2 % (c) The University of Glasgow 2006
12 #include "HsVersions.h"
14 import TcRnTypes -- Re-export all
15 import IOEnv -- Re-export all
17 import HsSyn hiding (LIE)
25 import PrelNames ( iNTERACTIVE )
48 import qualified Data.Set as Set
54 %************************************************************************
58 %************************************************************************
64 -> Bool -- True <=> retain renamed syntax trees
67 -> IO (Messages, Maybe r)
68 -- Nothing => error thrown by the thing inside
69 -- (error messages should have been printed already)
71 initTc hsc_env hsc_src keep_rn_syntax mod do_this
72 = do { errs_var <- newIORef (emptyBag, emptyBag) ;
73 meta_var <- newIORef initTyVarUnique ;
74 tvs_var <- newIORef emptyVarSet ;
75 keep_var <- newIORef emptyNameSet ;
76 used_rdr_var <- newIORef Set.empty ;
77 th_var <- newIORef False ;
78 lie_var <- newIORef emptyWC ;
79 dfun_n_var <- newIORef emptyOccSet ;
80 type_env_var <- case hsc_type_env_var hsc_env of {
81 Just (_mod, te_var) -> return te_var ;
82 Nothing -> newIORef emptyNameEnv } ;
84 maybe_rn_syntax :: forall a. a -> Maybe a ;
85 maybe_rn_syntax empty_val
86 | keep_rn_syntax = Just empty_val
87 | otherwise = Nothing ;
92 tcg_rdr_env = emptyGlobalRdrEnv,
93 tcg_fix_env = emptyNameEnv,
94 tcg_field_env = RecFields emptyNameEnv emptyNameSet,
95 tcg_default = Nothing,
96 tcg_type_env = emptyNameEnv,
97 tcg_type_env_var = type_env_var,
98 tcg_inst_env = emptyInstEnv,
99 tcg_fam_inst_env = emptyFamInstEnv,
100 tcg_th_used = th_var,
102 tcg_imports = emptyImportAvails,
103 tcg_used_rdrnames = used_rdr_var,
107 tcg_rn_exports = maybe_rn_syntax [],
108 tcg_rn_decls = maybe_rn_syntax emptyRnGroup,
110 tcg_binds = emptyLHsBinds,
112 tcg_sigs = emptyNameSet,
113 tcg_ev_binds = emptyBag,
114 tcg_warns = NoWarnings,
121 tcg_dfun_n = dfun_n_var,
123 tcg_doc_hdr = Nothing,
129 tcl_loc = mkGeneralSrcSpan (fsLit "Top level"),
131 tcl_rdr = emptyLocalRdrEnv,
132 tcl_th_ctxt = topStage,
133 tcl_arrow_ctxt = NoArrowCtxt,
134 tcl_env = emptyNameEnv,
135 tcl_tyvars = tvs_var,
138 tcl_untch = initTyVarUnique
142 -- OK, here's the business end!
143 maybe_res <- initTcRnIf 'a' hsc_env gbl_env lcl_env $
144 do { r <- tryM do_this
146 Right res -> return (Just res)
147 Left _ -> return Nothing } ;
149 -- Check for unsolved constraints
150 lie <- readIORef lie_var ;
153 else pprPanic "initTc: unsolved constraints"
154 (pprWantedsWithLocs lie) ;
156 -- Collect any error messages
157 msgs <- readIORef errs_var ;
159 let { dflags = hsc_dflags hsc_env
160 ; final_res | errorsFound dflags msgs = Nothing
161 | otherwise = maybe_res } ;
163 return (msgs, final_res)
166 initTcPrintErrors -- Used from the interactive loop only
170 -> IO (Messages, Maybe r)
172 initTcPrintErrors env mod todo = initTc env HsSrcFile False mod todo
175 %************************************************************************
179 %************************************************************************
183 initTcRnIf :: Char -- Tag for unique supply
188 initTcRnIf uniq_tag hsc_env gbl_env lcl_env thing_inside
189 = do { us <- mkSplitUniqSupply uniq_tag ;
190 ; us_var <- newIORef us ;
192 ; let { env = Env { env_top = hsc_env,
197 ; runIOEnv env thing_inside
201 %************************************************************************
205 %************************************************************************
208 getTopEnv :: TcRnIf gbl lcl HscEnv
209 getTopEnv = do { env <- getEnv; return (env_top env) }
211 getGblEnv :: TcRnIf gbl lcl gbl
212 getGblEnv = do { env <- getEnv; return (env_gbl env) }
214 updGblEnv :: (gbl -> gbl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
215 updGblEnv upd = updEnv (\ env@(Env { env_gbl = gbl }) ->
216 env { env_gbl = upd gbl })
218 setGblEnv :: gbl -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
219 setGblEnv gbl_env = updEnv (\ env -> env { env_gbl = gbl_env })
221 getLclEnv :: TcRnIf gbl lcl lcl
222 getLclEnv = do { env <- getEnv; return (env_lcl env) }
224 updLclEnv :: (lcl -> lcl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
225 updLclEnv upd = updEnv (\ env@(Env { env_lcl = lcl }) ->
226 env { env_lcl = upd lcl })
228 setLclEnv :: lcl' -> TcRnIf gbl lcl' a -> TcRnIf gbl lcl a
229 setLclEnv lcl_env = updEnv (\ env -> env { env_lcl = lcl_env })
231 getEnvs :: TcRnIf gbl lcl (gbl, lcl)
232 getEnvs = do { env <- getEnv; return (env_gbl env, env_lcl env) }
234 setEnvs :: (gbl', lcl') -> TcRnIf gbl' lcl' a -> TcRnIf gbl lcl a
235 setEnvs (gbl_env, lcl_env) = updEnv (\ env -> env { env_gbl = gbl_env, env_lcl = lcl_env })
242 getDOpts :: TcRnIf gbl lcl DynFlags
243 getDOpts = do { env <- getTopEnv; return (hsc_dflags env) }
245 xoptM :: ExtensionFlag -> TcRnIf gbl lcl Bool
246 xoptM flag = do { dflags <- getDOpts; return (xopt flag dflags) }
248 doptM :: DynFlag -> TcRnIf gbl lcl Bool
249 doptM flag = do { dflags <- getDOpts; return (dopt flag dflags) }
251 -- XXX setOptM and unsetOptM operate on different types. One should be renamed.
