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 Packages ( moduleToPackageConfig, mkPackageId, package,
26 import DriverState ( v_MainModIs, v_MainFunIs )
27 import HsSyn ( HsModule(..), HsExtCore(..), HsGroup(..), LHsDecl, SpliceDecl(..), HsBind(..),
28 nlHsApp, nlHsVar, pprLHsBinds )
29 import RdrHsSyn ( findSplice )
31 import PrelNames ( runIOName, rootMainName, mAIN,
33 import RdrName ( RdrName, mkRdrUnqual, emptyGlobalRdrEnv,
35 import TcHsSyn ( zonkTopDecls )
36 import TcExpr ( tcInferRho )
38 import TcType ( tidyTopType, tcEqType, mkTyVarTys, substTyWith )
39 import Inst ( showLIE )
40 import TcBinds ( tcTopBinds )
41 import TcDefaults ( tcDefaults )
42 import TcEnv ( tcExtendGlobalValEnv )
43 import TcRules ( tcRules )
44 import TcForeign ( tcForeignImports, tcForeignExports )
45 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
46 import TcIface ( tcExtCoreBindings )
47 import TcSimplify ( tcSimplifyTop )
48 import TcTyClsDecls ( tcTyAndClassDecls )
49 import LoadIface ( loadOrphanModules, loadHiBootInterface )
50 import RnNames ( importsFromLocalDecls, rnImports, exportsFromAvail,
51 reportUnusedNames, reportDeprecations )
52 import RnEnv ( lookupSrcOcc_maybe )
53 import RnSource ( rnSrcDecls, rnTyClDecls, checkModDeprec )
54 import PprCore ( pprIdRules, pprCoreBindings )
55 import CoreSyn ( IdCoreRule, bindersOfBinds )
56 import DataCon ( dataConWrapId )
57 import ErrUtils ( Messages, mkDumpDoc, showPass )
58 import Id ( mkExportedLocalId, isLocalId, idName, idType )
60 import Module ( mkModule, moduleEnvElts )
61 import OccName ( mkVarOcc )
62 import Name ( Name, isExternalName, getSrcLoc, getOccName )
64 import TyCon ( tyConHasGenerics, isSynTyCon, getSynTyConDefn, tyConKind )
65 import SrcLoc ( srcLocSpan, Located(..), noLoc )
67 import HscTypes ( ModGuts(..), HscEnv(..), ExternalPackageState(..),
68 GhciMode(..), noDependencies,
69 Deprecs( NoDeprecs ), plusDeprecs,
70 ForeignStubs(NoStubs), TyThing(..),
71 TypeEnv, lookupTypeEnv,
72 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
76 import HsSyn ( HsStmtContext(..), Stmt(..), HsExpr(..), HsBindGroup(..),
77 LStmt, LHsExpr, LHsType, mkMatchGroup,
78 collectStmtsBinders, mkSimpleMatch,
79 nlLetStmt, nlExprStmt, nlBindStmt, nlResultStmt, nlVarPat )
80 import RdrName ( GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
81 Provenance(..), ImportSpec(..),
82 lookupLocalRdrEnv, extendLocalRdrEnv )
83 import RnSource ( addTcgDUs )
84 import TcHsSyn ( mkHsLet, zonkTopLExpr, zonkTopBndrs )
85 import TcHsType ( kcHsType )
86 import TcExpr ( tcCheckRho )
87 import TcIface ( loadImportedInsts )
88 import TcMType ( zonkTcType, zonkQuantifiedTyVar )
89 import TcUnify ( unifyTyConApp )
90 import TcMatches ( tcStmtsAndThen, TcStmtCtxt(..) )
91 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
92 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType,
93 isUnLiftedType, tyClsNamesOfDFunHead )
94 import TcEnv ( tcLookupTyCon, tcLookupId, tcLookupGlobal )
95 import RnTypes ( rnLHsType )
96 import Inst ( tcStdSyntaxName, tcGetInstEnvs )
97 import InstEnv ( DFunId, classInstances, instEnvElts )
98 import RnExpr ( rnStmts, rnLExpr )
99 import RnNames ( exportsToAvails )
100 import LoadIface ( loadSrcInterface )
101 import IfaceSyn ( IfaceDecl(..), IfaceClassOp(..), IfaceConDecl(..),
102 IfaceExtName(..), IfaceConDecls(..), IfaceInst(..),
103 tyThingToIfaceDecl, dfunToIfaceInst )
104 import IfaceEnv ( lookupOrig )
105 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
106 import Id ( Id, isImplicitId, setIdType, globalIdDetails )
107 import MkId ( unsafeCoerceId )
108 import DataCon ( dataConTyCon )
109 import TyCon ( tyConName )
110 import TysWiredIn ( mkListTy, unitTy )
111 import IdInfo ( GlobalIdDetails(..) )
112 import SrcLoc ( interactiveSrcLoc, unLoc )
114 import Var ( globaliseId )
115 import Name ( nameOccName, nameModule )
116 import NameEnv ( delListFromNameEnv )
117 import PrelNames ( iNTERACTIVE, ioTyConName, printName, monadNames, itName, returnIOName )
118 import Module ( Module, lookupModuleEnv )
119 import HscTypes ( InteractiveContext(..), HomeModInfo(..), typeEnvElts, typeEnvClasses,
120 availNames, availName, ModIface(..),
121 ModDetails(..), Dependencies(..) )
122 import BasicTypes ( RecFlag(..), Fixity )
123 import Bag ( unitBag )
124 import ListSetOps ( removeDups )
125 import Panic ( ghcError, GhcException(..) )
126 import SrcLoc ( SrcLoc )
129 import FastString ( mkFastString )
130 import Util ( sortLe )
131 import Bag ( unionBags, snocBag )
133 import Maybe ( isJust )
138 %************************************************************************
140 Typecheck and rename a module
