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 )
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 checkHiBootIface env boot_names
428 = mapM_ (check_one env) boot_names
431 check_one local_env name
434 -- Look up the hi-boot one;
435 -- it should jolly well be there (else GHC bug)
436 ; case lookupTypeEnv (eps_PTE eps) name of {
437 Nothing -> pprPanic "checkHiBootIface" (ppr name) ;
440 -- Look it up in the local type env
441 -- It should be there, but it's a programmer error if not
442 case lookupTypeEnv local_env name of
443 Nothing -> addErrTc (missingBootThing boot_thing)
444 Just real_thing -> check_thing boot_thing real_thing
448 check_thing (ATyCon boot_tc) (ATyCon real_tc)
449 | isSynTyCon boot_tc && isSynTyCon real_tc,
450 defn1 `tcEqType` substTyWith tvs2 (mkTyVarTys tvs1) defn2
453 | tyConKind boot_tc == tyConKind real_tc
456 (tvs1, defn1) = getSynTyConDefn boot_tc
457 (tvs2, defn2) = getSynTyConDefn boot_tc
459 check_thing (AnId boot_id) (AnId real_id)
460 | idType boot_id `tcEqType` idType real_id
463 check_thing (ADataCon dc1) (ADataCon dc2)
464 | idType (dataConWrapId dc1) `tcEqType` idType (dataConWrapId dc2)
467 -- Can't declare a class in a hi-boot file
469 check_thing boot_thing real_thing -- Default case; failure
470 = addErrAt (srcLocSpan (getSrcLoc real_thing))
471 (bootMisMatch real_thing)
474 missingBootThing thing
475 = ppr thing <+> ptext SLIT("is defined in the hi-boot file, but not in the module")
477 = ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hi-boot file")
481 %************************************************************************
483 Type-checking the top level of a module
485 %************************************************************************
487 tcRnGroup takes a bunch of top-level source-code declarations, and
489 * gets supporting declarations from interface files
492 * and augments the TcGblEnv with the results
494 In Template Haskell it may be called repeatedly for each group of
495 declarations. It expects there to be an incoming TcGblEnv in the
496 monad; it augments it and returns the new TcGblEnv.
499 tcRnGroup :: [Name] -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
500 -- Returns the variables free in the decls, for unused-binding reporting
501 tcRnGroup boot_names decls
502 = do { -- Rename the declarations
503 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
504 setGblEnv tcg_env $ do {
506 -- Typecheck the declarations
507 tcTopSrcDecls boot_names rn_decls
510 ------------------------------------------------
511 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
513 = do { -- Bring top level binders into scope
514 (rdr_env, imports) <- importsFromLocalDecls group ;
515 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
516 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
519 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
520 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
522 -- Rename the source decls
523 (tcg_env, rn_decls) <- rnSrcDecls group ;
526 -- Dump trace of renaming part
527 rnDump (ppr rn_decls) ;
529 return (tcg_env, rn_decls)
532 ------------------------------------------------
533 tcTopSrcDecls :: [Name] -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
534 tcTopSrcDecls boot_names
535 (HsGroup { hs_tyclds = tycl_decls,
536 hs_instds = inst_decls,
537 hs_fords = foreign_decls,
538 hs_defds = default_decls,
539 hs_ruleds = rule_decls,
540 hs_valds = val_binds })
541 = do { -- Type-check the type and class decls, and all imported decls
542 -- The latter come in via tycl_decls
543 traceTc (text "Tc2") ;
545 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_names tycl_decls) ;
546 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
547 -- an error we'd better stop now, to avoid a cascade
549 -- Make these type and class decls available to stuff slurped from interface files
550 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
553 setGblEnv tcg_env $ do {
554 -- Source-language instances, including derivings,
555 -- and import the supporting declarations
556 traceTc (text "Tc3") ;
557 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
558 setGblEnv tcg_env $ do {
560 -- Foreign import declarations next. No zonking necessary
561 -- here; we can tuck them straight into the global environment.