253 setOptM :: ExtensionFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
254 setOptM flag = updEnv (\ env@(Env { env_top = top }) ->
255 env { env_top = top { hsc_dflags = xopt_set (hsc_dflags top) flag}} )
257 unsetOptM :: DynFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
258 unsetOptM flag = updEnv (\ env@(Env { env_top = top }) ->
259 env { env_top = top { hsc_dflags = dopt_unset (hsc_dflags top) flag}} )
261 -- | Do it flag is true
262 ifDOptM :: DynFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl ()
263 ifDOptM flag thing_inside = do { b <- doptM flag;
264 if b then thing_inside else return () }
266 ifXOptM :: ExtensionFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl ()
267 ifXOptM flag thing_inside = do { b <- xoptM flag;
268 if b then thing_inside else return () }
270 getGhcMode :: TcRnIf gbl lcl GhcMode
271 getGhcMode = do { env <- getTopEnv; return (ghcMode (hsc_dflags env)) }
275 getEpsVar :: TcRnIf gbl lcl (TcRef ExternalPackageState)
276 getEpsVar = do { env <- getTopEnv; return (hsc_EPS env) }
278 getEps :: TcRnIf gbl lcl ExternalPackageState
279 getEps = do { env <- getTopEnv; readMutVar (hsc_EPS env) }
281 -- | Update the external package state. Returns the second result of the
282 -- modifier function.
284 -- This is an atomic operation and forces evaluation of the modified EPS in
285 -- order to avoid space leaks.
286 updateEps :: (ExternalPackageState -> (ExternalPackageState, a))
288 updateEps upd_fn = do
289 traceIf (text "updating EPS")
291 atomicUpdMutVar' eps_var upd_fn
293 -- | Update the external package state.
295 -- This is an atomic operation and forces evaluation of the modified EPS in
296 -- order to avoid space leaks.
297 updateEps_ :: (ExternalPackageState -> ExternalPackageState)
299 updateEps_ upd_fn = do
300 traceIf (text "updating EPS_")
302 atomicUpdMutVar' eps_var (\eps -> (upd_fn eps, ()))
304 getHpt :: TcRnIf gbl lcl HomePackageTable
305 getHpt = do { env <- getTopEnv; return (hsc_HPT env) }
307 getEpsAndHpt :: TcRnIf gbl lcl (ExternalPackageState, HomePackageTable)
308 getEpsAndHpt = do { env <- getTopEnv; eps <- readMutVar (hsc_EPS env)
309 ; return (eps, hsc_HPT env) }
312 %************************************************************************
316 %************************************************************************
319 newMetaUnique :: TcM Unique
320 -- The uniques for TcMetaTyVars are allocated specially
321 -- in guaranteed linear order, starting at zero for each module
323 = do { env <- getLclEnv
324 ; let meta_var = tcl_meta env
325 ; uniq <- readMutVar meta_var
326 ; writeMutVar meta_var (incrUnique uniq)
329 newUnique :: TcRnIf gbl lcl Unique
331 = do { env <- getEnv ;
332 let { u_var = env_us env } ;
333 us <- readMutVar u_var ;
334 case takeUniqFromSupply us of { (uniq, us') -> do {
335 writeMutVar u_var us' ;
337 -- NOTE 1: we strictly split the supply, to avoid the possibility of leaving
338 -- a chain of unevaluated supplies behind.
339 -- NOTE 2: we use the uniq in the supply from the MutVar directly, and
340 -- throw away one half of the new split supply. This is safe because this
341 -- is the only place we use that unique. Using the other half of the split
342 -- supply is safer, but slower.
