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,
143 -- OK, here's the business end!
144 maybe_res <- initTcRnIf 'a' hsc_env gbl_env lcl_env $
145 do { r <- tryM do_this
147 Right res -> return (Just res)
148 Left _ -> return Nothing } ;
150 -- Check for unsolved constraints
151 lie <- readIORef lie_var ;
154 else pprPanic "initTc: unsolved constraints"
155 (pprWantedsWithLocs lie) ;
157 -- Collect any error messages
158 msgs <- readIORef errs_var ;
160 let { dflags = hsc_dflags hsc_env
161 ; final_res | errorsFound dflags msgs = Nothing
162 | otherwise = maybe_res } ;
164 return (msgs, final_res)
167 initTcPrintErrors -- Used from the interactive loop only
171 -> IO (Messages, Maybe r)
173 initTcPrintErrors env mod todo = initTc env HsSrcFile False mod todo
176 %************************************************************************
180 %************************************************************************
184 initTcRnIf :: Char -- Tag for unique supply
189 initTcRnIf uniq_tag hsc_env gbl_env lcl_env thing_inside
190 = do { us <- mkSplitUniqSupply uniq_tag ;
191 ; us_var <- newIORef us ;
193 ; let { env = Env { env_top = hsc_env,
198 ; runIOEnv env thing_inside
202 %************************************************************************
206 %************************************************************************
209 getTopEnv :: TcRnIf gbl lcl HscEnv
210 getTopEnv = do { env <- getEnv; return (env_top env) }
212 getGblEnv :: TcRnIf gbl lcl gbl
213 getGblEnv = do { env <- getEnv; return (env_gbl env) }
215 updGblEnv :: (gbl -> gbl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
216 updGblEnv upd = updEnv (\ env@(Env { env_gbl = gbl }) ->
217 env { env_gbl = upd gbl })
219 setGblEnv :: gbl -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
220 setGblEnv gbl_env = updEnv (\ env -> env { env_gbl = gbl_env })
222 getLclEnv :: TcRnIf gbl lcl lcl
223 getLclEnv = do { env <- getEnv; return (env_lcl env) }
225 updLclEnv :: (lcl -> lcl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
226 updLclEnv upd = updEnv (\ env@(Env { env_lcl = lcl }) ->
227 env { env_lcl = upd lcl })
229 setLclEnv :: lcl' -> TcRnIf gbl lcl' a -> TcRnIf gbl lcl a
230 setLclEnv lcl_env = updEnv (\ env -> env { env_lcl = lcl_env })
232 getEnvs :: TcRnIf gbl lcl (gbl, lcl)
233 getEnvs = do { env <- getEnv; return (env_gbl env, env_lcl env) }
235 setEnvs :: (gbl', lcl') -> TcRnIf gbl' lcl' a -> TcRnIf gbl lcl a
236 setEnvs (gbl_env, lcl_env) = updEnv (\ env -> env { env_gbl = gbl_env, env_lcl = lcl_env })
243 getDOpts :: TcRnIf gbl lcl DynFlags
244 getDOpts = do { env <- getTopEnv; return (hsc_dflags env) }
246 xoptM :: ExtensionFlag -> TcRnIf gbl lcl Bool
247 xoptM flag = do { dflags <- getDOpts; return (xopt flag dflags) }
249 doptM :: DynFlag -> TcRnIf gbl lcl Bool
250 doptM flag = do { dflags <- getDOpts; return (dopt flag dflags) }
252 -- XXX setOptM and unsetOptM operate on different types. One should be renamed.
254 setOptM :: ExtensionFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
255 setOptM flag = updEnv (\ env@(Env { env_top = top }) ->
256 env { env_top = top { hsc_dflags = xopt_set (hsc_dflags top) flag}} )
258 unsetOptM :: DynFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
259 unsetOptM flag = updEnv (\ env@(Env { env_top = top }) ->
260 env { env_top = top { hsc_dflags = dopt_unset (hsc_dflags top) flag}} )
262 -- | Do it flag is true
263 ifDOptM :: DynFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl ()
264 ifDOptM flag thing_inside = do { b <- doptM flag;
265 if b then thing_inside else return () }
267 ifXOptM :: ExtensionFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl ()
268 ifXOptM flag thing_inside = do { b <- xoptM flag;
269 if b then thing_inside else return () }
271 getGhcMode :: TcRnIf gbl lcl GhcMode
272 getGhcMode = do { env <- getTopEnv; return (ghcMode (hsc_dflags env)) }
276 getEpsVar :: TcRnIf gbl lcl (TcRef ExternalPackageState)
277 getEpsVar = do { env <- getTopEnv; return (hsc_EPS env) }
279 getEps :: TcRnIf gbl lcl ExternalPackageState
280 getEps = do { env <- getTopEnv; readMutVar (hsc_EPS env) }
282 -- | Update the external package state. Returns the second result of the
283 -- modifier function.
