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,
120 tcg_dfun_n = dfun_n_var,
122 tcg_doc_hdr = Nothing,
128 tcl_loc = mkGeneralSrcSpan (fsLit "Top level"),
130 tcl_rdr = emptyLocalRdrEnv,
131 tcl_th_ctxt = topStage,
132 tcl_arrow_ctxt = NoArrowCtxt,
133 tcl_env = emptyNameEnv,
134 tcl_tyvars = tvs_var,
137 tcl_untch = initTyVarUnique
141 -- OK, here's the business end!
142 maybe_res <- initTcRnIf 'a' hsc_env gbl_env lcl_env $
143 do { r <- tryM do_this
145 Right res -> return (Just res)
146 Left _ -> return Nothing } ;
148 -- Check for unsolved constraints
149 lie <- readIORef lie_var ;
152 else pprPanic "initTc: unsolved constraints"
153 (pprWantedsWithLocs lie) ;
155 -- Collect any error messages
156 msgs <- readIORef errs_var ;
158 let { dflags = hsc_dflags hsc_env
159 ; final_res | errorsFound dflags msgs = Nothing
160 | otherwise = maybe_res } ;
162 return (msgs, final_res)
165 initTcPrintErrors -- Used from the interactive loop only
169 -> IO (Messages, Maybe r)
171 initTcPrintErrors env mod todo = initTc env HsSrcFile False mod todo
174 %************************************************************************
178 %************************************************************************
182 initTcRnIf :: Char -- Tag for unique supply
187 initTcRnIf uniq_tag hsc_env gbl_env lcl_env thing_inside
188 = do { us <- mkSplitUniqSupply uniq_tag ;
189 ; us_var <- newIORef us ;
191 ; let { env = Env { env_top = hsc_env,
196 ; runIOEnv env thing_inside
200 %************************************************************************
204 %************************************************************************
207 getTopEnv :: TcRnIf gbl lcl HscEnv
208 getTopEnv = do { env <- getEnv; return (env_top env) }
210 getGblEnv :: TcRnIf gbl lcl gbl
211 getGblEnv = do { env <- getEnv; return (env_gbl env) }
213 updGblEnv :: (gbl -> gbl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
214 updGblEnv upd = updEnv (\ env@(Env { env_gbl = gbl }) ->
215 env { env_gbl = upd gbl })
217 setGblEnv :: gbl -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
218 setGblEnv gbl_env = updEnv (\ env -> env { env_gbl = gbl_env })
220 getLclEnv :: TcRnIf gbl lcl lcl
221 getLclEnv = do { env <- getEnv; return (env_lcl env) }
223 updLclEnv :: (lcl -> lcl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
224 updLclEnv upd = updEnv (\ env@(Env { env_lcl = lcl }) ->
225 env { env_lcl = upd lcl })
227 setLclEnv :: lcl' -> TcRnIf gbl lcl' a -> TcRnIf gbl lcl a
228 setLclEnv lcl_env = updEnv (\ env -> env { env_lcl = lcl_env })
230 getEnvs :: TcRnIf gbl lcl (gbl, lcl)
231 getEnvs = do { env <- getEnv; return (env_gbl env, env_lcl env) }
233 setEnvs :: (gbl', lcl') -> TcRnIf gbl' lcl' a -> TcRnIf gbl lcl a
234 setEnvs (gbl_env, lcl_env) = updEnv (\ env -> env { env_gbl = gbl_env, env_lcl = lcl_env })
241 getDOpts :: TcRnIf gbl lcl DynFlags
242 getDOpts = do { env <- getTopEnv; return (hsc_dflags env) }
244 xoptM :: ExtensionFlag -> TcRnIf gbl lcl Bool
245 xoptM flag = do { dflags <- getDOpts; return (xopt flag dflags) }
247 doptM :: DynFlag -> TcRnIf gbl lcl Bool
248 doptM flag = do { dflags <- getDOpts; return (dopt flag dflags) }
250 -- XXX setOptM and unsetOptM operate on different types. One should be renamed.
252 setOptM :: ExtensionFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
253 setOptM flag = updEnv (\ env@(Env { env_top = top }) ->
254 env { env_top = top { hsc_dflags = xopt_set (hsc_dflags top) flag}} )
256 unsetOptM :: DynFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
257 unsetOptM flag = updEnv (\ env@(Env { env_top = top }) ->
258 env { env_top = top { hsc_dflags = dopt_unset (hsc_dflags top) flag}} )
260 -- | Do it flag is true
261 ifDOptM :: DynFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl ()
262 ifDOptM flag thing_inside = do { b <- doptM flag;
263 if b then thing_inside else return () }
265 ifXOptM :: ExtensionFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl ()
266 ifXOptM flag thing_inside = do { b <- xoptM flag;
267 if b then thing_inside else return () }
269 getGhcMode :: TcRnIf gbl lcl GhcMode
270 getGhcMode = do { env <- getTopEnv; return (ghcMode (hsc_dflags env)) }
274 getEpsVar :: TcRnIf gbl lcl (TcRef ExternalPackageState)
275 getEpsVar = do { env <- getTopEnv; return (hsc_EPS env) }
277 getEps :: TcRnIf gbl lcl ExternalPackageState
278 getEps = do { env <- getTopEnv; readMutVar (hsc_EPS env) }
280 -- | Update the external package state. Returns the second result of the
281 -- modifier function.