344 newUniqueSupply :: TcRnIf gbl lcl UniqSupply
346 = do { env <- getEnv ;
347 let { u_var = env_us env } ;
348 us <- readMutVar u_var ;
349 case splitUniqSupply us of { (us1,us2) -> do {
350 writeMutVar u_var us1 ;
353 newLocalName :: Name -> TcRnIf gbl lcl Name
354 newLocalName name -- Make a clone
355 = do { uniq <- newUnique
356 ; return (mkInternalName uniq (nameOccName name) (getSrcSpan name)) }
358 newSysLocalIds :: FastString -> [TcType] -> TcRnIf gbl lcl [TcId]
359 newSysLocalIds fs tys
360 = do { us <- newUniqueSupply
361 ; return (zipWith (mkSysLocal fs) (uniqsFromSupply us) tys) }
363 instance MonadUnique (IOEnv (Env gbl lcl)) where
364 getUniqueM = newUnique
365 getUniqueSupplyM = newUniqueSupply
369 %************************************************************************
373 %************************************************************************
376 newTcRef :: a -> TcRnIf gbl lcl (TcRef a)
379 readTcRef :: TcRef a -> TcRnIf gbl lcl a
380 readTcRef = readMutVar
382 writeTcRef :: TcRef a -> a -> TcRnIf gbl lcl ()
383 writeTcRef = writeMutVar
385 updTcRef :: TcRef a -> (a -> a) -> TcRnIf gbl lcl ()
389 %************************************************************************
393 %************************************************************************
396 traceTc :: String -> SDoc -> TcRn ()
399 traceTcN :: Int -> String -> SDoc -> TcRn ()
400 traceTcN level herald doc
401 | level <= opt_TraceLevel = traceOptTcRn Opt_D_dump_tc_trace $
402 hang (text herald) 2 doc
403 | otherwise = return ()
405 traceRn, traceSplice :: SDoc -> TcRn ()
406 traceRn = traceOptTcRn Opt_D_dump_rn_trace
407 traceSplice = traceOptTcRn Opt_D_dump_splices
410 traceIf, traceHiDiffs :: SDoc -> TcRnIf m n ()
411 traceIf = traceOptIf Opt_D_dump_if_trace
412 traceHiDiffs = traceOptIf Opt_D_dump_hi_diffs
415 traceOptIf :: DynFlag -> SDoc -> TcRnIf m n () -- No RdrEnv available, so qualify everything
416 traceOptIf flag doc = ifDOptM flag $
417 liftIO (printForUser stderr alwaysQualify doc)
419 traceOptTcRn :: DynFlag -> SDoc -> TcRn ()
420 -- Output the message, with current location if opt_PprStyle_Debug
421 traceOptTcRn flag doc = ifDOptM flag $ do
424 | opt_PprStyle_Debug = mkLocMessage loc doc
425 | otherwise = doc -- The full location is
426 -- usually way too much
427 ; dumpTcRn real_doc }
429 dumpTcRn :: SDoc -> TcRn ()
430 dumpTcRn doc = do { rdr_env <- getGlobalRdrEnv
432 ; liftIO (printForUser stderr (mkPrintUnqualified dflags rdr_env) doc) }
434 debugDumpTcRn :: SDoc -> TcRn ()
435 debugDumpTcRn doc | opt_NoDebugOutput = return ()
436 | otherwise = dumpTcRn doc
438 dumpOptTcRn :: DynFlag -> SDoc -> TcRn ()
439 dumpOptTcRn flag doc = ifDOptM flag (dumpTcRn doc)
443 %************************************************************************
445 Typechecker global environment
447 %************************************************************************
450 getModule :: TcRn Module
451 getModule = do { env <- getGblEnv; return (tcg_mod env) }
453 setModule :: Module -> TcRn a -> TcRn a
454 setModule mod thing_inside = updGblEnv (\env -> env { tcg_mod = mod }) thing_inside
456 getIsGHCi :: TcRn Bool
457 getIsGHCi = do { mod <- getModule; return (mod == iNTERACTIVE) }
459 tcIsHsBoot :: TcRn Bool
460 tcIsHsBoot = do { env <- getGblEnv; return (isHsBoot (tcg_src env)) }
462 getGlobalRdrEnv :: TcRn GlobalRdrEnv
463 getGlobalRdrEnv = do { env <- getGblEnv; return (tcg_rdr_env env) }
465 getRdrEnvs :: TcRn (GlobalRdrEnv, LocalRdrEnv)
466 getRdrEnvs = do { (gbl,lcl) <- getEnvs; return (tcg_rdr_env gbl, tcl_rdr lcl) }
468 getImports :: TcRn ImportAvails
469 getImports = do { env <- getGblEnv; return (tcg_imports env) }
471 getFixityEnv :: TcRn FixityEnv
472 getFixityEnv = do { env <- getGblEnv; return (tcg_fix_env env) }
474 extendFixityEnv :: [(Name,FixItem)] -> RnM a -> RnM a
475 extendFixityEnv new_bit
476 = updGblEnv (\env@(TcGblEnv { tcg_fix_env = old_fix_env }) ->
477 env {tcg_fix_env = extendNameEnvList old_fix_env new_bit})
479 getRecFieldEnv :: TcRn RecFieldEnv
480 getRecFieldEnv = do { env <- getGblEnv; return (tcg_field_env env) }
482 getDeclaredDefaultTys :: TcRn (Maybe [Type])
483 getDeclaredDefaultTys = do { env <- getGblEnv; return (tcg_default env) }
486 %************************************************************************
490 %************************************************************************
493 getSrcSpanM :: TcRn SrcSpan
494 -- Avoid clash with Name.getSrcLoc
495 getSrcSpanM = do { env <- getLclEnv; return (tcl_loc env) }
497 setSrcSpan :: SrcSpan -> TcRn a -> TcRn a
498 setSrcSpan loc thing_inside
499 | isGoodSrcSpan loc = updLclEnv (\env -> env { tcl_loc = loc }) thing_inside
