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 DataCon ( dataConWrapId )
56 import ErrUtils ( Messages, mkDumpDoc, showPass )
57 import Id ( mkExportedLocalId, isLocalId, idName, idType )
59 import Module ( mkHomeModule, mkModuleName, moduleName, moduleEnvElts )
60 import OccName ( mkVarOcc )
61 import Name ( Name, isExternalName, getSrcLoc, getOccName )
63 import TyCon ( tyConHasGenerics, isSynTyCon, getSynTyConDefn, tyConKind )
64 import SrcLoc ( srcLocSpan, Located(..), noLoc )
66 import HscTypes ( ModGuts(..), HscEnv(..), ExternalPackageState(..),
67 GhciMode(..), noDependencies, isOneShot,
68 Deprecs( NoDeprecs ), ModIface(..), plusDeprecs,
69 ForeignStubs(NoStubs), TyThing(..),
70 TypeEnv, lookupTypeEnv,
71 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
72 emptyFixityEnv, availName
75 import HsSyn ( HsStmtContext(..), Stmt(..), HsExpr(..), HsBindGroup(..),
76 LStmt, LHsExpr, LHsType, mkMatchGroup,
77 collectStmtsBinders, mkSimpleMatch, placeHolderType,
78 nlLetStmt, nlExprStmt, nlBindStmt, nlResultStmt, nlVarPat )
79 import RdrName ( GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
80 Provenance(..), ImportSpec(..),
81 lookupLocalRdrEnv, extendLocalRdrEnv )
82 import RnSource ( addTcgDUs )
83 import TcHsSyn ( mkHsLet, zonkTopLExpr, zonkTopBndrs )
84 import TcHsType ( kcHsType )
85 import TcExpr ( tcCheckRho )
86 import TcIface ( loadImportedInsts )
87 import TcMType ( zonkTcType, zonkQuantifiedTyVar )
88 import TcUnify ( unifyTyConApp )
89 import TcMatches ( tcStmtsAndThen, TcStmtCtxt(..) )
90 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
91 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType,
92 isUnLiftedType, tyClsNamesOfDFunHead )
93 import TcEnv ( tcLookupTyCon, tcLookupId, tcLookupGlobal )
94 import RnTypes ( rnLHsType )
95 import Inst ( tcStdSyntaxName, tcGetInstEnvs )
96 import InstEnv ( DFunId, classInstances, instEnvElts )
97 import RnExpr ( rnStmts, rnLExpr )
98 import RnNames ( exportsToAvails )
99 import LoadIface ( loadSrcInterface )
100 import IfaceSyn ( IfaceDecl(..), IfaceClassOp(..), IfaceConDecl(..),
101 IfaceExtName(..), IfaceConDecls(..), IfaceInst(..),
102 tyThingToIfaceDecl, dfunToIfaceInst )
103 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
104 import Id ( Id, isImplicitId, globalIdDetails )
105 import MkId ( unsafeCoerceId )
106 import DataCon ( dataConTyCon )
107 import TyCon ( tyConName )
108 import TysWiredIn ( mkListTy, unitTy )
109 import IdInfo ( GlobalIdDetails(..) )
110 import SrcLoc ( interactiveSrcLoc, unLoc )
112 import Var ( globaliseId )
113 import Name ( nameOccName, nameModuleName )
114 import NameEnv ( delListFromNameEnv )
115 import PrelNames ( iNTERACTIVE, ioTyConName, printName, monadNames, itName, returnIOName )
116 import Module ( ModuleName, lookupModuleEnvByName )
117 import HscTypes ( InteractiveContext(..), ExternalPackageState( eps_PTE ),
118 HomeModInfo(..), typeEnvElts, typeEnvClasses,
119 availNames, icPrintUnqual,
120 ModDetails(..), Dependencies(..) )
121 import BasicTypes ( RecFlag(..), Fixity )
122 import Bag ( unitBag )
123 import ListSetOps ( removeDups )
124 import Panic ( ghcError, GhcException(..) )
125 import SrcLoc ( SrcLoc )
128 import FastString ( mkFastString )
129 import Util ( sortLe )
130 import Bag ( unionBags, snocBag )
132 import Maybe ( isJust )
137 %************************************************************************
139 Typecheck and rename a module
141 %************************************************************************
146 -> Located (HsModule RdrName)
147 -> IO (Messages, Maybe TcGblEnv)
149 tcRnModule hsc_env (L loc (HsModule maybe_mod exports
150 import_decls local_decls mod_deprec))
151 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
153 let { this_mod = case maybe_mod of
154 Nothing -> mkHomeModule mAIN_Name
155 -- 'module M where' is omitted
156 Just (L _ mod) -> mod } ;
159 initTc hsc_env this_mod $
161 do { -- Deal with imports; sets tcg_rdr_env, tcg_imports
162 (rdr_env, imports) <- rnImports import_decls ;
164 -- Record boot-file info in the EPS, so that it's
165 -- visible to loadHiBootInterface in tcRnSrcDecls,
166 -- and any other incrementally-performed imports
167 updateEps_ (\eps -> eps { eps_is_boot = imp_dep_mods imports }) ;
169 -- Update the gbl env
170 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
171 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
173 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
174 -- Fail if there are any errors so far
175 -- The error printing (if needed) takes advantage
176 -- of the tcg_env we have now set
