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,
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, plusGlobalRdrEnv )
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 {
604 -- Rename the splice expression, and get its supporting decls
605 (rn_splice_expr, fvs) <- initRn SourceMode (rnExpr splice_expr) ;
606 tcg_env <- importSupportingDecls fvs ;
607 setGblEnv tcg_env $ do {
609 -- Execute the splice
610 spliced_decls <- tcSpliceDecls rn_splice_expr ;
612 -- Glue them on the front of the remaining decls and loop
613 (tcg_env, src_fvs2) <- tcRnSrcDecls (spliced_decls ++ rest_ds) ;
615 return (tcg_env, src_fvs1 `plusFV` src_fvs2)
620 %************************************************************************
622 Type-checking the top level of a module
624 %************************************************************************
626 tcRnGroup takes a bunch of top-level source-code declarations, and
628 * gets supporting declarations from interface files
631 * and augments the TcGblEnv with the results
633 In Template Haskell it may be called repeatedly for each group of
634 declarations. It expects there to be an incoming TcGblEnv in the
635 monad; it augments it and returns the new TcGblEnv.
638 tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, FreeVars)
639 -- Returns the variables free in the decls
641 = do { -- Rename the declarations
642 (tcg_env, rn_decls, src_fvs) <- rnTopSrcDecls decls ;
643 setGblEnv tcg_env $ do {
645 -- Typecheck the declarations
646 tcg_env <- tcTopSrcDecls rn_decls ;
647 return (tcg_env, src_fvs)
650 ------------------------------------------------
651 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name, FreeVars)
653 = do { -- Bring top level binders into scope
654 (rdr_env, imports) <- importsFromLocalDecls group ;
655 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv`
657 tcg_imports = imports `plusImportAvails`
661 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
663 -- Rename the source decls
664 (tcg_env, rn_src_decls, src_fvs) <- initRn SourceMode (rnSrcDecls group) ;
665 setGblEnv tcg_env $ do {
669 -- Import consquential imports
670 rn_imp_decls <- slurpImpDecls (src_fvs `plusFV` implicitModuleFVs src_fvs) ;
671 let { rn_decls = rn_src_decls `addImpDecls` rn_imp_decls } ;
673 -- Dump trace of renaming part
674 rnDump (ppr rn_decls) ;
675 rnStats rn_imp_decls ;
677 return (tcg_env, rn_decls, src_fvs)
680 ------------------------------------------------
681 tcTopSrcDecls :: HsGroup Name -> TcM TcGblEnv
682 tcTopSrcDecls rn_decls
683 = fixM (\ unf_env -> do {
684 -- Loop back the final environment, including the fully zonked
685 -- versions of bindings from this module. In the presence of mutual
686 -- recursion, interface type signatures may mention variables defined
687 -- in this module, which is why the knot is so big
690 ((tcg_env, binds, rules, fords), lie) <- getLIE (
691 tc_src_decls unf_env rn_decls
694 -- tcSimplifyTop deals with constant or ambiguous InstIds.
695 -- How could there be ambiguous ones? They can only arise if a
696 -- top-level decl falls under the monomorphism
697 -- restriction, and no subsequent decl instantiates its
698 -- type. (Usually, ambiguous type variables are resolved
699 -- during the generalisation step.)
700 traceTc (text "Tc8") ;
701 inst_binds <- setGblEnv tcg_env (tcSimplifyTop lie) ;
702 -- The setGblEnv exposes the instances to tcSimplifyTop
704 -- Backsubstitution. This must be done last.
705 -- Even tcSimplifyTop may do some unification.
706 traceTc (text "Tc9") ;
707 (ids, binds', fords', rules') <- zonkTopDecls (binds `andMonoBinds` inst_binds)
710 let { tcg_env' = tcg_env { tcg_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) ids,
711 tcg_binds = tcg_binds tcg_env `andMonoBinds` binds',
712 tcg_rules = tcg_rules tcg_env ++ rules',
713 tcg_fords = tcg_fords tcg_env ++ fords' } } ;
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 traceTc (text "Tc2") ;
727 tcg_env <- tcTyClDecls unf_env tycl_decls ;
728 setGblEnv tcg_env $ do {
730 -- Source-language instances, including derivings,
731 -- and import the supporting declarations
732 traceTc (text "Tc3") ;
733 (tcg_env, inst_infos, deriv_binds, fvs) <- tcInstDecls1 tycl_decls inst_decls ;
734 setGblEnv tcg_env $ do {
735 tcg_env <- importSupportingDecls fvs ;
736 setGblEnv tcg_env $ do {
738 -- Foreign import declarations next. No zonking necessary
739 -- here; we can tuck them straight into the global environment.
