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 -- In one-shot mode, record boot-file info in the EPS
165 ifM (isOneShot (hsc_mode hsc_env)) $
166 updateEps_ (\eps -> eps { eps_is_boot = imp_dep_mods imports }) ;
168 -- Update the gbl env
169 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
170 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
172 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
173 -- Fail if there are any errors so far
174 -- The error printing (if needed) takes advantage
175 -- of the tcg_env we have now set
178 -- Load any orphan-module interfaces, so that
179 -- their rules and instance decls will be found
180 loadOrphanModules (imp_orphs imports) ;
182 traceRn (text "rn1a") ;
183 -- Rename and type check the declarations
184 tcg_env <- tcRnSrcDecls local_decls ;
185 setGblEnv tcg_env $ do {
187 traceRn (text "rn3") ;
189 -- Report the use of any deprecated things
190 -- We do this before processsing the export list so
191 -- that we don't bleat about re-exporting a deprecated
192 -- thing (especially via 'module Foo' export item)
193 -- Only uses in the body of the module are complained about
194 reportDeprecations tcg_env ;
196 -- Process the export list
197 exports <- exportsFromAvail (isJust maybe_mod) exports ;
199 {- Jan 04: I don't think this is necessary any more; usage info is derived from tcg_dus
200 -- Get any supporting decls for the exports that have not already
201 -- been sucked in for the declarations in the body of the module.
202 -- (This can happen if something is imported only to be re-exported.)
204 -- Importing these supporting declarations is required
205 -- *only* to gether usage information
206 -- (see comments with MkIface.mkImportInfo for why)
207 -- We don't need the results, but sucking them in may side-effect
208 -- the ExternalPackageState, apart from recording usage
209 mappM (tcLookupGlobal . availName) export_avails ;
212 -- Check whether the entire module is deprecated
213 -- This happens only once per module
214 let { mod_deprecs = checkModDeprec mod_deprec } ;
216 -- Add exports and deprecations to envt
217 let { final_env = tcg_env { tcg_exports = exports,
218 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
219 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
221 -- A module deprecation over-rides the earlier ones
224 -- Report unused names
225 reportUnusedNames final_env ;
227 -- Dump output and return
234 %************************************************************************
236 Type-checking external-core modules
238 %************************************************************************
241 tcRnExtCore :: HscEnv
243 -> IO (Messages, Maybe ModGuts)
244 -- Nothing => some error occurred
246 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
247 -- The decls are IfaceDecls; all names are original names
248 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
250 initTc hsc_env this_mod $ do {
252 let { ldecls = map noLoc decls } ;
254 -- Deal with the type declarations; first bring their stuff
255 -- into scope, then rname them, then type check them
256 (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup ldecls) ;
258 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
259 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
262 rn_decls <- rnTyClDecls ldecls ;
265 -- Dump trace of renaming part
266 rnDump (ppr rn_decls) ;
268 -- Typecheck them all together so that
269 -- any mutually recursive types are done right
270 tcg_env <- checkNoErrs (tcTyAndClassDecls [{- no boot names -}] rn_decls) ;
271 -- Make the new type env available to stuff slurped from interface files
273 setGblEnv tcg_env $ do {
275 -- Now the core bindings
276 core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;
280 bndrs = bindersOfBinds core_binds ;
281 my_exports = mkNameSet (map idName bndrs) ;
282 -- ToDo: export the data types also?
284 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
286 mod_guts = ModGuts { mg_module = this_mod,
287 mg_usages = [], -- ToDo: compute usage
288 mg_dir_imps = [], -- ??
289 mg_deps = noDependencies, -- ??
