2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
9 mkGlobalContext, getModuleContents,
11 tcRnModule, checkOldIface,
12 importSupportingDecls, tcTopSrcDecls,
13 tcRnIface, tcRnExtCore, tcRnStmt, tcRnExpr, tcRnThing
16 #include "HsVersions.h"
19 import {-# SOURCE #-} TcSplice( tcSpliceDecls )
22 import CmdLineOpts ( DynFlag(..), opt_PprStyle_Debug, dopt )
23 import HsSyn ( HsModule(..), HsBinds(..), MonoBinds(..), HsDecl(..), HsExpr(..),
24 Stmt(..), Pat(VarPat), HsStmtContext(..), RuleDecl(..),
25 HsGroup(..), SpliceDecl(..),
26 mkSimpleMatch, placeHolderType, toHsType, andMonoBinds,
27 isSrcRule, collectStmtsBinders
29 import RdrHsSyn ( RdrNameHsModule, RdrNameHsDecl, RdrNameStmt, RdrNameHsExpr,
30 emptyGroup, mkGroup, findSplice, addImpDecls )
32 import PrelNames ( iNTERACTIVE, ioTyConName, printName,
33 returnIOName, bindIOName, failIOName, thenIOName, runIOName,
34 dollarMainName, itName, mAIN_Name
36 import MkId ( unsafeCoerceId )
37 import RdrName ( RdrName, getRdrName, mkUnqual, mkRdrUnqual,
38 lookupRdrEnv, elemRdrEnv )
40 import RnHsSyn ( RenamedHsDecl, RenamedStmt, RenamedTyClDecl,
41 ruleDeclFVs, instDeclFVs, tyClDeclFVs )
42 import TcHsSyn ( TypecheckedHsExpr, TypecheckedRuleDecl,
43 zonkTopBinds, zonkTopDecls, mkHsLet,
44 zonkTopExpr, zonkTopBndrs
47 import TcExpr ( tcExpr_id )
49 import TcMType ( newTyVarTy, zonkTcType )
50 import TcType ( Type, liftedTypeKind,
51 tyVarsOfType, tcFunResultTy,
52 mkForAllTys, mkFunTys, mkTyConApp, tcSplitForAllTys
54 import TcMatches ( tcStmtsAndThen )
55 import Inst ( showLIE )
56 import TcBinds ( tcTopBinds )
57 import TcClassDcl ( tcClassDecls2 )
58 import TcDefaults ( tcDefaults )
59 import TcEnv ( RecTcGblEnv,
62 tcExtendInstEnv, tcExtendRules,
63 tcLookupTyCon, tcLookupGlobal,
66 import TcRules ( tcRules )
67 import TcForeign ( tcForeignImports, tcForeignExports )
68 import TcIfaceSig ( tcInterfaceSigs, tcCoreBinds )
69 import TcInstDcls ( tcInstDecls1, tcIfaceInstDecls, tcInstDecls2 )
70 import TcSimplify ( tcSimplifyTop, tcSimplifyInfer )
71 import TcTyClsDecls ( tcTyAndClassDecls )
73 import RnNames ( rnImports, exportsFromAvail, reportUnusedNames )
74 import RnIfaces ( slurpImpDecls, checkVersions, RecompileRequired, outOfDate )
75 import RnHiFiles ( readIface, loadOldIface )
76 import RnEnv ( lookupSrcName, lookupOccRn, plusGlobalRdrEnv,
77 ubiquitousNames, implicitModuleFVs, implicitStmtFVs, dataTcOccs )
78 import RnExpr ( rnStmts, rnExpr )
79 import RnNames ( importsFromLocalDecls )
80 import RnSource ( rnSrcDecls, checkModDeprec, rnStats )
82 import OccName ( varName )
83 import CoreUnfold ( unfoldingTemplate )
84 import CoreSyn ( IdCoreRule, Bind(..) )
85 import PprCore ( pprIdRules, pprCoreBindings )
86 import TysWiredIn ( mkListTy, unitTy )
87 import ErrUtils ( mkDumpDoc, showPass )
88 import Id ( Id, mkLocalId, isLocalId, idName, idType, idUnfolding, setIdLocalExported )
89 import IdInfo ( GlobalIdDetails(..) )
90 import Var ( Var, setGlobalIdDetails )
91 import Module ( Module, moduleName, moduleUserString )
92 import Name ( Name, isExternalName, getSrcLoc, nameOccName )
93 import NameEnv ( delListFromNameEnv )
95 import TyCon ( tyConGenInfo )
96 import BasicTypes ( EP(..), RecFlag(..) )
97 import SrcLoc ( noSrcLoc )
99 import HscTypes ( PersistentCompilerState(..), InteractiveContext(..),
100 ModIface, ModDetails(..), ModGuts(..),
102 ModIface(..), ModDetails(..), IfaceDecls(..),
104 Deprecations(..), plusDeprecs,
106 GenAvailInfo(Avail), availsToNameSet,
108 TypeEnv, TyThing, typeEnvTyCons,
109 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
110 extendLocalRdrEnv, emptyFixityEnv
113 import RdrName ( rdrEnvElts )
114 import RnHiFiles ( loadInterface )
115 import RnEnv ( mkGlobalRdrEnv )
116 import HscTypes ( GlobalRdrElt(..), GlobalRdrEnv, ImportReason(..), Provenance(..),
120 import Maybe ( catMaybes )
121 import Panic ( showException )
122 import List ( partition )
123 import Util ( sortLt )
128 %************************************************************************
130 Typecheck and rename a module
132 %************************************************************************
136 tcRnModule :: HscEnv -> PersistentCompilerState
138 -> IO (PersistentCompilerState, Maybe TcGblEnv)
140 tcRnModule hsc_env pcs
141 (HsModule this_mod _ exports import_decls local_decls mod_deprec loc)
142 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
144 initTc hsc_env pcs this_mod $ addSrcLoc loc $
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 = imports })
150 traceRn (text "rn1") ;
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 traceRn (text "rn1a") ;
157 -- Rename and type check the declarations
