2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
9 mkExportEnv, getModuleContents, tcRnStmt, tcRnThing, tcRnExpr,
13 tcRnIface, tcRnExtCore
16 #include "HsVersions.h"
19 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
22 import CmdLineOpts ( DynFlag(..), opt_PprStyle_Debug, dopt )
23 import DriverState ( v_MainModIs, v_MainFunIs )
24 import HsSyn ( HsModule(..), HsBinds(..), MonoBinds(..), HsExpr(..),
25 HsGroup(..), SpliceDecl(..), HsExtCore(..),
28 import RdrHsSyn ( RdrNameHsModule, RdrNameHsDecl,
29 findSplice, main_RDR_Unqual )
31 import PrelNames ( runIOName, rootMainName, mAIN_Name )
32 import RdrName ( RdrName, mkRdrUnqual, emptyGlobalRdrEnv,
34 import TcHsSyn ( zonkTopDecls )
35 import TcExpr ( tcInferRho )
37 import TcType ( tidyTopType )
38 import Inst ( showLIE )
39 import TcBinds ( tcTopBinds )
40 import TcDefaults ( tcDefaults )
41 import TcEnv ( tcExtendGlobalValEnv, tcLookupGlobal )
42 import TcRules ( tcRules )
43 import TcForeign ( tcForeignImports, tcForeignExports )
44 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
45 import TcIface ( typecheckIface, tcExtCoreBindings )
46 import TcSimplify ( tcSimplifyTop )
47 import TcTyClsDecls ( tcTyAndClassDecls )
48 import LoadIface ( loadOrphanModules )
49 import RnNames ( importsFromLocalDecls, rnImports, exportsFromAvail,
51 import RnEnv ( lookupSrcOcc_maybe )
52 import RnSource ( rnSrcDecls, rnTyClDecls, checkModDeprec )
53 import PprCore ( pprIdRules, pprCoreBindings )
54 import CoreSyn ( IdCoreRule, bindersOfBinds )
55 import ErrUtils ( mkDumpDoc, showPass )
56 import Id ( mkLocalId, isLocalId, idName, idType, setIdLocalExported )
58 import Module ( mkHomeModule, mkModuleName, moduleName, moduleEnvElts )
59 import OccName ( mkVarOcc )
60 import Name ( Name, isExternalName, getSrcLoc, getOccName )
62 import TyCon ( tyConHasGenerics )
64 import HscTypes ( ModIface, ModDetails(..), ModGuts(..),
65 HscEnv(..), ModIface(..), ModDetails(..),
66 GhciMode(..), noDependencies,
67 Deprecs( NoDeprecs ), plusDeprecs,
68 GenAvailInfo(Avail), availsToNameSet, availName,
69 ForeignStubs(NoStubs), TypeEnv, typeEnvTyCons,
70 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
74 import HsSyn ( HsStmtContext(..),
75 Stmt(..), Pat(VarPat),
76 collectStmtsBinders, mkSimpleMatch, placeHolderType )
77 import RdrHsSyn ( RdrNameHsExpr, RdrNameStmt )
78 import RdrName ( GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
79 Provenance(..), ImportSpec(..),
80 lookupLocalRdrEnv, extendLocalRdrEnv )
81 import RnHsSyn ( RenamedStmt )
82 import RnSource ( addTcgDUs )
83 import TcHsSyn ( TypecheckedHsExpr, mkHsLet, zonkTopExpr, zonkTopBndrs )
84 import TcExpr ( tcCheckRho )
85 import TcMType ( zonkTcType )
86 import TcMatches ( tcStmtsAndThen, TcStmtCtxt(..) )
87 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
88 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType )
89 import TcEnv ( tcLookupTyCon, tcLookupId )
90 import TyCon ( DataConDetails(..) )
91 import Inst ( tcStdSyntaxName )
92 import RnExpr ( rnStmts, rnExpr )
93 import RnNames ( exportsToAvails )
94 import LoadIface ( loadSysInterface )
95 import IfaceSyn ( IfaceDecl(..), IfaceClassOp(..), IfaceConDecl(..), IfaceExtName(..),
97 import IfaceEnv ( tcIfaceGlobal )
98 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
99 import Id ( Id, isImplicitId )
100 import MkId ( unsafeCoerceId )
101 import TysWiredIn ( mkListTy, unitTy )
102 import IdInfo ( GlobalIdDetails(..) )
103 import SrcLoc ( interactiveSrcLoc )
104 import Var ( setGlobalIdDetails )
105 import Name ( nameOccName, nameModuleName )
106 import NameEnv ( delListFromNameEnv )
107 import PrelNames ( iNTERACTIVE, ioTyConName, printName, monadNames, itName, returnIOName )
108 import Module ( ModuleName, lookupModuleEnvByName )
109 import HscTypes ( InteractiveContext(..),
110 HomeModInfo(..), typeEnvElts,
111 TyThing(..), availNames, icPrintUnqual )
112 import BasicTypes ( RecFlag(..), Fixity )
113 import Panic ( ghcError, GhcException(..) )
116 import FastString ( mkFastString )
117 import Util ( sortLt )
122 %************************************************************************
