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 ( Messages, 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(..),
91 IfaceExtName(..), IfaceConDecls(..),
93 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
94 import Id ( Id, isImplicitId )
95 import MkId ( unsafeCoerceId )
96 import TysWiredIn ( mkListTy, unitTy )
97 import IdInfo ( GlobalIdDetails(..) )
98 import SrcLoc ( interactiveSrcLoc, unLoc )
99 import Var ( globaliseId )
100 import Name ( nameOccName, nameModuleName )
101 import NameEnv ( delListFromNameEnv )
102 import PrelNames ( iNTERACTIVE, ioTyConName, printName, monadNames, itName, returnIOName )
103 import Module ( ModuleName, lookupModuleEnvByName )
104 import HscTypes ( InteractiveContext(..),
105 HomeModInfo(..), typeEnvElts,
106 TyThing(..), availNames, icPrintUnqual,
107 ModIface(..), ModDetails(..) )
108 import BasicTypes ( RecFlag(..), Fixity )
109 import Bag ( unitBag )
110 import Panic ( ghcError, GhcException(..) )
113 import FastString ( mkFastString )
114 import Util ( sortLt )
115 import Bag ( unionBags, snocBag )
117 import Maybe ( isJust )
122 %************************************************************************
124 Typecheck and rename a module
126 %************************************************************************
131 -> Located (HsModule RdrName)
132 -> IO (Messages, Maybe TcGblEnv)
134 tcRnModule hsc_env (L loc (HsModule maybe_mod exports
135 import_decls local_decls mod_deprec))
136 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
138 let { this_mod = case maybe_mod of
139 Nothing -> mkHomeModule mAIN_Name
140 -- 'module M where' is omitted
141 Just (L _ mod) -> mod } ;
144 initTc hsc_env this_mod $
146 do { -- Deal with imports; sets tcg_rdr_env, tcg_imports
147 (rdr_env, imports) <- rnImports import_decls ;
148 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
149 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
151 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
152 -- Fail if there are any errors so far
153 -- The error printing (if needed) takes advantage
154 -- of the tcg_env we have now set
157 -- Load any orphan-module interfaces, so that
158 -- their rules and instance decls will be found
159 loadOrphanModules (imp_orphs imports) ;
161 traceRn (text "rn1a") ;
162 -- Rename and type check the declarations
163 tcg_env <- tcRnSrcDecls local_decls ;
164 setGblEnv tcg_env $ do {
166 traceRn (text "rn3") ;
168 -- Report the use of any deprecated things
169 -- We do this before processsing the export list so
170 -- that we don't bleat about re-exporting a deprecated
171 -- thing (especially via 'module Foo' export item)
172 -- Only uses in the body of the module are complained about
173 reportDeprecations tcg_env ;
175 -- Process the export list
176 exports <- exportsFromAvail (isJust maybe_mod) exports ;
178 {- Jan 04: I don't think this is necessary any more; usage info is derived from tcg_dus
179 -- Get any supporting decls for the exports that have not already
180 -- been sucked in for the declarations in the body of the module.
181 -- (This can happen if something is imported only to be re-exported.)
183 -- Importing these supporting declarations is required
184 -- *only* to gether usage information
185 -- (see comments with MkIface.mkImportInfo for why)
186 -- We don't need the results, but sucking them in may side-effect
187 -- the ExternalPackageState, apart from recording usage
188 mappM (tcLookupGlobal . availName) export_avails ;
191 -- Check whether the entire module is deprecated
192 -- This happens only once per module
193 let { mod_deprecs = checkModDeprec mod_deprec } ;
195 -- Add exports and deprecations to envt
196 let { final_env = tcg_env { tcg_exports = exports,
197 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
198 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
200 -- A module deprecation over-rides the earlier ones
203 -- Report unused names
204 reportUnusedNames final_env ;
206 -- Dump output and return
213 %************************************************************************
215 The interactive interface
217 %************************************************************************
222 -> InteractiveContext
224 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
225 -- The returned [Name] is the same as the input except for
226 -- ExprStmt, in which case the returned [Name] is [itName]
228 -- The returned TypecheckedHsExpr is of type IO [ () ],
229 -- a list of the bound values, coerced to ().