158 (tcg_env, src_fvs) <- tcRnSrcDecls local_decls ;
159 setGblEnv tcg_env $ do {
160 traceRn (text "rn2") ;
163 (tcg_env, main_fvs) <- checkMain ;
164 setGblEnv tcg_env $ do {
166 traceRn (text "rn3") ;
167 -- Check whether the entire module is deprecated
168 -- This happens only once per module
169 -- Returns the full new deprecations; a module deprecation
170 -- over-rides the earlier ones
171 let { mod_deprecs = checkModDeprec mod_deprec } ;
172 updGblEnv (\gbl -> gbl { tcg_deprecs = tcg_deprecs gbl `plusDeprecs` mod_deprecs })
175 traceRn (text "rn4") ;
176 -- Process the export list
177 export_avails <- exportsFromAvail exports ;
178 updGblEnv (\gbl -> gbl { tcg_exports = export_avails })
181 -- Get the supporting decls for the exports
182 -- This is important *only* to gether usage information
183 -- (see comments with MkIface.mkImportInfo for why)
184 -- For OneShot compilation we could just throw away the decls
185 -- but for Batch or Interactive we must put them in the type
186 -- envt because they've been removed from the holding pen
187 let { export_fvs = availsToNameSet export_avails } ;
188 tcg_env <- importSupportingDecls export_fvs ;
189 setGblEnv tcg_env $ do {
191 -- Report unused names
192 let { used_fvs = src_fvs `plusFV` main_fvs `plusFV` export_fvs } ;
193 reportUnusedNames tcg_env used_fvs ;
195 -- Dump output and return
202 %*********************************************************
204 \subsection{Closing up the interface decls}
206 %*********************************************************
208 Suppose we discover we don't need to recompile. Then we start from the
209 IfaceDecls in the ModIface, and fluff them up by sucking in all the decls they need.
213 -> PersistentCompilerState
214 -> ModIface -- Get the decls from here
215 -> IO (PersistentCompilerState, Maybe ModDetails)
216 -- Nothing <=> errors happened
217 tcRnIface hsc_env pcs
218 (ModIface {mi_module = mod, mi_decls = iface_decls})
219 = initTc hsc_env pcs mod $ do {
221 -- Get the supporting decls, and typecheck them all together
222 -- so that any mutually recursive types are done right
223 extra_decls <- slurpImpDecls needed ;
224 env <- typecheckIfaceDecls (group `addImpDecls` extra_decls) ;
226 returnM (ModDetails { md_types = tcg_type_env env,
227 md_insts = tcg_insts env,
228 md_rules = hsCoreRules (tcg_rules env)
229 -- All the rules from an interface are of the IfaceRuleOut form
232 rule_decls = dcl_rules iface_decls
233 inst_decls = dcl_insts iface_decls
234 tycl_decls = dcl_tycl iface_decls
235 group = emptyGroup { hs_ruleds = rule_decls,
236 hs_instds = inst_decls,
237 hs_tyclds = tycl_decls }
238 needed = unionManyNameSets (map ruleDeclFVs rule_decls) `unionNameSets`
239 unionManyNameSets (map instDeclFVs inst_decls) `unionNameSets`
240 unionManyNameSets (map tyClDeclFVs tycl_decls) `unionNameSets`
242 -- Data type decls with record selectors,
243 -- which may appear in the decls, need unpackCString
244 -- and friends. It's easier to just grab them right now.
246 hsCoreRules :: [TypecheckedRuleDecl] -> [IdCoreRule]
247 -- All post-typechecking Iface rules have the form IfaceRuleOut
248 hsCoreRules rules = [(id,rule) | IfaceRuleOut id rule <- rules]
252 %************************************************************************
254 The interactive interface
256 %************************************************************************
259 tcRnStmt :: HscEnv -> PersistentCompilerState
260 -> InteractiveContext
262 -> IO (PersistentCompilerState,
263 Maybe (InteractiveContext, [Name], TypecheckedHsExpr))
264 -- The returned [Id] is the same as the input except for
265 -- ExprStmt, in which case the returned [Name] is [itName]
267 tcRnStmt hsc_env pcs ictxt rdr_stmt
268 = initTc hsc_env pcs iNTERACTIVE $
269 setInteractiveContext ictxt $ do {
271 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
272 ([rn_stmt], fvs) <- initRnInteractive ictxt
273 (rnStmts DoExpr [rdr_stmt]) ;
274 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
277 -- Suck in the supporting declarations and typecheck them
278 tcg_env <- importSupportingDecls (fvs `plusFV` implicitStmtFVs fvs) ;
279 -- NB: an earlier version deleted (rdrEnvElts local_env) from
280 -- the fvs. But (a) that isn't necessary, because previously
281 -- bound things in the local_env will be in the TypeEnv, and
282 -- the renamer doesn't re-slurp such things, and
283 -- (b) it's WRONG to delete them. Consider in GHCi:
284 -- Mod> let x = e :: T
285 -- Mod> let y = x + 3
286 -- We need to pass 'x' among the fvs to slurpImpDecls, so that
287 -- the latter can see that T is a gate, and hence import the Num T
288 -- instance decl. (See the InTypEnv case in RnIfaces.slurpSourceRefs.)
