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 )
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 ForeignStubs(NoStubs), TypeEnv, typeEnvTyCons,
66 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
70 import HsSyn ( HsStmtContext(..),
72 collectStmtsBinders, mkSimpleMatch, placeHolderType )
73 import RdrName ( GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
74 Provenance(..), ImportSpec(..),
75 lookupLocalRdrEnv, extendLocalRdrEnv )
76 import RnSource ( addTcgDUs )
77 import TcHsSyn ( mkHsLet, zonkTopLExpr, zonkTopBndrs )
78 import TcExpr ( tcCheckRho )
79 import TcMType ( zonkTcType )
80 import TcMatches ( tcStmtsAndThen, TcStmtCtxt(..) )
81 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
82 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType )
83 import TcEnv ( tcLookupTyCon, tcLookupId, tcLookupGlobal )
84 import Inst ( tcStdSyntaxName )
85 import RnExpr ( rnStmts, rnLExpr )
86 import RnNames ( exportsToAvails )
87 import LoadIface ( loadSrcInterface )
88 import IfaceSyn ( IfaceDecl(..), IfaceClassOp(..), IfaceConDecl(..),
89 IfaceExtName(..), IfaceConDecls(..),
91 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
92 import Id ( Id, isImplicitId )
93 import MkId ( unsafeCoerceId )
94 import TysWiredIn ( mkListTy, unitTy )
95 import IdInfo ( GlobalIdDetails(..) )
96 import SrcLoc ( interactiveSrcLoc, unLoc )
97 import Var ( globaliseId )
98 import Name ( nameOccName, nameModuleName )
99 import NameEnv ( delListFromNameEnv )
100 import PrelNames ( iNTERACTIVE, ioTyConName, printName, monadNames, itName, returnIOName )
101 import Module ( ModuleName, lookupModuleEnvByName )
102 import HscTypes ( InteractiveContext(..),
103 HomeModInfo(..), typeEnvElts,
104 TyThing(..), availName, availNames, icPrintUnqual,
105 ModIface(..), ModDetails(..) )
106 import BasicTypes ( RecFlag(..), Fixity )
107 import Bag ( unitBag )
108 import Panic ( ghcError, GhcException(..) )
111 import FastString ( mkFastString )
112 import Util ( sortLt )
113 import Bag ( unionBags, snocBag )
115 import Maybe ( isJust )
120 %************************************************************************
122 Typecheck and rename a module
124 %************************************************************************
129 -> Located (HsModule RdrName)
130 -> IO (Messages, Maybe TcGblEnv)
132 tcRnModule hsc_env (L loc (HsModule maybe_mod exports
133 import_decls local_decls mod_deprec))
134 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
136 let { this_mod = case maybe_mod of
137 Nothing -> mkHomeModule mAIN_Name
138 -- 'module M where' is omitted
139 Just (L _ mod) -> mod } ;
142 initTc hsc_env this_mod $
144 do { -- Deal with imports; sets tcg_rdr_env, tcg_imports
145 (rdr_env, imports) <- rnImports import_decls ;
146 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
147 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
149 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
150 -- Fail if there are any errors so far
151 -- The error printing (if needed) takes advantage
152 -- of the tcg_env we have now set
155 -- Load any orphan-module interfaces, so that
156 -- their rules and instance decls will be found
157 loadOrphanModules (imp_orphs imports) ;
159 traceRn (text "rn1a") ;
160 -- Rename and type check the declarations
161 tcg_env <- tcRnSrcDecls local_decls ;
162 setGblEnv tcg_env $ do {
164 traceRn (text "rn3") ;
166 -- Report the use of any deprecated things
167 -- We do this before processsing the export list so
168 -- that we don't bleat about re-exporting a deprecated
169 -- thing (especially via 'module Foo' export item)
170 -- Only uses in the body of the module are complained about
171 reportDeprecations tcg_env ;
173 -- Process the export list
174 exports <- exportsFromAvail (isJust maybe_mod) exports ;
176 {- Jan 04: I don't think this is necessary any more; usage info is derived from tcg_dus
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 ;
189 -- Check whether the entire module is deprecated
190 -- This happens only once per module
191 let { mod_deprecs = checkModDeprec mod_deprec } ;
193 -- Add exports and deprecations to envt
194 let { final_env = tcg_env { tcg_exports = exports,
195 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
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 = initTcPrintErrors 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 = initTcPrintErrors 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 = initTcPrintErrors 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 -} emptyNameSet {- Show data cons -}
475 unqual = icPrintUnqual ictxt
476 ext_nm n | unqual n = LocalTop (nameOccName n) -- What a hack
477 | otherwise = ExtPkg (nameModuleName n) (nameOccName n)
482 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
483 setInteractiveContext icxt thing_inside
484 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
485 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
486 tcg_type_env = ic_type_env icxt}) $
487 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
492 %************************************************************************
494 Type-checking external-core modules
496 %************************************************************************
499 tcRnExtCore :: HscEnv
501 -> IO (Messages, Maybe ModGuts)
502 -- Nothing => some error occurred
504 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