740 traceTc (text "Tc4") ;
741 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
742 tcExtendGlobalValEnv fi_ids $
743 updGblEnv (\gbl -> gbl { tcg_fords = tcg_fords gbl ++ fi_decls })
746 -- Default declarations
747 traceTc (text "Tc4a") ;
748 default_tys <- tcDefaults default_decls ;
749 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
751 -- Value declarations next
752 -- We also typecheck any extra binds that came out
753 -- of the "deriving" process
754 traceTc (text "Tc5") ;
755 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds `ThenBinds` deriv_binds) ;
756 setLclTypeEnv lcl_env $ do {
758 -- Second pass over class and instance declarations,
759 -- plus rules and foreign exports, to generate bindings
760 traceTc (text "Tc6") ;
761 (cls_dm_binds, dm_ids) <- tcClassDecls2 tycl_decls ;
762 tcExtendGlobalValEnv dm_ids $ do {
763 inst_binds <- tcInstDecls2 inst_infos ;
764 showLIE "after instDecls2" ;
767 -- They need to be zonked, so we return them
768 traceTc (text "Tc7") ;
769 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
772 -- Need to partition them because the source rules
773 -- must be zonked before adding them to tcg_rules
774 -- NB: built-in rules come in as IfaceRuleOut's, and
775 -- get added to tcg_rules right here by tcExtendRules
776 rules <- tcRules rule_decls ;
777 let { (src_rules, iface_rules) = partition isSrcRule rules } ;
778 tcExtendRules iface_rules $ do {
781 tcg_env <- getGblEnv ;
782 let { all_binds = tc_val_binds `AndMonoBinds`
783 inst_binds `AndMonoBinds`
784 cls_dm_binds `AndMonoBinds`
787 return (tcg_env, all_binds, src_rules, foe_decls)
792 tcTyClDecls :: RecTcGblEnv
796 -- tcTyClDecls deals with
797 -- type and class decls (some source, some imported)
798 -- interface signatures (checked lazily)
800 -- It returns the TcGblEnv for this module, and side-effects the
801 -- persistent compiler state to reflect the things imported from
804 tcTyClDecls unf_env tycl_decls
805 -- (unf_env :: RecTcGblEnv) is used for type-checking interface pragmas
806 -- which is done lazily [ie failure just drops the pragma
807 -- without having any global-failure effect].
810 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
811 -- an error we'd better stop now, to avoid a cascade
813 traceTc (text "TyCl1") `thenM_`
814 tcTyAndClassDecls tycl_decls `thenM` \ tycl_things ->
815 tcExtendGlobalEnv tycl_things $
817 -- Interface type signatures
818 -- We tie a knot so that the Ids read out of interfaces are in scope
819 -- when we read their pragmas.
820 -- What we rely on is that pragmas are typechecked lazily; if
821 -- any type errors are found (ie there's an inconsistency)
822 -- we silently discard the pragma
823 traceTc (text "TyCl2") `thenM_`
824 tcInterfaceSigs unf_env tycl_decls `thenM` \ sig_ids ->
825 tcExtendGlobalValEnv sig_ids $
827 getGblEnv -- Return the TcLocals environment
832 %************************************************************************
834 Load the old interface file for this module (unless
835 we have it aleady), and check whether it is up to date
838 %************************************************************************
841 checkOldIface :: HscEnv
842 -> PersistentCompilerState
844 -> FilePath -- Where the interface file is
845 -> Bool -- Source unchanged
846 -> Maybe ModIface -- Old interface from compilation manager, if any
847 -> IO (PersistentCompilerState, Maybe (RecompileRequired, Maybe ModIface))
848 -- Nothing <=> errors happened
850 checkOldIface hsc_env pcs mod iface_path source_unchanged maybe_iface
851 = do { showPass (hsc_dflags hsc_env)
852 ("Checking old interface for " ++ moduleUserString mod) ;
854 initTc hsc_env pcs mod
855 (check_old_iface iface_path source_unchanged maybe_iface)
858 check_old_iface iface_path source_unchanged maybe_iface
859 = -- CHECK WHETHER THE SOURCE HAS CHANGED
860 ifM (not source_unchanged)
861 (traceHiDiffs (nest 4 (text "Source file changed or recompilation check turned off")))
864 -- If the source has changed and we're in interactive mode, avoid reading
865 -- an interface; just return the one we might have been supplied with.
