2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
9 mkExportEnv, getModuleContents, tcRnStmt, tcRnThing, tcRnExpr,
16 #include "HsVersions.h"
19 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
22 import CmdLineOpts ( DynFlag(..), opt_PprStyle_Debug, dopt )
23 import DriverState ( v_MainModIs, v_MainFunIs )
25 import RdrHsSyn ( findSplice )
27 import PrelNames ( runIOName, rootMainName, mAIN_Name,
29 import RdrName ( RdrName, mkRdrUnqual, emptyGlobalRdrEnv,
31 import TcHsSyn ( zonkTopDecls )
32 import TcExpr ( tcInferRho )
34 import TcType ( tidyTopType )
35 import Inst ( showLIE )
36 import TcBinds ( tcTopBinds )
37 import TcDefaults ( tcDefaults )
38 import TcEnv ( tcExtendGlobalValEnv, tcLookupGlobal )
39 import TcRules ( tcRules )
40 import TcForeign ( tcForeignImports, tcForeignExports )
41 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
42 import TcIface ( tcExtCoreBindings )
43 import TcSimplify ( tcSimplifyTop )
44 import TcTyClsDecls ( tcTyAndClassDecls )
45 import LoadIface ( loadOrphanModules )
46 import RnNames ( importsFromLocalDecls, rnImports, exportsFromAvail,
47 reportUnusedNames, reportDeprecations )
48 import RnEnv ( lookupSrcOcc_maybe )
49 import RnSource ( rnSrcDecls, rnTyClDecls, checkModDeprec )
50 import PprCore ( pprIdRules, pprCoreBindings )
51 import CoreSyn ( IdCoreRule, bindersOfBinds )
52 import ErrUtils ( mkDumpDoc, showPass )
53 import Id ( mkExportedLocalId, isLocalId, idName, idType )
55 import Module ( mkHomeModule, mkModuleName, moduleName, moduleEnvElts )
56 import OccName ( mkVarOcc )
57 import Name ( Name, isExternalName, getSrcLoc, getOccName )
59 import TyCon ( tyConHasGenerics )
60 import SrcLoc ( srcLocSpan, Located(..), noLoc )
62 import HscTypes ( ModGuts(..), HscEnv(..),
63 GhciMode(..), noDependencies,
64 Deprecs( NoDeprecs ), plusDeprecs,
65 GenAvailInfo(Avail), availsToNameSet, availName,
66 ForeignStubs(NoStubs), TypeEnv, typeEnvTyCons,
67 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
71 import HsSyn ( HsStmtContext(..),
73 collectStmtsBinders, mkSimpleMatch, placeHolderType )
74 import RdrName ( GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
75 Provenance(..), ImportSpec(..),
76 lookupLocalRdrEnv, extendLocalRdrEnv )
77 import RnSource ( addTcgDUs )
78 import TcHsSyn ( mkHsLet, zonkTopLExpr, zonkTopBndrs )
79 import TcExpr ( tcCheckRho )
80 import TcMType ( zonkTcType )
81 import TcMatches ( tcStmtsAndThen, TcStmtCtxt(..) )
82 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
83 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType )
84 import TcEnv ( tcLookupTyCon, tcLookupId )
85 import TyCon ( DataConDetails(..) )
86 import Inst ( tcStdSyntaxName )
87 import RnExpr ( rnStmts, rnLExpr )
88 import RnNames ( exportsToAvails )
89 import LoadIface ( loadSrcInterface )
90 import IfaceSyn ( IfaceDecl(..), IfaceClassOp(..), IfaceConDecl(..), IfaceExtName(..),
92 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
93 import Id ( Id, isImplicitId )
94 import MkId ( unsafeCoerceId )
95 import TysWiredIn ( mkListTy, unitTy )
96 import IdInfo ( GlobalIdDetails(..) )
97 import SrcLoc ( interactiveSrcLoc, unLoc )
98 import Var ( setGlobalIdDetails )
99 import Name ( nameOccName, nameModuleName )
100 import NameEnv ( delListFromNameEnv )
101 import PrelNames ( iNTERACTIVE, ioTyConName, printName, monadNames, itName, returnIOName )
102 import Module ( ModuleName, lookupModuleEnvByName )
103 import HscTypes ( InteractiveContext(..),
104 HomeModInfo(..), typeEnvElts,
105 TyThing(..), availNames, icPrintUnqual,
106 ModIface(..), ModDetails(..) )
107 import BasicTypes ( RecFlag(..), Fixity )
108 import Bag ( unitBag )
109 import Panic ( ghcError, GhcException(..) )
112 import FastString ( mkFastString )
113 import Util ( sortLt )
114 import Bag ( unionBags, snocBag )
116 import Maybe ( isJust )
121 %************************************************************************
123 Typecheck and rename a module