124 Typecheck and rename a module
126 %************************************************************************
132 -> IO (Maybe TcGblEnv)
135 (HsModule maybe_mod exports import_decls local_decls mod_deprec loc)
136 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
138 let { this_mod = case maybe_mod of
139 Nothing -> mkHomeModule mAIN_Name -- 'module M where' is omitted
140 Just mod -> mod } ; -- The normal case
142 initTc hsc_env this_mod $ addSrcLoc loc $
143 do { -- Deal with imports; sets tcg_rdr_env, tcg_imports
144 (rdr_env, imports) <- rnImports import_decls ;
145 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
146 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
148 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
149 -- Fail if there are any errors so far
150 -- The error printing (if needed) takes advantage
151 -- of the tcg_env we have now set
154 -- Load any orphan-module interfaces, so that
155 -- their rules and instance decls will be found
156 loadOrphanModules (imp_orphs imports) ;
158 traceRn (text "rn1a") ;
159 -- Rename and type check the declarations
160 tcg_env <- tcRnSrcDecls local_decls ;
161 setGblEnv tcg_env $ do {
163 traceRn (text "rn3") ;
165 -- Process the export list
166 export_avails <- exportsFromAvail maybe_mod exports ;
168 -- Get any supporting decls for the exports that have not already
169 -- been sucked in for the declarations in the body of the module.
170 -- (This can happen if something is imported only to be re-exported.)
172 -- Importing these supporting declarations is required
173 -- *only* to gether usage information
174 -- (see comments with MkIface.mkImportInfo for why)
175 -- We don't need the results, but sucking them in may side-effect
176 -- the ExternalPackageState, apart from recording usage
177 mappM (tcLookupGlobal . availName) export_avails ;
179 -- Check whether the entire module is deprecated
180 -- This happens only once per module
181 let { mod_deprecs = checkModDeprec mod_deprec } ;
183 -- Add exports and deprecations to envt
184 let { export_fvs = availsToNameSet export_avails ;
185 final_env = tcg_env { tcg_exports = export_avails,
186 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly export_fvs,
187 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
189 -- A module deprecation over-rides the earlier ones
192 -- Report unused names
193 reportUnusedNames final_env ;
195 -- Dump output and return
202 %*********************************************************
204 \subsection{Closing up the interface decls}
206 %*********************************************************
208 Suppose we discover we don't need to recompile. Then we start from the
209 IfaceDecls in the ModIface, and fluff them up by sucking in all the decls they need.
213 -> ModIface -- Get the decls from here
215 tcRnIface hsc_env iface
216 = initIfaceIO hsc_env (typecheckIface iface)
220 %************************************************************************
222 The interactive interface
224 %************************************************************************
229 -> InteractiveContext
231 -> IO (Maybe (InteractiveContext, [Name], TypecheckedHsExpr))
232 -- The returned [Name] is the same as the input except for
233 -- ExprStmt, in which case the returned [Name] is [itName]
235 -- The returned TypecheckedHsExpr is of type IO [ () ],
236 -- a list of the bound values, coerced to ().
238 tcRnStmt hsc_env ictxt rdr_stmt
239 = initTc hsc_env iNTERACTIVE $
240 setInteractiveContext ictxt $ do {
242 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
243 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
244 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
247 -- The real work is done here
248 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
250 traceTc (text "tcs 1") ;
251 let { -- Make all the bound ids "global" ids, now that
252 -- they're notionally top-level bindings. This is
253 -- important: otherwise when we come to compile an expression
254 -- using these ids later, the byte code generator will consider
255 -- the occurrences to be free rather than global.
