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 -- Rename the source decls
662 (tcg_env, rn_src_decls, src_fvs) <- initRn SourceMode (rnSrcDecls group) ;
663 setGblEnv tcg_env $ do {
667 -- Import consquential imports
668 rn_imp_decls <- slurpImpDecls (src_fvs `plusFV` implicitModuleFVs src_fvs) ;
669 let { rn_decls = rn_src_decls `addImpDecls` rn_imp_decls } ;
671 -- Dump trace of renaming part
672 rnDump (ppr rn_decls) ;
673 rnStats rn_imp_decls ;
675 return (tcg_env, rn_decls, src_fvs)
678 ------------------------------------------------
679 tcTopSrcDecls :: HsGroup Name -> TcM TcGblEnv
680 tcTopSrcDecls rn_decls
681 = fixM (\ unf_env -> do {
682 -- Loop back the final environment, including the fully zonked
683 -- versions of bindings from this module. In the presence of mutual
684 -- recursion, interface type signatures may mention variables defined
685 -- in this module, which is why the knot is so big
688 ((tcg_env, binds, rules, fords), lie) <- getLIE (
689 tc_src_decls unf_env rn_decls
692 -- tcSimplifyTop deals with constant or ambiguous InstIds.
693 -- How could there be ambiguous ones? They can only arise if a
694 -- top-level decl falls under the monomorphism
695 -- restriction, and no subsequent decl instantiates its
696 -- type. (Usually, ambiguous type variables are resolved
697 -- during the generalisation step.)
698 traceTc (text "Tc8") ;
699 inst_binds <- setGblEnv tcg_env (tcSimplifyTop lie) ;
700 -- The setGblEnv exposes the instances to tcSimplifyTop
702 -- Backsubstitution. This must be done last.
703 -- Even tcSimplifyTop may do some unification.
704 traceTc (text "Tc9") ;
705 (ids, binds', fords', rules') <- zonkTopDecls (binds `andMonoBinds` inst_binds)
708 let { tcg_env' = tcg_env { tcg_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) ids,
709 tcg_binds = tcg_binds tcg_env `andMonoBinds` binds',
710 tcg_rules = tcg_rules tcg_env ++ rules',
711 tcg_fords = tcg_fords tcg_env ++ fords' } } ;
717 (HsGroup { hs_tyclds = tycl_decls,
718 hs_instds = inst_decls,
719 hs_fords = foreign_decls,
720 hs_defds = default_decls,
721 hs_ruleds = rule_decls,
722 hs_valds = val_binds })
723 = do { -- Type-check the type and class decls, and all imported decls
724 traceTc (text "Tc2") ;
725 tcg_env <- tcTyClDecls unf_env tycl_decls ;
726 setGblEnv tcg_env $ do {
728 -- Source-language instances, including derivings,
729 -- and import the supporting declarations
730 traceTc (text "Tc3") ;
731 (tcg_env, inst_infos, deriv_binds, fvs) <- tcInstDecls1 tycl_decls inst_decls ;
732 setGblEnv tcg_env $ do {
733 tcg_env <- importSupportingDecls fvs ;
734 setGblEnv tcg_env $ do {
736 -- Foreign import declarations next. No zonking necessary
737 -- here; we can tuck them straight into the global environment.
