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 InstEnv ( extendInstEnvList )
41 import TcBinds ( tcTopBinds )
42 import TcDefaults ( tcDefaults )
43 import TcEnv ( tcExtendGlobalValEnv )
44 import TcRules ( tcRules )
45 import TcForeign ( tcForeignImports, tcForeignExports )
46 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
47 import TcIface ( tcExtCoreBindings )
48 import TcSimplify ( tcSimplifyTop )
49 import TcTyClsDecls ( tcTyAndClassDecls )
50 import LoadIface ( loadOrphanModules, loadHiBootInterface )
51 import RnNames ( importsFromLocalDecls, rnImports, exportsFromAvail,
52 reportUnusedNames, reportDeprecations )
53 import RnEnv ( lookupSrcOcc_maybe )
54 import RnSource ( rnSrcDecls, rnTyClDecls, checkModDeprec )
55 import PprCore ( pprIdRules, pprCoreBindings )
56 import CoreSyn ( IdCoreRule, bindersOfBinds )
57 import DataCon ( dataConWrapId )
58 import ErrUtils ( Messages, mkDumpDoc, showPass )
59 import Id ( mkExportedLocalId, isLocalId, idName, idType )
61 import Module ( Module, ModuleEnv, mkModule, moduleEnvElts )
62 import OccName ( mkVarOcc )
63 import Name ( Name, isExternalName, getSrcLoc, getOccName )
65 import TyCon ( tyConHasGenerics, isSynTyCon, getSynTyConDefn, tyConKind )
66 import SrcLoc ( srcLocSpan, Located(..), noLoc )
68 import HscTypes ( ModGuts(..), HscEnv(..), ExternalPackageState(..),
69 GhciMode(..), IsBootInterface, noDependencies,
70 Deprecs( NoDeprecs ), plusDeprecs,
71 ForeignStubs(NoStubs), TyThing(..),
72 TypeEnv, lookupTypeEnv, hptInstances,
73 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
77 import HsSyn ( HsStmtContext(..), Stmt(..), HsExpr(..), HsBindGroup(..),
78 LStmt, LHsExpr, LHsType, mkMatchGroup,
79 collectStmtsBinders, mkSimpleMatch,
80 nlLetStmt, nlExprStmt, nlBindStmt, nlResultStmt, nlVarPat )
81 import RdrName ( GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
82 Provenance(..), ImportSpec(..),
83 lookupLocalRdrEnv, extendLocalRdrEnv )
84 import RnSource ( addTcgDUs )
85 import TcHsSyn ( mkHsLet, zonkTopLExpr, zonkTopBndrs )
86 import TcHsType ( kcHsType )
87 import TcExpr ( tcCheckRho )
88 import TcIface ( loadImportedInsts )
89 import TcMType ( zonkTcType, zonkQuantifiedTyVar )
90 import TcUnify ( unifyTyConApp )
91 import TcMatches ( tcStmtsAndThen, TcStmtCtxt(..) )
92 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
93 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType,
94 isUnLiftedType, tyClsNamesOfDFunHead )
95 import TcEnv ( tcLookupTyCon, tcLookupId, tcLookupGlobal )
96 import RnTypes ( rnLHsType )
97 import Inst ( tcStdSyntaxName, tcGetInstEnvs )
98 import InstEnv ( DFunId, classInstances, instEnvElts )
99 import RnExpr ( rnStmts, rnLExpr )
100 import RnNames ( exportsToAvails )
101 import LoadIface ( loadSrcInterface )
102 import IfaceSyn ( IfaceDecl(..), IfaceClassOp(..), IfaceConDecl(..),
103 IfaceExtName(..), IfaceConDecls(..), IfaceInst(..),
104 tyThingToIfaceDecl, dfunToIfaceInst )
105 import IfaceEnv ( lookupOrig )
106 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
107 import Id ( Id, isImplicitId, setIdType, globalIdDetails )
108 import MkId ( unsafeCoerceId )
109 import DataCon ( dataConTyCon )
110 import TyCon ( tyConName )
111 import TysWiredIn ( mkListTy, unitTy )
112 import IdInfo ( GlobalIdDetails(..) )
113 import SrcLoc ( interactiveSrcLoc, unLoc )
115 import Var ( globaliseId )
116 import Name ( nameOccName, nameModule )
117 import NameEnv ( delListFromNameEnv )
118 import PrelNames ( iNTERACTIVE, ioTyConName, printName, monadNames, itName, returnIOName )
119 import Module ( Module, lookupModuleEnv )
120 import HscTypes ( InteractiveContext(..), HomeModInfo(..), typeEnvElts, typeEnvClasses,
121 availNames, availName, ModIface(..),
122 ModDetails(..), Dependencies(..) )
123 import BasicTypes ( RecFlag(..), Fixity )
124 import Bag ( unitBag )
125 import ListSetOps ( removeDups )
126 import Panic ( ghcError, GhcException(..) )
127 import SrcLoc ( SrcLoc )
130 import FastString ( mkFastString )
131 import Util ( sortLe )
132 import Bag ( unionBags, snocBag )
134 import Maybe ( isJust )
139 %************************************************************************
141 Typecheck and rename a module
143 %************************************************************************
148 -> Located (HsModule RdrName)
149 -> IO (Messages, Maybe TcGblEnv)
151 tcRnModule hsc_env (L loc (HsModule maybe_mod export_ies