866 getGhciMode `thenM` \ ghci_mode ->
867 if (ghci_mode == Interactive) && not source_unchanged then
868 returnM (outOfDate, maybe_iface)
872 Just old_iface -> -- Use the one we already have
873 checkVersions source_unchanged old_iface `thenM` \ recomp ->
874 returnM (recomp, Just old_iface)
876 Nothing -- Try and read it from a file
877 -> getModule `thenM` \ this_mod ->
878 readIface this_mod iface_path False `thenM` \ read_result ->
880 Left err -> -- Old interface file not found, or garbled; give up
882 text "Cannot read old interface file:"
883 $$ nest 4 (text (showException err))) `thenM_`
884 returnM (outOfDate, Nothing)
886 Right parsed_iface ->
887 initRn (InterfaceMode this_mod)
888 (loadOldIface parsed_iface) `thenM` \ m_iface ->
889 checkVersions source_unchanged m_iface `thenM` \ recomp ->
890 returnM (recomp, Just m_iface)
894 %************************************************************************
896 Type-check and rename supporting declarations
897 This is used to deal with the free vars of a splice,
898 or derived code: slurp in the necessary declarations,
899 typecheck them, and add them to the EPS
901 %************************************************************************
904 importSupportingDecls :: FreeVars -> TcM TcGblEnv
905 -- Completely deal with the supporting imports needed
906 -- by the specified free-var set
907 importSupportingDecls fvs
908 = do { traceRn (text "Import supporting decls for" <+> ppr (nameSetToList fvs)) ;
909 decls <- slurpImpDecls fvs ;
910 traceRn (text "...namely:" <+> vcat (map ppr decls)) ;
911 typecheckIfaceDecls (mkGroup decls) }
913 typecheckIfaceDecls :: HsGroup Name -> TcM TcGblEnv
914 -- The decls are all interface-file declarations
915 -- Usually they are all from other modules, but when we are reading
916 -- this module's interface from a file, it's possible that some of
917 -- them are for the module being compiled.
918 -- That is why the tcExtendX functions need to do partitioning.
920 -- If all the decls are from other modules, the returned TcGblEnv
921 -- will have an empty tc_genv, but its tc_inst_env and tc_ist
922 -- caches may have been augmented.
923 typecheckIfaceDecls (HsGroup { hs_tyclds = tycl_decls,
924 hs_instds = inst_decls,
925 hs_ruleds = rule_decls })
926 = do { -- Typecheck the type, class, and interface-sig decls
927 tcg_env <- fixM (\ unf_env -> tcTyClDecls unf_env tycl_decls) ;
928 setGblEnv tcg_env $ do {
930 -- Typecheck the instance decls, and rules
931 -- Note that imported dictionary functions are already
932 -- in scope from the preceding tcTyClDecls
933 tcIfaceInstDecls inst_decls `thenM` \ dfuns ->
934 tcExtendInstEnv dfuns $
935 tcRules rule_decls `thenM` \ rules ->
936 tcExtendRules rules $
938 getGblEnv -- Return the environment
944 %*********************************************************
946 mkGlobalContext: make up an interactive context
948 Used for initialising the lexical environment
949 of the interactive read-eval-print loop
951 %*********************************************************
956 :: HscEnv -> PersistentCompilerState
957 -> [Module] -- Expose these modules' top-level scope
958 -> [Module] -- Expose these modules' exports only
959 -> IO (PersistentCompilerState, Maybe GlobalRdrEnv)
961 mkGlobalContext hsc_env pcs toplevs exports
962 = initTc hsc_env pcs iNTERACTIVE $ do {
964 toplev_envs <- mappM getTopLevScope toplevs ;
965 export_envs <- mappM getModuleExports exports ;
966 returnM (foldr plusGlobalRdrEnv emptyGlobalRdrEnv
967 (toplev_envs ++ export_envs))
970 getTopLevScope :: Module -> TcRn m GlobalRdrEnv
972 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
973 case mi_globals iface of
974 Nothing -> panic "getTopLevScope"
975 Just env -> returnM env }
977 getModuleExports :: Module -> TcRn m GlobalRdrEnv
979 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