179 -- Load any orphan-module interfaces, so that
180 -- their rules and instance decls will be found
181 loadOrphanModules (imp_orphs imports) ;
183 traceRn (text "rn1a") ;
184 -- Rename and type check the declarations
185 tcg_env <- tcRnSrcDecls local_decls ;
186 setGblEnv tcg_env $ do {
188 traceRn (text "rn3") ;
190 -- Report the use of any deprecated things
191 -- We do this before processsing the export list so
192 -- that we don't bleat about re-exporting a deprecated
193 -- thing (especially via 'module Foo' export item)
194 -- Only uses in the body of the module are complained about
195 reportDeprecations tcg_env ;
197 -- Process the export list
198 exports <- exportsFromAvail (isJust maybe_mod) exports ;
200 {- Jan 04: I don't think this is necessary any more; usage info is derived from tcg_dus
201 -- Get any supporting decls for the exports that have not already
202 -- been sucked in for the declarations in the body of the module.
203 -- (This can happen if something is imported only to be re-exported.)
205 -- Importing these supporting declarations is required
206 -- *only* to gether usage information
207 -- (see comments with MkIface.mkImportInfo for why)
208 -- We don't need the results, but sucking them in may side-effect
209 -- the ExternalPackageState, apart from recording usage
210 mappM (tcLookupGlobal . availName) export_avails ;
213 -- Check whether the entire module is deprecated
214 -- This happens only once per module
215 let { mod_deprecs = checkModDeprec mod_deprec } ;
217 -- Add exports and deprecations to envt
218 let { final_env = tcg_env { tcg_exports = exports,
219 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
220 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
222 -- A module deprecation over-rides the earlier ones
225 -- Report unused names
226 reportUnusedNames final_env ;
228 -- Dump output and return
235 %************************************************************************
237 Type-checking external-core modules
239 %************************************************************************
242 tcRnExtCore :: HscEnv
244 -> IO (Messages, Maybe ModGuts)
245 -- Nothing => some error occurred
247 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
248 -- The decls are IfaceDecls; all names are original names
249 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
251 initTc hsc_env this_mod $ do {
253 let { ldecls = map noLoc decls } ;
255 -- Deal with the type declarations; first bring their stuff
256 -- into scope, then rname them, then type check them
257 (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup ldecls) ;
259 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
260 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
263 rn_decls <- rnTyClDecls ldecls ;
266 -- Dump trace of renaming part
267 rnDump (ppr rn_decls) ;
269 -- Typecheck them all together so that
270 -- any mutually recursive types are done right
271 tcg_env <- checkNoErrs (tcTyAndClassDecls [{- no boot names -}] rn_decls) ;
272 -- Make the new type env available to stuff slurped from interface files
274 setGblEnv tcg_env $ do {
276 -- Now the core bindings
277 core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;
281 bndrs = bindersOfBinds core_binds ;
282 my_exports = mkNameSet (map idName bndrs) ;
283 -- ToDo: export the data types also?
285 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
287 mod_guts = ModGuts { mg_module = this_mod,
288 mg_usages = [], -- ToDo: compute usage
289 mg_dir_imps = [], -- ??
290 mg_deps = noDependencies, -- ??
291 mg_exports = my_exports,
292 mg_types = final_type_env,
293 mg_insts = tcg_insts tcg_env,
295 mg_binds = core_binds,
298 mg_rdr_env = emptyGlobalRdrEnv,
299 mg_fix_env = emptyFixityEnv,
300 mg_deprecs = NoDeprecs,
304 tcCoreDump mod_guts ;
309 mkFakeGroup decls -- Rather clumsy; lots of unused fields
310 = HsGroup { hs_tyclds = decls, -- This is the one we want
311 hs_valds = [], hs_fords = [],
312 hs_instds = [], hs_fixds = [], hs_depds = [],
313 hs_ruleds = [], hs_defds = [] }
317 %************************************************************************
319 Type-checking the top level of a module
321 %************************************************************************
324 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
325 -- Returns the variables free in the decls
326 -- Reason: solely to report unused imports and bindings
328 = do { boot_names <- loadHiBootInterface ;
330 -- Do all the declarations
331 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_names decls) ;
333 -- tcSimplifyTop deals with constant or ambiguous InstIds.
