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 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 export_ies
150 import_decls local_decls mod_deprec))
151 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
153 let { this_mod = case maybe_mod of
155 -- 'module M where' is omitted
156 Just (L _ mod) -> mod } ;
159 initTc hsc_env this_mod $
162 checkForPackageModule (hsc_dflags hsc_env) this_mod;
164 -- Deal with imports; sets tcg_rdr_env, tcg_imports
165 (rdr_env, imports) <- rnImports import_decls ;
167 -- Record boot-file info in the EPS, so that it's
168 -- visible to loadHiBootInterface in tcRnSrcDecls,
169 -- and any other incrementally-performed imports
170 updateEps_ (\eps -> eps { eps_is_boot = imp_dep_mods imports }) ;
172 -- Update the gbl env
173 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
174 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
176 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
177 -- Fail if there are any errors so far
178 -- The error printing (if needed) takes advantage
179 -- of the tcg_env we have now set
182 -- Load any orphan-module interfaces, so that
183 -- their rules and instance decls will be found
184 loadOrphanModules (imp_orphs imports) ;
186 traceRn (text "rn1a") ;
187 -- Rename and type check the declarations
188 tcg_env <- tcRnSrcDecls local_decls ;
189 setGblEnv tcg_env $ do {
191 traceRn (text "rn3") ;
193 -- Report the use of any deprecated things
194 -- We do this before processsing the export list so
195 -- that we don't bleat about re-exporting a deprecated
196 -- thing (especially via 'module Foo' export item)
197 -- Only uses in the body of the module are complained about
198 reportDeprecations tcg_env ;
200 -- Process the export list
201 exports <- exportsFromAvail (isJust maybe_mod) export_ies ;
203 -- Check whether the entire module is deprecated
204 -- This happens only once per module
205 let { mod_deprecs = checkModDeprec mod_deprec } ;
207 -- Add exports and deprecations to envt
208 let { final_env = tcg_env { tcg_exports = exports,
209 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
210 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
212 -- A module deprecation over-rides the earlier ones
215 -- Report unused names
216 reportUnusedNames final_env ;
218 -- Dump output and return
223 -- This is really a sanity check that the user has given -package-name
224 -- if necessary. -package-name is only necessary when the package database
225 -- already contains the current package, because then we can't tell
226 -- whether a given module is in the current package or not, without knowing
227 -- the name of the current package.
228 checkForPackageModule dflags this_mod
229 | not (isHomeModule dflags this_mod),
230 Just (pkg,_) <- moduleToPackageConfig dflags this_mod =
232 ppr_pkg = ppr (mkPackageId (package pkg))
234 addErr (ptext SLIT("Module") <+> quotes (ppr this_mod) <+>
235 ptext SLIT("is a member of package") <+> ppr_pkg <> char '.' $$
236 ptext SLIT("To compile this module, please use -ignore-package") <+> ppr_pkg <> char '.')
237 | otherwise = return ()
241 %************************************************************************
243 Type-checking external-core modules
245 %************************************************************************
248 tcRnExtCore :: HscEnv
250 -> IO (Messages, Maybe ModGuts)
251 -- Nothing => some error occurred
253 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
254 -- The decls are IfaceDecls; all names are original names
255 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
257 initTc hsc_env this_mod $ do {
259 let { ldecls = map noLoc decls } ;
261 -- Deal with the type declarations; first bring their stuff
262 -- into scope, then rname them, then type check them
263 (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup ldecls) ;
265 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
266 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
269 rn_decls <- rnTyClDecls ldecls ;
272 -- Dump trace of renaming part
273 rnDump (ppr rn_decls) ;
275 -- Typecheck them all together so that
276 -- any mutually recursive types are done right
277 tcg_env <- checkNoErrs (tcTyAndClassDecls [{- no boot names -}] rn_decls) ;
278 -- Make the new type env available to stuff slurped from interface files
280 setGblEnv tcg_env $ do {
282 -- Now the core bindings
283 core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;
287 bndrs = bindersOfBinds core_binds ;
288 my_exports = mkNameSet (map idName bndrs) ;
289 -- ToDo: export the data types also?