500 | otherwise = thing_inside -- Don't overwrite useful info with useless
502 addLocM :: (a -> TcM b) -> Located a -> TcM b
503 addLocM fn (L loc a) = setSrcSpan loc $ fn a
505 wrapLocM :: (a -> TcM b) -> Located a -> TcM (Located b)
506 wrapLocM fn (L loc a) = setSrcSpan loc $ do b <- fn a; return (L loc b)
508 wrapLocFstM :: (a -> TcM (b,c)) -> Located a -> TcM (Located b, c)
509 wrapLocFstM fn (L loc a) =
514 wrapLocSndM :: (a -> TcM (b,c)) -> Located a -> TcM (b, Located c)
515 wrapLocSndM fn (L loc a) =
524 getErrsVar :: TcRn (TcRef Messages)
525 getErrsVar = do { env <- getLclEnv; return (tcl_errs env) }
527 setErrsVar :: TcRef Messages -> TcRn a -> TcRn a
528 setErrsVar v = updLclEnv (\ env -> env { tcl_errs = v })
530 addErr :: Message -> TcRn () -- Ignores the context stack
531 addErr msg = do { loc <- getSrcSpanM ; addErrAt loc msg }
533 failWith :: Message -> TcRn a
534 failWith msg = addErr msg >> failM
536 addErrAt :: SrcSpan -> Message -> TcRn ()
537 -- addErrAt is mainly (exclusively?) used by the renamer, where
538 -- tidying is not an issue, but it's all lazy so the extra
539 -- work doesn't matter
540 addErrAt loc msg = do { ctxt <- getErrCtxt
541 ; tidy_env <- tcInitTidyEnv
542 ; err_info <- mkErrInfo tidy_env ctxt
543 ; addLongErrAt loc msg err_info }
545 addErrs :: [(SrcSpan,Message)] -> TcRn ()
546 addErrs msgs = mapM_ add msgs
548 add (loc,msg) = addErrAt loc msg
550 addWarn :: Message -> TcRn ()
551 addWarn msg = addReport (ptext (sLit "Warning:") <+> msg) empty
553 addWarnAt :: SrcSpan -> Message -> TcRn ()
554 addWarnAt loc msg = addReportAt loc (ptext (sLit "Warning:") <+> msg) empty
556 checkErr :: Bool -> Message -> TcRn ()
557 -- Add the error if the bool is False
558 checkErr ok msg = unless ok (addErr msg)
560 warnIf :: Bool -> Message -> TcRn ()
561 warnIf True msg = addWarn msg
562 warnIf False _ = return ()
564 addMessages :: Messages -> TcRn ()
565 addMessages (m_warns, m_errs)
566 = do { errs_var <- getErrsVar ;
567 (warns, errs) <- readTcRef errs_var ;
568 writeTcRef errs_var (warns `unionBags` m_warns,
569 errs `unionBags` m_errs) }
571 discardWarnings :: TcRn a -> TcRn a
572 -- Ignore warnings inside the thing inside;
573 -- used to ignore-unused-variable warnings inside derived code
574 -- With -dppr-debug, the effects is switched off, so you can still see
575 -- what warnings derived code would give
576 discardWarnings thing_inside
577 | opt_PprStyle_Debug = thing_inside
579 = do { errs_var <- newTcRef emptyMessages
580 ; result <- setErrsVar errs_var thing_inside
581 ; (_warns, errs) <- readTcRef errs_var
582 ; addMessages (emptyBag, errs)
587 %************************************************************************
589 Shared error message stuff: renamer and typechecker
591 %************************************************************************
594 addReport :: Message -> Message -> TcRn ()
595 addReport msg extra_info = do loc <- getSrcSpanM; addReportAt loc msg extra_info
597 addReportAt :: SrcSpan -> Message -> Message -> TcRn ()
598 addReportAt loc msg extra_info
599 = do { errs_var <- getErrsVar ;
600 rdr_env <- getGlobalRdrEnv ;
602 let { warn = mkLongWarnMsg loc (mkPrintUnqualified dflags rdr_env)
604 (warns, errs) <- readTcRef errs_var ;
605 writeTcRef errs_var (warns `snocBag` warn, errs) }
607 addLongErrAt :: SrcSpan -> Message -> Message -> TcRn ()
608 addLongErrAt loc msg extra
609 = do { traceTc "Adding error:" (mkLocMessage loc (msg $$ extra)) ;
610 errs_var <- getErrsVar ;
611 rdr_env <- getGlobalRdrEnv ;
613 let { err = mkLongErrMsg loc (mkPrintUnqualified dflags rdr_env) msg extra } ;
614 (warns, errs) <- readTcRef errs_var ;
615 writeTcRef errs_var (warns, errs `snocBag` err) }
617 dumpDerivingInfo :: SDoc -> TcM ()
619 = do { dflags <- getDOpts
620 ; when (dopt Opt_D_dump_deriv dflags) $ do
621 { rdr_env <- getGlobalRdrEnv
622 ; let unqual = mkPrintUnqualified dflags rdr_env
623 ; liftIO (putMsgWith dflags unqual doc) } }
628 try_m :: TcRn r -> TcRn (Either IOEnvFailure r)
629 -- Does try_m, with a debug-trace on failure
631 = do { mb_r <- tryM thing ;
633 Left exn -> do { traceTc "tryTc/recoverM recovering from" $
634 text (showException exn)
636 Right _ -> return mb_r }
638 -----------------------
639 recoverM :: TcRn r -- Recovery action; do this if the main one fails
640 -> TcRn r -- Main action: do this first
642 -- Errors in 'thing' are retained
643 recoverM recover thing
644 = do { mb_res <- try_m thing ;
647 Right res -> return res }
650 -----------------------
651 mapAndRecoverM :: (a -> TcRn b) -> [a] -> TcRn [b]
652 -- Drop elements of the input that fail, so the result
