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 )
20 import DsMeta ( templateHaskellNames )
23 import CmdLineOpts ( DynFlag(..), opt_PprStyle_Debug, dopt )
24 import HsSyn ( HsModule(..), HsBinds(..), MonoBinds(..), HsExpr(..),
25 Stmt(..), Pat(VarPat), HsStmtContext(..), RuleDecl(..),
26 HsGroup(..), SpliceDecl(..),
27 mkSimpleMatch, placeHolderType, toHsType, andMonoBinds,
28 isSrcRule, collectStmtsBinders
30 import RdrHsSyn ( RdrNameHsModule, RdrNameHsDecl, RdrNameStmt, RdrNameHsExpr,
31 emptyGroup, mkGroup, findSplice, addImpDecls )
33 import PrelNames ( iNTERACTIVE, ioTyConName, printName,
34 returnIOName, bindIOName, failIOName, thenIOName, runIOName,
35 dollarMainName, itName, mAIN_Name
37 import MkId ( unsafeCoerceId )
38 import RdrName ( RdrName, getRdrName, mkRdrUnqual,
39 lookupRdrEnv, elemRdrEnv )
41 import RnHsSyn ( RenamedStmt, RenamedTyClDecl,
42 ruleDeclFVs, instDeclFVs, tyClDeclFVs )
43 import TcHsSyn ( TypecheckedHsExpr, TypecheckedRuleDecl,
44 zonkTopBinds, zonkTopDecls, mkHsLet,
45 zonkTopExpr, zonkTopBndrs
48 import TcExpr ( tcExpr_id )
50 import TcMType ( newTyVarTy, zonkTcType )
51 import TcType ( Type, liftedTypeKind,
52 tyVarsOfType, tcFunResultTy,
53 mkForAllTys, mkFunTys, mkTyConApp, tcSplitForAllTys
55 import TcMatches ( tcStmtsAndThen )
56 import Inst ( showLIE )
57 import TcBinds ( tcTopBinds )
58 import TcClassDcl ( tcClassDecls2 )
59 import TcDefaults ( tcDefaults )
60 import TcEnv ( tcExtendGlobalValEnv,
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 ( importsFromLocalDecls, rnImports, exportsFromAvail,
74 reportUnusedNames, main_RDR_Unqual )
75 import RnIfaces ( slurpImpDecls, checkVersions, RecompileRequired, outOfDate )
76 import RnHiFiles ( readIface, loadOldIface )
77 import RnEnv ( lookupSrcName, lookupOccRn, plusGlobalRdrEnv,
78 ubiquitousNames, implicitModuleFVs, implicitStmtFVs, dataTcOccs )
79 import RnExpr ( rnStmts, rnExpr )
80 import RnSource ( rnSrcDecls, checkModDeprec, rnStats )
82 import CoreUnfold ( unfoldingTemplate )
83 import CoreSyn ( IdCoreRule, Bind(..) )
84 import PprCore ( pprIdRules, pprCoreBindings )
85 import TysWiredIn ( mkListTy, unitTy )
86 import ErrUtils ( mkDumpDoc, showPass )
87 import Id ( Id, mkLocalId, isLocalId, idName, idType, idUnfolding, setIdLocalExported )
88 import IdInfo ( GlobalIdDetails(..) )
89 import Var ( Var, setGlobalIdDetails )
90 import Module ( Module, moduleName, moduleUserString, moduleEnvElts )
91 import Name ( Name, isExternalName, getSrcLoc, nameOccName )
92 import NameEnv ( delListFromNameEnv )
94 import TyCon ( tyConGenInfo )
95 import BasicTypes ( EP(..), RecFlag(..) )
96 import SrcLoc ( noSrcLoc )
98 import HscTypes ( PersistentCompilerState(..), InteractiveContext(..),
99 ModIface, ModDetails(..), ModGuts(..),
101 ModIface(..), ModDetails(..), IfaceDecls(..),
102 GhciMode(..), noDependencies,
103 Deprecations(..), plusDeprecs,
105 GenAvailInfo(Avail), availsToNameSet,
107 TypeEnv, TyThing, typeEnvTyCons,
108 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
109 extendLocalRdrEnv, emptyFixityEnv
112 import RdrName ( rdrEnvElts )
113 import RnHiFiles ( loadInterface )
114 import RnEnv ( mkGlobalRdrEnv )
115 import HscTypes ( GlobalRdrElt(..), GlobalRdrEnv, ImportReason(..), Provenance(..),
119 import Maybe ( catMaybes )
120 import Panic ( showException )
121 import List ( partition )
122 import Util ( sortLt )
127 %************************************************************************
129 Typecheck and rename a module
131 %************************************************************************
135 tcRnModule :: HscEnv -> PersistentCompilerState
137 -> IO (PersistentCompilerState, Maybe TcGblEnv)
139 tcRnModule hsc_env pcs