291 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
293 mod_guts = ModGuts { mg_module = this_mod,
294 mg_usages = [], -- ToDo: compute usage
295 mg_dir_imps = [], -- ??
296 mg_deps = noDependencies, -- ??
297 mg_exports = my_exports,
298 mg_types = final_type_env,
299 mg_insts = tcg_insts tcg_env,
301 mg_binds = core_binds,
304 mg_rdr_env = emptyGlobalRdrEnv,
305 mg_fix_env = emptyFixityEnv,
306 mg_deprecs = NoDeprecs,
310 tcCoreDump mod_guts ;
315 mkFakeGroup decls -- Rather clumsy; lots of unused fields
316 = HsGroup { hs_tyclds = decls, -- This is the one we want
317 hs_valds = [], hs_fords = [],
318 hs_instds = [], hs_fixds = [], hs_depds = [],
319 hs_ruleds = [], hs_defds = [] }
323 %************************************************************************
325 Type-checking the top level of a module
327 %************************************************************************
330 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
331 -- Returns the variables free in the decls
332 -- Reason: solely to report unused imports and bindings
334 = do { -- Load the hi-boot interface for this module, if any
335 -- We do this now so that the boot_names can be passed
336 -- to tcTyAndClassDecls, because the boot_names are
337 -- automatically considered to be loop breakers
338 boot_names <- loadHiBootInterface ;
340 -- Do all the declarations
341 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_names decls) ;
343 -- tcSimplifyTop deals with constant or ambiguous InstIds.
344 -- How could there be ambiguous ones? They can only arise if a
345 -- top-level decl falls under the monomorphism
346 -- restriction, and no subsequent decl instantiates its
347 -- type. (Usually, ambiguous type variables are resolved
348 -- during the generalisation step.)
349 traceTc (text "Tc8") ;
350 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
351 -- Setting the global env exposes the instances to tcSimplifyTop
352 -- Setting the local env exposes the local Ids to tcSimplifyTop,
353 -- so that we get better error messages (monomorphism restriction)
355 -- Backsubstitution. This must be done last.
356 -- Even tcSimplifyTop may do some unification.
357 traceTc (text "Tc9") ;
358 let { (tcg_env, _) = tc_envs ;
359 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
360 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
362 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
365 let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
367 -- Compre the hi-boot iface (if any) with the real thing
368 checkHiBootIface final_type_env boot_names ;
370 -- Make the new type env available to stuff slurped from interface files
371 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
373 return (tcg_env { tcg_type_env = final_type_env,
374 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' })
377 tc_rn_src_decls :: [Name] -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
378 -- Loops around dealing with each top level inter-splice group
379 -- in turn, until it's dealt with the entire module
380 tc_rn_src_decls boot_names ds
381 = do { let { (first_group, group_tail) = findSplice ds } ;
382 -- If ds is [] we get ([], Nothing)
384 -- Type check the decls up to, but not including, the first splice
385 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_names first_group ;
387 -- Bale out if errors; for example, error recovery when checking
388 -- the RHS of 'main' can mean that 'main' is not in the envt for
389 -- the subsequent checkMain test
394 -- If there is no splice, we're nearly done
396 Nothing -> do { -- Last thing: check for `main'
397 tcg_env <- checkMain ;
398 return (tcg_env, tcl_env)
401 -- If there's a splice, we must carry on
402 Just (SpliceDecl splice_expr, rest_ds) -> do {
404 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
407 -- Rename the splice expression, and get its supporting decls
408 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
409 failIfErrsM ; -- Don't typecheck if renaming failed
411 -- Execute the splice
412 spliced_decls <- tcSpliceDecls rn_splice_expr ;
414 -- Glue them on the front of the remaining decls and loop
415 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
416 tc_rn_src_decls boot_names (spliced_decls ++ rest_ds)
421 %************************************************************************
423 Comparing the hi-boot interface with the real thing
425 %************************************************************************
427 In both one-shot mode and GHCi mode, hi-boot interfaces are demand-loaded
428 into the External Package Table. Once we've typechecked the body of the
429 module, we want to compare what we've found (gathered in a TypeEnv) with
430 the hi-boot stuff in the EPT. We do so here, using the export list of
431 the hi-boot interface as our checklist.
