ n | name <- bound_names,
862 let rdr_name = mkRdrUnqual (nameOccName name),
863 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
865 filtered_type_env = delListFromNameEnv type_env shadowed ;
866 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
868 new_ic = ictxt { ic_rn_local_env = new_rn_env,
869 ic_type_env = new_type_env }
872 dumpOptTcRn Opt_D_dump_tc
873 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
874 text "Typechecked expr" <+> ppr zonked_expr]) ;
876 returnM (new_ic, bound_names, zonked_expr)
879 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
880 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
882 globaliseAndTidy :: Id -> Id
884 -- Give the Id a Global Name, and tidy its type
885 = setIdType (globaliseId VanillaGlobal id) tidy_type
887 tidy_type = tidyTopType (idType id)
890 Here is the grand plan, implemented in tcUserStmt
892 What you type The IO [HValue] that hscStmt returns
893 ------------- ------------------------------------
894 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
897 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
900 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
901 [NB: result not printed] bindings: [it]
903 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
904 result showable) bindings: [it]
906 expr (of non-IO type,
907 result not showable) ==> error
911 ---------------------------
912 type PlanResult = ([Id], LHsExpr Id)
913 type Plan = TcM PlanResult
915 runPlans :: [Plan] -> TcM PlanResult
916 -- Try the plans in order. If one fails (by raising an exn), try the next.
917 -- If one succeeds, take it.
918 runPlans [] = panic "runPlans"
920 runPlans (p:ps) = tryTcLIE_ (runPlans ps) p
923 mkPlan :: LStmt Name -> TcM PlanResult
924 mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt
925 = do { uniq <- newUnique -- is treated very specially
926 ; let fresh_it = itName uniq
927 the_bind = L loc $ mkFunBind (L loc fresh_it) matches
928 matches = [mkMatch [] expr emptyLocalBinds]
929 let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] []))
930 bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr
931 (HsVar bindIOName) noSyntaxExpr
932 print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it))
933 (HsVar thenIOName) placeHolderType
936 -- [it <- e; print it] but not if it::()
938 -- [let it = e; print it]
939 ; runPlans [ -- Plan A
940 do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it]
941 ; it_ty <- zonkTcType (idType it_id)
942 ; ifM (isUnitTy it_ty) failM
945 -- Plan B; a naked bind statment
946 tcGhciStmts [bind_stmt],
948 -- Plan C; check that the let-binding is typeable all by itself.
949 -- If not, fail; if so, try to print it.
950 -- The two-step process avoids getting two errors: one from
951 -- the expression itself, and one from the 'print it' part
952 -- This two-step story is very clunky, alas
953 do { checkNoErrs (tcGhciStmts [let_stmt])
954 --- checkNoErrs defeats the error recovery of let-bindings
955 ; tcGhciStmts [let_stmt, print_it] }
958 mkPlan stmt@(L loc (BindStmt {}))
959 | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt
960 = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v))
961 (HsVar thenIOName) placeHolderType
963 -- [stmt; print v] but not if v::()
965 ; runPlans [do { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v]
966 ; v_ty <- zonkTcType (idType v_id)
967 ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM
975 ---------------------------
976 tcGhciStmts :: [LStmt Name] -> TcM PlanResult
978 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
979 ret_id <- tcLookupId returnIOName ; -- return @ IO
981 io_ty = mkTyConApp ioTyCon [] ;
982 ret_ty = mkListTy unitTy ;
983 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
985 names = map unLoc (collectLStmtsBinders stmts) ;
987 -- mk_return builds the expression
988 -- returnIO @ [()] [coerce () x, .., coerce () z]
990 -- Despite the inconvenience of building the type applications etc,
991 -- this *has* to be done in type-annotated post-typecheck form
992 -- because we are going to return a list of *polymorphic* values
993 -- coerced to type (). If we built a *source* stmt
994 -- return [coerce x, ..., coerce z]
995 -- then the type checker would instantiate x..z, and we wouldn't
996 -- get their *polymorphic* values. (And we'd get ambiguity errs
997 -- if they were overloaded, since they aren't applied to anything.)