152 import_decls local_decls mod_deprec))
153 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
155 let { this_mod = case maybe_mod of
157 -- 'module M where' is omitted
158 Just (L _ mod) -> mod } ;
161 initTc hsc_env this_mod $
164 checkForPackageModule (hsc_dflags hsc_env) this_mod;
166 -- Deal with imports; sets tcg_rdr_env, tcg_imports
167 (rdr_env, imports) <- rnImports import_decls ;
169 -- Record boot-file info in the EPS, so that it's
170 -- visible to loadHiBootInterface in tcRnSrcDecls,
171 -- and any other incrementally-performed imports
172 let { dep_mods :: ModuleEnv (Module, IsBootInterface)
173 ; dep_mods = imp_dep_mods imports } ;
175 updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ;
177 -- Update the gbl env
178 let { home_insts = hptInstances hsc_env (moduleEnvElts dep_mods) } ;
180 gbl { tcg_rdr_env = rdr_env,
181 tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts,
182 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
185 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
186 -- Fail if there are any errors so far
187 -- The error printing (if needed) takes advantage
188 -- of the tcg_env we have now set
191 -- Load any orphan-module interfaces, so that
192 -- their rules and instance decls will be found
193 loadOrphanModules (imp_orphs imports) ;
195 traceRn (text "rn1a") ;
196 -- Rename and type check the declarations
197 tcg_env <- tcRnSrcDecls local_decls ;
198 setGblEnv tcg_env $ do {
200 traceRn (text "rn3") ;
202 -- Report the use of any deprecated things
203 -- We do this before processsing the export list so
204 -- that we don't bleat about re-exporting a deprecated
205 -- thing (especially via 'module Foo' export item)
206 -- Only uses in the body of the module are complained about
207 reportDeprecations tcg_env ;
209 -- Process the export list
210 exports <- exportsFromAvail (isJust maybe_mod) export_ies ;
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
232 -- This is really a sanity check that the user has given -package-name
233 -- if necessary. -package-name is only necessary when the package database
234 -- already contains the current package, because then we can't tell
235 -- whether a given module is in the current package or not, without knowing
236 -- the name of the current package.
237 checkForPackageModule dflags this_mod
238 | not (isHomeModule dflags this_mod),
239 Just (pkg,_) <- moduleToPackageConfig dflags this_mod =
241 ppr_pkg = ppr (mkPackageId (package pkg))
243 addErr (ptext SLIT("Module") <+> quotes (ppr this_mod) <+>
244 ptext SLIT("is a member of package") <+> ppr_pkg <> char '.' $$
245 ptext SLIT("To compile this module, please use -ignore-package") <+> ppr_pkg <> char '.')
246 | otherwise = return ()
250 %************************************************************************
252 Type-checking external-core modules
254 %************************************************************************
257 tcRnExtCore :: HscEnv
259 -> IO (Messages, Maybe ModGuts)
260 -- Nothing => some error occurred
262 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
263 -- The decls are IfaceDecls; all names are original names
264 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
266 initTc hsc_env this_mod $ do {
268 let { ldecls = map noLoc decls } ;
270 -- Deal with the type declarations; first bring their stuff
271 -- into scope, then rname them, then type check them
272 (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup ldecls) ;
274 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
275 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
278 rn_decls <- rnTyClDecls ldecls ;
281 -- Dump trace of renaming part
282 rnDump (ppr rn_decls) ;
284 -- Typecheck them all together so that
285 -- any mutually recursive types are done right
286 tcg_env <- checkNoErrs (tcTyAndClassDecls [{- no boot names -}] rn_decls) ;
287 -- Make the new type env available to stuff slurped from interface files
289 setGblEnv tcg_env $ do {
291 -- Now the core bindings
292 core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ;
296 bndrs = bindersOfBinds core_binds ;
297 my_exports = mkNameSet (map idName bndrs) ;
298 -- ToDo: export the data types also?
300 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
302 mod_guts = ModGuts { mg_module = this_mod,
303 mg_usages = [], -- ToDo: compute usage
304 mg_dir_imps = [], -- ??
305 mg_deps = noDependencies, -- ??