285 -- This is an atomic operation and forces evaluation of the modified EPS in
286 -- order to avoid space leaks.
287 updateEps :: (ExternalPackageState -> (ExternalPackageState, a))
289 updateEps upd_fn = do
290 traceIf (text "updating EPS")
292 atomicUpdMutVar' eps_var upd_fn
294 -- | Update the external package state.
296 -- This is an atomic operation and forces evaluation of the modified EPS in
297 -- order to avoid space leaks.
298 updateEps_ :: (ExternalPackageState -> ExternalPackageState)
300 updateEps_ upd_fn = do
301 traceIf (text "updating EPS_")
303 atomicUpdMutVar' eps_var (\eps -> (upd_fn eps, ()))
305 getHpt :: TcRnIf gbl lcl HomePackageTable
306 getHpt = do { env <- getTopEnv; return (hsc_HPT env) }
308 getEpsAndHpt :: TcRnIf gbl lcl (ExternalPackageState, HomePackageTable)
309 getEpsAndHpt = do { env <- getTopEnv; eps <- readMutVar (hsc_EPS env)
310 ; return (eps, hsc_HPT env) }
313 %************************************************************************
317 %************************************************************************
320 newMetaUnique :: TcM Unique
321 -- The uniques for TcMetaTyVars are allocated specially
322 -- in guaranteed linear order, starting at zero for each module
324 = do { env <- getLclEnv
325 ; let meta_var = tcl_meta env
326 ; uniq <- readMutVar meta_var
327 ; writeMutVar meta_var (incrUnique uniq)
330 newUnique :: TcRnIf gbl lcl Unique
332 = do { env <- getEnv ;
333 let { u_var = env_us env } ;
334 us <- readMutVar u_var ;
335 case takeUniqFromSupply us of { (uniq, us') -> do {
336 writeMutVar u_var us' ;
338 -- NOTE 1: we strictly split the supply, to avoid the possibility of leaving
339 -- a chain of unevaluated supplies behind.
340 -- NOTE 2: we use the uniq in the supply from the MutVar directly, and
341 -- throw away one half of the new split supply. This is safe because this
342 -- is the only place we use that unique. Using the other half of the split
343 -- supply is safer, but slower.
345 newUniqueSupply :: TcRnIf gbl lcl UniqSupply
347 = do { env <- getEnv ;
348 let { u_var = env_us env } ;
349 us <- readMutVar u_var ;
350 case splitUniqSupply us of { (us1,us2) -> do {
351 writeMutVar u_var us1 ;
354 newLocalName :: Name -> TcRnIf gbl lcl Name
355 newLocalName name -- Make a clone
356 = do { uniq <- newUnique
357 ; return (mkInternalName uniq (nameOccName name) (getSrcSpan name)) }
359 newSysLocalIds :: FastString -> [TcType] -> TcRnIf gbl lcl [TcId]
360 newSysLocalIds fs tys
361 = do { us <- newUniqueSupply
362 ; return (zipWith (mkSysLocal fs) (uniqsFromSupply us) tys) }
364 instance MonadUnique (IOEnv (Env gbl lcl)) where
365 getUniqueM = newUnique
366 getUniqueSupplyM = newUniqueSupply
370 %************************************************************************
374 %************************************************************************
377 newTcRef :: a -> TcRnIf gbl lcl (TcRef a)
380 readTcRef :: TcRef a -> TcRnIf gbl lcl a
381 readTcRef = readMutVar
383 writeTcRef :: TcRef a -> a -> TcRnIf gbl lcl ()
384 writeTcRef = writeMutVar
386 updTcRef :: TcRef a -> (a -> a) -> TcRnIf gbl lcl ()
390 %************************************************************************
394 %************************************************************************
397 traceTc :: String -> SDoc -> TcRn ()
400 traceTcN :: Int -> String -> SDoc -> TcRn ()
401 traceTcN level herald doc
402 | level <= opt_TraceLevel = traceOptTcRn Opt_D_dump_tc_trace $
403 hang (text herald) 2 doc