283 -- This is an atomic operation and forces evaluation of the modified EPS in
284 -- order to avoid space leaks.
285 updateEps :: (ExternalPackageState -> (ExternalPackageState, a))
287 updateEps upd_fn = do
288 traceIf (text "updating EPS")
290 atomicUpdMutVar' eps_var upd_fn
292 -- | Update the external package state.
294 -- This is an atomic operation and forces evaluation of the modified EPS in
295 -- order to avoid space leaks.
296 updateEps_ :: (ExternalPackageState -> ExternalPackageState)
298 updateEps_ upd_fn = do
299 traceIf (text "updating EPS_")
301 atomicUpdMutVar' eps_var (\eps -> (upd_fn eps, ()))
303 getHpt :: TcRnIf gbl lcl HomePackageTable
304 getHpt = do { env <- getTopEnv; return (hsc_HPT env) }
306 getEpsAndHpt :: TcRnIf gbl lcl (ExternalPackageState, HomePackageTable)
307 getEpsAndHpt = do { env <- getTopEnv; eps <- readMutVar (hsc_EPS env)
308 ; return (eps, hsc_HPT env) }
311 %************************************************************************
315 %************************************************************************
318 newMetaUnique :: TcM Unique
319 -- The uniques for TcMetaTyVars are allocated specially
320 -- in guaranteed linear order, starting at zero for each module
322 = do { env <- getLclEnv
323 ; let meta_var = tcl_meta env
324 ; uniq <- readMutVar meta_var
325 ; writeMutVar meta_var (incrUnique uniq)
328 newUnique :: TcRnIf gbl lcl Unique
330 = do { env <- getEnv ;
331 let { u_var = env_us env } ;
332 us <- readMutVar u_var ;
333 case takeUniqFromSupply us of { (uniq, us') -> do {
334 writeMutVar u_var us' ;
336 -- NOTE 1: we strictly split the supply, to avoid the possibility of leaving
337 -- a chain of unevaluated supplies behind.
338 -- NOTE 2: we use the uniq in the supply from the MutVar directly, and
339 -- throw away one half of the new split supply. This is safe because this
340 -- is the only place we use that unique. Using the other half of the split
341 -- supply is safer, but slower.
343 newUniqueSupply :: TcRnIf gbl lcl UniqSupply
345 = do { env <- getEnv ;
346 let { u_var = env_us env } ;
347 us <- readMutVar u_var ;
348 case splitUniqSupply us of { (us1,us2) -> do {
349 writeMutVar u_var us1 ;
352 newLocalName :: Name -> TcRnIf gbl lcl Name
353 newLocalName name -- Make a clone
354 = do { uniq <- newUnique
355 ; return (mkInternalName uniq (nameOccName name) (getSrcSpan name)) }
357 newSysLocalIds :: FastString -> [TcType] -> TcRnIf gbl lcl [TcId]
358 newSysLocalIds fs tys
359 = do { us <- newUniqueSupply
360 ; return (zipWith (mkSysLocal fs) (uniqsFromSupply us) tys) }
362 instance MonadUnique (IOEnv (Env gbl lcl)) where
363 getUniqueM = newUnique
364 getUniqueSupplyM = newUniqueSupply
368 %************************************************************************
372 %************************************************************************
375 newTcRef :: a -> TcRnIf gbl lcl (TcRef a)
378 readTcRef :: TcRef a -> TcRnIf gbl lcl a
379 readTcRef = readMutVar
381 writeTcRef :: TcRef a -> a -> TcRnIf gbl lcl ()
382 writeTcRef = writeMutVar
384 updTcRef :: TcRef a -> (a -> a) -> TcRnIf gbl lcl ()
388 %************************************************************************
392 %************************************************************************
395 traceTc :: String -> SDoc -> TcRn ()
398 traceTcN :: Int -> String -> SDoc -> TcRn ()
399 traceTcN level herald doc
400 | level <= opt_TraceLevel = traceOptTcRn Opt_D_dump_tc_trace $
401 hang (text herald) 2 doc
402 | otherwise = return ()
404 traceRn, traceSplice :: SDoc -> TcRn ()
405 traceRn = traceOptTcRn Opt_D_dump_rn_trace
406 traceSplice = traceOptTcRn Opt_D_dump_splices
409 traceIf, traceHiDiffs :: SDoc -> TcRnIf m n ()
410 traceIf = traceOptIf Opt_D_dump_if_trace
411 traceHiDiffs = traceOptIf Opt_D_dump_hi_diffs
414 traceOptIf :: DynFlag -> SDoc -> TcRnIf m n () -- No RdrEnv available, so qualify everything
415 traceOptIf flag doc = ifDOptM flag $
416 liftIO (printForUser stderr alwaysQualify doc)
418 traceOptTcRn :: DynFlag -> SDoc -> TcRn ()
419 -- Output the message, with current location if opt_PprStyle_Debug
420 traceOptTcRn flag doc = ifDOptM flag $ do
423 | opt_PprStyle_Debug = mkLocMessage loc doc
424 | otherwise = doc -- The full location is
425 -- usually way too much
426 ; dumpTcRn real_doc }
428 dumpTcRn :: SDoc -> TcRn ()
429 dumpTcRn doc = do { rdr_env <- getGlobalRdrEnv
431 ; liftIO (printForUser stderr (mkPrintUnqualified dflags rdr_env) doc) }
