2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
9 mkExportEnv, getModuleContents, tcRnStmt, tcRnThing, tcRnExpr,
16 #include "HsVersions.h"
19 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
22 import CmdLineOpts ( DynFlag(..), opt_PprStyle_Debug, dopt )
23 import DriverState ( v_MainModIs, v_MainFunIs )
25 import RdrHsSyn ( findSplice )
27 import PrelNames ( runIOName, rootMainName, mAIN_Name,
29 import RdrName ( RdrName, mkRdrUnqual, emptyGlobalRdrEnv,
31 import TcHsSyn ( zonkTopDecls )
32 import TcExpr ( tcInferRho )
34 import TcType ( tidyTopType )
35 import Inst ( showLIE )
36 import TcBinds ( tcTopBinds )
37 import TcDefaults ( tcDefaults )
38 import TcEnv ( tcExtendGlobalValEnv, tcLookupGlobal )
39 import TcRules ( tcRules )
40 import TcForeign ( tcForeignImports, tcForeignExports )
41 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
42 import TcIface ( tcExtCoreBindings )
43 import TcSimplify ( tcSimplifyTop )
44 import TcTyClsDecls ( tcTyAndClassDecls )
45 import LoadIface ( loadOrphanModules )
46 import RnNames ( importsFromLocalDecls, rnImports, exportsFromAvail,
47 reportUnusedNames, reportDeprecations )
48 import RnEnv ( lookupSrcOcc_maybe )
49 import RnSource ( rnSrcDecls, rnTyClDecls, checkModDeprec )
50 import PprCore ( pprIdRules, pprCoreBindings )
51 import CoreSyn ( IdCoreRule, bindersOfBinds )
52 import ErrUtils ( mkDumpDoc, showPass )
53 import Id ( mkExportedLocalId, isLocalId, idName, idType )
55 import Module ( mkHomeModule, mkModuleName, moduleName, moduleEnvElts )
56 import OccName ( mkVarOcc )
57 import Name ( Name, isExternalName, getSrcLoc, getOccName )
59 import TyCon ( tyConHasGenerics )
60 import SrcLoc ( srcLocSpan, Located(..), noLoc )
62 import HscTypes ( ModGuts(..), HscEnv(..),
63 GhciMode(..), noDependencies,
64 Deprecs( NoDeprecs ), plusDeprecs,
65 GenAvailInfo(Avail), availsToNameSet, availName,
66 ForeignStubs(NoStubs), TypeEnv, typeEnvTyCons,
67 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
71 import HsSyn ( HsStmtContext(..),
73 collectStmtsBinders, mkSimpleMatch, placeHolderType )
74 import RdrName ( GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
75 Provenance(..), ImportSpec(..),
76 lookupLocalRdrEnv, extendLocalRdrEnv )
77 import RnSource ( addTcgDUs )
78 import TcHsSyn ( mkHsLet, zonkTopLExpr, zonkTopBndrs )
79 import TcExpr ( tcCheckRho )
80 import TcMType ( zonkTcType )
81 import TcMatches ( tcStmtsAndThen, TcStmtCtxt(..) )
82 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
83 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType )
84 import TcEnv ( tcLookupTyCon, tcLookupId )
85 import TyCon ( DataConDetails(..) )
86 import Inst ( tcStdSyntaxName )
87 import RnExpr ( rnStmts, rnLExpr )
88 import RnNames ( exportsToAvails )
89 import LoadIface ( loadSrcInterface )
90 import IfaceSyn ( IfaceDecl(..), IfaceClassOp(..), IfaceConDecl(..), IfaceExtName(..),
92 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
93 import Id ( Id, isImplicitId )
94 import MkId ( unsafeCoerceId )
95 import TysWiredIn ( mkListTy, unitTy )
96 import IdInfo ( GlobalIdDetails(..) )
97 import SrcLoc ( interactiveSrcLoc, unLoc )
98 import Var ( globaliseId )
99 import Name ( nameOccName, nameModuleName )
100 import NameEnv ( delListFromNameEnv )
101 import PrelNames ( iNTERACTIVE, ioTyConName, printName, monadNames, itName, returnIOName )
102 import Module ( ModuleName, lookupModuleEnvByName )
103 import HscTypes ( InteractiveContext(..),
104 HomeModInfo(..), typeEnvElts,
105 TyThing(..), availNames, icPrintUnqual,
106 ModIface(..), ModDetails(..) )
107 import BasicTypes ( RecFlag(..), Fixity )