231 tcRnStmt hsc_env ictxt rdr_stmt
232 = initTcPrintErrors hsc_env iNTERACTIVE $
233 setInteractiveContext ictxt $ do {
235 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
236 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
237 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
240 -- The real work is done here
241 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
243 traceTc (text "tcs 1") ;
244 let { -- Make all the bound ids "global" ids, now that
245 -- they're notionally top-level bindings. This is
246 -- important: otherwise when we come to compile an expression
247 -- using these ids later, the byte code generator will consider
248 -- the occurrences to be free rather than global.
249 global_ids = map (globaliseId VanillaGlobal) bound_ids ;
251 -- Update the interactive context
252 rn_env = ic_rn_local_env ictxt ;
253 type_env = ic_type_env ictxt ;
255 bound_names = map idName global_ids ;
256 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
258 -- Remove any shadowed bindings from the type_env;
259 -- they are inaccessible but might, I suppose, cause
260 -- a space leak if we leave them there
261 shadowed = [ n | name <- bound_names,
262 let rdr_name = mkRdrUnqual (nameOccName name),
263 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
265 filtered_type_env = delListFromNameEnv type_env shadowed ;
266 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
268 new_ic = ictxt { ic_rn_local_env = new_rn_env,
269 ic_type_env = new_type_env }
272 dumpOptTcRn Opt_D_dump_tc
273 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
274 text "Typechecked expr" <+> ppr tc_expr]) ;
276 returnM (new_ic, bound_names, tc_expr)
281 Here is the grand plan, implemented in tcUserStmt
283 What you type The IO [HValue] that hscStmt returns
284 ------------- ------------------------------------
285 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
288 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
291 expr (of IO type) ==> expr >>= \ v -> return [coerce HVal v]
292 [NB: result not printed] bindings: [it]
294 expr (of non-IO type, ==> let v = expr in print v >> return [coerce HVal v]
295 result showable) bindings: [it]
297 expr (of non-IO type,
298 result not showable) ==> error
302 ---------------------------
303 tcUserStmt :: LStmt Name -> TcM ([Id], LHsExpr Id)
304 tcUserStmt (L _ (ExprStmt expr _))
305 = newUnique `thenM` \ uniq ->
307 fresh_it = itName uniq
308 the_bind = noLoc $ FunBind (noLoc fresh_it) False
309 [ mkSimpleMatch [] expr placeHolderType ]
311 tryTcLIE_ (do { -- Try this if the other fails
312 traceTc (text "tcs 1b") ;
314 nlLetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive],
315 nlExprStmt (nlHsApp (nlHsVar printName)
318 (do { -- Try this first
319 traceTc (text "tcs 1a") ;
320 tc_stmts [nlBindStmt (nlVarPat fresh_it) expr] })
322 tcUserStmt stmt = tc_stmts [stmt]
324 ---------------------------
326 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
328 ret_ty = mkListTy unitTy ;
329 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
331 names = map unLoc (collectStmtsBinders stmts) ;
333 stmt_ctxt = SC { sc_what = DoExpr,
335 sc_body = check_body,
338 check_rhs rhs rhs_ty = tcCheckRho rhs (mkTyConApp ioTyCon [rhs_ty]) ;
339 check_body body = tcCheckRho body io_ret_ty ;
341 -- mk_return builds the expression
342 -- returnIO @ [()] [coerce () x, .., coerce () z]
344 -- Despite the inconvenience of building the type applications etc,
345 -- this *has* to be done in type-annotated post-typecheck form
346 -- because we are going to return a list of *polymorphic* values
347 -- coerced to type (). If we built a *source* stmt
348 -- return [coerce x, ..., coerce z]
349 -- then the type checker would instantiate x..z, and we wouldn't
350 -- get their *polymorphic* values. (And we'd get ambiguity errs
351 -- if they were overloaded, since they aren't applied to anything.)