433 debugDumpTcRn :: SDoc -> TcRn ()
434 debugDumpTcRn doc | opt_NoDebugOutput = return ()
435 | otherwise = dumpTcRn doc
437 dumpOptTcRn :: DynFlag -> SDoc -> TcRn ()
438 dumpOptTcRn flag doc = ifDOptM flag (dumpTcRn doc)
442 %************************************************************************
444 Typechecker global environment
446 %************************************************************************
449 getModule :: TcRn Module
450 getModule = do { env <- getGblEnv; return (tcg_mod env) }
452 setModule :: Module -> TcRn a -> TcRn a
453 setModule mod thing_inside = updGblEnv (\env -> env { tcg_mod = mod }) thing_inside
455 getIsGHCi :: TcRn Bool
456 getIsGHCi = do { mod <- getModule; return (mod == iNTERACTIVE) }
458 tcIsHsBoot :: TcRn Bool
459 tcIsHsBoot = do { env <- getGblEnv; return (isHsBoot (tcg_src env)) }
461 getGlobalRdrEnv :: TcRn GlobalRdrEnv
462 getGlobalRdrEnv = do { env <- getGblEnv; return (tcg_rdr_env env) }
464 getRdrEnvs :: TcRn (GlobalRdrEnv, LocalRdrEnv)
465 getRdrEnvs = do { (gbl,lcl) <- getEnvs; return (tcg_rdr_env gbl, tcl_rdr lcl) }
467 getImports :: TcRn ImportAvails
468 getImports = do { env <- getGblEnv; return (tcg_imports env) }
470 getFixityEnv :: TcRn FixityEnv
471 getFixityEnv = do { env <- getGblEnv; return (tcg_fix_env env) }
473 extendFixityEnv :: [(Name,FixItem)] -> RnM a -> RnM a
474 extendFixityEnv new_bit
475 = updGblEnv (\env@(TcGblEnv { tcg_fix_env = old_fix_env }) ->
476 env {tcg_fix_env = extendNameEnvList old_fix_env new_bit})
478 getRecFieldEnv :: TcRn RecFieldEnv
479 getRecFieldEnv = do { env <- getGblEnv; return (tcg_field_env env) }
481 getDeclaredDefaultTys :: TcRn (Maybe [Type])
482 getDeclaredDefaultTys = do { env <- getGblEnv; return (tcg_default env) }
485 %************************************************************************
489 %************************************************************************
492 getSrcSpanM :: TcRn SrcSpan
493 -- Avoid clash with Name.getSrcLoc
494 getSrcSpanM = do { env <- getLclEnv; return (tcl_loc env) }
496 setSrcSpan :: SrcSpan -> TcRn a -> TcRn a
497 setSrcSpan loc thing_inside
498 | isGoodSrcSpan loc = updLclEnv (\env -> env { tcl_loc = loc }) thing_inside
499 | otherwise = thing_inside -- Don't overwrite useful info with useless
501 addLocM :: (a -> TcM b) -> Located a -> TcM b
502 addLocM fn (L loc a) = setSrcSpan loc $ fn a
504 wrapLocM :: (a -> TcM b) -> Located a -> TcM (Located b)
505 wrapLocM fn (L loc a) = setSrcSpan loc $ do b <- fn a; return (L loc b)
507 wrapLocFstM :: (a -> TcM (b,c)) -> Located a -> TcM (Located b, c)
508 wrapLocFstM fn (L loc a) =
513 wrapLocSndM :: (a -> TcM (b,c)) -> Located a -> TcM (b, Located c)
514 wrapLocSndM fn (L loc a) =
523 getErrsVar :: TcRn (TcRef Messages)
524 getErrsVar = do { env <- getLclEnv; return (tcl_errs env) }
526 setErrsVar :: TcRef Messages -> TcRn a -> TcRn a
527 setErrsVar v = updLclEnv (\ env -> env { tcl_errs = v })
529 addErr :: Message -> TcRn () -- Ignores the context stack
530 addErr msg = do { loc <- getSrcSpanM ; addErrAt loc msg }
532 failWith :: Message -> TcRn a
533 failWith msg = addErr msg >> failM
535 addErrAt :: SrcSpan -> Message -> TcRn ()
536 -- addErrAt is mainly (exclusively?) used by the renamer, where
537 -- tidying is not an issue, but it's all lazy so the extra
538 -- work doesn't matter
539 addErrAt loc msg = do { ctxt <- getErrCtxt
540 ; tidy_env <- tcInitTidyEnv
541 ; err_info <- mkErrInfo tidy_env ctxt
542 ; addLongErrAt loc msg err_info }
544 addErrs :: [(SrcSpan,Message)] -> TcRn ()
545 addErrs msgs = mapM_ add msgs
547 add (loc,msg) = addErrAt loc msg
549 addWarn :: Message -> TcRn ()
550 addWarn msg = addReport (ptext (sLit "Warning:") <+> msg) empty
552 addWarnAt :: SrcSpan -> Message -> TcRn ()
553 addWarnAt loc msg = addReportAt loc (ptext (sLit "Warning:") <+> msg) empty
555 checkErr :: Bool -> Message -> TcRn ()
556 -- Add the error if the bool is False
557 checkErr ok msg = unless ok (addErr msg)
559 warnIf :: Bool -> Message -> TcRn ()
560 warnIf True msg = addWarn msg
561 warnIf False _ = return ()
563 addMessages :: Messages -> TcRn ()
564 addMessages (m_warns, m_errs)
565 = do { errs_var <- getErrsVar ;
566 (warns, errs) <- readTcRef errs_var ;
567 writeTcRef errs_var (warns `unionBags` m_warns,
568 errs `unionBags` m_errs) }
570 discardWarnings :: TcRn a -> TcRn a
571 -- Ignore warnings inside the thing inside;