108 import Bag ( unitBag )
109 import Panic ( ghcError, GhcException(..) )
112 import FastString ( mkFastString )
113 import Util ( sortLt )
114 import Bag ( unionBags, snocBag )
116 import Maybe ( isJust )
121 %************************************************************************
123 Typecheck and rename a module
125 %************************************************************************
130 -> Located (HsModule RdrName)
131 -> IO (Maybe TcGblEnv)
133 tcRnModule hsc_env (L loc (HsModule maybe_mod exports
134 import_decls local_decls mod_deprec))
135 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
137 let { this_mod = case maybe_mod of
138 Nothing -> mkHomeModule mAIN_Name
139 -- 'module M where' is omitted
140 Just (L _ mod) -> mod } ;
143 initTc hsc_env this_mod $
145 do { -- Deal with imports; sets tcg_rdr_env, tcg_imports
146 (rdr_env, imports) <- rnImports import_decls ;
147 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
148 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
150 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
151 -- Fail if there are any errors so far
152 -- The error printing (if needed) takes advantage
153 -- of the tcg_env we have now set
156 -- Load any orphan-module interfaces, so that
157 -- their rules and instance decls will be found
158 loadOrphanModules (imp_orphs imports) ;
160 traceRn (text "rn1a") ;
161 -- Rename and type check the declarations
162 tcg_env <- tcRnSrcDecls local_decls ;
163 setGblEnv tcg_env $ do {
165 traceRn (text "rn3") ;
167 -- Report the use of any deprecated things
168 -- We do this before processsing the export list so
169 -- that we don't bleat about re-exporting a deprecated
170 -- thing (especially via 'module Foo' export item)
171 -- Only uses in the body of the module are complained about
172 reportDeprecations tcg_env ;
174 -- Process the export list
175 export_avails <- exportsFromAvail (isJust maybe_mod) exports ;
177 -- Get any supporting decls for the exports that have not already
178 -- been sucked in for the declarations in the body of the module.
179 -- (This can happen if something is imported only to be re-exported.)
181 -- Importing these supporting declarations is required
182 -- *only* to gether usage information
183 -- (see comments with MkIface.mkImportInfo for why)
184 -- We don't need the results, but sucking them in may side-effect
185 -- the ExternalPackageState, apart from recording usage
186 mappM (tcLookupGlobal . availName) export_avails ;
188 -- Check whether the entire module is deprecated
189 -- This happens only once per module
190 let { mod_deprecs = checkModDeprec mod_deprec } ;
192 -- Add exports and deprecations to envt
193 let { export_fvs = availsToNameSet export_avails ;
194 final_env = tcg_env { tcg_exports = export_avails,
195 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly export_fvs,
196 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
198 -- A module deprecation over-rides the earlier ones
201 -- Report unused names
202 reportUnusedNames final_env ;
204 -- Dump output and return
211 %************************************************************************
213 The interactive interface
215 %************************************************************************
220 -> InteractiveContext
222 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
223 -- The returned [Name] is the same as the input except for
224 -- ExprStmt, in which case the returned [Name] is [itName]
226 -- The returned TypecheckedHsExpr is of type IO [ () ],
227 -- a list of the bound values, coerced to ().
