2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
9 mkExportEnv, getModuleContents, tcRnStmt,
10 tcRnGetInfo, tcRnExpr, tcRnType,
17 #include "HsVersions.h"
20 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
23 import CmdLineOpts ( DynFlag(..), opt_PprStyle_Debug, dopt )
24 import DriverState ( v_MainModIs, v_MainFunIs )
25 import HsSyn ( HsModule(..), HsExtCore(..), HsGroup(..), LHsDecl, SpliceDecl(..), HsBind(..),
26 nlHsApp, nlHsVar, pprLHsBinds )
27 import RdrHsSyn ( findSplice )
29 import PrelNames ( runIOName, rootMainName, mAIN_Name,
31 import RdrName ( RdrName, mkRdrUnqual, emptyGlobalRdrEnv,
33 import TcHsSyn ( zonkTopDecls )
34 import TcExpr ( tcInferRho )
36 import TcType ( tidyTopType, tcEqType, mkTyVarTys, substTyWith )
37 import Inst ( showLIE )
38 import TcBinds ( tcTopBinds )
39 import TcDefaults ( tcDefaults )
40 import TcEnv ( tcExtendGlobalValEnv )
41 import TcRules ( tcRules )
42 import TcForeign ( tcForeignImports, tcForeignExports )
43 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
44 import TcIface ( tcExtCoreBindings )
45 import TcSimplify ( tcSimplifyTop )
46 import TcTyClsDecls ( tcTyAndClassDecls )
47 import LoadIface ( loadOrphanModules, loadHiBootInterface )
48 import IfaceEnv ( lookupOrig )
49 import RnNames ( importsFromLocalDecls, rnImports, exportsFromAvail,
50 reportUnusedNames, reportDeprecations )
51 import RnEnv ( lookupSrcOcc_maybe )
52 import RnSource ( rnSrcDecls, rnTyClDecls, checkModDeprec )
53 import PprCore ( pprIdRules, pprCoreBindings )
54 import CoreSyn ( IdCoreRule, bindersOfBinds )
55 import ErrUtils ( Messages, mkDumpDoc, showPass )
56 import Id ( mkExportedLocalId, isLocalId, idName, idType )
58 import Module ( mkHomeModule, mkModuleName, moduleName, moduleEnvElts )
59 import OccName ( mkVarOcc )
60 import Name ( Name, isExternalName, getSrcLoc, getOccName )
62 import TyCon ( tyConHasGenerics, isSynTyCon, getSynTyConDefn, tyConKind )
63 import SrcLoc ( srcLocSpan, Located(..), noLoc )
65 import HscTypes ( ModGuts(..), HscEnv(..), ExternalPackageState(..),
66 GhciMode(..), noDependencies, isOneShot,
67 Deprecs( NoDeprecs ), ModIface(..), plusDeprecs,
68 ForeignStubs(NoStubs), TyThing(..),
69 TypeEnv, lookupTypeEnv,
70 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
71 emptyFixityEnv, availName
74 import HsSyn ( HsStmtContext(..), Stmt(..), HsExpr(..), HsBindGroup(..),
75 LStmt, LHsExpr, LHsType, mkMatchGroup,
76 collectStmtsBinders, mkSimpleMatch, placeHolderType,
77 nlLetStmt, nlExprStmt, nlBindStmt, nlResultStmt, nlVarPat )
78 import RdrName ( GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
79 Provenance(..), ImportSpec(..),
80 lookupLocalRdrEnv, extendLocalRdrEnv )
81 import RnSource ( addTcgDUs )
82 import TcHsSyn ( mkHsLet, zonkTopLExpr, zonkTopBndrs )
83 import TcHsType ( kcHsType )
84 import TcExpr ( tcCheckRho )
85 import TcIface ( loadImportedInsts )
86 import TcMType ( zonkTcType )
87 import TcUnify ( unifyTyConApp )
88 import TcMatches ( tcStmtsAndThen, TcStmtCtxt(..) )
89 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
90 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType,
91 isUnLiftedType, tyClsNamesOfDFunHead )
92 import TcEnv ( tcLookupTyCon, tcLookupId, tcLookupGlobal )
93 import RnTypes ( rnLHsType )
94 import Inst ( tcStdSyntaxName, tcGetInstEnvs )
95 import InstEnv ( DFunId, classInstances, instEnvElts )
96 import RnExpr ( rnStmts, rnLExpr )
97 import RnNames ( exportsToAvails )
98 import LoadIface ( loadSrcInterface )
99 import IfaceSyn ( IfaceDecl(..), IfaceClassOp(..), IfaceConDecl(..),
100 IfaceExtName(..), IfaceConDecls(..), IfaceInst(..),
101 tyThingToIfaceDecl, dfunToIfaceInst )
102 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
103 import Id ( Id, isImplicitId, globalIdDetails )
104 import MkId ( unsafeCoerceId )
105 import DataCon ( dataConTyCon )
106 import TyCon ( tyConName )
107 import TysWiredIn ( mkListTy, unitTy )
108 import IdInfo ( GlobalIdDetails(..) )
109 import SrcLoc ( interactiveSrcLoc, unLoc )
111 import Var ( globaliseId )
112 import Name ( nameOccName, nameModuleName )
113 import NameEnv ( delListFromNameEnv )
114 import PrelNames ( iNTERACTIVE, ioTyConName, printName, monadNames, itName, returnIOName )
115 import Module ( ModuleName, lookupModuleEnvByName )
116 import HscTypes ( InteractiveContext(..), ExternalPackageState( eps_PTE ),
117 HomeModInfo(..), typeEnvElts, typeEnvClasses,
118 availNames, icPrintUnqual,
119 ModDetails(..), Dependencies(..) )
120 import BasicTypes ( RecFlag(..), Fixity )
121 import Bag ( unitBag )
122 import ListSetOps ( removeDups )
123 import Panic ( ghcError, GhcException(..) )
124 import SrcLoc ( SrcLoc )