290 mg_exports = my_exports,
291 mg_types = final_type_env,
292 mg_insts = tcg_insts tcg_env,
294 mg_binds = core_binds,
297 mg_rdr_env = emptyGlobalRdrEnv,
298 mg_fix_env = emptyFixityEnv,
299 mg_deprecs = NoDeprecs,
303 tcCoreDump mod_guts ;
308 mkFakeGroup decls -- Rather clumsy; lots of unused fields
309 = HsGroup { hs_tyclds = decls, -- This is the one we want
310 hs_valds = [], hs_fords = [],
311 hs_instds = [], hs_fixds = [], hs_depds = [],
312 hs_ruleds = [], hs_defds = [] }
316 %************************************************************************
318 Type-checking the top level of a module
320 %************************************************************************
323 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
324 -- Returns the variables free in the decls
325 -- Reason: solely to report unused imports and bindings
327 = do { boot_names <- loadHiBootInterface ;
329 -- Do all the declarations
330 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_names decls) ;
332 -- tcSimplifyTop deals with constant or ambiguous InstIds.
333 -- How could there be ambiguous ones? They can only arise if a
334 -- top-level decl falls under the monomorphism
335 -- restriction, and no subsequent decl instantiates its
336 -- type. (Usually, ambiguous type variables are resolved
337 -- during the generalisation step.)
338 traceTc (text "Tc8") ;
339 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
340 -- Setting the global env exposes the instances to tcSimplifyTop
341 -- Setting the local env exposes the local Ids to tcSimplifyTop,
342 -- so that we get better error messages (monomorphism restriction)
344 -- Backsubstitution. This must be done last.
345 -- Even tcSimplifyTop may do some unification.
346 traceTc (text "Tc9") ;
347 let { (tcg_env, _) = tc_envs ;
348 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
349 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
351 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
354 let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
356 -- Compre the hi-boot iface (if any) with the real thing
357 checkHiBootIface final_type_env boot_names ;
359 -- Make the new type env available to stuff slurped from interface files
360 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
362 return (tcg_env { tcg_type_env = final_type_env,
363 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' })
366 tc_rn_src_decls :: [Name] -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
367 -- Loops around dealing with each top level inter-splice group
368 -- in turn, until it's dealt with the entire module
369 tc_rn_src_decls boot_names ds
370 = do { let { (first_group, group_tail) = findSplice ds } ;
371 -- If ds is [] we get ([], Nothing)
373 -- Type check the decls up to, but not including, the first splice
374 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_names first_group ;
376 -- Bale out if errors; for example, error recovery when checking
377 -- the RHS of 'main' can mean that 'main' is not in the envt for
378 -- the subsequent checkMain test
383 -- If there is no splice, we're nearly done
385 Nothing -> do { -- Last thing: check for `main'
386 tcg_env <- checkMain ;
387 return (tcg_env, tcl_env)
390 -- If there's a splice, we must carry on
391 Just (SpliceDecl splice_expr, rest_ds) -> do {
393 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
396 -- Rename the splice expression, and get its supporting decls
397 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
398 failIfErrsM ; -- Don't typecheck if renaming failed
400 -- Execute the splice
401 spliced_decls <- tcSpliceDecls rn_splice_expr ;
403 -- Glue them on the front of the remaining decls and loop
404 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
405 tc_rn_src_decls boot_names (spliced_decls ++ rest_ds)
410 %************************************************************************
412 Comparing the hi-boot interface with the real thing
414 %************************************************************************
416 In both one-shot mode and GHCi mode, hi-boot interfaces are demand-loaded
417 into the External Package Table. Once we've typechecked the body of the
418 module, we want to compare what we've found (gathered in a TypeEnv) with
419 the hi-boot stuff in the EPT. We do so here, using the export list of
420 the hi-boot interface as our checklist.