256 global_ids = map globaliseId bound_ids ;
257 globaliseId id = setGlobalIdDetails id VanillaGlobal ;
259 -- Update the interactive context
260 rn_env = ic_rn_local_env ictxt ;
261 type_env = ic_type_env ictxt ;
263 bound_names = map idName global_ids ;
264 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
266 -- Remove any shadowed bindings from the type_env;
267 -- they are inaccessible but might, I suppose, cause
268 -- a space leak if we leave them there
269 shadowed = [ n | name <- bound_names,
270 let rdr_name = mkRdrUnqual (nameOccName name),
271 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
273 filtered_type_env = delListFromNameEnv type_env shadowed ;
274 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
276 new_ic = ictxt { ic_rn_local_env = new_rn_env,
277 ic_type_env = new_type_env }
280 dumpOptTcRn Opt_D_dump_tc
281 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
282 text "Typechecked expr" <+> ppr tc_expr]) ;
284 returnM (new_ic, bound_names, tc_expr)
289 Here is the grand plan, implemented in tcUserStmt
291 What you type The IO [HValue] that hscStmt returns
292 ------------- ------------------------------------
293 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
296 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
299 expr (of IO type) ==> expr >>= \ v -> return [coerce HVal v]
300 [NB: result not printed] bindings: [it]
302 expr (of non-IO type, ==> let v = expr in print v >> return [coerce HVal v]
303 result showable) bindings: [it]
305 expr (of non-IO type,
306 result not showable) ==> error
310 ---------------------------
311 tcUserStmt :: RenamedStmt -> TcM ([Id], TypecheckedHsExpr)
312 tcUserStmt (ExprStmt expr _ loc)
313 = newUnique `thenM` \ uniq ->
315 fresh_it = itName uniq
316 the_bind = FunMonoBind fresh_it False
317 [ mkSimpleMatch [] expr placeHolderType loc ] loc
319 tryTcLIE_ (do { -- Try this if the other fails
320 traceTc (text "tcs 1b") ;
322 LetStmt (MonoBind the_bind [] NonRecursive),
323 ExprStmt (HsApp (HsVar printName) (HsVar fresh_it))
324 placeHolderType loc] })
325 (do { -- Try this first
326 traceTc (text "tcs 1a") ;
327 tc_stmts [BindStmt (VarPat fresh_it) expr loc] })
329 tcUserStmt stmt = tc_stmts [stmt]
331 ---------------------------
333 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
335 ret_ty = mkListTy unitTy ;
336 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
338 names = collectStmtsBinders stmts ;
340 stmt_ctxt = SC { sc_what = DoExpr,
342 sc_body = check_body,
345 check_rhs rhs rhs_ty = tcCheckRho rhs (mkTyConApp ioTyCon [rhs_ty]) ;
346 check_body body = tcCheckRho body io_ret_ty ;
348 -- mk_return builds the expression
349 -- returnIO @ [()] [coerce () x, .., coerce () z]
351 -- Despite the inconvenience of building the type applications etc,
352 -- this *has* to be done in type-annotated post-typecheck form
353 -- because we are going to return a list of *polymorphic* values
354 -- coerced to type (). If we built a *source* stmt
355 -- return [coerce x, ..., coerce z]
356 -- then the type checker would instantiate x..z, and we wouldn't
357 -- get their *polymorphic* values. (And we'd get ambiguity errs
358 -- if they were overloaded, since they aren't applied to anything.)
359 mk_return ret_id ids = HsApp (TyApp (HsVar ret_id) [ret_ty])
360 (ExplicitList unitTy (map mk_item ids)) ;
361 mk_item id = HsApp (TyApp (HsVar unsafeCoerceId) [idType id, unitTy])
364 io_ty = mkTyConApp ioTyCon []
367 -- OK, we're ready to typecheck the stmts
368 traceTc (text "tcs 2") ;
369 ((ids, tc_expr), lie) <- getLIE $ do {
370 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
372 -- Look up the names right in the middle,
373 -- where they will all be in scope
374 ids <- mappM tcLookupId names ;
375 ret_id <- tcLookupId returnIOName ; -- return @ IO
376 return (ids, [ResultStmt (mk_return ret_id ids) interactiveSrcLoc]) } ;
378 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
379 return (ids, HsDo DoExpr tc_stmts io_ids io_ret_ty interactiveSrcLoc)
382 -- Simplify the context right here, so that we fail
383 -- if there aren't enough instances. Notably, when we see
385 -- we use recoverTc_ to try it <- e
386 -- and then let it = e
387 -- It's the simplify step that rejects the first.