127 import FastString ( mkFastString )
128 import Util ( sortLe )
129 import Bag ( unionBags, snocBag )
131 import Maybe ( isJust )
136 %************************************************************************
138 Typecheck and rename a module
140 %************************************************************************
145 -> Located (HsModule RdrName)
146 -> IO (Messages, Maybe TcGblEnv)
148 tcRnModule hsc_env (L loc (HsModule maybe_mod exports
149 import_decls local_decls mod_deprec))
150 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
152 let { this_mod = case maybe_mod of
153 Nothing -> mkHomeModule mAIN_Name
154 -- 'module M where' is omitted
155 Just (L _ mod) -> mod } ;
158 initTc hsc_env this_mod $
160 do { -- Deal with imports; sets tcg_rdr_env, tcg_imports
161 (rdr_env, imports) <- rnImports import_decls ;
163 -- In one-shot mode, record boot-file info in the EPS
164 ifM (isOneShot (hsc_mode hsc_env)) $
165 updateEps_ (\eps -> eps { eps_is_boot = imp_dep_mods imports }) ;
167 -- Update the gbl env
168 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
169 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
171 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
172 -- Fail if there are any errors so far
173 -- The error printing (if needed) takes advantage
174 -- of the tcg_env we have now set
177 -- Load any orphan-module interfaces, so that
178 -- their rules and instance decls will be found
179 loadOrphanModules (imp_orphs imports) ;
181 traceRn (text "rn1a") ;
182 -- Rename and type check the declarations
183 tcg_env <- tcRnSrcDecls local_decls ;
184 setGblEnv tcg_env $ do {
186 traceRn (text "rn3") ;
188 -- Report the use of any deprecated things
189 -- We do this before processsing the export list so
190 -- that we don't bleat about re-exporting a deprecated
191 -- thing (especially via 'module Foo' export item)
192 -- Only uses in the body of the module are complained about
193 reportDeprecations tcg_env ;
195 -- Process the export list
196 exports <- exportsFromAvail (isJust maybe_mod) exports ;
198 {- Jan 04: I don't think this is necessary any more; usage info is derived from tcg_dus
199 -- Get any supporting decls for the exports that have not already
200 -- been sucked in for the declarations in the body of the module.
201 -- (This can happen if something is imported only to be re-exported.)
203 -- Importing these supporting declarations is required
204 -- *only* to gether usage information
205 -- (see comments with MkIface.mkImportInfo for why)
206 -- We don't need the results, but sucking them in may side-effect
207 -- the ExternalPackageState, apart from recording usage
208 mappM (tcLookupGlobal . availName) export_avails ;
211 -- Check whether the entire module is deprecated
212 -- This happens only once per module
213 let { mod_deprecs = checkModDeprec mod_deprec } ;
215 -- Add exports and deprecations to envt
216 let { final_env = tcg_env { tcg_exports = exports,
217 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
218 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
220 -- A module deprecation over-rides the earlier ones
223 -- Report unused names
224 reportUnusedNames final_env ;
226 -- Dump output and return
233 %************************************************************************
235 Type-checking external-core modules
237 %************************************************************************
240 tcRnExtCore :: HscEnv
242 -> IO (Messages, Maybe ModGuts)
243 -- Nothing => some error occurred
245 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
246 -- The decls are IfaceDecls; all names are original names
247 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
249 initTc hsc_env this_mod $ do {
251 let { ldecls = map noLoc decls } ;
253 -- Deal with the type declarations; first bring their stuff
254 -- into scope, then rname them, then type check them
255 (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup ldecls) ;
257 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
258 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
261 rn_decls <- rnTyClDecls ldecls ;
264 -- Dump trace of renaming part
265 rnDump (ppr rn_decls) ;
267 -- Typecheck them all together so that
268 -- any mutually recursive types are done right
269 tcg_env <- checkNoErrs (tcTyAndClassDecls rn_decls) ;
270 -- Make the new type env available to stuff slurped from interface files
272 setGblEnv tcg_env $ do {
274 -- Now the core bindings
275 core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;
279 bndrs = bindersOfBinds core_binds ;
280 my_exports = mkNameSet (map idName bndrs) ;
281 -- ToDo: export the data types also?