229 tcRnStmt hsc_env ictxt rdr_stmt
230 = initTc hsc_env iNTERACTIVE $
231 setInteractiveContext ictxt $ do {
233 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
234 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
235 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
238 -- The real work is done here
239 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
241 traceTc (text "tcs 1") ;
242 let { -- Make all the bound ids "global" ids, now that
243 -- they're notionally top-level bindings. This is
244 -- important: otherwise when we come to compile an expression
245 -- using these ids later, the byte code generator will consider
246 -- the occurrences to be free rather than global.
247 global_ids = map (globaliseId VanillaGlobal) bound_ids ;
249 -- Update the interactive context
250 rn_env = ic_rn_local_env ictxt ;
251 type_env = ic_type_env ictxt ;
253 bound_names = map idName global_ids ;
254 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
256 -- Remove any shadowed bindings from the type_env;
257 -- they are inaccessible but might, I suppose, cause
258 -- a space leak if we leave them there
259 shadowed = [ n | name <- bound_names,
260 let rdr_name = mkRdrUnqual (nameOccName name),
261 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
263 filtered_type_env = delListFromNameEnv type_env shadowed ;
264 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
266 new_ic = ictxt { ic_rn_local_env = new_rn_env,
267 ic_type_env = new_type_env }
270 dumpOptTcRn Opt_D_dump_tc
271 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
272 text "Typechecked expr" <+> ppr tc_expr]) ;
274 returnM (new_ic, bound_names, tc_expr)
279 Here is the grand plan, implemented in tcUserStmt
281 What you type The IO [HValue] that hscStmt returns
282 ------------- ------------------------------------
283 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
286 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
289 expr (of IO type) ==> expr >>= \ v -> return [coerce HVal v]
290 [NB: result not printed] bindings: [it]
292 expr (of non-IO type, ==> let v = expr in print v >> return [coerce HVal v]
293 result showable) bindings: [it]
295 expr (of non-IO type,
296 result not showable) ==> error
300 ---------------------------
301 tcUserStmt :: LStmt Name -> TcM ([Id], LHsExpr Id)
302 tcUserStmt (L _ (ExprStmt expr _))
303 = newUnique `thenM` \ uniq ->
305 fresh_it = itName uniq
306 the_bind = noLoc $ FunBind (noLoc fresh_it) False
307 [ mkSimpleMatch [] expr placeHolderType ]
309 tryTcLIE_ (do { -- Try this if the other fails
310 traceTc (text "tcs 1b") ;
312 nlLetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive],
313 nlExprStmt (nlHsApp (nlHsVar printName)
316 (do { -- Try this first
317 traceTc (text "tcs 1a") ;
318 tc_stmts [nlBindStmt (nlVarPat fresh_it) expr] })
320 tcUserStmt stmt = tc_stmts [stmt]
322 ---------------------------
324 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
326 ret_ty = mkListTy unitTy ;
327 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
329 names = map unLoc (collectStmtsBinders stmts) ;
331 stmt_ctxt = SC { sc_what = DoExpr,
333 sc_body = check_body,
336 check_rhs rhs rhs_ty = tcCheckRho rhs (mkTyConApp ioTyCon [rhs_ty]) ;
337 check_body body = tcCheckRho body io_ret_ty ;
339 -- mk_return builds the expression
340 -- returnIO @ [()] [coerce () x, .., coerce () z]
342 -- Despite the inconvenience of building the type applications etc,
343 -- this *has* to be done in type-annotated post-typecheck form
344 -- because we are going to return a list of *polymorphic* values
345 -- coerced to type (). If we built a *source* stmt
346 -- return [coerce x, ..., coerce z]
347 -- then the type checker would instantiate x..z, and we wouldn't
348 -- get their *polymorphic* values. (And we'd get ambiguity errs
349 -- if they were overloaded, since they aren't applied to anything.)