404 | otherwise = return ()
406 traceRn, traceSplice :: SDoc -> TcRn ()
407 traceRn = traceOptTcRn Opt_D_dump_rn_trace
408 traceSplice = traceOptTcRn Opt_D_dump_splices
411 traceIf, traceHiDiffs :: SDoc -> TcRnIf m n ()
412 traceIf = traceOptIf Opt_D_dump_if_trace
413 traceHiDiffs = traceOptIf Opt_D_dump_hi_diffs
416 traceOptIf :: DynFlag -> SDoc -> TcRnIf m n () -- No RdrEnv available, so qualify everything
417 traceOptIf flag doc = ifDOptM flag $
418 liftIO (printForUser stderr alwaysQualify doc)
420 traceOptTcRn :: DynFlag -> SDoc -> TcRn ()
421 -- Output the message, with current location if opt_PprStyle_Debug
422 traceOptTcRn flag doc = ifDOptM flag $ do
425 | opt_PprStyle_Debug = mkLocMessage loc doc
426 | otherwise = doc -- The full location is
427 -- usually way too much
428 ; dumpTcRn real_doc }
430 dumpTcRn :: SDoc -> TcRn ()
431 dumpTcRn doc = do { rdr_env <- getGlobalRdrEnv
433 ; liftIO (printForUser stderr (mkPrintUnqualified dflags rdr_env) doc) }
435 debugDumpTcRn :: SDoc -> TcRn ()
436 debugDumpTcRn doc | opt_NoDebugOutput = return ()
437 | otherwise = dumpTcRn doc
439 dumpOptTcRn :: DynFlag -> SDoc -> TcRn ()
440 dumpOptTcRn flag doc = ifDOptM flag (dumpTcRn doc)
444 %************************************************************************
446 Typechecker global environment
448 %************************************************************************
451 getModule :: TcRn Module
452 getModule = do { env <- getGblEnv; return (tcg_mod env) }
454 setModule :: Module -> TcRn a -> TcRn a
455 setModule mod thing_inside = updGblEnv (\env -> env { tcg_mod = mod }) thing_inside
457 getIsGHCi :: TcRn Bool
458 getIsGHCi = do { mod <- getModule; return (mod == iNTERACTIVE) }
460 tcIsHsBoot :: TcRn Bool
461 tcIsHsBoot = do { env <- getGblEnv; return (isHsBoot (tcg_src env)) }
463 getGlobalRdrEnv :: TcRn GlobalRdrEnv
464 getGlobalRdrEnv = do { env <- getGblEnv; return (tcg_rdr_env env) }
466 getRdrEnvs :: TcRn (GlobalRdrEnv, LocalRdrEnv)
467 getRdrEnvs = do { (gbl,lcl) <- getEnvs; return (tcg_rdr_env gbl, tcl_rdr lcl) }
469 getImports :: TcRn ImportAvails
470 getImports = do { env <- getGblEnv; return (tcg_imports env) }
472 getFixityEnv :: TcRn FixityEnv
473 getFixityEnv = do { env <- getGblEnv; return (tcg_fix_env env) }
475 extendFixityEnv :: [(Name,FixItem)] -> RnM a -> RnM a
476 extendFixityEnv new_bit
477 = updGblEnv (\env@(TcGblEnv { tcg_fix_env = old_fix_env }) ->
478 env {tcg_fix_env = extendNameEnvList old_fix_env new_bit})
480 getRecFieldEnv :: TcRn RecFieldEnv
481 getRecFieldEnv = do { env <- getGblEnv; return (tcg_field_env env) }
483 getDeclaredDefaultTys :: TcRn (Maybe [Type])
484 getDeclaredDefaultTys = do { env <- getGblEnv; return (tcg_default env) }
487 %************************************************************************
491 %************************************************************************
494 getSrcSpanM :: TcRn SrcSpan
495 -- Avoid clash with Name.getSrcLoc
496 getSrcSpanM = do { env <- getLclEnv; return (tcl_loc env) }
498 setSrcSpan :: SrcSpan -> TcRn a -> TcRn a
499 setSrcSpan loc thing_inside
500 | isGoodSrcSpan loc = updLclEnv (\env -> env { tcl_loc = loc }) thing_inside
501 | otherwise = thing_inside -- Don't overwrite useful info with useless
503 addLocM :: (a -> TcM b) -> Located a -> TcM b
504 addLocM fn (L loc a) = setSrcSpan loc $ fn a
506 wrapLocM :: (a -> TcM b) -> Located a -> TcM (Located b)
507 wrapLocM fn (L loc a) = setSrcSpan loc $ do b <- fn a; return (L loc b)
