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, mkUnqual, 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 ( RecTcGblEnv,
63 tcExtendInstEnv, tcExtendRules,
64 tcLookupTyCon, tcLookupGlobal,
67 import TcRules ( tcRules )
68 import TcForeign ( tcForeignImports, tcForeignExports )
69 import TcIfaceSig ( tcInterfaceSigs, tcCoreBinds )
70 import TcInstDcls ( tcInstDecls1, tcIfaceInstDecls, tcInstDecls2 )
71 import TcSimplify ( tcSimplifyTop, tcSimplifyInfer )
72 import TcTyClsDecls ( tcTyAndClassDecls )
74 import RnNames ( rnImports, exportsFromAvail, reportUnusedNames )
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 RnNames ( importsFromLocalDecls )
81 import RnSource ( rnSrcDecls, checkModDeprec, rnStats )
83 import OccName ( varName )
84 import CoreUnfold ( unfoldingTemplate )
85 import CoreSyn ( IdCoreRule, Bind(..) )
86 import PprCore ( pprIdRules, pprCoreBindings )
87 import TysWiredIn ( mkListTy, unitTy )
88 import ErrUtils ( mkDumpDoc, showPass )
89 import Id ( Id, mkLocalId, isLocalId, idName, idType, idUnfolding, setIdLocalExported )
90 import IdInfo ( GlobalIdDetails(..) )
91 import Var ( Var, setGlobalIdDetails )
92 import Module ( Module, moduleName, moduleUserString, moduleEnvElts )
93 import Name ( Name, isExternalName, getSrcLoc, nameOccName )
94 import NameEnv ( delListFromNameEnv )
96 import TyCon ( tyConGenInfo )
97 import BasicTypes ( EP(..), RecFlag(..) )
98 import SrcLoc ( noSrcLoc )
100 import HscTypes ( PersistentCompilerState(..), InteractiveContext(..),
101 ModIface, ModDetails(..), ModGuts(..),
103 ModIface(..), ModDetails(..), IfaceDecls(..),
104 GhciMode(..), noDependencies,
105 Deprecations(..), plusDeprecs,
107 GenAvailInfo(Avail), availsToNameSet,
109 TypeEnv, TyThing, typeEnvTyCons,
110 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
111 extendLocalRdrEnv, emptyFixityEnv
114 import RdrName ( rdrEnvElts )
115 import RnHiFiles ( loadInterface )
116 import RnEnv ( mkGlobalRdrEnv )
117 import HscTypes ( GlobalRdrElt(..), GlobalRdrEnv, ImportReason(..), Provenance(..),
121 import Maybe ( catMaybes )
122 import Panic ( showException )
123 import List ( partition )
124 import Util ( sortLt )
129 %************************************************************************
131 Typecheck and rename a module
133 %************************************************************************
137 tcRnModule :: HscEnv -> PersistentCompilerState
139 -> IO (PersistentCompilerState, Maybe TcGblEnv)
141 tcRnModule hsc_env pcs
142 (HsModule this_mod _ exports import_decls local_decls mod_deprec loc)
143 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
145 initTc hsc_env pcs this_mod $ addSrcLoc loc $
146 do { -- Deal with imports; sets tcg_rdr_env, tcg_imports
147 (rdr_env, imports) <- rnImports import_decls ;
148 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
149 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
151 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
152 -- Fail if there are any errors so far
153 -- The error printing (if needed) takes advantage
154 -- of the tcg_env we have now set
157 traceRn (text "rn1a") ;
158 -- Rename and type check the declarations
159 (tcg_env, src_fvs) <- tcRnSrcDecls local_decls ;
160 setGblEnv tcg_env $ do {
161 traceRn (text "rn2") ;
164 (tcg_env, main_fvs) <- checkMain ;
165 setGblEnv tcg_env $ do {
167 traceRn (text "rn3") ;
168 -- Check whether the entire module is deprecated
169 -- This happens only once per module
170 -- Returns the full new deprecations; a module deprecation
171 -- over-rides the earlier ones
172 let { mod_deprecs = checkModDeprec mod_deprec } ;
173 updGblEnv (\gbl -> gbl { tcg_deprecs = tcg_deprecs gbl `plusDeprecs` mod_deprecs })
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 -- 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
598 tcRnSrcDecls [] = do { tcg_env <- getGblEnv ; return (tcg_env, emptyFVs) }