140 (HsModule this_mod _ exports import_decls local_decls mod_deprec loc)
141 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
143 initTc hsc_env pcs this_mod $ addSrcLoc loc $
144 do { -- Deal with imports; sets tcg_rdr_env, tcg_imports
145 (rdr_env, imports) <- rnImports import_decls ;
146 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
147 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
149 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
150 -- Fail if there are any errors so far
151 -- The error printing (if needed) takes advantage
152 -- of the tcg_env we have now set
155 traceRn (text "rn1a") ;
156 -- Rename and type check the declarations
157 (tcg_env, src_fvs) <- tcRnSrcDecls local_decls ;
158 setGblEnv tcg_env $ do {
160 traceRn (text "rn3") ;
161 -- Check whether the entire module is deprecated
162 -- This happens only once per module
163 -- Returns the full new deprecations; a module deprecation
164 -- over-rides the earlier ones
165 let { mod_deprecs = checkModDeprec mod_deprec } ;
166 updGblEnv (\gbl -> gbl { tcg_deprecs = tcg_deprecs gbl `plusDeprecs` mod_deprecs })
169 -- Process the export list
170 export_avails <- exportsFromAvail exports ;
171 updGblEnv (\gbl -> gbl { tcg_exports = export_avails })
174 -- Get any supporting decls for the exports that have not already
175 -- been sucked in for the declarations in the body of the module.
176 -- (This can happen if something is imported only to be re-exported.)
178 -- Importing these supporting declarations is required
179 -- *only* to gether usage information
180 -- (see comments with MkIface.mkImportInfo for why)
181 -- For OneShot compilation we could just throw away the decls
182 -- but for Batch or Interactive we must put them in the type
183 -- envt because they've been removed from the holding pen
184 let { export_fvs = availsToNameSet export_avails } ;
185 tcg_env <- importSupportingDecls export_fvs ;
186 setGblEnv tcg_env $ do {
188 -- Report unused names
189 let { used_fvs = src_fvs `plusFV` export_fvs } ;
190 reportUnusedNames tcg_env used_fvs ;
192 -- Dump output and return
199 %*********************************************************
201 \subsection{Closing up the interface decls}
203 %*********************************************************
205 Suppose we discover we don't need to recompile. Then we start from the
206 IfaceDecls in the ModIface, and fluff them up by sucking in all the decls they need.
210 -> PersistentCompilerState
211 -> ModIface -- Get the decls from here
212 -> IO (PersistentCompilerState, Maybe ModDetails)
213 -- Nothing <=> errors happened
214 tcRnIface hsc_env pcs
215 (ModIface {mi_module = mod, mi_decls = iface_decls})
216 = initTc hsc_env pcs mod $ do {
218 -- Get the supporting decls, and typecheck them all together
219 -- so that any mutually recursive types are done right
220 extra_decls <- slurpImpDecls needed ;
221 env <- typecheckIfaceDecls (group `addImpDecls` extra_decls) ;
223 returnM (ModDetails { md_types = tcg_type_env env,
224 md_insts = tcg_insts env,
225 md_rules = hsCoreRules (tcg_rules env)
226 -- All the rules from an interface are of the IfaceRuleOut form
229 rule_decls = dcl_rules iface_decls
230 inst_decls = dcl_insts iface_decls
231 tycl_decls = dcl_tycl iface_decls
232 group = emptyGroup { hs_ruleds = rule_decls,
233 hs_instds = inst_decls,
234 hs_tyclds = tycl_decls }
235 needed = unionManyNameSets (map ruleDeclFVs rule_decls) `unionNameSets`
236 unionManyNameSets (map instDeclFVs inst_decls) `unionNameSets`
237 unionManyNameSets (map tyClDeclFVs tycl_decls) `unionNameSets`
239 -- Data type decls with record selectors,
240 -- which may appear in the decls, need unpackCString
241 -- and friends. It's easier to just grab them right now.