998 mk_return ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
999 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
1000 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
1004 -- OK, we're ready to typecheck the stmts
1005 traceTc (text "tcs 2") ;
1006 ((tc_stmts, ids), lie) <- getLIE $
1007 tcStmts DoExpr (tcDoStmt io_ty) stmts io_ret_ty $ \ _ ->
1008 mappM tcLookupId names ;
1009 -- Look up the names right in the middle,
1010 -- where they will all be in scope
1012 -- Simplify the context
1013 const_binds <- checkNoErrs (tcSimplifyInteractive lie) ;
1014 -- checkNoErrs ensures that the plan fails if context redn fails
1016 return (ids, mkHsDictLet const_binds $
1017 noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty))
1022 tcRnExpr just finds the type of an expression
1026 -> InteractiveContext
1029 tcRnExpr hsc_env ictxt rdr_expr
1030 = initTcPrintErrors hsc_env iNTERACTIVE $
1031 setInteractiveContext hsc_env ictxt $ do {
1033 (rn_expr, fvs) <- rnLExpr rdr_expr ;
1036 -- Now typecheck the expression;
1037 -- it might have a rank-2 type (e.g. :t runST)
1038 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
1039 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
1040 tcSimplifyInteractive lie_top ;
1041 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
1043 let { all_expr_ty = mkForAllTys qtvs' $
1044 mkFunTys (map idType dict_ids) $
1046 zonkTcType all_expr_ty
1049 smpl_doc = ptext SLIT("main expression")
1052 tcRnType just finds the kind of a type
1056 -> InteractiveContext
1059 tcRnType hsc_env ictxt rdr_type
1060 = initTcPrintErrors hsc_env iNTERACTIVE $
1061 setInteractiveContext hsc_env ictxt $ do {
1063 rn_type <- rnLHsType doc rdr_type ;
1066 -- Now kind-check the type
1067 (ty', kind) <- kcHsType rn_type ;
1071 doc = ptext SLIT("In GHCi input")
1077 %************************************************************************
1079 More GHCi stuff, to do with browsing and getting info
1081 %************************************************************************
1085 -- ASSUMES that the module is either in the HomePackageTable or is
1086 -- a package module with an interface on disk. If neither of these is
1087 -- true, then the result will be an error indicating the interface
1088 -- could not be found.
1089 getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe NameSet)
1090 getModuleExports hsc_env mod
1091 = initTc hsc_env HsSrcFile iNTERACTIVE (tcGetModuleExports mod)
1093 tcGetModuleExports :: Module -> TcM NameSet
1094 tcGetModuleExports mod = do
1095 let doc = ptext SLIT("context for compiling statements")
1096 iface <- initIfaceTcRn $ loadSysInterface doc mod
1097 loadOrphanModules (dep_orphs (mi_deps iface))
1098 -- Load any orphan-module interfaces,
1099 -- so their instances are visible
1100 ifaceExportNames (mi_exports iface)
1102 tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name])
1103 tcRnLookupRdrName hsc_env rdr_name
1104 = initTcPrintErrors hsc_env iNTERACTIVE $
1105 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1106 lookup_rdr_name rdr_name
1108 lookup_rdr_name rdr_name = do {
1109 -- If the identifier is a constructor (begins with an
1110 -- upper-case letter), then we need to consider both
1111 -- constructor and type class identifiers.
1112 let { rdr_names = dataTcOccs rdr_name } ;
1114 -- results :: [Either Messages Name]
1115 results <- mapM (tryTcErrs . lookupOccRn) rdr_names ;
1117 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1118 -- The successful lookups will be (Just name)
1119 let { (warns_s, good_names) = unzip [ (msgs, name)
1120 | (msgs, Just name) <- results] ;
1121 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1123 -- Fail if nothing good happened, else add warnings
1124 if null good_names then
1125 -- No lookup succeeded, so
1126 -- pick the first error message and report it
1127 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1128 -- while the other is "X is not in scope",
1129 -- we definitely want the former; but we might pick the latter
1130 do { addMessages (head errs_s) ; failM }
1131 else -- Add deprecation warnings
1132 mapM_ addMessages warns_s ;
1138 tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing)
1139 tcRnLookupName hsc_env name
1140 = initTcPrintErrors hsc_env iNTERACTIVE $
1141 setInteractiveContext hsc_env (hsc_IC hsc_env) $
1145 tcRnGetInfo :: HscEnv
1147 -> IO (Maybe (TyThing, Fixity, [Instance]))
1149 -- Used to implemnent :info in GHCi
1151 -- Look up a RdrName and return all the TyThings it might be
1152 -- A capitalised RdrName is given to us in the DataName namespace,
1153 -- but we want to treat it as *both* a data constructor
1154 -- *and* as a type or class constructor;
1155 -- hence the call to dataTcOccs, and we return up to two results
1156 tcRnGetInfo hsc_env name
1157 = initTcPrintErrors hsc_env iNTERACTIVE $
1158 let ictxt = hsc_IC hsc_env in
1159 setInteractiveContext hsc_env ictxt $ do
1161 -- Load the interface for all unqualified types and classes
1162 -- That way we will find all the instance declarations
1163 -- (Packages have not orphan modules, and we assume that
1164 -- in the home package all relevant modules are loaded.)