350 mk_return ret_id ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
351 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
352 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
355 io_ty = mkTyConApp ioTyCon []
358 -- OK, we're ready to typecheck the stmts
359 traceTc (text "tcs 2") ;
360 ((ids, tc_expr), lie) <- getLIE $ do {
361 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
363 -- Look up the names right in the middle,
364 -- where they will all be in scope
365 ids <- mappM tcLookupId names ;
366 ret_id <- tcLookupId returnIOName ; -- return @ IO
367 return (ids, [nlResultStmt (mk_return ret_id ids)]) } ;
369 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
370 return (ids, noLoc (HsDo DoExpr tc_stmts io_ids io_ret_ty))
373 -- Simplify the context right here, so that we fail
374 -- if there aren't enough instances. Notably, when we see
376 -- we use recoverTc_ to try it <- e
377 -- and then let it = e
378 -- It's the simplify step that rejects the first.
379 traceTc (text "tcs 3") ;
380 const_binds <- tcSimplifyInteractive lie ;
382 -- Build result expression and zonk it
383 let { expr = mkHsLet const_binds tc_expr } ;
384 zonked_expr <- zonkTopLExpr expr ;
385 zonked_ids <- zonkTopBndrs ids ;
387 return (zonked_ids, zonked_expr)
390 combine stmt (ids, stmts) = (ids, stmt:stmts)
394 tcRnExpr just finds the type of an expression
398 -> InteractiveContext
401 tcRnExpr hsc_env ictxt rdr_expr
402 = initTc hsc_env iNTERACTIVE $
403 setInteractiveContext ictxt $ do {
405 (rn_expr, fvs) <- rnLExpr rdr_expr ;
408 -- Now typecheck the expression;
409 -- it might have a rank-2 type (e.g. :t runST)
410 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
411 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
412 tcSimplifyInteractive lie_top ;
414 let { all_expr_ty = mkForAllTys qtvs $
415 mkFunTys (map idType dict_ids) $
417 zonkTcType all_expr_ty
420 smpl_doc = ptext SLIT("main expression")
426 -> InteractiveContext
428 -> IO (Maybe [(IfaceDecl, Fixity)])
429 -- Look up a RdrName and return all the TyThings it might be
430 -- A capitalised RdrName is given to us in the DataName namespace,
431 -- but we want to treat it as *both* a data constructor
432 -- *and* as a type or class constructor;
433 -- hence the call to dataTcOccs, and we return up to two results
434 tcRnThing hsc_env ictxt rdr_name
435 = initTc hsc_env iNTERACTIVE $
436 setInteractiveContext ictxt $ do {
438 -- If the identifier is a constructor (begins with an
439 -- upper-case letter), then we need to consider both
440 -- constructor and type class identifiers.
441 let { rdr_names = dataTcOccs rdr_name } ;
443 -- results :: [(Messages, Maybe Name)]
444 results <- mapM (tryTc . lookupOccRn) rdr_names ;
446 -- The successful lookups will be (Just name)
447 let { (warns_s, good_names) = unzip [ (msgs, name)
448 | (msgs, Just name) <- results] ;
449 errs_s = [msgs | (msgs, Nothing) <- results] } ;
451 -- Fail if nothing good happened, else add warnings
452 if null good_names then
453 -- No lookup succeeded, so
454 -- pick the first error message and report it
455 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
456 -- while the other is "X is not in scope",
457 -- we definitely want the former; but we might pick the latter
458 do { addMessages (head errs_s) ; failM }
459 else -- Add deprecation warnings
460 mapM_ addMessages warns_s ;
462 -- And lookup up the entities
463 mapM do_one good_names
466 do_one name = do { thing <- tcLookupGlobal name
467 ; fixity <- lookupFixityRn name
468 ; return (toIfaceDecl ictxt thing, fixity) }
470 toIfaceDecl :: InteractiveContext -> TyThing -> IfaceDecl
471 toIfaceDecl ictxt thing
472 = tyThingToIfaceDecl True {- Discard IdInfo -} ext_nm thing
474 unqual = icPrintUnqual ictxt