562 traceTc (text "Tc4") ;
563 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
564 tcExtendGlobalValEnv fi_ids $ do {
566 -- Default declarations
567 traceTc (text "Tc4a") ;
568 default_tys <- tcDefaults default_decls ;
569 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
571 -- Value declarations next
572 -- We also typecheck any extra binds that came out
573 -- of the "deriving" process (deriv_binds)
574 traceTc (text "Tc5") ;
575 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
576 setLclTypeEnv lcl_env $ do {
578 -- Second pass over class and instance declarations,
579 traceTc (text "Tc6") ;
580 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
581 showLIE (text "after instDecls2") ;
584 -- They need to be zonked, so we return them
585 traceTc (text "Tc7") ;
586 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
589 rules <- tcRules rule_decls ;
592 traceTc (text "Tc7a") ;
593 tcg_env <- getGblEnv ;
594 let { all_binds = tc_val_binds `unionBags`
595 inst_binds `unionBags`
598 -- Extend the GblEnv with the (as yet un-zonked)
599 -- bindings, rules, foreign decls
600 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
601 tcg_rules = tcg_rules tcg_env ++ rules,
602 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
603 return (tcg_env', lcl_env)
608 %************************************************************************
612 %************************************************************************
616 = do { ghci_mode <- getGhciMode ;
617 tcg_env <- getGblEnv ;
619 mb_main_mod <- readMutVar v_MainModIs ;
620 mb_main_fn <- readMutVar v_MainFunIs ;
621 let { main_mod = case mb_main_mod of {
622 Just mod -> mkModuleName mod ;
623 Nothing -> mAIN_Name } ;
624 main_fn = case mb_main_fn of {
625 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
626 Nothing -> main_RDR_Unqual } } ;
628 check_main ghci_mode tcg_env main_mod main_fn
632 check_main ghci_mode tcg_env main_mod main_fn
633 -- If we are in module Main, check that 'main' is defined.
634 -- It may be imported from another module!
636 -- ToDo: We have to return the main_name separately, because it's a
637 -- bona fide 'use', and should be recorded as such, but the others
640 -- Blimey: a whole page of code to do this...
641 | mod_name /= main_mod
645 = addErrCtxt mainCtxt $
646 do { mb_main <- lookupSrcOcc_maybe main_fn
647 -- Check that 'main' is in scope
648 -- It might be imported from another module!
650 Nothing -> do { complain_no_main
653 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
654 -- :Main.main :: IO () = runIO main
656 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
659 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
660 main_bind = noLoc (VarBind root_main_id main_expr) }
662 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
664 tcg_dus = tcg_dus tcg_env
665 `plusDU` usesOnly (unitFV main_name)
669 mod_name = moduleName (tcg_mod tcg_env)
671 complain_no_main | ghci_mode == Interactive = return ()
672 | otherwise = failWithTc noMainMsg
673 -- In interactive mode, don't worry about the absence of 'main'
674 -- In other modes, fail altogether, so that we don't go on
675 -- and complain a second time when processing the export list.
677 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
678 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
679 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
683 %*********************************************************
687 %*********************************************************
691 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
692 setInteractiveContext icxt thing_inside
693 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
694 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
695 tcg_type_env = ic_type_env icxt}) $
696 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
703 -> InteractiveContext
705 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
706 -- The returned [Name] is the same as the input except for
707 -- ExprStmt, in which case the returned [Name] is [itName]
709 -- The returned TypecheckedHsExpr is of type IO [ () ],
710 -- a list of the bound values, coerced to ().
712 tcRnStmt hsc_env ictxt rdr_stmt
713 = initTcPrintErrors hsc_env iNTERACTIVE $
714 setInteractiveContext ictxt $ do {
716 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
717 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
718 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
721 -- The real work is done here
722 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
724 traceTc (text "tcs 1") ;
725 let { -- Make all the bound ids "global" ids, now that
726 -- they're notionally top-level bindings. This is
727 -- important: otherwise when we come to compile an expression
728 -- using these ids later, the byte code generator will consider
729 -- the occurrences to be free rather than global.