738 traceTc (text "Tc4") ;
739 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
740 tcExtendGlobalValEnv fi_ids $
741 updGblEnv (\gbl -> gbl { tcg_fords = tcg_fords gbl ++ fi_decls })
744 -- Default declarations
745 traceTc (text "Tc4a") ;
746 default_tys <- tcDefaults default_decls ;
747 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
749 -- Value declarations next
750 -- We also typecheck any extra binds that came out
751 -- of the "deriving" process
752 traceTc (text "Tc5") ;
753 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds `ThenBinds` deriv_binds) ;
754 setLclTypeEnv lcl_env $ do {
756 -- Second pass over class and instance declarations,
757 -- plus rules and foreign exports, to generate bindings
758 traceTc (text "Tc6") ;
759 (cls_dm_binds, dm_ids) <- tcClassDecls2 tycl_decls ;
760 tcExtendGlobalValEnv dm_ids $ do {
761 inst_binds <- tcInstDecls2 inst_infos ;
762 showLIE "after instDecls2" ;
765 -- They need to be zonked, so we return them
766 traceTc (text "Tc7") ;
767 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
770 -- Need to partition them because the source rules
771 -- must be zonked before adding them to tcg_rules
772 -- NB: built-in rules come in as IfaceRuleOut's, and
773 -- get added to tcg_rules right here by tcExtendRules
774 rules <- tcRules rule_decls ;
775 let { (src_rules, iface_rules) = partition isSrcRule rules } ;
776 tcExtendRules iface_rules $ do {
779 tcg_env <- getGblEnv ;
780 let { all_binds = tc_val_binds `AndMonoBinds`
781 inst_binds `AndMonoBinds`
782 cls_dm_binds `AndMonoBinds`
785 return (tcg_env, all_binds, src_rules, foe_decls)
790 tcTyClDecls :: RecTcGblEnv
794 -- tcTyClDecls deals with
795 -- type and class decls (some source, some imported)
796 -- interface signatures (checked lazily)
798 -- It returns the TcGblEnv for this module, and side-effects the
799 -- persistent compiler state to reflect the things imported from
802 tcTyClDecls unf_env tycl_decls
803 -- (unf_env :: RecTcGblEnv) is used for type-checking interface pragmas
804 -- which is done lazily [ie failure just drops the pragma
805 -- without having any global-failure effect].
808 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
809 -- an error we'd better stop now, to avoid a cascade
811 traceTc (text "TyCl1") `thenM_`
812 tcTyAndClassDecls tycl_decls `thenM` \ tycl_things ->
813 tcExtendGlobalEnv tycl_things $
815 -- Interface type signatures
816 -- We tie a knot so that the Ids read out of interfaces are in scope
817 -- when we read their pragmas.
818 -- What we rely on is that pragmas are typechecked lazily; if
819 -- any type errors are found (ie there's an inconsistency)
820 -- we silently discard the pragma
821 traceTc (text "TyCl2") `thenM_`
822 tcInterfaceSigs unf_env tycl_decls `thenM` \ sig_ids ->
823 tcExtendGlobalValEnv sig_ids $
825 getGblEnv -- Return the TcLocals environment
830 %************************************************************************
832 Load the old interface file for this module (unless
833 we have it aleady), and check whether it is up to date
836 %************************************************************************
839 checkOldIface :: HscEnv
840 -> PersistentCompilerState
842 -> FilePath -- Where the interface file is
843 -> Bool -- Source unchanged
844 -> Maybe ModIface -- Old interface from compilation manager, if any
845 -> IO (PersistentCompilerState, Maybe (RecompileRequired, Maybe ModIface))
846 -- Nothing <=> errors happened
848 checkOldIface hsc_env pcs mod iface_path source_unchanged maybe_iface
849 = do { showPass (hsc_dflags hsc_env)
850 ("Checking old interface for " ++ moduleUserString mod) ;
852 initTc hsc_env pcs mod
853 (check_old_iface iface_path source_unchanged maybe_iface)
856 check_old_iface iface_path source_unchanged maybe_iface
857 = -- CHECK WHETHER THE SOURCE HAS CHANGED
858 ifM (not source_unchanged)
859 (traceHiDiffs (nest 4 (text "Source file changed or recompilation check turned off")))
862 -- If the source has changed and we're in interactive mode, avoid reading
863 -- an interface; just return the one we might have been supplied with.