388 traceTc (text "tcs 3") ;
389 const_binds <- tcSimplifyInteractive lie ;
391 -- Build result expression and zonk it
392 let { expr = mkHsLet const_binds tc_expr } ;
393 zonked_expr <- zonkTopExpr expr ;
394 zonked_ids <- zonkTopBndrs ids ;
396 return (zonked_ids, zonked_expr)
399 combine stmt (ids, stmts) = (ids, stmt:stmts)
403 tcRnExpr just finds the type of an expression
407 -> InteractiveContext
410 tcRnExpr hsc_env ictxt rdr_expr
411 = initTc hsc_env iNTERACTIVE $
412 setInteractiveContext ictxt $ do {
414 (rn_expr, fvs) <- rnExpr rdr_expr ;
417 -- Now typecheck the expression;
418 -- it might have a rank-2 type (e.g. :t runST)
419 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
420 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
421 tcSimplifyInteractive lie_top ;
423 let { all_expr_ty = mkForAllTys qtvs $
424 mkFunTys (map idType dict_ids) $
426 zonkTcType all_expr_ty
429 smpl_doc = ptext SLIT("main expression")
435 -> InteractiveContext
437 -> IO (Maybe [(IfaceDecl, Fixity)])
438 -- Look up a RdrName and return all the TyThings it might be
439 -- A capitalised RdrName is given to us in the DataName namespace,
440 -- but we want to treat it as *both* a data constructor
441 -- *and* as a type or class constructor;
442 -- hence the call to dataTcOccs, and we return up to two results
443 tcRnThing hsc_env ictxt rdr_name
444 = initTc hsc_env iNTERACTIVE $
445 setInteractiveContext ictxt $ do {
447 -- If the identifier is a constructor (begins with an
448 -- upper-case letter), then we need to consider both
449 -- constructor and type class identifiers.
450 let { rdr_names = dataTcOccs rdr_name } ;
452 -- results :: [(Messages, Maybe Name)]
453 results <- mapM (tryTc . lookupOccRn) rdr_names ;
455 -- The successful lookups will be (Just name)
456 let { (warns_s, good_names) = unzip [ (msgs, name)
457 | (msgs, Just name) <- results] ;
458 errs_s = [msgs | (msgs, Nothing) <- results] } ;
460 -- Fail if nothing good happened, else add warnings
461 if null good_names then
462 -- No lookup succeeded, so
463 -- pick the first error message and report it
464 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
465 -- while the other is "X is not in scope",
466 -- we definitely want the former; but we might pick the latter
467 do { addMessages (head errs_s) ; failM }
468 else -- Add deprecation warnings
469 mapM_ addMessages warns_s ;
471 -- And lookup up the entities
472 mapM do_one good_names
475 do_one name = do { thing <- tcLookupGlobal name
476 ; fixity <- lookupFixityRn name
477 ; return (toIfaceDecl ictxt thing, fixity) }
479 toIfaceDecl :: InteractiveContext -> TyThing -> IfaceDecl
480 toIfaceDecl ictxt thing
481 = tyThingToIfaceDecl True {- Discard IdInfo -} ext_nm thing
483 unqual = icPrintUnqual ictxt
484 ext_nm n | unqual n = LocalTop (nameOccName n) -- What a hack
485 | otherwise = ExtPkg (nameModuleName n) (nameOccName n)
490 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
491 setInteractiveContext icxt thing_inside
492 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
493 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
494 tcg_type_env = ic_type_env icxt}) $
495 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
500 %************************************************************************
502 Type-checking external-core modules
504 %************************************************************************
507 tcRnExtCore :: HscEnv
509 -> IO (Maybe ModGuts)
510 -- Nothing => some error occurred
512 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
513 -- The decls are IfaceDecls; all names are original names
514 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
516 initTc hsc_env this_mod $ do {
518 -- Deal with the type declarations; first bring their stuff
519 -- into scope, then rname them, then type check them
520 (rdr_env, imports) <- importsFromLocalDecls $
521 HsGroup { hs_tyclds = decls, hs_valds = EmptyBinds, hs_fords = [] } ;
522 -- Rather clumsy; lots of unused fields
524 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
525 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
528 rn_decls <- rnTyClDecls decls ;
531 -- Dump trace of renaming part
532 rnDump (ppr rn_decls) ;
534 -- Typecheck them all together so that
535 -- any mutually recursive types are done right
536 tcg_env <- checkNoErrs (tcTyAndClassDecls rn_decls) ;
537 -- Make the new type env available to stuff slurped from interface files
539 setGblEnv tcg_env $ do {
541 -- Now the core bindings
542 core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;
546 bndrs = bindersOfBinds core_binds ;
547 my_exports = map (Avail . idName) bndrs ;
548 -- ToDo: export the data types also?