475 ext_nm n | unqual n = LocalTop (nameOccName n) -- What a hack
476 | otherwise = ExtPkg (nameModuleName n) (nameOccName n)
481 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
482 setInteractiveContext icxt thing_inside
483 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
484 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
485 tcg_type_env = ic_type_env icxt}) $
486 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
491 %************************************************************************
493 Type-checking external-core modules
495 %************************************************************************
498 tcRnExtCore :: HscEnv
500 -> IO (Maybe ModGuts)
501 -- Nothing => some error occurred
503 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
504 -- The decls are IfaceDecls; all names are original names
505 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
507 initTc hsc_env this_mod $ do {
509 let { ldecls = map noLoc decls } ;
511 -- Deal with the type declarations; first bring their stuff
512 -- into scope, then rname them, then type check them
513 (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup ldecls) ;
515 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
516 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
519 rn_decls <- rnTyClDecls ldecls ;
522 -- Dump trace of renaming part
523 rnDump (ppr rn_decls) ;
525 -- Typecheck them all together so that
526 -- any mutually recursive types are done right
527 tcg_env <- checkNoErrs (tcTyAndClassDecls rn_decls) ;
528 -- Make the new type env available to stuff slurped from interface files
530 setGblEnv tcg_env $ do {
532 -- Now the core bindings
533 core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;
537 bndrs = bindersOfBinds core_binds ;
538 my_exports = map (Avail . idName) bndrs ;
539 -- ToDo: export the data types also?
541 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
543 mod_guts = ModGuts { mg_module = this_mod,
544 mg_usages = [], -- ToDo: compute usage
545 mg_dir_imps = [], -- ??
546 mg_deps = noDependencies, -- ??
547 mg_exports = my_exports,
548 mg_types = final_type_env,
549 mg_insts = tcg_insts tcg_env,
551 mg_binds = core_binds,
554 mg_rdr_env = emptyGlobalRdrEnv,
555 mg_fix_env = emptyFixityEnv,
556 mg_deprecs = NoDeprecs,
560 tcCoreDump mod_guts ;
565 mkFakeGroup decls -- Rather clumsy; lots of unused fields
566 = HsGroup { hs_tyclds = decls, -- This is the one we want
567 hs_valds = [], hs_fords = [],
568 hs_instds = [], hs_fixds = [], hs_depds = [],
569 hs_ruleds = [], hs_defds = [] }
573 %************************************************************************
575 Type-checking the top level of a module
577 %************************************************************************
580 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
581 -- Returns the variables free in the decls
582 -- Reason: solely to report unused imports and bindings
584 = do { -- Do all the declarations
585 (tc_envs, lie) <- getLIE (tc_rn_src_decls decls) ;
587 -- tcSimplifyTop deals with constant or ambiguous InstIds.
588 -- How could there be ambiguous ones? They can only arise if a
589 -- top-level decl falls under the monomorphism
590 -- restriction, and no subsequent decl instantiates its
591 -- type. (Usually, ambiguous type variables are resolved
592 -- during the generalisation step.)
593 traceTc (text "Tc8") ;
594 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
595 -- Setting the global env exposes the instances to tcSimplifyTop
596 -- Setting the local env exposes the local Ids to tcSimplifyTop,
597 -- so that we get better error messages (monomorphism restriction)
599 -- Backsubstitution. This must be done last.
600 -- Even tcSimplifyTop may do some unification.