653 -- list can be shorter than the argument list
654 mapAndRecoverM _ [] = return []
655 mapAndRecoverM f (x:xs) = do { mb_r <- try_m (f x)
656 ; rs <- mapAndRecoverM f xs
657 ; return (case mb_r of
662 -----------------------
663 tryTc :: TcRn a -> TcRn (Messages, Maybe a)
664 -- (tryTc m) executes m, and returns
665 -- Just r, if m succeeds (returning r)
666 -- Nothing, if m fails
667 -- It also returns all the errors and warnings accumulated by m
668 -- It always succeeds (never raises an exception)
670 = do { errs_var <- newTcRef emptyMessages ;
671 res <- try_m (setErrsVar errs_var m) ;
672 msgs <- readTcRef errs_var ;
673 return (msgs, case res of
675 Right val -> Just val)
676 -- The exception is always the IOEnv built-in
677 -- in exception; see IOEnv.failM
680 -----------------------
681 tryTcErrs :: TcRn a -> TcRn (Messages, Maybe a)
682 -- Run the thing, returning
683 -- Just r, if m succceeds with no error messages
684 -- Nothing, if m fails, or if it succeeds but has error messages
685 -- Either way, the messages are returned; even in the Just case
686 -- there might be warnings
688 = do { (msgs, res) <- tryTc thing
690 ; let errs_found = errorsFound dflags msgs
691 ; return (msgs, case res of
693 Just val | errs_found -> Nothing
694 | otherwise -> Just val)
697 -----------------------
698 tryTcLIE :: TcM a -> TcM (Messages, Maybe a)
699 -- Just like tryTcErrs, except that it ensures that the LIE
700 -- for the thing is propagated only if there are no errors
701 -- Hence it's restricted to the type-check monad
702 tryTcLIE thing_inside
703 = do { ((msgs, mb_res), lie) <- captureConstraints (tryTcErrs thing_inside) ;
705 Nothing -> return (msgs, Nothing)
706 Just val -> do { emitConstraints lie; return (msgs, Just val) }
709 -----------------------
710 tryTcLIE_ :: TcM r -> TcM r -> TcM r
711 -- (tryTcLIE_ r m) tries m;
712 -- if m succeeds with no error messages, it's the answer
713 -- otherwise tryTcLIE_ drops everything from m and tries r instead.
714 tryTcLIE_ recover main
715 = do { (msgs, mb_res) <- tryTcLIE main
717 Just val -> do { addMessages msgs -- There might be warnings
719 Nothing -> recover -- Discard all msgs
722 -----------------------
723 checkNoErrs :: TcM r -> TcM r
724 -- (checkNoErrs m) succeeds iff m succeeds and generates no errors
725 -- If m fails then (checkNoErrsTc m) fails.
726 -- If m succeeds, it checks whether m generated any errors messages
727 -- (it might have recovered internally)
728 -- If so, it fails too.
729 -- Regardless, any errors generated by m are propagated to the enclosing context.
731 = do { (msgs, mb_res) <- tryTcLIE main
735 Just val -> return val
738 ifErrsM :: TcRn r -> TcRn r -> TcRn r
739 -- ifErrsM bale_out main
740 -- does 'bale_out' if there are errors in errors collection
741 -- otherwise does 'main'
742 ifErrsM bale_out normal
743 = do { errs_var <- getErrsVar ;
744 msgs <- readTcRef errs_var ;
746 if errorsFound dflags msgs then
751 failIfErrsM :: TcRn ()
752 -- Useful to avoid error cascades
753 failIfErrsM = ifErrsM failM (return ())
757 %************************************************************************
759 Context management for the type checker
761 %************************************************************************
764 getErrCtxt :: TcM [ErrCtxt]
765 getErrCtxt = do { env <- getLclEnv; return (tcl_ctxt env) }
767 setErrCtxt :: [ErrCtxt] -> TcM a -> TcM a
768 setErrCtxt ctxt = updLclEnv (\ env -> env { tcl_ctxt = ctxt })
770 addErrCtxt :: Message -> TcM a -> TcM a
771 addErrCtxt msg = addErrCtxtM (\env -> return (env, msg))
773 addErrCtxtM :: (TidyEnv -> TcM (TidyEnv, Message)) -> TcM a -> TcM a
774 addErrCtxtM ctxt = updCtxt (\ ctxts -> (False, ctxt) : ctxts)
776 addLandmarkErrCtxt :: Message -> TcM a -> TcM a
777 addLandmarkErrCtxt msg = updCtxt (\ctxts -> (True, \env -> return (env,msg)) : ctxts)
779 -- Helper function for the above
780 updCtxt :: ([ErrCtxt] -> [ErrCtxt]) -> TcM a -> TcM a
781 updCtxt upd = updLclEnv (\ env@(TcLclEnv { tcl_ctxt = ctxt }) ->
782 env { tcl_ctxt = upd ctxt })
784 -- Conditionally add an error context
785 maybeAddErrCtxt :: Maybe Message -> TcM a -> TcM a
786 maybeAddErrCtxt (Just msg) thing_inside = addErrCtxt msg thing_inside
787 maybeAddErrCtxt Nothing thing_inside = thing_inside
789 popErrCtxt :: TcM a -> TcM a
790 popErrCtxt = updCtxt (\ msgs -> case msgs of { [] -> []; (_ : ms) -> ms })
792 getCtLoc :: orig -> TcM (CtLoc orig)
794 = do { loc <- getSrcSpanM ; env <- getLclEnv ;
795 return (CtLoc origin loc (tcl_ctxt env)) }
797 setCtLoc :: CtLoc orig -> TcM a -> TcM a
798 setCtLoc (CtLoc _ src_loc ctxt) thing_inside
799 = setSrcSpan src_loc (setErrCtxt ctxt thing_inside)