289 setGblEnv tcg_env $ do {
291 -- The real work is done here
292 ((bound_ids, tc_expr), lie) <- getLIE (tcUserStmt rn_stmt) ;
294 traceTc (text "tcs 1") ;
295 let { -- Make all the bound ids "global" ids, now that
296 -- they're notionally top-level bindings. This is
297 -- important: otherwise when we come to compile an expression
298 -- using these ids later, the byte code generator will consider
299 -- the occurrences to be free rather than global.
300 global_ids = map globaliseId bound_ids ;
301 globaliseId id = setGlobalIdDetails id VanillaGlobal ;
303 -- Update the interactive context
304 rn_env = ic_rn_local_env ictxt ;
305 type_env = ic_type_env ictxt ;
307 bound_names = map idName global_ids ;
308 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
310 -- Remove any shadowed bindings from the type_env;
311 -- they are inaccessible but might, I suppose, cause
312 -- a space leak if we leave them there
313 shadowed = [ n | name <- bound_names,
314 let rdr_name = mkRdrUnqual (nameOccName name),
315 Just n <- [lookupRdrEnv rn_env rdr_name] ] ;
317 filtered_type_env = delListFromNameEnv type_env shadowed ;
318 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
320 new_ic = ictxt { ic_rn_local_env = new_rn_env,
321 ic_type_env = new_type_env }
324 dumpOptTcRn Opt_D_dump_tc
325 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
326 text "Typechecked expr" <+> ppr tc_expr]) ;
328 returnM (new_ic, bound_names, tc_expr)
333 Here is the grand plan, implemented in tcUserStmt
335 What you type The IO [HValue] that hscStmt returns
336 ------------- ------------------------------------
337 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
340 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
343 expr (of IO type) ==> expr >>= \ v -> return [coerce HVal v]
344 [NB: result not printed] bindings: [it]
346 expr (of non-IO type, ==> let v = expr in print v >> return [coerce HVal v]
347 result showable) bindings: [it]
349 expr (of non-IO type,
350 result not showable) ==> error
354 ---------------------------
355 tcUserStmt :: RenamedStmt -> TcM ([Id], TypecheckedHsExpr)
356 tcUserStmt (ExprStmt expr _ loc)
357 = newUnique `thenM` \ uniq ->
359 fresh_it = itName uniq
360 the_bind = FunMonoBind fresh_it False
361 [ mkSimpleMatch [] expr placeHolderType loc ] loc
363 tryTcLIE_ (do { -- Try this if the other fails
364 traceTc (text "tcs 1b") ;
366 LetStmt (MonoBind the_bind [] NonRecursive),
367 ExprStmt (HsApp (HsVar printName) (HsVar fresh_it))
368 placeHolderType loc] })
369 (do { -- Try this first
370 traceTc (text "tcs 1a") ;
371 tc_stmts [BindStmt (VarPat fresh_it) expr loc] })
373 tcUserStmt stmt = tc_stmts [stmt]
375 ---------------------------
377 = do { io_ids <- mappM tcLookupId
378 [returnIOName, failIOName, bindIOName, thenIOName] ;
379 ioTyCon <- tcLookupTyCon ioTyConName ;
380 res_ty <- newTyVarTy liftedTypeKind ;
382 names = collectStmtsBinders stmts ;
383 return_id = head io_ids ; -- Rather gruesome
385 io_ty = (\ ty -> mkTyConApp ioTyCon [ty], res_ty) ;
387 -- mk_return builds the expression
388 -- returnIO @ [()] [coerce () x, .., coerce () z]
389 mk_return ids = HsApp (TyApp (HsVar return_id) [mkListTy unitTy])
390 (ExplicitList unitTy (map mk_item ids)) ;
392 mk_item id = HsApp (TyApp (HsVar unsafeCoerceId) [idType id, unitTy])
395 -- OK, we're ready to typecheck the stmts
396 traceTc (text "tcs 2") ;
397 ((ids, tc_stmts), lie) <-
398 getLIE $ tcStmtsAndThen combine DoExpr io_ty stmts $
400 -- Look up the names right in the middle,
401 -- where they will all be in scope
402 ids <- mappM tcLookupId names ;
403 return (ids, [ResultStmt (mk_return ids) noSrcLoc])
406 -- Simplify the context right here, so that we fail
407 -- if there aren't enough instances. Notably, when we see
409 -- we use recoverTc_ to try it <- e
410 -- and then let it = e
411 -- It's the simplify step that rejects the first.