243 hsCoreRules :: [TypecheckedRuleDecl] -> [IdCoreRule]
244 -- All post-typechecking Iface rules have the form IfaceRuleOut
245 hsCoreRules rules = [(id,rule) | IfaceRuleOut id rule <- rules]
249 %************************************************************************
251 The interactive interface
253 %************************************************************************
256 tcRnStmt :: HscEnv -> PersistentCompilerState
257 -> InteractiveContext
259 -> IO (PersistentCompilerState,
260 Maybe (InteractiveContext, [Name], TypecheckedHsExpr))
261 -- The returned [Name] is the same as the input except for
262 -- ExprStmt, in which case the returned [Name] is [itName]
264 -- The returned TypecheckedHsExpr is of type IO [ () ],
265 -- a list of the bound values, coerced to ().
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 -- Add deprecation warnings
490 mapM_ addMessages msgs_s ;
492 -- Slurp in the supporting declarations
493 tcg_env <- importSupportingDecls (mkFVs names) ;
494 setGblEnv tcg_env $ do {
496 -- And lookup up the entities
497 mapM tcLookupGlobal names
503 setInteractiveContext :: InteractiveContext -> TcRn m a -> TcRn m a
504 setInteractiveContext icxt thing_inside
505 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
506 updGblEnv (\ env -> env { tcg_rdr_env = ic_rn_gbl_env icxt,
507 tcg_type_env = ic_type_env icxt })
510 initRnInteractive :: InteractiveContext -> RnM a -> TcM a
511 -- Set the local RdrEnv from the interactive context
512 initRnInteractive ictxt rn_thing
513 = initRn CmdLineMode $
514 setLocalRdrEnv (ic_rn_local_env ictxt) $
518 %************************************************************************
520 Type-checking external-core modules
522 %************************************************************************
525 tcRnExtCore :: HscEnv -> PersistentCompilerState
527 -> IO (PersistentCompilerState, Maybe ModGuts)
528 -- Nothing => some error occurred
530 tcRnExtCore hsc_env pcs
531 (HsModule this_mod _ _ _ local_decls _ loc)
532 -- Rename the (Core) module. It's a bit like an interface
533 -- file: all names are original names
534 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
536 initTc hsc_env pcs this_mod $ addSrcLoc loc $ do {
538 -- Rename the source, only in interface mode.
539 -- rnSrcDecls handles fixity decls etc too, which won't occur
540 -- but that doesn't matter
541 let { local_group = mkGroup local_decls } ;
542 (_, rn_local_decls, fvs) <- initRn (InterfaceMode this_mod)
543 (rnSrcDecls local_group) ;
546 -- Get the supporting decls, and typecheck them all together
547 -- so that any mutually recursive types are done right
548 extra_decls <- slurpImpDecls fvs ;
549 tcg_env <- typecheckIfaceDecls (rn_local_decls `addImpDecls` extra_decls) ;
550 setGblEnv tcg_env $ do {
552 -- Now the core bindings
553 core_prs <- tcCoreBinds (hs_coreds rn_local_decls) ;
554 tcExtendGlobalValEnv (map fst core_prs) $ do {
558 bndrs = map fst core_prs ;
559 my_exports = map (Avail . idName) bndrs ;
560 -- ToDo: export the data types also?
562 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
564 mod_guts = ModGuts { mg_module = this_mod,
565 mg_usages = [], -- ToDo: compute usage
566 mg_dir_imps = [], -- ??
567 mg_deps = noDependencies, -- ??
568 mg_exports = my_exports,
569 mg_types = final_type_env,
570 mg_insts = tcg_insts tcg_env,
571 mg_rules = hsCoreRules (tcg_rules tcg_env),
572 mg_binds = [Rec core_prs],
575 mg_rdr_env = emptyGlobalRdrEnv,
576 mg_fix_env = emptyFixityEnv,
577 mg_deprecs = NoDeprecs,
581 tcCoreDump mod_guts ;
588 %************************************************************************
590 Type-checking the top level of a module
592 %************************************************************************
595 tcRnSrcDecls :: [RdrNameHsDecl] -> TcM (TcGblEnv, FreeVars)
596 -- Returns the variables free in the decls
597 -- Reason: solely to report unused imports and bindings
600 = do { -- Do all the declarations
601 ((tc_envs, fvs), lie) <- getLIE (tc_rn_src_decls decls) ;
603 -- tcSimplifyTop deals with constant or ambiguous InstIds.