1165 loadUnqualIfaces ictxt
1167 thing <- tcLookupGlobal name
1168 fixity <- lookupFixityRn name
1169 ispecs <- lookupInsts (icPrintUnqual ictxt) thing
1170 return (thing, fixity, ispecs)
1173 lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance]
1174 -- Filter the instances by the ones whose tycons (or clases resp)
1175 -- are in scope unqualified. Otherwise we list a whole lot too many!
1176 lookupInsts print_unqual (AClass cls)
1177 = do { inst_envs <- tcGetInstEnvs
1179 | ispec <- classInstances inst_envs cls
1180 , plausibleDFun print_unqual (instanceDFunId ispec) ] }
1182 lookupInsts print_unqual (ATyCon tc)
1183 = do { eps <- getEps -- Load all instances for all classes that are
1184 -- in the type environment (which are all the ones
1185 -- we've seen in any interface file so far)
1186 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1188 | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie
1189 , let dfun = instanceDFunId ispec
1191 , plausibleDFun print_unqual dfun ] }
1193 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1194 tc_name = tyConName tc
1196 lookupInsts print_unqual other = return []
1198 plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified
1199 = all ok (nameSetToList (tyClsNamesOfType (idType dfun)))
1201 ok name | isBuiltInSyntax name = True
1202 | isExternalName name =
1203 isNothing $ fst print_unqual (nameModule name)
1207 loadUnqualIfaces :: InteractiveContext -> TcM ()
1208 -- Load the home module for everything that is in scope unqualified
1209 -- This is so that we can accurately report the instances for
1211 loadUnqualIfaces ictxt
1213 mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods))
1215 unqual_mods = [ nameModule name
1216 | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt),
1217 let name = gre_name gre,
1218 not (isInternalName name),
1219 isTcOcc (nameOccName name), -- Types and classes only
1220 unQualOK gre ] -- In scope unqualified
1221 doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified")
1225 %************************************************************************
1229 %************************************************************************
1232 rnDump :: SDoc -> TcRn ()
1233 -- Dump, with a banner, if -ddump-rn
1234 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1236 tcDump :: TcGblEnv -> TcRn ()
1238 = do { dflags <- getDOpts ;
1240 -- Dump short output if -ddump-types or -ddump-tc
1241 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1242 (dumpTcRn short_dump) ;
1244 -- Dump bindings if -ddump-tc
1245 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1248 short_dump = pprTcGblEnv env
1249 full_dump = pprLHsBinds (tcg_binds env)
1250 -- NB: foreign x-d's have undefined's in their types;
1251 -- hence can't show the tc_fords
1254 = do { dflags <- getDOpts ;
1255 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1256 (dumpTcRn (pprModGuts mod_guts)) ;
1258 -- Dump bindings if -ddump-tc
1259 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1261 full_dump = pprCoreBindings (mg_binds mod_guts)
1263 -- It's unpleasant having both pprModGuts and pprModDetails here
1264 pprTcGblEnv :: TcGblEnv -> SDoc
1265 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1266 tcg_insts = dfun_ids,
1268 tcg_imports = imports })
1269 = vcat [ ppr_types dfun_ids type_env
1270 , ppr_insts dfun_ids
1271 , vcat (map ppr rules)
1272 , ppr_gen_tycons (typeEnvTyCons type_env)
1273 , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports))
1274 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1276 pprModGuts :: ModGuts -> SDoc
1277 pprModGuts (ModGuts { mg_types = type_env,
1279 = vcat [ ppr_types [] type_env,
1283 ppr_types :: [Instance] -> TypeEnv -> SDoc
1284 ppr_types ispecs type_env
1285 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1287 dfun_ids = map instanceDFunId ispecs
1288 ids = [id | id <- typeEnvIds type_env, want_sig id]
1289 want_sig id | opt_PprStyle_Debug = True
1290 | otherwise = isLocalId id &&
1291 isExternalName (idName id) &&
1292 not (id `elem` dfun_ids)
1293 -- isLocalId ignores data constructors, records selectors etc.
1294 -- The isExternalName ignores local dictionary and method bindings
1295 -- that the type checker has invented. Top-level user-defined things
1296 -- have External names.
1298 ppr_insts :: [Instance] -> SDoc
1299 ppr_insts [] = empty
1300 ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs)
1302 ppr_sigs :: [Var] -> SDoc
1304 -- Print type signatures; sort by OccName
1305 = vcat (map ppr_sig (sortLe le_sig ids))
1307 le_sig id1 id2 = getOccName id1 <= getOccName id2
1308 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1310 ppr_rules :: [CoreRule] -> SDoc
1311 ppr_rules [] = empty
1312 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1313 nest 4 (pprRules rs),
1316 ppr_gen_tycons [] = empty
1317 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1318 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]