434 checkHiBootIface :: TypeEnv -> [Name] -> TcM ()
435 -- Compare the hi-boot file for this module (if there is one)
436 -- with the type environment we've just come up with
437 -- In the common case where there is no hi-boot file, the list
438 -- of boot_names is empty.
439 checkHiBootIface env boot_names
440 = mapM_ (check_one env) boot_names
443 check_one local_env name
446 -- Look up the hi-boot one;
447 -- it should jolly well be there (else GHC bug)
448 ; case lookupTypeEnv (eps_PTE eps) name of {
449 Nothing -> pprPanic "checkHiBootIface" (ppr name) ;
452 -- Look it up in the local type env
453 -- It should be there, but it's a programmer error if not
454 case lookupTypeEnv local_env name of
455 Nothing -> addErrTc (missingBootThing boot_thing)
456 Just real_thing -> check_thing boot_thing real_thing
460 check_thing (ATyCon boot_tc) (ATyCon real_tc)
461 | isSynTyCon boot_tc && isSynTyCon real_tc,
462 defn1 `tcEqType` substTyWith tvs2 (mkTyVarTys tvs1) defn2
465 | tyConKind boot_tc == tyConKind real_tc
468 (tvs1, defn1) = getSynTyConDefn boot_tc
469 (tvs2, defn2) = getSynTyConDefn boot_tc
471 check_thing (AnId boot_id) (AnId real_id)
472 | idType boot_id `tcEqType` idType real_id
475 check_thing (ADataCon dc1) (ADataCon dc2)
476 | idType (dataConWrapId dc1) `tcEqType` idType (dataConWrapId dc2)
479 -- Can't declare a class in a hi-boot file
481 check_thing boot_thing real_thing -- Default case; failure
482 = addErrAt (srcLocSpan (getSrcLoc real_thing))
483 (bootMisMatch real_thing)
486 missingBootThing thing
487 = ppr thing <+> ptext SLIT("is defined in the hi-boot file, but not in the module")
489 = ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hi-boot file")
493 %************************************************************************
495 Type-checking the top level of a module
497 %************************************************************************
499 tcRnGroup takes a bunch of top-level source-code declarations, and
501 * gets supporting declarations from interface files
504 * and augments the TcGblEnv with the results
506 In Template Haskell it may be called repeatedly for each group of
507 declarations. It expects there to be an incoming TcGblEnv in the
508 monad; it augments it and returns the new TcGblEnv.
511 tcRnGroup :: [Name] -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
512 -- Returns the variables free in the decls, for unused-binding reporting
513 tcRnGroup boot_names decls
514 = do { -- Rename the declarations
515 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
516 setGblEnv tcg_env $ do {
518 -- Typecheck the declarations
519 tcTopSrcDecls boot_names rn_decls
522 ------------------------------------------------
523 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
525 = do { -- Bring top level binders into scope
526 (rdr_env, imports) <- importsFromLocalDecls group ;
527 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
528 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
531 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
532 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
534 -- Rename the source decls
535 (tcg_env, rn_decls) <- rnSrcDecls group ;
538 -- Dump trace of renaming part
539 rnDump (ppr rn_decls) ;
541 return (tcg_env, rn_decls)
544 ------------------------------------------------
545 tcTopSrcDecls :: [Name] -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
546 tcTopSrcDecls boot_names
547 (HsGroup { hs_tyclds = tycl_decls,
548 hs_instds = inst_decls,
549 hs_fords = foreign_decls,
550 hs_defds = default_decls,
551 hs_ruleds = rule_decls,
552 hs_valds = val_binds })
553 = do { -- Type-check the type and class decls, and all imported decls
554 -- The latter come in via tycl_decls
555 traceTc (text "Tc2") ;
557 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_names tycl_decls) ;
558 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
559 -- an error we'd better stop now, to avoid a cascade
561 -- Make these type and class decls available to stuff slurped from interface files
562 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
565 setGblEnv tcg_env $ do {
566 -- Source-language instances, including derivings,
567 -- and import the supporting declarations
568 traceTc (text "Tc3") ;
569 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
570 setGblEnv tcg_env $ do {
572 -- Foreign import declarations next. No zonking necessary
573 -- here; we can tuck them straight into the global environment.