730 global_ids = map (globaliseId VanillaGlobal) bound_ids ;
732 -- Update the interactive context
733 rn_env = ic_rn_local_env ictxt ;
734 type_env = ic_type_env ictxt ;
736 bound_names = map idName global_ids ;
737 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
739 -- Remove any shadowed bindings from the type_env;
740 -- they are inaccessible but might, I suppose, cause
741 -- a space leak if we leave them there
742 shadowed = [ n | name <- bound_names,
743 let rdr_name = mkRdrUnqual (nameOccName name),
744 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
746 filtered_type_env = delListFromNameEnv type_env shadowed ;
747 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
749 new_ic = ictxt { ic_rn_local_env = new_rn_env,
750 ic_type_env = new_type_env }
753 dumpOptTcRn Opt_D_dump_tc
754 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
755 text "Typechecked expr" <+> ppr tc_expr]) ;
757 returnM (new_ic, bound_names, tc_expr)
762 Here is the grand plan, implemented in tcUserStmt
764 What you type The IO [HValue] that hscStmt returns
765 ------------- ------------------------------------
766 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
769 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
772 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
773 [NB: result not printed] bindings: [it]
775 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
776 result showable) bindings: [it]
778 expr (of non-IO type,
779 result not showable) ==> error
783 ---------------------------
784 tcUserStmt :: LStmt Name -> TcM ([Id], LHsExpr Id)
785 tcUserStmt (L _ (ExprStmt expr _))
786 = newUnique `thenM` \ uniq ->
788 fresh_it = itName uniq
789 the_bind = noLoc $ FunBind (noLoc fresh_it) False
790 (mkMatchGroup [mkSimpleMatch [] expr])
792 tryTcLIE_ (do { -- Try this if the other fails
793 traceTc (text "tcs 1b") ;
795 nlLetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive],
796 nlExprStmt (nlHsApp (nlHsVar printName)
799 (do { -- Try this first
800 traceTc (text "tcs 1a") ;
801 tc_stmts [nlBindStmt (nlVarPat fresh_it) expr] })
803 tcUserStmt stmt = tc_stmts [stmt]
805 ---------------------------
807 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
809 ret_ty = mkListTy unitTy ;
810 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
812 names = map unLoc (collectStmtsBinders stmts) ;
814 stmt_ctxt = SC { sc_what = DoExpr,
816 sc_body = check_body,
819 infer_rhs rhs = do { (rhs', rhs_ty) <- tcInferRho rhs
820 ; [pat_ty] <- unifyTyConApp ioTyCon rhs_ty
821 ; return (rhs', pat_ty) } ;
822 check_body body = tcCheckRho body io_ret_ty ;
824 -- mk_return builds the expression
825 -- returnIO @ [()] [coerce () x, .., coerce () z]
827 -- Despite the inconvenience of building the type applications etc,
828 -- this *has* to be done in type-annotated post-typecheck form
829 -- because we are going to return a list of *polymorphic* values
830 -- coerced to type (). If we built a *source* stmt
831 -- return [coerce x, ..., coerce z]
832 -- then the type checker would instantiate x..z, and we wouldn't
833 -- get their *polymorphic* values. (And we'd get ambiguity errs
834 -- if they were overloaded, since they aren't applied to anything.)
835 mk_return ret_id ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
836 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
837 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
840 io_ty = mkTyConApp ioTyCon []
843 -- OK, we're ready to typecheck the stmts
844 traceTc (text "tcs 2") ;
845 ((ids, tc_expr), lie) <- getLIE $ do {
846 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
848 -- Look up the names right in the middle,
849 -- where they will all be in scope
850 ids <- mappM tcLookupId names ;
851 ret_id <- tcLookupId returnIOName ; -- return @ IO
852 return (ids, [nlResultStmt (mk_return ret_id ids)]) } ;
854 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
855 return (ids, noLoc (HsDo DoExpr tc_stmts io_ids io_ret_ty))
858 -- Simplify the context right here, so that we fail
859 -- if there aren't enough instances. Notably, when we see
861 -- we use recoverTc_ to try it <- e
862 -- and then let it = e
863 -- It's the simplify step that rejects the first.
