2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
9 mkExportEnv, getModuleContents, tcRnStmt,
10 tcRnThing, tcRnExpr, tcRnType,
17 #include "HsVersions.h"
20 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
23 import CmdLineOpts ( DynFlag(..), opt_PprStyle_Debug, dopt )
24 import DriverState ( v_MainModIs, v_MainFunIs )
25 import HsSyn ( HsModule(..), HsExtCore(..), HsGroup(..), LHsDecl, SpliceDecl(..), HsBind(..),
26 nlHsApp, nlHsVar, pprLHsBinds )
27 import RdrHsSyn ( findSplice )
29 import PrelNames ( runIOName, rootMainName, mAIN_Name,
31 import RdrName ( RdrName, mkRdrUnqual, emptyGlobalRdrEnv,
33 import TcHsSyn ( zonkTopDecls )
34 import TcExpr ( tcInferRho )
36 import TcType ( tidyTopType, isUnLiftedType )
37 import Inst ( showLIE )
38 import TcBinds ( tcTopBinds )
39 import TcDefaults ( tcDefaults )
40 import TcEnv ( tcExtendGlobalValEnv )
41 import TcRules ( tcRules )
42 import TcForeign ( tcForeignImports, tcForeignExports )
43 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
44 import TcIface ( tcExtCoreBindings )
45 import TcSimplify ( tcSimplifyTop )
46 import TcTyClsDecls ( tcTyAndClassDecls )
47 import LoadIface ( loadOrphanModules )
48 import RnNames ( importsFromLocalDecls, rnImports, exportsFromAvail,
49 reportUnusedNames, reportDeprecations )
50 import RnEnv ( lookupSrcOcc_maybe )
51 import RnSource ( rnSrcDecls, rnTyClDecls, checkModDeprec )
52 import PprCore ( pprIdRules, pprCoreBindings )
53 import CoreSyn ( IdCoreRule, bindersOfBinds )
54 import ErrUtils ( Messages, mkDumpDoc, showPass )
55 import Id ( mkExportedLocalId, isLocalId, idName, idType )
57 import Module ( mkHomeModule, mkModuleName, moduleName, moduleEnvElts )
58 import OccName ( mkVarOcc )
59 import Name ( Name, isExternalName, getSrcLoc, getOccName )
61 import TyCon ( tyConHasGenerics )
62 import SrcLoc ( srcLocSpan, Located(..), noLoc )
64 import HscTypes ( ModGuts(..), HscEnv(..),
65 GhciMode(..), noDependencies,
66 Deprecs( NoDeprecs ), plusDeprecs,
67 ForeignStubs(NoStubs), TypeEnv,
68 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
72 import HsSyn ( HsStmtContext(..), Stmt(..), HsExpr(..), HsBindGroup(..),
73 LStmt, LHsExpr, LHsType,
74 collectStmtsBinders, mkSimpleMatch, placeHolderType,
75 nlLetStmt, nlExprStmt, nlBindStmt, nlResultStmt, nlVarPat )
76 import RdrName ( GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
77 Provenance(..), ImportSpec(..),
78 lookupLocalRdrEnv, extendLocalRdrEnv )
79 import RnSource ( addTcgDUs )
80 import TcHsSyn ( mkHsLet, zonkTopLExpr, zonkTopBndrs )
81 import TcHsType ( kcHsType )
82 import TcExpr ( tcCheckRho )
83 import TcMType ( zonkTcType )
84 import TcMatches ( tcStmtsAndThen, TcStmtCtxt(..) )
85 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
86 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType )
87 import TcEnv ( tcLookupTyCon, tcLookupId, tcLookupGlobal )
88 import RnTypes ( rnLHsType )
89 import Inst ( tcStdSyntaxName )
90 import RnExpr ( rnStmts, rnLExpr )
91 import RnNames ( exportsToAvails )
92 import LoadIface ( loadSrcInterface )
93 import IfaceSyn ( IfaceDecl(..), IfaceClassOp(..), IfaceConDecl(..),
94 IfaceExtName(..), IfaceConDecls(..),
96 import RnEnv ( lookupOccRn, dataTcOccs, lookupFixityRn )
97 import Id ( Id, isImplicitId )
98 import MkId ( unsafeCoerceId )
99 import TysWiredIn ( mkListTy, unitTy )
100 import IdInfo ( GlobalIdDetails(..) )
101 import SrcLoc ( interactiveSrcLoc, unLoc )
103 import Var ( globaliseId )
104 import Name ( nameOccName, nameModuleName )
105 import NameEnv ( delListFromNameEnv )
106 import PrelNames ( iNTERACTIVE, ioTyConName, printName, monadNames, itName, returnIOName )
107 import Module ( ModuleName, lookupModuleEnvByName )
108 import HscTypes ( InteractiveContext(..),