142 %************************************************************************
147 -> Located (HsModule RdrName)
148 -> IO (Messages, Maybe TcGblEnv)
150 tcRnModule hsc_env (L loc (HsModule maybe_mod export_ies
151 import_decls local_decls mod_deprec))
152 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
154 let { this_mod = case maybe_mod of
156 -- 'module M where' is omitted
157 Just (L _ mod) -> mod } ;
160 initTc hsc_env this_mod $
163 checkForPackageModule (hsc_dflags hsc_env) this_mod;
165 -- Deal with imports; sets tcg_rdr_env, tcg_imports
166 (rdr_env, imports) <- rnImports import_decls ;
168 -- Record boot-file info in the EPS, so that it's
169 -- visible to loadHiBootInterface in tcRnSrcDecls,
170 -- and any other incrementally-performed imports
171 updateEps_ (\eps -> eps { eps_is_boot = imp_dep_mods imports }) ;
173 -- Update the gbl env
174 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
175 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
177 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
178 -- Fail if there are any errors so far
179 -- The error printing (if needed) takes advantage
180 -- of the tcg_env we have now set
183 -- Load any orphan-module interfaces, so that
184 -- their rules and instance decls will be found
185 loadOrphanModules (imp_orphs imports) ;
187 traceRn (text "rn1a") ;
188 -- Rename and type check the declarations
189 tcg_env <- tcRnSrcDecls local_decls ;
190 setGblEnv tcg_env $ do {
192 traceRn (text "rn3") ;
194 -- Report the use of any deprecated things
195 -- We do this before processsing the export list so
196 -- that we don't bleat about re-exporting a deprecated
197 -- thing (especially via 'module Foo' export item)
198 -- Only uses in the body of the module are complained about
199 reportDeprecations tcg_env ;
201 -- Process the export list
202 exports <- exportsFromAvail (isJust maybe_mod) export_ies ;
204 -- Check whether the entire module is deprecated
205 -- This happens only once per module
206 let { mod_deprecs = checkModDeprec mod_deprec } ;
208 -- Add exports and deprecations to envt
209 let { final_env = tcg_env { tcg_exports = exports,
210 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
211 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
213 -- A module deprecation over-rides the earlier ones
216 -- Report unused names
217 reportUnusedNames final_env ;
219 -- Dump output and return
224 -- This is really a sanity check that the user has given -package-name
225 -- if necessary. -package-name is only necessary when the package database
226 -- already contains the current package, because then we can't tell
227 -- whether a given module is in the current package or not, without knowing
228 -- the name of the current package.
229 checkForPackageModule dflags this_mod
230 | not (isHomeModule dflags this_mod),
231 Just (pkg,_) <- moduleToPackageConfig dflags this_mod =
233 ppr_pkg = ppr (mkPackageId (package pkg))
235 addErr (ptext SLIT("Module") <+> quotes (ppr this_mod) <+>
236 ptext SLIT("is a member of package") <+> ppr_pkg <> char '.' $$
237 ptext SLIT("To compile this module, please use -ignore-package") <+> ppr_pkg <> char '.')
238 | otherwise = return ()
242 %************************************************************************
244 Type-checking external-core modules
246 %************************************************************************
249 tcRnExtCore :: HscEnv
251 -> IO (Messages, Maybe ModGuts)
252 -- Nothing => some error occurred
254 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
255 -- The decls are IfaceDecls; all names are original names
256 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
258 initTc hsc_env this_mod $ do {
260 let { ldecls = map noLoc decls } ;
262 -- Deal with the type declarations; first bring their stuff
263 -- into scope, then rname them, then type check them
264 (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup ldecls) ;
266 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
267 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
270 rn_decls <- rnTyClDecls ldecls ;
273 -- Dump trace of renaming part
274 rnDump (ppr rn_decls) ;
276 -- Typecheck them all together so that
277 -- any mutually recursive types are done right
278 tcg_env <- checkNoErrs (tcTyAndClassDecls [{- no boot names -}] rn_decls) ;
279 -- Make the new type env available to stuff slurped from interface files
281 setGblEnv tcg_env $ do {
283 -- Now the core bindings
284 core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;
288 bndrs = bindersOfBinds core_binds ;
289 my_exports = mkNameSet (map idName bndrs) ;
290 -- ToDo: export the data types also?