980 returnM (foldl add emptyGlobalRdrEnv (mi_exports iface)) }
982 prov_fn n = NonLocalDef ImplicitImport
984 = plusGlobalRdrEnv env (mkGlobalRdrEnv mod True prov_fn avails NoDeprecs)
986 contextDoc = text "context for compiling statements"
992 -> PersistentCompilerState -- IN: persistent compiler state
993 -> Module -- module to inspect
994 -> Bool -- grab just the exports, or the whole toplev
995 -> IO (PersistentCompilerState, Maybe [TyThing])
997 getModuleContents hsc_env pcs mod exports_only
998 = initTc hsc_env pcs iNTERACTIVE $ do {
1000 -- Load the interface if necessary (a home module will certainly
1001 -- alraedy be loaded, but a package module might not be)
1002 iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
1004 let { export_names = availsToNameSet export_avails ;
1005 export_avails = [ avail | (mn, avails) <- mi_exports iface,
1006 avail <- avails ] } ;
1008 all_names <- if exports_only then
1010 else case mi_globals iface of {
1012 return (get_locals rdr_env) ;
1014 Nothing -> do { addErr (noRdrEnvErr mod) ;
1015 return export_names } } ;
1016 -- Invariant; we only have (not exports_only)
1017 -- for a home module so it must already be in the HIT
1018 -- So the Nothing case is a bug
1020 env <- importSupportingDecls all_names ;
1021 setGblEnv env (mappM tcLookupGlobal (nameSetToList all_names))
1024 -- Grab all the things from the global env that are locally def'd
1025 get_locals rdr_env = mkNameSet [ gre_name gre
1026 | elts <- rdrEnvElts rdr_env,
1029 -- Make a set because a name is often in the envt in
1030 -- both qualified and unqualified forms
1032 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1033 <+> quotes (ppr mod)
1037 %************************************************************************
1041 %************************************************************************
1045 = do { ghci_mode <- getGhciMode ;
1046 tcg_env <- getGblEnv ;
1047 check_main ghci_mode tcg_env
1050 check_main ghci_mode tcg_env
1051 -- If we are in module Main, check that 'main' is defined.
1052 -- It may be imported from another module, in which case
1053 -- we have to drag in its.
1055 -- Also form the definition
1056 -- $main = runIO main
1057 -- so we need to slurp in runIO too.
1059 -- ToDo: We have to return the main_name separately, because it's a
1060 -- bona fide 'use', and should be recorded as such, but the others
1063 -- Blimey: a whole page of code to do this...
1065 | mod_name /= mAIN_Name
1066 = return (tcg_env, emptyFVs)
1068 | not (main_RDR_Unqual `elemRdrEnv` rdr_env)
1069 = do { complain_no_main; return (tcg_env, emptyFVs) }
1072 = do { -- Check that 'main' is in scope
1073 -- It might be imported from another module!
1074 main_name <- lookupSrcName main_RDR_Unqual ;
1077 tcg_env <- importSupportingDecls (unitFV runIOName) ;
1078 setGblEnv tcg_env $ do {
1080 -- $main :: IO () = runIO main
1081 let { rhs = HsApp (HsVar runIOName) (HsVar main_name) } ;
1083 (main_bind, top_lie) <- getLIE (
1084 addSrcLoc (getSrcLoc main_name) $
1085 addErrCtxt mainCtxt $ do {
1086 (main_expr, ty) <- tcExpr_id rhs ;
1087 let { dollar_main_id = setIdLocalExported (mkLocalId dollarMainName ty) } ;
1088 return (VarMonoBind dollar_main_id main_expr)
1091 inst_binds <- tcSimplifyTop top_lie ;
1093 (ids, binds') <- zonkTopBinds (main_bind `andMonoBinds` inst_binds) ;
1095 let { tcg_env' = tcg_env {
1096 tcg_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) ids,
1097 tcg_binds = tcg_binds tcg_env `andMonoBinds` binds' } } ;
1099 return (tcg_env', unitFV main_name)
1102 mod_name = moduleName (tcg_mod tcg_env)
1103 rdr_env = tcg_rdr_env tcg_env
1105 main_RDR_Unqual :: RdrName
1106 main_RDR_Unqual = mkUnqual varName FSLIT("main")
1107 -- Don't get a RdrName from PrelNames.mainName, because
1108 -- nameRdrNamegets an Orig RdrName, and we want a Qual or Unqual one.