600 = do { let { (first_group, group_tail) = findSplice ds } ;
602 -- Type check the decls up to, but not including, the first splice
603 (tcg_env, src_fvs1) <- tcRnGroup first_group ;
605 -- If there is no splice, we're done
607 Nothing -> return (tcg_env, src_fvs1)
608 Just (SpliceDecl splice_expr splice_loc, rest_ds) -> do {
610 setGblEnv tcg_env $ do {
613 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
615 -- Rename the splice expression, and get its supporting decls
616 (rn_splice_expr, fvs) <- initRn SourceMode $
617 addSrcLoc splice_loc $
619 tcg_env <- importSupportingDecls (fvs `plusFV` templateHaskellNames) ;
620 setGblEnv tcg_env $ do {
622 -- Execute the splice
623 spliced_decls <- tcSpliceDecls rn_splice_expr ;
625 -- Glue them on the front of the remaining decls and loop
626 (tcg_env, src_fvs2) <- tcRnSrcDecls (spliced_decls ++ rest_ds) ;
628 return (tcg_env, src_fvs1 `plusFV` src_fvs2)
635 %************************************************************************
637 Type-checking the top level of a module
639 %************************************************************************
641 tcRnGroup takes a bunch of top-level source-code declarations, and
643 * gets supporting declarations from interface files
646 * and augments the TcGblEnv with the results
648 In Template Haskell it may be called repeatedly for each group of
649 declarations. It expects there to be an incoming TcGblEnv in the
650 monad; it augments it and returns the new TcGblEnv.
653 tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, FreeVars)
654 -- Returns the variables free in the decls
656 = do { -- Rename the declarations
657 (tcg_env, rn_decls, src_fvs) <- rnTopSrcDecls decls ;
658 setGblEnv tcg_env $ do {
660 -- Typecheck the declarations
661 tcg_env <- tcTopSrcDecls rn_decls ;
662 return (tcg_env, src_fvs)
665 ------------------------------------------------
666 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name, FreeVars)
668 = do { -- Bring top level binders into scope
669 (rdr_env, imports) <- importsFromLocalDecls group ;
670 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv`
672 tcg_imports = imports `plusImportAvails`
676 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
678 -- Rename the source decls
679 (tcg_env, rn_src_decls, src_fvs) <- initRn SourceMode (rnSrcDecls group) ;
680 setGblEnv tcg_env $ do {
684 -- Import consquential imports
685 rn_imp_decls <- slurpImpDecls (src_fvs `plusFV` implicitModuleFVs src_fvs) ;
686 let { rn_decls = rn_src_decls `addImpDecls` rn_imp_decls } ;
688 -- Dump trace of renaming part
689 rnDump (ppr rn_decls) ;
690 rnStats rn_imp_decls ;
692 return (tcg_env, rn_decls, src_fvs)
695 ------------------------------------------------
696 tcTopSrcDecls :: HsGroup Name -> TcM TcGblEnv
697 tcTopSrcDecls rn_decls
698 = fixM (\ unf_env -> do {
699 -- Loop back the final environment, including the fully zonked
700 -- versions of bindings from this module. In the presence of mutual
701 -- recursion, interface type signatures may mention variables defined
702 -- in this module, which is why the knot is so big
705 ((tcg_env, lcl_env, binds, rules, fords), lie) <- getLIE (
706 tc_src_decls unf_env rn_decls
709 -- tcSimplifyTop deals with constant or ambiguous InstIds.
710 -- How could there be ambiguous ones? They can only arise if a
711 -- top-level decl falls under the monomorphism
712 -- restriction, and no subsequent decl instantiates its
713 -- type. (Usually, ambiguous type variables are resolved
714 -- during the generalisation step.)
715 traceTc (text "Tc8") ;
716 inst_binds <- setGblEnv tcg_env $
717 setLclTypeEnv lcl_env $
719 -- The setGblEnv exposes the instances to tcSimplifyTop
720 -- The steLclTypeEnv exposes the local Ids, so that
721 -- we get better error messages (monomorphism restriction)
723 -- Backsubstitution. This must be done last.
724 -- Even tcSimplifyTop may do some unification.