352 mk_return ret_id ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
353 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
354 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
357 io_ty = mkTyConApp ioTyCon []
360 -- OK, we're ready to typecheck the stmts
361 traceTc (text "tcs 2") ;
362 ((ids, tc_expr), lie) <- getLIE $ do {
363 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
365 -- Look up the names right in the middle,
366 -- where they will all be in scope
367 ids <- mappM tcLookupId names ;
368 ret_id <- tcLookupId returnIOName ; -- return @ IO
369 return (ids, [nlResultStmt (mk_return ret_id ids)]) } ;
371 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
372 return (ids, noLoc (HsDo DoExpr tc_stmts io_ids io_ret_ty))
375 -- Simplify the context right here, so that we fail
376 -- if there aren't enough instances. Notably, when we see
378 -- we use recoverTc_ to try it <- e
379 -- and then let it = e
380 -- It's the simplify step that rejects the first.
381 traceTc (text "tcs 3") ;
382 const_binds <- tcSimplifyInteractive lie ;
384 -- Build result expression and zonk it
385 let { expr = mkHsLet const_binds tc_expr } ;
386 zonked_expr <- zonkTopLExpr expr ;
387 zonked_ids <- zonkTopBndrs ids ;
389 return (zonked_ids, zonked_expr)
392 combine stmt (ids, stmts) = (ids, stmt:stmts)
396 tcRnExpr just finds the type of an expression
400 -> InteractiveContext
403 tcRnExpr hsc_env ictxt rdr_expr
404 = initTcPrintErrors hsc_env iNTERACTIVE $
405 setInteractiveContext ictxt $ do {
407 (rn_expr, fvs) <- rnLExpr rdr_expr ;
410 -- Now typecheck the expression;
411 -- it might have a rank-2 type (e.g. :t runST)
412 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
413 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
414 tcSimplifyInteractive lie_top ;
416 let { all_expr_ty = mkForAllTys qtvs $
417 mkFunTys (map idType dict_ids) $
419 zonkTcType all_expr_ty
422 smpl_doc = ptext SLIT("main expression")
428 -> InteractiveContext
430 -> IO (Maybe [(IfaceDecl, Fixity)])
431 -- Look up a RdrName and return all the TyThings it might be
432 -- A capitalised RdrName is given to us in the DataName namespace,
433 -- but we want to treat it as *both* a data constructor
434 -- *and* as a type or class constructor;
435 -- hence the call to dataTcOccs, and we return up to two results
436 tcRnThing hsc_env ictxt rdr_name
437 = initTcPrintErrors hsc_env iNTERACTIVE $
438 setInteractiveContext ictxt $ do {
440 -- If the identifier is a constructor (begins with an
441 -- upper-case letter), then we need to consider both
442 -- constructor and type class identifiers.
443 let { rdr_names = dataTcOccs rdr_name } ;
445 -- results :: [(Messages, Maybe Name)]
446 results <- mapM (tryTc . lookupOccRn) rdr_names ;
448 -- The successful lookups will be (Just name)
449 let { (warns_s, good_names) = unzip [ (msgs, name)
450 | (msgs, Just name) <- results] ;
451 errs_s = [msgs | (msgs, Nothing) <- results] } ;
453 -- Fail if nothing good happened, else add warnings
454 if null good_names then
455 -- No lookup succeeded, so
456 -- pick the first error message and report it
457 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
458 -- while the other is "X is not in scope",
459 -- we definitely want the former; but we might pick the latter
460 do { addMessages (head errs_s) ; failM }
461 else -- Add deprecation warnings
462 mapM_ addMessages warns_s ;
464 -- And lookup up the entities
465 mapM do_one good_names
468 do_one name = do { thing <- tcLookupGlobal name
469 ; fixity <- lookupFixityRn name
470 ; return (toIfaceDecl ictxt thing, fixity) }
472 toIfaceDecl :: InteractiveContext -> TyThing -> IfaceDecl
473 toIfaceDecl ictxt thing
474 = tyThingToIfaceDecl True {- Discard IdInfo -} emptyNameSet {- Show data cons -}