601 traceTc (text "Tc9") ;
602 let { (tcg_env, _) = tc_envs ;
603 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
604 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
606 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
609 let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
611 -- Make the new type env available to stuff slurped from interface files
612 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
614 return (tcg_env { tcg_type_env = final_type_env,
615 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' })
618 tc_rn_src_decls :: [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
619 -- Loops around dealing with each top level inter-splice group
620 -- in turn, until it's dealt with the entire module
622 = do { let { (first_group, group_tail) = findSplice ds } ;
623 -- If ds is [] we get ([], Nothing)
625 -- Type check the decls up to, but not including, the first splice
626 tc_envs@(tcg_env,tcl_env) <- tcRnGroup first_group ;
628 -- Bale out if errors; for example, error recovery when checking
629 -- the RHS of 'main' can mean that 'main' is not in the envt for
630 -- the subsequent checkMain test
635 -- If there is no splice, we're nearly done
637 Nothing -> do { -- Last thing: check for `main'
638 tcg_env <- checkMain ;
639 return (tcg_env, tcl_env)
642 -- If there's a splice, we must carry on
643 Just (SpliceDecl splice_expr, rest_ds) -> do {
645 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
648 -- Rename the splice expression, and get its supporting decls
649 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
650 failIfErrsM ; -- Don't typecheck if renaming failed
652 -- Execute the splice
653 spliced_decls <- tcSpliceDecls rn_splice_expr ;
655 -- Glue them on the front of the remaining decls and loop
656 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
657 tc_rn_src_decls (spliced_decls ++ rest_ds)
663 %************************************************************************
665 Type-checking the top level of a module
667 %************************************************************************
669 tcRnGroup takes a bunch of top-level source-code declarations, and
671 * gets supporting declarations from interface files
674 * and augments the TcGblEnv with the results
676 In Template Haskell it may be called repeatedly for each group of
677 declarations. It expects there to be an incoming TcGblEnv in the
678 monad; it augments it and returns the new TcGblEnv.
681 tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
682 -- Returns the variables free in the decls, for unused-binding reporting
684 = do { -- Rename the declarations
685 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
686 setGblEnv tcg_env $ do {
688 -- Typecheck the declarations
689 tcTopSrcDecls rn_decls
692 ------------------------------------------------
693 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
695 = do { -- Bring top level binders into scope
696 (rdr_env, imports) <- importsFromLocalDecls group ;
697 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
698 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
701 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
702 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
704 -- Rename the source decls
705 (tcg_env, rn_decls) <- rnSrcDecls group ;
708 -- Dump trace of renaming part
709 rnDump (ppr rn_decls) ;
711 return (tcg_env, rn_decls)
714 ------------------------------------------------
715 tcTopSrcDecls :: HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
717 (HsGroup { hs_tyclds = tycl_decls,
718 hs_instds = inst_decls,
719 hs_fords = foreign_decls,
720 hs_defds = default_decls,
721 hs_ruleds = rule_decls,
722 hs_valds = val_binds })
723 = do { -- Type-check the type and class decls, and all imported decls
724 -- The latter come in via tycl_decls
725 traceTc (text "Tc2") ;
727 tcg_env <- checkNoErrs (tcTyAndClassDecls tycl_decls) ;
728 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
729 -- an error we'd better stop now, to avoid a cascade
731 -- Make these type and class decls available to stuff slurped from interface files
732 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
735 setGblEnv tcg_env $ do {
736 -- Source-language instances, including derivings,
737 -- and import the supporting declarations
738 traceTc (text "Tc3") ;
739 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
740 setGblEnv tcg_env $ do {
742 -- Foreign import declarations next. No zonking necessary
743 -- here; we can tuck them straight into the global environment.