604 -- How could there be ambiguous ones? They can only arise if a
605 -- top-level decl falls under the monomorphism
606 -- restriction, and no subsequent decl instantiates its
607 -- type. (Usually, ambiguous type variables are resolved
608 -- during the generalisation step.)
609 traceTc (text "Tc8") ;
610 setEnvs tc_envs $ do {
611 -- Setting the global env exposes the instances to tcSimplifyTop
612 -- Setting the local env exposes the local Ids, so that
613 -- we get better error messages (monomorphism restriction)
614 inst_binds <- tcSimplifyTop lie ;
616 -- Backsubstitution. This must be done last.
617 -- Even tcSimplifyTop may do some unification.
618 traceTc (text "Tc9") ;
619 let { (tcg_env, _) = tc_envs ;
620 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
621 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
623 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `andMonoBinds` inst_binds)
626 return (tcg_env { tcg_type_env = extendTypeEnvWithIds type_env bind_ids,
627 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' },
631 tc_rn_src_decls :: [RdrNameHsDecl] -> TcM ((TcGblEnv, TcLclEnv), FreeVars)
634 = do { let { (first_group, group_tail) = findSplice ds } ;
635 -- If ds is [] we get ([], Nothing)
637 -- Type check the decls up to, but not including, the first splice
638 (tc_envs@(_,tcl_env), src_fvs1) <- tcRnGroup first_group ;
640 -- Bale out if errors; for example, error recovery when checking
641 -- the RHS of 'main' can mean that 'main' is not in the envt for
642 -- the subsequent checkMain test
647 -- If there is no splice, we're nearlydone
649 Nothing -> do { -- Last thing: check for `main'
650 (tcg_env, main_fvs) <- checkMain ;
651 return ((tcg_env, tcl_env), src_fvs1 `plusFV` main_fvs)
654 -- If there's a splice, we must carry on
655 Just (SpliceDecl splice_expr splice_loc, rest_ds) -> do {
657 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
660 -- Rename the splice expression, and get its supporting decls
661 (rn_splice_expr, fvs) <- initRn SourceMode $
662 addSrcLoc splice_loc $
664 tcg_env <- importSupportingDecls (fvs `plusFV` templateHaskellNames) ;
665 setGblEnv tcg_env $ do {
667 -- Execute the splice
668 spliced_decls <- tcSpliceDecls rn_splice_expr ;
670 -- Glue them on the front of the remaining decls and loop
671 (tc_envs, src_fvs2) <- tc_rn_src_decls (spliced_decls ++ rest_ds) ;
673 return (tc_envs, src_fvs1 `plusFV` src_fvs2)
680 %************************************************************************
682 Type-checking the top level of a module
684 %************************************************************************
686 tcRnGroup takes a bunch of top-level source-code declarations, and
688 * gets supporting declarations from interface files
691 * and augments the TcGblEnv with the results
693 In Template Haskell it may be called repeatedly for each group of
694 declarations. It expects there to be an incoming TcGblEnv in the
695 monad; it augments it and returns the new TcGblEnv.