509 wrapLocFstM :: (a -> TcM (b,c)) -> Located a -> TcM (Located b, c)
510 wrapLocFstM fn (L loc a) =
515 wrapLocSndM :: (a -> TcM (b,c)) -> Located a -> TcM (b, Located c)
516 wrapLocSndM fn (L loc a) =
525 getErrsVar :: TcRn (TcRef Messages)
526 getErrsVar = do { env <- getLclEnv; return (tcl_errs env) }
528 setErrsVar :: TcRef Messages -> TcRn a -> TcRn a
529 setErrsVar v = updLclEnv (\ env -> env { tcl_errs = v })
531 addErr :: Message -> TcRn () -- Ignores the context stack
532 addErr msg = do { loc <- getSrcSpanM ; addErrAt loc msg }
534 failWith :: Message -> TcRn a
535 failWith msg = addErr msg >> failM
537 addErrAt :: SrcSpan -> Message -> TcRn ()
538 -- addErrAt is mainly (exclusively?) used by the renamer, where
539 -- tidying is not an issue, but it's all lazy so the extra
540 -- work doesn't matter
541 addErrAt loc msg = do { ctxt <- getErrCtxt
542 ; tidy_env <- tcInitTidyEnv
543 ; err_info <- mkErrInfo tidy_env ctxt
544 ; addLongErrAt loc msg err_info }
546 addErrs :: [(SrcSpan,Message)] -> TcRn ()
547 addErrs msgs = mapM_ add msgs
549 add (loc,msg) = addErrAt loc msg
551 addWarn :: Message -> TcRn ()
552 addWarn msg = addReport (ptext (sLit "Warning:") <+> msg) empty
554 addWarnAt :: SrcSpan -> Message -> TcRn ()
555 addWarnAt loc msg = addReportAt loc (ptext (sLit "Warning:") <+> msg) empty
557 checkErr :: Bool -> Message -> TcRn ()
558 -- Add the error if the bool is False
559 checkErr ok msg = unless ok (addErr msg)
561 warnIf :: Bool -> Message -> TcRn ()
562 warnIf True msg = addWarn msg
563 warnIf False _ = return ()
565 addMessages :: Messages -> TcRn ()
566 addMessages (m_warns, m_errs)
567 = do { errs_var <- getErrsVar ;
568 (warns, errs) <- readTcRef errs_var ;
569 writeTcRef errs_var (warns `unionBags` m_warns,
570 errs `unionBags` m_errs) }
572 discardWarnings :: TcRn a -> TcRn a
573 -- Ignore warnings inside the thing inside;
574 -- used to ignore-unused-variable warnings inside derived code
575 -- With -dppr-debug, the effects is switched off, so you can still see
576 -- what warnings derived code would give
577 discardWarnings thing_inside
578 | opt_PprStyle_Debug = thing_inside
580 = do { errs_var <- newTcRef emptyMessages
581 ; result <- setErrsVar errs_var thing_inside
582 ; (_warns, errs) <- readTcRef errs_var
583 ; addMessages (emptyBag, errs)
588 %************************************************************************
590 Shared error message stuff: renamer and typechecker
592 %************************************************************************
595 addReport :: Message -> Message -> TcRn ()
596 addReport msg extra_info = do loc <- getSrcSpanM; addReportAt loc msg extra_info
598 addReportAt :: SrcSpan -> Message -> Message -> TcRn ()
599 addReportAt loc msg extra_info
600 = do { errs_var <- getErrsVar ;
601 rdr_env <- getGlobalRdrEnv ;
603 let { warn = mkLongWarnMsg loc (mkPrintUnqualified dflags rdr_env)
605 (warns, errs) <- readTcRef errs_var ;
606 writeTcRef errs_var (warns `snocBag` warn, errs) }
608 addLongErrAt :: SrcSpan -> Message -> Message -> TcRn ()
609 addLongErrAt loc msg extra
610 = do { traceTc "Adding error:" (mkLocMessage loc (msg $$ extra)) ;
611 errs_var <- getErrsVar ;
612 rdr_env <- getGlobalRdrEnv ;
614 let { err = mkLongErrMsg loc (mkPrintUnqualified dflags rdr_env) msg extra } ;
615 (warns, errs) <- readTcRef errs_var ;
616 writeTcRef errs_var (warns, errs `snocBag` err) }
618 dumpDerivingInfo :: SDoc -> TcM ()