334 -- How could there be ambiguous ones? They can only arise if a
335 -- top-level decl falls under the monomorphism
336 -- restriction, and no subsequent decl instantiates its
337 -- type. (Usually, ambiguous type variables are resolved
338 -- during the generalisation step.)
339 traceTc (text "Tc8") ;
340 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
341 -- Setting the global env exposes the instances to tcSimplifyTop
342 -- Setting the local env exposes the local Ids to tcSimplifyTop,
343 -- so that we get better error messages (monomorphism restriction)
345 -- Backsubstitution. This must be done last.
346 -- Even tcSimplifyTop may do some unification.
347 traceTc (text "Tc9") ;
348 let { (tcg_env, _) = tc_envs ;
349 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
350 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
352 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
355 let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
357 -- Compre the hi-boot iface (if any) with the real thing
358 checkHiBootIface final_type_env boot_names ;
360 -- Make the new type env available to stuff slurped from interface files
361 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
363 return (tcg_env { tcg_type_env = final_type_env,
364 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' })
367 tc_rn_src_decls :: [Name] -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
368 -- Loops around dealing with each top level inter-splice group
369 -- in turn, until it's dealt with the entire module
370 tc_rn_src_decls boot_names ds
371 = do { let { (first_group, group_tail) = findSplice ds } ;
372 -- If ds is [] we get ([], Nothing)
374 -- Type check the decls up to, but not including, the first splice
375 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_names first_group ;
377 -- Bale out if errors; for example, error recovery when checking
378 -- the RHS of 'main' can mean that 'main' is not in the envt for
379 -- the subsequent checkMain test
384 -- If there is no splice, we're nearly done
386 Nothing -> do { -- Last thing: check for `main'
387 tcg_env <- checkMain ;
388 return (tcg_env, tcl_env)
391 -- If there's a splice, we must carry on
392 Just (SpliceDecl splice_expr, rest_ds) -> do {
394 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
397 -- Rename the splice expression, and get its supporting decls
398 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
399 failIfErrsM ; -- Don't typecheck if renaming failed
401 -- Execute the splice
402 spliced_decls <- tcSpliceDecls rn_splice_expr ;
404 -- Glue them on the front of the remaining decls and loop
405 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
406 tc_rn_src_decls boot_names (spliced_decls ++ rest_ds)
411 %************************************************************************
413 Comparing the hi-boot interface with the real thing
415 %************************************************************************
417 In both one-shot mode and GHCi mode, hi-boot interfaces are demand-loaded
418 into the External Package Table. Once we've typechecked the body of the
419 module, we want to compare what we've found (gathered in a TypeEnv) with
420 the hi-boot stuff in the EPT. We do so here, using the export list of
421 the hi-boot interface as our checklist.
424 checkHiBootIface :: TypeEnv -> [Name] -> TcM ()
425 -- Compare the hi-boot file for this module (if there is one)
426 -- with the type environment we've just come up with
427 -- In the common case where there is no hi-boot file, the list
428 -- of boot_names is empty.
429 checkHiBootIface env boot_names
430 = mapM_ (check_one env) boot_names
433 check_one local_env name
436 -- Look up the hi-boot one;
437 -- it should jolly well be there (else GHC bug)
438 ; case lookupTypeEnv (eps_PTE eps) name of {
439 Nothing -> pprPanic "checkHiBootIface" (ppr name) ;
442 -- Look it up in the local type env
443 -- It should be there, but it's a programmer error if not
444 case lookupTypeEnv local_env name of
445 Nothing -> addErrTc (missingBootThing boot_thing)
446 Just real_thing -> check_thing boot_thing real_thing
450 check_thing (ATyCon boot_tc) (ATyCon real_tc)
451 | isSynTyCon boot_tc && isSynTyCon real_tc,
452 defn1 `tcEqType` substTyWith tvs2 (mkTyVarTys tvs1) defn2
455 | tyConKind boot_tc == tyConKind real_tc
458 (tvs1, defn1) = getSynTyConDefn boot_tc
459 (tvs2, defn2) = getSynTyConDefn boot_tc
461 check_thing (AnId boot_id) (AnId real_id)
462 | idType boot_id `tcEqType` idType real_id
465 check_thing (ADataCon dc1) (ADataCon dc2)
466 | idType (dataConWrapId dc1) `tcEqType` idType (dataConWrapId dc2)
469 -- Can't declare a class in a hi-boot file
471 check_thing boot_thing real_thing -- Default case; failure
472 = addErrAt (srcLocSpan (getSrcLoc real_thing))
473 (bootMisMatch real_thing)
476 missingBootThing thing
477 = ppr thing <+> ptext SLIT("is defined in the hi-boot file, but not in the module")
479 = ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hi-boot file")
483 %************************************************************************
485 Type-checking the top level of a module
487 %************************************************************************
489 tcRnGroup takes a bunch of top-level source-code declarations, and
491 * gets supporting declarations from interface files
494 * and augments the TcGblEnv with the results
496 In Template Haskell it may be called repeatedly for each group of
497 declarations. It expects there to be an incoming TcGblEnv in the
498 monad; it augments it and returns the new TcGblEnv.