283 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
285 mod_guts = ModGuts { mg_module = this_mod,
286 mg_usages = [], -- ToDo: compute usage
287 mg_dir_imps = [], -- ??
288 mg_deps = noDependencies, -- ??
289 mg_exports = my_exports,
290 mg_types = final_type_env,
291 mg_insts = tcg_insts tcg_env,
293 mg_binds = core_binds,
296 mg_rdr_env = emptyGlobalRdrEnv,
297 mg_fix_env = emptyFixityEnv,
298 mg_deprecs = NoDeprecs,
302 tcCoreDump mod_guts ;
307 mkFakeGroup decls -- Rather clumsy; lots of unused fields
308 = HsGroup { hs_tyclds = decls, -- This is the one we want
309 hs_valds = [], hs_fords = [],
310 hs_instds = [], hs_fixds = [], hs_depds = [],
311 hs_ruleds = [], hs_defds = [] }
315 %************************************************************************
317 Type-checking the top level of a module
319 %************************************************************************
322 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
323 -- Returns the variables free in the decls
324 -- Reason: solely to report unused imports and bindings
326 = do { mb_boot_iface <- loadHiBootInterface ;
328 -- Do all the declarations
329 (tc_envs, lie) <- getLIE (tc_rn_src_decls decls) ;
331 -- tcSimplifyTop deals with constant or ambiguous InstIds.
332 -- How could there be ambiguous ones? They can only arise if a
333 -- top-level decl falls under the monomorphism
334 -- restriction, and no subsequent decl instantiates its
335 -- type. (Usually, ambiguous type variables are resolved
336 -- during the generalisation step.)
337 traceTc (text "Tc8") ;
338 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
339 -- Setting the global env exposes the instances to tcSimplifyTop
340 -- Setting the local env exposes the local Ids to tcSimplifyTop,
341 -- so that we get better error messages (monomorphism restriction)
343 -- Backsubstitution. This must be done last.
344 -- Even tcSimplifyTop may do some unification.
345 traceTc (text "Tc9") ;
346 let { (tcg_env, _) = tc_envs ;
347 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
348 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
350 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
353 let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
355 -- Compre the hi-boot iface (if any) with the real thing
356 checkHiBootIface final_type_env mb_boot_iface ;
358 -- Make the new type env available to stuff slurped from interface files
359 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
361 return (tcg_env { tcg_type_env = final_type_env,
362 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' })
365 tc_rn_src_decls :: [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
366 -- Loops around dealing with each top level inter-splice group
367 -- in turn, until it's dealt with the entire module
369 = do { let { (first_group, group_tail) = findSplice ds } ;
370 -- If ds is [] we get ([], Nothing)
372 -- Type check the decls up to, but not including, the first splice
373 tc_envs@(tcg_env,tcl_env) <- tcRnGroup first_group ;
375 -- Bale out if errors; for example, error recovery when checking
376 -- the RHS of 'main' can mean that 'main' is not in the envt for
377 -- the subsequent checkMain test
382 -- If there is no splice, we're nearly done
384 Nothing -> do { -- Last thing: check for `main'
385 tcg_env <- checkMain ;
386 return (tcg_env, tcl_env)
389 -- If there's a splice, we must carry on
390 Just (SpliceDecl splice_expr, rest_ds) -> do {
392 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
395 -- Rename the splice expression, and get its supporting decls
396 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
397 failIfErrsM ; -- Don't typecheck if renaming failed
399 -- Execute the splice
400 spliced_decls <- tcSpliceDecls rn_splice_expr ;
402 -- Glue them on the front of the remaining decls and loop
403 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
404 tc_rn_src_decls (spliced_decls ++ rest_ds)
409 %************************************************************************
411 Comparing the hi-boot interface with the real thing
413 %************************************************************************
415 In both one-shot mode and GHCi mode, hi-boot interfaces are demand-loaded
416 into the External Package Table. Once we've typechecked the body of the
417 module, we want to compare what we've found (gathered in a TypeEnv) with
418 the hi-boot stuff in the EPT. We do so here, using the export list of
419 the hi-boot interface as our checklist.