572 -- used to ignore-unused-variable warnings inside derived code
573 -- With -dppr-debug, the effects is switched off, so you can still see
574 -- what warnings derived code would give
575 discardWarnings thing_inside
576 | opt_PprStyle_Debug = thing_inside
578 = do { errs_var <- newTcRef emptyMessages
579 ; result <- setErrsVar errs_var thing_inside
580 ; (_warns, errs) <- readTcRef errs_var
581 ; addMessages (emptyBag, errs)
586 %************************************************************************
588 Shared error message stuff: renamer and typechecker
590 %************************************************************************
593 addReport :: Message -> Message -> TcRn ()
594 addReport msg extra_info = do loc <- getSrcSpanM; addReportAt loc msg extra_info
596 addReportAt :: SrcSpan -> Message -> Message -> TcRn ()
597 addReportAt loc msg extra_info
598 = do { errs_var <- getErrsVar ;
599 rdr_env <- getGlobalRdrEnv ;
601 let { warn = mkLongWarnMsg loc (mkPrintUnqualified dflags rdr_env)
603 (warns, errs) <- readTcRef errs_var ;
604 writeTcRef errs_var (warns `snocBag` warn, errs) }
606 addLongErrAt :: SrcSpan -> Message -> Message -> TcRn ()
607 addLongErrAt loc msg extra
608 = do { traceTc "Adding error:" (mkLocMessage loc (msg $$ extra)) ;
609 errs_var <- getErrsVar ;
610 rdr_env <- getGlobalRdrEnv ;
612 let { err = mkLongErrMsg loc (mkPrintUnqualified dflags rdr_env) msg extra } ;
613 (warns, errs) <- readTcRef errs_var ;
614 writeTcRef errs_var (warns, errs `snocBag` err) }
616 dumpDerivingInfo :: SDoc -> TcM ()
618 = do { dflags <- getDOpts
619 ; when (dopt Opt_D_dump_deriv dflags) $ do
620 { rdr_env <- getGlobalRdrEnv
621 ; let unqual = mkPrintUnqualified dflags rdr_env
622 ; liftIO (putMsgWith dflags unqual doc) } }
627 try_m :: TcRn r -> TcRn (Either IOEnvFailure r)
628 -- Does try_m, with a debug-trace on failure
630 = do { mb_r <- tryM thing ;
632 Left exn -> do { traceTc "tryTc/recoverM recovering from" $
633 text (showException exn)
635 Right _ -> return mb_r }
637 -----------------------
638 recoverM :: TcRn r -- Recovery action; do this if the main one fails
639 -> TcRn r -- Main action: do this first
641 -- Errors in 'thing' are retained
642 recoverM recover thing
643 = do { mb_res <- try_m thing ;
646 Right res -> return res }
649 -----------------------
650 mapAndRecoverM :: (a -> TcRn b) -> [a] -> TcRn [b]
651 -- Drop elements of the input that fail, so the result
652 -- list can be shorter than the argument list
653 mapAndRecoverM _ [] = return []
654 mapAndRecoverM f (x:xs) = do { mb_r <- try_m (f x)
655 ; rs <- mapAndRecoverM f xs
656 ; return (case mb_r of
661 -----------------------
662 tryTc :: TcRn a -> TcRn (Messages, Maybe a)
663 -- (tryTc m) executes m, and returns
664 -- Just r, if m succeeds (returning r)
665 -- Nothing, if m fails
666 -- It also returns all the errors and warnings accumulated by m
667 -- It always succeeds (never raises an exception)
669 = do { errs_var <- newTcRef emptyMessages ;
670 res <- try_m (setErrsVar errs_var m) ;
671 msgs <- readTcRef errs_var ;
672 return (msgs, case res of
674 Right val -> Just val)
675 -- The exception is always the IOEnv built-in
676 -- in exception; see IOEnv.failM
679 -----------------------
680 tryTcErrs :: TcRn a -> TcRn (Messages, Maybe a)
681 -- Run the thing, returning
682 -- Just r, if m succceeds with no error messages
683 -- Nothing, if m fails, or if it succeeds but has error messages
684 -- Either way, the messages are returned; even in the Just case
685 -- there might be warnings
687 = do { (msgs, res) <- tryTc thing
689 ; let errs_found = errorsFound dflags msgs
690 ; return (msgs, case res of
692 Just val | errs_found -> Nothing
693 | otherwise -> Just val)
696 -----------------------
697 tryTcLIE :: TcM a -> TcM (Messages, Maybe a)
698 -- Just like tryTcErrs, except that it ensures that the LIE
699 -- for the thing is propagated only if there are no errors
700 -- Hence it's restricted to the type-check monad
701 tryTcLIE thing_inside
702 = do { ((msgs, mb_res), lie) <- captureConstraints (tryTcErrs thing_inside) ;
704 Nothing -> return (msgs, Nothing)
705 Just val -> do { emitConstraints lie; return (msgs, Just val) }
708 -----------------------
709 tryTcLIE_ :: TcM r -> TcM r -> TcM r
710 -- (tryTcLIE_ r m) tries m;
711 -- if m succeeds with no error messages, it's the answer
712 -- otherwise tryTcLIE_ drops everything from m and tries r instead.