477 unqual = icPrintUnqual ictxt
478 ext_nm n | unqual n = LocalTop (nameOccName n) -- What a hack
479 | otherwise = ExtPkg (nameModuleName n) (nameOccName n)
484 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
485 setInteractiveContext icxt thing_inside
486 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
487 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
488 tcg_type_env = ic_type_env icxt}) $
489 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
494 %************************************************************************
496 Type-checking external-core modules
498 %************************************************************************
501 tcRnExtCore :: HscEnv
503 -> IO (Messages, Maybe ModGuts)
504 -- Nothing => some error occurred
506 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
507 -- The decls are IfaceDecls; all names are original names
508 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
510 initTc hsc_env this_mod $ do {
512 let { ldecls = map noLoc decls } ;
514 -- Deal with the type declarations; first bring their stuff
515 -- into scope, then rname them, then type check them
516 (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup ldecls) ;
518 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
519 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
522 rn_decls <- rnTyClDecls ldecls ;
525 -- Dump trace of renaming part
526 rnDump (ppr rn_decls) ;
528 -- Typecheck them all together so that
529 -- any mutually recursive types are done right
530 tcg_env <- checkNoErrs (tcTyAndClassDecls rn_decls) ;
531 -- Make the new type env available to stuff slurped from interface files
533 setGblEnv tcg_env $ do {
535 -- Now the core bindings
536 core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;
540 bndrs = bindersOfBinds core_binds ;
541 my_exports = mkNameSet (map idName bndrs) ;
542 -- ToDo: export the data types also?
544 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
546 mod_guts = ModGuts { mg_module = this_mod,
547 mg_usages = [], -- ToDo: compute usage
548 mg_dir_imps = [], -- ??
549 mg_deps = noDependencies, -- ??
550 mg_exports = my_exports,
551 mg_types = final_type_env,
552 mg_insts = tcg_insts tcg_env,
554 mg_binds = core_binds,
557 mg_rdr_env = emptyGlobalRdrEnv,
558 mg_fix_env = emptyFixityEnv,
559 mg_deprecs = NoDeprecs,
563 tcCoreDump mod_guts ;
568 mkFakeGroup decls -- Rather clumsy; lots of unused fields
569 = HsGroup { hs_tyclds = decls, -- This is the one we want
570 hs_valds = [], hs_fords = [],
571 hs_instds = [], hs_fixds = [], hs_depds = [],
572 hs_ruleds = [], hs_defds = [] }
576 %************************************************************************
578 Type-checking the top level of a module
580 %************************************************************************
583 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
584 -- Returns the variables free in the decls
585 -- Reason: solely to report unused imports and bindings
587 = do { -- Do all the declarations
588 (tc_envs, lie) <- getLIE (tc_rn_src_decls decls) ;
590 -- tcSimplifyTop deals with constant or ambiguous InstIds.
591 -- How could there be ambiguous ones? They can only arise if a
592 -- top-level decl falls under the monomorphism
593 -- restriction, and no subsequent decl instantiates its
594 -- type. (Usually, ambiguous type variables are resolved
595 -- during the generalisation step.)
596 traceTc (text "Tc8") ;
597 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
598 -- Setting the global env exposes the instances to tcSimplifyTop
599 -- Setting the local env exposes the local Ids to tcSimplifyTop,
600 -- so that we get better error messages (monomorphism restriction)
602 -- Backsubstitution. This must be done last.
603 -- Even tcSimplifyTop may do some unification.