412 traceTc (text "tcs 3") ;
413 const_binds <- tcSimplifyTop lie ;
415 -- Build result expression and zonk it
416 let { expr = mkHsLet const_binds $
417 HsDo DoExpr tc_stmts io_ids
418 (mkTyConApp ioTyCon [mkListTy unitTy]) noSrcLoc } ;
419 zonked_expr <- zonkTopExpr expr ;
420 zonked_ids <- zonkTopBndrs ids ;
422 return (zonked_ids, zonked_expr)
425 combine stmt (ids, stmts) = (ids, stmt:stmts)
429 tcRnExpr just finds the type of an expression
432 tcRnExpr :: HscEnv -> PersistentCompilerState
433 -> InteractiveContext
435 -> IO (PersistentCompilerState, Maybe Type)
436 tcRnExpr hsc_env pcs ictxt rdr_expr
437 = initTc hsc_env pcs iNTERACTIVE $
438 setInteractiveContext ictxt $ do {
440 (rn_expr, fvs) <- initRnInteractive ictxt (rnExpr rdr_expr) ;
443 -- Suck in the supporting declarations and typecheck them
444 tcg_env <- importSupportingDecls (fvs `plusFV` ubiquitousNames) ;
445 setGblEnv tcg_env $ do {
447 -- Now typecheck the expression;
448 -- it might have a rank-2 type (e.g. :t runST)
449 -- Hence the hole type (c.f. TcExpr.tcExpr_id)
450 ((tc_expr, res_ty), lie) <- getLIE (tcExpr_id rn_expr) ;
451 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
452 tcSimplifyTop lie_top ;
454 let { all_expr_ty = mkForAllTys qtvs $
455 mkFunTys (map idType dict_ids) $
457 zonkTcType all_expr_ty
460 smpl_doc = ptext SLIT("main expression")
465 tcRnThing :: HscEnv -> PersistentCompilerState
466 -> InteractiveContext
468 -> IO (PersistentCompilerState, Maybe [TyThing])
469 -- Look up a RdrName and return all the TyThings it might be
470 -- We treat a capitalised RdrName as both a data constructor
471 -- and as a type or class constructor; hence we return up to two results
472 tcRnThing hsc_env pcs ictxt rdr_name
473 = initTc hsc_env pcs iNTERACTIVE $
474 setInteractiveContext ictxt $ do {
476 -- If the identifier is a constructor (begins with an
477 -- upper-case letter), then we need to consider both
478 -- constructor and type class identifiers.
479 let { rdr_names = dataTcOccs rdr_name } ;
481 (msgs_s, mb_names) <- initRnInteractive ictxt
482 (mapAndUnzipM (tryTc . lookupOccRn) rdr_names) ;
483 let { names = catMaybes mb_names } ;
486 do { addMessages (head msgs_s) ; failM }
489 mapM_ addMessages msgs_s ; -- Add deprecation warnings
490 mapM tcLookupGlobal names -- and lookup up the entities
496 setInteractiveContext :: InteractiveContext -> TcRn m a -> TcRn m a
497 setInteractiveContext icxt thing_inside
498 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
499 updGblEnv (\ env -> env { tcg_rdr_env = ic_rn_gbl_env icxt,
500 tcg_type_env = ic_type_env icxt })
503 initRnInteractive :: InteractiveContext -> RnM a -> TcM a
504 -- Set the local RdrEnv from the interactive context
505 initRnInteractive ictxt rn_thing
506 = initRn CmdLineMode $
507 setLocalRdrEnv (ic_rn_local_env ictxt) $
511 %************************************************************************
513 Type-checking external-core modules
515 %************************************************************************
518 tcRnExtCore :: HscEnv -> PersistentCompilerState
520 -> IO (PersistentCompilerState, Maybe ModGuts)
521 -- Nothing => some error occurred
523 tcRnExtCore hsc_env pcs
524 (HsModule this_mod _ _ _ local_decls _ loc)
525 -- Rename the (Core) module. It's a bit like an interface
526 -- file: all names are original names
527 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
529 initTc hsc_env pcs this_mod $ addSrcLoc loc $ do {
531 -- Rename the source, only in interface mode.
532 -- rnSrcDecls handles fixity decls etc too, which won't occur
533 -- but that doesn't matter
534 let { local_group = mkGroup local_decls } ;
535 (_, rn_local_decls, fvs) <- initRn (InterfaceMode this_mod)
536 (rnSrcDecls local_group) ;
539 -- Get the supporting decls, and typecheck them all together
540 -- so that any mutually recursive types are done right
541 extra_decls <- slurpImpDecls fvs ;
542 tcg_env <- typecheckIfaceDecls (rn_local_decls `addImpDecls` extra_decls) ;
543 setGblEnv tcg_env $ do {
545 -- Now the core bindings
546 core_prs <- tcCoreBinds (hs_coreds rn_local_decls) ;
547 tcExtendGlobalValEnv (map fst core_prs) $ do {
551 bndrs = map fst core_prs ;
552 my_exports = map (Avail . idName) bndrs ;
553 -- ToDo: export the data types also?
555 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
557 mod_guts = ModGuts { mg_module = this_mod,
558 mg_usages = [], -- ToDo: compute usage
559 mg_dir_imps = [], -- ??