550 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
552 mod_guts = ModGuts { mg_module = this_mod,
553 mg_usages = [], -- ToDo: compute usage
554 mg_dir_imps = [], -- ??
555 mg_deps = noDependencies, -- ??
556 mg_exports = my_exports,
557 mg_types = final_type_env,
558 mg_insts = tcg_insts tcg_env,
560 mg_binds = core_binds,
563 mg_rdr_env = emptyGlobalRdrEnv,
564 mg_fix_env = emptyFixityEnv,
565 mg_deprecs = NoDeprecs,
569 tcCoreDump mod_guts ;
576 %************************************************************************
578 Type-checking the top level of a module
580 %************************************************************************
583 tcRnSrcDecls :: [RdrNameHsDecl] -> 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 `andMonoBinds` 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 :: [RdrNameHsDecl] -> 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 splice_loc, 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) <- addSrcLoc splice_loc $
654 -- Execute the splice
655 spliced_decls <- tcSpliceDecls rn_splice_expr ;
657 -- Glue them on the front of the remaining decls and loop
658 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
659 tc_rn_src_decls (spliced_decls ++ rest_ds)
665 %************************************************************************
667 Type-checking the top level of a module
669 %************************************************************************
671 tcRnGroup takes a bunch of top-level source-code declarations, and
673 * gets supporting declarations from interface files
676 * and augments the TcGblEnv with the results
678 In Template Haskell it may be called repeatedly for each group of
679 declarations. It expects there to be an incoming TcGblEnv in the
680 monad; it augments it and returns the new TcGblEnv.
683 tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
684 -- Returns the variables free in the decls, for unused-binding reporting
686 = do { -- Rename the declarations
687 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
688 setGblEnv tcg_env $ do {
690 -- Typecheck the declarations
691 tcTopSrcDecls rn_decls
694 ------------------------------------------------
695 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
697 = do { -- Bring top level binders into scope
698 (rdr_env, imports) <- importsFromLocalDecls group ;
699 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
700 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
703 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
705 -- Rename the source decls
706 (tcg_env, rn_decls) <- rnSrcDecls group ;
709 -- Dump trace of renaming part
710 rnDump (ppr rn_decls) ;
712 return (tcg_env, rn_decls)
715 ------------------------------------------------
716 tcTopSrcDecls :: HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
718 (HsGroup { hs_tyclds = tycl_decls,
719 hs_instds = inst_decls,
720 hs_fords = foreign_decls,
721 hs_defds = default_decls,
722 hs_ruleds = rule_decls,
723 hs_valds = val_binds })
724 = do { -- Type-check the type and class decls, and all imported decls
725 -- The latter come in via tycl_decls
726 traceTc (text "Tc2") ;
728 tcg_env <- checkNoErrs (tcTyAndClassDecls tycl_decls) ;
729 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
730 -- an error we'd better stop now, to avoid a cascade
732 -- Make these type and class decls available to stuff slurped from interface files
733 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
736 setGblEnv tcg_env $ do {
737 -- Source-language instances, including derivings,
738 -- and import the supporting declarations
739 traceTc (text "Tc3") ;
740 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
741 setGblEnv tcg_env $ do {
743 -- Foreign import declarations next. No zonking necessary
744 -- here; we can tuck them straight into the global environment.