109 HomeModInfo(..), typeEnvElts,
110 TyThing(..), availName, availNames, icPrintUnqual,
111 ModIface(..), ModDetails(..) )
112 import BasicTypes ( RecFlag(..), Fixity )
113 import Bag ( unitBag )
114 import Panic ( ghcError, GhcException(..) )
117 import FastString ( mkFastString )
118 import Util ( sortLt )
119 import Bag ( unionBags, snocBag )
121 import Maybe ( isJust )
126 %************************************************************************
128 Typecheck and rename a module
130 %************************************************************************
135 -> Located (HsModule RdrName)
136 -> IO (Messages, Maybe TcGblEnv)
138 tcRnModule hsc_env (L loc (HsModule maybe_mod exports
139 import_decls local_decls mod_deprec))
140 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
142 let { this_mod = case maybe_mod of
143 Nothing -> mkHomeModule mAIN_Name
144 -- 'module M where' is omitted
145 Just (L _ mod) -> mod } ;
148 initTc hsc_env this_mod $
150 do { -- Deal with imports; sets tcg_rdr_env, tcg_imports
151 (rdr_env, imports) <- rnImports import_decls ;
152 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
153 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
155 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
156 -- Fail if there are any errors so far
157 -- The error printing (if needed) takes advantage
158 -- of the tcg_env we have now set
161 -- Load any orphan-module interfaces, so that
162 -- their rules and instance decls will be found
163 loadOrphanModules (imp_orphs imports) ;
165 traceRn (text "rn1a") ;
166 -- Rename and type check the declarations
167 tcg_env <- tcRnSrcDecls local_decls ;
168 setGblEnv tcg_env $ do {
170 traceRn (text "rn3") ;
172 -- Report the use of any deprecated things
173 -- We do this before processsing the export list so
174 -- that we don't bleat about re-exporting a deprecated
175 -- thing (especially via 'module Foo' export item)
176 -- Only uses in the body of the module are complained about
177 reportDeprecations tcg_env ;
179 -- Process the export list
180 exports <- exportsFromAvail (isJust maybe_mod) exports ;
182 {- Jan 04: I don't think this is necessary any more; usage info is derived from tcg_dus
183 -- Get any supporting decls for the exports that have not already
184 -- been sucked in for the declarations in the body of the module.
185 -- (This can happen if something is imported only to be re-exported.)
187 -- Importing these supporting declarations is required
188 -- *only* to gether usage information
189 -- (see comments with MkIface.mkImportInfo for why)
190 -- We don't need the results, but sucking them in may side-effect
191 -- the ExternalPackageState, apart from recording usage
192 mappM (tcLookupGlobal . availName) export_avails ;
195 -- Check whether the entire module is deprecated
196 -- This happens only once per module
197 let { mod_deprecs = checkModDeprec mod_deprec } ;
199 -- Add exports and deprecations to envt
200 let { final_env = tcg_env { tcg_exports = exports,
201 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
202 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
204 -- A module deprecation over-rides the earlier ones
207 -- Report unused names
208 reportUnusedNames final_env ;
210 -- Dump output and return
217 %************************************************************************
219 The interactive interface
221 %************************************************************************
226 -> InteractiveContext
228 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
229 -- The returned [Name] is the same as the input except for
230 -- ExprStmt, in which case the returned [Name] is [itName]
232 -- The returned TypecheckedHsExpr is of type IO [ () ],
233 -- a list of the bound values, coerced to ().