560 mg_exports = my_exports,
561 mg_types = final_type_env,
562 mg_insts = tcg_insts tcg_env,
563 mg_rules = hsCoreRules (tcg_rules tcg_env),
564 mg_binds = [Rec core_prs],
567 mg_rdr_env = emptyGlobalRdrEnv,
568 mg_fix_env = emptyFixityEnv,
569 mg_deprecs = NoDeprecs,
573 tcCoreDump mod_guts ;
580 %************************************************************************
582 Type-checking the top level of a module
584 %************************************************************************
587 tcRnSrcDecls :: [RdrNameHsDecl] -> TcM (TcGblEnv, FreeVars)
588 -- Returns the variables free in the decls
589 -- Reason: solely to report unused imports and bindings
590 tcRnSrcDecls [] = do { tcg_env <- getGblEnv ; return (tcg_env, emptyFVs) }
592 = do { let { (first_group, group_tail) = findSplice ds } ;
594 -- Type check the decls up to, but not including, the first splice
595 (tcg_env, src_fvs1) <- tcRnGroup first_group ;
597 -- If there is no splice, we're done
599 Nothing -> return (tcg_env, src_fvs1)
600 Just (SpliceDecl splice_expr splice_loc, rest_ds) -> do {
602 setGblEnv tcg_env $ do {
605 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
607 -- Rename the splice expression, and get its supporting decls
608 (rn_splice_expr, fvs) <- initRn SourceMode $
609 addSrcLoc splice_loc $
611 tcg_env <- importSupportingDecls fvs ;
612 setGblEnv tcg_env $ do {
614 -- Execute the splice
615 spliced_decls <- tcSpliceDecls rn_splice_expr ;
617 -- Glue them on the front of the remaining decls and loop
618 (tcg_env, src_fvs2) <- tcRnSrcDecls (spliced_decls ++ rest_ds) ;
620 return (tcg_env, src_fvs1 `plusFV` src_fvs2)
627 %************************************************************************
629 Type-checking the top level of a module
631 %************************************************************************
633 tcRnGroup takes a bunch of top-level source-code declarations, and
635 * gets supporting declarations from interface files
638 * and augments the TcGblEnv with the results
640 In Template Haskell it may be called repeatedly for each group of
641 declarations. It expects there to be an incoming TcGblEnv in the
642 monad; it augments it and returns the new TcGblEnv.
645 tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, FreeVars)
646 -- Returns the variables free in the decls
648 = do { -- Rename the declarations
649 (tcg_env, rn_decls, src_fvs) <- rnTopSrcDecls decls ;
650 setGblEnv tcg_env $ do {
652 -- Typecheck the declarations
653 tcg_env <- tcTopSrcDecls rn_decls ;
654 return (tcg_env, src_fvs)
657 ------------------------------------------------
658 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name, FreeVars)
660 = do { -- Bring top level binders into scope
661 (rdr_env, imports) <- importsFromLocalDecls group ;
662 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv`
664 tcg_imports = imports `plusImportAvails`
668 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
670 -- Rename the source decls
671 (tcg_env, rn_src_decls, src_fvs) <- initRn SourceMode (rnSrcDecls group) ;
672 setGblEnv tcg_env $ do {
676 -- Import consquential imports
677 rn_imp_decls <- slurpImpDecls (src_fvs `plusFV` implicitModuleFVs src_fvs) ;
678 let { rn_decls = rn_src_decls `addImpDecls` rn_imp_decls } ;
680 -- Dump trace of renaming part
681 rnDump (ppr rn_decls) ;
682 rnStats rn_imp_decls ;
684 return (tcg_env, rn_decls, src_fvs)
687 ------------------------------------------------
688 tcTopSrcDecls :: HsGroup Name -> TcM TcGblEnv
689 tcTopSrcDecls rn_decls
690 = fixM (\ unf_env -> do {
691 -- Loop back the final environment, including the fully zonked
692 -- versions of bindings from this module. In the presence of mutual
693 -- recursion, interface type signatures may mention variables defined
694 -- in this module, which is why the knot is so big
697 ((tcg_env, binds, rules, fords), lie) <- getLIE (
698 tc_src_decls unf_env rn_decls
701 -- tcSimplifyTop deals with constant or ambiguous InstIds.
702 -- How could there be ambiguous ones? They can only arise if a
703 -- top-level decl falls under the monomorphism
704 -- restriction, and no subsequent decl instantiates its
705 -- type. (Usually, ambiguous type variables are resolved
706 -- during the generalisation step.)
707 traceTc (text "Tc8") ;
708 inst_binds <- setGblEnv tcg_env (tcSimplifyTop lie) ;
709 -- The setGblEnv exposes the instances to tcSimplifyTop
711 -- Backsubstitution. This must be done last.
712 -- Even tcSimplifyTop may do some unification.
713 traceTc (text "Tc9") ;
714 (ids, binds', fords', rules') <- zonkTopDecls (binds `andMonoBinds` inst_binds)
717 let { tcg_env' = tcg_env { tcg_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) ids,
718 tcg_binds = tcg_binds tcg_env `andMonoBinds` binds',
719 tcg_rules = tcg_rules tcg_env ++ rules',
720 tcg_fords = tcg_fords tcg_env ++ fords' } } ;
726 (HsGroup { hs_tyclds = tycl_decls,
727 hs_instds = inst_decls,
728 hs_fords = foreign_decls,
729 hs_defds = default_decls,
730 hs_ruleds = rule_decls,
731 hs_valds = val_binds })
732 = do { -- Type-check the type and class decls, and all imported decls
733 traceTc (text "Tc2") ;
734 tcg_env <- tcTyClDecls unf_env tycl_decls ;
735 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, fvs) <- tcInstDecls1 tycl_decls inst_decls ;
741 setGblEnv tcg_env $ do {
742 tcg_env <- importSupportingDecls fvs ;
743 setGblEnv tcg_env $ do {
745 -- Foreign import declarations next. No zonking necessary
746 -- here; we can tuck them straight into the global environment.