423 checkHiBootIface :: TypeEnv -> [Name] -> TcM ()
424 -- Compare the hi-boot file for this module (if there is one)
425 -- with the type environment we've just come up with
426 checkHiBootIface env boot_names
427 = mapM_ (check_one env) boot_names
430 check_one local_env name
433 -- Look up the hi-boot one;
434 -- it should jolly well be there (else GHC bug)
435 ; case lookupTypeEnv (eps_PTE eps) name of {
436 Nothing -> pprPanic "checkHiBootIface" (ppr name) ;
439 -- Look it up in the local type env
440 -- It should be there, but it's a programmer error if not
441 case lookupTypeEnv local_env name of
442 Nothing -> addErrTc (missingBootThing boot_thing)
443 Just real_thing -> check_thing boot_thing real_thing
447 check_thing (ATyCon boot_tc) (ATyCon real_tc)
448 | isSynTyCon boot_tc && isSynTyCon real_tc,
449 defn1 `tcEqType` substTyWith tvs2 (mkTyVarTys tvs1) defn2
452 | tyConKind boot_tc == tyConKind real_tc
455 (tvs1, defn1) = getSynTyConDefn boot_tc
456 (tvs2, defn2) = getSynTyConDefn boot_tc
458 check_thing (AnId boot_id) (AnId real_id)
459 | idType boot_id `tcEqType` idType real_id
462 check_thing (ADataCon dc1) (ADataCon dc2)
463 | idType (dataConWrapId dc1) `tcEqType` idType (dataConWrapId dc2)
466 -- Can't declare a class in a hi-boot file
468 check_thing boot_thing real_thing -- Default case; failure
469 = addErrAt (srcLocSpan (getSrcLoc real_thing))
470 (bootMisMatch real_thing)
473 missingBootThing thing
474 = ppr thing <+> ptext SLIT("is defined in the hi-boot file, but not in the module")
476 = ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hi-boot file")
480 %************************************************************************
482 Type-checking the top level of a module
484 %************************************************************************
486 tcRnGroup takes a bunch of top-level source-code declarations, and
488 * gets supporting declarations from interface files
491 * and augments the TcGblEnv with the results
493 In Template Haskell it may be called repeatedly for each group of
494 declarations. It expects there to be an incoming TcGblEnv in the
495 monad; it augments it and returns the new TcGblEnv.
498 tcRnGroup :: [Name] -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
499 -- Returns the variables free in the decls, for unused-binding reporting
500 tcRnGroup boot_names decls
501 = do { -- Rename the declarations
502 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
503 setGblEnv tcg_env $ do {
505 -- Typecheck the declarations
506 tcTopSrcDecls boot_names rn_decls
509 ------------------------------------------------
510 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
512 = do { -- Bring top level binders into scope
513 (rdr_env, imports) <- importsFromLocalDecls group ;
514 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
515 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
518 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
519 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
521 -- Rename the source decls
522 (tcg_env, rn_decls) <- rnSrcDecls group ;
525 -- Dump trace of renaming part
526 rnDump (ppr rn_decls) ;
528 return (tcg_env, rn_decls)
531 ------------------------------------------------
532 tcTopSrcDecls :: [Name] -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
533 tcTopSrcDecls boot_names
534 (HsGroup { hs_tyclds = tycl_decls,
535 hs_instds = inst_decls,
536 hs_fords = foreign_decls,
537 hs_defds = default_decls,
538 hs_ruleds = rule_decls,
539 hs_valds = val_binds })
540 = do { -- Type-check the type and class decls, and all imported decls
541 -- The latter come in via tycl_decls
542 traceTc (text "Tc2") ;
544 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_names tycl_decls) ;
545 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
546 -- an error we'd better stop now, to avoid a cascade
548 -- Make these type and class decls available to stuff slurped from interface files
549 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
552 setGblEnv tcg_env $ do {
553 -- Source-language instances, including derivings,
554 -- and import the supporting declarations
555 traceTc (text "Tc3") ;
556 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
557 setGblEnv tcg_env $ do {
559 -- Foreign import declarations next. No zonking necessary
560 -- here; we can tuck them straight into the global environment.