713 tryTcLIE_ recover main
714 = do { (msgs, mb_res) <- tryTcLIE main
716 Just val -> do { addMessages msgs -- There might be warnings
718 Nothing -> recover -- Discard all msgs
721 -----------------------
722 checkNoErrs :: TcM r -> TcM r
723 -- (checkNoErrs m) succeeds iff m succeeds and generates no errors
724 -- If m fails then (checkNoErrsTc m) fails.
725 -- If m succeeds, it checks whether m generated any errors messages
726 -- (it might have recovered internally)
727 -- If so, it fails too.
728 -- Regardless, any errors generated by m are propagated to the enclosing context.
730 = do { (msgs, mb_res) <- tryTcLIE main
734 Just val -> return val
737 ifErrsM :: TcRn r -> TcRn r -> TcRn r
738 -- ifErrsM bale_out main
739 -- does 'bale_out' if there are errors in errors collection
740 -- otherwise does 'main'
741 ifErrsM bale_out normal
742 = do { errs_var <- getErrsVar ;
743 msgs <- readTcRef errs_var ;
745 if errorsFound dflags msgs then
750 failIfErrsM :: TcRn ()
751 -- Useful to avoid error cascades
752 failIfErrsM = ifErrsM failM (return ())
756 %************************************************************************
758 Context management for the type checker
760 %************************************************************************
763 getErrCtxt :: TcM [ErrCtxt]
764 getErrCtxt = do { env <- getLclEnv; return (tcl_ctxt env) }
766 setErrCtxt :: [ErrCtxt] -> TcM a -> TcM a
767 setErrCtxt ctxt = updLclEnv (\ env -> env { tcl_ctxt = ctxt })
769 addErrCtxt :: Message -> TcM a -> TcM a
770 addErrCtxt msg = addErrCtxtM (\env -> return (env, msg))
772 addErrCtxtM :: (TidyEnv -> TcM (TidyEnv, Message)) -> TcM a -> TcM a
773 addErrCtxtM ctxt = updCtxt (\ ctxts -> (False, ctxt) : ctxts)
775 addLandmarkErrCtxt :: Message -> TcM a -> TcM a
776 addLandmarkErrCtxt msg = updCtxt (\ctxts -> (True, \env -> return (env,msg)) : ctxts)
778 -- Helper function for the above
779 updCtxt :: ([ErrCtxt] -> [ErrCtxt]) -> TcM a -> TcM a
780 updCtxt upd = updLclEnv (\ env@(TcLclEnv { tcl_ctxt = ctxt }) ->
781 env { tcl_ctxt = upd ctxt })
783 -- Conditionally add an error context
784 maybeAddErrCtxt :: Maybe Message -> TcM a -> TcM a
785 maybeAddErrCtxt (Just msg) thing_inside = addErrCtxt msg thing_inside
786 maybeAddErrCtxt Nothing thing_inside = thing_inside
788 popErrCtxt :: TcM a -> TcM a
789 popErrCtxt = updCtxt (\ msgs -> case msgs of { [] -> []; (_ : ms) -> ms })
791 getCtLoc :: orig -> TcM (CtLoc orig)
793 = do { loc <- getSrcSpanM ; env <- getLclEnv ;
794 return (CtLoc origin loc (tcl_ctxt env)) }
796 setCtLoc :: CtLoc orig -> TcM a -> TcM a
797 setCtLoc (CtLoc _ src_loc ctxt) thing_inside
798 = setSrcSpan src_loc (setErrCtxt ctxt thing_inside)