604 traceTc (text "Tc9") ;
605 let { (tcg_env, _) = tc_envs ;
606 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
607 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
609 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
612 let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
614 -- Make the new type env available to stuff slurped from interface files
615 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
617 return (tcg_env { tcg_type_env = final_type_env,
618 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' })
621 tc_rn_src_decls :: [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
622 -- Loops around dealing with each top level inter-splice group
623 -- in turn, until it's dealt with the entire module
625 = do { let { (first_group, group_tail) = findSplice ds } ;
626 -- If ds is [] we get ([], Nothing)
628 -- Type check the decls up to, but not including, the first splice
629 tc_envs@(tcg_env,tcl_env) <- tcRnGroup first_group ;
631 -- Bale out if errors; for example, error recovery when checking
632 -- the RHS of 'main' can mean that 'main' is not in the envt for
633 -- the subsequent checkMain test
638 -- If there is no splice, we're nearly done
640 Nothing -> do { -- Last thing: check for `main'
641 tcg_env <- checkMain ;
642 return (tcg_env, tcl_env)
645 -- If there's a splice, we must carry on
646 Just (SpliceDecl splice_expr, rest_ds) -> do {
648 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
651 -- Rename the splice expression, and get its supporting decls
652 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
653 failIfErrsM ; -- Don't typecheck if renaming failed
655 -- Execute the splice
656 spliced_decls <- tcSpliceDecls rn_splice_expr ;
658 -- Glue them on the front of the remaining decls and loop
659 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
660 tc_rn_src_decls (spliced_decls ++ rest_ds)
666 %************************************************************************
668 Type-checking the top level of a module
670 %************************************************************************
672 tcRnGroup takes a bunch of top-level source-code declarations, and
674 * gets supporting declarations from interface files
677 * and augments the TcGblEnv with the results
679 In Template Haskell it may be called repeatedly for each group of
680 declarations. It expects there to be an incoming TcGblEnv in the
681 monad; it augments it and returns the new TcGblEnv.
684 tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
685 -- Returns the variables free in the decls, for unused-binding reporting
687 = do { -- Rename the declarations
688 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
689 setGblEnv tcg_env $ do {
691 -- Typecheck the declarations
692 tcTopSrcDecls rn_decls
695 ------------------------------------------------
696 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
698 = do { -- Bring top level binders into scope
699 (rdr_env, imports) <- importsFromLocalDecls group ;
700 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
701 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
704 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
705 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
707 -- Rename the source decls
708 (tcg_env, rn_decls) <- rnSrcDecls group ;
711 -- Dump trace of renaming part
712 rnDump (ppr rn_decls) ;
714 return (tcg_env, rn_decls)
717 ------------------------------------------------
718 tcTopSrcDecls :: HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
720 (HsGroup { hs_tyclds = tycl_decls,
721 hs_instds = inst_decls,
722 hs_fords = foreign_decls,
723 hs_defds = default_decls,
724 hs_ruleds = rule_decls,
725 hs_valds = val_binds })
726 = do { -- Type-check the type and class decls, and all imported decls
727 -- The latter come in via tycl_decls
728 traceTc (text "Tc2") ;
730 tcg_env <- checkNoErrs (tcTyAndClassDecls tycl_decls) ;
731 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
732 -- an error we'd better stop now, to avoid a cascade
734 -- Make these type and class decls available to stuff slurped from interface files
735 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
738 setGblEnv tcg_env $ do {
739 -- Source-language instances, including derivings,
740 -- and import the supporting declarations
741 traceTc (text "Tc3") ;
742 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
743 setGblEnv tcg_env $ do {
745 -- Foreign import declarations next. No zonking necessary
746 -- here; we can tuck them straight into the global environment.