561 traceTc (text "Tc4") ;
562 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
563 tcExtendGlobalValEnv fi_ids $ do {
565 -- Default declarations
566 traceTc (text "Tc4a") ;
567 default_tys <- tcDefaults default_decls ;
568 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
570 -- Value declarations next
571 -- We also typecheck any extra binds that came out
572 -- of the "deriving" process (deriv_binds)
573 traceTc (text "Tc5") ;
574 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
575 setLclTypeEnv lcl_env $ do {
577 -- Second pass over class and instance declarations,
578 traceTc (text "Tc6") ;
579 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
580 showLIE (text "after instDecls2") ;
583 -- They need to be zonked, so we return them
584 traceTc (text "Tc7") ;
585 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
588 rules <- tcRules rule_decls ;
591 traceTc (text "Tc7a") ;
592 tcg_env <- getGblEnv ;
593 let { all_binds = tc_val_binds `unionBags`
594 inst_binds `unionBags`
597 -- Extend the GblEnv with the (as yet un-zonked)
598 -- bindings, rules, foreign decls
599 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
600 tcg_rules = tcg_rules tcg_env ++ rules,
601 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
602 return (tcg_env', lcl_env)
607 %************************************************************************
611 %************************************************************************
615 = do { ghci_mode <- getGhciMode ;
616 tcg_env <- getGblEnv ;
618 mb_main_mod <- readMutVar v_MainModIs ;
619 mb_main_fn <- readMutVar v_MainFunIs ;
620 let { main_mod = case mb_main_mod of {
621 Just mod -> mkModuleName mod ;
622 Nothing -> mAIN_Name } ;
623 main_fn = case mb_main_fn of {
624 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
625 Nothing -> main_RDR_Unqual } } ;
627 check_main ghci_mode tcg_env main_mod main_fn
631 check_main ghci_mode tcg_env main_mod main_fn
632 -- If we are in module Main, check that 'main' is defined.
633 -- It may be imported from another module!
635 -- ToDo: We have to return the main_name separately, because it's a
636 -- bona fide 'use', and should be recorded as such, but the others
639 -- Blimey: a whole page of code to do this...
640 | mod_name /= main_mod
644 = addErrCtxt mainCtxt $
645 do { mb_main <- lookupSrcOcc_maybe main_fn
646 -- Check that 'main' is in scope
647 -- It might be imported from another module!
649 Nothing -> do { complain_no_main
652 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
653 -- :Main.main :: IO () = runIO main
655 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
658 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
659 main_bind = noLoc (VarBind root_main_id main_expr) }
661 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
663 tcg_dus = tcg_dus tcg_env
664 `plusDU` usesOnly (unitFV main_name)
668 mod_name = moduleName (tcg_mod tcg_env)
670 complain_no_main | ghci_mode == Interactive = return ()
671 | otherwise = failWithTc noMainMsg
672 -- In interactive mode, don't worry about the absence of 'main'
673 -- In other modes, fail altogether, so that we don't go on
674 -- and complain a second time when processing the export list.
676 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
677 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
678 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
682 %*********************************************************
686 %*********************************************************
690 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
691 setInteractiveContext icxt thing_inside
692 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
693 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
694 tcg_type_env = ic_type_env icxt}) $
695 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
702 -> InteractiveContext
704 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
705 -- The returned [Name] is the same as the input except for
706 -- ExprStmt, in which case the returned [Name] is [itName]
708 -- The returned TypecheckedHsExpr is of type IO [ () ],
709 -- a list of the bound values, coerced to ().
711 tcRnStmt hsc_env ictxt rdr_stmt
712 = initTcPrintErrors hsc_env iNTERACTIVE $
713 setInteractiveContext ictxt $ do {
715 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
716 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
717 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
720 -- The real work is done here
721 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
723 traceTc (text "tcs 1") ;
724 let { -- Make all the bound ids "global" ids, now that
725 -- they're notionally top-level bindings. This is
726 -- important: otherwise when we come to compile an expression
727 -- using these ids later, the byte code generator will consider
728 -- the occurrences to be free rather than global.