235 tcRnStmt hsc_env ictxt rdr_stmt
236 = initTcPrintErrors hsc_env iNTERACTIVE $
237 setInteractiveContext ictxt $ do {
239 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
240 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
241 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
244 -- The real work is done here
245 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
247 traceTc (text "tcs 1") ;
248 let { -- Make all the bound ids "global" ids, now that
249 -- they're notionally top-level bindings. This is
250 -- important: otherwise when we come to compile an expression
251 -- using these ids later, the byte code generator will consider
252 -- the occurrences to be free rather than global.
253 global_ids = map (globaliseId VanillaGlobal) bound_ids ;
255 -- Update the interactive context
256 rn_env = ic_rn_local_env ictxt ;
257 type_env = ic_type_env ictxt ;
259 bound_names = map idName global_ids ;
260 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
262 -- Remove any shadowed bindings from the type_env;
263 -- they are inaccessible but might, I suppose, cause
264 -- a space leak if we leave them there
265 shadowed = [ n | name <- bound_names,
266 let rdr_name = mkRdrUnqual (nameOccName name),
267 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
269 filtered_type_env = delListFromNameEnv type_env shadowed ;
270 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
272 new_ic = ictxt { ic_rn_local_env = new_rn_env,
273 ic_type_env = new_type_env }
276 dumpOptTcRn Opt_D_dump_tc
277 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
278 text "Typechecked expr" <+> ppr tc_expr]) ;
280 returnM (new_ic, bound_names, tc_expr)
285 Here is the grand plan, implemented in tcUserStmt
287 What you type The IO [HValue] that hscStmt returns
288 ------------- ------------------------------------
289 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
292 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
295 expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it]
296 [NB: result not printed] bindings: [it]
298 expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it]
299 result showable) bindings: [it]
301 expr (of non-IO type,
302 result not showable) ==> error
306 ---------------------------
307 tcUserStmt :: LStmt Name -> TcM ([Id], LHsExpr Id)
308 tcUserStmt (L _ (ExprStmt expr _))
309 = newUnique `thenM` \ uniq ->
311 fresh_it = itName uniq
312 the_bind = noLoc $ FunBind (noLoc fresh_it) False
313 [ mkSimpleMatch [] expr placeHolderType ]
315 tryTcLIE_ (do { -- Try this if the other fails
316 traceTc (text "tcs 1b") ;
318 nlLetStmt [HsBindGroup (unitBag the_bind) [] NonRecursive],
319 nlExprStmt (nlHsApp (nlHsVar printName)
322 (do { -- Try this first
323 traceTc (text "tcs 1a") ;
324 tc_stmts [nlBindStmt (nlVarPat fresh_it) expr] })
326 tcUserStmt stmt = tc_stmts [stmt]
328 ---------------------------
330 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
332 ret_ty = mkListTy unitTy ;
333 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
335 names = map unLoc (collectStmtsBinders stmts) ;
337 stmt_ctxt = SC { sc_what = DoExpr,
339 sc_body = check_body,
342 check_rhs rhs rhs_ty = tcCheckRho rhs (mkTyConApp ioTyCon [rhs_ty]) ;
343 check_body body = tcCheckRho body io_ret_ty ;
345 -- mk_return builds the expression
346 -- returnIO @ [()] [coerce () x, .., coerce () z]
348 -- Despite the inconvenience of building the type applications etc,
349 -- this *has* to be done in type-annotated post-typecheck form
350 -- because we are going to return a list of *polymorphic* values
351 -- coerced to type (). If we built a *source* stmt
352 -- return [coerce x, ..., coerce z]
353 -- then the type checker would instantiate x..z, and we wouldn't
354 -- get their *polymorphic* values. (And we'd get ambiguity errs
355 -- if they were overloaded, since they aren't applied to anything.)