501 tcRnGroup :: [Name] -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
502 -- Returns the variables free in the decls, for unused-binding reporting
503 tcRnGroup boot_names decls
504 = do { -- Rename the declarations
505 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
506 setGblEnv tcg_env $ do {
508 -- Typecheck the declarations
509 tcTopSrcDecls boot_names rn_decls
512 ------------------------------------------------
513 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
515 = do { -- Bring top level binders into scope
516 (rdr_env, imports) <- importsFromLocalDecls group ;
517 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
518 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
521 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
522 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
524 -- Rename the source decls
525 (tcg_env, rn_decls) <- rnSrcDecls group ;
528 -- Dump trace of renaming part
529 rnDump (ppr rn_decls) ;
531 return (tcg_env, rn_decls)
534 ------------------------------------------------
535 tcTopSrcDecls :: [Name] -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
536 tcTopSrcDecls boot_names
537 (HsGroup { hs_tyclds = tycl_decls,
538 hs_instds = inst_decls,
539 hs_fords = foreign_decls,
540 hs_defds = default_decls,
541 hs_ruleds = rule_decls,
542 hs_valds = val_binds })
543 = do { -- Type-check the type and class decls, and all imported decls
544 -- The latter come in via tycl_decls
545 traceTc (text "Tc2") ;
547 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_names tycl_decls) ;
548 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
549 -- an error we'd better stop now, to avoid a cascade
551 -- Make these type and class decls available to stuff slurped from interface files
552 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
555 setGblEnv tcg_env $ do {
556 -- Source-language instances, including derivings,
557 -- and import the supporting declarations
558 traceTc (text "Tc3") ;
559 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
560 setGblEnv tcg_env $ do {
562 -- Foreign import declarations next. No zonking necessary
563 -- here; we can tuck them straight into the global environment.
564 traceTc (text "Tc4") ;
565 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
566 tcExtendGlobalValEnv fi_ids $ do {
568 -- Default declarations
569 traceTc (text "Tc4a") ;
570 default_tys <- tcDefaults default_decls ;
571 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
573 -- Value declarations next
574 -- We also typecheck any extra binds that came out
575 -- of the "deriving" process (deriv_binds)
576 traceTc (text "Tc5") ;
577 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
578 setLclTypeEnv lcl_env $ do {
580 -- Second pass over class and instance declarations,
581 traceTc (text "Tc6") ;
582 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
583 showLIE (text "after instDecls2") ;
586 -- They need to be zonked, so we return them
587 traceTc (text "Tc7") ;
588 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
591 rules <- tcRules rule_decls ;
594 traceTc (text "Tc7a") ;
595 tcg_env <- getGblEnv ;
596 let { all_binds = tc_val_binds `unionBags`
597 inst_binds `unionBags`
600 -- Extend the GblEnv with the (as yet un-zonked)
601 -- bindings, rules, foreign decls
602 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
603 tcg_rules = tcg_rules tcg_env ++ rules,
604 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
605 return (tcg_env', lcl_env)
610 %************************************************************************
614 %************************************************************************
618 = do { ghci_mode <- getGhciMode ;
619 tcg_env <- getGblEnv ;
621 mb_main_mod <- readMutVar v_MainModIs ;
622 mb_main_fn <- readMutVar v_MainFunIs ;
623 let { main_mod = case mb_main_mod of {
624 Just mod -> mkModuleName mod ;
625 Nothing -> mAIN_Name } ;
626 main_fn = case mb_main_fn of {
627 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
628 Nothing -> main_RDR_Unqual } } ;
630 check_main ghci_mode tcg_env main_mod main_fn
634 check_main ghci_mode tcg_env main_mod main_fn
635 -- If we are in module Main, check that 'main' is defined.
