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(..),
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 (splice_expr, 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 (rnExpr splice_expr) ;
609 tcg_env <- importSupportingDecls fvs ;
610 setGblEnv tcg_env $ do {
612 -- Execute the splice
613 spliced_decls <- tcSpliceDecls rn_splice_expr ;
615 -- Glue them on the front of the remaining decls and loop
616 (tcg_env, src_fvs2) <- tcRnSrcDecls (spliced_decls ++ rest_ds) ;
618 return (tcg_env, src_fvs1 `plusFV` src_fvs2)
625 %************************************************************************
627 Type-checking the top level of a module
629 %************************************************************************
631 tcRnGroup takes a bunch of top-level source-code declarations, and
633 * gets supporting declarations from interface files
636 * and augments the TcGblEnv with the results
638 In Template Haskell it may be called repeatedly for each group of
639 declarations. It expects there to be an incoming TcGblEnv in the
640 monad; it augments it and returns the new TcGblEnv.
643 tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, FreeVars)
644 -- Returns the variables free in the decls
646 = do { -- Rename the declarations
647 (tcg_env, rn_decls, src_fvs) <- rnTopSrcDecls decls ;
648 setGblEnv tcg_env $ do {
650 -- Typecheck the declarations
651 tcg_env <- tcTopSrcDecls rn_decls ;
652 return (tcg_env, src_fvs)
655 ------------------------------------------------
656 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name, FreeVars)
658 = do { -- Bring top level binders into scope
659 (rdr_env, imports) <- importsFromLocalDecls group ;
660 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv`
662 tcg_imports = imports `plusImportAvails`
666 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
668 -- Rename the source decls
669 (tcg_env, rn_src_decls, src_fvs) <- initRn SourceMode (rnSrcDecls group) ;
670 setGblEnv tcg_env $ do {
674 -- Import consquential imports
675 rn_imp_decls <- slurpImpDecls (src_fvs `plusFV` implicitModuleFVs src_fvs) ;
676 let { rn_decls = rn_src_decls `addImpDecls` rn_imp_decls } ;
678 -- Dump trace of renaming part
679 rnDump (ppr rn_decls) ;
680 rnStats rn_imp_decls ;
682 return (tcg_env, rn_decls, src_fvs)
685 ------------------------------------------------
686 tcTopSrcDecls :: HsGroup Name -> TcM TcGblEnv
687 tcTopSrcDecls rn_decls
688 = fixM (\ unf_env -> do {
689 -- Loop back the final environment, including the fully zonked
690 -- versions of bindings from this module. In the presence of mutual
691 -- recursion, interface type signatures may mention variables defined
692 -- in this module, which is why the knot is so big
695 ((tcg_env, binds, rules, fords), lie) <- getLIE (
696 tc_src_decls unf_env rn_decls
699 -- tcSimplifyTop deals with constant or ambiguous InstIds.
700 -- How could there be ambiguous ones? They can only arise if a
701 -- top-level decl falls under the monomorphism
702 -- restriction, and no subsequent decl instantiates its
703 -- type. (Usually, ambiguous type variables are resolved
704 -- during the generalisation step.)
705 traceTc (text "Tc8") ;
706 inst_binds <- setGblEnv tcg_env (tcSimplifyTop lie) ;
707 -- The setGblEnv exposes the instances to tcSimplifyTop
709 -- Backsubstitution. This must be done last.
710 -- Even tcSimplifyTop may do some unification.
711 traceTc (text "Tc9") ;
712 (ids, binds', fords', rules') <- zonkTopDecls (binds `andMonoBinds` inst_binds)
715 let { tcg_env' = tcg_env { tcg_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) ids,
716 tcg_binds = tcg_binds tcg_env `andMonoBinds` binds',
717 tcg_rules = tcg_rules tcg_env ++ rules',
718 tcg_fords = tcg_fords tcg_env ++ fords' } } ;
724 (HsGroup { hs_tyclds = tycl_decls,
725 hs_instds = inst_decls,
726 hs_fords = foreign_decls,
727 hs_defds = default_decls,
728 hs_ruleds = rule_decls,
729 hs_valds = val_binds })
730 = do { -- Type-check the type and class decls, and all imported decls
731 traceTc (text "Tc2") ;
732 tcg_env <- tcTyClDecls unf_env tycl_decls ;
733 setGblEnv tcg_env $ do {
735 -- Source-language instances, including derivings,
736 -- and import the supporting declarations
737 traceTc (text "Tc3") ;
738 (tcg_env, inst_infos, deriv_binds, fvs) <- tcInstDecls1 tycl_decls inst_decls ;
739 setGblEnv tcg_env $ do {
740 tcg_env <- importSupportingDecls fvs ;
741 setGblEnv tcg_env $ do {
743 -- Foreign import declarations next. No zonking necessary
744 -- here; we can tuck them straight into the global environment.