747 traceTc (text "Tc4") ;
748 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
749 tcExtendGlobalValEnv fi_ids $
750 updGblEnv (\gbl -> gbl { tcg_fords = tcg_fords gbl ++ fi_decls })
753 -- Default declarations
754 traceTc (text "Tc4a") ;
755 default_tys <- tcDefaults default_decls ;
756 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
758 -- Value declarations next
759 -- We also typecheck any extra binds that came out
760 -- of the "deriving" process
761 traceTc (text "Tc5") ;
762 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds `ThenBinds` deriv_binds) ;
763 setLclTypeEnv lcl_env $ do {
765 -- Second pass over class and instance declarations,
766 -- plus rules and foreign exports, to generate bindings
767 traceTc (text "Tc6") ;
768 (cls_dm_binds, dm_ids) <- tcClassDecls2 tycl_decls ;
769 tcExtendGlobalValEnv dm_ids $ do {
770 inst_binds <- tcInstDecls2 inst_infos ;
771 showLIE "after instDecls2" ;
774 -- They need to be zonked, so we return them
775 traceTc (text "Tc7") ;
776 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
779 -- Need to partition them because the source rules
780 -- must be zonked before adding them to tcg_rules
781 -- NB: built-in rules come in as IfaceRuleOut's, and
782 -- get added to tcg_rules right here by tcExtendRules
783 rules <- tcRules rule_decls ;
784 let { (src_rules, iface_rules) = partition isSrcRule rules } ;
785 tcExtendRules iface_rules $ do {
788 tcg_env <- getGblEnv ;
789 let { all_binds = tc_val_binds `AndMonoBinds`
790 inst_binds `AndMonoBinds`
791 cls_dm_binds `AndMonoBinds`
794 return (tcg_env, all_binds, src_rules, foe_decls)
799 tcTyClDecls :: RecTcGblEnv
803 -- tcTyClDecls deals with
804 -- type and class decls (some source, some imported)
805 -- interface signatures (checked lazily)
807 -- It returns the TcGblEnv for this module, and side-effects the
808 -- persistent compiler state to reflect the things imported from
811 tcTyClDecls unf_env tycl_decls
812 -- (unf_env :: RecTcGblEnv) is used for type-checking interface pragmas
813 -- which is done lazily [ie failure just drops the pragma
814 -- without having any global-failure effect].
817 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
818 -- an error we'd better stop now, to avoid a cascade
820 traceTc (text "TyCl1") `thenM_`
821 tcTyAndClassDecls tycl_decls `thenM` \ tycl_things ->
822 tcExtendGlobalEnv tycl_things $
824 -- Interface type signatures
825 -- We tie a knot so that the Ids read out of interfaces are in scope
826 -- when we read their pragmas.
827 -- What we rely on is that pragmas are typechecked lazily; if
828 -- any type errors are found (ie there's an inconsistency)
829 -- we silently discard the pragma
830 traceTc (text "TyCl2") `thenM_`
831 tcInterfaceSigs unf_env tycl_decls `thenM` \ sig_ids ->
832 tcExtendGlobalValEnv sig_ids $
834 getGblEnv -- Return the TcLocals environment
839 %************************************************************************
841 Load the old interface file for this module (unless
842 we have it aleady), and check whether it is up to date
845 %************************************************************************
848 checkOldIface :: HscEnv
849 -> PersistentCompilerState
851 -> FilePath -- Where the interface file is
852 -> Bool -- Source unchanged
853 -> Maybe ModIface -- Old interface from compilation manager, if any
854 -> IO (PersistentCompilerState, Maybe (RecompileRequired, Maybe ModIface))
855 -- Nothing <=> errors happened
857 checkOldIface hsc_env pcs mod iface_path source_unchanged maybe_iface
858 = do { showPass (hsc_dflags hsc_env)
859 ("Checking old interface for " ++ moduleUserString mod) ;
861 initTc hsc_env pcs mod
862 (check_old_iface iface_path source_unchanged maybe_iface)
865 check_old_iface iface_path source_unchanged maybe_iface
866 = -- CHECK WHETHER THE SOURCE HAS CHANGED
867 ifM (not source_unchanged)
868 (traceHiDiffs (nest 4 (text "Source file changed or recompilation check turned off")))
871 -- If the source has changed and we're in interactive mode, avoid reading
872 -- an interface; just return the one we might have been supplied with.
873 getGhciMode `thenM` \ ghci_mode ->
874 if (ghci_mode == Interactive) && not source_unchanged then
875 returnM (outOfDate, maybe_iface)
879 Just old_iface -> -- Use the one we already have
880 checkVersions source_unchanged old_iface `thenM` \ recomp ->
881 returnM (recomp, Just old_iface)
883 Nothing -- Try and read it from a file
884 -> getModule `thenM` \ this_mod ->
885 readIface this_mod iface_path False `thenM` \ read_result ->
887 Left err -> -- Old interface file not found, or garbled; give up
889 text "Cannot read old interface file:"
890 $$ nest 4 (text (showException err))) `thenM_`
891 returnM (outOfDate, Nothing)
893 Right parsed_iface ->
894 initRn (InterfaceMode this_mod)
895 (loadOldIface parsed_iface) `thenM` \ m_iface ->
896 checkVersions source_unchanged m_iface `thenM` \ recomp ->
897 returnM (recomp, Just m_iface)
901 %************************************************************************
903 Type-check and rename supporting declarations
904 This is used to deal with the free vars of a splice,
905 or derived code: slurp in the necessary declarations,
906 typecheck them, and add them to the EPS
908 %************************************************************************
911 importSupportingDecls :: FreeVars -> TcM TcGblEnv
912 -- Completely deal with the supporting imports needed
913 -- by the specified free-var set
914 importSupportingDecls fvs
915 = do { traceRn (text "Import supporting decls for" <+> ppr (nameSetToList fvs)) ;
916 decls <- slurpImpDecls fvs ;
917 traceRn (text "...namely:" <+> vcat (map ppr decls)) ;
918 typecheckIfaceDecls (mkGroup decls) }
920 typecheckIfaceDecls :: HsGroup Name -> TcM TcGblEnv
921 -- The decls are all interface-file declarations
922 -- Usually they are all from other modules, but when we are reading
923 -- this module's interface from a file, it's possible that some of
924 -- them are for the module being compiled.