636 -- It may be imported from another module!
638 -- ToDo: We have to return the main_name separately, because it's a
639 -- bona fide 'use', and should be recorded as such, but the others
642 -- Blimey: a whole page of code to do this...
643 | mod_name /= main_mod
647 = addErrCtxt mainCtxt $
648 do { mb_main <- lookupSrcOcc_maybe main_fn
649 -- Check that 'main' is in scope
650 -- It might be imported from another module!
652 Nothing -> do { complain_no_main
655 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
656 -- :Main.main :: IO () = runIO main
658 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
661 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
662 main_bind = noLoc (VarBind root_main_id main_expr) }
664 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
666 tcg_dus = tcg_dus tcg_env
667 `plusDU` usesOnly (unitFV main_name)
671 mod_name = moduleName (tcg_mod tcg_env)
673 complain_no_main | ghci_mode == Interactive = return ()
674 | otherwise = failWithTc noMainMsg
675 -- In interactive mode, don't worry about the absence of 'main'
676 -- In other modes, fail altogether, so that we don't go on
677 -- and complain a second time when processing the export list.
679 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
680 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
681 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
685 %*********************************************************
689 %*********************************************************
693 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
694 setInteractiveContext icxt thing_inside
695 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
696 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
697 tcg_type_env = ic_type_env icxt}) $
698 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
705 -> InteractiveContext
707 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
708 -- The returned [Name] is the same as the input except for
709 -- ExprStmt, in which case the returned [Name] is [itName]
711 -- The returned TypecheckedHsExpr is of type IO [ () ],
712 -- a list of the bound values, coerced to ().
714 tcRnStmt hsc_env ictxt rdr_stmt
715 = initTcPrintErrors hsc_env iNTERACTIVE $
716 setInteractiveContext ictxt $ do {
718 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
719 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
720 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
723 -- The real work is done here
724 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
726 traceTc (text "tcs 1") ;
727 let { -- Make all the bound ids "global" ids, now that
728 -- they're notionally top-level bindings. This is
729 -- important: otherwise when we come to compile an expression
730 -- using these ids later, the byte code generator will consider
731 -- the occurrences to be free rather than global.
732 global_ids = map (globaliseId VanillaGlobal) bound_ids ;
734 -- Update the interactive context
735 rn_env = ic_rn_local_env ictxt ;
736 type_env = ic_type_env ictxt ;
738 bound_names = map idName global_ids ;
739 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
741 -- Remove any shadowed bindings from the type_env;
742 -- they are inaccessible but might, I suppose, cause
743 -- a space leak if we leave them there
744 shadowed = [ n | name <- bound_names,
745 let rdr_name = mkRdrUnqual (nameOccName name),
746 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
748 filtered_type_env = delListFromNameEnv type_env shadowed ;
749 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
751 new_ic = ictxt { ic_rn_local_env = new_rn_env,
752 ic_type_env = new_type_env }
755 dumpOptTcRn Opt_D_dump_tc
756 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
757 text "Typechecked expr" <+> ppr tc_expr]) ;
759 returnM (new_ic, bound_names, tc_expr)
764 Here is the grand plan, implemented in tcUserStmt
766 What you type The IO [HValue] that hscStmt returns
767 ------------- ------------------------------------
768 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
771 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
774 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
775 [NB: result not printed] bindings: [it]
777 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
778 result showable) bindings: [it]
780 expr (of non-IO type,
781 result not showable) ==> error
785 ---------------------------
786 tcUserStmt :: LStmt Name -> TcM ([Id], LHsExpr Id)
787 tcUserStmt (L _ (ExprStmt expr _))
788 = newUnique `thenM` \ uniq ->
790 fresh_it = itName uniq
791 the_bind = noLoc $ FunBind (noLoc fresh_it) False
792 (mkMatchGroup [mkSimpleMatch [] expr])
794 tryTcLIE_ (do { -- Try this if the other fails
795 traceTc (text "tcs 1b") ;
797 nlLetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive],
798 nlExprStmt (nlHsApp (nlHsVar printName)
801 (do { -- Try this first
802 traceTc (text "tcs 1a") ;
803 tc_stmts [nlBindStmt (nlVarPat fresh_it) expr] })
805 tcUserStmt stmt = tc_stmts [stmt]
807 ---------------------------
809 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
811 ret_ty = mkListTy unitTy ;
812 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
814 names = map unLoc (collectStmtsBinders stmts) ;
816 stmt_ctxt = SC { sc_what = DoExpr,
818 sc_body = check_body,
821 infer_rhs rhs = do { (rhs', rhs_ty) <- tcInferRho rhs
822 ; [pat_ty] <- unifyTyConApp ioTyCon rhs_ty
823 ; return (rhs', pat_ty) } ;
824 check_body body = tcCheckRho body io_ret_ty ;
826 -- mk_return builds the expression
827 -- returnIO @ [()] [coerce () x, .., coerce () z]
829 -- Despite the inconvenience of building the type applications etc,
830 -- this *has* to be done in type-annotated post-typecheck form
831 -- because we are going to return a list of *polymorphic* values
832 -- coerced to type (). If we built a *source* stmt
833 -- return [coerce x, ..., coerce z]
834 -- then the type checker would instantiate x..z, and we wouldn't
835 -- get their *polymorphic* values. (And we'd get ambiguity errs
836 -- if they were overloaded, since they aren't applied to anything.)