422 checkHiBootIface :: TypeEnv -> Maybe ModIface -> TcM ()
423 -- Compare the hi-boot file for this module (if there is one)
424 -- with the type environment we've just come up with
425 checkHiBootIface env Nothing -- No hi-boot
428 checkHiBootIface env (Just iface)
429 = mapM_ (check_one env) exports
431 exports = [ (mod, availName avail) | (mod,avails) <- mi_exports iface,
434 check_one local_env (mod,occ)
435 = do { name <- lookupOrig mod occ
438 -- Look up the hi-boot one;
439 -- it should jolly well be there (else GHC bug)
440 ; case lookupTypeEnv (eps_PTE eps) name of {
441 Nothing -> pprPanic "checkHiBootIface" (ppr name) ;
444 -- Look it up in the local type env
445 -- It should be there, but it's a programmer error if not
446 case lookupTypeEnv local_env name of
447 Nothing -> addErrTc (missingBootThing boot_thing)
448 Just real_thing -> check_thing boot_thing real_thing
452 check_thing (ATyCon boot_tc) (ATyCon real_tc)
453 | isSynTyCon boot_tc && isSynTyCon real_tc,
454 defn1 `tcEqType` substTyWith tvs2 (mkTyVarTys tvs1) defn2
457 | tyConKind boot_tc == tyConKind real_tc
460 (tvs1, defn1) = getSynTyConDefn boot_tc
461 (tvs2, defn2) = getSynTyConDefn boot_tc
463 check_thing (AnId boot_id) (AnId real_id)
464 | idType boot_id `tcEqType` idType real_id
467 check_thing boot_thing real_thing -- Default case; failure
468 = addErrAt (srcLocSpan (getSrcLoc real_thing))
469 (bootMisMatch real_thing)
472 missingBootThing thing
473 = ppr thing <+> ptext SLIT("is defined in the hi-boot file, but not in the module")
475 = ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hi-boot file")
479 %************************************************************************
481 Type-checking the top level of a module
483 %************************************************************************
485 tcRnGroup takes a bunch of top-level source-code declarations, and
487 * gets supporting declarations from interface files
490 * and augments the TcGblEnv with the results
492 In Template Haskell it may be called repeatedly for each group of
493 declarations. It expects there to be an incoming TcGblEnv in the
494 monad; it augments it and returns the new TcGblEnv.
497 tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
498 -- Returns the variables free in the decls, for unused-binding reporting
500 = do { -- Rename the declarations
501 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
502 setGblEnv tcg_env $ do {
504 -- Typecheck the declarations
505 tcTopSrcDecls rn_decls
508 ------------------------------------------------
509 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
511 = do { -- Bring top level binders into scope
512 (rdr_env, imports) <- importsFromLocalDecls group ;
513 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
514 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
517 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
518 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
520 -- Rename the source decls
521 (tcg_env, rn_decls) <- rnSrcDecls group ;
524 -- Dump trace of renaming part
525 rnDump (ppr rn_decls) ;
527 return (tcg_env, rn_decls)
530 ------------------------------------------------
531 tcTopSrcDecls :: HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
533 (HsGroup { hs_tyclds = tycl_decls,
534 hs_instds = inst_decls,
535 hs_fords = foreign_decls,
536 hs_defds = default_decls,
537 hs_ruleds = rule_decls,
538 hs_valds = val_binds })
539 = do { -- Type-check the type and class decls, and all imported decls
540 -- The latter come in via tycl_decls
541 traceTc (text "Tc2") ;
543 tcg_env <- checkNoErrs (tcTyAndClassDecls tycl_decls) ;
544 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
545 -- an error we'd better stop now, to avoid a cascade
547 -- Make these type and class decls available to stuff slurped from interface files
548 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
551 setGblEnv tcg_env $ do {
552 -- Source-language instances, including derivings,
553 -- and import the supporting declarations
554 traceTc (text "Tc3") ;
555 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
556 setGblEnv tcg_env $ do {
558 -- Foreign import declarations next. No zonking necessary
559 -- here; we can tuck them straight into the global environment.