292 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
294 mod_guts = ModGuts { mg_module = this_mod,
295 mg_usages = [], -- ToDo: compute usage
296 mg_dir_imps = [], -- ??
297 mg_deps = noDependencies, -- ??
298 mg_exports = my_exports,
299 mg_types = final_type_env,
300 mg_insts = tcg_insts tcg_env,
302 mg_binds = core_binds,
305 mg_rdr_env = emptyGlobalRdrEnv,
306 mg_fix_env = emptyFixityEnv,
307 mg_deprecs = NoDeprecs,
311 tcCoreDump mod_guts ;
316 mkFakeGroup decls -- Rather clumsy; lots of unused fields
317 = HsGroup { hs_tyclds = decls, -- This is the one we want
318 hs_valds = [], hs_fords = [],
319 hs_instds = [], hs_fixds = [], hs_depds = [],
320 hs_ruleds = [], hs_defds = [] }
324 %************************************************************************
326 Type-checking the top level of a module
328 %************************************************************************
331 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
332 -- Returns the variables free in the decls
333 -- Reason: solely to report unused imports and bindings
335 = do { -- Load the hi-boot interface for this module, if any
336 -- We do this now so that the boot_names can be passed
337 -- to tcTyAndClassDecls, because the boot_names are
338 -- automatically considered to be loop breakers
339 boot_names <- loadHiBootInterface ;
341 -- Do all the declarations
342 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_names decls) ;
344 -- tcSimplifyTop deals with constant or ambiguous InstIds.
345 -- How could there be ambiguous ones? They can only arise if a
346 -- top-level decl falls under the monomorphism
347 -- restriction, and no subsequent decl instantiates its
348 -- type. (Usually, ambiguous type variables are resolved
349 -- during the generalisation step.)
350 traceTc (text "Tc8") ;
351 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
352 -- Setting the global env exposes the instances to tcSimplifyTop
353 -- Setting the local env exposes the local Ids to tcSimplifyTop,
354 -- so that we get better error messages (monomorphism restriction)
356 -- Backsubstitution. This must be done last.
357 -- Even tcSimplifyTop may do some unification.
358 traceTc (text "Tc9") ;
359 let { (tcg_env, _) = tc_envs ;
360 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
361 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
363 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
366 let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
368 -- Compre the hi-boot iface (if any) with the real thing
369 checkHiBootIface final_type_env boot_names ;
371 -- Make the new type env available to stuff slurped from interface files
372 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
374 return (tcg_env { tcg_type_env = final_type_env,
375 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' })
378 tc_rn_src_decls :: [Name] -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
379 -- Loops around dealing with each top level inter-splice group
380 -- in turn, until it's dealt with the entire module
381 tc_rn_src_decls boot_names ds
382 = do { let { (first_group, group_tail) = findSplice ds } ;
383 -- If ds is [] we get ([], Nothing)
385 -- Type check the decls up to, but not including, the first splice
386 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_names first_group ;
388 -- Bale out if errors; for example, error recovery when checking
389 -- the RHS of 'main' can mean that 'main' is not in the envt for
390 -- the subsequent checkMain test
395 -- If there is no splice, we're nearly done
397 Nothing -> do { -- Last thing: check for `main'
398 tcg_env <- checkMain ;
399 return (tcg_env, tcl_env)
402 -- If there's a splice, we must carry on
403 Just (SpliceDecl splice_expr, rest_ds) -> do {
405 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
408 -- Rename the splice expression, and get its supporting decls
409 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
410 failIfErrsM ; -- Don't typecheck if renaming failed
412 -- Execute the splice
413 spliced_decls <- tcSpliceDecls rn_splice_expr ;
415 -- Glue them on the front of the remaining decls and loop
416 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
417 tc_rn_src_decls boot_names (spliced_decls ++ rest_ds)
422 %************************************************************************
424 Comparing the hi-boot interface with the real thing
426 %************************************************************************
428 In both one-shot mode and GHCi mode, hi-boot interfaces are demand-loaded
429 into the External Package Table. Once we've typechecked the body of the
430 module, we want to compare what we've found (gathered in a TypeEnv) with
431 the hi-boot stuff in the EPT. We do so here, using the export list of
432 the hi-boot interface as our checklist.
435 checkHiBootIface :: TypeEnv -> [Name] -> TcM ()
436 -- Compare the hi-boot file for this module (if there is one)
437 -- with the type environment we've just come up with
438 -- In the common case where there is no hi-boot file, the list
439 -- of boot_names is empty.