747 traceTc (text "Tc4") ;
748 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
749 tcExtendGlobalValEnv fi_ids $ do {
751 -- Default declarations
752 traceTc (text "Tc4a") ;
753 default_tys <- tcDefaults default_decls ;
754 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
756 -- Value declarations next
757 -- We also typecheck any extra binds that came out
758 -- of the "deriving" process (deriv_binds)
759 traceTc (text "Tc5") ;
760 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
761 setLclTypeEnv lcl_env $ do {
763 -- Second pass over class and instance declarations,
764 traceTc (text "Tc6") ;
765 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
766 showLIE (text "after instDecls2") ;
769 -- They need to be zonked, so we return them
770 traceTc (text "Tc7") ;
771 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
774 rules <- tcRules rule_decls ;
777 traceTc (text "Tc7a") ;
778 tcg_env <- getGblEnv ;
779 let { all_binds = tc_val_binds `unionBags`
780 inst_binds `unionBags`
783 -- Extend the GblEnv with the (as yet un-zonked)
784 -- bindings, rules, foreign decls
785 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
786 tcg_rules = tcg_rules tcg_env ++ rules,
787 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
788 return (tcg_env', lcl_env)
793 %*********************************************************
795 mkGlobalContext: make up an interactive context
797 Used for initialising the lexical environment
798 of the interactive read-eval-print loop
800 %*********************************************************
804 mkExportEnv :: HscEnv -> [ModuleName] -- Expose these modules' exports only
807 mkExportEnv hsc_env exports
808 = do { mb_envs <- initTcPrintErrors hsc_env iNTERACTIVE $
809 mappM getModuleExports exports
811 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
812 Nothing -> return emptyGlobalRdrEnv
813 -- Some error; initTc will have printed it
816 getModuleExports :: ModuleName -> TcM GlobalRdrEnv
818 = do { iface <- load_iface mod
819 ; avails <- exportsToAvails (mi_exports iface)
820 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
821 | avail <- avails, name <- availNames avail ] }
822 ; returnM (mkGlobalRdrEnv gres) }
824 vanillaProv :: ModuleName -> Provenance
825 -- We're building a GlobalRdrEnv as if the user imported
826 -- all the specified modules into the global interactive module
827 vanillaProv mod = Imported [ImportSpec mod mod False
828 (srcLocSpan interactiveSrcLoc)] False
834 -> InteractiveContext
835 -> ModuleName -- Module to inspect
836 -> Bool -- Grab just the exports, or the whole toplev
837 -> IO (Maybe [IfaceDecl])
839 getModuleContents hsc_env ictxt mod exports_only
840 = initTcPrintErrors hsc_env iNTERACTIVE (get_mod_contents exports_only)
842 get_mod_contents exports_only
843 | not exports_only -- We want the whole top-level type env
844 -- so it had better be a home module
846 ; case lookupModuleEnvByName hpt mod of
847 Just mod_info -> return (map (toIfaceDecl ictxt) $
850 md_types (hm_details mod_info))
851 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
852 -- This is a system error; the module should be in the HPT
855 | otherwise -- Want the exports only
856 = do { iface <- load_iface mod
857 ; avails <- exportsToAvails (mi_exports iface)
858 ; mappM get_decl avails
862 = do { thing <- tcLookupGlobal (availName avail)
863 ; return (filter_decl (availOccs avail) (toIfaceDecl ictxt thing)) }
865 ---------------------
866 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
867 = decl { ifSigs = filter (keep_sig occs) sigs }
868 filter_decl occs decl@(IfaceData {ifCons = IfDataTyCon cons})
869 = decl { ifCons = IfDataTyCon (filter (keep_con occs) cons) }
870 filter_decl occs decl@(IfaceData {ifCons = IfNewTyCon con})
871 | keep_con occs con = decl
872 | otherwise = decl {ifCons = IfAbstractTyCon} -- Hmm?
873 filter_decl occs decl
876 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
877 keep_con occs (IfaceConDecl occ _ _ _ _ _) = occ `elem` occs
879 availOccs avail = map nameOccName (availNames avail)
881 wantToSee (AnId id) = not (isImplicitId id)
882 wantToSee (ADataCon _) = False -- They'll come via their TyCon
885 ---------------------
886 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
888 doc = ptext SLIT("context for compiling statements")
890 ---------------------
891 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
896 %************************************************************************
900 %************************************************************************
904 = do { ghci_mode <- getGhciMode ;
905 tcg_env <- getGblEnv ;
907 mb_main_mod <- readMutVar v_MainModIs ;
908 mb_main_fn <- readMutVar v_MainFunIs ;
909 let { main_mod = case mb_main_mod of {
910 Just mod -> mkModuleName mod ;
911 Nothing -> mAIN_Name } ;
912 main_fn = case mb_main_fn of {
913 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
914 Nothing -> main_RDR_Unqual } } ;
916 check_main ghci_mode tcg_env main_mod main_fn
920 check_main ghci_mode tcg_env main_mod main_fn
921 -- If we are in module Main, check that 'main' is defined.