306 mg_exports = my_exports,
307 mg_types = final_type_env,
308 mg_insts = tcg_insts tcg_env,
310 mg_binds = core_binds,
313 mg_rdr_env = emptyGlobalRdrEnv,
314 mg_fix_env = emptyFixityEnv,
315 mg_deprecs = NoDeprecs,
319 tcCoreDump mod_guts ;
324 mkFakeGroup decls -- Rather clumsy; lots of unused fields
325 = HsGroup { hs_tyclds = decls, -- This is the one we want
326 hs_valds = [], hs_fords = [],
327 hs_instds = [], hs_fixds = [], hs_depds = [],
328 hs_ruleds = [], hs_defds = [] }
332 %************************************************************************
334 Type-checking the top level of a module
336 %************************************************************************
339 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
340 -- Returns the variables free in the decls
341 -- Reason: solely to report unused imports and bindings
343 = do { -- Load the hi-boot interface for this module, if any
344 -- We do this now so that the boot_names can be passed
345 -- to tcTyAndClassDecls, because the boot_names are
346 -- automatically considered to be loop breakers
347 boot_names <- loadHiBootInterface ;
349 -- Do all the declarations
350 (tc_envs, lie) <- getLIE (tc_rn_src_decls boot_names decls) ;
352 -- tcSimplifyTop deals with constant or ambiguous InstIds.
353 -- How could there be ambiguous ones? They can only arise if a
354 -- top-level decl falls under the monomorphism
355 -- restriction, and no subsequent decl instantiates its
356 -- type. (Usually, ambiguous type variables are resolved
357 -- during the generalisation step.)
358 traceTc (text "Tc8") ;
359 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
360 -- Setting the global env exposes the instances to tcSimplifyTop
361 -- Setting the local env exposes the local Ids to tcSimplifyTop,
362 -- so that we get better error messages (monomorphism restriction)
364 -- Backsubstitution. This must be done last.
365 -- Even tcSimplifyTop may do some unification.
366 traceTc (text "Tc9") ;
367 let { (tcg_env, _) = tc_envs ;
368 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
369 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
371 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
374 let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
376 -- Compre the hi-boot iface (if any) with the real thing
377 checkHiBootIface final_type_env boot_names ;
379 -- Make the new type env available to stuff slurped from interface files
380 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
382 return (tcg_env { tcg_type_env = final_type_env,
383 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' })
386 tc_rn_src_decls :: [Name] -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
387 -- Loops around dealing with each top level inter-splice group
388 -- in turn, until it's dealt with the entire module
389 tc_rn_src_decls boot_names ds
390 = do { let { (first_group, group_tail) = findSplice ds } ;
391 -- If ds is [] we get ([], Nothing)
393 -- Type check the decls up to, but not including, the first splice
394 tc_envs@(tcg_env,tcl_env) <- tcRnGroup boot_names first_group ;
396 -- Bale out if errors; for example, error recovery when checking
397 -- the RHS of 'main' can mean that 'main' is not in the envt for
398 -- the subsequent checkMain test
403 -- If there is no splice, we're nearly done
405 Nothing -> do { -- Last thing: check for `main'
406 tcg_env <- checkMain ;
407 return (tcg_env, tcl_env)
410 -- If there's a splice, we must carry on
411 Just (SpliceDecl splice_expr, rest_ds) -> do {
413 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
416 -- Rename the splice expression, and get its supporting decls
417 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
418 failIfErrsM ; -- Don't typecheck if renaming failed
420 -- Execute the splice
421 spliced_decls <- tcSpliceDecls rn_splice_expr ;
423 -- Glue them on the front of the remaining decls and loop
424 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
425 tc_rn_src_decls boot_names (spliced_decls ++ rest_ds)
430 %************************************************************************
432 Comparing the hi-boot interface with the real thing
434 %************************************************************************
436 In both one-shot mode and GHCi mode, hi-boot interfaces are demand-loaded
437 into the External Package Table. Once we've typechecked the body of the
438 module, we want to compare what we've found (gathered in a TypeEnv) with
439 the hi-boot stuff in the EPT. We do so here, using the export list of
440 the hi-boot interface as our checklist.
443 checkHiBootIface :: TypeEnv -> [Name] -> TcM ()
444 -- Compare the hi-boot file for this module (if there is one)
445 -- with the type environment we've just come up with
446 -- In the common case where there is no hi-boot file, the list
447 -- of boot_names is empty.