574 traceTc (text "Tc4") ;
575 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
576 tcExtendGlobalValEnv fi_ids $ do {
578 -- Default declarations
579 traceTc (text "Tc4a") ;
580 default_tys <- tcDefaults default_decls ;
581 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
583 -- Value declarations next
584 -- We also typecheck any extra binds that came out
585 -- of the "deriving" process (deriv_binds)
586 traceTc (text "Tc5") ;
587 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
588 setLclTypeEnv lcl_env $ do {
590 -- Second pass over class and instance declarations,
591 traceTc (text "Tc6") ;
592 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
593 showLIE (text "after instDecls2") ;
596 -- They need to be zonked, so we return them
597 traceTc (text "Tc7") ;
598 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
601 rules <- tcRules rule_decls ;
604 traceTc (text "Tc7a") ;
605 tcg_env <- getGblEnv ;
606 let { all_binds = tc_val_binds `unionBags`
607 inst_binds `unionBags`
610 -- Extend the GblEnv with the (as yet un-zonked)
611 -- bindings, rules, foreign decls
612 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
613 tcg_rules = tcg_rules tcg_env ++ rules,
614 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
615 return (tcg_env', lcl_env)
620 %************************************************************************
624 %************************************************************************
628 = do { ghci_mode <- getGhciMode ;
629 tcg_env <- getGblEnv ;
631 mb_main_mod <- readMutVar v_MainModIs ;
632 mb_main_fn <- readMutVar v_MainFunIs ;
633 let { main_mod = case mb_main_mod of {
634 Just mod -> mkModule mod ;
636 main_fn = case mb_main_fn of {
637 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
638 Nothing -> main_RDR_Unqual } } ;
640 check_main ghci_mode tcg_env main_mod main_fn
644 check_main ghci_mode tcg_env main_mod main_fn
645 -- If we are in module Main, check that 'main' is defined.
646 -- It may be imported from another module!
649 -- Blimey: a whole page of code to do this...
654 = addErrCtxt mainCtxt $
655 do { mb_main <- lookupSrcOcc_maybe main_fn
656 -- Check that 'main' is in scope
657 -- It might be imported from another module!
659 Nothing -> do { complain_no_main
662 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
663 -- :Main.main :: IO () = runIO main
665 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
668 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
669 main_bind = noLoc (VarBind root_main_id main_expr) }
671 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
673 tcg_dus = tcg_dus tcg_env
674 `plusDU` usesOnly (unitFV main_name)
675 -- Record the use of 'main', so that we don't
676 -- complain about it being defined but not used
680 mod = tcg_mod tcg_env
682 complain_no_main | ghci_mode == Interactive = return ()
683 | otherwise = failWithTc noMainMsg
684 -- In interactive mode, don't worry about the absence of 'main'
685 -- In other modes, fail altogether, so that we don't go on
686 -- and complain a second time when processing the export list.
688 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
689 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
690 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
694 %*********************************************************
698 %*********************************************************
702 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
703 setInteractiveContext icxt thing_inside
704 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
705 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
706 tcg_type_env = ic_type_env icxt}) $
707 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
714 -> InteractiveContext
716 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
717 -- The returned [Name] is the same as the input except for
718 -- ExprStmt, in which case the returned [Name] is [itName]
720 -- The returned TypecheckedHsExpr is of type IO [ () ],
721 -- a list of the bound values, coerced to ().
723 tcRnStmt hsc_env ictxt rdr_stmt
724 = initTcPrintErrors hsc_env iNTERACTIVE $
725 setInteractiveContext ictxt $ do {
727 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
728 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
729 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
732 -- The real work is done here
733 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
735 traceTc (text "tcs 1") ;
736 let { -- (a) Make all the bound ids "global" ids, now that
737 -- they're notionally top-level bindings. This is
738 -- important: otherwise when we come to compile an expression
739 -- using these ids later, the byte code generator will consider
740 -- the occurrences to be free rather than global.