620 = do { dflags <- getDOpts
621 ; when (dopt Opt_D_dump_deriv dflags) $ do
622 { rdr_env <- getGlobalRdrEnv
623 ; let unqual = mkPrintUnqualified dflags rdr_env
624 ; liftIO (putMsgWith dflags unqual doc) } }
629 try_m :: TcRn r -> TcRn (Either IOEnvFailure r)
630 -- Does try_m, with a debug-trace on failure
632 = do { mb_r <- tryM thing ;
634 Left exn -> do { traceTc "tryTc/recoverM recovering from" $
635 text (showException exn)
637 Right _ -> return mb_r }
639 -----------------------
640 recoverM :: TcRn r -- Recovery action; do this if the main one fails
641 -> TcRn r -- Main action: do this first
643 -- Errors in 'thing' are retained
644 recoverM recover thing
645 = do { mb_res <- try_m thing ;
648 Right res -> return res }
651 -----------------------
652 mapAndRecoverM :: (a -> TcRn b) -> [a] -> TcRn [b]
653 -- Drop elements of the input that fail, so the result
654 -- list can be shorter than the argument list
655 mapAndRecoverM _ [] = return []
656 mapAndRecoverM f (x:xs) = do { mb_r <- try_m (f x)
657 ; rs <- mapAndRecoverM f xs
658 ; return (case mb_r of
663 -----------------------
664 tryTc :: TcRn a -> TcRn (Messages, Maybe a)
665 -- (tryTc m) executes m, and returns
666 -- Just r, if m succeeds (returning r)
667 -- Nothing, if m fails
668 -- It also returns all the errors and warnings accumulated by m
669 -- It always succeeds (never raises an exception)
671 = do { errs_var <- newTcRef emptyMessages ;
672 res <- try_m (setErrsVar errs_var m) ;
673 msgs <- readTcRef errs_var ;
674 return (msgs, case res of
676 Right val -> Just val)
677 -- The exception is always the IOEnv built-in
678 -- in exception; see IOEnv.failM
681 -----------------------
682 tryTcErrs :: TcRn a -> TcRn (Messages, Maybe a)
683 -- Run the thing, returning
684 -- Just r, if m succceeds with no error messages
685 -- Nothing, if m fails, or if it succeeds but has error messages
686 -- Either way, the messages are returned; even in the Just case
687 -- there might be warnings
689 = do { (msgs, res) <- tryTc thing
691 ; let errs_found = errorsFound dflags msgs
692 ; return (msgs, case res of
694 Just val | errs_found -> Nothing
695 | otherwise -> Just val)
698 -----------------------
699 tryTcLIE :: TcM a -> TcM (Messages, Maybe a)
700 -- Just like tryTcErrs, except that it ensures that the LIE
701 -- for the thing is propagated only if there are no errors
702 -- Hence it's restricted to the type-check monad
703 tryTcLIE thing_inside
704 = do { ((msgs, mb_res), lie) <- captureConstraints (tryTcErrs thing_inside) ;
706 Nothing -> return (msgs, Nothing)
707 Just val -> do { emitConstraints lie; return (msgs, Just val) }
710 -----------------------
711 tryTcLIE_ :: TcM r -> TcM r -> TcM r
712 -- (tryTcLIE_ r m) tries m;
713 -- if m succeeds with no error messages, it's the answer
714 -- otherwise tryTcLIE_ drops everything from m and tries r instead.
715 tryTcLIE_ recover main
716 = do { (msgs, mb_res) <- tryTcLIE main
718 Just val -> do { addMessages msgs -- There might be warnings
720 Nothing -> recover -- Discard all msgs
723 -----------------------
724 checkNoErrs :: TcM r -> TcM r
725 -- (checkNoErrs m) succeeds iff m succeeds and generates no errors
726 -- If m fails then (checkNoErrsTc m) fails.
727 -- If m succeeds, it checks whether m generated any errors messages
728 -- (it might have recovered internally)
729 -- If so, it fails too.
730 -- Regardless, any errors generated by m are propagated to the enclosing context.