729 global_ids = map (globaliseId VanillaGlobal) bound_ids ;
731 -- Update the interactive context
732 rn_env = ic_rn_local_env ictxt ;
733 type_env = ic_type_env ictxt ;
735 bound_names = map idName global_ids ;
736 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
738 -- Remove any shadowed bindings from the type_env;
739 -- they are inaccessible but might, I suppose, cause
740 -- a space leak if we leave them there
741 shadowed = [ n | name <- bound_names,
742 let rdr_name = mkRdrUnqual (nameOccName name),
743 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
745 filtered_type_env = delListFromNameEnv type_env shadowed ;
746 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
748 new_ic = ictxt { ic_rn_local_env = new_rn_env,
749 ic_type_env = new_type_env }
752 dumpOptTcRn Opt_D_dump_tc
753 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
754 text "Typechecked expr" <+> ppr tc_expr]) ;
756 returnM (new_ic, bound_names, tc_expr)
761 Here is the grand plan, implemented in tcUserStmt
763 What you type The IO [HValue] that hscStmt returns
764 ------------- ------------------------------------
765 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
768 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
771 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
772 [NB: result not printed] bindings: [it]
774 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
775 result showable) bindings: [it]
777 expr (of non-IO type,
778 result not showable) ==> error
782 ---------------------------
783 tcUserStmt :: LStmt Name -> TcM ([Id], LHsExpr Id)
784 tcUserStmt (L _ (ExprStmt expr _))
785 = newUnique `thenM` \ uniq ->
787 fresh_it = itName uniq
788 the_bind = noLoc $ FunBind (noLoc fresh_it) False
789 (mkMatchGroup [mkSimpleMatch [] expr])
791 tryTcLIE_ (do { -- Try this if the other fails
792 traceTc (text "tcs 1b") ;
794 nlLetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive],
795 nlExprStmt (nlHsApp (nlHsVar printName)
798 (do { -- Try this first
799 traceTc (text "tcs 1a") ;
800 tc_stmts [nlBindStmt (nlVarPat fresh_it) expr] })
802 tcUserStmt stmt = tc_stmts [stmt]
804 ---------------------------
806 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
808 ret_ty = mkListTy unitTy ;
809 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
811 names = map unLoc (collectStmtsBinders stmts) ;
813 stmt_ctxt = SC { sc_what = DoExpr,
815 sc_body = check_body,
818 infer_rhs rhs = do { (rhs', rhs_ty) <- tcInferRho rhs
819 ; [pat_ty] <- unifyTyConApp ioTyCon rhs_ty
820 ; return (rhs', pat_ty) } ;
821 check_body body = tcCheckRho body io_ret_ty ;
823 -- mk_return builds the expression
824 -- returnIO @ [()] [coerce () x, .., coerce () z]
826 -- Despite the inconvenience of building the type applications etc,
827 -- this *has* to be done in type-annotated post-typecheck form
828 -- because we are going to return a list of *polymorphic* values
829 -- coerced to type (). If we built a *source* stmt
830 -- return [coerce x, ..., coerce z]
831 -- then the type checker would instantiate x..z, and we wouldn't
832 -- get their *polymorphic* values. (And we'd get ambiguity errs
833 -- if they were overloaded, since they aren't applied to anything.)
834 mk_return ret_id ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
835 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
836 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
839 io_ty = mkTyConApp ioTyCon []
842 -- OK, we're ready to typecheck the stmts
843 traceTc (text "tcs 2") ;
844 ((ids, tc_expr), lie) <- getLIE $ do {
845 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
847 -- Look up the names right in the middle,
848 -- where they will all be in scope
849 ids <- mappM tcLookupId names ;
850 ret_id <- tcLookupId returnIOName ; -- return @ IO
851 return (ids, [nlResultStmt (mk_return ret_id ids)]) } ;
853 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
854 return (ids, noLoc (HsDo DoExpr tc_stmts io_ids io_ret_ty))
857 -- Simplify the context right here, so that we fail
858 -- if there aren't enough instances. Notably, when we see
860 -- we use recoverTc_ to try it <- e
861 -- and then let it = e
862 -- It's the simplify step that rejects the first.