745 traceTc (text "Tc4") ;
746 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
747 tcExtendGlobalValEnv fi_ids $
748 updGblEnv (\gbl -> gbl { tcg_fords = tcg_fords gbl ++ fi_decls })
751 -- Default declarations
752 traceTc (text "Tc4a") ;
753 default_tys <- tcDefaults default_decls ;
754 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
756 -- Value declarations next
757 -- We also typecheck any extra binds that came out
758 -- of the "deriving" process
759 traceTc (text "Tc5") ;
760 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds `ThenBinds` deriv_binds) ;
761 setLclTypeEnv lcl_env $ do {
763 -- Second pass over class and instance declarations,
764 -- plus rules and foreign exports, to generate bindings
765 traceTc (text "Tc6") ;
766 (cls_dm_binds, dm_ids) <- tcClassDecls2 tycl_decls ;
767 tcExtendGlobalValEnv dm_ids $ do {
768 inst_binds <- tcInstDecls2 inst_infos ;
769 showLIE "after instDecls2" ;
772 -- They need to be zonked, so we return them
773 traceTc (text "Tc7") ;
774 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
777 -- Need to partition them because the source rules
778 -- must be zonked before adding them to tcg_rules
779 -- NB: built-in rules come in as IfaceRuleOut's, and
780 -- get added to tcg_rules right here by tcExtendRules
781 rules <- tcRules rule_decls ;
782 let { (src_rules, iface_rules) = partition isSrcRule rules } ;
783 tcExtendRules iface_rules $ do {
786 tcg_env <- getGblEnv ;
787 let { all_binds = tc_val_binds `AndMonoBinds`
788 inst_binds `AndMonoBinds`
789 cls_dm_binds `AndMonoBinds`
792 return (tcg_env, all_binds, src_rules, foe_decls)
797 tcTyClDecls :: RecTcGblEnv
801 -- tcTyClDecls deals with
802 -- type and class decls (some source, some imported)
803 -- interface signatures (checked lazily)
805 -- It returns the TcGblEnv for this module, and side-effects the
806 -- persistent compiler state to reflect the things imported from
809 tcTyClDecls unf_env tycl_decls
810 -- (unf_env :: RecTcGblEnv) is used for type-checking interface pragmas
811 -- which is done lazily [ie failure just drops the pragma
812 -- without having any global-failure effect].
815 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
816 -- an error we'd better stop now, to avoid a cascade
818 traceTc (text "TyCl1") `thenM_`
819 tcTyAndClassDecls tycl_decls `thenM` \ tycl_things ->
820 tcExtendGlobalEnv tycl_things $
822 -- Interface type signatures
823 -- We tie a knot so that the Ids read out of interfaces are in scope
824 -- when we read their pragmas.
825 -- What we rely on is that pragmas are typechecked lazily; if
826 -- any type errors are found (ie there's an inconsistency)
827 -- we silently discard the pragma
828 traceTc (text "TyCl2") `thenM_`
829 tcInterfaceSigs unf_env tycl_decls `thenM` \ sig_ids ->
830 tcExtendGlobalValEnv sig_ids $
832 getGblEnv -- Return the TcLocals environment
837 %************************************************************************
839 Load the old interface file for this module (unless
840 we have it aleady), and check whether it is up to date
843 %************************************************************************
846 checkOldIface :: HscEnv
847 -> PersistentCompilerState
849 -> FilePath -- Where the interface file is
850 -> Bool -- Source unchanged
851 -> Maybe ModIface -- Old interface from compilation manager, if any
852 -> IO (PersistentCompilerState, Maybe (RecompileRequired, Maybe ModIface))
853 -- Nothing <=> errors happened
855 checkOldIface hsc_env pcs mod iface_path source_unchanged maybe_iface
856 = do { showPass (hsc_dflags hsc_env)
857 ("Checking old interface for " ++ moduleUserString mod) ;
859 initTc hsc_env pcs mod
860 (check_old_iface iface_path source_unchanged maybe_iface)
863 check_old_iface iface_path source_unchanged maybe_iface
864 = -- CHECK WHETHER THE SOURCE HAS CHANGED
865 ifM (not source_unchanged)
866 (traceHiDiffs (nest 4 (text "Source file changed or recompilation check turned off")))
869 -- If the source has changed and we're in interactive mode, avoid reading
870 -- an interface; just return the one we might have been supplied with.