505 -- The decls are IfaceDecls; all names are original names
506 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
508 initTc hsc_env this_mod $ do {
510 let { ldecls = map noLoc decls } ;
512 -- Deal with the type declarations; first bring their stuff
513 -- into scope, then rname them, then type check them
514 (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup ldecls) ;
516 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
517 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
520 rn_decls <- rnTyClDecls ldecls ;
523 -- Dump trace of renaming part
524 rnDump (ppr rn_decls) ;
526 -- Typecheck them all together so that
527 -- any mutually recursive types are done right
528 tcg_env <- checkNoErrs (tcTyAndClassDecls rn_decls) ;
529 -- Make the new type env available to stuff slurped from interface files
531 setGblEnv tcg_env $ do {
533 -- Now the core bindings
534 core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;
538 bndrs = bindersOfBinds core_binds ;
539 my_exports = mkNameSet (map idName bndrs) ;
540 -- ToDo: export the data types also?
542 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
544 mod_guts = ModGuts { mg_module = this_mod,
545 mg_usages = [], -- ToDo: compute usage
546 mg_dir_imps = [], -- ??
547 mg_deps = noDependencies, -- ??
548 mg_exports = my_exports,
549 mg_types = final_type_env,
550 mg_insts = tcg_insts tcg_env,
552 mg_binds = core_binds,
555 mg_rdr_env = emptyGlobalRdrEnv,
556 mg_fix_env = emptyFixityEnv,
557 mg_deprecs = NoDeprecs,
561 tcCoreDump mod_guts ;
566 mkFakeGroup decls -- Rather clumsy; lots of unused fields
567 = HsGroup { hs_tyclds = decls, -- This is the one we want
568 hs_valds = [], hs_fords = [],
569 hs_instds = [], hs_fixds = [], hs_depds = [],
570 hs_ruleds = [], hs_defds = [] }
574 %************************************************************************
576 Type-checking the top level of a module
578 %************************************************************************
581 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
582 -- Returns the variables free in the decls
583 -- Reason: solely to report unused imports and bindings
585 = do { -- Do all the declarations
586 (tc_envs, lie) <- getLIE (tc_rn_src_decls decls) ;
588 -- tcSimplifyTop deals with constant or ambiguous InstIds.
589 -- How could there be ambiguous ones? They can only arise if a
590 -- top-level decl falls under the monomorphism
591 -- restriction, and no subsequent decl instantiates its
592 -- type. (Usually, ambiguous type variables are resolved
593 -- during the generalisation step.)
594 traceTc (text "Tc8") ;
595 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
596 -- Setting the global env exposes the instances to tcSimplifyTop
597 -- Setting the local env exposes the local Ids to tcSimplifyTop,
598 -- so that we get better error messages (monomorphism restriction)
600 -- Backsubstitution. This must be done last.
601 -- Even tcSimplifyTop may do some unification.
602 traceTc (text "Tc9") ;
603 let { (tcg_env, _) = tc_envs ;
604 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
605 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
607 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
610 let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
612 -- Make the new type env available to stuff slurped from interface files
613 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
615 return (tcg_env { tcg_type_env = final_type_env,
616 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' })
619 tc_rn_src_decls :: [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
620 -- Loops around dealing with each top level inter-splice group
621 -- in turn, until it's dealt with the entire module
623 = do { let { (first_group, group_tail) = findSplice ds } ;
624 -- If ds is [] we get ([], Nothing)
626 -- Type check the decls up to, but not including, the first splice
627 tc_envs@(tcg_env,tcl_env) <- tcRnGroup first_group ;
629 -- Bale out if errors; for example, error recovery when checking
630 -- the RHS of 'main' can mean that 'main' is not in the envt for
631 -- the subsequent checkMain test
636 -- If there is no splice, we're nearly done
638 Nothing -> do { -- Last thing: check for `main'
639 tcg_env <- checkMain ;
640 return (tcg_env, tcl_env)
643 -- If there's a splice, we must carry on
644 Just (SpliceDecl splice_expr, rest_ds) -> do {
646 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
649 -- Rename the splice expression, and get its supporting decls
650 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
651 failIfErrsM ; -- Don't typecheck if renaming failed
653 -- Execute the splice
654 spliced_decls <- tcSpliceDecls rn_splice_expr ;
656 -- Glue them on the front of the remaining decls and loop
657 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
658 tc_rn_src_decls (spliced_decls ++ rest_ds)
664 %************************************************************************
666 Type-checking the top level of a module
668 %************************************************************************
670 tcRnGroup takes a bunch of top-level source-code declarations, and
672 * gets supporting declarations from interface files
675 * and augments the TcGblEnv with the results
677 In Template Haskell it may be called repeatedly for each group of
678 declarations. It expects there to be an incoming TcGblEnv in the
679 monad; it augments it and returns the new TcGblEnv.