745 traceTc (text "Tc4") ;
746 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
747 tcExtendGlobalValEnv fi_ids $ do {
749 -- Default declarations
750 traceTc (text "Tc4a") ;
751 default_tys <- tcDefaults default_decls ;
752 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
754 -- Value declarations next
755 -- We also typecheck any extra binds that came out
756 -- of the "deriving" process (deriv_binds)
757 traceTc (text "Tc5") ;
758 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds `ThenBinds` deriv_binds) ;
759 setLclTypeEnv lcl_env $ do {
761 -- Second pass over class and instance declarations,
762 traceTc (text "Tc6") ;
763 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
764 showLIE (text "after instDecls2") ;
767 -- They need to be zonked, so we return them
768 traceTc (text "Tc7") ;
769 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
772 rules <- tcRules rule_decls ;
775 traceTc (text "Tc7a") ;
776 tcg_env <- getGblEnv ;
777 let { all_binds = tc_val_binds `AndMonoBinds`
778 inst_binds `AndMonoBinds`
781 -- Extend the GblEnv with the (as yet un-zonked)
782 -- bindings, rules, foreign decls
783 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `andMonoBinds` all_binds,
784 tcg_rules = tcg_rules tcg_env ++ rules,
785 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
786 return (tcg_env', lcl_env)
791 %*********************************************************
793 mkGlobalContext: make up an interactive context
795 Used for initialising the lexical environment
796 of the interactive read-eval-print loop
798 %*********************************************************
802 mkExportEnv :: HscEnv -> [ModuleName] -- Expose these modules' exports only
805 mkExportEnv hsc_env exports
806 = initIfaceIO hsc_env $ do {
807 export_envs <- mappM getModuleExports exports ;
808 returnM (foldr plusGlobalRdrEnv emptyGlobalRdrEnv export_envs)
811 getModuleExports :: ModuleName -> IfG GlobalRdrEnv
813 = do { iface <- load_iface mod
814 ; avails <- exportsToAvails (mi_exports iface)
815 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod,
816 gre_deprec = mi_dep_fn iface name }
817 | avail <- avails, name <- availNames avail ] }
818 ; returnM (mkGlobalRdrEnv gres) }
820 vanillaProv :: ModuleName -> Provenance
821 -- We're building a GlobalRdrEnv as if the user imported
822 -- all the specified modules into the global interactive module
823 vanillaProv mod = Imported [ImportSpec mod mod False interactiveSrcLoc] False
829 -> InteractiveContext
830 -> ModuleName -- Module to inspect
831 -> Bool -- Grab just the exports, or the whole toplev
834 getModuleContents hsc_env ictxt mod exports_only
835 = initIfaceIO hsc_env (get_mod_contents exports_only)
837 get_mod_contents exports_only
838 | not exports_only -- We want the whole top-level type env
839 -- so it had better be a home module
841 ; case lookupModuleEnvByName hpt mod of
842 Just mod_info -> return (map (toIfaceDecl ictxt) $
845 md_types (hm_details mod_info))
846 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
847 -- This is a system error; the module should be in the HPT
850 | otherwise -- Want the exports only
851 = do { iface <- load_iface mod
852 ; avails <- exportsToAvails (mi_exports iface)
853 ; mappM get_decl avails
857 = do { thing <- tcIfaceGlobal (availName avail)
858 ; return (filter_decl (availOccs avail) (toIfaceDecl ictxt thing)) }
860 ---------------------
861 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
862 = decl { ifSigs = filter (keep_sig occs) sigs }
863 filter_decl occs decl@(IfaceData {ifCons = DataCons cons})
864 = decl { ifCons = DataCons (filter (keep_con occs) cons) }
865 filter_decl occs decl
868 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
869 keep_con occs (IfaceConDecl occ _ _ _ _ _) = occ `elem` occs
871 availOccs avail = map nameOccName (availNames avail)
873 wantToSee (AnId id) = not (isImplicitId id)
874 wantToSee (ADataCon _) = False -- They'll come via their TyCon
877 ---------------------
878 load_iface mod = loadSysInterface (text "context for compiling statements") mod
880 ---------------------
881 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
886 %************************************************************************
890 %************************************************************************
894 = do { ghci_mode <- getGhciMode ;
895 tcg_env <- getGblEnv ;
897 mb_main_mod <- readMutVar v_MainModIs ;
898 mb_main_fn <- readMutVar v_MainFunIs ;
899 let { main_mod = case mb_main_mod of {
900 Just mod -> mkModuleName mod ;
901 Nothing -> mAIN_Name } ;
902 main_fn = case mb_main_fn of {
903 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
904 Nothing -> main_RDR_Unqual } } ;
906 check_main ghci_mode tcg_env main_mod main_fn
910 check_main ghci_mode tcg_env main_mod main_fn
911 -- If we are in module Main, check that 'main' is defined.