922 -- It may be imported from another module!
924 -- ToDo: We have to return the main_name separately, because it's a
925 -- bona fide 'use', and should be recorded as such, but the others
928 -- Blimey: a whole page of code to do this...
929 | mod_name /= main_mod
933 = addErrCtxt mainCtxt $
934 do { mb_main <- lookupSrcOcc_maybe main_fn
935 -- Check that 'main' is in scope
936 -- It might be imported from another module!
938 Nothing -> do { complain_no_main
941 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
942 -- :Main.main :: IO () = runIO main
944 ; (main_expr, ty) <- addSrcSpan (srcLocSpan (getSrcLoc main_name)) $
947 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
948 main_bind = noLoc (VarBind root_main_id main_expr) }
950 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
952 tcg_dus = tcg_dus tcg_env
953 `plusDU` usesOnly (unitFV main_name)
957 mod_name = moduleName (tcg_mod tcg_env)
959 complain_no_main | ghci_mode == Interactive = return ()
960 | otherwise = failWithTc noMainMsg
961 -- In interactive mode, don't worry about the absence of 'main'
962 -- In other modes, fail altogether, so that we don't go on
963 -- and complain a second time when processing the export list.
965 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
966 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
967 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
971 %************************************************************************
975 %************************************************************************
978 rnDump :: SDoc -> TcRn ()
979 -- Dump, with a banner, if -ddump-rn
980 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
982 tcDump :: TcGblEnv -> TcRn ()
984 = do { dflags <- getDOpts ;
986 -- Dump short output if -ddump-types or -ddump-tc
987 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
988 (dumpTcRn short_dump) ;
990 -- Dump bindings if -ddump-tc
991 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
994 short_dump = pprTcGblEnv env
995 full_dump = ppr (tcg_binds env)
996 -- NB: foreign x-d's have undefined's in their types;
997 -- hence can't show the tc_fords
1000 = do { dflags <- getDOpts ;
1001 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1002 (dumpTcRn (pprModGuts mod_guts)) ;
1004 -- Dump bindings if -ddump-tc
1005 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1007 full_dump = pprCoreBindings (mg_binds mod_guts)
1009 -- It's unpleasant having both pprModGuts and pprModDetails here
1010 pprTcGblEnv :: TcGblEnv -> SDoc
1011 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1012 tcg_insts = dfun_ids,
1014 tcg_imports = imports })
1015 = vcat [ ppr_types dfun_ids type_env
1016 , ppr_insts dfun_ids
1017 , vcat (map ppr rules)
1018 , ppr_gen_tycons (typeEnvTyCons type_env)
1019 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1020 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1022 pprModGuts :: ModGuts -> SDoc
1023 pprModGuts (ModGuts { mg_types = type_env,
1025 = vcat [ ppr_types [] type_env,
1029 ppr_types :: [Var] -> TypeEnv -> SDoc
1030 ppr_types dfun_ids type_env
1031 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1033 ids = [id | id <- typeEnvIds type_env, want_sig id]
1034 want_sig id | opt_PprStyle_Debug = True
1035 | otherwise = isLocalId id &&
1036 isExternalName (idName id) &&
1037 not (id `elem` dfun_ids)
1038 -- isLocalId ignores data constructors, records selectors etc.
1039 -- The isExternalName ignores local dictionary and method bindings
1040 -- that the type checker has invented. Top-level user-defined things
1041 -- have External names.
1043 ppr_insts :: [Var] -> SDoc
1044 ppr_insts [] = empty
1045 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1047 ppr_sigs :: [Var] -> SDoc
1049 -- Print type signatures; sort by OccName
1050 = vcat (map ppr_sig (sortLt lt_sig ids))
1052 lt_sig id1 id2 = getOccName id1 < getOccName id2
1053 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1055 ppr_rules :: [IdCoreRule] -> SDoc
1056 ppr_rules [] = empty
1057 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1058 nest 4 (pprIdRules rs),
1061 ppr_gen_tycons [] = empty
1062 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1063 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]