744 traceTc (text "Tc4") ;
745 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
746 tcExtendGlobalValEnv fi_ids $ do {
748 -- Default declarations
749 traceTc (text "Tc4a") ;
750 default_tys <- tcDefaults default_decls ;
751 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
753 -- Value declarations next
754 -- We also typecheck any extra binds that came out
755 -- of the "deriving" process (deriv_binds)
756 traceTc (text "Tc5") ;
757 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
758 setLclTypeEnv lcl_env $ do {
760 -- Second pass over class and instance declarations,
761 traceTc (text "Tc6") ;
762 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
763 showLIE (text "after instDecls2") ;
766 -- They need to be zonked, so we return them
767 traceTc (text "Tc7") ;
768 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
771 rules <- tcRules rule_decls ;
774 traceTc (text "Tc7a") ;
775 tcg_env <- getGblEnv ;
776 let { all_binds = tc_val_binds `unionBags`
777 inst_binds `unionBags`
780 -- Extend the GblEnv with the (as yet un-zonked)
781 -- bindings, rules, foreign decls
782 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
783 tcg_rules = tcg_rules tcg_env ++ rules,
784 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
785 return (tcg_env', lcl_env)
790 %*********************************************************
792 mkGlobalContext: make up an interactive context
794 Used for initialising the lexical environment
795 of the interactive read-eval-print loop
797 %*********************************************************
801 mkExportEnv :: HscEnv -> [ModuleName] -- Expose these modules' exports only
804 mkExportEnv hsc_env exports
805 = do { mb_envs <- initTc hsc_env iNTERACTIVE $
806 mappM getModuleExports exports
808 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
809 Nothing -> return emptyGlobalRdrEnv
810 -- Some error; initTc will have printed it
813 getModuleExports :: ModuleName -> TcM GlobalRdrEnv
815 = do { iface <- load_iface mod
816 ; avails <- exportsToAvails (mi_exports iface)
817 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
818 | avail <- avails, name <- availNames avail ] }
819 ; returnM (mkGlobalRdrEnv gres) }
821 vanillaProv :: ModuleName -> Provenance
822 -- We're building a GlobalRdrEnv as if the user imported
823 -- all the specified modules into the global interactive module
824 vanillaProv mod = Imported [ImportSpec mod mod False
825 (srcLocSpan interactiveSrcLoc)] False
831 -> InteractiveContext
832 -> ModuleName -- Module to inspect
833 -> Bool -- Grab just the exports, or the whole toplev
834 -> IO (Maybe [IfaceDecl])
836 getModuleContents hsc_env ictxt mod exports_only
837 = initTc hsc_env iNTERACTIVE (get_mod_contents exports_only)
839 get_mod_contents exports_only
840 | not exports_only -- We want the whole top-level type env
841 -- so it had better be a home module
843 ; case lookupModuleEnvByName hpt mod of
844 Just mod_info -> return (map (toIfaceDecl ictxt) $
847 md_types (hm_details mod_info))
848 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
849 -- This is a system error; the module should be in the HPT
852 | otherwise -- Want the exports only
853 = do { iface <- load_iface mod
854 ; avails <- exportsToAvails (mi_exports iface)
855 ; mappM get_decl avails
859 = do { thing <- tcLookupGlobal (availName avail)
860 ; return (filter_decl (availOccs avail) (toIfaceDecl ictxt thing)) }
862 ---------------------
863 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
864 = decl { ifSigs = filter (keep_sig occs) sigs }
865 filter_decl occs decl@(IfaceData {ifCons = DataCons cons})
866 = decl { ifCons = DataCons (filter (keep_con occs) cons) }
867 filter_decl occs decl
870 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
871 keep_con occs (IfaceConDecl occ _ _ _ _ _) = occ `elem` occs
873 availOccs avail = map nameOccName (availNames avail)
875 wantToSee (AnId id) = not (isImplicitId id)
876 wantToSee (ADataCon _) = False -- They'll come via their TyCon
879 ---------------------
880 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
882 doc = ptext SLIT("context for compiling statements")
884 ---------------------
885 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
890 %************************************************************************
894 %************************************************************************
898 = do { ghci_mode <- getGhciMode ;
899 tcg_env <- getGblEnv ;
901 mb_main_mod <- readMutVar v_MainModIs ;
902 mb_main_fn <- readMutVar v_MainFunIs ;
903 let { main_mod = case mb_main_mod of {
904 Just mod -> mkModuleName mod ;
905 Nothing -> mAIN_Name } ;
906 main_fn = case mb_main_fn of {
907 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
908 Nothing -> main_RDR_Unqual } } ;
910 check_main ghci_mode tcg_env main_mod main_fn
914 check_main ghci_mode tcg_env main_mod main_fn
915 -- If we are in module Main, check that 'main' is defined.
916 -- It may be imported from another module!