725 traceTc (text "Tc9") ;
726 (ids, binds', fords', rules') <- zonkTopDecls (binds `andMonoBinds` inst_binds)
729 let { tcg_env' = tcg_env { tcg_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) ids,
730 tcg_binds = tcg_binds tcg_env `andMonoBinds` binds',
731 tcg_rules = tcg_rules tcg_env ++ rules',
732 tcg_fords = tcg_fords tcg_env ++ fords' } } ;
738 (HsGroup { hs_tyclds = tycl_decls,
739 hs_instds = inst_decls,
740 hs_fords = foreign_decls,
741 hs_defds = default_decls,
742 hs_ruleds = rule_decls,
743 hs_valds = val_binds })
744 = do { -- Type-check the type and class decls, and all imported decls
745 traceTc (text "Tc2") ;
746 tcg_env <- tcTyClDecls unf_env tycl_decls ;
747 setGblEnv tcg_env $ do {
749 -- Source-language instances, including derivings,
750 -- and import the supporting declarations
751 traceTc (text "Tc3") ;
752 (tcg_env, inst_infos, deriv_binds, fvs) <- tcInstDecls1 tycl_decls inst_decls ;
753 setGblEnv tcg_env $ do {
754 tcg_env <- importSupportingDecls fvs ;
755 setGblEnv tcg_env $ do {
757 -- Foreign import declarations next. No zonking necessary
758 -- here; we can tuck them straight into the global environment.
759 traceTc (text "Tc4") ;
760 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
761 tcExtendGlobalValEnv fi_ids $
762 updGblEnv (\gbl -> gbl { tcg_fords = tcg_fords gbl ++ fi_decls })
765 -- Default declarations
766 traceTc (text "Tc4a") ;
767 default_tys <- tcDefaults default_decls ;
768 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
770 -- Value declarations next
771 -- We also typecheck any extra binds that came out
772 -- of the "deriving" process
773 traceTc (text "Tc5") ;
774 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds `ThenBinds` deriv_binds) ;
775 setLclTypeEnv lcl_env $ do {
777 -- Second pass over class and instance declarations,
778 -- plus rules and foreign exports, to generate bindings
779 traceTc (text "Tc6") ;
780 (cls_dm_binds, dm_ids) <- tcClassDecls2 tycl_decls ;
781 tcExtendGlobalValEnv dm_ids $ do {
782 inst_binds <- tcInstDecls2 inst_infos ;
783 showLIE "after instDecls2" ;
786 -- They need to be zonked, so we return them
787 traceTc (text "Tc7") ;
788 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
791 -- Need to partition them because the source rules
792 -- must be zonked before adding them to tcg_rules
793 -- NB: built-in rules come in as IfaceRuleOut's, and
794 -- get added to tcg_rules right here by tcExtendRules
795 rules <- tcRules rule_decls ;
796 let { (src_rules, iface_rules) = partition isSrcRule rules } ;
797 tcExtendRules iface_rules $ do {
800 tcg_env <- getGblEnv ;
801 let { all_binds = tc_val_binds `AndMonoBinds`
802 inst_binds `AndMonoBinds`
803 cls_dm_binds `AndMonoBinds`
806 return (tcg_env, lcl_env, all_binds, src_rules, foe_decls)
811 tcTyClDecls :: RecTcGblEnv
815 -- tcTyClDecls deals with
816 -- type and class decls (some source, some imported)
817 -- interface signatures (checked lazily)
819 -- It returns the TcGblEnv for this module, and side-effects the
820 -- persistent compiler state to reflect the things imported from
823 tcTyClDecls unf_env tycl_decls
824 -- (unf_env :: RecTcGblEnv) is used for type-checking interface pragmas
825 -- which is done lazily [ie failure just drops the pragma
826 -- without having any global-failure effect].
829 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
830 -- an error we'd better stop now, to avoid a cascade
832 traceTc (text "TyCl1") `thenM_`
833 tcTyAndClassDecls tycl_decls `thenM` \ tycl_things ->
834 tcExtendGlobalEnv tycl_things $
836 -- Interface type signatures
837 -- We tie a knot so that the Ids read out of interfaces are in scope
838 -- when we read their pragmas.