742 -- (b) Tidy their types; this is important, because :info may
743 -- ask to look at them, and :info expects the things it looks
744 -- up to have tidy types
745 global_ids = map globaliseAndTidy bound_ids ;
747 -- Update the interactive context
748 rn_env = ic_rn_local_env ictxt ;
749 type_env = ic_type_env ictxt ;
751 bound_names = map idName global_ids ;
752 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
754 -- Remove any shadowed bindings from the type_env;
755 -- they are inaccessible but might, I suppose, cause
756 -- a space leak if we leave them there
757 shadowed = [ n | name <- bound_names,
758 let rdr_name = mkRdrUnqual (nameOccName name),
759 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
761 filtered_type_env = delListFromNameEnv type_env shadowed ;
762 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
764 new_ic = ictxt { ic_rn_local_env = new_rn_env,
765 ic_type_env = new_type_env }
768 dumpOptTcRn Opt_D_dump_tc
769 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
770 text "Typechecked expr" <+> ppr tc_expr]) ;
772 returnM (new_ic, bound_names, tc_expr)
775 globaliseAndTidy :: Id -> Id
777 -- Give the Id a Global Name, and tidy its type
778 = setIdType (globaliseId VanillaGlobal id) tidy_type
780 tidy_type = tidyTopType (idType id)
783 Here is the grand plan, implemented in tcUserStmt
785 What you type The IO [HValue] that hscStmt returns
786 ------------- ------------------------------------
787 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
790 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
793 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
794 [NB: result not printed] bindings: [it]
796 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
797 result showable) bindings: [it]
799 expr (of non-IO type,
800 result not showable) ==> error
804 ---------------------------
805 tcUserStmt :: LStmt Name -> TcM ([Id], LHsExpr Id)
806 tcUserStmt (L _ (ExprStmt expr _))
807 = newUnique `thenM` \ uniq ->
809 fresh_it = itName uniq
810 the_bind = noLoc $ FunBind (noLoc fresh_it) False
811 (mkMatchGroup [mkSimpleMatch [] expr])
813 tryTcLIE_ (do { -- Try this if the other fails
814 traceTc (text "tcs 1b") ;
816 nlLetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive],
817 nlExprStmt (nlHsApp (nlHsVar printName)
820 (do { -- Try this first
821 traceTc (text "tcs 1a") ;
822 tc_stmts [nlBindStmt (nlVarPat fresh_it) expr] })
824 tcUserStmt stmt = tc_stmts [stmt]
826 ---------------------------
828 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
830 ret_ty = mkListTy unitTy ;
831 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
833 names = map unLoc (collectStmtsBinders stmts) ;
835 stmt_ctxt = SC { sc_what = DoExpr,
837 sc_body = check_body,
840 infer_rhs rhs = do { (rhs', rhs_ty) <- tcInferRho rhs
841 ; [pat_ty] <- unifyTyConApp ioTyCon rhs_ty
842 ; return (rhs', pat_ty) } ;
843 check_body body = tcCheckRho body io_ret_ty ;
845 -- mk_return builds the expression
846 -- returnIO @ [()] [coerce () x, .., coerce () z]
848 -- Despite the inconvenience of building the type applications etc,
849 -- this *has* to be done in type-annotated post-typecheck form
850 -- because we are going to return a list of *polymorphic* values
851 -- coerced to type (). If we built a *source* stmt
852 -- return [coerce x, ..., coerce z]
853 -- then the type checker would instantiate x..z, and we wouldn't
854 -- get their *polymorphic* values. (And we'd get ambiguity errs
855 -- if they were overloaded, since they aren't applied to anything.)
856 mk_return ret_id ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
857 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
858 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
861 io_ty = mkTyConApp ioTyCon []
864 -- OK, we're ready to typecheck the stmts
865 traceTc (text "tcs 2") ;
866 ((ids, tc_expr), lie) <- getLIE $ do {
867 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
869 -- Look up the names right in the middle,
870 -- where they will all be in scope
871 ids <- mappM tcLookupId names ;
872 ret_id <- tcLookupId returnIOName ; -- return @ IO
873 return (ids, [nlResultStmt (mk_return ret_id ids)]) } ;
875 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
876 return (ids, noLoc (HsDo DoExpr tc_stmts io_ids io_ret_ty))
879 -- Simplify the context right here, so that we fail
880 -- if there aren't enough instances. Notably, when we see
882 -- we use recoverTc_ to try it <- e
883 -- and then let it = e
884 -- It's the simplify step that rejects the first.