801 %************************************************************************
803 Error message generation (type checker)
805 %************************************************************************
807 The addErrTc functions add an error message, but do not cause failure.
808 The 'M' variants pass a TidyEnv that has already been used to
809 tidy up the message; we then use it to tidy the context messages
812 addErrTc :: Message -> TcM ()
813 addErrTc err_msg = do { env0 <- tcInitTidyEnv
814 ; addErrTcM (env0, err_msg) }
816 addErrsTc :: [Message] -> TcM ()
817 addErrsTc err_msgs = mapM_ addErrTc err_msgs
819 addErrTcM :: (TidyEnv, Message) -> TcM ()
820 addErrTcM (tidy_env, err_msg)
821 = do { ctxt <- getErrCtxt ;
823 add_err_tcm tidy_env err_msg loc ctxt }
826 The failWith functions add an error message and cause failure
829 failWithTc :: Message -> TcM a -- Add an error message and fail
831 = addErrTc err_msg >> failM
833 failWithTcM :: (TidyEnv, Message) -> TcM a -- Add an error message and fail
834 failWithTcM local_and_msg
835 = addErrTcM local_and_msg >> failM
837 checkTc :: Bool -> Message -> TcM () -- Check that the boolean is true
838 checkTc True _ = return ()
839 checkTc False err = failWithTc err
842 Warnings have no 'M' variant, nor failure
845 addWarnTc :: Message -> TcM ()
846 addWarnTc msg = do { env0 <- tcInitTidyEnv
847 ; addWarnTcM (env0, msg) }
849 addWarnTcM :: (TidyEnv, Message) -> TcM ()
850 addWarnTcM (env0, msg)
851 = do { ctxt <- getErrCtxt ;
852 err_info <- mkErrInfo env0 ctxt ;
853 addReport (ptext (sLit "Warning:") <+> msg) err_info }
855 warnTc :: Bool -> Message -> TcM ()
856 warnTc warn_if_true warn_msg
857 | warn_if_true = addWarnTc warn_msg
858 | otherwise = return ()
861 -----------------------------------
864 We initialise the "tidy-env", used for tidying types before printing,
865 by building a reverse map from the in-scope type variables to the
866 OccName that the programmer originally used for them
869 tcInitTidyEnv :: TcM TidyEnv
871 = do { lcl_env <- getLclEnv
872 ; let nm_tv_prs = [ (name, tcGetTyVar "tcInitTidyEnv" ty)
873 | ATyVar name ty <- nameEnvElts (tcl_env lcl_env)
875 ; return (foldl add emptyTidyEnv nm_tv_prs) }
877 add (env,subst) (name, tyvar)
878 = case tidyOccName env (nameOccName name) of
879 (env', occ') -> (env', extendVarEnv subst tyvar tyvar')
881 tyvar' = setTyVarName tyvar name'
882 name' = tidyNameOcc name occ'
885 -----------------------------------
886 Other helper functions
889 add_err_tcm :: TidyEnv -> Message -> SrcSpan
892 add_err_tcm tidy_env err_msg loc ctxt
893 = do { err_info <- mkErrInfo tidy_env ctxt ;
894 addLongErrAt loc err_msg err_info }
896 mkErrInfo :: TidyEnv -> [ErrCtxt] -> TcM SDoc
897 -- Tidy the error info, trimming excessive contexts
901 go :: Int -> TidyEnv -> [ErrCtxt] -> TcM SDoc
902 go _ _ [] = return empty
903 go n env ((is_landmark, ctxt) : ctxts)
904 | is_landmark || n < mAX_CONTEXTS -- Too verbose || opt_PprStyle_Debug
905 = do { (env', msg) <- ctxt env
906 ; let n' = if is_landmark then n else n+1
907 ; rest <- go n' env' ctxts
908 ; return (msg $$ rest) }
912 mAX_CONTEXTS :: Int -- No more than this number of non-landmark contexts
916 debugTc is useful for monadic debugging code
919 debugTc :: TcM () -> TcM ()
922 | otherwise = return ()
925 %************************************************************************
929 %************************************************************************
932 newTcEvBinds :: TcM EvBindsVar
933 newTcEvBinds = do { ref <- newTcRef emptyEvBindMap
935 ; return (EvBindsVar ref uniq) }
937 extendTcEvBinds :: TcEvBinds -> EvVar -> EvTerm -> TcM TcEvBinds
938 extendTcEvBinds binds@(TcEvBinds binds_var) var rhs
939 = do { addTcEvBind binds_var var rhs
941 extendTcEvBinds (EvBinds bnds) var rhs
942 = return (EvBinds (bnds `snocBag` EvBind var rhs))
944 addTcEvBind :: EvBindsVar -> EvVar -> EvTerm -> TcM ()
945 -- Add a binding to the TcEvBinds by side effect
946 addTcEvBind (EvBindsVar ev_ref _) var rhs
947 = do { bnds <- readTcRef ev_ref
948 ; writeTcRef ev_ref (extendEvBinds bnds var rhs) }