125 %************************************************************************
130 -> Located (HsModule RdrName)
131 -> IO (Maybe TcGblEnv)
133 tcRnModule hsc_env (L loc (HsModule maybe_mod exports
134 import_decls local_decls mod_deprec))
135 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
137 let { this_mod = case maybe_mod of
138 Nothing -> mkHomeModule mAIN_Name
139 -- 'module M where' is omitted
140 Just (L _ mod) -> mod } ;
143 initTc hsc_env this_mod $
145 do { -- Deal with imports; sets tcg_rdr_env, tcg_imports
146 (rdr_env, imports) <- rnImports import_decls ;
147 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
148 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
150 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
151 -- Fail if there are any errors so far
152 -- The error printing (if needed) takes advantage
153 -- of the tcg_env we have now set
156 -- Load any orphan-module interfaces, so that
157 -- their rules and instance decls will be found
158 loadOrphanModules (imp_orphs imports) ;
160 traceRn (text "rn1a") ;
161 -- Rename and type check the declarations
162 tcg_env <- tcRnSrcDecls local_decls ;
163 setGblEnv tcg_env $ do {
165 traceRn (text "rn3") ;
167 -- Report the use of any deprecated things
168 -- We do this before processsing the export list so
169 -- that we don't bleat about re-exporting a deprecated
170 -- thing (especially via 'module Foo' export item)
171 -- Only uses in the body of the module are complained about
172 reportDeprecations tcg_env ;
174 -- Process the export list
175 export_avails <- exportsFromAvail (isJust maybe_mod) exports ;
177 -- Get any supporting decls for the exports that have not already
178 -- been sucked in for the declarations in the body of the module.
179 -- (This can happen if something is imported only to be re-exported.)
181 -- Importing these supporting declarations is required
182 -- *only* to gether usage information
183 -- (see comments with MkIface.mkImportInfo for why)
184 -- We don't need the results, but sucking them in may side-effect
185 -- the ExternalPackageState, apart from recording usage
186 mappM (tcLookupGlobal . availName) export_avails ;
188 -- Check whether the entire module is deprecated
189 -- This happens only once per module
190 let { mod_deprecs = checkModDeprec mod_deprec } ;
192 -- Add exports and deprecations to envt
193 let { export_fvs = availsToNameSet export_avails ;
194 final_env = tcg_env { tcg_exports = export_avails,
195 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly export_fvs,
196 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
198 -- A module deprecation over-rides the earlier ones
201 -- Report unused names
202 reportUnusedNames final_env ;
204 -- Dump output and return
211 %************************************************************************
213 The interactive interface
215 %************************************************************************
220 -> InteractiveContext
222 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
223 -- The returned [Name] is the same as the input except for
224 -- ExprStmt, in which case the returned [Name] is [itName]
226 -- The returned TypecheckedHsExpr is of type IO [ () ],
227 -- a list of the bound values, coerced to ().
229 tcRnStmt hsc_env ictxt rdr_stmt
230 = initTc hsc_env iNTERACTIVE $
231 setInteractiveContext ictxt $ do {
233 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
234 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
235 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
238 -- The real work is done here
239 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
241 traceTc (text "tcs 1") ;
242 let { -- Make all the bound ids "global" ids, now that
243 -- they're notionally top-level bindings. This is
244 -- important: otherwise when we come to compile an expression
245 -- using these ids later, the byte code generator will consider
246 -- the occurrences to be free rather than global.