802 %************************************************************************
804 Error message generation (type checker)
806 %************************************************************************
808 The addErrTc functions add an error message, but do not cause failure.
809 The 'M' variants pass a TidyEnv that has already been used to
810 tidy up the message; we then use it to tidy the context messages
813 addErrTc :: Message -> TcM ()
814 addErrTc err_msg = do { env0 <- tcInitTidyEnv
815 ; addErrTcM (env0, err_msg) }
817 addErrsTc :: [Message] -> TcM ()
818 addErrsTc err_msgs = mapM_ addErrTc err_msgs
820 addErrTcM :: (TidyEnv, Message) -> TcM ()
821 addErrTcM (tidy_env, err_msg)
822 = do { ctxt <- getErrCtxt ;
824 add_err_tcm tidy_env err_msg loc ctxt }
827 The failWith functions add an error message and cause failure
830 failWithTc :: Message -> TcM a -- Add an error message and fail
832 = addErrTc err_msg >> failM
834 failWithTcM :: (TidyEnv, Message) -> TcM a -- Add an error message and fail
835 failWithTcM local_and_msg
836 = addErrTcM local_and_msg >> failM
838 checkTc :: Bool -> Message -> TcM () -- Check that the boolean is true
839 checkTc True _ = return ()
840 checkTc False err = failWithTc err
843 Warnings have no 'M' variant, nor failure
846 addWarnTc :: Message -> TcM ()
847 addWarnTc msg = do { env0 <- tcInitTidyEnv
848 ; addWarnTcM (env0, msg) }
850 addWarnTcM :: (TidyEnv, Message) -> TcM ()
851 addWarnTcM (env0, msg)
852 = do { ctxt <- getErrCtxt ;
853 err_info <- mkErrInfo env0 ctxt ;
854 addReport (ptext (sLit "Warning:") <+> msg) err_info }
856 warnTc :: Bool -> Message -> TcM ()
857 warnTc warn_if_true warn_msg
858 | warn_if_true = addWarnTc warn_msg
859 | otherwise = return ()
862 -----------------------------------
865 We initialise the "tidy-env", used for tidying types before printing,
866 by building a reverse map from the in-scope type variables to the
867 OccName that the programmer originally used for them
870 tcInitTidyEnv :: TcM TidyEnv
872 = do { lcl_env <- getLclEnv
873 ; let nm_tv_prs = [ (name, tcGetTyVar "tcInitTidyEnv" ty)
874 | ATyVar name ty <- nameEnvElts (tcl_env lcl_env)
876 ; return (foldl add emptyTidyEnv nm_tv_prs) }
878 add (env,subst) (name, tyvar)
879 = case tidyOccName env (nameOccName name) of
880 (env', occ') -> (env', extendVarEnv subst tyvar tyvar')
882 tyvar' = setTyVarName tyvar name'
883 name' = tidyNameOcc name occ'
886 -----------------------------------
887 Other helper functions
890 add_err_tcm :: TidyEnv -> Message -> SrcSpan
893 add_err_tcm tidy_env err_msg loc ctxt
894 = do { err_info <- mkErrInfo tidy_env ctxt ;
895 addLongErrAt loc err_msg err_info }
897 mkErrInfo :: TidyEnv -> [ErrCtxt] -> TcM SDoc
898 -- Tidy the error info, trimming excessive contexts
902 go :: Int -> TidyEnv -> [ErrCtxt] -> TcM SDoc
903 go _ _ [] = return empty
904 go n env ((is_landmark, ctxt) : ctxts)
905 | is_landmark || n < mAX_CONTEXTS -- Too verbose || opt_PprStyle_Debug
906 = do { (env', msg) <- ctxt env
907 ; let n' = if is_landmark then n else n+1
908 ; rest <- go n' env' ctxts
909 ; return (msg $$ rest) }
913 mAX_CONTEXTS :: Int -- No more than this number of non-landmark contexts
917 debugTc is useful for monadic debugging code
920 debugTc :: TcM () -> TcM ()
923 | otherwise = return ()
926 %************************************************************************
930 %************************************************************************
933 newTcEvBinds :: TcM EvBindsVar
934 newTcEvBinds = do { ref <- newTcRef emptyEvBindMap
936 ; return (EvBindsVar ref uniq) }
938 extendTcEvBinds :: TcEvBinds -> EvVar -> EvTerm -> TcM TcEvBinds
939 extendTcEvBinds binds@(TcEvBinds binds_var) var rhs
940 = do { addTcEvBind binds_var var rhs
942 extendTcEvBinds (EvBinds bnds) var rhs
943 = return (EvBinds (bnds `snocBag` EvBind var rhs))
945 addTcEvBind :: EvBindsVar -> EvVar -> EvTerm -> TcM ()
946 -- Add a binding to the TcEvBinds by side effect
947 addTcEvBind (EvBindsVar ev_ref _) var rhs
948 = do { bnds <- readTcRef ev_ref
949 ; writeTcRef ev_ref (extendEvBinds bnds var rhs) }