837 mk_return ret_id ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
838 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
839 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
842 io_ty = mkTyConApp ioTyCon []
845 -- OK, we're ready to typecheck the stmts
846 traceTc (text "tcs 2") ;
847 ((ids, tc_expr), lie) <- getLIE $ do {
848 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
850 -- Look up the names right in the middle,
851 -- where they will all be in scope
852 ids <- mappM tcLookupId names ;
853 ret_id <- tcLookupId returnIOName ; -- return @ IO
854 return (ids, [nlResultStmt (mk_return ret_id ids)]) } ;
856 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
857 return (ids, noLoc (HsDo DoExpr tc_stmts io_ids io_ret_ty))
860 -- Simplify the context right here, so that we fail
861 -- if there aren't enough instances. Notably, when we see
863 -- we use recoverTc_ to try it <- e
864 -- and then let it = e
865 -- It's the simplify step that rejects the first.
866 traceTc (text "tcs 3") ;
867 const_binds <- tcSimplifyInteractive lie ;
869 -- Build result expression and zonk it
870 let { expr = mkHsLet const_binds tc_expr } ;
871 zonked_expr <- zonkTopLExpr expr ;
872 zonked_ids <- zonkTopBndrs ids ;
874 -- None of the Ids should be of unboxed type, because we
875 -- cast them all to HValues in the end!
876 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
878 return (zonked_ids, zonked_expr)
881 combine stmt (ids, stmts) = (ids, stmt:stmts)
882 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
883 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
887 tcRnExpr just finds the type of an expression
891 -> InteractiveContext
894 tcRnExpr hsc_env ictxt rdr_expr
895 = initTcPrintErrors hsc_env iNTERACTIVE $
896 setInteractiveContext ictxt $ do {
898 (rn_expr, fvs) <- rnLExpr rdr_expr ;
901 -- Now typecheck the expression;
902 -- it might have a rank-2 type (e.g. :t runST)
903 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
904 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
905 tcSimplifyInteractive lie_top ;
906 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
908 let { all_expr_ty = mkForAllTys qtvs' $
909 mkFunTys (map idType dict_ids) $
911 zonkTcType all_expr_ty
914 smpl_doc = ptext SLIT("main expression")
917 tcRnType just finds the kind of a type
921 -> InteractiveContext
924 tcRnType hsc_env ictxt rdr_type
925 = initTcPrintErrors hsc_env iNTERACTIVE $
926 setInteractiveContext ictxt $ do {
928 rn_type <- rnLHsType doc rdr_type ;
931 -- Now kind-check the type
932 (ty', kind) <- kcHsType rn_type ;
936 doc = ptext SLIT("In GHCi input")
942 %************************************************************************
944 More GHCi stuff, to do with browsing and getting info
946 %************************************************************************
950 mkExportEnv :: HscEnv -> [ModuleName] -- Expose these modules' exports only
952 mkExportEnv hsc_env exports
953 = do { mb_envs <- initTcPrintErrors hsc_env iNTERACTIVE $
954 mappM getModuleExports exports
956 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
957 Nothing -> return emptyGlobalRdrEnv
958 -- Some error; initTc will have printed it
961 getModuleExports :: ModuleName -> TcM GlobalRdrEnv
963 = do { iface <- load_iface mod
964 ; loadOrphanModules (dep_orphs (mi_deps iface))
965 -- Load any orphan-module interfaces,
966 -- so their instances are visible
967 ; avails <- exportsToAvails (mi_exports iface)
968 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
969 | avail <- avails, name <- availNames avail ] }
970 ; returnM (mkGlobalRdrEnv gres) }
972 vanillaProv :: ModuleName -> Provenance
973 -- We're building a GlobalRdrEnv as if the user imported
974 -- all the specified modules into the global interactive module
975 vanillaProv mod = Imported [ImportSpec mod mod False
976 (srcLocSpan interactiveSrcLoc)] False
982 -> InteractiveContext
983 -> ModuleName -- Module to inspect
984 -> Bool -- Grab just the exports, or the whole toplev
985 -> IO (Maybe [IfaceDecl])
987 getModuleContents hsc_env ictxt mod exports_only
988 = initTcPrintErrors hsc_env iNTERACTIVE (get_mod_contents exports_only)