925 -- That is why the tcExtendX functions need to do partitioning.
927 -- If all the decls are from other modules, the returned TcGblEnv
928 -- will have an empty tc_genv, but its tc_inst_env and tc_ist
929 -- caches may have been augmented.
930 typecheckIfaceDecls (HsGroup { hs_tyclds = tycl_decls,
931 hs_instds = inst_decls,
932 hs_ruleds = rule_decls })
933 = do { -- Typecheck the type, class, and interface-sig decls
934 tcg_env <- fixM (\ unf_env -> tcTyClDecls unf_env tycl_decls) ;
935 setGblEnv tcg_env $ do {
937 -- Typecheck the instance decls, and rules
938 -- Note that imported dictionary functions are already
939 -- in scope from the preceding tcTyClDecls
940 tcIfaceInstDecls inst_decls `thenM` \ dfuns ->
941 tcExtendInstEnv dfuns $
942 tcRules rule_decls `thenM` \ rules ->
943 tcExtendRules rules $
945 getGblEnv -- Return the environment
951 %*********************************************************
953 mkGlobalContext: make up an interactive context
955 Used for initialising the lexical environment
956 of the interactive read-eval-print loop
958 %*********************************************************
963 :: HscEnv -> PersistentCompilerState
964 -> [Module] -- Expose these modules' top-level scope
965 -> [Module] -- Expose these modules' exports only
966 -> IO (PersistentCompilerState, Maybe GlobalRdrEnv)
968 mkGlobalContext hsc_env pcs toplevs exports
969 = initTc hsc_env pcs iNTERACTIVE $ do {
971 toplev_envs <- mappM getTopLevScope toplevs ;
972 export_envs <- mappM getModuleExports exports ;
973 returnM (foldr plusGlobalRdrEnv emptyGlobalRdrEnv
974 (toplev_envs ++ export_envs))
977 getTopLevScope :: Module -> TcRn m GlobalRdrEnv
979 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
980 case mi_globals iface of
981 Nothing -> panic "getTopLevScope"
982 Just env -> returnM env }
984 getModuleExports :: Module -> TcRn m GlobalRdrEnv
986 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
987 returnM (foldl add emptyGlobalRdrEnv (mi_exports iface)) }
989 prov_fn n = NonLocalDef ImplicitImport
991 = plusGlobalRdrEnv env (mkGlobalRdrEnv mod True prov_fn avails NoDeprecs)
993 contextDoc = text "context for compiling statements"
999 -> PersistentCompilerState -- IN: persistent compiler state
1000 -> Module -- module to inspect
1001 -> Bool -- grab just the exports, or the whole toplev
1002 -> IO (PersistentCompilerState, Maybe [TyThing])
1004 getModuleContents hsc_env pcs mod exports_only
1005 = initTc hsc_env pcs iNTERACTIVE $ do {
1007 -- Load the interface if necessary (a home module will certainly
1008 -- alraedy be loaded, but a package module might not be)
1009 iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
1011 let { export_names = availsToNameSet export_avails ;
1012 export_avails = [ avail | (mn, avails) <- mi_exports iface,
1013 avail <- avails ] } ;
1015 all_names <- if exports_only then
1017 else case mi_globals iface of {
1019 return (get_locals rdr_env) ;
1021 Nothing -> do { addErr (noRdrEnvErr mod) ;
1022 return export_names } } ;
1023 -- Invariant; we only have (not exports_only)
1024 -- for a home module so it must already be in the HIT
1025 -- So the Nothing case is a bug
1027 env <- importSupportingDecls all_names ;
1028 setGblEnv env (mappM tcLookupGlobal (nameSetToList all_names))
1031 -- Grab all the things from the global env that are locally def'd
1032 get_locals rdr_env = mkNameSet [ gre_name gre
1033 | elts <- rdrEnvElts rdr_env,
1036 -- Make a set because a name is often in the envt in
1037 -- both qualified and unqualified forms
1039 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1040 <+> quotes (ppr mod)
1044 %************************************************************************
1048 %************************************************************************
1052 = do { ghci_mode <- getGhciMode ;
1053 tcg_env <- getGblEnv ;
1054 check_main ghci_mode tcg_env
1057 check_main ghci_mode tcg_env
1058 -- If we are in module Main, check that 'main' is defined.
1059 -- It may be imported from another module, in which case
1060 -- we have to drag in its.
1062 -- Also form the definition
1063 -- $main = runIO main
1064 -- so we need to slurp in runIO too.
1066 -- ToDo: We have to return the main_name separately, because it's a
1067 -- bona fide 'use', and should be recorded as such, but the others
1070 -- Blimey: a whole page of code to do this...