560 traceTc (text "Tc4") ;
561 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
562 tcExtendGlobalValEnv fi_ids $ do {
564 -- Default declarations
565 traceTc (text "Tc4a") ;
566 default_tys <- tcDefaults default_decls ;
567 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
569 -- Value declarations next
570 -- We also typecheck any extra binds that came out
571 -- of the "deriving" process (deriv_binds)
572 traceTc (text "Tc5") ;
573 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
574 setLclTypeEnv lcl_env $ do {
576 -- Second pass over class and instance declarations,
577 traceTc (text "Tc6") ;
578 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
579 showLIE (text "after instDecls2") ;
582 -- They need to be zonked, so we return them
583 traceTc (text "Tc7") ;
584 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
587 rules <- tcRules rule_decls ;
590 traceTc (text "Tc7a") ;
591 tcg_env <- getGblEnv ;
592 let { all_binds = tc_val_binds `unionBags`
593 inst_binds `unionBags`
596 -- Extend the GblEnv with the (as yet un-zonked)
597 -- bindings, rules, foreign decls
598 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
599 tcg_rules = tcg_rules tcg_env ++ rules,
600 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
601 return (tcg_env', lcl_env)
606 %************************************************************************
610 %************************************************************************
614 = do { ghci_mode <- getGhciMode ;
615 tcg_env <- getGblEnv ;
617 mb_main_mod <- readMutVar v_MainModIs ;
618 mb_main_fn <- readMutVar v_MainFunIs ;
619 let { main_mod = case mb_main_mod of {
620 Just mod -> mkModuleName mod ;
621 Nothing -> mAIN_Name } ;
622 main_fn = case mb_main_fn of {
623 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
624 Nothing -> main_RDR_Unqual } } ;
626 check_main ghci_mode tcg_env main_mod main_fn
630 check_main ghci_mode tcg_env main_mod main_fn
631 -- If we are in module Main, check that 'main' is defined.
632 -- It may be imported from another module!
634 -- ToDo: We have to return the main_name separately, because it's a
635 -- bona fide 'use', and should be recorded as such, but the others
638 -- Blimey: a whole page of code to do this...
639 | mod_name /= main_mod
643 = addErrCtxt mainCtxt $
644 do { mb_main <- lookupSrcOcc_maybe main_fn
645 -- Check that 'main' is in scope
646 -- It might be imported from another module!
648 Nothing -> do { complain_no_main
651 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
652 -- :Main.main :: IO () = runIO main
654 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
657 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
658 main_bind = noLoc (VarBind root_main_id main_expr) }
660 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
662 tcg_dus = tcg_dus tcg_env
663 `plusDU` usesOnly (unitFV main_name)
667 mod_name = moduleName (tcg_mod tcg_env)
669 complain_no_main | ghci_mode == Interactive = return ()
670 | otherwise = failWithTc noMainMsg
671 -- In interactive mode, don't worry about the absence of 'main'
672 -- In other modes, fail altogether, so that we don't go on
673 -- and complain a second time when processing the export list.
675 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
676 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
677 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
681 %*********************************************************
685 %*********************************************************
689 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
690 setInteractiveContext icxt thing_inside
691 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
692 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
693 tcg_type_env = ic_type_env icxt}) $
694 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
701 -> InteractiveContext
703 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
704 -- The returned [Name] is the same as the input except for
705 -- ExprStmt, in which case the returned [Name] is [itName]
707 -- The returned TypecheckedHsExpr is of type IO [ () ],
708 -- a list of the bound values, coerced to ().
710 tcRnStmt hsc_env ictxt rdr_stmt
711 = initTcPrintErrors hsc_env iNTERACTIVE $
712 setInteractiveContext ictxt $ do {
714 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
715 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
716 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
719 -- The real work is done here
720 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
722 traceTc (text "tcs 1") ;
723 let { -- Make all the bound ids "global" ids, now that
724 -- they're notionally top-level bindings. This is
725 -- important: otherwise when we come to compile an expression
726 -- using these ids later, the byte code generator will consider
727 -- the occurrences to be free rather than global.