448 checkHiBootIface env boot_names
449 = mapM_ (check_one env) boot_names
452 check_one local_env name
455 -- Look up the hi-boot one;
456 -- it should jolly well be there (else GHC bug)
457 ; case lookupTypeEnv (eps_PTE eps) name of {
458 Nothing -> pprPanic "checkHiBootIface" (ppr name) ;
461 -- Look it up in the local type env
462 -- It should be there, but it's a programmer error if not
463 case lookupTypeEnv local_env name of
464 Nothing -> addErrTc (missingBootThing boot_thing)
465 Just real_thing -> check_thing boot_thing real_thing
469 check_thing (ATyCon boot_tc) (ATyCon real_tc)
470 | isSynTyCon boot_tc && isSynTyCon real_tc,
471 defn1 `tcEqType` substTyWith tvs2 (mkTyVarTys tvs1) defn2
474 | tyConKind boot_tc == tyConKind real_tc
477 (tvs1, defn1) = getSynTyConDefn boot_tc
478 (tvs2, defn2) = getSynTyConDefn boot_tc
480 check_thing (AnId boot_id) (AnId real_id)
481 | idType boot_id `tcEqType` idType real_id
484 check_thing (ADataCon dc1) (ADataCon dc2)
485 | idType (dataConWrapId dc1) `tcEqType` idType (dataConWrapId dc2)
488 -- Can't declare a class in a hi-boot file
490 check_thing boot_thing real_thing -- Default case; failure
491 = addErrAt (srcLocSpan (getSrcLoc real_thing))
492 (bootMisMatch real_thing)
495 missingBootThing thing
496 = ppr thing <+> ptext SLIT("is defined in the hi-boot file, but not in the module")
498 = ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hi-boot file")
502 %************************************************************************
504 Type-checking the top level of a module
506 %************************************************************************
508 tcRnGroup takes a bunch of top-level source-code declarations, and
510 * gets supporting declarations from interface files
513 * and augments the TcGblEnv with the results
515 In Template Haskell it may be called repeatedly for each group of
516 declarations. It expects there to be an incoming TcGblEnv in the
517 monad; it augments it and returns the new TcGblEnv.
520 tcRnGroup :: [Name] -> HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
521 -- Returns the variables free in the decls, for unused-binding reporting
522 tcRnGroup boot_names decls
523 = do { -- Rename the declarations
524 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
525 setGblEnv tcg_env $ do {
527 -- Typecheck the declarations
528 tcTopSrcDecls boot_names rn_decls
531 ------------------------------------------------
532 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
534 = do { -- Bring top level binders into scope
535 (rdr_env, imports) <- importsFromLocalDecls group ;
536 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
537 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
540 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
541 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
543 -- Rename the source decls
544 (tcg_env, rn_decls) <- rnSrcDecls group ;
547 -- Dump trace of renaming part
548 rnDump (ppr rn_decls) ;
550 return (tcg_env, rn_decls)
553 ------------------------------------------------
554 tcTopSrcDecls :: [Name] -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
555 tcTopSrcDecls boot_names
556 (HsGroup { hs_tyclds = tycl_decls,
557 hs_instds = inst_decls,
558 hs_fords = foreign_decls,
559 hs_defds = default_decls,
560 hs_ruleds = rule_decls,
561 hs_valds = val_binds })
562 = do { -- Type-check the type and class decls, and all imported decls
563 -- The latter come in via tycl_decls
564 traceTc (text "Tc2") ;
566 tcg_env <- checkNoErrs (tcTyAndClassDecls boot_names tycl_decls) ;
567 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
568 -- an error we'd better stop now, to avoid a cascade
570 -- Make these type and class decls available to stuff slurped from interface files
571 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
574 setGblEnv tcg_env $ do {
575 -- Source-language instances, including derivings,
576 -- and import the supporting declarations
577 traceTc (text "Tc3") ;
578 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
579 setGblEnv tcg_env $ do {
581 -- Foreign import declarations next. No zonking necessary
582 -- here; we can tuck them straight into the global environment.
583 traceTc (text "Tc4") ;
584 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
585 tcExtendGlobalValEnv fi_ids $ do {
587 -- Default declarations
588 traceTc (text "Tc4a") ;
589 default_tys <- tcDefaults default_decls ;
590 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
592 -- Value declarations next
593 -- We also typecheck any extra binds that came out
594 -- of the "deriving" process (deriv_binds)
595 traceTc (text "Tc5") ;
596 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
597 setLclTypeEnv lcl_env $ do {
599 -- Second pass over class and instance declarations,
600 traceTc (text "Tc6") ;
601 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
602 showLIE (text "after instDecls2") ;
605 -- They need to be zonked, so we return them
606 traceTc (text "Tc7") ;
607 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
610 rules <- tcRules rule_decls ;
613 traceTc (text "Tc7a") ;
614 tcg_env <- getGblEnv ;
615 let { all_binds = tc_val_binds `unionBags`
616 inst_binds `unionBags`
619 -- Extend the GblEnv with the (as yet un-zonked)
620 -- bindings, rules, foreign decls
621 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
622 tcg_rules = tcg_rules tcg_env ++ rules,
623 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
624 return (tcg_env', lcl_env)
629 %************************************************************************
633 %************************************************************************
637 = do { ghci_mode <- getGhciMode ;
638 tcg_env <- getGblEnv ;
640 mb_main_mod <- readMutVar v_MainModIs ;
641 mb_main_fn <- readMutVar v_MainFunIs ;
642 let { main_mod = case mb_main_mod of {
643 Just mod -> mkModule mod ;
645 main_fn = case mb_main_fn of {
646 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
647 Nothing -> main_RDR_Unqual } } ;
649 check_main ghci_mode tcg_env main_mod main_fn
653 check_main ghci_mode tcg_env main_mod main_fn
654 -- If we are in module Main, check that 'main' is defined.