864 traceTc (text "tcs 3") ;
865 const_binds <- tcSimplifyInteractive lie ;
867 -- Build result expression and zonk it
868 let { expr = mkHsLet const_binds tc_expr } ;
869 zonked_expr <- zonkTopLExpr expr ;
870 zonked_ids <- zonkTopBndrs ids ;
872 -- None of the Ids should be of unboxed type, because we
873 -- cast them all to HValues in the end!
874 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
876 return (zonked_ids, zonked_expr)
879 combine stmt (ids, stmts) = (ids, stmt:stmts)
880 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
881 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
885 tcRnExpr just finds the type of an expression
889 -> InteractiveContext
892 tcRnExpr hsc_env ictxt rdr_expr
893 = initTcPrintErrors hsc_env iNTERACTIVE $
894 setInteractiveContext ictxt $ do {
896 (rn_expr, fvs) <- rnLExpr rdr_expr ;
899 -- Now typecheck the expression;
900 -- it might have a rank-2 type (e.g. :t runST)
901 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
902 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
903 tcSimplifyInteractive lie_top ;
905 let { all_expr_ty = mkForAllTys qtvs $
906 mkFunTys (map idType dict_ids) $
908 zonkTcType all_expr_ty
911 smpl_doc = ptext SLIT("main expression")
914 tcRnType just finds the kind of a type
918 -> InteractiveContext
921 tcRnType hsc_env ictxt rdr_type
922 = initTcPrintErrors hsc_env iNTERACTIVE $
923 setInteractiveContext ictxt $ do {
925 rn_type <- rnLHsType doc rdr_type ;
928 -- Now kind-check the type
929 (ty', kind) <- kcHsType rn_type ;
933 doc = ptext SLIT("In GHCi input")
939 %************************************************************************
941 More GHCi stuff, to do with browsing and getting info
943 %************************************************************************
947 mkExportEnv :: HscEnv -> [ModuleName] -- Expose these modules' exports only
949 mkExportEnv hsc_env exports
950 = do { mb_envs <- initTcPrintErrors hsc_env iNTERACTIVE $
951 mappM getModuleExports exports
953 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
954 Nothing -> return emptyGlobalRdrEnv
955 -- Some error; initTc will have printed it
958 getModuleExports :: ModuleName -> TcM GlobalRdrEnv
960 = do { iface <- load_iface mod
961 ; loadOrphanModules (dep_orphs (mi_deps iface))
962 -- Load any orphan-module interfaces,
963 -- so their instances are visible
964 ; avails <- exportsToAvails (mi_exports iface)
965 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
966 | avail <- avails, name <- availNames avail ] }
967 ; returnM (mkGlobalRdrEnv gres) }
969 vanillaProv :: ModuleName -> Provenance
970 -- We're building a GlobalRdrEnv as if the user imported
971 -- all the specified modules into the global interactive module
972 vanillaProv mod = Imported [ImportSpec mod mod False
973 (srcLocSpan interactiveSrcLoc)] False
979 -> InteractiveContext
980 -> ModuleName -- Module to inspect
981 -> Bool -- Grab just the exports, or the whole toplev
982 -> IO (Maybe [IfaceDecl])
984 getModuleContents hsc_env ictxt mod exports_only
985 = initTcPrintErrors hsc_env iNTERACTIVE (get_mod_contents exports_only)
987 get_mod_contents exports_only
988 | not exports_only -- We want the whole top-level type env
989 -- so it had better be a home module
991 ; case lookupModuleEnvByName hpt mod of
992 Just mod_info -> return (map toIfaceDecl $
995 md_types (hm_details mod_info))
996 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
997 -- This is a system error; the module should be in the HPT
1000 | otherwise -- Want the exports only
1001 = do { iface <- load_iface mod
1002 ; avails <- exportsToAvails (mi_exports iface)
1003 ; mappM get_decl avails
1007 = do { thing <- tcLookupGlobal (availName avail)
1008 ; return (filter_decl (availOccs avail) (toIfaceDecl thing)) }
1010 ---------------------
1011 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
1012 = decl { ifSigs = filter (keep_sig occs) sigs }
1013 filter_decl occs decl@(IfaceData {ifCons = IfDataTyCon th cons})
1014 = decl { ifCons = IfDataTyCon th (filter (keep_con occs) cons) }
1015 filter_decl occs decl@(IfaceData {ifCons = IfNewTyCon con})
1016 | keep_con occs con = decl
1017 | otherwise = decl {ifCons = IfAbstractTyCon} -- Hmm?