871 getGhciMode `thenM` \ ghci_mode ->
872 if (ghci_mode == Interactive) && not source_unchanged then
873 returnM (outOfDate, maybe_iface)
877 Just old_iface -> -- Use the one we already have
878 checkVersions source_unchanged old_iface `thenM` \ recomp ->
879 returnM (recomp, Just old_iface)
881 Nothing -- Try and read it from a file
882 -> getModule `thenM` \ this_mod ->
883 readIface this_mod iface_path False `thenM` \ read_result ->
885 Left err -> -- Old interface file not found, or garbled; give up
887 text "Cannot read old interface file:"
888 $$ nest 4 (text (showException err))) `thenM_`
889 returnM (outOfDate, Nothing)
891 Right parsed_iface ->
892 initRn (InterfaceMode this_mod)
893 (loadOldIface parsed_iface) `thenM` \ m_iface ->
894 checkVersions source_unchanged m_iface `thenM` \ recomp ->
895 returnM (recomp, Just m_iface)
899 %************************************************************************
901 Type-check and rename supporting declarations
902 This is used to deal with the free vars of a splice,
903 or derived code: slurp in the necessary declarations,
904 typecheck them, and add them to the EPS
906 %************************************************************************
909 importSupportingDecls :: FreeVars -> TcM TcGblEnv
910 -- Completely deal with the supporting imports needed
911 -- by the specified free-var set
912 importSupportingDecls fvs
913 = do { traceRn (text "Import supporting decls for" <+> ppr (nameSetToList fvs)) ;
914 decls <- slurpImpDecls fvs ;
915 traceRn (text "...namely:" <+> vcat (map ppr decls)) ;
916 typecheckIfaceDecls (mkGroup decls) }
918 typecheckIfaceDecls :: HsGroup Name -> TcM TcGblEnv
919 -- The decls are all interface-file declarations
920 -- Usually they are all from other modules, but when we are reading
921 -- this module's interface from a file, it's possible that some of
922 -- them are for the module being compiled.
923 -- That is why the tcExtendX functions need to do partitioning.
925 -- If all the decls are from other modules, the returned TcGblEnv
926 -- will have an empty tc_genv, but its tc_inst_env and tc_ist
927 -- caches may have been augmented.
928 typecheckIfaceDecls (HsGroup { hs_tyclds = tycl_decls,
929 hs_instds = inst_decls,
930 hs_ruleds = rule_decls })
931 = do { -- Typecheck the type, class, and interface-sig decls
932 tcg_env <- fixM (\ unf_env -> tcTyClDecls unf_env tycl_decls) ;
933 setGblEnv tcg_env $ do {
935 -- Typecheck the instance decls, and rules
936 -- Note that imported dictionary functions are already
937 -- in scope from the preceding tcTyClDecls
938 tcIfaceInstDecls inst_decls `thenM` \ dfuns ->
939 tcExtendInstEnv dfuns $
940 tcRules rule_decls `thenM` \ rules ->
941 tcExtendRules rules $
943 getGblEnv -- Return the environment
949 %*********************************************************
951 mkGlobalContext: make up an interactive context
953 Used for initialising the lexical environment
954 of the interactive read-eval-print loop
956 %*********************************************************
961 :: HscEnv -> PersistentCompilerState
962 -> [Module] -- Expose these modules' top-level scope
963 -> [Module] -- Expose these modules' exports only
964 -> IO (PersistentCompilerState, Maybe GlobalRdrEnv)
966 mkGlobalContext hsc_env pcs toplevs exports
967 = initTc hsc_env pcs iNTERACTIVE $ do {
969 toplev_envs <- mappM getTopLevScope toplevs ;
970 export_envs <- mappM getModuleExports exports ;
971 returnM (foldr plusGlobalRdrEnv emptyGlobalRdrEnv
972 (toplev_envs ++ export_envs))
975 getTopLevScope :: Module -> TcRn m GlobalRdrEnv
977 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
978 case mi_globals iface of
979 Nothing -> panic "getTopLevScope"
980 Just env -> returnM env }
982 getModuleExports :: Module -> TcRn m GlobalRdrEnv
984 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