655 -- It may be imported from another module!
658 -- Blimey: a whole page of code to do this...
663 = addErrCtxt mainCtxt $
664 do { mb_main <- lookupSrcOcc_maybe main_fn
665 -- Check that 'main' is in scope
666 -- It might be imported from another module!
668 Nothing -> do { complain_no_main
671 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
672 -- :Main.main :: IO () = runIO main
674 ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $
677 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
678 main_bind = noLoc (VarBind root_main_id main_expr) }
680 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
682 tcg_dus = tcg_dus tcg_env
683 `plusDU` usesOnly (unitFV main_name)
684 -- Record the use of 'main', so that we don't
685 -- complain about it being defined but not used
689 mod = tcg_mod tcg_env
691 complain_no_main | ghci_mode == Interactive = return ()
692 | otherwise = failWithTc noMainMsg
693 -- In interactive mode, don't worry about the absence of 'main'
694 -- In other modes, fail altogether, so that we don't go on
695 -- and complain a second time when processing the export list.
697 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
698 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
699 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
703 %*********************************************************
707 %*********************************************************
711 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
712 setInteractiveContext icxt thing_inside
713 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
714 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
715 tcg_type_env = ic_type_env icxt}) $
716 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
723 -> InteractiveContext
725 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
726 -- The returned [Name] is the same as the input except for
727 -- ExprStmt, in which case the returned [Name] is [itName]
729 -- The returned TypecheckedHsExpr is of type IO [ () ],
730 -- a list of the bound values, coerced to ().
732 tcRnStmt hsc_env ictxt rdr_stmt
733 = initTcPrintErrors hsc_env iNTERACTIVE $
734 setInteractiveContext ictxt $ do {
736 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
737 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
738 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
741 -- The real work is done here
742 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
744 traceTc (text "tcs 1") ;
745 let { -- (a) Make all the bound ids "global" ids, now that
746 -- they're notionally top-level bindings. This is
747 -- important: otherwise when we come to compile an expression
748 -- using these ids later, the byte code generator will consider
749 -- the occurrences to be free rather than global.
751 -- (b) Tidy their types; this is important, because :info may
752 -- ask to look at them, and :info expects the things it looks
753 -- up to have tidy types
754 global_ids = map globaliseAndTidy bound_ids ;
756 -- Update the interactive context
757 rn_env = ic_rn_local_env ictxt ;
758 type_env = ic_type_env ictxt ;
760 bound_names = map idName global_ids ;
761 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
763 -- Remove any shadowed bindings from the type_env;
764 -- they are inaccessible but might, I suppose, cause
765 -- a space leak if we leave them there
766 shadowed = [ n | name <- bound_names,
767 let rdr_name = mkRdrUnqual (nameOccName name),
768 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
770 filtered_type_env = delListFromNameEnv type_env shadowed ;
771 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
773 new_ic = ictxt { ic_rn_local_env = new_rn_env,
774 ic_type_env = new_type_env }
777 dumpOptTcRn Opt_D_dump_tc
778 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
779 text "Typechecked expr" <+> ppr tc_expr]) ;
781 returnM (new_ic, bound_names, tc_expr)
784 globaliseAndTidy :: Id -> Id
786 -- Give the Id a Global Name, and tidy its type
787 = setIdType (globaliseId VanillaGlobal id) tidy_type
789 tidy_type = tidyTopType (idType id)
792 Here is the grand plan, implemented in tcUserStmt
794 What you type The IO [HValue] that hscStmt returns
795 ------------- ------------------------------------
796 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
799 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
802 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
803 [NB: result not printed] bindings: [it]
805 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
806 result showable) bindings: [it]
808 expr (of non-IO type,
809 result not showable) ==> error
813 ---------------------------
814 tcUserStmt :: LStmt Name -> TcM ([Id], LHsExpr Id)
815 tcUserStmt (L _ (ExprStmt expr _))
816 = newUnique `thenM` \ uniq ->
818 fresh_it = itName uniq
819 the_bind = noLoc $ FunBind (noLoc fresh_it) False
820 (mkMatchGroup [mkSimpleMatch [] expr])
822 tryTcLIE_ (do { -- Try this if the other fails
823 traceTc (text "tcs 1b") ;
825 nlLetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive],
826 nlExprStmt (nlHsApp (nlHsVar printName)
829 (do { -- Try this first
830 traceTc (text "tcs 1a") ;
831 tc_stmts [nlBindStmt (nlVarPat fresh_it) expr] })
833 tcUserStmt stmt = tc_stmts [stmt]
835 ---------------------------
837 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
839 ret_ty = mkListTy unitTy ;
840 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
842 names = map unLoc (collectStmtsBinders stmts) ;
844 stmt_ctxt = SC { sc_what = DoExpr,
846 sc_body = check_body,
849 infer_rhs rhs = do { (rhs', rhs_ty) <- tcInferRho rhs
850 ; [pat_ty] <- unifyTyConApp ioTyCon rhs_ty
851 ; return (rhs', pat_ty) } ;
852 check_body body = tcCheckRho body io_ret_ty ;
854 -- mk_return builds the expression
855 -- returnIO @ [()] [coerce () x, .., coerce () z]
857 -- Despite the inconvenience of building the type applications etc,
858 -- this *has* to be done in type-annotated post-typecheck form
859 -- because we are going to return a list of *polymorphic* values
860 -- coerced to type (). If we built a *source* stmt
861 -- return [coerce x, ..., coerce z]
862 -- then the type checker would instantiate x..z, and we wouldn't
863 -- get their *polymorphic* values. (And we'd get ambiguity errs
864 -- if they were overloaded, since they aren't applied to anything.)