440 checkHiBootIface env boot_names
441 = mapM_ (check_one env) boot_names
444 check_one local_env name
447 -- Look up the hi-boot one;
448 -- it should jolly well be there (else GHC bug)
449 ; case lookupTypeEnv (eps_PTE eps) name of {
450 Nothing -> pprPanic "checkHiBootIface" (ppr name) ;
453 -- Look it up in the local type env
454 -- It should be there, but it's a programmer error if not
455 case lookupTypeEnv local_env name of
456 Nothing -> addErrTc (missingBootThing boot_thing)
457 Just real_thing -> check_thing boot_thing real_thing
461 check_thing (ATyCon boot_tc) (ATyCon real_tc)
462 | isSynTyCon boot_tc && isSynTyCon real_tc,
463 defn1 `tcEqType` substTyWith tvs2 (mkTyVarTys tvs1) defn2
466 | tyConKind boot_tc == tyConKind real_tc
469 (tvs1, defn1) = getSynTyConDefn boot_tc
470 (tvs2, defn2) = getSynTyConDefn boot_tc
472 check_thing (AnId boot_id) (AnId real_id)
473 | idType boot_id `tcEqType` idType real_id
476 check_thing (ADataCon dc1) (ADataCon dc2)
477 | idType (dataConWrapId dc1) `tcEqType` idType (dataConWrapId dc2)
480 -- Can't declare a class in a hi-boot file
482 check_thing boot_thing real_thing -- Default case; failure
483 = addErrAt (srcLocSpan (getSrcLoc real_thing))
484 (bootMisMatch real_thing)
487 missingBootThing thing
488 = ppr thing <+> ptext SLIT("is defined in the hi-boot file, but not in the module")
490 = ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hi-boot file")
494 %************************************************************************
496 Type-checking the top level of a module
498 %************************************************************************
500 tcRnGroup takes a bunch of top-level source-code declarations, and
502 * gets supporting declarations from interface files
505 * and augments the TcGblEnv with the results
507 In Template Haskell it may be called repeatedly for each group of
508 declarations. It expects there to be an incoming TcGblEnv in the
509 monad; it augments it and returns the new TcGblEnv.
512 tcRnGroup :: [Name] -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
513 -- Returns the variables free in the decls, for unused-binding reporting
514 tcRnGroup boot_names decls
515 = do { -- Rename the declarations
516 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
517 setGblEnv tcg_env $ do {
519 -- Typecheck the declarations
520 tcTopSrcDecls boot_names rn_decls
523 ------------------------------------------------
524 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
526 = do { -- Bring top level binders into scope
527 (rdr_env, imports) <- importsFromLocalDecls group ;
528 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
529 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
532 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
533 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
535 -- Rename the source decls
536 (tcg_env, rn_decls) <- rnSrcDecls group ;
539 -- Dump trace of renaming part
540 rnDump (ppr rn_decls) ;
542 return (tcg_env, rn_decls)
545 ------------------------------------------------
546 tcTopSrcDecls :: [Name] -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
547 tcTopSrcDecls boot_names
548 (HsGroup { hs_tyclds = tycl_decls,
549 hs_instds = inst_decls,
550 hs_fords = foreign_decls,
551 hs_defds = default_decls,
552 hs_ruleds = rule_decls,
553 hs_valds = val_binds })
554 = do { -- Type-check the type and class decls, and all imported decls
555 -- The latter come in via tycl_decls
556 traceTc (text "Tc2") ;
558 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_names tycl_decls) ;
559 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
560 -- an error we'd better stop now, to avoid a cascade
562 -- Make these type and class decls available to stuff slurped from interface files
563 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
566 setGblEnv tcg_env $ do {
567 -- Source-language instances, including derivings,
568 -- and import the supporting declarations
569 traceTc (text "Tc3") ;
570 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
571 setGblEnv tcg_env $ do {
573 -- Foreign import declarations next. No zonking necessary
574 -- here; we can tuck them straight into the global environment.