918 -- ToDo: We have to return the main_name separately, because it's a
919 -- bona fide 'use', and should be recorded as such, but the others
922 -- Blimey: a whole page of code to do this...
923 | mod_name /= main_mod
927 = addErrCtxt mainCtxt $
928 do { mb_main <- lookupSrcOcc_maybe main_fn
929 -- Check that 'main' is in scope
930 -- It might be imported from another module!
932 Nothing -> do { complain_no_main
935 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
936 -- :Main.main :: IO () = runIO main
938 ; (main_expr, ty) <- addSrcSpan (srcLocSpan (getSrcLoc main_name)) $
941 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
942 main_bind = noLoc (VarBind root_main_id main_expr) }
944 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
946 tcg_dus = tcg_dus tcg_env
947 `plusDU` usesOnly (unitFV main_name)
951 mod_name = moduleName (tcg_mod tcg_env)
953 complain_no_main | ghci_mode == Interactive = return ()
954 | otherwise = failWithTc noMainMsg
955 -- In interactive mode, don't worry about the absence of 'main'
956 -- In other modes, fail altogether, so that we don't go on
957 -- and complain a second time when processing the export list.
959 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
960 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
961 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
965 %************************************************************************
969 %************************************************************************
972 rnDump :: SDoc -> TcRn ()
973 -- Dump, with a banner, if -ddump-rn
974 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
976 tcDump :: TcGblEnv -> TcRn ()
978 = do { dflags <- getDOpts ;
980 -- Dump short output if -ddump-types or -ddump-tc
981 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
982 (dumpTcRn short_dump) ;
984 -- Dump bindings if -ddump-tc
985 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
988 short_dump = pprTcGblEnv env
989 full_dump = ppr (tcg_binds env)
990 -- NB: foreign x-d's have undefined's in their types;
991 -- hence can't show the tc_fords
994 = do { dflags <- getDOpts ;
995 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
996 (dumpTcRn (pprModGuts mod_guts)) ;
998 -- Dump bindings if -ddump-tc
999 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1001 full_dump = pprCoreBindings (mg_binds mod_guts)
1003 -- It's unpleasant having both pprModGuts and pprModDetails here
1004 pprTcGblEnv :: TcGblEnv -> SDoc
1005 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1006 tcg_insts = dfun_ids,
1008 tcg_imports = imports })
1009 = vcat [ ppr_types dfun_ids type_env
1010 , ppr_insts dfun_ids
1011 , vcat (map ppr rules)
1012 , ppr_gen_tycons (typeEnvTyCons type_env)
1013 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1014 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1016 pprModGuts :: ModGuts -> SDoc
1017 pprModGuts (ModGuts { mg_types = type_env,
1019 = vcat [ ppr_types [] type_env,
1023 ppr_types :: [Var] -> TypeEnv -> SDoc
1024 ppr_types dfun_ids type_env
1025 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1027 ids = [id | id <- typeEnvIds type_env, want_sig id]
1028 want_sig id | opt_PprStyle_Debug = True
1029 | otherwise = isLocalId id &&
1030 isExternalName (idName id) &&
1031 not (id `elem` dfun_ids)
1032 -- isLocalId ignores data constructors, records selectors etc.
1033 -- The isExternalName ignores local dictionary and method bindings
1034 -- that the type checker has invented. Top-level user-defined things
1035 -- have External names.
1037 ppr_insts :: [Var] -> SDoc
1038 ppr_insts [] = empty
1039 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1041 ppr_sigs :: [Var] -> SDoc
1043 -- Print type signatures; sort by OccName
1044 = vcat (map ppr_sig (sortLt lt_sig ids))
1046 lt_sig id1 id2 = getOccName id1 < getOccName id2
1047 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1049 ppr_rules :: [IdCoreRule] -> SDoc
1050 ppr_rules [] = empty
1051 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1052 nest 4 (pprIdRules rs),
1055 ppr_gen_tycons [] = empty
1056 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1057 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]