951 chooseUniqueOccTc :: (OccSet -> OccName) -> TcM OccName
952 chooseUniqueOccTc fn =
953 do { env <- getGblEnv
954 ; let dfun_n_var = tcg_dfun_n env
955 ; set <- readTcRef dfun_n_var
957 ; writeTcRef dfun_n_var (extendOccSet set occ)
960 getConstraintVar :: TcM (TcRef WantedConstraints)
961 getConstraintVar = do { env <- getLclEnv; return (tcl_lie env) }
963 setConstraintVar :: TcRef WantedConstraints -> TcM a -> TcM a
964 setConstraintVar lie_var = updLclEnv (\ env -> env { tcl_lie = lie_var })
966 emitConstraints :: WantedConstraints -> TcM ()
968 = do { lie_var <- getConstraintVar ;
969 updTcRef lie_var (`andWC` ct) }
971 emitFlat :: WantedEvVar -> TcM ()
973 = do { lie_var <- getConstraintVar ;
974 updTcRef lie_var (`addFlats` unitBag ct) }
976 emitFlats :: Bag WantedEvVar -> TcM ()
978 = do { lie_var <- getConstraintVar ;
979 updTcRef lie_var (`addFlats` ct) }
981 emitImplication :: Implication -> TcM ()
983 = do { lie_var <- getConstraintVar ;
984 updTcRef lie_var (`addImplics` unitBag ct) }
986 emitImplications :: Bag Implication -> TcM ()
988 = do { lie_var <- getConstraintVar ;
989 updTcRef lie_var (`addImplics` ct) }
991 captureConstraints :: TcM a -> TcM (a, WantedConstraints)
992 -- (captureConstraints m) runs m, and returns the type constraints it generates
993 captureConstraints thing_inside
994 = do { lie_var <- newTcRef emptyWC ;
995 res <- updLclEnv (\ env -> env { tcl_lie = lie_var })
997 lie <- readTcRef lie_var ;
1000 captureUntouchables :: TcM a -> TcM (a, Untouchables)
1001 captureUntouchables thing_inside
1002 = do { env <- getLclEnv
1003 ; low_meta <- readTcRef (tcl_meta env)
1004 ; res <- setLclEnv (env { tcl_untch = low_meta })
1006 ; high_meta <- readTcRef (tcl_meta env)
1007 ; return (res, TouchableRange low_meta high_meta) }
1009 isUntouchable :: TcTyVar -> TcM Bool
1010 isUntouchable tv = do { env <- getLclEnv
1011 ; return (varUnique tv < tcl_untch env) }
1013 getLclTypeEnv :: TcM (NameEnv TcTyThing)
1014 getLclTypeEnv = do { env <- getLclEnv; return (tcl_env env) }
1016 setLclTypeEnv :: TcLclEnv -> TcM a -> TcM a
1017 -- Set the local type envt, but do *not* disturb other fields,
1018 -- notably the lie_var
1019 setLclTypeEnv lcl_env thing_inside
1020 = updLclEnv upd thing_inside
1022 upd env = env { tcl_env = tcl_env lcl_env,
1023 tcl_tyvars = tcl_tyvars lcl_env }
1027 %************************************************************************
1029 Template Haskell context
1031 %************************************************************************
1034 recordThUse :: TcM ()
1035 recordThUse = do { env <- getGblEnv; writeTcRef (tcg_th_used env) True }
1037 keepAliveTc :: Id -> TcM () -- Record the name in the keep-alive set
1039 | isLocalId id = do { env <- getGblEnv;
1040 ; updTcRef (tcg_keep env) (`addOneToNameSet` idName id) }
1041 | otherwise = return ()
1043 keepAliveSetTc :: NameSet -> TcM () -- Record the name in the keep-alive set
1044 keepAliveSetTc ns = do { env <- getGblEnv;
1045 ; updTcRef (tcg_keep env) (`unionNameSets` ns) }
1047 getStage :: TcM ThStage
1048 getStage = do { env <- getLclEnv; return (tcl_th_ctxt env) }
1050 setStage :: ThStage -> TcM a -> TcM a
1051 setStage s = updLclEnv (\ env -> env { tcl_th_ctxt = s })
1055 %************************************************************************
1057 Stuff for the renamer's local env
1059 %************************************************************************
1062 getLocalRdrEnv :: RnM LocalRdrEnv
1063 getLocalRdrEnv = do { env <- getLclEnv; return (tcl_rdr env) }
1065 setLocalRdrEnv :: LocalRdrEnv -> RnM a -> RnM a
1066 setLocalRdrEnv rdr_env thing_inside
1067 = updLclEnv (\env -> env {tcl_rdr = rdr_env}) thing_inside
1071 %************************************************************************
1073 Stuff for interface decls
1075 %************************************************************************
1078 mkIfLclEnv :: Module -> SDoc -> IfLclEnv
1079 mkIfLclEnv mod loc = IfLclEnv { if_mod = mod,
1081 if_tv_env = emptyUFM,
1082 if_id_env = emptyUFM }
1084 initIfaceTcRn :: IfG a -> TcRn a