950 chooseUniqueOccTc :: (OccSet -> OccName) -> TcM OccName
951 chooseUniqueOccTc fn =
952 do { env <- getGblEnv
953 ; let dfun_n_var = tcg_dfun_n env
954 ; set <- readTcRef dfun_n_var
956 ; writeTcRef dfun_n_var (extendOccSet set occ)
959 getConstraintVar :: TcM (TcRef WantedConstraints)
960 getConstraintVar = do { env <- getLclEnv; return (tcl_lie env) }
962 setConstraintVar :: TcRef WantedConstraints -> TcM a -> TcM a
963 setConstraintVar lie_var = updLclEnv (\ env -> env { tcl_lie = lie_var })
965 emitConstraints :: WantedConstraints -> TcM ()
967 = do { lie_var <- getConstraintVar ;
968 updTcRef lie_var (`andWC` ct) }
970 emitFlat :: WantedEvVar -> TcM ()
972 = do { lie_var <- getConstraintVar ;
973 updTcRef lie_var (`addFlats` unitBag ct) }
975 emitFlats :: Bag WantedEvVar -> TcM ()
977 = do { lie_var <- getConstraintVar ;
978 updTcRef lie_var (`addFlats` ct) }
980 emitImplication :: Implication -> TcM ()
982 = do { lie_var <- getConstraintVar ;
983 updTcRef lie_var (`addImplics` unitBag ct) }
985 emitImplications :: Bag Implication -> TcM ()
987 = do { lie_var <- getConstraintVar ;
988 updTcRef lie_var (`addImplics` ct) }
990 captureConstraints :: TcM a -> TcM (a, WantedConstraints)
991 -- (captureConstraints m) runs m, and returns the type constraints it generates
992 captureConstraints thing_inside
993 = do { lie_var <- newTcRef emptyWC ;
994 res <- updLclEnv (\ env -> env { tcl_lie = lie_var })
996 lie <- readTcRef lie_var ;
999 captureUntouchables :: TcM a -> TcM (a, Untouchables)
1000 captureUntouchables thing_inside
1001 = do { env <- getLclEnv
1002 ; low_meta <- readTcRef (tcl_meta env)
1003 ; res <- setLclEnv (env { tcl_untch = low_meta })
1005 ; high_meta <- readTcRef (tcl_meta env)
1006 ; return (res, TouchableRange low_meta high_meta) }
1008 isUntouchable :: TcTyVar -> TcM Bool
1009 isUntouchable tv = do { env <- getLclEnv
1010 ; return (varUnique tv < tcl_untch env) }
1012 getLclTypeEnv :: TcM (NameEnv TcTyThing)
1013 getLclTypeEnv = do { env <- getLclEnv; return (tcl_env env) }
1015 setLclTypeEnv :: TcLclEnv -> TcM a -> TcM a
1016 -- Set the local type envt, but do *not* disturb other fields,
1017 -- notably the lie_var
1018 setLclTypeEnv lcl_env thing_inside
1019 = updLclEnv upd thing_inside
1021 upd env = env { tcl_env = tcl_env lcl_env,
1022 tcl_tyvars = tcl_tyvars lcl_env }
1026 %************************************************************************
1028 Template Haskell context
1030 %************************************************************************
1033 recordThUse :: TcM ()
1034 recordThUse = do { env <- getGblEnv; writeTcRef (tcg_th_used env) True }
1036 keepAliveTc :: Id -> TcM () -- Record the name in the keep-alive set
1038 | isLocalId id = do { env <- getGblEnv;
1039 ; updTcRef (tcg_keep env) (`addOneToNameSet` idName id) }
1040 | otherwise = return ()
1042 keepAliveSetTc :: NameSet -> TcM () -- Record the name in the keep-alive set
1043 keepAliveSetTc ns = do { env <- getGblEnv;
1044 ; updTcRef (tcg_keep env) (`unionNameSets` ns) }
1046 getStage :: TcM ThStage
1047 getStage = do { env <- getLclEnv; return (tcl_th_ctxt env) }
1049 setStage :: ThStage -> TcM a -> TcM a
1050 setStage s = updLclEnv (\ env -> env { tcl_th_ctxt = s })
1054 %************************************************************************
1056 Stuff for the renamer's local env
1058 %************************************************************************
1061 getLocalRdrEnv :: RnM LocalRdrEnv
1062 getLocalRdrEnv = do { env <- getLclEnv; return (tcl_rdr env) }
1064 setLocalRdrEnv :: LocalRdrEnv -> RnM a -> RnM a
1065 setLocalRdrEnv rdr_env thing_inside
1066 = updLclEnv (\env -> env {tcl_rdr = rdr_env}) thing_inside
1070 %************************************************************************
1072 Stuff for interface decls
1074 %************************************************************************
1077 mkIfLclEnv :: Module -> SDoc -> IfLclEnv
1078 mkIfLclEnv mod loc = IfLclEnv { if_mod = mod,
1080 if_tv_env = emptyUFM,
1081 if_id_env = emptyUFM }
1083 initIfaceTcRn :: IfG a -> TcRn a