864 getGhciMode `thenM` \ ghci_mode ->
865 if (ghci_mode == Interactive) && not source_unchanged then
866 returnM (outOfDate, maybe_iface)
870 Just old_iface -> -- Use the one we already have
871 checkVersions source_unchanged old_iface `thenM` \ recomp ->
872 returnM (recomp, Just old_iface)
874 Nothing -- Try and read it from a file
875 -> getModule `thenM` \ this_mod ->
876 readIface this_mod iface_path False `thenM` \ read_result ->
878 Left err -> -- Old interface file not found, or garbled; give up
880 text "Cannot read old interface file:"
881 $$ nest 4 (text (showException err))) `thenM_`
882 returnM (outOfDate, Nothing)
884 Right parsed_iface ->
885 initRn (InterfaceMode this_mod)
886 (loadOldIface parsed_iface) `thenM` \ m_iface ->
887 checkVersions source_unchanged m_iface `thenM` \ recomp ->
888 returnM (recomp, Just m_iface)
892 %************************************************************************
894 Type-check and rename supporting declarations
895 This is used to deal with the free vars of a splice,
896 or derived code: slurp in the necessary declarations,
897 typecheck them, and add them to the EPS
899 %************************************************************************
902 importSupportingDecls :: FreeVars -> TcM TcGblEnv
903 -- Completely deal with the supporting imports needed
904 -- by the specified free-var set
905 importSupportingDecls fvs
906 = do { traceRn (text "Import supporting decls for" <+> ppr (nameSetToList fvs)) ;
907 decls <- slurpImpDecls fvs ;
908 traceRn (text "...namely:" <+> vcat (map ppr decls)) ;
909 typecheckIfaceDecls (mkGroup decls) }
911 typecheckIfaceDecls :: HsGroup Name -> TcM TcGblEnv
912 -- The decls are all interface-file declarations
913 -- Usually they are all from other modules, but when we are reading
914 -- this module's interface from a file, it's possible that some of
915 -- them are for the module being compiled.
916 -- That is why the tcExtendX functions need to do partitioning.
918 -- If all the decls are from other modules, the returned TcGblEnv
919 -- will have an empty tc_genv, but its tc_inst_env and tc_ist
920 -- caches may have been augmented.
921 typecheckIfaceDecls (HsGroup { hs_tyclds = tycl_decls,
922 hs_instds = inst_decls,
923 hs_ruleds = rule_decls })
924 = do { -- Typecheck the type, class, and interface-sig decls
925 tcg_env <- fixM (\ unf_env -> tcTyClDecls unf_env tycl_decls) ;
926 setGblEnv tcg_env $ do {
928 -- Typecheck the instance decls, and rules
929 -- Note that imported dictionary functions are already
930 -- in scope from the preceding tcTyClDecls
931 tcIfaceInstDecls inst_decls `thenM` \ dfuns ->
932 tcExtendInstEnv dfuns $
933 tcRules rule_decls `thenM` \ rules ->
934 tcExtendRules rules $
936 getGblEnv -- Return the environment
942 %*********************************************************
944 mkGlobalContext: make up an interactive context
946 Used for initialising the lexical environment
947 of the interactive read-eval-print loop
949 %*********************************************************
954 :: HscEnv -> PersistentCompilerState
955 -> [Module] -- Expose these modules' top-level scope
956 -> [Module] -- Expose these modules' exports only
957 -> IO (PersistentCompilerState, Maybe GlobalRdrEnv)
959 mkGlobalContext hsc_env pcs toplevs exports
960 = initTc hsc_env pcs iNTERACTIVE $ do {
962 toplev_envs <- mappM getTopLevScope toplevs ;
963 export_envs <- mappM getModuleExports exports ;
964 returnM (foldr plusGlobalRdrEnv emptyGlobalRdrEnv
965 (toplev_envs ++ export_envs))
968 getTopLevScope :: Module -> TcRn m GlobalRdrEnv
970 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
971 case mi_globals iface of
972 Nothing -> panic "getTopLevScope"
973 Just env -> returnM env }
975 getModuleExports :: Module -> TcRn m GlobalRdrEnv
977 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