885 traceTc (text "tcs 3") ;
886 const_binds <- tcSimplifyInteractive lie ;
888 -- Build result expression and zonk it
889 let { expr = mkHsLet const_binds tc_expr } ;
890 zonked_expr <- zonkTopLExpr expr ;
891 zonked_ids <- zonkTopBndrs ids ;
893 -- None of the Ids should be of unboxed type, because we
894 -- cast them all to HValues in the end!
895 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
897 return (zonked_ids, zonked_expr)
900 combine stmt (ids, stmts) = (ids, stmt:stmts)
901 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
902 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
906 tcRnExpr just finds the type of an expression
910 -> InteractiveContext
913 tcRnExpr hsc_env ictxt rdr_expr
914 = initTcPrintErrors hsc_env iNTERACTIVE $
915 setInteractiveContext ictxt $ do {
917 (rn_expr, fvs) <- rnLExpr rdr_expr ;
920 -- Now typecheck the expression;
921 -- it might have a rank-2 type (e.g. :t runST)
922 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
923 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
924 tcSimplifyInteractive lie_top ;
925 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
927 let { all_expr_ty = mkForAllTys qtvs' $
928 mkFunTys (map idType dict_ids) $
930 zonkTcType all_expr_ty
933 smpl_doc = ptext SLIT("main expression")
936 tcRnType just finds the kind of a type
940 -> InteractiveContext
943 tcRnType hsc_env ictxt rdr_type
944 = initTcPrintErrors hsc_env iNTERACTIVE $
945 setInteractiveContext ictxt $ do {
947 rn_type <- rnLHsType doc rdr_type ;
950 -- Now kind-check the type
951 (ty', kind) <- kcHsType rn_type ;
955 doc = ptext SLIT("In GHCi input")
961 %************************************************************************
963 More GHCi stuff, to do with browsing and getting info
965 %************************************************************************
969 mkExportEnv :: HscEnv -> [Module] -- Expose these modules' exports only
971 mkExportEnv hsc_env exports
972 = do { mb_envs <- initTcPrintErrors hsc_env iNTERACTIVE $
973 mappM getModuleExports exports
975 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
976 Nothing -> return emptyGlobalRdrEnv
977 -- Some error; initTc will have printed it
980 getModuleExports :: Module -> TcM GlobalRdrEnv
982 = do { iface <- load_iface mod
983 ; loadOrphanModules (dep_orphs (mi_deps iface))
984 -- Load any orphan-module interfaces,
985 -- so their instances are visible
986 ; names <- exportsToAvails (mi_exports iface)
987 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
988 | name <- nameSetToList names ] }
989 ; returnM (mkGlobalRdrEnv gres) }
991 vanillaProv :: Module -> Provenance
992 -- We're building a GlobalRdrEnv as if the user imported
993 -- all the specified modules into the global interactive module
994 vanillaProv mod = Imported [ImportSpec mod mod False
995 (srcLocSpan interactiveSrcLoc)] False
1001 -> InteractiveContext
1002 -> Module -- Module to inspect
1003 -> Bool -- Grab just the exports, or the whole toplev
1004 -> IO (Maybe [IfaceDecl])
1006 getModuleContents hsc_env ictxt mod exports_only
1007 = initTcPrintErrors hsc_env iNTERACTIVE (get_mod_contents exports_only)
1009 get_mod_contents exports_only
1010 | not exports_only -- We want the whole top-level type env
1011 -- so it had better be a home module
1012 = do { hpt <- getHpt
1013 ; case lookupModuleEnv hpt mod of
1014 Just mod_info -> return (map toIfaceDecl $
1017 md_types (hm_details mod_info))
1018 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
1019 -- This is a system error; the module should be in the HPT
1022 | otherwise -- Want the exports only
1023 = do { iface <- load_iface mod
1024 ; mappM get_decl [ (mod,avail) | (mod, avails) <- mi_exports iface
1028 get_decl (mod, avail)
1029 = do { main_name <- lookupOrig mod (availName avail)
1030 ; thing <- tcLookupGlobal main_name
1031 ; return (filter_decl (availNames avail) (toIfaceDecl thing)) }
1033 ---------------------
1034 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
1035 = decl { ifSigs = filter (keep_sig occs) sigs }
1036 filter_decl occs decl@(IfaceData {ifCons = IfDataTyCon th cons})
1037 = decl { ifCons = IfDataTyCon th (filter (keep_con occs) cons) }
1038 filter_decl occs decl@(IfaceData {ifCons = IfNewTyCon con})
1039 | keep_con occs con = decl
1040 | otherwise = decl {ifCons = IfAbstractTyCon} -- Hmm?