865 mk_return ret_id ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
866 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
867 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
870 io_ty = mkTyConApp ioTyCon []
873 -- OK, we're ready to typecheck the stmts
874 traceTc (text "tcs 2") ;
875 ((ids, tc_expr), lie) <- getLIE $ do {
876 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
878 -- Look up the names right in the middle,
879 -- where they will all be in scope
880 ids <- mappM tcLookupId names ;
881 ret_id <- tcLookupId returnIOName ; -- return @ IO
882 return (ids, [nlResultStmt (mk_return ret_id ids)]) } ;
884 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
885 return (ids, noLoc (HsDo DoExpr tc_stmts io_ids io_ret_ty))
888 -- Simplify the context right here, so that we fail
889 -- if there aren't enough instances. Notably, when we see
891 -- we use recoverTc_ to try it <- e
892 -- and then let it = e
893 -- It's the simplify step that rejects the first.
894 traceTc (text "tcs 3") ;
895 const_binds <- tcSimplifyInteractive lie ;
897 -- Build result expression and zonk it
898 let { expr = mkHsLet const_binds tc_expr } ;
899 zonked_expr <- zonkTopLExpr expr ;
900 zonked_ids <- zonkTopBndrs ids ;
902 -- None of the Ids should be of unboxed type, because we
903 -- cast them all to HValues in the end!
904 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
906 return (zonked_ids, zonked_expr)
909 combine stmt (ids, stmts) = (ids, stmt:stmts)
910 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
911 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
915 tcRnExpr just finds the type of an expression
919 -> InteractiveContext
922 tcRnExpr hsc_env ictxt rdr_expr
923 = initTcPrintErrors hsc_env iNTERACTIVE $
924 setInteractiveContext ictxt $ do {
926 (rn_expr, fvs) <- rnLExpr rdr_expr ;
929 -- Now typecheck the expression;
930 -- it might have a rank-2 type (e.g. :t runST)
931 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
932 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
933 tcSimplifyInteractive lie_top ;
934 qtvs' <- mappM zonkQuantifiedTyVar qtvs ;
936 let { all_expr_ty = mkForAllTys qtvs' $
937 mkFunTys (map idType dict_ids) $
939 zonkTcType all_expr_ty
942 smpl_doc = ptext SLIT("main expression")
945 tcRnType just finds the kind of a type
949 -> InteractiveContext
952 tcRnType hsc_env ictxt rdr_type
953 = initTcPrintErrors hsc_env iNTERACTIVE $
954 setInteractiveContext ictxt $ do {
956 rn_type <- rnLHsType doc rdr_type ;
959 -- Now kind-check the type
960 (ty', kind) <- kcHsType rn_type ;
964 doc = ptext SLIT("In GHCi input")
970 %************************************************************************
972 More GHCi stuff, to do with browsing and getting info
974 %************************************************************************
978 mkExportEnv :: HscEnv -> [Module] -- Expose these modules' exports only
980 mkExportEnv hsc_env exports
981 = do { mb_envs <- initTcPrintErrors hsc_env iNTERACTIVE $
982 mappM getModuleExports exports
984 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
985 Nothing -> return emptyGlobalRdrEnv
986 -- Some error; initTc will have printed it
989 getModuleExports :: Module -> TcM GlobalRdrEnv
991 = do { iface <- load_iface mod
992 ; loadOrphanModules (dep_orphs (mi_deps iface))