1018 filter_decl occs decl
1021 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
1022 keep_con occs con = ifConOcc con `elem` occs
1024 availOccs avail = map nameOccName (availNames avail)
1026 wantToSee (AnId id) = not (isImplicitId id)
1027 wantToSee (ADataCon _) = False -- They'll come via their TyCon
1030 ---------------------
1031 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
1033 doc = ptext SLIT("context for compiling statements")
1035 ---------------------
1036 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1037 <+> quotes (ppr mod)
1041 tcRnGetInfo :: HscEnv
1042 -> InteractiveContext
1044 -> IO (Maybe [(IfaceDecl,
1046 [(IfaceInst, SrcLoc)])])
1047 -- Used to implemnent :info in GHCi
1049 -- Look up a RdrName and return all the TyThings it might be
1050 -- A capitalised RdrName is given to us in the DataName namespace,
1051 -- but we want to treat it as *both* a data constructor
1052 -- *and* as a type or class constructor;
1053 -- hence the call to dataTcOccs, and we return up to two results
1054 tcRnGetInfo hsc_env ictxt rdr_name
1055 = initTcPrintErrors hsc_env iNTERACTIVE $
1056 setInteractiveContext ictxt $ do {
1058 -- If the identifier is a constructor (begins with an
1059 -- upper-case letter), then we need to consider both
1060 -- constructor and type class identifiers.
1061 let { rdr_names = dataTcOccs rdr_name } ;
1063 -- results :: [(Messages, Maybe Name)]
1064 results <- mapM (tryTc . lookupOccRn) rdr_names ;
1066 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1067 -- The successful lookups will be (Just name)
1068 let { (warns_s, good_names) = unzip [ (msgs, name)
1069 | (msgs, Just name) <- results] ;
1070 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1072 -- Fail if nothing good happened, else add warnings
1073 if null good_names then
1074 -- No lookup succeeded, so
1075 -- pick the first error message and report it
1076 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1077 -- while the other is "X is not in scope",
1078 -- we definitely want the former; but we might pick the latter
1079 do { addMessages (head errs_s) ; failM }
1080 else -- Add deprecation warnings
1081 mapM_ addMessages warns_s ;
1083 -- And lookup up the entities, avoiding duplicates, which arise
1084 -- because constructors and record selectors are represented by
1085 -- their parent declaration
1086 let { do_one name = do { thing <- tcLookupGlobal name
1087 ; let decl = toIfaceDecl thing
1088 ; fixity <- lookupFixityRn name
1089 ; insts <- lookupInsts thing
1090 ; return (decl, fixity, getSrcLoc thing,
1091 map mk_inst insts) } ;
1092 -- For the SrcLoc, the 'thing' has better info than
1093 -- the 'name' because getting the former forced the
1094 -- declaration to be loaded into the cache
1095 mk_inst dfun = (dfunToIfaceInst dfun, getSrcLoc dfun) ;
1096 cmp (d1,_,_,_) (d2,_,_,_) = ifName d1 `compare` ifName d2 } ;
1097 results <- mapM do_one good_names ;
1098 return (fst (removeDups cmp results))
1101 lookupInsts :: TyThing -> TcM [DFunId]
1102 lookupInsts (AClass cls)
1103 = do { loadImportedInsts cls [] -- [] means load all instances for cls
1104 ; inst_envs <- tcGetInstEnvs
1105 ; return [df | (_,_,df) <- classInstances inst_envs cls] }
1107 lookupInsts (ATyCon tc)
1108 = do { eps <- getEps -- Load all instances for all classes that are
1109 -- in the type environment (which are all the ones
1110 -- we've seen in any interface file so far
1111 ; mapM_ (\c -> loadImportedInsts c [])
1112 (typeEnvClasses (eps_PTE eps))
1113 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1114 ; return (get home_ie ++ get pkg_ie) }