990 get_mod_contents exports_only
991 | not exports_only -- We want the whole top-level type env
992 -- so it had better be a home module
994 ; case lookupModuleEnvByName hpt mod of
995 Just mod_info -> return (map toIfaceDecl $
998 md_types (hm_details mod_info))
999 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
1000 -- This is a system error; the module should be in the HPT
1003 | otherwise -- Want the exports only
1004 = do { iface <- load_iface mod
1005 ; avails <- exportsToAvails (mi_exports iface)
1006 ; mappM get_decl avails
1010 = do { thing <- tcLookupGlobal (availName avail)
1011 ; return (filter_decl (availOccs avail) (toIfaceDecl thing)) }
1013 ---------------------
1014 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
1015 = decl { ifSigs = filter (keep_sig occs) sigs }
1016 filter_decl occs decl@(IfaceData {ifCons = IfDataTyCon th cons})
1017 = decl { ifCons = IfDataTyCon th (filter (keep_con occs) cons) }
1018 filter_decl occs decl@(IfaceData {ifCons = IfNewTyCon con})
1019 | keep_con occs con = decl
1020 | otherwise = decl {ifCons = IfAbstractTyCon} -- Hmm?
1021 filter_decl occs decl
1024 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
1025 keep_con occs con = ifConOcc con `elem` occs
1027 availOccs avail = map nameOccName (availNames avail)
1029 wantToSee (AnId id) = not (isImplicitId id)
1030 wantToSee (ADataCon _) = False -- They'll come via their TyCon
1033 ---------------------
1034 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
1036 doc = ptext SLIT("context for compiling statements")
1038 ---------------------
1039 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1040 <+> quotes (ppr mod)
1044 tcRnGetInfo :: HscEnv
1045 -> InteractiveContext
1047 -> IO (Maybe [(IfaceDecl,
1049 [(IfaceInst, SrcLoc)])])
1050 -- Used to implemnent :info in GHCi
1052 -- Look up a RdrName and return all the TyThings it might be
1053 -- A capitalised RdrName is given to us in the DataName namespace,
1054 -- but we want to treat it as *both* a data constructor
1055 -- *and* as a type or class constructor;
1056 -- hence the call to dataTcOccs, and we return up to two results
1057 tcRnGetInfo hsc_env ictxt rdr_name
1058 = initTcPrintErrors hsc_env iNTERACTIVE $
1059 setInteractiveContext ictxt $ do {
1061 -- If the identifier is a constructor (begins with an
1062 -- upper-case letter), then we need to consider both
1063 -- constructor and type class identifiers.
1064 let { rdr_names = dataTcOccs rdr_name } ;
1066 -- results :: [(Messages, Maybe Name)]
1067 results <- mapM (tryTc . lookupOccRn) rdr_names ;
1069 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1070 -- The successful lookups will be (Just name)
1071 let { (warns_s, good_names) = unzip [ (msgs, name)
1072 | (msgs, Just name) <- results] ;
1073 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1075 -- Fail if nothing good happened, else add warnings
1076 if null good_names then
1077 -- No lookup succeeded, so
1078 -- pick the first error message and report it
1079 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1080 -- while the other is "X is not in scope",
1081 -- we definitely want the former; but we might pick the latter
1082 do { addMessages (head errs_s) ; failM }
1083 else -- Add deprecation warnings
1084 mapM_ addMessages warns_s ;
1086 -- And lookup up the entities, avoiding duplicates, which arise
1087 -- because constructors and record selectors are represented by
1088 -- their parent declaration
1089 let { do_one name = do { thing <- tcLookupGlobal name
1090 ; let decl = toIfaceDecl thing
1091 ; fixity <- lookupFixityRn name
1092 ; insts <- lookupInsts thing
1093 ; return (decl, fixity, getSrcLoc thing,
1094 map mk_inst insts) } ;
1095 -- For the SrcLoc, the 'thing' has better info than
1096 -- the 'name' because getting the former forced the
1097 -- declaration to be loaded into the cache
1098 mk_inst dfun = (dfunToIfaceInst dfun, getSrcLoc dfun) ;
1099 cmp (d1,_,_,_) (d2,_,_,_) = ifName d1 `compare` ifName d2 } ;
1100 results <- mapM do_one good_names ;
1101 return (fst (removeDups cmp results))
1104 lookupInsts :: TyThing -> TcM [DFunId]