839 -- What we rely on is that pragmas are typechecked lazily; if
840 -- any type errors are found (ie there's an inconsistency)
841 -- we silently discard the pragma
842 traceTc (text "TyCl2") `thenM_`
843 tcInterfaceSigs unf_env tycl_decls `thenM` \ sig_ids ->
844 tcExtendGlobalValEnv sig_ids $
846 getGblEnv -- Return the TcLocals environment
851 %************************************************************************
853 Load the old interface file for this module (unless
854 we have it aleady), and check whether it is up to date
857 %************************************************************************
860 checkOldIface :: HscEnv
861 -> PersistentCompilerState
863 -> FilePath -- Where the interface file is
864 -> Bool -- Source unchanged
865 -> Maybe ModIface -- Old interface from compilation manager, if any
866 -> IO (PersistentCompilerState, Maybe (RecompileRequired, Maybe ModIface))
867 -- Nothing <=> errors happened
869 checkOldIface hsc_env pcs mod iface_path source_unchanged maybe_iface
870 = do { showPass (hsc_dflags hsc_env)
871 ("Checking old interface for " ++ moduleUserString mod) ;
873 initTc hsc_env pcs mod
874 (check_old_iface iface_path source_unchanged maybe_iface)
877 check_old_iface iface_path source_unchanged maybe_iface
878 = -- CHECK WHETHER THE SOURCE HAS CHANGED
879 ifM (not source_unchanged)
880 (traceHiDiffs (nest 4 (text "Source file changed or recompilation check turned off")))
883 -- If the source has changed and we're in interactive mode, avoid reading
884 -- an interface; just return the one we might have been supplied with.
885 getGhciMode `thenM` \ ghci_mode ->
886 if (ghci_mode == Interactive) && not source_unchanged then
887 returnM (outOfDate, maybe_iface)
891 Just old_iface -> -- Use the one we already have
892 checkVersions source_unchanged old_iface `thenM` \ recomp ->
893 returnM (recomp, Just old_iface)
895 Nothing -- Try and read it from a file
896 -> getModule `thenM` \ this_mod ->
897 readIface this_mod iface_path False `thenM` \ read_result ->
899 Left err -> -- Old interface file not found, or garbled; give up
901 text "Cannot read old interface file:"
902 $$ nest 4 (text (showException err))) `thenM_`
903 returnM (outOfDate, Nothing)
905 Right parsed_iface ->
906 initRn (InterfaceMode this_mod)
907 (loadOldIface parsed_iface) `thenM` \ m_iface ->
908 checkVersions source_unchanged m_iface `thenM` \ recomp ->
909 returnM (recomp, Just m_iface)
913 %************************************************************************
915 Type-check and rename supporting declarations
916 This is used to deal with the free vars of a splice,
917 or derived code: slurp in the necessary declarations,
918 typecheck them, and add them to the EPS
920 %************************************************************************
923 importSupportingDecls :: FreeVars -> TcM TcGblEnv
924 -- Completely deal with the supporting imports needed
925 -- by the specified free-var set
926 importSupportingDecls fvs
927 = do { traceRn (text "Import supporting decls for" <+> ppr (nameSetToList fvs)) ;
928 decls <- slurpImpDecls fvs ;
929 traceRn (text "...namely:" <+> vcat (map ppr decls)) ;
930 typecheckIfaceDecls (mkGroup decls) }
932 typecheckIfaceDecls :: HsGroup Name -> TcM TcGblEnv
933 -- The decls are all interface-file declarations
934 -- Usually they are all from other modules, but when we are reading
935 -- this module's interface from a file, it's possible that some of
936 -- them are for the module being compiled.
937 -- That is why the tcExtendX functions need to do partitioning.
939 -- If all the decls are from other modules, the returned TcGblEnv
940 -- will have an empty tc_genv, but its tc_inst_env and tc_ist
941 -- caches may have been augmented.