728 global_ids = map (globaliseId VanillaGlobal) bound_ids ;
730 -- Update the interactive context
731 rn_env = ic_rn_local_env ictxt ;
732 type_env = ic_type_env ictxt ;
734 bound_names = map idName global_ids ;
735 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
737 -- Remove any shadowed bindings from the type_env;
738 -- they are inaccessible but might, I suppose, cause
739 -- a space leak if we leave them there
740 shadowed = [ n | name <- bound_names,
741 let rdr_name = mkRdrUnqual (nameOccName name),
742 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
744 filtered_type_env = delListFromNameEnv type_env shadowed ;
745 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
747 new_ic = ictxt { ic_rn_local_env = new_rn_env,
748 ic_type_env = new_type_env }
751 dumpOptTcRn Opt_D_dump_tc
752 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
753 text "Typechecked expr" <+> ppr tc_expr]) ;
755 returnM (new_ic, bound_names, tc_expr)
760 Here is the grand plan, implemented in tcUserStmt
762 What you type The IO [HValue] that hscStmt returns
763 ------------- ------------------------------------
764 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
767 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
770 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
771 [NB: result not printed] bindings: [it]
773 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
774 result showable) bindings: [it]
776 expr (of non-IO type,
777 result not showable) ==> error
781 ---------------------------
782 tcUserStmt :: LStmt Name -> TcM ([Id], LHsExpr Id)
783 tcUserStmt (L _ (ExprStmt expr _))
784 = newUnique `thenM` \ uniq ->
786 fresh_it = itName uniq
787 the_bind = noLoc $ FunBind (noLoc fresh_it) False
788 (mkMatchGroup [mkSimpleMatch [] expr])
790 tryTcLIE_ (do { -- Try this if the other fails
791 traceTc (text "tcs 1b") ;
793 nlLetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive],
794 nlExprStmt (nlHsApp (nlHsVar printName)
797 (do { -- Try this first
798 traceTc (text "tcs 1a") ;
799 tc_stmts [nlBindStmt (nlVarPat fresh_it) expr] })
801 tcUserStmt stmt = tc_stmts [stmt]
803 ---------------------------
805 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
807 ret_ty = mkListTy unitTy ;
808 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
810 names = map unLoc (collectStmtsBinders stmts) ;
812 stmt_ctxt = SC { sc_what = DoExpr,
814 sc_body = check_body,
817 infer_rhs rhs = do { (rhs', rhs_ty) <- tcInferRho rhs
818 ; [pat_ty] <- unifyTyConApp ioTyCon rhs_ty
819 ; return (rhs', pat_ty) } ;
820 check_body body = tcCheckRho body io_ret_ty ;
822 -- mk_return builds the expression
823 -- returnIO @ [()] [coerce () x, .., coerce () z]
825 -- Despite the inconvenience of building the type applications etc,
826 -- this *has* to be done in type-annotated post-typecheck form
827 -- because we are going to return a list of *polymorphic* values
828 -- coerced to type (). If we built a *source* stmt
829 -- return [coerce x, ..., coerce z]
830 -- then the type checker would instantiate x..z, and we wouldn't
831 -- get their *polymorphic* values. (And we'd get ambiguity errs
832 -- if they were overloaded, since they aren't applied to anything.)
833 mk_return ret_id ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
834 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
835 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
838 io_ty = mkTyConApp ioTyCon []
841 -- OK, we're ready to typecheck the stmts
842 traceTc (text "tcs 2") ;
843 ((ids, tc_expr), lie) <- getLIE $ do {
844 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
846 -- Look up the names right in the middle,
847 -- where they will all be in scope
848 ids <- mappM tcLookupId names ;
849 ret_id <- tcLookupId returnIOName ; -- return @ IO
850 return (ids, [nlResultStmt (mk_return ret_id ids)]) } ;
852 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
853 return (ids, noLoc (HsDo DoExpr tc_stmts io_ids io_ret_ty))
856 -- Simplify the context right here, so that we fail
857 -- if there aren't enough instances. Notably, when we see
859 -- we use recoverTc_ to try it <- e
860 -- and then let it = e
861 -- It's the simplify step that rejects the first.
862 traceTc (text "tcs 3") ;
863 const_binds <- tcSimplifyInteractive lie ;
865 -- Build result expression and zonk it
866 let { expr = mkHsLet const_binds tc_expr } ;
867 zonked_expr <- zonkTopLExpr expr ;
868 zonked_ids <- zonkTopBndrs ids ;
870 -- None of the Ids should be of unboxed type, because we
871 -- cast them all to HValues in the end!
872 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
874 return (zonked_ids, zonked_expr)
877 combine stmt (ids, stmts) = (ids, stmt:stmts)
878 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
879 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
883 tcRnExpr just finds the type of an expression
887 -> InteractiveContext