356 mk_return ret_id ids = nlHsApp (noLoc $ TyApp (nlHsVar ret_id) [ret_ty])
357 (noLoc $ ExplicitList unitTy (map mk_item ids)) ;
358 mk_item id = nlHsApp (noLoc $ TyApp (nlHsVar unsafeCoerceId) [idType id, unitTy])
361 io_ty = mkTyConApp ioTyCon []
364 -- OK, we're ready to typecheck the stmts
365 traceTc (text "tcs 2") ;
366 ((ids, tc_expr), lie) <- getLIE $ do {
367 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
369 -- Look up the names right in the middle,
370 -- where they will all be in scope
371 ids <- mappM tcLookupId names ;
372 ret_id <- tcLookupId returnIOName ; -- return @ IO
373 return (ids, [nlResultStmt (mk_return ret_id ids)]) } ;
375 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
376 return (ids, noLoc (HsDo DoExpr tc_stmts io_ids io_ret_ty))
379 -- Simplify the context right here, so that we fail
380 -- if there aren't enough instances. Notably, when we see
382 -- we use recoverTc_ to try it <- e
383 -- and then let it = e
384 -- It's the simplify step that rejects the first.
385 traceTc (text "tcs 3") ;
386 const_binds <- tcSimplifyInteractive lie ;
388 -- Build result expression and zonk it
389 let { expr = mkHsLet const_binds tc_expr } ;
390 zonked_expr <- zonkTopLExpr expr ;
391 zonked_ids <- zonkTopBndrs ids ;
393 -- None of the Ids should be of unboxed type, because we
394 -- cast them all to HValues in the end!
395 mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ;
397 return (zonked_ids, zonked_expr)
400 combine stmt (ids, stmts) = (ids, stmt:stmts)
401 bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"),
402 nest 2 (ppr id <+> dcolon <+> ppr (idType id))])
406 tcRnExpr just finds the type of an expression
410 -> InteractiveContext
413 tcRnExpr hsc_env ictxt rdr_expr
414 = initTcPrintErrors hsc_env iNTERACTIVE $
415 setInteractiveContext ictxt $ do {
417 (rn_expr, fvs) <- rnLExpr rdr_expr ;
420 -- Now typecheck the expression;
421 -- it might have a rank-2 type (e.g. :t runST)
422 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
423 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
424 tcSimplifyInteractive lie_top ;
426 let { all_expr_ty = mkForAllTys qtvs $
427 mkFunTys (map idType dict_ids) $
429 zonkTcType all_expr_ty
432 smpl_doc = ptext SLIT("main expression")
435 tcRnExpr just finds the kind of a type
439 -> InteractiveContext
442 tcRnType hsc_env ictxt rdr_type
443 = initTcPrintErrors hsc_env iNTERACTIVE $
444 setInteractiveContext ictxt $ do {
446 rn_type <- rnLHsType doc rdr_type ;
449 -- Now kind-check the type
450 (ty', kind) <- kcHsType rn_type ;
454 doc = ptext SLIT("In GHCi input")
459 -> InteractiveContext
461 -> IO (Maybe [(IfaceDecl, Fixity)])
462 -- Look up a RdrName and return all the TyThings it might be
463 -- A capitalised RdrName is given to us in the DataName namespace,
464 -- but we want to treat it as *both* a data constructor
465 -- *and* as a type or class constructor;
466 -- hence the call to dataTcOccs, and we return up to two results
467 tcRnThing hsc_env ictxt rdr_name
468 = initTcPrintErrors hsc_env iNTERACTIVE $
469 setInteractiveContext ictxt $ do {
471 -- If the identifier is a constructor (begins with an
472 -- upper-case letter), then we need to consider both
473 -- constructor and type class identifiers.