1109 -- An Unqual one will do just fine
1111 complain_no_main | ghci_mode == Interactive = return ()
1112 | otherwise = addErr noMainMsg
1113 -- In interactive mode, don't worry about the absence of 'main'
1115 mainCtxt = ptext SLIT("When checking the type of 'main'")
1116 noMainMsg = ptext SLIT("No 'main' defined in module Main")
1120 %************************************************************************
1124 %************************************************************************
1127 rnDump :: SDoc -> TcRn m ()
1128 -- Dump, with a banner, if -ddump-rn
1129 rnDump doc = dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc)
1131 tcDump :: TcGblEnv -> TcRn m ()
1133 = do { dflags <- getDOpts ;
1135 -- Dump short output if -ddump-types or -ddump-tc
1136 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1137 (dumpTcRn short_dump) ;
1139 -- Dump bindings if -ddump-tc
1140 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1143 short_dump = pprTcGblEnv env
1144 full_dump = ppr (tcg_binds env)
1145 -- NB: foreign x-d's have undefined's in their types;
1146 -- hence can't show the tc_fords
1149 = do { dflags <- getDOpts ;
1150 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1151 (dumpTcRn (pprModGuts mod_guts)) ;
1153 -- Dump bindings if -ddump-tc
1154 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1156 full_dump = pprCoreBindings (mg_binds mod_guts)
1158 -- It's unpleasant having both pprModGuts and pprModDetails here
1159 pprTcGblEnv :: TcGblEnv -> SDoc
1160 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1161 tcg_insts = dfun_ids,
1162 tcg_rules = rules })
1163 = vcat [ ppr_types dfun_ids type_env
1164 , ppr_insts dfun_ids
1165 , vcat (map ppr rules)
1166 , ppr_gen_tycons (typeEnvTyCons type_env)]
1168 pprModGuts :: ModGuts -> SDoc
1169 pprModGuts (ModGuts { mg_types = type_env,
1171 = vcat [ ppr_types [] type_env,
1175 ppr_types :: [Var] -> TypeEnv -> SDoc
1176 ppr_types dfun_ids type_env
1177 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1179 ids = [id | id <- typeEnvIds type_env, want_sig id]
1180 want_sig id | opt_PprStyle_Debug = True
1181 | otherwise = isLocalId id &&
1182 isExternalName (idName id) &&
1183 not (id `elem` dfun_ids)
1184 -- isLocalId ignores data constructors, records selectors etc.
1185 -- The isExternalName ignores local dictionary and method bindings
1186 -- that the type checker has invented. Top-level user-defined things
1187 -- have External names.
1189 ppr_insts :: [Var] -> SDoc
1190 ppr_insts [] = empty
1191 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1193 ppr_sigs :: [Var] -> SDoc
1195 -- Print type signatures
1196 -- Convert to HsType so that we get source-language style printing
1197 -- And sort by RdrName
1198 = vcat $ map ppr_sig $ sortLt lt_sig $
1199 [ (getRdrName id, toHsType (idType id))
1202 lt_sig (n1,_) (n2,_) = n1 < n2
1203 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
1206 ppr_rules :: [IdCoreRule] -> SDoc
1207 ppr_rules [] = empty
1208 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1209 nest 4 (pprIdRules rs),
1212 ppr_gen_tycons [] = empty
1213 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
1214 vcat (map ppr_gen_tycon tcs),
1218 -- x&y are now Id's, not CoreExpr's
1220 | Just ep <- tyConGenInfo tycon
1221 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
1223 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
1226 = vcat [ ptext SLIT("Rep type:") <+> ppr (tcFunResultTy from_tau),
1227 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
1228 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
1231 (_,from_tau) = tcSplitForAllTys (idType from)