863 traceTc (text "tcs 3") ;
864 const_binds <- tcSimplifyInteractive lie ;
866 -- Build result expression and zonk it
867 let { expr = mkHsLet const_binds tc_expr } ;
868 zonked_expr <- zonkTopLExpr expr ;
869 zonked_ids <- zonkTopBndrs ids ;
871 -- None of the Ids should be of unboxed type, because we
872 -- cast them all to HValues in the end!
873 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
875 return (zonked_ids, zonked_expr)
878 combine stmt (ids, stmts) = (ids, stmt:stmts)
879 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
880 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
884 tcRnExpr just finds the type of an expression
888 -> InteractiveContext
891 tcRnExpr hsc_env ictxt rdr_expr
892 = initTcPrintErrors hsc_env iNTERACTIVE $
893 setInteractiveContext ictxt $ do {
895 (rn_expr, fvs) <- rnLExpr rdr_expr ;
898 -- Now typecheck the expression;
899 -- it might have a rank-2 type (e.g. :t runST)
900 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
901 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
902 tcSimplifyInteractive lie_top ;
904 let { all_expr_ty = mkForAllTys qtvs $
905 mkFunTys (map idType dict_ids) $
907 zonkTcType all_expr_ty
910 smpl_doc = ptext SLIT("main expression")
913 tcRnType just finds the kind of a type
917 -> InteractiveContext
920 tcRnType hsc_env ictxt rdr_type
921 = initTcPrintErrors hsc_env iNTERACTIVE $
922 setInteractiveContext ictxt $ do {
924 rn_type <- rnLHsType doc rdr_type ;
927 -- Now kind-check the type
928 (ty', kind) <- kcHsType rn_type ;
932 doc = ptext SLIT("In GHCi input")
938 %************************************************************************
940 More GHCi stuff, to do with browsing and getting info
942 %************************************************************************
946 mkExportEnv :: HscEnv -> [ModuleName] -- Expose these modules' exports only
948 mkExportEnv hsc_env exports
949 = do { mb_envs <- initTcPrintErrors hsc_env iNTERACTIVE $
950 mappM getModuleExports exports
952 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
953 Nothing -> return emptyGlobalRdrEnv
954 -- Some error; initTc will have printed it
957 getModuleExports :: ModuleName -> TcM GlobalRdrEnv
959 = do { iface <- load_iface mod
960 ; loadOrphanModules (dep_orphs (mi_deps iface))
961 -- Load any orphan-module interfaces,
962 -- so their instances are visible
963 ; avails <- exportsToAvails (mi_exports iface)
964 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
965 | avail <- avails, name <- availNames avail ] }
966 ; returnM (mkGlobalRdrEnv gres) }
968 vanillaProv :: ModuleName -> Provenance
969 -- We're building a GlobalRdrEnv as if the user imported
970 -- all the specified modules into the global interactive module
971 vanillaProv mod = Imported [ImportSpec mod mod False
972 (srcLocSpan interactiveSrcLoc)] False
978 -> InteractiveContext
979 -> ModuleName -- Module to inspect
980 -> Bool -- Grab just the exports, or the whole toplev
981 -> IO (Maybe [IfaceDecl])
983 getModuleContents hsc_env ictxt mod exports_only
984 = initTcPrintErrors hsc_env iNTERACTIVE (get_mod_contents exports_only)
986 get_mod_contents exports_only
987 | not exports_only -- We want the whole top-level type env
988 -- so it had better be a home module
990 ; case lookupModuleEnvByName hpt mod of
991 Just mod_info -> return (map toIfaceDecl $
994 md_types (hm_details mod_info))
995 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
996 -- This is a system error; the module should be in the HPT
999 | otherwise -- Want the exports only
1000 = do { iface <- load_iface mod
1001 ; avails <- exportsToAvails (mi_exports iface)
1002 ; mappM get_decl avails
1006 = do { thing <- tcLookupGlobal (availName avail)
1007 ; return (filter_decl (availOccs avail) (toIfaceDecl thing)) }
1009 ---------------------
1010 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
1011 = decl { ifSigs = filter (keep_sig occs) sigs }
1012 filter_decl occs decl@(IfaceData {ifCons = IfDataTyCon th cons})
1013 = decl { ifCons = IfDataTyCon th (filter (keep_con occs) cons) }
1014 filter_decl occs decl@(IfaceData {ifCons = IfNewTyCon con})
1015 | keep_con occs con = decl
1016 | otherwise = decl {ifCons = IfAbstractTyCon} -- Hmm?
