2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
9 mkExportEnv, getModuleContents, tcRnStmt, tcRnThing, tcRnExpr,
16 #include "HsVersions.h"
19 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
22 import CmdLineOpts ( DynFlag(..), opt_PprStyle_Debug, dopt )
23 import DriverState ( v_MainModIs, v_MainFunIs )
25 import RdrHsSyn ( findSplice )
27 import PrelNames ( runIOName, rootMainName, mAIN_Name,
29 import RdrName ( RdrName, mkRdrUnqual, emptyGlobalRdrEnv,
31 import TcHsSyn ( zonkTopDecls )
32 import TcExpr ( tcInferRho )
34 import TcType ( tidyTopType )
35 import Inst ( showLIE )
36 import TcBinds ( tcTopBinds )
37 import TcDefaults ( tcDefaults )
38 import TcEnv ( tcExtendGlobalValEnv, tcLookupGlobal )
39 import TcRules ( tcRules )
40 import TcForeign ( tcForeignImports, tcForeignExports )
41 import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
42 import TcIface ( tcExtCoreBindings )
43 import TcSimplify ( tcSimplifyTop )
44 import TcTyClsDecls ( tcTyAndClassDecls )
45 import LoadIface ( loadOrphanModules )
46 import RnNames ( importsFromLocalDecls, rnImports, exportsFromAvail,
47 reportUnusedNames, reportDeprecations )
48 import RnEnv ( lookupSrcOcc_maybe )
49 import RnSource ( rnSrcDecls, rnTyClDecls, checkModDeprec )
50 import PprCore ( pprIdRules, pprCoreBindings )
51 import CoreSyn ( IdCoreRule, bindersOfBinds )
52 import ErrUtils ( Messages, mkDumpDoc, showPass )
53 import Id ( mkExportedLocalId, isLocalId, idName, idType )
55 import Module ( mkHomeModule, mkModuleName, moduleName, moduleEnvElts )
56 import OccName ( mkVarOcc )
57 import Name ( Name, isExternalName, getSrcLoc, getOccName )
59 import TyCon ( tyConHasGenerics )
60 import SrcLoc ( srcLocSpan, Located(..), noLoc )
62 import HscTypes ( ModGuts(..), HscEnv(..),
63 GhciMode(..), noDependencies,
64 Deprecs( NoDeprecs ), plusDeprecs,
65 GenAvailInfo(Avail), availsToNameSet, availName,
66 ForeignStubs(NoStubs), TypeEnv, typeEnvTyCons,
67 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
71 import HsSyn ( HsStmtContext(..),
73 collectStmtsBinders, mkSimpleMatch, placeHolderType )
74 import RdrName ( GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
75 Provenance(..), ImportSpec(..),
76 lookupLocalRdrEnv, extendLocalRdrEnv )
77 import RnSource ( addTcgDUs )
78 import TcHsSyn ( mkHsLet, zonkTopLExpr, zonkTopBndrs )
79 import TcExpr ( tcCheckRho )
80 import TcMType ( zonkTcType )
81 import TcMatches ( tcStmtsAndThen, TcStmtCtxt(..) )
82 import TcSimplify ( tcSimplifyInteractive, tcSimplifyInfer )
83 import TcType ( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType )
84 import TcEnv ( tcLookupTyCon, tcLookupId )
85 import TyCon ( DataConDetails(..) )
86 import Inst ( tcStdSyntaxName )
87 import RnExpr ( rnStmts, rnLExpr )
88 import RnNames ( exportsToAvails )
89 import LoadIface ( loadSrcInterface )
90 import IfaceSyn ( IfaceDecl(..), IfaceClassOp(..), IfaceConDecl(..), 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 ( globaliseId )
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 (Messages, 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 exports <- exportsFromAvail (isJust maybe_mod) exports ;
177 {- Jan 04: I don't think this is necessary any more; usage info is derived from tcg_dus
178 -- Get any supporting decls for the exports that have not already
179 -- been sucked in for the declarations in the body of the module.