247 global_ids = map globaliseId bound_ids ;
248 globaliseId id = setGlobalIdDetails id VanillaGlobal ;
250 -- Update the interactive context
251 rn_env = ic_rn_local_env ictxt ;
252 type_env = ic_type_env ictxt ;
254 bound_names = map idName global_ids ;
255 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
257 -- Remove any shadowed bindings from the type_env;
258 -- they are inaccessible but might, I suppose, cause
259 -- a space leak if we leave them there
260 shadowed = [ n | name <- bound_names,
261 let rdr_name = mkRdrUnqual (nameOccName name),
262 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
264 filtered_type_env = delListFromNameEnv type_env shadowed ;
265 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
267 new_ic = ictxt { ic_rn_local_env = new_rn_env,
268 ic_type_env = new_type_env }
271 dumpOptTcRn Opt_D_dump_tc
272 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
273 text "Typechecked expr" <+> ppr tc_expr]) ;
275 returnM (new_ic, bound_names, tc_expr)
280 Here is the grand plan, implemented in tcUserStmt
282 What you type The IO [HValue] that hscStmt returns
283 ------------- ------------------------------------
284 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
287 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
290 expr (of IO type) ==> expr >>= \ v -> return [coerce HVal v]
291 [NB: result not printed] bindings: [it]
293 expr (of non-IO type, ==> let v = expr in print v >> return [coerce HVal v]
294 result showable) bindings: [it]
296 expr (of non-IO type,
297 result not showable) ==> error
301 ---------------------------
302 tcUserStmt :: LStmt Name -> TcM ([Id], LHsExpr Id)
303 tcUserStmt (L _ (ExprStmt expr _))
304 = newUnique `thenM` \ uniq ->
306 fresh_it = itName uniq
307 the_bind = noLoc $ FunBind (noLoc fresh_it) False
308 [ mkSimpleMatch [] expr placeHolderType ]
310 tryTcLIE_ (do { -- Try this if the other fails
311 traceTc (text "tcs 1b") ;
313 nlLetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive],
314 nlExprStmt (nlHsApp (nlHsVar printName)
317 (do { -- Try this first
318 traceTc (text "tcs 1a") ;
319 tc_stmts [nlBindStmt (nlVarPat fresh_it) expr] })
321 tcUserStmt stmt = tc_stmts [stmt]
323 ---------------------------
325 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
327 ret_ty = mkListTy unitTy ;
328 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
330 names = map unLoc (collectStmtsBinders stmts) ;
332 stmt_ctxt = SC { sc_what = DoExpr,
334 sc_body = check_body,
337 check_rhs rhs rhs_ty = tcCheckRho rhs (mkTyConApp ioTyCon [rhs_ty]) ;
338 check_body body = tcCheckRho body io_ret_ty ;
340 -- mk_return builds the expression
341 -- returnIO @ [()] [coerce () x, .., coerce () z]
343 -- Despite the inconvenience of building the type applications etc,
344 -- this *has* to be done in type-annotated post-typecheck form
345 -- because we are going to return a list of *polymorphic* values
346 -- coerced to type (). If we built a *source* stmt
347 -- return [coerce x, ..., coerce z]
348 -- then the type checker would instantiate x..z, and we wouldn't
349 -- get their *polymorphic* values. (And we'd get ambiguity errs
350 -- if they were overloaded, since they aren't applied to anything.)
351 mk_return ret_id ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
352 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
353 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
356 io_ty = mkTyConApp ioTyCon []
359 -- OK, we're ready to typecheck the stmts
360 traceTc (text "tcs 2") ;
361 ((ids, tc_expr), lie) <- getLIE $ do {
362 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
364 -- Look up the names right in the middle,
365 -- where they will all be in scope
366 ids <- mappM tcLookupId names ;
367 ret_id <- tcLookupId returnIOName ; -- return @ IO
368 return (ids, [nlResultStmt (mk_return ret_id ids)]) } ;
370 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
371 return (ids, noLoc (HsDo DoExpr tc_stmts io_ids io_ret_ty))
374 -- Simplify the context right here, so that we fail
375 -- if there aren't enough instances. Notably, when we see
377 -- we use recoverTc_ to try it <- e
378 -- and then let it = e
379 -- It's the simplify step that rejects the first.