575 traceTc (text "Tc4") ;
576 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
577 tcExtendGlobalValEnv fi_ids $ do {
579 -- Default declarations
580 traceTc (text "Tc4a") ;
581 default_tys <- tcDefaults default_decls ;
582 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
584 -- Value declarations next
585 -- We also typecheck any extra binds that came out
586 -- of the "deriving" process (deriv_binds)
587 traceTc (text "Tc5") ;
588 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
589 setLclTypeEnv lcl_env $ do {
591 -- Second pass over class and instance declarations,
592 traceTc (text "Tc6") ;
593 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
594 showLIE (text "after instDecls2") ;
597 -- They need to be zonked, so we return them
598 traceTc (text "Tc7") ;
599 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
602 rules <- tcRules rule_decls ;
605 traceTc (text "Tc7a") ;
606 tcg_env <- getGblEnv ;
607 let { all_binds = tc_val_binds `unionBags`
608 inst_binds `unionBags`
611 -- Extend the GblEnv with the (as yet un-zonked)
612 -- bindings, rules, foreign decls
613 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
614 tcg_rules = tcg_rules tcg_env ++ rules,
615 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
616 return (tcg_env', lcl_env)
621 %************************************************************************
625 %************************************************************************
629 = do { ghci_mode <- getGhciMode ;
630 tcg_env <- getGblEnv ;
632 mb_main_mod <- readMutVar v_MainModIs ;
633 mb_main_fn <- readMutVar v_MainFunIs ;
634 let { main_mod = case mb_main_mod of {
635 Just mod -> mkModule mod ;
637 main_fn = case mb_main_fn of {
638 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
639 Nothing -> main_RDR_Unqual } } ;
641 check_main ghci_mode tcg_env main_mod main_fn
645 check_main ghci_mode tcg_env main_mod main_fn
646 -- If we are in module Main, check that 'main' is defined.
647 -- It may be imported from another module!
650 -- Blimey: a whole page of code to do this...
655 = addErrCtxt mainCtxt $
656 do { mb_main <- lookupSrcOcc_maybe main_fn
657 -- Check that 'main' is in scope
658 -- It might be imported from another module!
660 Nothing -> do { complain_no_main
663 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
664 -- :Main.main :: IO () = runIO main
666 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
669 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
670 main_bind = noLoc (VarBind root_main_id main_expr) }
672 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
674 tcg_dus = tcg_dus tcg_env
675 `plusDU` usesOnly (unitFV main_name)
676 -- Record the use of 'main', so that we don't
677 -- complain about it being defined but not used
681 mod = tcg_mod tcg_env
683 complain_no_main | ghci_mode == Interactive = return ()
684 | otherwise = failWithTc noMainMsg
685 -- In interactive mode, don't worry about the absence of 'main'
686 -- In other modes, fail altogether, so that we don't go on
687 -- and complain a second time when processing the export list.
689 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
690 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
691 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
695 %*********************************************************
699 %*********************************************************
703 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
704 setInteractiveContext icxt thing_inside
705 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
706 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
707 tcg_type_env = ic_type_env icxt}) $
708 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
715 -> InteractiveContext
717 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
718 -- The returned [Name] is the same as the input except for
719 -- ExprStmt, in which case the returned [Name] is [itName]
721 -- The returned TypecheckedHsExpr is of type IO [ () ],
722 -- a list of the bound values, coerced to ().
724 tcRnStmt hsc_env ictxt rdr_stmt
725 = initTcPrintErrors hsc_env iNTERACTIVE $
726 setInteractiveContext ictxt $ do {
728 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
729 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
730 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
733 -- The real work is done here
734 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
736 traceTc (text "tcs 1") ;
737 let { -- (a) Make all the bound ids "global" ids, now that
738 -- they're notionally top-level bindings. This is
739 -- important: otherwise when we come to compile an expression
740 -- using these ids later, the byte code generator will consider
741 -- the occurrences to be free rather than global.
743 -- (b) Tidy their types; this is important, because :info may
744 -- ask to look at them, and :info expects the things it looks
745 -- up to have tidy types
746 global_ids = map globaliseAndTidy bound_ids ;