912 -- It may be imported from another module!
914 -- ToDo: We have to return the main_name separately, because it's a
915 -- bona fide 'use', and should be recorded as such, but the others
918 -- Blimey: a whole page of code to do this...
919 | mod_name /= main_mod
923 = addErrCtxt mainCtxt $
924 do { mb_main <- lookupSrcOcc_maybe main_fn
925 -- Check that 'main' is in scope
926 -- It might be imported from another module!
928 Nothing -> do { complain_no_main
931 { let { rhs = HsApp (HsVar runIOName) (HsVar main_name) }
932 -- :Main.main :: IO () = runIO main
934 ; (main_expr, ty) <- addSrcLoc (getSrcLoc main_name) $
937 ; let { root_main_id = setIdLocalExported (mkLocalId rootMainName ty) ;
938 main_bind = VarMonoBind root_main_id main_expr }
940 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
941 `andMonoBinds` main_bind,
942 tcg_dus = tcg_dus tcg_env
943 `plusDU` usesOnly (unitFV main_name)
947 mod_name = moduleName (tcg_mod tcg_env)
949 complain_no_main | ghci_mode == Interactive = return ()
950 | otherwise = failWithTc noMainMsg
951 -- In interactive mode, don't worry about the absence of 'main'
952 -- In other modes, fail altogether, so that we don't go on
953 -- and complain a second time when processing the export list.
955 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
956 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
957 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
961 %************************************************************************
965 %************************************************************************
968 rnDump :: SDoc -> TcRn ()
969 -- Dump, with a banner, if -ddump-rn
970 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
972 tcDump :: TcGblEnv -> TcRn ()
974 = do { dflags <- getDOpts ;
976 -- Dump short output if -ddump-types or -ddump-tc
977 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
978 (dumpTcRn short_dump) ;
980 -- Dump bindings if -ddump-tc
981 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
984 short_dump = pprTcGblEnv env
985 full_dump = ppr (tcg_binds env)
986 -- NB: foreign x-d's have undefined's in their types;
987 -- hence can't show the tc_fords
990 = do { dflags <- getDOpts ;
991 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
992 (dumpTcRn (pprModGuts mod_guts)) ;
994 -- Dump bindings if -ddump-tc
995 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
997 full_dump = pprCoreBindings (mg_binds mod_guts)
999 -- It's unpleasant having both pprModGuts and pprModDetails here
1000 pprTcGblEnv :: TcGblEnv -> SDoc
1001 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1002 tcg_insts = dfun_ids,
1004 tcg_imports = imports })
1005 = vcat [ ppr_types dfun_ids type_env
1006 , ppr_insts dfun_ids
1007 , vcat (map ppr rules)
1008 , ppr_gen_tycons (typeEnvTyCons type_env)
1009 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1010 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1012 pprModGuts :: ModGuts -> SDoc
1013 pprModGuts (ModGuts { mg_types = type_env,
1015 = vcat [ ppr_types [] type_env,
1019 ppr_types :: [Var] -> TypeEnv -> SDoc
1020 ppr_types dfun_ids type_env
1021 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1023 ids = [id | id <- typeEnvIds type_env, want_sig id]
1024 want_sig id | opt_PprStyle_Debug = True
1025 | otherwise = isLocalId id &&
1026 isExternalName (idName id) &&
1027 not (id `elem` dfun_ids)
1028 -- isLocalId ignores data constructors, records selectors etc.
1029 -- The isExternalName ignores local dictionary and method bindings
1030 -- that the type checker has invented. Top-level user-defined things
1031 -- have External names.
1033 ppr_insts :: [Var] -> SDoc
1034 ppr_insts [] = empty
1035 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1037 ppr_sigs :: [Var] -> SDoc
1039 -- Print type signatures; sort by OccName
1040 = vcat (map ppr_sig (sortLt lt_sig ids))
1042 lt_sig id1 id2 = getOccName id1 < getOccName id2
1043 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1045 ppr_rules :: [IdCoreRule] -> SDoc
1046 ppr_rules [] = empty
1047 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1048 nest 4 (pprIdRules rs),
1051 ppr_gen_tycons [] = empty
1052 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1053 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]