698 tcRnGroup :: HsGroup RdrName -> TcM ((TcGblEnv, TcLclEnv), FreeVars)
699 -- Returns the variables free in the decls, for unused-binding reporting
701 = do { -- Rename the declarations
702 (tcg_env, rn_decls, src_fvs) <- rnTopSrcDecls decls ;
703 setGblEnv tcg_env $ do {
705 -- Typecheck the declarations
706 tc_envs <- tcTopSrcDecls rn_decls ;
707 return (tc_envs, src_fvs)
710 ------------------------------------------------
711 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name, FreeVars)
713 = do { -- Bring top level binders into scope
714 (rdr_env, imports) <- importsFromLocalDecls group ;
715 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv`
717 tcg_imports = imports `plusImportAvails`
721 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
723 -- Rename the source decls
724 (tcg_env, rn_src_decls, src_fvs) <- initRn SourceMode (rnSrcDecls group) ;
725 setGblEnv tcg_env $ do {
729 -- Import consquential imports
730 rn_imp_decls <- slurpImpDecls (src_fvs `plusFV` implicitModuleFVs src_fvs) ;
731 let { rn_decls = rn_src_decls `addImpDecls` rn_imp_decls } ;
733 -- Dump trace of renaming part
734 rnDump (ppr rn_decls) ;
735 rnStats rn_imp_decls ;
737 return (tcg_env, rn_decls, src_fvs)
740 ------------------------------------------------
741 tcTopSrcDecls :: HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
743 (HsGroup { hs_tyclds = tycl_decls,
744 hs_instds = inst_decls,
745 hs_fords = foreign_decls,
746 hs_defds = default_decls,
747 hs_ruleds = rule_decls,
748 hs_valds = val_binds })
749 = do { -- Type-check the type and class decls, and all imported decls
750 -- The latter come in via tycl_decls
751 traceTc (text "Tc2") ;
752 tcg_env <- tcTyClDecls tycl_decls ;
753 setGblEnv tcg_env $ do {
755 -- Source-language instances, including derivings,
756 -- and import the supporting declarations
757 traceTc (text "Tc3") ;
758 (tcg_env, inst_infos, deriv_binds, fvs) <- tcInstDecls1 tycl_decls inst_decls ;
759 setGblEnv tcg_env $ do {
760 tcg_env <- importSupportingDecls fvs ;
761 setGblEnv tcg_env $ do {
763 -- Foreign import declarations next. No zonking necessary
764 -- here; we can tuck them straight into the global environment.
765 traceTc (text "Tc4") ;
766 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
767 tcExtendGlobalValEnv fi_ids $
768 updGblEnv (\gbl -> gbl { tcg_fords = tcg_fords gbl ++ fi_decls })
771 -- Default declarations
772 traceTc (text "Tc4a") ;
773 default_tys <- tcDefaults default_decls ;
774 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
776 -- Value declarations next
777 -- We also typecheck any extra binds that came out
778 -- of the "deriving" process
779 traceTc (text "Tc5") ;
780 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds `ThenBinds` deriv_binds) ;
781 setLclTypeEnv lcl_env $ do {
783 -- Second pass over class and instance declarations,
784 -- plus rules and foreign exports, to generate bindings
785 traceTc (text "Tc6") ;
786 (cls_dm_binds, dm_ids) <- tcClassDecls2 tycl_decls ;
787 tcExtendGlobalValEnv dm_ids $ do {
788 inst_binds <- tcInstDecls2 inst_infos ;
789 showLIE "after instDecls2" ;
792 -- They need to be zonked, so we return them
793 traceTc (text "Tc7") ;
794 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
797 -- Need to partition them because the source rules
798 -- must be zonked before adding them to tcg_rules
799 -- NB: built-in rules come in as IfaceRuleOut's, and
800 -- get added to tcg_rules right here by tcExtendRules
801 rules <- tcRules rule_decls ;
802 let { (src_rules, iface_rules) = partition isSrcRule rules } ;
803 tcExtendRules iface_rules $ do {
806 tcg_env <- getGblEnv ;
807 let { all_binds = tc_val_binds `AndMonoBinds`
808 inst_binds `AndMonoBinds`
809 cls_dm_binds `AndMonoBinds`
812 -- Extend the GblEnv with the (as yet un-zonked)
813 -- bindings, rules, foreign decls
814 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `andMonoBinds` all_binds,
815 tcg_rules = tcg_rules tcg_env ++ src_rules,
816 tcg_fords = tcg_fords tcg_env ++ foe_decls } } ;
818 return (tcg_env', lcl_env)
823 tcTyClDecls :: [RenamedTyClDecl]
826 -- tcTyClDecls deals with
827 -- type and class decls (some source, some imported)
828 -- interface signatures (checked lazily)
830 -- It returns the TcGblEnv for this module, and side-effects the
831 -- persistent compiler state to reflect the things imported from
834 tcTyClDecls tycl_decls
836 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
837 -- an error we'd better stop now, to avoid a cascade
839 traceTc (text "TyCl1") `thenM_`
840 tcTyAndClassDecls tycl_decls `thenM` \ tcg_env ->
841 -- Returns the extended environment
844 traceTc (text "TyCl2") `thenM_`
845 tcInterfaceSigs tycl_decls `thenM` \ tcg_env ->
846 -- Returns the extended environment
853 %************************************************************************
855 Load the old interface file for this module (unless
856 we have it aleady), and check whether it is up to date
859 %************************************************************************
862 checkOldIface :: HscEnv
863 -> PersistentCompilerState
865 -> FilePath -- Where the interface file is
866 -> Bool -- Source unchanged
867 -> Maybe ModIface -- Old interface from compilation manager, if any
868 -> IO (PersistentCompilerState, Maybe (RecompileRequired, Maybe ModIface))
869 -- Nothing <=> errors happened
871 checkOldIface hsc_env pcs mod iface_path source_unchanged maybe_iface
872 = do { showPass (hsc_dflags hsc_env)
873 ("Checking old interface for " ++ moduleUserString mod) ;
875 initTc hsc_env pcs mod
876 (check_old_iface iface_path source_unchanged maybe_iface)
879 check_old_iface iface_path source_unchanged maybe_iface
880 = -- CHECK WHETHER THE SOURCE HAS CHANGED
881 ifM (not source_unchanged)
882 (traceHiDiffs (nest 4 (text "Source file changed or recompilation check turned off")))
885 -- If the source has changed and we're in interactive mode, avoid reading
886 -- an interface; just return the one we might have been supplied with.