942 typecheckIfaceDecls (HsGroup { hs_tyclds = tycl_decls,
943 hs_instds = inst_decls,
944 hs_ruleds = rule_decls })
945 = do { -- Typecheck the type, class, and interface-sig decls
946 tcg_env <- fixM (\ unf_env -> tcTyClDecls unf_env tycl_decls) ;
947 setGblEnv tcg_env $ do {
949 -- Typecheck the instance decls, and rules
950 -- Note that imported dictionary functions are already
951 -- in scope from the preceding tcTyClDecls
952 tcIfaceInstDecls inst_decls `thenM` \ dfuns ->
953 tcExtendInstEnv dfuns $
954 tcRules rule_decls `thenM` \ rules ->
955 tcExtendRules rules $
957 getGblEnv -- Return the environment
963 %*********************************************************
965 mkGlobalContext: make up an interactive context
967 Used for initialising the lexical environment
968 of the interactive read-eval-print loop
970 %*********************************************************
975 :: HscEnv -> PersistentCompilerState
976 -> [Module] -- Expose these modules' top-level scope
977 -> [Module] -- Expose these modules' exports only
978 -> IO (PersistentCompilerState, Maybe GlobalRdrEnv)
980 mkGlobalContext hsc_env pcs toplevs exports
981 = initTc hsc_env pcs iNTERACTIVE $ do {
983 toplev_envs <- mappM getTopLevScope toplevs ;
984 export_envs <- mappM getModuleExports exports ;
985 returnM (foldr plusGlobalRdrEnv emptyGlobalRdrEnv
986 (toplev_envs ++ export_envs))
989 getTopLevScope :: Module -> TcRn m GlobalRdrEnv
991 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
992 case mi_globals iface of
993 Nothing -> panic "getTopLevScope"
994 Just env -> returnM env }
996 getModuleExports :: Module -> TcRn m GlobalRdrEnv
998 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
999 returnM (foldl add emptyGlobalRdrEnv (mi_exports iface)) }
1001 prov_fn n = NonLocalDef ImplicitImport
1002 add env (mod,avails)
1003 = plusGlobalRdrEnv env (mkGlobalRdrEnv mod True prov_fn avails NoDeprecs)
1005 contextDoc = text "context for compiling statements"
1011 -> PersistentCompilerState -- IN: persistent compiler state
1012 -> Module -- module to inspect
1013 -> Bool -- grab just the exports, or the whole toplev
1014 -> IO (PersistentCompilerState, Maybe [TyThing])
1016 getModuleContents hsc_env pcs mod exports_only
1017 = initTc hsc_env pcs iNTERACTIVE $ do {
1019 -- Load the interface if necessary (a home module will certainly
1020 -- alraedy be loaded, but a package module might not be)
1021 iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
1023 let { export_names = availsToNameSet export_avails ;
1024 export_avails = [ avail | (mn, avails) <- mi_exports iface,
1025 avail <- avails ] } ;
1027 all_names <- if exports_only then
1029 else case mi_globals iface of {
1031 return (get_locals rdr_env) ;
1033 Nothing -> do { addErr (noRdrEnvErr mod) ;
1034 return export_names } } ;
1035 -- Invariant; we only have (not exports_only)
1036 -- for a home module so it must already be in the HIT
1037 -- So the Nothing case is a bug
1039 env <- importSupportingDecls all_names ;
1040 setGblEnv env (mappM tcLookupGlobal (nameSetToList all_names))
1043 -- Grab all the things from the global env that are locally def'd
1044 get_locals rdr_env = mkNameSet [ gre_name gre
1045 | elts <- rdrEnvElts rdr_env,
1048 -- Make a set because a name is often in the envt in
1049 -- both qualified and unqualified forms
1051 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1052 <+> quotes (ppr mod)
1056 %************************************************************************
1060 %************************************************************************
1064 = do { ghci_mode <- getGhciMode ;
1065 tcg_env <- getGblEnv ;
1066 check_main ghci_mode tcg_env
1069 check_main ghci_mode tcg_env
1070 -- If we are in module Main, check that 'main' is defined.
1071 -- It may be imported from another module, in which case
1072 -- we have to drag in its.
1074 -- Also form the definition
1075 -- $main = runIO main
1076 -- so we need to slurp in runIO too.
1078 -- ToDo: We have to return the main_name separately, because it's a
1079 -- bona fide 'use', and should be recorded as such, but the others
1082 -- Blimey: a whole page of code to do this...
1084 | mod_name /= mAIN_Name
1085 = return (tcg_env, emptyFVs)
1087 | not (main_RDR_Unqual `elemRdrEnv` rdr_env)
1088 = do { complain_no_main; return (tcg_env, emptyFVs) }
1091 = do { -- Check that 'main' is in scope
1092 -- It might be imported from another module!
1093 main_name <- lookupSrcName main_RDR_Unqual ;
1096 tcg_env <- importSupportingDecls (unitFV runIOName) ;
1097 setGblEnv tcg_env $ do {
1099 -- $main :: IO () = runIO main
1100 let { rhs = HsApp (HsVar runIOName) (HsVar main_name) } ;
1102 (main_bind, top_lie) <- getLIE (
1103 addSrcLoc (getSrcLoc main_name) $
1104 addErrCtxt mainCtxt $ do {
1105 (main_expr, ty) <- tcExpr_id rhs ;
1106 let { dollar_main_id = setIdLocalExported (mkLocalId dollarMainName ty) } ;
1107 return (VarMonoBind dollar_main_id main_expr)
1110 inst_binds <- tcSimplifyTop top_lie ;
1112 (ids, binds') <- zonkTopBinds (main_bind `andMonoBinds` inst_binds) ;
1114 let { tcg_env' = tcg_env {
1115 tcg_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) ids,
1116 tcg_binds = tcg_binds tcg_env `andMonoBinds` binds' } } ;
1118 return (tcg_env', unitFV main_name)
1121 mod_name = moduleName (tcg_mod tcg_env)
1122 rdr_env = tcg_rdr_env tcg_env
1124 main_RDR_Unqual :: RdrName
1125 main_RDR_Unqual = mkUnqual varName FSLIT("main")
1126 -- Don't get a RdrName from PrelNames.mainName, because
1127 -- nameRdrNamegets an Orig RdrName, and we want a Qual or Unqual one.