1041 filter_decl occs decl
1044 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
1045 keep_con occs con = ifConOcc con `elem` occs
1047 wantToSee (AnId id) = not (isImplicitId id)
1048 wantToSee (ADataCon _) = False -- They'll come via their TyCon
1051 ---------------------
1052 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
1054 doc = ptext SLIT("context for compiling statements")
1056 ---------------------
1057 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1058 <+> quotes (ppr mod)
1062 tcRnGetInfo :: HscEnv
1063 -> InteractiveContext
1065 -> IO (Maybe [(IfaceDecl,
1067 [(IfaceInst, SrcLoc)])])
1068 -- Used to implemnent :info in GHCi
1070 -- Look up a RdrName and return all the TyThings it might be
1071 -- A capitalised RdrName is given to us in the DataName namespace,
1072 -- but we want to treat it as *both* a data constructor
1073 -- *and* as a type or class constructor;
1074 -- hence the call to dataTcOccs, and we return up to two results
1075 tcRnGetInfo hsc_env ictxt rdr_name
1076 = initTcPrintErrors hsc_env iNTERACTIVE $
1077 setInteractiveContext ictxt $ do {
1079 -- If the identifier is a constructor (begins with an
1080 -- upper-case letter), then we need to consider both
1081 -- constructor and type class identifiers.
1082 let { rdr_names = dataTcOccs rdr_name } ;
1084 -- results :: [(Messages, Maybe Name)]
1085 results <- mapM (tryTc . lookupOccRn) rdr_names ;
1087 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1088 -- The successful lookups will be (Just name)
1089 let { (warns_s, good_names) = unzip [ (msgs, name)
1090 | (msgs, Just name) <- results] ;
1091 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1093 -- Fail if nothing good happened, else add warnings
1094 if null good_names then
1095 -- No lookup succeeded, so
1096 -- pick the first error message and report it
1097 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1098 -- while the other is "X is not in scope",
1099 -- we definitely want the former; but we might pick the latter
1100 do { addMessages (head errs_s) ; failM }
1101 else -- Add deprecation warnings
1102 mapM_ addMessages warns_s ;
1104 -- And lookup up the entities, avoiding duplicates, which arise
1105 -- because constructors and record selectors are represented by
1106 -- their parent declaration
1107 let { do_one name = do { thing <- tcLookupGlobal name
1108 ; let decl = toIfaceDecl thing
1109 ; fixity <- lookupFixityRn name
1110 ; insts <- lookupInsts thing
1111 ; return (decl, fixity, getSrcLoc thing,
1112 map mk_inst insts) } ;
1113 -- For the SrcLoc, the 'thing' has better info than
1114 -- the 'name' because getting the former forced the
1115 -- declaration to be loaded into the cache
1116 mk_inst dfun = (dfunToIfaceInst dfun, getSrcLoc dfun) ;
1117 cmp (d1,_,_,_) (d2,_,_,_) = ifName d1 `compare` ifName d2 } ;
1118 results <- mapM do_one good_names ;
1119 return (fst (removeDups cmp results))
1122 lookupInsts :: TyThing -> TcM [DFunId]
1123 lookupInsts (AClass cls)
1124 = do { loadImportedInsts cls [] -- [] means load all instances for cls
1125 ; inst_envs <- tcGetInstEnvs
1126 ; return [df | (_,_,df) <- classInstances inst_envs cls] }
1128 lookupInsts (ATyCon tc)
1129 = do { eps <- getEps -- Load all instances for all classes that are
1130 -- in the type environment (which are all the ones
1131 -- we've seen in any interface file so far
1132 ; mapM_ (\c -> loadImportedInsts c [])
1133 (typeEnvClasses (eps_PTE eps))
1134 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1135 ; return (get home_ie ++ get pkg_ie) }