993 -- Load any orphan-module interfaces,
994 -- so their instances are visible
995 ; names <- exportsToAvails (mi_exports iface)
996 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
997 | name <- nameSetToList names ] }
998 ; returnM (mkGlobalRdrEnv gres) }
1000 vanillaProv :: Module -> Provenance
1001 -- We're building a GlobalRdrEnv as if the user imported
1002 -- all the specified modules into the global interactive module
1003 vanillaProv mod = Imported [ImportSpec mod mod False
1004 (srcLocSpan interactiveSrcLoc)] False
1010 -> InteractiveContext
1011 -> Module -- Module to inspect
1012 -> Bool -- Grab just the exports, or the whole toplev
1013 -> IO (Maybe [IfaceDecl])
1015 getModuleContents hsc_env ictxt mod exports_only
1016 = initTcPrintErrors hsc_env iNTERACTIVE (get_mod_contents exports_only)
1018 get_mod_contents exports_only
1019 | not exports_only -- We want the whole top-level type env
1020 -- so it had better be a home module
1021 = do { hpt <- getHpt
1022 ; case lookupModuleEnv hpt mod of
1023 Just mod_info -> return (map toIfaceDecl $
1026 md_types (hm_details mod_info))
1027 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
1028 -- This is a system error; the module should be in the HPT
1031 | otherwise -- Want the exports only
1032 = do { iface <- load_iface mod
1033 ; mappM get_decl [ (mod,avail) | (mod, avails) <- mi_exports iface
1037 get_decl (mod, avail)
1038 = do { main_name <- lookupOrig mod (availName avail)
1039 ; thing <- tcLookupGlobal main_name
1040 ; return (filter_decl (availNames avail) (toIfaceDecl thing)) }
1042 ---------------------
1043 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
1044 = decl { ifSigs = filter (keep_sig occs) sigs }
1045 filter_decl occs decl@(IfaceData {ifCons = IfDataTyCon th cons})
1046 = decl { ifCons = IfDataTyCon th (filter (keep_con occs) cons) }
1047 filter_decl occs decl@(IfaceData {ifCons = IfNewTyCon con})
1048 | keep_con occs con = decl
1049 | otherwise = decl {ifCons = IfAbstractTyCon} -- Hmm?
1050 filter_decl occs decl
1053 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
1054 keep_con occs con = ifConOcc con `elem` occs
1056 wantToSee (AnId id) = not (isImplicitId id)
1057 wantToSee (ADataCon _) = False -- They'll come via their TyCon
1060 ---------------------
1061 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
1063 doc = ptext SLIT("context for compiling statements")
1065 ---------------------
1066 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1067 <+> quotes (ppr mod)
1071 tcRnGetInfo :: HscEnv
1072 -> InteractiveContext
1074 -> IO (Maybe [(IfaceDecl,
1076 [(IfaceInst, SrcLoc)])])
1077 -- Used to implemnent :info in GHCi
1079 -- Look up a RdrName and return all the TyThings it might be
1080 -- A capitalised RdrName is given to us in the DataName namespace,
1081 -- but we want to treat it as *both* a data constructor
1082 -- *and* as a type or class constructor;
1083 -- hence the call to dataTcOccs, and we return up to two results
1084 tcRnGetInfo hsc_env ictxt rdr_name
1085 = initTcPrintErrors hsc_env iNTERACTIVE $
1086 setInteractiveContext ictxt $ do {
1088 -- If the identifier is a constructor (begins with an
1089 -- upper-case letter), then we need to consider both
1090 -- constructor and type class identifiers.