1116 get ie = [df | (_,_,df) <- instEnvElts ie, relevant df]
1117 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1118 tc_name = tyConName tc
1120 lookupInsts other = return []
1123 toIfaceDecl :: TyThing -> IfaceDecl
1125 = tyThingToIfaceDecl True -- Discard IdInfo
1126 emptyNameSet -- Show data cons
1127 ext_nm (munge thing)
1129 ext_nm n = ExtPkg (nameModuleName n) (nameOccName n)
1131 -- munge transforms a thing to it's "parent" thing
1132 munge (ADataCon dc) = ATyCon (dataConTyCon dc)
1133 munge (AnId id) = case globalIdDetails id of
1134 RecordSelId tc lbl -> ATyCon tc
1135 ClassOpId cls -> AClass cls
1137 munge other_thing = other_thing
1142 %************************************************************************
1146 %************************************************************************
1149 rnDump :: SDoc -> TcRn ()
1150 -- Dump, with a banner, if -ddump-rn
1151 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1153 tcDump :: TcGblEnv -> TcRn ()
1155 = do { dflags <- getDOpts ;
1157 -- Dump short output if -ddump-types or -ddump-tc
1158 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1159 (dumpTcRn short_dump) ;
1161 -- Dump bindings if -ddump-tc
1162 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1165 short_dump = pprTcGblEnv env
1166 full_dump = pprLHsBinds (tcg_binds env)
1167 -- NB: foreign x-d's have undefined's in their types;
1168 -- hence can't show the tc_fords
1171 = do { dflags <- getDOpts ;
1172 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1173 (dumpTcRn (pprModGuts mod_guts)) ;
1175 -- Dump bindings if -ddump-tc
1176 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1178 full_dump = pprCoreBindings (mg_binds mod_guts)
1180 -- It's unpleasant having both pprModGuts and pprModDetails here
1181 pprTcGblEnv :: TcGblEnv -> SDoc
1182 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1183 tcg_insts = dfun_ids,
1185 tcg_imports = imports })
1186 = vcat [ ppr_types dfun_ids type_env
1187 , ppr_insts dfun_ids
1188 , vcat (map ppr rules)
1189 , ppr_gen_tycons (typeEnvTyCons type_env)
1190 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1191 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1193 pprModGuts :: ModGuts -> SDoc
1194 pprModGuts (ModGuts { mg_types = type_env,
1196 = vcat [ ppr_types [] type_env,
1200 ppr_types :: [Var] -> TypeEnv -> SDoc
1201 ppr_types dfun_ids type_env
1202 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1204 ids = [id | id <- typeEnvIds type_env, want_sig id]
1205 want_sig id | opt_PprStyle_Debug = True
1206 | otherwise = isLocalId id &&
1207 isExternalName (idName id) &&
1208 not (id `elem` dfun_ids)
1209 -- isLocalId ignores data constructors, records selectors etc.
1210 -- The isExternalName ignores local dictionary and method bindings
1211 -- that the type checker has invented. Top-level user-defined things
1212 -- have External names.
1214 ppr_insts :: [Var] -> SDoc
1215 ppr_insts [] = empty
1216 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1218 ppr_sigs :: [Var] -> SDoc
1220 -- Print type signatures; sort by OccName
1221 = vcat (map ppr_sig (sortLe le_sig ids))
1223 le_sig id1 id2 = getOccName id1 <= getOccName id2
1224 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1226 ppr_rules :: [IdCoreRule] -> SDoc
1227 ppr_rules [] = empty
1228 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1229 nest 4 (pprIdRules rs),
1232 ppr_gen_tycons [] = empty
1233 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1234 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]