1128 -- An Unqual one will do just fine
1130 complain_no_main | ghci_mode == Interactive = return ()
1131 | otherwise = addErr noMainMsg
1132 -- In interactive mode, don't worry about the absence of 'main'
1134 mainCtxt = ptext SLIT("When checking the type of 'main'")
1135 noMainMsg = ptext SLIT("No 'main' defined in module Main")
1139 %************************************************************************
1143 %************************************************************************
1146 rnDump :: SDoc -> TcRn m ()
1147 -- Dump, with a banner, if -ddump-rn
1148 rnDump doc = dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc)
1150 tcDump :: TcGblEnv -> TcRn m ()
1152 = do { dflags <- getDOpts ;
1154 -- Dump short output if -ddump-types or -ddump-tc
1155 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1156 (dumpTcRn short_dump) ;
1158 -- Dump bindings if -ddump-tc
1159 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1162 short_dump = pprTcGblEnv env
1163 full_dump = ppr (tcg_binds env)
1164 -- NB: foreign x-d's have undefined's in their types;
1165 -- hence can't show the tc_fords
1168 = do { dflags <- getDOpts ;
1169 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1170 (dumpTcRn (pprModGuts mod_guts)) ;
1172 -- Dump bindings if -ddump-tc
1173 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1175 full_dump = pprCoreBindings (mg_binds mod_guts)
1177 -- It's unpleasant having both pprModGuts and pprModDetails here
1178 pprTcGblEnv :: TcGblEnv -> SDoc
1179 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1180 tcg_insts = dfun_ids,
1182 tcg_imports = imports })
1183 = vcat [ ppr_types dfun_ids type_env
1184 , ppr_insts dfun_ids
1185 , vcat (map ppr rules)
1186 , ppr_gen_tycons (typeEnvTyCons type_env)
1187 , ppr (moduleEnvElts (imp_dep_mods imports))
1188 , ppr (imp_dep_pkgs imports)]
1190 pprModGuts :: ModGuts -> SDoc
1191 pprModGuts (ModGuts { mg_types = type_env,
1193 = vcat [ ppr_types [] type_env,
1197 ppr_types :: [Var] -> TypeEnv -> SDoc
1198 ppr_types dfun_ids type_env
1199 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1201 ids = [id | id <- typeEnvIds type_env, want_sig id]
1202 want_sig id | opt_PprStyle_Debug = True
1203 | otherwise = isLocalId id &&
1204 isExternalName (idName id) &&
1205 not (id `elem` dfun_ids)
1206 -- isLocalId ignores data constructors, records selectors etc.
1207 -- The isExternalName ignores local dictionary and method bindings
1208 -- that the type checker has invented. Top-level user-defined things
1209 -- have External names.
1211 ppr_insts :: [Var] -> SDoc
1212 ppr_insts [] = empty
1213 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1215 ppr_sigs :: [Var] -> SDoc
1217 -- Print type signatures
1218 -- Convert to HsType so that we get source-language style printing
1219 -- And sort by RdrName
1220 = vcat $ map ppr_sig $ sortLt lt_sig $
1221 [ (getRdrName id, toHsType (idType id))
1224 lt_sig (n1,_) (n2,_) = n1 < n2
1225 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
1228 ppr_rules :: [IdCoreRule] -> SDoc
1229 ppr_rules [] = empty
1230 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1231 nest 4 (pprIdRules rs),
1234 ppr_gen_tycons [] = empty
1235 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
1236 vcat (map ppr_gen_tycon tcs),
1240 -- x&y are now Id's, not CoreExpr's
1242 | Just ep <- tyConGenInfo tycon
1243 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
1245 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
1248 = vcat [ ptext SLIT("Rep type:") <+> ppr (tcFunResultTy from_tau),
1249 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
1250 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
1253 (_,from_tau) = tcSplitForAllTys (idType from)