1105 lookupInsts (AClass cls)
1106 = do { loadImportedInsts cls [] -- [] means load all instances for cls
1107 ; inst_envs <- tcGetInstEnvs
1108 ; return [df | (_,_,df) <- classInstances inst_envs cls] }
1110 lookupInsts (ATyCon tc)
1111 = do { eps <- getEps -- Load all instances for all classes that are
1112 -- in the type environment (which are all the ones
1113 -- we've seen in any interface file so far
1114 ; mapM_ (\c -> loadImportedInsts c [])
1115 (typeEnvClasses (eps_PTE eps))
1116 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1117 ; return (get home_ie ++ get pkg_ie) }
1119 get ie = [df | (_,_,df) <- instEnvElts ie, relevant df]
1120 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1121 tc_name = tyConName tc
1123 lookupInsts other = return []
1126 toIfaceDecl :: TyThing -> IfaceDecl
1128 = tyThingToIfaceDecl True -- Discard IdInfo
1129 emptyNameSet -- Show data cons
1130 ext_nm (munge thing)
1132 ext_nm n = ExtPkg (nameModuleName n) (nameOccName n)
1134 -- munge transforms a thing to it's "parent" thing
1135 munge (ADataCon dc) = ATyCon (dataConTyCon dc)
1136 munge (AnId id) = case globalIdDetails id of
1137 RecordSelId tc lbl -> ATyCon tc
1138 ClassOpId cls -> AClass cls
1140 munge other_thing = other_thing
1145 %************************************************************************
1149 %************************************************************************
1152 rnDump :: SDoc -> TcRn ()
1153 -- Dump, with a banner, if -ddump-rn
1154 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1156 tcDump :: TcGblEnv -> TcRn ()
1158 = do { dflags <- getDOpts ;
1160 -- Dump short output if -ddump-types or -ddump-tc
1161 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1162 (dumpTcRn short_dump) ;
1164 -- Dump bindings if -ddump-tc
1165 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1168 short_dump = pprTcGblEnv env
1169 full_dump = pprLHsBinds (tcg_binds env)
1170 -- NB: foreign x-d's have undefined's in their types;
1171 -- hence can't show the tc_fords
1174 = do { dflags <- getDOpts ;
1175 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1176 (dumpTcRn (pprModGuts mod_guts)) ;
1178 -- Dump bindings if -ddump-tc
1179 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1181 full_dump = pprCoreBindings (mg_binds mod_guts)
1183 -- It's unpleasant having both pprModGuts and pprModDetails here
1184 pprTcGblEnv :: TcGblEnv -> SDoc
1185 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1186 tcg_insts = dfun_ids,
1188 tcg_imports = imports })
1189 = vcat [ ppr_types dfun_ids type_env
1190 , ppr_insts dfun_ids
1191 , vcat (map ppr rules)
1192 , ppr_gen_tycons (typeEnvTyCons type_env)
1193 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1194 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1196 pprModGuts :: ModGuts -> SDoc
1197 pprModGuts (ModGuts { mg_types = type_env,
1199 = vcat [ ppr_types [] type_env,
1203 ppr_types :: [Var] -> TypeEnv -> SDoc
1204 ppr_types dfun_ids type_env
1205 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1207 ids = [id | id <- typeEnvIds type_env, want_sig id]
1208 want_sig id | opt_PprStyle_Debug = True
1209 | otherwise = isLocalId id &&
1210 isExternalName (idName id) &&
1211 not (id `elem` dfun_ids)
1212 -- isLocalId ignores data constructors, records selectors etc.
1213 -- The isExternalName ignores local dictionary and method bindings
1214 -- that the type checker has invented. Top-level user-defined things
1215 -- have External names.
1217 ppr_insts :: [Var] -> SDoc
1218 ppr_insts [] = empty
1219 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1221 ppr_sigs :: [Var] -> SDoc
1223 -- Print type signatures; sort by OccName
1224 = vcat (map ppr_sig (sortLe le_sig ids))
1226 le_sig id1 id2 = getOccName id1 <= getOccName id2
1227 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1229 ppr_rules :: [IdCoreRule] -> SDoc
1230 ppr_rules [] = empty
1231 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1232 nest 4 (pprIdRules rs),
1235 ppr_gen_tycons [] = empty
1236 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1237 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]