380 traceTc (text "tcs 3") ;
381 const_binds <- tcSimplifyInteractive lie ;
383 -- Build result expression and zonk it
384 let { expr = mkHsLet const_binds tc_expr } ;
385 zonked_expr <- zonkTopLExpr expr ;
386 zonked_ids <- zonkTopBndrs ids ;
388 return (zonked_ids, zonked_expr)
391 combine stmt (ids, stmts) = (ids, stmt:stmts)
395 tcRnExpr just finds the type of an expression
399 -> InteractiveContext
402 tcRnExpr hsc_env ictxt rdr_expr
403 = initTc hsc_env iNTERACTIVE $
404 setInteractiveContext ictxt $ do {
406 (rn_expr, fvs) <- rnLExpr rdr_expr ;
409 -- Now typecheck the expression;
410 -- it might have a rank-2 type (e.g. :t runST)
411 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
412 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
413 tcSimplifyInteractive lie_top ;
415 let { all_expr_ty = mkForAllTys qtvs $
416 mkFunTys (map idType dict_ids) $
418 zonkTcType all_expr_ty
421 smpl_doc = ptext SLIT("main expression")
427 -> InteractiveContext
429 -> IO (Maybe [(IfaceDecl, Fixity)])
430 -- Look up a RdrName and return all the TyThings it might be
431 -- A capitalised RdrName is given to us in the DataName namespace,
432 -- but we want to treat it as *both* a data constructor
433 -- *and* as a type or class constructor;
434 -- hence the call to dataTcOccs, and we return up to two results
435 tcRnThing hsc_env ictxt rdr_name
436 = initTc hsc_env iNTERACTIVE $
437 setInteractiveContext ictxt $ do {
439 -- If the identifier is a constructor (begins with an
440 -- upper-case letter), then we need to consider both
441 -- constructor and type class identifiers.
442 let { rdr_names = dataTcOccs rdr_name } ;
444 -- results :: [(Messages, Maybe Name)]
445 results <- mapM (tryTc . lookupOccRn) rdr_names ;
447 -- The successful lookups will be (Just name)
448 let { (warns_s, good_names) = unzip [ (msgs, name)
449 | (msgs, Just name) <- results] ;
450 errs_s = [msgs | (msgs, Nothing) <- results] } ;
452 -- Fail if nothing good happened, else add warnings
453 if null good_names then
454 -- No lookup succeeded, so
455 -- pick the first error message and report it
456 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
457 -- while the other is "X is not in scope",
458 -- we definitely want the former; but we might pick the latter
459 do { addMessages (head errs_s) ; failM }
460 else -- Add deprecation warnings
461 mapM_ addMessages warns_s ;
463 -- And lookup up the entities
464 mapM do_one good_names
467 do_one name = do { thing <- tcLookupGlobal name
468 ; fixity <- lookupFixityRn name
469 ; return (toIfaceDecl ictxt thing, fixity) }
471 toIfaceDecl :: InteractiveContext -> TyThing -> IfaceDecl
472 toIfaceDecl ictxt thing
473 = tyThingToIfaceDecl True {- Discard IdInfo -} ext_nm thing
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 (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 = map (Avail . 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 <- initTc 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 = initTc 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 = DataCons cons})
867 = decl { ifCons = DataCons (filter (keep_con occs) cons) }
868 filter_decl occs decl
871 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
872 keep_con occs (IfaceConDecl occ _ _ _ _ _) = occ `elem` occs
874 availOccs avail = map nameOccName (availNames avail)
876 wantToSee (AnId id) = not (isImplicitId id)
877 wantToSee (ADataCon _) = False -- They'll come via their TyCon
880 ---------------------
881 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
883 doc = ptext SLIT("context for compiling statements")
885 ---------------------
886 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
891 %************************************************************************
895 %************************************************************************
899 = do { ghci_mode <- getGhciMode ;
900 tcg_env <- getGblEnv ;
902 mb_main_mod <- readMutVar v_MainModIs ;
903 mb_main_fn <- readMutVar v_MainFunIs ;
904 let { main_mod = case mb_main_mod of {
905 Just mod -> mkModuleName mod ;
906 Nothing -> mAIN_Name } ;
907 main_fn = case mb_main_fn of {
908 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
909 Nothing -> main_RDR_Unqual } } ;
911 check_main ghci_mode tcg_env main_mod main_fn
915 check_main ghci_mode tcg_env main_mod main_fn
916 -- If we are in module Main, check that 'main' is defined.