1091 let { rdr_names = dataTcOccs rdr_name } ;
1093 -- results :: [(Messages, Maybe Name)]
1094 results <- mapM (tryTc . lookupOccRn) rdr_names ;
1096 traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]);
1097 -- The successful lookups will be (Just name)
1098 let { (warns_s, good_names) = unzip [ (msgs, name)
1099 | (msgs, Just name) <- results] ;
1100 errs_s = [msgs | (msgs, Nothing) <- results] } ;
1102 -- Fail if nothing good happened, else add warnings
1103 if null good_names then
1104 -- No lookup succeeded, so
1105 -- pick the first error message and report it
1106 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
1107 -- while the other is "X is not in scope",
1108 -- we definitely want the former; but we might pick the latter
1109 do { addMessages (head errs_s) ; failM }
1110 else -- Add deprecation warnings
1111 mapM_ addMessages warns_s ;
1113 -- And lookup up the entities, avoiding duplicates, which arise
1114 -- because constructors and record selectors are represented by
1115 -- their parent declaration
1116 let { do_one name = do { thing <- tcLookupGlobal name
1117 ; let decl = toIfaceDecl thing
1118 ; fixity <- lookupFixityRn name
1119 ; insts <- lookupInsts thing
1120 ; return (decl, fixity, getSrcLoc thing,
1121 map mk_inst insts) } ;
1122 -- For the SrcLoc, the 'thing' has better info than
1123 -- the 'name' because getting the former forced the
1124 -- declaration to be loaded into the cache
1125 mk_inst dfun = (dfunToIfaceInst dfun, getSrcLoc dfun) ;
1126 cmp (d1,_,_,_) (d2,_,_,_) = ifName d1 `compare` ifName d2 } ;
1127 results <- mapM do_one good_names ;
1128 return (fst (removeDups cmp results))
1131 lookupInsts :: TyThing -> TcM [DFunId]
1132 lookupInsts (AClass cls)
1133 = do { loadImportedInsts cls [] -- [] means load all instances for cls
1134 ; inst_envs <- tcGetInstEnvs
1135 ; return [df | (_,_,df) <- classInstances inst_envs cls] }
1137 lookupInsts (ATyCon tc)
1138 = do { eps <- getEps -- Load all instances for all classes that are
1139 -- in the type environment (which are all the ones
1140 -- we've seen in any interface file so far
1141 ; mapM_ (\c -> loadImportedInsts c [])
1142 (typeEnvClasses (eps_PTE eps))
1143 ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all
1144 ; return (get home_ie ++ get pkg_ie) }
1146 get ie = [df | (_,_,df) <- instEnvElts ie, relevant df]
1147 relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df)
1148 tc_name = tyConName tc
1150 lookupInsts other = return []
1153 toIfaceDecl :: TyThing -> IfaceDecl
1155 = tyThingToIfaceDecl True -- Discard IdInfo
1156 emptyNameSet -- Show data cons
1157 ext_nm (munge thing)
1159 ext_nm n = ExtPkg (nameModule n) (nameOccName n)
1161 -- munge transforms a thing to it's "parent" thing
1162 munge (ADataCon dc) = ATyCon (dataConTyCon dc)
1163 munge (AnId id) = case globalIdDetails id of
1164 RecordSelId tc lbl -> ATyCon tc
1165 ClassOpId cls -> AClass cls
1167 munge other_thing = other_thing
1172 %************************************************************************
1176 %************************************************************************
1179 rnDump :: SDoc -> TcRn ()
1180 -- Dump, with a banner, if -ddump-rn
1181 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1183 tcDump :: TcGblEnv -> TcRn ()
1185 = do { dflags <- getDOpts ;
1187 -- Dump short output if -ddump-types or -ddump-tc
1188 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1189 (dumpTcRn short_dump) ;
1191 -- Dump bindings if -ddump-tc
1192 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1195 short_dump = pprTcGblEnv env
1196 full_dump = pprLHsBinds (tcg_binds env)
1197 -- NB: foreign x-d's have undefined's in their types;
1198 -- hence can't show the tc_fords
1201 = do { dflags <- getDOpts ;
1202 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1203 (dumpTcRn (pprModGuts mod_guts)) ;
1205 -- Dump bindings if -ddump-tc
1206 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1208 full_dump = pprCoreBindings (mg_binds mod_guts)
1210 -- It's unpleasant having both pprModGuts and pprModDetails here
1211 pprTcGblEnv :: TcGblEnv -> SDoc
1212 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1213 tcg_insts = dfun_ids,
1215 tcg_imports = imports })
1216 = vcat [ ppr_types dfun_ids type_env
1217 , ppr_insts dfun_ids
1218 , vcat (map ppr rules)
1219 , ppr_gen_tycons (typeEnvTyCons type_env)
1220 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1221 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1223 pprModGuts :: ModGuts -> SDoc
1224 pprModGuts (ModGuts { mg_types = type_env,
1226 = vcat [ ppr_types [] type_env,
1230 ppr_types :: [Var] -> TypeEnv -> SDoc
1231 ppr_types dfun_ids type_env
1232 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1234 ids = [id | id <- typeEnvIds type_env, want_sig id]
1235 want_sig id | opt_PprStyle_Debug = True
1236 | otherwise = isLocalId id &&
1237 isExternalName (idName id) &&
1238 not (id `elem` dfun_ids)
1239 -- isLocalId ignores data constructors, records selectors etc.
1240 -- The isExternalName ignores local dictionary and method bindings
1241 -- that the type checker has invented. Top-level user-defined things
1242 -- have External names.
1244 ppr_insts :: [Var] -> SDoc
1245 ppr_insts [] = empty
1246 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1248 ppr_sigs :: [Var] -> SDoc
1250 -- Print type signatures; sort by OccName
1251 = vcat (map ppr_sig (sortLe le_sig ids))
1253 le_sig id1 id2 = getOccName id1 <= getOccName id2
1254 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1256 ppr_rules :: [IdCoreRule] -> SDoc
1257 ppr_rules [] = empty
1258 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1259 nest 4 (pprIdRules rs),
1262 ppr_gen_tycons [] = empty
1263 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1264 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]