180 -- (This can happen if something is imported only to be re-exported.)
182 -- Importing these supporting declarations is required
183 -- *only* to gether usage information
184 -- (see comments with MkIface.mkImportInfo for why)
185 -- We don't need the results, but sucking them in may side-effect
186 -- the ExternalPackageState, apart from recording usage
187 mappM (tcLookupGlobal . availName) export_avails ;
190 -- Check whether the entire module is deprecated
191 -- This happens only once per module
192 let { mod_deprecs = checkModDeprec mod_deprec } ;
194 -- Add exports and deprecations to envt
195 let { final_env = tcg_env { tcg_exports = exports,
196 tcg_dus = tcg_dus tcg_env `plusDU` usesOnly exports,
197 tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs`
199 -- A module deprecation over-rides the earlier ones
202 -- Report unused names
203 reportUnusedNames final_env ;
205 -- Dump output and return
212 %************************************************************************
214 The interactive interface
216 %************************************************************************
221 -> InteractiveContext
223 -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id))
224 -- The returned [Name] is the same as the input except for
225 -- ExprStmt, in which case the returned [Name] is [itName]
227 -- The returned TypecheckedHsExpr is of type IO [ () ],
228 -- a list of the bound values, coerced to ().
230 tcRnStmt hsc_env ictxt rdr_stmt
231 = initTcPrintErrors hsc_env iNTERACTIVE $
232 setInteractiveContext ictxt $ do {
234 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
235 ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
236 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
239 -- The real work is done here
240 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
242 traceTc (text "tcs 1") ;
243 let { -- Make all the bound ids "global" ids, now that
244 -- they're notionally top-level bindings. This is
245 -- important: otherwise when we come to compile an expression
246 -- using these ids later, the byte code generator will consider
247 -- the occurrences to be free rather than global.
248 global_ids = map (globaliseId VanillaGlobal) bound_ids ;
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 = initTcPrintErrors 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 = initTcPrintErrors 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 -} emptyNameSet {- Show data cons -}
476 unqual = icPrintUnqual ictxt
477 ext_nm n | unqual n = LocalTop (nameOccName n) -- What a hack
478 | otherwise = ExtPkg (nameModuleName n) (nameOccName n)
483 setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
484 setInteractiveContext icxt thing_inside
485 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
486 (updGblEnv (\env -> env {tcg_rdr_env = ic_rn_gbl_env icxt,
487 tcg_type_env = ic_type_env icxt}) $
488 updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt}) $
493 %************************************************************************
495 Type-checking external-core modules
497 %************************************************************************
500 tcRnExtCore :: HscEnv
502 -> IO (Messages, Maybe ModGuts)
503 -- Nothing => some error occurred
505 tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
506 -- The decls are IfaceDecls; all names are original names
507 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
509 initTc hsc_env this_mod $ do {
511 let { ldecls = map noLoc decls } ;
513 -- Deal with the type declarations; first bring their stuff
514 -- into scope, then rname them, then type check them
515 (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup ldecls) ;
517 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
518 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
521 rn_decls <- rnTyClDecls ldecls ;
524 -- Dump trace of renaming part
525 rnDump (ppr rn_decls) ;
527 -- Typecheck them all together so that
528 -- any mutually recursive types are done right
529 tcg_env <- checkNoErrs (tcTyAndClassDecls rn_decls) ;
530 -- Make the new type env available to stuff slurped from interface files
532 setGblEnv tcg_env $ do {
534 -- Now the core bindings
535 core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;
539 bndrs = bindersOfBinds core_binds ;
540 my_exports = mkNameSet (map idName bndrs) ;
541 -- ToDo: export the data types also?
543 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
545 mod_guts = ModGuts { mg_module = this_mod,
546 mg_usages = [], -- ToDo: compute usage
547 mg_dir_imps = [], -- ??