1084 initIfaceTcRn thing_inside
1085 = do { tcg_env <- getGblEnv
1086 ; let { if_env = IfGblEnv { if_rec_types = Just (tcg_mod tcg_env, get_type_env) }
1087 ; get_type_env = readTcRef (tcg_type_env_var tcg_env) }
1088 ; setEnvs (if_env, ()) thing_inside }
1090 initIfaceExtCore :: IfL a -> TcRn a
1091 initIfaceExtCore thing_inside
1092 = do { tcg_env <- getGblEnv
1093 ; let { mod = tcg_mod tcg_env
1094 ; doc = ptext (sLit "External Core file for") <+> quotes (ppr mod)
1095 ; if_env = IfGblEnv {
1096 if_rec_types = Just (mod, return (tcg_type_env tcg_env)) }
1097 ; if_lenv = mkIfLclEnv mod doc
1099 ; setEnvs (if_env, if_lenv) thing_inside }
1101 initIfaceCheck :: HscEnv -> IfG a -> IO a
1102 -- Used when checking the up-to-date-ness of the old Iface
1103 -- Initialise the environment with no useful info at all
1104 initIfaceCheck hsc_env do_this
1105 = do let rec_types = case hsc_type_env_var hsc_env of
1106 Just (mod,var) -> Just (mod, readTcRef var)
1108 gbl_env = IfGblEnv { if_rec_types = rec_types }
1109 initTcRnIf 'i' hsc_env gbl_env () do_this
1111 initIfaceTc :: ModIface
1112 -> (TcRef TypeEnv -> IfL a) -> TcRnIf gbl lcl a
1113 -- Used when type-checking checking an up-to-date interface file
1114 -- No type envt from the current module, but we do know the module dependencies
1115 initIfaceTc iface do_this
1116 = do { tc_env_var <- newTcRef emptyTypeEnv
1117 ; let { gbl_env = IfGblEnv { if_rec_types = Just (mod, readTcRef tc_env_var) } ;
1118 ; if_lenv = mkIfLclEnv mod doc
1120 ; setEnvs (gbl_env, if_lenv) (do_this tc_env_var)
1123 mod = mi_module iface
1124 doc = ptext (sLit "The interface for") <+> quotes (ppr mod)
1126 initIfaceRules :: HscEnv -> ModGuts -> IfG a -> IO a
1127 -- Used when sucking in new Rules in SimplCore
1128 -- We have available the type envt of the module being compiled, and we must use it
1129 initIfaceRules hsc_env guts do_this
1131 type_info = (mg_module guts, return (mg_types guts))
1132 ; gbl_env = IfGblEnv { if_rec_types = Just type_info } ;
1135 -- Run the thing; any exceptions just bubble out from here
1136 ; initTcRnIf 'i' hsc_env gbl_env () do_this
1139 initIfaceLcl :: Module -> SDoc -> IfL a -> IfM lcl a
1140 initIfaceLcl mod loc_doc thing_inside
1141 = setLclEnv (mkIfLclEnv mod loc_doc) thing_inside
1143 getIfModule :: IfL Module
1144 getIfModule = do { env <- getLclEnv; return (if_mod env) }
1146 --------------------
1147 failIfM :: Message -> IfL a
1148 -- The Iface monad doesn't have a place to accumulate errors, so we
1149 -- just fall over fast if one happens; it "shouldnt happen".
1150 -- We use IfL here so that we can get context info out of the local env
1152 = do { env <- getLclEnv
1153 ; let full_msg = (if_loc env <> colon) $$ nest 2 msg
1154 ; liftIO (printErrs (full_msg defaultErrStyle))
1157 --------------------
1158 forkM_maybe :: SDoc -> IfL a -> IfL (Maybe a)
1159 -- Run thing_inside in an interleaved thread.
1160 -- It shares everything with the parent thread, so this is DANGEROUS.
1162 -- It returns Nothing if the computation fails
1164 -- It's used for lazily type-checking interface
1165 -- signatures, which is pretty benign
1167 forkM_maybe doc thing_inside
1168 = do { unsafeInterleaveM $
1169 do { traceIf (text "Starting fork {" <+> doc)
1171 updLclEnv (\env -> env { if_loc = if_loc env $$ doc }) $
1174 Right r -> do { traceIf (text "} ending fork" <+> doc)
1178 -- Bleat about errors in the forked thread, if -ddump-if-trace is on
1179 -- Otherwise we silently discard errors. Errors can legitimately
1180 -- happen when compiling interface signatures (see tcInterfaceSigs)
1181 ifDOptM Opt_D_dump_if_trace
1182 (print_errs (hang (text "forkM failed:" <+> doc)
1183 2 (text (show exn))))
1185 ; traceIf (text "} ending fork (badly)" <+> doc)
1189 print_errs sdoc = liftIO (printErrs (sdoc defaultErrStyle))
1191 forkM :: SDoc -> IfL a -> IfL a
1192 forkM doc thing_inside
1193 = do { mb_res <- forkM_maybe doc thing_inside
1194 ; return (case mb_res of
1195 Nothing -> pgmError "Cannot continue after interface file error"
1196 -- pprPanic "forkM" doc