887 getGhciMode `thenM` \ ghci_mode ->
888 if (ghci_mode == Interactive) && not source_unchanged then
889 returnM (outOfDate, maybe_iface)
893 Just old_iface -> -- Use the one we already have
894 checkVersions source_unchanged old_iface `thenM` \ recomp ->
895 returnM (recomp, Just old_iface)
897 Nothing -- Try and read it from a file
898 -> getModule `thenM` \ this_mod ->
899 readIface this_mod iface_path False `thenM` \ read_result ->
901 Left err -> -- Old interface file not found, or garbled; give up
903 text "Cannot read old interface file:"
904 $$ nest 4 (text (showException err))) `thenM_`
905 returnM (outOfDate, Nothing)
907 Right parsed_iface ->
908 initRn (InterfaceMode this_mod)
909 (loadOldIface parsed_iface) `thenM` \ m_iface ->
910 checkVersions source_unchanged m_iface `thenM` \ recomp ->
911 returnM (recomp, Just m_iface)
915 %************************************************************************
917 Type-check and rename supporting declarations
918 This is used to deal with the free vars of a splice,
919 or derived code: slurp in the necessary declarations,
920 typecheck them, and add them to the EPS
922 %************************************************************************
925 importSupportingDecls :: FreeVars -> TcM TcGblEnv
926 -- Completely deal with the supporting imports needed
927 -- by the specified free-var set
928 importSupportingDecls fvs
929 = do { traceRn (text "Import supporting decls for" <+> ppr (nameSetToList fvs)) ;
930 decls <- slurpImpDecls fvs ;
931 traceRn (text "...namely:" <+> vcat (map ppr decls)) ;
932 typecheckIfaceDecls (mkGroup decls) }
934 typecheckIfaceDecls :: HsGroup Name -> TcM TcGblEnv
935 -- The decls are all interface-file declarations
936 -- Usually they are all from other modules, but when we are reading
937 -- this module's interface from a file, it's possible that some of
938 -- them are for the module being compiled.
939 -- That is why the tcExtendX functions need to do partitioning.
941 -- If all the decls are from other modules, the returned TcGblEnv
942 -- will have an empty tc_genv, but its tc_inst_env
943 -- cache may have been augmented.