890 tcRnExpr hsc_env ictxt rdr_expr
891 = initTcPrintErrors hsc_env iNTERACTIVE $
892 setInteractiveContext ictxt $ do {
894 (rn_expr, fvs) <- rnLExpr rdr_expr ;
897 -- Now typecheck the expression;
898 -- it might have a rank-2 type (e.g. :t runST)
899 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
900 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
901 tcSimplifyInteractive lie_top ;
903 let { all_expr_ty = mkForAllTys qtvs $
904 mkFunTys (map idType dict_ids) $
906 zonkTcType all_expr_ty
909 smpl_doc = ptext SLIT("main expression")
912 tcRnType just finds the kind of a type
916 -> InteractiveContext
919 tcRnType hsc_env ictxt rdr_type
920 = initTcPrintErrors hsc_env iNTERACTIVE $
921 setInteractiveContext ictxt $ do {
923 rn_type <- rnLHsType doc rdr_type ;
926 -- Now kind-check the type
927 (ty', kind) <- kcHsType rn_type ;
931 doc = ptext SLIT("In GHCi input")
937 %************************************************************************
939 More GHCi stuff, to do with browsing and getting info
941 %************************************************************************
945 mkExportEnv :: HscEnv -> [ModuleName] -- Expose these modules' exports only
947 mkExportEnv hsc_env exports
948 = do { mb_envs <- initTcPrintErrors hsc_env iNTERACTIVE $
949 mappM getModuleExports exports
951 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
952 Nothing -> return emptyGlobalRdrEnv
953 -- Some error; initTc will have printed it
956 getModuleExports :: ModuleName -> TcM GlobalRdrEnv
958 = do { iface <- load_iface mod
959 ; loadOrphanModules (dep_orphs (mi_deps iface))
960 -- Load any orphan-module interfaces,
961 -- so their instances are visible
962 ; avails <- exportsToAvails (mi_exports iface)
963 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
964 | avail <- avails, name <- availNames avail ] }
965 ; returnM (mkGlobalRdrEnv gres) }
967 vanillaProv :: ModuleName -> Provenance
968 -- We're building a GlobalRdrEnv as if the user imported
969 -- all the specified modules into the global interactive module
970 vanillaProv mod = Imported [ImportSpec mod mod False
971 (srcLocSpan interactiveSrcLoc)] False
977 -> InteractiveContext
978 -> ModuleName -- Module to inspect
979 -> Bool -- Grab just the exports, or the whole toplev
980 -> IO (Maybe [IfaceDecl])
982 getModuleContents hsc_env ictxt mod exports_only
983 = initTcPrintErrors hsc_env iNTERACTIVE (get_mod_contents exports_only)
985 get_mod_contents exports_only
986 | not exports_only -- We want the whole top-level type env
987 -- so it had better be a home module
989 ; case lookupModuleEnvByName hpt mod of
990 Just mod_info -> return (map toIfaceDecl $
993 md_types (hm_details mod_info))
994 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
995 -- This is a system error; the module should be in the HPT
998 | otherwise -- Want the exports only
999 = do { iface <- load_iface mod
1000 ; avails <- exportsToAvails (mi_exports iface)
1001 ; mappM get_decl avails
1005 = do { thing <- tcLookupGlobal (availName avail)
1006 ; return (filter_decl (availOccs avail) (toIfaceDecl thing)) }
1008 ---------------------
1009 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
1010 = decl { ifSigs = filter (keep_sig occs) sigs }
1011 filter_decl occs decl@(IfaceData {ifCons = IfDataTyCon th cons})
1012 = decl { ifCons = IfDataTyCon th (filter (keep_con occs) cons) }
1013 filter_decl occs decl@(IfaceData {ifCons = IfNewTyCon con})
1014 | keep_con occs con = decl
1015 | otherwise = decl {ifCons = IfAbstractTyCon} -- Hmm?
1016 filter_decl occs decl
1019 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
1020 keep_con occs con = ifConOcc con `elem` occs
1022 availOccs avail = map nameOccName (availNames avail)
1024 wantToSee (AnId id) = not (isImplicitId id)
1025 wantToSee (ADataCon _) = False -- They'll come via their TyCon
1028 ---------------------
1029 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
1031 doc = ptext SLIT("context for compiling statements")
1033 ---------------------
1034 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1035 <+> quotes (ppr mod)
1039 tcRnGetInfo :: HscEnv
1040 -> InteractiveContext
1042 -> IO (Maybe [(IfaceDecl,
1044 [(IfaceInst, SrcLoc)])])
1045 -- Used to implemnent :info in GHCi
1047 -- Look up a RdrName and return all the TyThings it might be
1048 -- A capitalised RdrName is given to us in the DataName namespace,
1049 -- but we want to treat it as *both* a data constructor
1050 -- *and* as a type or class constructor;
1051 -- hence the call to dataTcOccs, and we return up to two results
1052 tcRnGetInfo hsc_env ictxt rdr_name
1053 = initTcPrintErrors hsc_env iNTERACTIVE $
1054 setInteractiveContext ictxt $ do {
1056 -- If the identifier is a constructor (begins with an
1057 -- upper-case letter), then we need to consider both
1058 -- constructor and type class identifiers.