917 -- It may be imported from another module!
919 -- ToDo: We have to return the main_name separately, because it's a
920 -- bona fide 'use', and should be recorded as such, but the others
923 -- Blimey: a whole page of code to do this...
924 | mod_name /= main_mod
928 = addErrCtxt mainCtxt $
929 do { mb_main <- lookupSrcOcc_maybe main_fn
930 -- Check that 'main' is in scope
931 -- It might be imported from another module!
933 Nothing -> do { complain_no_main
936 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
937 -- :Main.main :: IO () = runIO main
939 ; (main_expr, ty) <- addSrcSpan (srcLocSpan (getSrcLoc main_name)) $
942 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
943 main_bind = noLoc (VarBind root_main_id main_expr) }
945 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
947 tcg_dus = tcg_dus tcg_env
948 `plusDU` usesOnly (unitFV main_name)
952 mod_name = moduleName (tcg_mod tcg_env)
954 complain_no_main | ghci_mode == Interactive = return ()
955 | otherwise = failWithTc noMainMsg
956 -- In interactive mode, don't worry about the absence of 'main'
957 -- In other modes, fail altogether, so that we don't go on
958 -- and complain a second time when processing the export list.
960 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
961 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
962 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
966 %************************************************************************
970 %************************************************************************
973 rnDump :: SDoc -> TcRn ()
974 -- Dump, with a banner, if -ddump-rn
975 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
977 tcDump :: TcGblEnv -> TcRn ()
979 = do { dflags <- getDOpts ;
981 -- Dump short output if -ddump-types or -ddump-tc
982 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
983 (dumpTcRn short_dump) ;
985 -- Dump bindings if -ddump-tc
986 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
989 short_dump = pprTcGblEnv env
990 full_dump = ppr (tcg_binds env)
991 -- NB: foreign x-d's have undefined's in their types;
992 -- hence can't show the tc_fords
995 = do { dflags <- getDOpts ;
996 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
997 (dumpTcRn (pprModGuts mod_guts)) ;
999 -- Dump bindings if -ddump-tc
1000 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1002 full_dump = pprCoreBindings (mg_binds mod_guts)
1004 -- It's unpleasant having both pprModGuts and pprModDetails here
1005 pprTcGblEnv :: TcGblEnv -> SDoc
1006 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1007 tcg_insts = dfun_ids,
1009 tcg_imports = imports })
1010 = vcat [ ppr_types dfun_ids type_env
1011 , ppr_insts dfun_ids
1012 , vcat (map ppr rules)
1013 , ppr_gen_tycons (typeEnvTyCons type_env)
1014 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1015 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1017 pprModGuts :: ModGuts -> SDoc
1018 pprModGuts (ModGuts { mg_types = type_env,
1020 = vcat [ ppr_types [] type_env,
1024 ppr_types :: [Var] -> TypeEnv -> SDoc
1025 ppr_types dfun_ids type_env
1026 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1028 ids = [id | id <- typeEnvIds type_env, want_sig id]
1029 want_sig id | opt_PprStyle_Debug = True
1030 | otherwise = isLocalId id &&
1031 isExternalName (idName id) &&
1032 not (id `elem` dfun_ids)
1033 -- isLocalId ignores data constructors, records selectors etc.
1034 -- The isExternalName ignores local dictionary and method bindings
1035 -- that the type checker has invented. Top-level user-defined things
1036 -- have External names.
1038 ppr_insts :: [Var] -> SDoc
1039 ppr_insts [] = empty
1040 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1042 ppr_sigs :: [Var] -> SDoc
1044 -- Print type signatures; sort by OccName
1045 = vcat (map ppr_sig (sortLt lt_sig ids))
1047 lt_sig id1 id2 = getOccName id1 < getOccName id2
1048 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1050 ppr_rules :: [IdCoreRule] -> SDoc
1051 ppr_rules [] = empty
1052 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1053 nest 4 (pprIdRules rs),
1056 ppr_gen_tycons [] = empty
1057 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1058 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]