748 -- Update the interactive context
749 rn_env = ic_rn_local_env ictxt ;
750 type_env = ic_type_env ictxt ;
752 bound_names = map idName global_ids ;
753 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
755 -- Remove any shadowed bindings from the type_env;
756 -- they are inaccessible but might, I suppose, cause
757 -- a space leak if we leave them there
758 shadowed = [ n | name <- bound_names,
759 let rdr_name = mkRdrUnqual (nameOccName name),
760 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
762 filtered_type_env = delListFromNameEnv type_env shadowed ;
763 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
765 new_ic = ictxt { ic_rn_local_env = new_rn_env,
766 ic_type_env = new_type_env }
769 dumpOptTcRn Opt_D_dump_tc
770 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
771 text "Typechecked expr" <+> ppr tc_expr]) ;
773 returnM (new_ic, bound_names, tc_expr)
776 globaliseAndTidy :: Id -> Id
778 -- Give the Id a Global Name, and tidy its type
779 = setIdType (globaliseId VanillaGlobal id) tidy_type
781 tidy_type = tidyTopType (idType id)
784 Here is the grand plan, implemented in tcUserStmt
786 What you type The IO [HValue] that hscStmt returns
787 ------------- ------------------------------------
788 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
791 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
794 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
795 [NB: result not printed] bindings: [it]
797 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
798 result showable) bindings: [it]
800 expr (of non-IO type,
801 result not showable) ==> error
805 ---------------------------
806 tcUserStmt :: LStmt Name -> TcM ([Id], LHsExpr Id)
807 tcUserStmt (L _ (ExprStmt expr _))
808 = newUnique `thenM` \ uniq ->
810 fresh_it = itName uniq
811 the_bind = noLoc $ FunBind (noLoc fresh_it) False
812 (mkMatchGroup [mkSimpleMatch [] expr])
814 tryTcLIE_ (do { -- Try this if the other fails
815 traceTc (text "tcs 1b") ;
817 nlLetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive],
818 nlExprStmt (nlHsApp (nlHsVar printName)
821 (do { -- Try this first
822 traceTc (text "tcs 1a") ;
823 tc_stmts [nlBindStmt (nlVarPat fresh_it) expr] })
825 tcUserStmt stmt = tc_stmts [stmt]
827 ---------------------------
829 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
831 ret_ty = mkListTy unitTy ;
832 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
834 names = map unLoc (collectStmtsBinders stmts) ;
836 stmt_ctxt = SC { sc_what = DoExpr,
838 sc_body = check_body,
841 infer_rhs rhs = do { (rhs', rhs_ty) <- tcInferRho rhs
842 ; [pat_ty] <- unifyTyConApp ioTyCon rhs_ty
843 ; return (rhs', pat_ty) } ;
844 check_body body = tcCheckRho body io_ret_ty ;
846 -- mk_return builds the expression
847 -- returnIO @ [()] [coerce () x, .., coerce () z]
849 -- Despite the inconvenience of building the type applications etc,
850 -- this *has* to be done in type-annotated post-typecheck form
851 -- because we are going to return a list of *polymorphic* values
852 -- coerced to type (). If we built a *source* stmt
853 -- return [coerce x, ..., coerce z]
854 -- then the type checker would instantiate x..z, and we wouldn't
855 -- get their *polymorphic* values. (And we'd get ambiguity errs
856 -- if they were overloaded, since they aren't applied to anything.)
857 mk_return ret_id ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
858 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
859 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
862 io_ty = mkTyConApp ioTyCon []
865 -- OK, we're ready to typecheck the stmts
866 traceTc (text "tcs 2") ;
867 ((ids, tc_expr), lie) <- getLIE $ do {
868 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
870 -- Look up the names right in the middle,
871 -- where they will all be in scope
872 ids <- mappM tcLookupId names ;
873 ret_id <- tcLookupId returnIOName ; -- return @ IO
874 return (ids, [nlResultStmt (mk_return ret_id ids)]) } ;
876 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
877 return (ids, noLoc (HsDo DoExpr tc_stmts io_ids io_ret_ty))
880 -- Simplify the context right here, so that we fail
881 -- if there aren't enough instances. Notably, when we see
883 -- we use recoverTc_ to try it <- e
884 -- and then let it = e
885 -- It's the simplify step that rejects the first.
886 traceTc (text "tcs 3") ;
887 const_binds <- tcSimplifyInteractive lie ;
889 -- Build result expression and zonk it
890 let { expr = mkHsLet const_binds tc_expr } ;
891 zonked_expr <- zonkTopLExpr expr ;
892 zonked_ids <- zonkTopBndrs ids ;
894 -- None of the Ids should be of unboxed type, because we
895 -- cast them all to HValues in the end!
896 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
898 return (zonked_ids, zonked_expr)
901 combine stmt (ids, stmts) = (ids, stmt:stmts)
902 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
903 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
907 tcRnExpr just finds the type of an expression