1017 filter_decl occs decl
1020 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
1021 keep_con occs con = ifConOcc con `elem` occs
1023 availOccs avail = map nameOccName (availNames avail)
1025 wantToSee (AnId id) = not (isImplicitId id)
1026 wantToSee (ADataCon _) = False -- They'll come via their TyCon
1029 ---------------------
1030 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
1032 doc = ptext SLIT("context for compiling statements")
1034 ---------------------
1035 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1036 <+> quotes (ppr mod)
1040 tcRnGetInfo :: HscEnv
1041 -> InteractiveContext
1043 -> IO (Maybe [(IfaceDecl,
1045 [(IfaceInst, SrcLoc)])])
1046 -- Used to implemnent :info in GHCi
1048 -- Look up a RdrName and return all the TyThings it might be
1049 -- A capitalised RdrName is given to us in the DataName namespace,
1050 -- but we want to treat it as *both* a data constructor
1051 -- *and* as a type or class constructor;
1052 -- hence the call to dataTcOccs, and we return up to two results
1053 tcRnGetInfo hsc_env ictxt rdr_name
1054 = initTcPrintErrors hsc_env iNTERACTIVE $
1055 setInteractiveContext ictxt $ do {
1057 -- If the identifier is a constructor (begins with an
1058 -- upper-case letter), then we need to consider both
1059 -- constructor and type class identifiers.
1060 let { rdr_names = dataTcOccs rdr_name } ;
1062 -- results :: [(Messages, Maybe Name)]
1063 results <- mapM (tryTc . lookupOccRn) rdr_names ;
1065 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1066 -- The successful lookups will be (Just name)
1067 let { (warns_s, good_names) = unzip [ (msgs, name)
1068 | (msgs, Just name) <- results] ;
1069 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1071 -- Fail if nothing good happened, else add warnings
1072 if null good_names then
1073 -- No lookup succeeded, so
1074 -- pick the first error message and report it
1075 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1076 -- while the other is "X is not in scope",
1077 -- we definitely want the former; but we might pick the latter
1078 do { addMessages (head errs_s) ; failM }
1079 else -- Add deprecation warnings
1080 mapM_ addMessages warns_s ;
1082 -- And lookup up the entities, avoiding duplicates, which arise
1083 -- because constructors and record selectors are represented by
1084 -- their parent declaration
1085 let { do_one name = do { thing <- tcLookupGlobal name
1086 ; let decl = toIfaceDecl thing
1087 ; fixity <- lookupFixityRn name
1088 ; insts <- lookupInsts thing
1089 ; return (decl, fixity, getSrcLoc thing,
1090 map mk_inst insts) } ;
1091 -- For the SrcLoc, the 'thing' has better info than
1092 -- the 'name' because getting the former forced the
1093 -- declaration to be loaded into the cache
1094 mk_inst dfun = (dfunToIfaceInst dfun, getSrcLoc dfun) ;
1095 cmp (d1,_,_,_) (d2,_,_,_) = ifName d1 `compare` ifName d2 } ;
1096 results <- mapM do_one good_names ;
1097 return (fst (removeDups cmp results))
1100 lookupInsts :: TyThing -> TcM [DFunId]
1101 lookupInsts (AClass cls)
1102 = do { loadImportedInsts cls [] -- [] means load all instances for cls
1103 ; inst_envs <- tcGetInstEnvs
1104 ; return [df | (_,_,df) <- classInstances inst_envs cls] }
1106 lookupInsts (ATyCon tc)
1107 = do { eps <- getEps -- Load all instances for all classes that are
1108 -- in the type environment (which are all the ones
1109 -- we've seen in any interface file so far
1110 ; mapM_ (\c -> loadImportedInsts c [])
1111 (typeEnvClasses (eps_PTE eps))
1112 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1113 ; return (get home_ie ++ get pkg_ie) }