1137 get ie = [df | (_,_,df) <- instEnvElts ie, relevant df]
1138 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1139 tc_name = tyConName tc
1141 lookupInsts other = return []
1144 toIfaceDecl :: TyThing -> IfaceDecl
1146 = tyThingToIfaceDecl True -- Discard IdInfo
1147 emptyNameSet -- Show data cons
1148 ext_nm (munge thing)
1150 ext_nm n = ExtPkg (nameModule n) (nameOccName n)
1152 -- munge transforms a thing to it's "parent" thing
1153 munge (ADataCon dc) = ATyCon (dataConTyCon dc)
1154 munge (AnId id) = case globalIdDetails id of
1155 RecordSelId tc lbl -> ATyCon tc
1156 ClassOpId cls -> AClass cls
1158 munge other_thing = other_thing
1163 %************************************************************************
1167 %************************************************************************
1170 rnDump :: SDoc -> TcRn ()
1171 -- Dump, with a banner, if -ddump-rn
1172 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1174 tcDump :: TcGblEnv -> TcRn ()
1176 = do { dflags <- getDOpts ;
1178 -- Dump short output if -ddump-types or -ddump-tc
1179 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1180 (dumpTcRn short_dump) ;
1182 -- Dump bindings if -ddump-tc
1183 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1186 short_dump = pprTcGblEnv env
1187 full_dump = pprLHsBinds (tcg_binds env)
1188 -- NB: foreign x-d's have undefined's in their types;
1189 -- hence can't show the tc_fords
1192 = do { dflags <- getDOpts ;
1193 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1194 (dumpTcRn (pprModGuts mod_guts)) ;
1196 -- Dump bindings if -ddump-tc
1197 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1199 full_dump = pprCoreBindings (mg_binds mod_guts)
1201 -- It's unpleasant having both pprModGuts and pprModDetails here
1202 pprTcGblEnv :: TcGblEnv -> SDoc
1203 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1204 tcg_insts = dfun_ids,
1206 tcg_imports = imports })
1207 = vcat [ ppr_types dfun_ids type_env
1208 , ppr_insts dfun_ids
1209 , vcat (map ppr rules)
1210 , ppr_gen_tycons (typeEnvTyCons type_env)
1211 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1212 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1214 pprModGuts :: ModGuts -> SDoc
1215 pprModGuts (ModGuts { mg_types = type_env,
1217 = vcat [ ppr_types [] type_env,
1221 ppr_types :: [Var] -> TypeEnv -> SDoc
1222 ppr_types dfun_ids type_env
1223 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1225 ids = [id | id <- typeEnvIds type_env, want_sig id]
1226 want_sig id | opt_PprStyle_Debug = True
1227 | otherwise = isLocalId id &&
1228 isExternalName (idName id) &&
1229 not (id `elem` dfun_ids)
1230 -- isLocalId ignores data constructors, records selectors etc.
1231 -- The isExternalName ignores local dictionary and method bindings
1232 -- that the type checker has invented. Top-level user-defined things
1233 -- have External names.
1235 ppr_insts :: [Var] -> SDoc
1236 ppr_insts [] = empty
1237 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1239 ppr_sigs :: [Var] -> SDoc
1241 -- Print type signatures; sort by OccName
1242 = vcat (map ppr_sig (sortLe le_sig ids))
1244 le_sig id1 id2 = getOccName id1 <= getOccName id2
1245 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1247 ppr_rules :: [IdCoreRule] -> SDoc
1248 ppr_rules [] = empty
1249 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1250 nest 4 (pprIdRules rs),
1253 ppr_gen_tycons [] = empty
1254 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1255 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]