548 mg_deps = noDependencies, -- ??
549 mg_exports = my_exports,
550 mg_types = final_type_env,
551 mg_insts = tcg_insts tcg_env,
553 mg_binds = core_binds,
556 mg_rdr_env = emptyGlobalRdrEnv,
557 mg_fix_env = emptyFixityEnv,
558 mg_deprecs = NoDeprecs,
562 tcCoreDump mod_guts ;
567 mkFakeGroup decls -- Rather clumsy; lots of unused fields
568 = HsGroup { hs_tyclds = decls, -- This is the one we want
569 hs_valds = [], hs_fords = [],
570 hs_instds = [], hs_fixds = [], hs_depds = [],
571 hs_ruleds = [], hs_defds = [] }
575 %************************************************************************
577 Type-checking the top level of a module
579 %************************************************************************
582 tcRnSrcDecls :: [LHsDecl RdrName] -> TcM TcGblEnv
583 -- Returns the variables free in the decls
584 -- Reason: solely to report unused imports and bindings
586 = do { -- Do all the declarations
587 (tc_envs, lie) <- getLIE (tc_rn_src_decls decls) ;
589 -- tcSimplifyTop deals with constant or ambiguous InstIds.
590 -- How could there be ambiguous ones? They can only arise if a
591 -- top-level decl falls under the monomorphism
592 -- restriction, and no subsequent decl instantiates its
593 -- type. (Usually, ambiguous type variables are resolved
594 -- during the generalisation step.)
595 traceTc (text "Tc8") ;
596 inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
597 -- Setting the global env exposes the instances to tcSimplifyTop
598 -- Setting the local env exposes the local Ids to tcSimplifyTop,
599 -- so that we get better error messages (monomorphism restriction)
601 -- Backsubstitution. This must be done last.
602 -- Even tcSimplifyTop may do some unification.
603 traceTc (text "Tc9") ;
604 let { (tcg_env, _) = tc_envs ;
605 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
606 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
608 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `unionBags` inst_binds)
611 let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
613 -- Make the new type env available to stuff slurped from interface files
614 writeMutVar (tcg_type_env_var tcg_env) final_type_env ;
616 return (tcg_env { tcg_type_env = final_type_env,
617 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' })
620 tc_rn_src_decls :: [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv)
621 -- Loops around dealing with each top level inter-splice group
622 -- in turn, until it's dealt with the entire module
624 = do { let { (first_group, group_tail) = findSplice ds } ;
625 -- If ds is [] we get ([], Nothing)
627 -- Type check the decls up to, but not including, the first splice
628 tc_envs@(tcg_env,tcl_env) <- tcRnGroup first_group ;
630 -- Bale out if errors; for example, error recovery when checking
631 -- the RHS of 'main' can mean that 'main' is not in the envt for
632 -- the subsequent checkMain test
637 -- If there is no splice, we're nearly done
639 Nothing -> do { -- Last thing: check for `main'
640 tcg_env <- checkMain ;
641 return (tcg_env, tcl_env)
644 -- If there's a splice, we must carry on
645 Just (SpliceDecl splice_expr, rest_ds) -> do {
647 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
650 -- Rename the splice expression, and get its supporting decls
651 (rn_splice_expr, splice_fvs) <- rnLExpr splice_expr ;
652 failIfErrsM ; -- Don't typecheck if renaming failed
654 -- Execute the splice
655 spliced_decls <- tcSpliceDecls rn_splice_expr ;
657 -- Glue them on the front of the remaining decls and loop
658 setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
659 tc_rn_src_decls (spliced_decls ++ rest_ds)
665 %************************************************************************
667 Type-checking the top level of a module
669 %************************************************************************
671 tcRnGroup takes a bunch of top-level source-code declarations, and
673 * gets supporting declarations from interface files
676 * and augments the TcGblEnv with the results
678 In Template Haskell it may be called repeatedly for each group of
679 declarations. It expects there to be an incoming TcGblEnv in the
680 monad; it augments it and returns the new TcGblEnv.