1059 let { rdr_names = dataTcOccs rdr_name } ;
1061 -- results :: [(Messages, Maybe Name)]
1062 results <- mapM (tryTc . lookupOccRn) rdr_names ;
1064 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1065 -- The successful lookups will be (Just name)
1066 let { (warns_s, good_names) = unzip [ (msgs, name)
1067 | (msgs, Just name) <- results] ;
1068 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1070 -- Fail if nothing good happened, else add warnings
1071 if null good_names then
1072 -- No lookup succeeded, so
1073 -- pick the first error message and report it
1074 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1075 -- while the other is "X is not in scope",
1076 -- we definitely want the former; but we might pick the latter
1077 do { addMessages (head errs_s) ; failM }
1078 else -- Add deprecation warnings
1079 mapM_ addMessages warns_s ;
1081 -- And lookup up the entities, avoiding duplicates, which arise
1082 -- because constructors and record selectors are represented by
1083 -- their parent declaration
1084 let { do_one name = do { thing <- tcLookupGlobal name
1085 ; let decl = toIfaceDecl thing
1086 ; fixity <- lookupFixityRn name
1087 ; insts <- lookupInsts thing
1088 ; return (decl, fixity, getSrcLoc thing,
1089 map mk_inst insts) } ;
1090 -- For the SrcLoc, the 'thing' has better info than
1091 -- the 'name' because getting the former forced the
1092 -- declaration to be loaded into the cache
1093 mk_inst dfun = (dfunToIfaceInst dfun, getSrcLoc dfun) ;
1094 cmp (d1,_,_,_) (d2,_,_,_) = ifName d1 `compare` ifName d2 } ;
1095 results <- mapM do_one good_names ;
1096 return (fst (removeDups cmp results))
1099 lookupInsts :: TyThing -> TcM [DFunId]
1100 lookupInsts (AClass cls)
1101 = do { loadImportedInsts cls [] -- [] means load all instances for cls
1102 ; inst_envs <- tcGetInstEnvs
1103 ; return [df | (_,_,df) <- classInstances inst_envs cls] }
1105 lookupInsts (ATyCon tc)
1106 = do { eps <- getEps -- Load all instances for all classes that are
1107 -- in the type environment (which are all the ones
1108 -- we've seen in any interface file so far
1109 ; mapM_ (\c -> loadImportedInsts c [])
1110 (typeEnvClasses (eps_PTE eps))
1111 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1112 ; return (get home_ie ++ get pkg_ie) }
1114 get ie = [df | (_,_,df) <- instEnvElts ie, relevant df]
1115 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1116 tc_name = tyConName tc
1118 lookupInsts other = return []
1121 toIfaceDecl :: TyThing -> IfaceDecl
1123 = tyThingToIfaceDecl True -- Discard IdInfo
1124 emptyNameSet -- Show data cons
1125 ext_nm (munge thing)
1127 ext_nm n = ExtPkg (nameModuleName n) (nameOccName n)
1129 -- munge transforms a thing to it's "parent" thing
1130 munge (ADataCon dc) = ATyCon (dataConTyCon dc)
1131 munge (AnId id) = case globalIdDetails id of
1132 RecordSelId tc lbl -> ATyCon tc
1133 ClassOpId cls -> AClass cls
1135 munge other_thing = other_thing
1140 %************************************************************************
1144 %************************************************************************
1147 rnDump :: SDoc -> TcRn ()
1148 -- Dump, with a banner, if -ddump-rn
1149 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1151 tcDump :: TcGblEnv -> TcRn ()
1153 = do { dflags <- getDOpts ;
1155 -- Dump short output if -ddump-types or -ddump-tc
1156 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1157 (dumpTcRn short_dump) ;
1159 -- Dump bindings if -ddump-tc
1160 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1163 short_dump = pprTcGblEnv env
1164 full_dump = pprLHsBinds (tcg_binds env)
1165 -- NB: foreign x-d's have undefined's in their types;
1166 -- hence can't show the tc_fords
1169 = do { dflags <- getDOpts ;
1170 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1171 (dumpTcRn (pprModGuts mod_guts)) ;
1173 -- Dump bindings if -ddump-tc
1174 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1176 full_dump = pprCoreBindings (mg_binds mod_guts)
1178 -- It's unpleasant having both pprModGuts and pprModDetails here
1179 pprTcGblEnv :: TcGblEnv -> SDoc
1180 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1181 tcg_insts = dfun_ids,
1183 tcg_imports = imports })
1184 = vcat [ ppr_types dfun_ids type_env
1185 , ppr_insts dfun_ids
1186 , vcat (map ppr rules)
1187 , ppr_gen_tycons (typeEnvTyCons type_env)
1188 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1189 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1191 pprModGuts :: ModGuts -> SDoc
1192 pprModGuts (ModGuts { mg_types = type_env,
1194 = vcat [ ppr_types [] type_env,
1198 ppr_types :: [Var] -> TypeEnv -> SDoc
1199 ppr_types dfun_ids type_env
1200 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1202 ids = [id | id <- typeEnvIds type_env, want_sig id]
1203 want_sig id | opt_PprStyle_Debug = True
1204 | otherwise = isLocalId id &&
1205 isExternalName (idName id) &&
1206 not (id `elem` dfun_ids)
1207 -- isLocalId ignores data constructors, records selectors etc.
1208 -- The isExternalName ignores local dictionary and method bindings
1209 -- that the type checker has invented. Top-level user-defined things
1210 -- have External names.
1212 ppr_insts :: [Var] -> SDoc
1213 ppr_insts [] = empty
1214 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1216 ppr_sigs :: [Var] -> SDoc
1218 -- Print type signatures; sort by OccName
1219 = vcat (map ppr_sig (sortLe le_sig ids))
1221 le_sig id1 id2 = getOccName id1 <= getOccName id2
1222 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1224 ppr_rules :: [IdCoreRule] -> SDoc
1225 ppr_rules [] = empty
1226 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1227 nest 4 (pprIdRules rs),
1230 ppr_gen_tycons [] = empty
1231 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1232 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]