682 tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
683 -- Returns the variables free in the decls, for unused-binding reporting
685 = do { -- Rename the declarations
686 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
687 setGblEnv tcg_env $ do {
689 -- Typecheck the declarations
690 tcTopSrcDecls rn_decls
693 ------------------------------------------------
694 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
696 = do { -- Bring top level binders into scope
697 (rdr_env, imports) <- importsFromLocalDecls group ;
698 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
699 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
702 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
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 ++ 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 `unionBags`
778 inst_binds `unionBags`
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 `unionBags` 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 = do { mb_envs <- initTcPrintErrors hsc_env iNTERACTIVE $
807 mappM getModuleExports exports
809 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
810 Nothing -> return emptyGlobalRdrEnv
811 -- Some error; initTc will have printed it
814 getModuleExports :: ModuleName -> TcM GlobalRdrEnv
816 = do { iface <- load_iface mod
817 ; avails <- exportsToAvails (mi_exports iface)
818 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
819 | avail <- avails, name <- availNames avail ] }
820 ; returnM (mkGlobalRdrEnv gres) }
822 vanillaProv :: ModuleName -> Provenance
823 -- We're building a GlobalRdrEnv as if the user imported
824 -- all the specified modules into the global interactive module
825 vanillaProv mod = Imported [ImportSpec mod mod False
826 (srcLocSpan interactiveSrcLoc)] False
832 -> InteractiveContext
833 -> ModuleName -- Module to inspect
834 -> Bool -- Grab just the exports, or the whole toplev
835 -> IO (Maybe [IfaceDecl])
837 getModuleContents hsc_env ictxt mod exports_only
838 = initTcPrintErrors hsc_env iNTERACTIVE (get_mod_contents exports_only)
840 get_mod_contents exports_only
841 | not exports_only -- We want the whole top-level type env
842 -- so it had better be a home module
844 ; case lookupModuleEnvByName hpt mod of
845 Just mod_info -> return (map (toIfaceDecl ictxt) $
848 md_types (hm_details mod_info))
849 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
850 -- This is a system error; the module should be in the HPT
853 | otherwise -- Want the exports only
854 = do { iface <- load_iface mod
855 ; avails <- exportsToAvails (mi_exports iface)
856 ; mappM get_decl avails
860 = do { thing <- tcLookupGlobal (availName avail)
861 ; return (filter_decl (availOccs avail) (toIfaceDecl ictxt thing)) }
863 ---------------------
864 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
865 = decl { ifSigs = filter (keep_sig occs) sigs }
866 filter_decl occs decl@(IfaceData {ifCons = IfDataTyCon cons})
867 = decl { ifCons = IfDataTyCon (filter (keep_con occs) cons) }
868 filter_decl occs decl@(IfaceData {ifCons = IfNewTyCon con})
869 | keep_con occs con = decl
870 | otherwise = decl {ifCons = IfAbstractTyCon} -- Hmm?
871 filter_decl occs decl
874 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
875 keep_con occs (IfaceConDecl occ _ _ _ _ _) = occ `elem` occs
877 availOccs avail = map nameOccName (availNames avail)
879 wantToSee (AnId id) = not (isImplicitId id)
880 wantToSee (ADataCon _) = False -- They'll come via their TyCon
883 ---------------------
884 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
886 doc = ptext SLIT("context for compiling statements")
888 ---------------------
889 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
894 %************************************************************************
898 %************************************************************************
902 = do { ghci_mode <- getGhciMode ;
903 tcg_env <- getGblEnv ;
905 mb_main_mod <- readMutVar v_MainModIs ;
906 mb_main_fn <- readMutVar v_MainFunIs ;
907 let { main_mod = case mb_main_mod of {
908 Just mod -> mkModuleName mod ;
909 Nothing -> mAIN_Name } ;
910 main_fn = case mb_main_fn of {
911 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
912 Nothing -> main_RDR_Unqual } } ;
914 check_main ghci_mode tcg_env main_mod main_fn
918 check_main ghci_mode tcg_env main_mod main_fn
919 -- If we are in module Main, check that 'main' is defined.