683 tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
684 -- Returns the variables free in the decls, for unused-binding reporting
686 = do { -- Rename the declarations
687 (tcg_env, rn_decls) <- rnTopSrcDecls decls ;
688 setGblEnv tcg_env $ do {
690 -- Typecheck the declarations
691 tcTopSrcDecls rn_decls
694 ------------------------------------------------
695 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
697 = do { -- Bring top level binders into scope
698 (rdr_env, imports) <- importsFromLocalDecls group ;
699 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
700 tcg_imports = imports `plusImportAvails` tcg_imports gbl })
703 traceRn (ptext SLIT("rnTopSrcDecls") <+> ppr rdr_env) ;
704 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
706 -- Rename the source decls
707 (tcg_env, rn_decls) <- rnSrcDecls group ;
710 -- Dump trace of renaming part
711 rnDump (ppr rn_decls) ;
713 return (tcg_env, rn_decls)
716 ------------------------------------------------
717 tcTopSrcDecls :: HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
719 (HsGroup { hs_tyclds = tycl_decls,
720 hs_instds = inst_decls,
721 hs_fords = foreign_decls,
722 hs_defds = default_decls,
723 hs_ruleds = rule_decls,
724 hs_valds = val_binds })
725 = do { -- Type-check the type and class decls, and all imported decls
726 -- The latter come in via tycl_decls
727 traceTc (text "Tc2") ;
729 tcg_env <- checkNoErrs (tcTyAndClassDecls tycl_decls) ;
730 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
731 -- an error we'd better stop now, to avoid a cascade
733 -- Make these type and class decls available to stuff slurped from interface files
734 writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;
737 setGblEnv tcg_env $ do {
738 -- Source-language instances, including derivings,
739 -- and import the supporting declarations
740 traceTc (text "Tc3") ;
741 (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
742 setGblEnv tcg_env $ do {
744 -- Foreign import declarations next. No zonking necessary
745 -- here; we can tuck them straight into the global environment.
746 traceTc (text "Tc4") ;
747 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
748 tcExtendGlobalValEnv fi_ids $ do {
750 -- Default declarations
751 traceTc (text "Tc4a") ;
752 default_tys <- tcDefaults default_decls ;
753 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
755 -- Value declarations next
756 -- We also typecheck any extra binds that came out
757 -- of the "deriving" process (deriv_binds)
758 traceTc (text "Tc5") ;
759 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds ++ deriv_binds) ;
760 setLclTypeEnv lcl_env $ do {
762 -- Second pass over class and instance declarations,
763 traceTc (text "Tc6") ;
764 (tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
765 showLIE (text "after instDecls2") ;
768 -- They need to be zonked, so we return them
769 traceTc (text "Tc7") ;
770 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
773 rules <- tcRules rule_decls ;
776 traceTc (text "Tc7a") ;
777 tcg_env <- getGblEnv ;
778 let { all_binds = tc_val_binds `unionBags`
779 inst_binds `unionBags`
782 -- Extend the GblEnv with the (as yet un-zonked)
783 -- bindings, rules, foreign decls
784 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds,
785 tcg_rules = tcg_rules tcg_env ++ rules,
786 tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
787 return (tcg_env', lcl_env)
792 %*********************************************************
794 mkGlobalContext: make up an interactive context
796 Used for initialising the lexical environment
797 of the interactive read-eval-print loop
799 %*********************************************************
803 mkExportEnv :: HscEnv -> [ModuleName] -- Expose these modules' exports only