911 -> InteractiveContext
914 tcRnExpr hsc_env ictxt rdr_expr
915 = initTcPrintErrors hsc_env iNTERACTIVE $
916 setInteractiveContext ictxt $ do {
918 (rn_expr, fvs) <- rnLExpr rdr_expr ;
921 -- Now typecheck the expression;
922 -- it might have a rank-2 type (e.g. :t runST)
923 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
924 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
925 tcSimplifyInteractive lie_top ;
926 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
928 let { all_expr_ty = mkForAllTys qtvs' $
929 mkFunTys (map idType dict_ids) $
931 zonkTcType all_expr_ty
934 smpl_doc = ptext SLIT("main expression")
937 tcRnType just finds the kind of a type
941 -> InteractiveContext
944 tcRnType hsc_env ictxt rdr_type
945 = initTcPrintErrors hsc_env iNTERACTIVE $
946 setInteractiveContext ictxt $ do {
948 rn_type <- rnLHsType doc rdr_type ;
951 -- Now kind-check the type
952 (ty', kind) <- kcHsType rn_type ;
956 doc = ptext SLIT("In GHCi input")
962 %************************************************************************
964 More GHCi stuff, to do with browsing and getting info
966 %************************************************************************
970 mkExportEnv :: HscEnv -> [Module] -- Expose these modules' exports only
972 mkExportEnv hsc_env exports
973 = do { mb_envs <- initTcPrintErrors hsc_env iNTERACTIVE $
974 mappM getModuleExports exports
976 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
977 Nothing -> return emptyGlobalRdrEnv
978 -- Some error; initTc will have printed it
981 getModuleExports :: Module -> TcM GlobalRdrEnv
983 = do { iface <- load_iface mod
984 ; loadOrphanModules (dep_orphs (mi_deps iface))
985 -- Load any orphan-module interfaces,
986 -- so their instances are visible
987 ; names <- exportsToAvails (mi_exports iface)
988 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
989 | name <- nameSetToList names ] }
990 ; returnM (mkGlobalRdrEnv gres) }
992 vanillaProv :: Module -> Provenance
993 -- We're building a GlobalRdrEnv as if the user imported
994 -- all the specified modules into the global interactive module
995 vanillaProv mod = Imported [ImportSpec mod mod False
996 (srcLocSpan interactiveSrcLoc)] False
1002 -> InteractiveContext
1003 -> Module -- Module to inspect
1004 -> Bool -- Grab just the exports, or the whole toplev
1005 -> IO (Maybe [IfaceDecl])
1007 getModuleContents hsc_env ictxt mod exports_only
1008 = initTcPrintErrors hsc_env iNTERACTIVE (get_mod_contents exports_only)
1010 get_mod_contents exports_only
1011 | not exports_only -- We want the whole top-level type env
1012 -- so it had better be a home module
1013 = do { hpt <- getHpt
1014 ; case lookupModuleEnv hpt mod of
1015 Just mod_info -> return (map toIfaceDecl $
1018 md_types (hm_details mod_info))
1019 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
1020 -- This is a system error; the module should be in the HPT
1023 | otherwise -- Want the exports only
1024 = do { iface <- load_iface mod
1025 ; mappM get_decl [ (mod,avail) | (mod, avails) <- mi_exports iface
1029 get_decl (mod, avail)
1030 = do { main_name <- lookupOrig mod (availName avail)
1031 ; thing <- tcLookupGlobal main_name
1032 ; return (filter_decl (availNames avail) (toIfaceDecl thing)) }
1034 ---------------------
1035 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
1036 = decl { ifSigs = filter (keep_sig occs) sigs }
1037 filter_decl occs decl@(IfaceData {ifCons = IfDataTyCon th cons})
1038 = decl { ifCons = IfDataTyCon th (filter (keep_con occs) cons) }
1039 filter_decl occs decl@(IfaceData {ifCons = IfNewTyCon con})
1040 | keep_con occs con = decl
1041 | otherwise = decl {ifCons = IfAbstractTyCon} -- Hmm?
1042 filter_decl occs decl
1045 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
1046 keep_con occs con = ifConOcc con `elem` occs
1048 wantToSee (AnId id) = not (isImplicitId id)
1049 wantToSee (ADataCon _) = False -- They'll come via their TyCon
1052 ---------------------
1053 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
1055 doc = ptext SLIT("context for compiling statements")
1057 ---------------------
1058 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1059 <+> quotes (ppr mod)
1063 tcRnGetInfo :: HscEnv
1064 -> InteractiveContext
1066 -> IO (Maybe [(IfaceDecl,
1068 [(IfaceInst, SrcLoc)])])
1069 -- Used to implemnent :info in GHCi
1071 -- Look up a RdrName and return all the TyThings it might be
1072 -- A capitalised RdrName is given to us in the DataName namespace,
1073 -- but we want to treat it as *both* a data constructor
1074 -- *and* as a type or class constructor;
1075 -- hence the call to dataTcOccs, and we return up to two results
1076 tcRnGetInfo hsc_env ictxt rdr_name
1077 = initTcPrintErrors hsc_env iNTERACTIVE $
1078 setInteractiveContext ictxt $ do {
1080 -- If the identifier is a constructor (begins with an
1081 -- upper-case letter), then we need to consider both
1082 -- constructor and type class identifiers.