985 returnM (foldl add emptyGlobalRdrEnv (mi_exports iface)) }
987 prov_fn n = NonLocalDef ImplicitImport
989 = plusGlobalRdrEnv env (mkGlobalRdrEnv mod True prov_fn avails NoDeprecs)
991 contextDoc = text "context for compiling statements"
997 -> PersistentCompilerState -- IN: persistent compiler state
998 -> Module -- module to inspect
999 -> Bool -- grab just the exports, or the whole toplev
1000 -> IO (PersistentCompilerState, Maybe [TyThing])
1002 getModuleContents hsc_env pcs mod exports_only
1003 = initTc hsc_env pcs iNTERACTIVE $ do {
1005 -- Load the interface if necessary (a home module will certainly
1006 -- alraedy be loaded, but a package module might not be)
1007 iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
1009 let { export_names = availsToNameSet export_avails ;
1010 export_avails = [ avail | (mn, avails) <- mi_exports iface,
1011 avail <- avails ] } ;
1013 all_names <- if exports_only then
1015 else case mi_globals iface of {
1017 return (get_locals rdr_env) ;
1019 Nothing -> do { addErr (noRdrEnvErr mod) ;
1020 return export_names } } ;
1021 -- Invariant; we only have (not exports_only)
1022 -- for a home module so it must already be in the HIT
1023 -- So the Nothing case is a bug
1025 env <- importSupportingDecls all_names ;
1026 setGblEnv env (mappM tcLookupGlobal (nameSetToList all_names))
1029 -- Grab all the things from the global env that are locally def'd
1030 get_locals rdr_env = mkNameSet [ gre_name gre
1031 | elts <- rdrEnvElts rdr_env,
1034 -- Make a set because a name is often in the envt in
1035 -- both qualified and unqualified forms
1037 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1038 <+> quotes (ppr mod)
1042 %************************************************************************
1046 %************************************************************************
1050 = do { ghci_mode <- getGhciMode ;
1051 tcg_env <- getGblEnv ;
1052 check_main ghci_mode tcg_env
1055 check_main ghci_mode tcg_env
1056 -- If we are in module Main, check that 'main' is defined.
1057 -- It may be imported from another module, in which case
1058 -- we have to drag in its.
1060 -- Also form the definition
1061 -- $main = runIO main
1062 -- so we need to slurp in runIO too.
1064 -- ToDo: We have to return the main_name separately, because it's a
1065 -- bona fide 'use', and should be recorded as such, but the others
1068 -- Blimey: a whole page of code to do this...
1070 | mod_name /= mAIN_Name
1071 = return (tcg_env, emptyFVs)
1073 | not (main_RDR_Unqual `elemRdrEnv` rdr_env)
1074 = do { complain_no_main; return (tcg_env, emptyFVs) }
1077 = do { -- Check that 'main' is in scope
1078 -- It might be imported from another module!
1079 main_name <- lookupSrcName main_RDR_Unqual ;
1082 tcg_env <- importSupportingDecls (unitFV runIOName) ;
1083 setGblEnv tcg_env $ do {
1085 -- $main :: IO () = runIO main
1086 let { rhs = HsApp (HsVar runIOName) (HsVar main_name) } ;
1088 (main_bind, top_lie) <- getLIE (
1089 addSrcLoc (getSrcLoc main_name) $
1090 addErrCtxt mainCtxt $ do {
1091 (main_expr, ty) <- tcExpr_id rhs ;
1092 let { dollar_main_id = setIdLocalExported (mkLocalId dollarMainName ty) } ;
1093 return (VarMonoBind dollar_main_id main_expr)
1096 inst_binds <- tcSimplifyTop top_lie ;
1098 (ids, binds') <- zonkTopBinds (main_bind `andMonoBinds` inst_binds) ;
1100 let { tcg_env' = tcg_env {
1101 tcg_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) ids,
1102 tcg_binds = tcg_binds tcg_env `andMonoBinds` binds' } } ;
1104 return (tcg_env', unitFV main_name)
1107 mod_name = moduleName (tcg_mod tcg_env)
1108 rdr_env = tcg_rdr_env tcg_env
1110 main_RDR_Unqual :: RdrName
1111 main_RDR_Unqual = mkUnqual varName FSLIT("main")
1112 -- Don't get a RdrName from PrelNames.mainName, because
1113 -- nameRdrNamegets an Orig RdrName, and we want a Qual or Unqual one.