806 mkExportEnv hsc_env exports
807 = do { mb_envs <- initTcPrintErrors hsc_env iNTERACTIVE $
808 mappM getModuleExports exports
810 Just envs -> return (foldr plusGlobalRdrEnv emptyGlobalRdrEnv envs)
811 Nothing -> return emptyGlobalRdrEnv
812 -- Some error; initTc will have printed it
815 getModuleExports :: ModuleName -> TcM GlobalRdrEnv
817 = do { iface <- load_iface mod
818 ; avails <- exportsToAvails (mi_exports iface)
819 ; let { gres = [ GRE { gre_name = name, gre_prov = vanillaProv mod }
820 | avail <- avails, name <- availNames avail ] }
821 ; returnM (mkGlobalRdrEnv gres) }
823 vanillaProv :: ModuleName -> Provenance
824 -- We're building a GlobalRdrEnv as if the user imported
825 -- all the specified modules into the global interactive module
826 vanillaProv mod = Imported [ImportSpec mod mod False
827 (srcLocSpan interactiveSrcLoc)] False
833 -> InteractiveContext
834 -> ModuleName -- Module to inspect
835 -> Bool -- Grab just the exports, or the whole toplev
836 -> IO (Maybe [IfaceDecl])
838 getModuleContents hsc_env ictxt mod exports_only
839 = initTcPrintErrors hsc_env iNTERACTIVE (get_mod_contents exports_only)
841 get_mod_contents exports_only
842 | not exports_only -- We want the whole top-level type env
843 -- so it had better be a home module
845 ; case lookupModuleEnvByName hpt mod of
846 Just mod_info -> return (map (toIfaceDecl ictxt) $
849 md_types (hm_details mod_info))
850 Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
851 -- This is a system error; the module should be in the HPT
854 | otherwise -- Want the exports only
855 = do { iface <- load_iface mod
856 ; avails <- exportsToAvails (mi_exports iface)
857 ; mappM get_decl avails
861 = do { thing <- tcLookupGlobal (availName avail)
862 ; return (filter_decl (availOccs avail) (toIfaceDecl ictxt thing)) }
864 ---------------------
865 filter_decl occs decl@(IfaceClass {ifSigs = sigs})
866 = decl { ifSigs = filter (keep_sig occs) sigs }
867 filter_decl occs decl@(IfaceData {ifCons = DataCons cons})
868 = decl { ifCons = DataCons (filter (keep_con occs) cons) }
869 filter_decl occs decl
872 keep_sig occs (IfaceClassOp occ _ _) = occ `elem` occs
873 keep_con occs (IfaceConDecl occ _ _ _ _ _) = occ `elem` occs
875 availOccs avail = map nameOccName (availNames avail)
877 wantToSee (AnId id) = not (isImplicitId id)
878 wantToSee (ADataCon _) = False -- They'll come via their TyCon
881 ---------------------
882 load_iface mod = loadSrcInterface doc mod False {- Not boot iface -}
884 doc = ptext SLIT("context for compiling statements")
886 ---------------------
887 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
892 %************************************************************************
896 %************************************************************************
900 = do { ghci_mode <- getGhciMode ;
901 tcg_env <- getGblEnv ;
903 mb_main_mod <- readMutVar v_MainModIs ;
904 mb_main_fn <- readMutVar v_MainFunIs ;
905 let { main_mod = case mb_main_mod of {
906 Just mod -> mkModuleName mod ;
907 Nothing -> mAIN_Name } ;
908 main_fn = case mb_main_fn of {
909 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
910 Nothing -> main_RDR_Unqual } } ;
912 check_main ghci_mode tcg_env main_mod main_fn
916 check_main ghci_mode tcg_env main_mod main_fn
917 -- If we are in module Main, check that 'main' is defined.
918 -- It may be imported from another module!
920 -- ToDo: We have to return the main_name separately, because it's a
921 -- bona fide 'use', and should be recorded as such, but the others
924 -- Blimey: a whole page of code to do this...
925 | mod_name /= main_mod
929 = addErrCtxt mainCtxt $
930 do { mb_main <- lookupSrcOcc_maybe main_fn
931 -- Check that 'main' is in scope
932 -- It might be imported from another module!