1083 let { rdr_names = dataTcOccs rdr_name } ;
1085 -- results :: [(Messages, Maybe Name)]
1086 results <- mapM (tryTc . lookupOccRn) rdr_names ;
1088 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1089 -- The successful lookups will be (Just name)
1090 let { (warns_s, good_names) = unzip [ (msgs, name)
1091 | (msgs, Just name) <- results] ;
1092 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1094 -- Fail if nothing good happened, else add warnings
1095 if null good_names then
1096 -- No lookup succeeded, so
1097 -- pick the first error message and report it
1098 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1099 -- while the other is "X is not in scope",
1100 -- we definitely want the former; but we might pick the latter
1101 do { addMessages (head errs_s) ; failM }
1102 else -- Add deprecation warnings
1103 mapM_ addMessages warns_s ;
1105 -- And lookup up the entities, avoiding duplicates, which arise
1106 -- because constructors and record selectors are represented by
1107 -- their parent declaration
1108 let { do_one name = do { thing <- tcLookupGlobal name
1109 ; let decl = toIfaceDecl thing
1110 ; fixity <- lookupFixityRn name
1111 ; insts <- lookupInsts thing
1112 ; return (decl, fixity, getSrcLoc thing,
1113 map mk_inst insts) } ;
1114 -- For the SrcLoc, the 'thing' has better info than
1115 -- the 'name' because getting the former forced the
1116 -- declaration to be loaded into the cache
1117 mk_inst dfun = (dfunToIfaceInst dfun, getSrcLoc dfun) ;
1118 cmp (d1,_,_,_) (d2,_,_,_) = ifName d1 `compare` ifName d2 } ;
1119 results <- mapM do_one good_names ;
1120 return (fst (removeDups cmp results))
1123 lookupInsts :: TyThing -> TcM [DFunId]
1124 lookupInsts (AClass cls)
1125 = do { loadImportedInsts cls [] -- [] means load all instances for cls
1126 ; inst_envs <- tcGetInstEnvs
1127 ; return [df | (_,_,df) <- classInstances inst_envs cls] }
1129 lookupInsts (ATyCon tc)
1130 = do { eps <- getEps -- Load all instances for all classes that are
1131 -- in the type environment (which are all the ones
1132 -- we've seen in any interface file so far
1133 ; mapM_ (\c -> loadImportedInsts c [])
1134 (typeEnvClasses (eps_PTE eps))
1135 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1136 ; return (get home_ie ++ get pkg_ie) }
1138 get ie = [df | (_,_,df) <- instEnvElts ie, relevant df]
1139 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1140 tc_name = tyConName tc
1142 lookupInsts other = return []
1145 toIfaceDecl :: TyThing -> IfaceDecl
1147 = tyThingToIfaceDecl True -- Discard IdInfo
1148 emptyNameSet -- Show data cons
1149 ext_nm (munge thing)
1151 ext_nm n = ExtPkg (nameModule n) (nameOccName n)
1153 -- munge transforms a thing to it's "parent" thing
1154 munge (ADataCon dc) = ATyCon (dataConTyCon dc)
1155 munge (AnId id) = case globalIdDetails id of
1156 RecordSelId tc lbl -> ATyCon tc
1157 ClassOpId cls -> AClass cls
1159 munge other_thing = other_thing
1164 %************************************************************************
1168 %************************************************************************
1171 rnDump :: SDoc -> TcRn ()
1172 -- Dump, with a banner, if -ddump-rn
1173 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1175 tcDump :: TcGblEnv -> TcRn ()
1177 = do { dflags <- getDOpts ;
1179 -- Dump short output if -ddump-types or -ddump-tc
1180 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1181 (dumpTcRn short_dump) ;
1183 -- Dump bindings if -ddump-tc
1184 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1187 short_dump = pprTcGblEnv env
1188 full_dump = pprLHsBinds (tcg_binds env)
1189 -- NB: foreign x-d's have undefined's in their types;
1190 -- hence can't show the tc_fords
1193 = do { dflags <- getDOpts ;
1194 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1195 (dumpTcRn (pprModGuts mod_guts)) ;
1197 -- Dump bindings if -ddump-tc
1198 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1200 full_dump = pprCoreBindings (mg_binds mod_guts)
1202 -- It's unpleasant having both pprModGuts and pprModDetails here
1203 pprTcGblEnv :: TcGblEnv -> SDoc
1204 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1205 tcg_insts = dfun_ids,
1207 tcg_imports = imports })
1208 = vcat [ ppr_types dfun_ids type_env
1209 , ppr_insts dfun_ids
1210 , vcat (map ppr rules)
1211 , ppr_gen_tycons (typeEnvTyCons type_env)
1212 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1213 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1215 pprModGuts :: ModGuts -> SDoc
1216 pprModGuts (ModGuts { mg_types = type_env,
1218 = vcat [ ppr_types [] type_env,
1222 ppr_types :: [Var] -> TypeEnv -> SDoc
1223 ppr_types dfun_ids type_env
1224 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1226 ids = [id | id <- typeEnvIds type_env, want_sig id]
1227 want_sig id | opt_PprStyle_Debug = True
1228 | otherwise = isLocalId id &&
1229 isExternalName (idName id) &&
1230 not (id `elem` dfun_ids)
1231 -- isLocalId ignores data constructors, records selectors etc.
1232 -- The isExternalName ignores local dictionary and method bindings
1233 -- that the type checker has invented. Top-level user-defined things
1234 -- have External names.
1236 ppr_insts :: [Var] -> SDoc
1237 ppr_insts [] = empty
1238 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1240 ppr_sigs :: [Var] -> SDoc
1242 -- Print type signatures; sort by OccName
1243 = vcat (map ppr_sig (sortLe le_sig ids))
1245 le_sig id1 id2 = getOccName id1 <= getOccName id2
1246 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1248 ppr_rules :: [IdCoreRule] -> SDoc
1249 ppr_rules [] = empty
1250 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1251 nest 4 (pprIdRules rs),
1254 ppr_gen_tycons [] = empty
1255 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1256 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]