1114 -- An Unqual one will do just fine
1116 complain_no_main | ghci_mode == Interactive = return ()
1117 | otherwise = addErr noMainMsg
1118 -- In interactive mode, don't worry about the absence of 'main'
1120 mainCtxt = ptext SLIT("When checking the type of 'main'")
1121 noMainMsg = ptext SLIT("No 'main' defined in module Main")
1125 %************************************************************************
1129 %************************************************************************
1132 rnDump :: SDoc -> TcRn m ()
1133 -- Dump, with a banner, if -ddump-rn
1134 rnDump doc = dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc)
1136 tcDump :: TcGblEnv -> TcRn m ()
1138 = do { dflags <- getDOpts ;
1140 -- Dump short output if -ddump-types or -ddump-tc
1141 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1142 (dumpTcRn short_dump) ;
1144 -- Dump bindings if -ddump-tc
1145 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1148 short_dump = pprTcGblEnv env
1149 full_dump = ppr (tcg_binds env)
1150 -- NB: foreign x-d's have undefined's in their types;
1151 -- hence can't show the tc_fords
1154 = do { dflags <- getDOpts ;
1155 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1156 (dumpTcRn (pprModGuts mod_guts)) ;
1158 -- Dump bindings if -ddump-tc
1159 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1161 full_dump = pprCoreBindings (mg_binds mod_guts)
1163 -- It's unpleasant having both pprModGuts and pprModDetails here
1164 pprTcGblEnv :: TcGblEnv -> SDoc
1165 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1166 tcg_insts = dfun_ids,
1167 tcg_rules = rules })
1168 = vcat [ ppr_types dfun_ids type_env
1169 , ppr_insts dfun_ids
1170 , vcat (map ppr rules)
1171 , ppr_gen_tycons (typeEnvTyCons type_env)]
1173 pprModGuts :: ModGuts -> SDoc
1174 pprModGuts (ModGuts { mg_types = type_env,
1176 = vcat [ ppr_types [] type_env,
1180 ppr_types :: [Var] -> TypeEnv -> SDoc
1181 ppr_types dfun_ids type_env
1182 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1184 ids = [id | id <- typeEnvIds type_env, want_sig id]
1185 want_sig id | opt_PprStyle_Debug = True
1186 | otherwise = isLocalId id &&
1187 isExternalName (idName id) &&
1188 not (id `elem` dfun_ids)
1189 -- isLocalId ignores data constructors, records selectors etc.
1190 -- The isExternalName ignores local dictionary and method bindings
1191 -- that the type checker has invented. Top-level user-defined things
1192 -- have External names.
1194 ppr_insts :: [Var] -> SDoc
1195 ppr_insts [] = empty
1196 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1198 ppr_sigs :: [Var] -> SDoc
1200 -- Print type signatures
1201 -- Convert to HsType so that we get source-language style printing
1202 -- And sort by RdrName
1203 = vcat $ map ppr_sig $ sortLt lt_sig $
1204 [ (getRdrName id, toHsType (idType id))
1207 lt_sig (n1,_) (n2,_) = n1 < n2
1208 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
1211 ppr_rules :: [IdCoreRule] -> SDoc
1212 ppr_rules [] = empty
1213 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1214 nest 4 (pprIdRules rs),
1217 ppr_gen_tycons [] = empty
1218 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
1219 vcat (map ppr_gen_tycon tcs),
1223 -- x&y are now Id's, not CoreExpr's
1225 | Just ep <- tyConGenInfo tycon
1226 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
1228 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
1231 = vcat [ ptext SLIT("Rep type:") <+> ppr (tcFunResultTy from_tau),
1232 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
1233 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
1236 (_,from_tau) = tcSplitForAllTys (idType from)