978 returnM (foldl add emptyGlobalRdrEnv (mi_exports iface)) }
980 prov_fn n = NonLocalDef ImplicitImport
982 = plusGlobalRdrEnv env (mkGlobalRdrEnv mod True prov_fn avails NoDeprecs)
984 contextDoc = text "context for compiling statements"
990 -> PersistentCompilerState -- IN: persistent compiler state
991 -> Module -- module to inspect
992 -> Bool -- grab just the exports, or the whole toplev
993 -> IO (PersistentCompilerState, Maybe [TyThing])
995 getModuleContents hsc_env pcs mod exports_only
996 = initTc hsc_env pcs iNTERACTIVE $ do {
998 -- Load the interface if necessary (a home module will certainly
999 -- alraedy be loaded, but a package module might not be)
1000 iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
1002 let { export_names = availsToNameSet export_avails ;
1003 export_avails = [ avail | (mn, avails) <- mi_exports iface,
1004 avail <- avails ] } ;
1006 all_names <- if exports_only then
1008 else case mi_globals iface of {
1010 return (get_locals rdr_env) ;
1012 Nothing -> do { addErr (noRdrEnvErr mod) ;
1013 return export_names } } ;
1014 -- Invariant; we only have (not exports_only)
1015 -- for a home module so it must already be in the HIT
1016 -- So the Nothing case is a bug
1018 env <- importSupportingDecls all_names ;
1019 setGblEnv env (mappM tcLookupGlobal (nameSetToList all_names))
1022 -- Grab all the things from the global env that are locally def'd
1023 get_locals rdr_env = mkNameSet [ gre_name gre
1024 | elts <- rdrEnvElts rdr_env,
1027 -- Make a set because a name is often in the envt in
1028 -- both qualified and unqualified forms
1030 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1031 <+> quotes (ppr mod)
1035 %************************************************************************
1039 %************************************************************************
1043 = do { ghci_mode <- getGhciMode ;
1044 tcg_env <- getGblEnv ;
1045 check_main ghci_mode tcg_env
1048 check_main ghci_mode tcg_env
1049 -- If we are in module Main, check that 'main' is defined.
1050 -- It may be imported from another module, in which case
1051 -- we have to drag in its.
1053 -- Also form the definition
1054 -- $main = runIO main
1055 -- so we need to slurp in runIO too.
1057 -- ToDo: We have to return the main_name separately, because it's a
1058 -- bona fide 'use', and should be recorded as such, but the others
1061 -- Blimey: a whole page of code to do this...
1063 | mod_name /= mAIN_Name
1064 = return (tcg_env, emptyFVs)
1066 | not (main_RDR_Unqual `elemRdrEnv` rdr_env)
1067 = do { complain_no_main; return (tcg_env, emptyFVs) }
1070 = do { -- Check that 'main' is in scope
1071 -- It might be imported from another module!
1072 main_name <- lookupSrcName main_RDR_Unqual ;
1075 tcg_env <- importSupportingDecls (unitFV runIOName) ;
1076 setGblEnv tcg_env $ do {
1078 -- $main :: IO () = runIO main
1079 let { rhs = HsApp (HsVar runIOName) (HsVar main_name) } ;
1081 (main_bind, top_lie) <- getLIE (
1082 addSrcLoc (getSrcLoc main_name) $
1083 addErrCtxt mainCtxt $ do {
1084 (main_expr, ty) <- tcExpr_id rhs ;
1085 let { dollar_main_id = setIdLocalExported (mkLocalId dollarMainName ty) } ;
1086 return (VarMonoBind dollar_main_id main_expr)
1089 inst_binds <- tcSimplifyTop top_lie ;
1091 (ids, binds') <- zonkTopBinds (main_bind `andMonoBinds` inst_binds) ;
1093 let { tcg_env' = tcg_env {
1094 tcg_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) ids,
1095 tcg_binds = tcg_binds tcg_env `andMonoBinds` binds' } } ;
1097 return (tcg_env', unitFV main_name)
1100 mod_name = moduleName (tcg_mod tcg_env)
1101 rdr_env = tcg_rdr_env tcg_env
1103 main_RDR_Unqual :: RdrName
1104 main_RDR_Unqual = mkUnqual varName FSLIT("main")
1105 -- Don't get a RdrName from PrelNames.mainName, because
1106 -- nameRdrNamegets an Orig RdrName, and we want a Qual or Unqual one.