474 let { rdr_names = dataTcOccs rdr_name } ;
476 -- results :: [(Messages, Maybe Name)]
477 results <- mapM (tryTc . lookupOccRn) rdr_names ;
479 -- The successful lookups will be (Just name)
480 let { (warns_s, good_names) = unzip [ (msgs, name)
481 | (msgs, Just name) <- results] ;
482 errs_s = [msgs | (msgs, Nothing) <- results] } ;
484 -- Fail if nothing good happened, else add warnings
485 if null good_names then
486 -- No lookup succeeded, so
487 -- pick the first error message and report it
488 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
489 -- while the other is "X is not in scope",
490 -- we definitely want the former; but we might pick the latter
491 do { addMessages (head errs_s) ; failM }
492 else -- Add deprecation warnings
493 mapM_ addMessages warns_s ;
495 -- And lookup up the entities
496 mapM do_one good_names
499 do_one name = do { thing <- tcLookupGlobal name
500 ; fixity <- lookupFixityRn name
501 ; return (toIfaceDecl ictxt thing, fixity) }
503 toIfaceDecl :: InteractiveContext -> TyThing -> IfaceDecl
504 toIfaceDecl ictxt thing
505 = tyThingToIfaceDecl True {- Discard IdInfo -} emptyNameSet {- Show data cons -}
508 unqual = icPrintUnqual ictxt
509 ext_nm n | unqual n = LocalTop (nameOccName n) -- What a hack
510 | otherwise = ExtPkg (nameModuleName n) (nameOccName n)
515 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
516 setInteractiveContext icxt thing_inside
517 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
518 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
519 tcg_type_env = ic_type_env icxt}) $
520 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
525 %************************************************************************
527 Type-checking external-core modules
529 %************************************************************************
532 tcRnExtCore :: HscEnv
534 -> IO (Messages, Maybe ModGuts)
535 -- Nothing => some error occurred
537 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
538 -- The decls are IfaceDecls; all names are original names
539 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
541 initTc hsc_env this_mod $ do {
543 let { ldecls = map noLoc decls } ;
545 -- Deal with the type declarations; first bring their stuff
546 -- into scope, then rname them, then type check them
547 (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup ldecls) ;
549 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
550 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
553 rn_decls <- rnTyClDecls ldecls ;
556 -- Dump trace of renaming part
557 rnDump (ppr rn_decls) ;
559 -- Typecheck them all together so that
560 -- any mutually recursive types are done right
561 tcg_env <- checkNoErrs (tcTyAndClassDecls rn_decls) ;
562 -- Make the new type env available to stuff slurped from interface files
564 setGblEnv tcg_env $ do {
566 -- Now the core bindings
567 core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;
571 bndrs = bindersOfBinds core_binds ;
572 my_exports = mkNameSet (map idName bndrs) ;
573 -- ToDo: export the data types also?
575 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
577 mod_guts = ModGuts { mg_module = this_mod,
578 mg_usages = [], -- ToDo: compute usage
579 mg_dir_imps = [], -- ??
580 mg_deps = noDependencies, -- ??
581 mg_exports = my_exports,
582 mg_types = final_type_env,
583 mg_insts = tcg_insts tcg_env,
585 mg_binds = core_binds,
588 mg_rdr_env = emptyGlobalRdrEnv,
589 mg_fix_env = emptyFixityEnv,
590 mg_deprecs = NoDeprecs,
594 tcCoreDump mod_guts ;
599 mkFakeGroup decls -- Rather clumsy; lots of unused fields
600 = HsGroup { hs_tyclds = decls, -- This is the one we want
601 hs_valds = [], hs_fords = [],
602 hs_instds = [], hs_fixds = [], hs_depds = [],
603 hs_ruleds = [], hs_defds = [] }
607 %************************************************************************
609 Type-checking the top level of a module
611 %************************************************************************
614 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
615 -- Returns the variables free in the decls
616 -- Reason: solely to report unused imports and bindings
618 = do { -- Do all the declarations
619 (tc_envs, lie) <- getLIE (tc_rn_src_decls decls) ;
621 -- tcSimplifyTop deals with constant or ambiguous InstIds.
622 -- How could there be ambiguous ones? They can only arise if a
623 -- top-level decl falls under the monomorphism
624 -- restriction, and no subsequent decl instantiates its
625 -- type. (Usually, ambiguous type variables are resolved
626 -- during the generalisation step.)
627 traceTc (text "Tc8") ;
628 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
629 -- Setting the global env exposes the instances to tcSimplifyTop
630 -- Setting the local env exposes the local Ids to tcSimplifyTop,
631 -- so that we get better error messages (monomorphism restriction)
633 -- Backsubstitution. This must be done last.
634 -- Even tcSimplifyTop may do some unification.