1072 | mod_name /= mAIN_Name
1073 = return (tcg_env, emptyFVs)
1075 | not (main_RDR_Unqual `elemRdrEnv` rdr_env)
1076 = do { complain_no_main; return (tcg_env, emptyFVs) }
1079 = do { -- Check that 'main' is in scope
1080 -- It might be imported from another module!
1081 main_name <- lookupSrcName main_RDR_Unqual ;
1084 tcg_env <- importSupportingDecls (unitFV runIOName) ;
1085 setGblEnv tcg_env $ do {
1087 -- $main :: IO () = runIO main
1088 let { rhs = HsApp (HsVar runIOName) (HsVar main_name) } ;
1090 (main_bind, top_lie) <- getLIE (
1091 addSrcLoc (getSrcLoc main_name) $
1092 addErrCtxt mainCtxt $ do {
1093 (main_expr, ty) <- tcExpr_id rhs ;
1094 let { dollar_main_id = setIdLocalExported (mkLocalId dollarMainName ty) } ;
1095 return (VarMonoBind dollar_main_id main_expr)
1098 inst_binds <- tcSimplifyTop top_lie ;
1100 (ids, binds') <- zonkTopBinds (main_bind `andMonoBinds` inst_binds) ;
1102 let { tcg_env' = tcg_env {
1103 tcg_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) ids,
1104 tcg_binds = tcg_binds tcg_env `andMonoBinds` binds' } } ;
1106 return (tcg_env', unitFV main_name)
1109 mod_name = moduleName (tcg_mod tcg_env)
1110 rdr_env = tcg_rdr_env tcg_env
1112 main_RDR_Unqual :: RdrName
1113 main_RDR_Unqual = mkUnqual varName FSLIT("main")
1114 -- Don't get a RdrName from PrelNames.mainName, because
1115 -- nameRdrNamegets an Orig RdrName, and we want a Qual or Unqual one.
1116 -- An Unqual one will do just fine
1118 complain_no_main | ghci_mode == Interactive = return ()
1119 | otherwise = addErr noMainMsg
1120 -- In interactive mode, don't worry about the absence of 'main'
1122 mainCtxt = ptext SLIT("When checking the type of 'main'")
1123 noMainMsg = ptext SLIT("No 'main' defined in module Main")
1127 %************************************************************************
1131 %************************************************************************
1134 rnDump :: SDoc -> TcRn m ()
1135 -- Dump, with a banner, if -ddump-rn
1136 rnDump doc = dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc)
1138 tcDump :: TcGblEnv -> TcRn m ()
1140 = do { dflags <- getDOpts ;
1142 -- Dump short output if -ddump-types or -ddump-tc
1143 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1144 (dumpTcRn short_dump) ;
1146 -- Dump bindings if -ddump-tc
1147 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1150 short_dump = pprTcGblEnv env
1151 full_dump = ppr (tcg_binds env)
1152 -- NB: foreign x-d's have undefined's in their types;
1153 -- hence can't show the tc_fords
1156 = do { dflags <- getDOpts ;
1157 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1158 (dumpTcRn (pprModGuts mod_guts)) ;
1160 -- Dump bindings if -ddump-tc
1161 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1163 full_dump = pprCoreBindings (mg_binds mod_guts)
1165 -- It's unpleasant having both pprModGuts and pprModDetails here
1166 pprTcGblEnv :: TcGblEnv -> SDoc
1167 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1168 tcg_insts = dfun_ids,
1169 tcg_rules = rules })
1170 = vcat [ ppr_types dfun_ids type_env
1171 , ppr_insts dfun_ids
1172 , vcat (map ppr rules)
1173 , ppr_gen_tycons (typeEnvTyCons type_env)]
1175 pprModGuts :: ModGuts -> SDoc
1176 pprModGuts (ModGuts { mg_types = type_env,
1178 = vcat [ ppr_types [] type_env,
1182 ppr_types :: [Var] -> TypeEnv -> SDoc
1183 ppr_types dfun_ids type_env
1184 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1186 ids = [id | id <- typeEnvIds type_env, want_sig id]
1187 want_sig id | opt_PprStyle_Debug = True
1188 | otherwise = isLocalId id &&
1189 isExternalName (idName id) &&
1190 not (id `elem` dfun_ids)
1191 -- isLocalId ignores data constructors, records selectors etc.
1192 -- The isExternalName ignores local dictionary and method bindings
1193 -- that the type checker has invented. Top-level user-defined things
1194 -- have External names.
1196 ppr_insts :: [Var] -> SDoc
1197 ppr_insts [] = empty
1198 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1200 ppr_sigs :: [Var] -> SDoc
1202 -- Print type signatures
1203 -- Convert to HsType so that we get source-language style printing
1204 -- And sort by RdrName
1205 = vcat $ map ppr_sig $ sortLt lt_sig $
1206 [ (getRdrName id, toHsType (idType id))
1209 lt_sig (n1,_) (n2,_) = n1 < n2
1210 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
1213 ppr_rules :: [IdCoreRule] -> SDoc
1214 ppr_rules [] = empty
1215 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1216 nest 4 (pprIdRules rs),
1219 ppr_gen_tycons [] = empty
1220 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
1221 vcat (map ppr_gen_tycon tcs),
1225 -- x&y are now Id's, not CoreExpr's
1227 | Just ep <- tyConGenInfo tycon
1228 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
1230 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
1233 = vcat [ ptext SLIT("Rep type:") <+> ppr (tcFunResultTy from_tau),
1234 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
1235 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
1238 (_,from_tau) = tcSplitForAllTys (idType from)