920 -- It may be imported from another module!
922 -- ToDo: We have to return the main_name separately, because it's a
923 -- bona fide 'use', and should be recorded as such, but the others
926 -- Blimey: a whole page of code to do this...
927 | mod_name /= main_mod
931 = addErrCtxt mainCtxt $
932 do { mb_main <- lookupSrcOcc_maybe main_fn
933 -- Check that 'main' is in scope
934 -- It might be imported from another module!
936 Nothing -> do { complain_no_main
939 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
940 -- :Main.main :: IO () = runIO main
942 ; (main_expr, ty) <- addSrcSpan (srcLocSpan (getSrcLoc main_name)) $
945 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
946 main_bind = noLoc (VarBind root_main_id main_expr) }
948 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
950 tcg_dus = tcg_dus tcg_env
951 `plusDU` usesOnly (unitFV main_name)
955 mod_name = moduleName (tcg_mod tcg_env)
957 complain_no_main | ghci_mode == Interactive = return ()
958 | otherwise = failWithTc noMainMsg
959 -- In interactive mode, don't worry about the absence of 'main'
960 -- In other modes, fail altogether, so that we don't go on
961 -- and complain a second time when processing the export list.
963 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
964 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
965 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
969 %************************************************************************
973 %************************************************************************
976 rnDump :: SDoc -> TcRn ()
977 -- Dump, with a banner, if -ddump-rn
978 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
980 tcDump :: TcGblEnv -> TcRn ()
982 = do { dflags <- getDOpts ;
984 -- Dump short output if -ddump-types or -ddump-tc
985 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
986 (dumpTcRn short_dump) ;
988 -- Dump bindings if -ddump-tc
989 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
992 short_dump = pprTcGblEnv env
993 full_dump = ppr (tcg_binds env)
994 -- NB: foreign x-d's have undefined's in their types;
995 -- hence can't show the tc_fords
998 = do { dflags <- getDOpts ;
999 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1000 (dumpTcRn (pprModGuts mod_guts)) ;
1002 -- Dump bindings if -ddump-tc
1003 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1005 full_dump = pprCoreBindings (mg_binds mod_guts)
1007 -- It's unpleasant having both pprModGuts and pprModDetails here
1008 pprTcGblEnv :: TcGblEnv -> SDoc
1009 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1010 tcg_insts = dfun_ids,
1012 tcg_imports = imports })
1013 = vcat [ ppr_types dfun_ids type_env
1014 , ppr_insts dfun_ids
1015 , vcat (map ppr rules)
1016 , ppr_gen_tycons (typeEnvTyCons type_env)
1017 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1018 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1020 pprModGuts :: ModGuts -> SDoc
1021 pprModGuts (ModGuts { mg_types = type_env,
1023 = vcat [ ppr_types [] type_env,
1027 ppr_types :: [Var] -> TypeEnv -> SDoc
1028 ppr_types dfun_ids type_env
1029 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1031 ids = [id | id <- typeEnvIds type_env, want_sig id]
1032 want_sig id | opt_PprStyle_Debug = True
1033 | otherwise = isLocalId id &&
1034 isExternalName (idName id) &&
1035 not (id `elem` dfun_ids)
1036 -- isLocalId ignores data constructors, records selectors etc.
1037 -- The isExternalName ignores local dictionary and method bindings
1038 -- that the type checker has invented. Top-level user-defined things
1039 -- have External names.
1041 ppr_insts :: [Var] -> SDoc
1042 ppr_insts [] = empty
1043 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1045 ppr_sigs :: [Var] -> SDoc
1047 -- Print type signatures; sort by OccName
1048 = vcat (map ppr_sig (sortLt lt_sig ids))
1050 lt_sig id1 id2 = getOccName id1 < getOccName id2
1051 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1053 ppr_rules :: [IdCoreRule] -> SDoc
1054 ppr_rules [] = empty
1055 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1056 nest 4 (pprIdRules rs),
1059 ppr_gen_tycons [] = empty
1060 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1061 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]