1107 -- An Unqual one will do just fine
1109 complain_no_main | ghci_mode == Interactive = return ()
1110 | otherwise = addErr noMainMsg
1111 -- In interactive mode, don't worry about the absence of 'main'
1113 mainCtxt = ptext SLIT("When checking the type of 'main'")
1114 noMainMsg = ptext SLIT("No 'main' defined in module Main")
1118 %************************************************************************
1122 %************************************************************************
1125 rnDump :: SDoc -> TcRn m ()
1126 -- Dump, with a banner, if -ddump-rn
1127 rnDump doc = dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc)
1129 tcDump :: TcGblEnv -> TcRn m ()
1131 = do { dflags <- getDOpts ;
1133 -- Dump short output if -ddump-types or -ddump-tc
1134 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1135 (dumpTcRn short_dump) ;
1137 -- Dump bindings if -ddump-tc
1138 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1141 short_dump = pprTcGblEnv env
1142 full_dump = ppr (tcg_binds env)
1143 -- NB: foreign x-d's have undefined's in their types;
1144 -- hence can't show the tc_fords
1147 = do { dflags <- getDOpts ;
1148 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1149 (dumpTcRn (pprModGuts mod_guts)) ;
1151 -- Dump bindings if -ddump-tc
1152 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1154 full_dump = pprCoreBindings (mg_binds mod_guts)
1156 -- It's unpleasant having both pprModGuts and pprModDetails here
1157 pprTcGblEnv :: TcGblEnv -> SDoc
1158 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1159 tcg_insts = dfun_ids,
1160 tcg_rules = rules })
1161 = vcat [ ppr_types dfun_ids type_env
1162 , ppr_insts dfun_ids
1163 , vcat (map ppr rules)
1164 , ppr_gen_tycons (typeEnvTyCons type_env)]
1166 pprModGuts :: ModGuts -> SDoc
1167 pprModGuts (ModGuts { mg_types = type_env,
1169 = vcat [ ppr_types [] type_env,
1173 ppr_types :: [Var] -> TypeEnv -> SDoc
1174 ppr_types dfun_ids type_env
1175 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1177 ids = [id | id <- typeEnvIds type_env, want_sig id]
1178 want_sig id | opt_PprStyle_Debug = True
1179 | otherwise = isLocalId id &&
1180 isExternalName (idName id) &&
1181 not (id `elem` dfun_ids)
1182 -- isLocalId ignores data constructors, records selectors etc.
1183 -- The isExternalName ignores local dictionary and method bindings
1184 -- that the type checker has invented. Top-level user-defined things
1185 -- have External names.
1187 ppr_insts :: [Var] -> SDoc
1188 ppr_insts [] = empty
1189 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1191 ppr_sigs :: [Var] -> SDoc
1193 -- Print type signatures
1194 -- Convert to HsType so that we get source-language style printing
1195 -- And sort by RdrName
1196 = vcat $ map ppr_sig $ sortLt lt_sig $
1197 [ (getRdrName id, toHsType (idType id))
1200 lt_sig (n1,_) (n2,_) = n1 < n2
1201 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
1204 ppr_rules :: [IdCoreRule] -> SDoc
1205 ppr_rules [] = empty
1206 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1207 nest 4 (pprIdRules rs),
1210 ppr_gen_tycons [] = empty
1211 ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
1212 vcat (map ppr_gen_tycon tcs),
1216 -- x&y are now Id's, not CoreExpr's
1218 | Just ep <- tyConGenInfo tycon
1219 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
1221 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
1224 = vcat [ ptext SLIT("Rep type:") <+> ppr (tcFunResultTy from_tau),
1225 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
1226 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
1229 (_,from_tau) = tcSplitForAllTys (idType from)