635 traceTc (text "Tc9") ;
636 let { (tcg_env, _) = tc_envs ;
637 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
638 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
640 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
643 let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
645 -- Make the new type env available to stuff slurped from interface files
646 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
648 return (tcg_env { tcg_type_env = final_type_env,
649 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' })
652 tc_rn_src_decls :: [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
653 -- Loops around dealing with each top level inter-splice group
654 -- in turn, until it's dealt with the entire module
656 = do { let { (first_group, group_tail) = findSplice ds } ;
657 -- If ds is [] we get ([], Nothing)
659 -- Type check the decls up to, but not including, the first splice
660 tc_envs@(tcg_env,tcl_env) <- tcRnGroup first_group ;
662 -- Bale out if errors; for example, error recovery when checking
663 -- the RHS of 'main' can mean that 'main' is not in the envt for
664 -- the subsequent checkMain test
669 -- If there is no splice, we're nearly done
671 Nothing -> do { -- Last thing: check for `main'
672 tcg_env <- checkMain ;
673 return (tcg_env, tcl_env)
676 -- If there's a splice, we must carry on
677 Just (SpliceDecl splice_expr, rest_ds) -> do {
679 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
682 -- Rename the splice expression, and get its supporting decls
683 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
684 failIfErrsM ; -- Don't typecheck if renaming failed
686 -- Execute the splice
687 spliced_decls <- tcSpliceDecls rn_splice_expr ;
689 -- Glue them on the front of the remaining decls and loop
690 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
691 tc_rn_src_decls (spliced_decls ++ rest_ds)
697 %************************************************************************
699 Type-checking the top level of a module
701 %************************************************************************
703 tcRnGroup takes a bunch of top-level source-code declarations, and
705 * gets supporting declarations from interface files
708 * and augments the TcGblEnv with the results
710 In Template Haskell it may be called repeatedly for each group of
711 declarations. It expects there to be an incoming TcGblEnv in the
712 monad; it augments it and returns the new TcGblEnv.
715 tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
716 -- Returns the variables free in the decls, for unused-binding reporting
718 = do { -- Rename the declarations
719 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
720 setGblEnv tcg_env $ do {
722 -- Typecheck the declarations
723 tcTopSrcDecls rn_decls
726 ------------------------------------------------
727 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
729 = do { -- Bring top level binders into scope
730 (rdr_env, imports) <- importsFromLocalDecls group ;
731 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
732 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
735 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
736 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
738 -- Rename the source decls
739 (tcg_env, rn_decls) <- rnSrcDecls group ;
742 -- Dump trace of renaming part
743 rnDump (ppr rn_decls) ;
745 return (tcg_env, rn_decls)
748 ------------------------------------------------
749 tcTopSrcDecls :: HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
751 (HsGroup { hs_tyclds = tycl_decls,
752 hs_instds = inst_decls,
753 hs_fords = foreign_decls,
754 hs_defds = default_decls,
755 hs_ruleds = rule_decls,
756 hs_valds = val_binds })
757 = do { -- Type-check the type and class decls, and all imported decls
758 -- The latter come in via tycl_decls
759 traceTc (text "Tc2") ;
761 tcg_env <- checkNoErrs (tcTyAndClassDecls tycl_decls) ;
762 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
763 -- an error we'd better stop now, to avoid a cascade
765 -- Make these type and class decls available to stuff slurped from interface files
766 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
769 setGblEnv tcg_env $ do {
770 -- Source-language instances, including derivings,
771 -- and import the supporting declarations
772 traceTc (text "Tc3") ;
773 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
774 setGblEnv tcg_env $ do {
776 -- Foreign import declarations next. No zonking necessary
777 -- here; we can tuck them straight into the global environment.