944 typecheckIfaceDecls (HsGroup { hs_tyclds = tycl_decls,
945 hs_instds = inst_decls,
946 hs_ruleds = rule_decls })
947 = do { -- Typecheck the type, class, and interface-sig decls
948 tcg_env <- tcTyClDecls tycl_decls ;
949 setGblEnv tcg_env $ do {
951 -- Typecheck the instance decls, and rules
952 -- Note that imported dictionary functions are already
953 -- in scope from the preceding tcTyClDecls
954 tcIfaceInstDecls inst_decls `thenM` \ dfuns ->
955 tcExtendInstEnv dfuns $
956 tcRules rule_decls `thenM` \ rules ->
957 tcExtendRules rules $
959 getGblEnv -- Return the environment
965 %*********************************************************
967 mkGlobalContext: make up an interactive context
969 Used for initialising the lexical environment
970 of the interactive read-eval-print loop
972 %*********************************************************
977 :: HscEnv -> PersistentCompilerState
978 -> [Module] -- Expose these modules' top-level scope
979 -> [Module] -- Expose these modules' exports only
980 -> IO (PersistentCompilerState, Maybe GlobalRdrEnv)
982 mkGlobalContext hsc_env pcs toplevs exports
983 = initTc hsc_env pcs iNTERACTIVE $ do {
985 toplev_envs <- mappM getTopLevScope toplevs ;
986 export_envs <- mappM getModuleExports exports ;
987 returnM (foldr plusGlobalRdrEnv emptyGlobalRdrEnv
988 (toplev_envs ++ export_envs))
991 getTopLevScope :: Module -> TcRn m GlobalRdrEnv
993 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
994 case mi_globals iface of
995 Nothing -> panic "getTopLevScope"
996 Just env -> returnM env }
998 getModuleExports :: Module -> TcRn m GlobalRdrEnv
1000 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
1001 returnM (foldl add emptyGlobalRdrEnv (mi_exports iface)) }
1003 prov_fn n = NonLocalDef ImplicitImport
1004 add env (mod,avails)
1005 = plusGlobalRdrEnv env (mkGlobalRdrEnv mod True prov_fn avails NoDeprecs)
1007 contextDoc = text "context for compiling statements"
1013 -> PersistentCompilerState -- IN: persistent compiler state
1014 -> Module -- module to inspect
1015 -> Bool -- grab just the exports, or the whole toplev
1016 -> IO (PersistentCompilerState, Maybe [TyThing])
1018 getModuleContents hsc_env pcs mod exports_only
1019 = initTc hsc_env pcs iNTERACTIVE $ do {
1021 -- Load the interface if necessary (a home module will certainly
1022 -- alraedy be loaded, but a package module might not be)
1023 iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
1025 let { export_names = availsToNameSet export_avails ;
1026 export_avails = [ avail | (mn, avails) <- mi_exports iface,
1027 avail <- avails ] } ;
1029 all_names <- if exports_only then
1031 else case mi_globals iface of {
1033 return (get_locals rdr_env) ;
1035 Nothing -> do { addErr (noRdrEnvErr mod) ;
1036 return export_names } } ;
1037 -- Invariant; we only have (not exports_only)
1038 -- for a home module so it must already be in the HIT
1039 -- So the Nothing case is a bug
1041 env <- importSupportingDecls all_names ;
1042 setGblEnv env (mappM tcLookupGlobal (nameSetToList all_names))
1045 -- Grab all the things from the global env that are locally def'd
1046 get_locals rdr_env = mkNameSet [ gre_name gre
1047 | elts <- rdrEnvElts rdr_env,
1050 -- Make a set because a name is often in the envt in
1051 -- both qualified and unqualified forms
1053 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1054 <+> quotes (ppr mod)
1058 %************************************************************************
1062 %************************************************************************
1066 = do { ghci_mode <- getGhciMode ;
1067 tcg_env <- getGblEnv ;
1068 check_main ghci_mode tcg_env
1071 check_main ghci_mode tcg_env
1072 -- If we are in module Main, check that 'main' is defined.
1073 -- It may be imported from another module, in which case
1074 -- we have to drag in its.
1076 -- Also form the definition
1077 -- $main = runIO main
1078 -- so we need to slurp in runIO too.
1080 -- ToDo: We have to return the main_name separately, because it's a
1081 -- bona fide 'use', and should be recorded as such, but the others
1084 -- Blimey: a whole page of code to do this...
1086 | mod_name /= mAIN_Name
1087 = return (tcg_env, emptyFVs)
1089 -- Check that 'main' is in scope
1090 -- It might be imported from another module!
1092 -- We use a guard for this (rather than letting lookupSrcName fail)
1093 -- because it's not an error in ghci)
1094 | not (main_RDR_Unqual `elemRdrEnv` rdr_env)
1095 = do { complain_no_main; return (tcg_env, emptyFVs) }
1098 = do { main_name <- lookupSrcName main_RDR_Unqual ;
1100 tcg_env <- importSupportingDecls (unitFV runIOName) ;
1102 addSrcLoc (getSrcLoc main_name) $
1103 addErrCtxt mainCtxt $
1104 setGblEnv tcg_env $ do {
1106 -- $main :: IO () = runIO main
1107 let { rhs = HsApp (HsVar runIOName) (HsVar main_name) } ;
1108 (main_expr, ty) <- tcExpr_id rhs ;
1110 let { dollar_main_id = setIdLocalExported (mkLocalId dollarMainName ty) ;
1111 main_bind = VarMonoBind dollar_main_id main_expr ;
1112 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env
1113 `andMonoBinds` main_bind } } ;
1115 return (tcg_env', unitFV main_name)
1118 mod_name = moduleName (tcg_mod tcg_env)
1119 rdr_env = tcg_rdr_env tcg_env
1121 complain_no_main | ghci_mode == Interactive = return ()
1122 | otherwise = failWithTc noMainMsg
1123 -- In interactive mode, don't worry about the absence of 'main'
1124 -- In other modes, fail altogether, so that we don't go on
1125 -- and complain a second time when processing the export list.