934 Nothing -> do { complain_no_main
937 { let { rhs = nlHsApp (nlHsVar runIOName) (nlHsVar main_name) }
938 -- :Main.main :: IO () = runIO main
940 ; (main_expr, ty) <- addSrcSpan (srcLocSpan (getSrcLoc main_name)) $
943 ; let { root_main_id = mkExportedLocalId rootMainName ty ;
944 main_bind = noLoc (VarBind root_main_id main_expr) }
946 ; return (tcg_env { tcg_binds = tcg_binds tcg_env
948 tcg_dus = tcg_dus tcg_env
949 `plusDU` usesOnly (unitFV main_name)
953 mod_name = moduleName (tcg_mod tcg_env)
955 complain_no_main | ghci_mode == Interactive = return ()
956 | otherwise = failWithTc noMainMsg
957 -- In interactive mode, don't worry about the absence of 'main'
958 -- In other modes, fail altogether, so that we don't go on
959 -- and complain a second time when processing the export list.
961 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
962 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
963 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
967 %************************************************************************
971 %************************************************************************
974 rnDump :: SDoc -> TcRn ()
975 -- Dump, with a banner, if -ddump-rn
976 rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
978 tcDump :: TcGblEnv -> TcRn ()
980 = do { dflags <- getDOpts ;
982 -- Dump short output if -ddump-types or -ddump-tc
983 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
984 (dumpTcRn short_dump) ;
986 -- Dump bindings if -ddump-tc
987 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
990 short_dump = pprTcGblEnv env
991 full_dump = ppr (tcg_binds env)
992 -- NB: foreign x-d's have undefined's in their types;
993 -- hence can't show the tc_fords
996 = do { dflags <- getDOpts ;
997 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
998 (dumpTcRn (pprModGuts mod_guts)) ;
1000 -- Dump bindings if -ddump-tc
1001 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1003 full_dump = pprCoreBindings (mg_binds mod_guts)
1005 -- It's unpleasant having both pprModGuts and pprModDetails here
1006 pprTcGblEnv :: TcGblEnv -> SDoc
1007 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1008 tcg_insts = dfun_ids,
1010 tcg_imports = imports })
1011 = vcat [ ppr_types dfun_ids type_env
1012 , ppr_insts dfun_ids
1013 , vcat (map ppr rules)
1014 , ppr_gen_tycons (typeEnvTyCons type_env)
1015 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1016 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1018 pprModGuts :: ModGuts -> SDoc
1019 pprModGuts (ModGuts { mg_types = type_env,
1021 = vcat [ ppr_types [] type_env,
1025 ppr_types :: [Var] -> TypeEnv -> SDoc
1026 ppr_types dfun_ids type_env
1027 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1029 ids = [id | id <- typeEnvIds type_env, want_sig id]
1030 want_sig id | opt_PprStyle_Debug = True
1031 | otherwise = isLocalId id &&
1032 isExternalName (idName id) &&
1033 not (id `elem` dfun_ids)
1034 -- isLocalId ignores data constructors, records selectors etc.
1035 -- The isExternalName ignores local dictionary and method bindings
1036 -- that the type checker has invented. Top-level user-defined things
1037 -- have External names.
1039 ppr_insts :: [Var] -> SDoc
1040 ppr_insts [] = empty
1041 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1043 ppr_sigs :: [Var] -> SDoc
1045 -- Print type signatures; sort by OccName
1046 = vcat (map ppr_sig (sortLt lt_sig ids))
1048 lt_sig id1 id2 = getOccName id1 < getOccName id2
1049 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1051 ppr_rules :: [IdCoreRule] -> SDoc
1052 ppr_rules [] = empty
1053 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1054 nest 4 (pprIdRules rs),
1057 ppr_gen_tycons [] = empty
1058 ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
1059 nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]