778 traceTc (text "Tc4") ;
779 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
780 tcExtendGlobalValEnv fi_ids $ do {
782 -- Default declarations
783 traceTc (text "Tc4a") ;
784 default_tys <- tcDefaults default_decls ;
785 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
787 -- Value declarations next
788 -- We also typecheck any extra binds that came out
789 -- of the "deriving" process (deriv_binds)
790 traceTc (text "Tc5") ;
791 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
792 setLclTypeEnv lcl_env $ do {
794 -- Second pass over class and instance declarations,
795 traceTc (text "Tc6") ;
796 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
797 showLIE (text "after instDecls2") ;
800 -- They need to be zonked, so we return them
801 traceTc (text "Tc7") ;
802 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
805 rules <- tcRules rule_decls ;
808 traceTc (text "Tc7a") ;
809 tcg_env <- getGblEnv ;
810 let { all_binds = tc_val_binds `unionBags`
811 inst_binds `unionBags`
814 -- Extend the GblEnv with the (as yet un-zonked)
815 -- bindings, rules, foreign decls
816 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
817 tcg_rules = tcg_rules tcg_env ++ rules,
818 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
819 return (tcg_env', lcl_env)
824 %*********************************************************
826 mkGlobalContext: make up an interactive context
828 Used for initialising the lexical environment
829 of the interactive read-eval-print loop
831 %*********************************************************
835 mkExportEnv :: HscEnv -> [ModuleName] -- Expose these modules' exports only
838 mkExportEnv hsc_env exports
839 = do { mb_envs <- initTcPrintErrors hsc_env iNTERACTIVE $
840 mappM getModuleExports exports
842 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
843 Nothing -> return emptyGlobalRdrEnv
844 -- Some error; initTc will have printed it
847 getModuleExports :: ModuleName -> TcM GlobalRdrEnv
849 = do { iface <- load_iface mod
850 ; avails <- exportsToAvails (mi_exports iface)
851 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
852 | avail <- avails, name <- availNames avail ] }
853 ; returnM (mkGlobalRdrEnv gres) }
855 vanillaProv :: ModuleName -> Provenance
856 -- We're building a GlobalRdrEnv as if the user imported
857 -- all the specified modules into the global interactive module
858 vanillaProv mod = Imported [ImportSpec mod mod False
859 (srcLocSpan interactiveSrcLoc)] False
865 -> InteractiveContext
866 -> ModuleName -- Module to inspect
867 -> Bool -- Grab just the exports, or the whole toplev
868 -> IO (Maybe [IfaceDecl])
870 getModuleContents hsc_env ictxt mod exports_only
871 = initTcPrintErrors hsc_env iNTERACTIVE (get_mod_contents exports_only)
873 get_mod_contents exports_only
874 | not exports_only -- We want the whole top-level type env
875 -- so it had better be a home module
877 ; case lookupModuleEnvByName hpt mod of
878 Just mod_info -> return (map (toIfaceDecl ictxt) $
881 md_types (hm_details mod_info))
882 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
883 -- This is a system error; the module should be in the HPT
886 | otherwise -- Want the exports only
887 = do { iface <- load_iface mod
888 ; avails <- exportsToAvails (mi_exports iface)
889 ; mappM get_decl avails
893 = do { thing <- tcLookupGlobal (availName avail)
894 ; return (filter_decl (availOccs avail) (toIfaceDecl ictxt thing)) }
896 ---------------------
897 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
898 = decl { ifSigs = filter (keep_sig occs) sigs }
899 filter_decl occs decl@(IfaceData {ifCons = IfDataTyCon cons})
900 = decl { ifCons = IfDataTyCon (filter (keep_con occs) cons) }
901 filter_decl occs decl@(IfaceData {ifCons = IfNewTyCon con})
902 | keep_con occs con = decl
903 | otherwise = decl {ifCons = IfAbstractTyCon} -- Hmm?
904 filter_decl occs decl
907 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
908 keep_con occs (IfaceConDecl occ _ _ _ _ _) = occ `elem` occs
910 availOccs avail = map nameOccName (availNames avail)
912 wantToSee (AnId id) = not (isImplicitId id)
913 wantToSee (ADataCon _) = False -- They'll come via their TyCon
916 ---------------------
917 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
919 doc = ptext SLIT("context for compiling statements")
921 ---------------------
922 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
927 %************************************************************************
931 %************************************************************************
935 = do { ghci_mode <- getGhciMode ;
936 tcg_env <- getGblEnv ;
938 mb_main_mod <- readMutVar v_MainModIs ;
939 mb_main_fn <- readMutVar v_MainFunIs ;
940 let { main_mod = case mb_main_mod of {
941 Just mod -> mkModuleName mod ;
942 Nothing -> mAIN_Name } ;
943 main_fn = case mb_main_fn of {
944 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
945 Nothing -> main_RDR_Unqual } } ;
947 check_main ghci_mode tcg_env main_mod main_fn
951 check_main ghci_mode tcg_env main_mod main_fn
952 -- If we are in module Main, check that 'main' is defined.