1127 mainCtxt = ptext SLIT("When checking the type of 'main'")
1128 noMainMsg = ptext SLIT("No 'main' defined in module Main")
1132 %************************************************************************
1136 %************************************************************************
1139 rnDump :: SDoc -> TcRn m ()
1140 -- Dump, with a banner, if -ddump-rn
1141 rnDump doc = dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc)
1143 tcDump :: TcGblEnv -> TcRn m ()
1145 = do { dflags <- getDOpts ;
1147 -- Dump short output if -ddump-types or -ddump-tc
1148 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1149 (dumpTcRn short_dump) ;
1151 -- Dump bindings if -ddump-tc
1152 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1155 short_dump = pprTcGblEnv env
1156 full_dump = ppr (tcg_binds env)
1157 -- NB: foreign x-d's have undefined's in their types;
1158 -- hence can't show the tc_fords
1161 = do { dflags <- getDOpts ;
1162 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1163 (dumpTcRn (pprModGuts mod_guts)) ;
1165 -- Dump bindings if -ddump-tc
1166 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1168 full_dump = pprCoreBindings (mg_binds mod_guts)
1170 -- It's unpleasant having both pprModGuts and pprModDetails here
1171 pprTcGblEnv :: TcGblEnv -> SDoc
1172 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1173 tcg_insts = dfun_ids,
1175 tcg_imports = imports })
1176 = vcat [ ppr_types dfun_ids type_env
1177 , ppr_insts dfun_ids
1178 , vcat (map ppr rules)
1179 , ppr_gen_tycons (typeEnvTyCons type_env)
1180 , ppr (moduleEnvElts (imp_dep_mods imports))
1181 , ppr (imp_dep_pkgs imports)]
1183 pprModGuts :: ModGuts -> SDoc
1184 pprModGuts (ModGuts { mg_types = type_env,
1186 = vcat [ ppr_types [] type_env,
1190 ppr_types :: [Var] -> TypeEnv -> SDoc
1191 ppr_types dfun_ids type_env
1192 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1194 ids = [id | id <- typeEnvIds type_env, want_sig id]
1195 want_sig id | opt_PprStyle_Debug = True
1196 | otherwise = isLocalId id &&
1197 isExternalName (idName id) &&
1198 not (id `elem` dfun_ids)
1199 -- isLocalId ignores data constructors, records selectors etc.
1200 -- The isExternalName ignores local dictionary and method bindings
1201 -- that the type checker has invented. Top-level user-defined things
1202 -- have External names.
1204 ppr_insts :: [Var] -> SDoc
1205 ppr_insts [] = empty
1206 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1208 ppr_sigs :: [Var] -> SDoc
1210 -- Print type signatures
1211 -- Convert to HsType so that we get source-language style printing
1212 -- And sort by RdrName
1213 = vcat $ map ppr_sig $ sortLt lt_sig $
1214 [ (getRdrName id, toHsType (idType id))
1217 lt_sig (n1,_) (n2,_) = n1 < n2
1218 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
1221 ppr_rules :: [IdCoreRule] -> SDoc
1222 ppr_rules [] = empty
1223 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1224 nest 4 (pprIdRules rs),
1227 ppr_gen_tycons [] = empty
1228 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
1229 vcat (map ppr_gen_tycon tcs),
1233 -- x&y are now Id's, not CoreExpr's
1235 | Just ep <- tyConGenInfo tycon
1236 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
1238 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
1241 = vcat [ ptext SLIT("Rep type:") <+> ppr (tcFunResultTy from_tau),
1242 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
1243 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
1246 (_,from_tau) = tcSplitForAllTys (idType from)