1115 get ie = [df | (_,_,df) <- instEnvElts ie, relevant df]
1116 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1117 tc_name = tyConName tc
1119 lookupInsts other = return []
1122 toIfaceDecl :: TyThing -> IfaceDecl
1124 = tyThingToIfaceDecl True -- Discard IdInfo
1125 emptyNameSet -- Show data cons
1126 ext_nm (munge thing)
1128 ext_nm n = ExtPkg (nameModuleName n) (nameOccName n)
1130 -- munge transforms a thing to it's "parent" thing
1131 munge (ADataCon dc) = ATyCon (dataConTyCon dc)
1132 munge (AnId id) = case globalIdDetails id of
1133 RecordSelId tc lbl -> ATyCon tc
1134 ClassOpId cls -> AClass cls
1136 munge other_thing = other_thing
1141 %************************************************************************
1145 %************************************************************************
1148 rnDump :: SDoc -> TcRn ()
1149 -- Dump, with a banner, if -ddump-rn
1150 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1152 tcDump :: TcGblEnv -> TcRn ()
1154 = do { dflags <- getDOpts ;
1156 -- Dump short output if -ddump-types or -ddump-tc
1157 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1158 (dumpTcRn short_dump) ;
1160 -- Dump bindings if -ddump-tc
1161 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1164 short_dump = pprTcGblEnv env
1165 full_dump = pprLHsBinds (tcg_binds env)
1166 -- NB: foreign x-d's have undefined's in their types;
1167 -- hence can't show the tc_fords
1170 = do { dflags <- getDOpts ;
1171 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1172 (dumpTcRn (pprModGuts mod_guts)) ;
1174 -- Dump bindings if -ddump-tc
1175 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1177 full_dump = pprCoreBindings (mg_binds mod_guts)
1179 -- It's unpleasant having both pprModGuts and pprModDetails here
1180 pprTcGblEnv :: TcGblEnv -> SDoc
1181 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1182 tcg_insts = dfun_ids,
1184 tcg_imports = imports })
1185 = vcat [ ppr_types dfun_ids type_env
1186 , ppr_insts dfun_ids
1187 , vcat (map ppr rules)
1188 , ppr_gen_tycons (typeEnvTyCons type_env)
1189 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1190 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1192 pprModGuts :: ModGuts -> SDoc
1193 pprModGuts (ModGuts { mg_types = type_env,
1195 = vcat [ ppr_types [] type_env,
1199 ppr_types :: [Var] -> TypeEnv -> SDoc
1200 ppr_types dfun_ids type_env
1201 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1203 ids = [id | id <- typeEnvIds type_env, want_sig id]
1204 want_sig id | opt_PprStyle_Debug = True
1205 | otherwise = isLocalId id &&
1206 isExternalName (idName id) &&
1207 not (id `elem` dfun_ids)
1208 -- isLocalId ignores data constructors, records selectors etc.
1209 -- The isExternalName ignores local dictionary and method bindings
1210 -- that the type checker has invented. Top-level user-defined things
1211 -- have External names.
1213 ppr_insts :: [Var] -> SDoc
1214 ppr_insts [] = empty
1215 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1217 ppr_sigs :: [Var] -> SDoc
1219 -- Print type signatures; sort by OccName
1220 = vcat (map ppr_sig (sortLe le_sig ids))
1222 le_sig id1 id2 = getOccName id1 <= getOccName id2
1223 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1225 ppr_rules :: [IdCoreRule] -> SDoc
1226 ppr_rules [] = empty
1227 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1228 nest 4 (pprIdRules rs),
1231 ppr_gen_tycons [] = empty
1232 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1233 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]