953 -- It may be imported from another module!
955 -- ToDo: We have to return the main_name separately, because it's a
956 -- bona fide 'use', and should be recorded as such, but the others
959 -- Blimey: a whole page of code to do this...
960 | mod_name /= main_mod
964 = addErrCtxt mainCtxt $
965 do { mb_main <- lookupSrcOcc_maybe main_fn
966 -- Check that 'main' is in scope
967 -- It might be imported from another module!
969 Nothing -> do { complain_no_main
972 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
973 -- :Main.main :: IO () = runIO main
975 ; (main_expr, ty) <- addSrcSpan (srcLocSpan (getSrcLoc main_name)) $
978 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
979 main_bind = noLoc (VarBind root_main_id main_expr) }
981 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
983 tcg_dus = tcg_dus tcg_env
984 `plusDU` usesOnly (unitFV main_name)
988 mod_name = moduleName (tcg_mod tcg_env)
990 complain_no_main | ghci_mode == Interactive = return ()
991 | otherwise = failWithTc noMainMsg
992 -- In interactive mode, don't worry about the absence of 'main'
993 -- In other modes, fail altogether, so that we don't go on
994 -- and complain a second time when processing the export list.
996 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
997 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
998 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
1002 %************************************************************************
1006 %************************************************************************
1009 rnDump :: SDoc -> TcRn ()
1010 -- Dump, with a banner, if -ddump-rn
1011 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
1013 tcDump :: TcGblEnv -> TcRn ()
1015 = do { dflags <- getDOpts ;
1017 -- Dump short output if -ddump-types or -ddump-tc
1018 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1019 (dumpTcRn short_dump) ;
1021 -- Dump bindings if -ddump-tc
1022 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1025 short_dump = pprTcGblEnv env
1026 full_dump = pprLHsBinds (tcg_binds env)
1027 -- NB: foreign x-d's have undefined's in their types;
1028 -- hence can't show the tc_fords
1031 = do { dflags <- getDOpts ;
1032 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1033 (dumpTcRn (pprModGuts mod_guts)) ;
1035 -- Dump bindings if -ddump-tc
1036 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1038 full_dump = pprCoreBindings (mg_binds mod_guts)
1040 -- It's unpleasant having both pprModGuts and pprModDetails here
1041 pprTcGblEnv :: TcGblEnv -> SDoc
1042 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1043 tcg_insts = dfun_ids,
1045 tcg_imports = imports })
1046 = vcat [ ppr_types dfun_ids type_env
1047 , ppr_insts dfun_ids
1048 , vcat (map ppr rules)
1049 , ppr_gen_tycons (typeEnvTyCons type_env)
1050 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1051 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1053 pprModGuts :: ModGuts -> SDoc
1054 pprModGuts (ModGuts { mg_types = type_env,
1056 = vcat [ ppr_types [] type_env,
1060 ppr_types :: [Var] -> TypeEnv -> SDoc
1061 ppr_types dfun_ids type_env
1062 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1064 ids = [id | id <- typeEnvIds type_env, want_sig id]
1065 want_sig id | opt_PprStyle_Debug = True
1066 | otherwise = isLocalId id &&
1067 isExternalName (idName id) &&
1068 not (id `elem` dfun_ids)
1069 -- isLocalId ignores data constructors, records selectors etc.
1070 -- The isExternalName ignores local dictionary and method bindings
1071 -- that the type checker has invented. Top-level user-defined things
1072 -- have External names.
1074 ppr_insts :: [Var] -> SDoc
1075 ppr_insts [] = empty
1076 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1078 ppr_sigs :: [Var] -> SDoc
1080 -- Print type signatures; sort by OccName
1081 = vcat (map ppr_sig (sortLt lt_sig ids))
1083 lt_sig id1 id2 = getOccName id1 < getOccName id2
1084 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1086 ppr_rules :: [IdCoreRule] -> SDoc
1087 ppr_rules [] = empty
1088 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1089 nest 4 (pprIdRules rs),
1092 ppr_gen_tycons [] = empty
1093 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1094 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]