1085 initIfaceTcRn thing_inside
1086 = do { tcg_env <- getGblEnv
1087 ; let { if_env = IfGblEnv { if_rec_types = Just (tcg_mod tcg_env, get_type_env) }
1088 ; get_type_env = readTcRef (tcg_type_env_var tcg_env) }
1089 ; setEnvs (if_env, ()) thing_inside }
1091 initIfaceExtCore :: IfL a -> TcRn a
1092 initIfaceExtCore thing_inside
1093 = do { tcg_env <- getGblEnv
1094 ; let { mod = tcg_mod tcg_env
1095 ; doc = ptext (sLit "External Core file for") <+> quotes (ppr mod)
1096 ; if_env = IfGblEnv {
1097 if_rec_types = Just (mod, return (tcg_type_env tcg_env)) }
1098 ; if_lenv = mkIfLclEnv mod doc
1100 ; setEnvs (if_env, if_lenv) thing_inside }
1102 initIfaceCheck :: HscEnv -> IfG a -> IO a
1103 -- Used when checking the up-to-date-ness of the old Iface
1104 -- Initialise the environment with no useful info at all
1105 initIfaceCheck hsc_env do_this
1106 = do let rec_types = case hsc_type_env_var hsc_env of
1107 Just (mod,var) -> Just (mod, readTcRef var)
1109 gbl_env = IfGblEnv { if_rec_types = rec_types }
1110 initTcRnIf 'i' hsc_env gbl_env () do_this
1112 initIfaceTc :: ModIface
1113 -> (TcRef TypeEnv -> IfL a) -> TcRnIf gbl lcl a
1114 -- Used when type-checking checking an up-to-date interface file
1115 -- No type envt from the current module, but we do know the module dependencies
1116 initIfaceTc iface do_this
1117 = do { tc_env_var <- newTcRef emptyTypeEnv
1118 ; let { gbl_env = IfGblEnv { if_rec_types = Just (mod, readTcRef tc_env_var) } ;
1119 ; if_lenv = mkIfLclEnv mod doc
1121 ; setEnvs (gbl_env, if_lenv) (do_this tc_env_var)
1124 mod = mi_module iface
1125 doc = ptext (sLit "The interface for") <+> quotes (ppr mod)
1127 initIfaceRules :: HscEnv -> ModGuts -> IfG a -> IO a
1128 -- Used when sucking in new Rules in SimplCore
1129 -- We have available the type envt of the module being compiled, and we must use it
1130 initIfaceRules hsc_env guts do_this
1132 type_info = (mg_module guts, return (mg_types guts))
1133 ; gbl_env = IfGblEnv { if_rec_types = Just type_info } ;
1136 -- Run the thing; any exceptions just bubble out from here
1137 ; initTcRnIf 'i' hsc_env gbl_env () do_this
1140 initIfaceLcl :: Module -> SDoc -> IfL a -> IfM lcl a
1141 initIfaceLcl mod loc_doc thing_inside
1142 = setLclEnv (mkIfLclEnv mod loc_doc) thing_inside
1144 getIfModule :: IfL Module
1145 getIfModule = do { env <- getLclEnv; return (if_mod env) }
1147 --------------------
1148 failIfM :: Message -> IfL a
1149 -- The Iface monad doesn't have a place to accumulate errors, so we
1150 -- just fall over fast if one happens; it "shouldnt happen".
1151 -- We use IfL here so that we can get context info out of the local env
1153 = do { env <- getLclEnv
1154 ; let full_msg = (if_loc env <> colon) $$ nest 2 msg
1155 ; liftIO (printErrs (full_msg defaultErrStyle))
1158 --------------------
1159 forkM_maybe :: SDoc -> IfL a -> IfL (Maybe a)
1160 -- Run thing_inside in an interleaved thread.
1161 -- It shares everything with the parent thread, so this is DANGEROUS.
1163 -- It returns Nothing if the computation fails
1165 -- It's used for lazily type-checking interface
1166 -- signatures, which is pretty benign
1168 forkM_maybe doc thing_inside
1169 = do { unsafeInterleaveM $
1170 do { traceIf (text "Starting fork {" <+> doc)
1172 updLclEnv (\env -> env { if_loc = if_loc env $$ doc }) $
1175 Right r -> do { traceIf (text "} ending fork" <+> doc)
1179 -- Bleat about errors in the forked thread, if -ddump-if-trace is on
1180 -- Otherwise we silently discard errors. Errors can legitimately
1181 -- happen when compiling interface signatures (see tcInterfaceSigs)
1182 ifDOptM Opt_D_dump_if_trace
1183 (print_errs (hang (text "forkM failed:" <+> doc)
1184 2 (text (show exn))))
1186 ; traceIf (text "} ending fork (badly)" <+> doc)
1190 print_errs sdoc = liftIO (printErrs (sdoc defaultErrStyle))
1192 forkM :: SDoc -> IfL a -> IfL a
1193 forkM doc thing_inside
1194 = do { mb_res <- forkM_maybe doc thing_inside
1195 ; return (case mb_res of
1196 Nothing -> pgmError "Cannot continue after interface file error"
1197 -- pprPanic "forkM" doc