732 = do { (msgs, mb_res) <- tryTcLIE main
736 Just val -> return val
739 ifErrsM :: TcRn r -> TcRn r -> TcRn r
740 -- ifErrsM bale_out main
741 -- does 'bale_out' if there are errors in errors collection
742 -- otherwise does 'main'
743 ifErrsM bale_out normal
744 = do { errs_var <- getErrsVar ;
745 msgs <- readTcRef errs_var ;
747 if errorsFound dflags msgs then
752 failIfErrsM :: TcRn ()
753 -- Useful to avoid error cascades
754 failIfErrsM = ifErrsM failM (return ())
758 %************************************************************************
760 Context management for the type checker
762 %************************************************************************
765 getErrCtxt :: TcM [ErrCtxt]
766 getErrCtxt = do { env <- getLclEnv; return (tcl_ctxt env) }
768 setErrCtxt :: [ErrCtxt] -> TcM a -> TcM a
769 setErrCtxt ctxt = updLclEnv (\ env -> env { tcl_ctxt = ctxt })
771 addErrCtxt :: Message -> TcM a -> TcM a
772 addErrCtxt msg = addErrCtxtM (\env -> return (env, msg))
774 addErrCtxtM :: (TidyEnv -> TcM (TidyEnv, Message)) -> TcM a -> TcM a
775 addErrCtxtM ctxt = updCtxt (\ ctxts -> (False, ctxt) : ctxts)
777 addLandmarkErrCtxt :: Message -> TcM a -> TcM a
778 addLandmarkErrCtxt msg = updCtxt (\ctxts -> (True, \env -> return (env,msg)) : ctxts)
780 -- Helper function for the above
781 updCtxt :: ([ErrCtxt] -> [ErrCtxt]) -> TcM a -> TcM a
782 updCtxt upd = updLclEnv (\ env@(TcLclEnv { tcl_ctxt = ctxt }) ->
783 env { tcl_ctxt = upd ctxt })
785 -- Conditionally add an error context
786 maybeAddErrCtxt :: Maybe Message -> TcM a -> TcM a
787 maybeAddErrCtxt (Just msg) thing_inside = addErrCtxt msg thing_inside
788 maybeAddErrCtxt Nothing thing_inside = thing_inside
790 popErrCtxt :: TcM a -> TcM a
791 popErrCtxt = updCtxt (\ msgs -> case msgs of { [] -> []; (_ : ms) -> ms })
793 getCtLoc :: orig -> TcM (CtLoc orig)
795 = do { loc <- getSrcSpanM ; env <- getLclEnv ;
796 return (CtLoc origin loc (tcl_ctxt env)) }
798 setCtLoc :: CtLoc orig -> TcM a -> TcM a
799 setCtLoc (CtLoc _ src_loc ctxt) thing_inside
800 = setSrcSpan src_loc (setErrCtxt ctxt thing_inside)
803 %************************************************************************
805 Error message generation (type checker)
807 %************************************************************************
809 The addErrTc functions add an error message, but do not cause failure.
810 The 'M' variants pass a TidyEnv that has already been used to
811 tidy up the message; we then use it to tidy the context messages
814 addErrTc :: Message -> TcM ()
815 addErrTc err_msg = do { env0 <- tcInitTidyEnv
816 ; addErrTcM (env0, err_msg) }
818 addErrsTc :: [Message] -> TcM ()
819 addErrsTc err_msgs = mapM_ addErrTc err_msgs
821 addErrTcM :: (TidyEnv, Message) -> TcM ()
822 addErrTcM (tidy_env, err_msg)
823 = do { ctxt <- getErrCtxt ;
825 add_err_tcm tidy_env err_msg loc ctxt }
828 The failWith functions add an error message and cause failure
831 failWithTc :: Message -> TcM a -- Add an error message and fail
833 = addErrTc err_msg >> failM
835 failWithTcM :: (TidyEnv, Message) -> TcM a -- Add an error message and fail
836 failWithTcM local_and_msg
837 = addErrTcM local_and_msg >> failM
839 checkTc :: Bool -> Message -> TcM () -- Check that the boolean is true
840 checkTc True _ = return ()
841 checkTc False err = failWithTc err
844 Warnings have no 'M' variant, nor failure
847 addWarnTc :: Message -> TcM ()
848 addWarnTc msg = do { env0 <- tcInitTidyEnv
849 ; addWarnTcM (env0, msg) }
851 addWarnTcM :: (TidyEnv, Message) -> TcM ()
852 addWarnTcM (env0, msg)
853 = do { ctxt <- getErrCtxt ;
854 err_info <- mkErrInfo env0 ctxt ;
855 addReport (ptext (sLit "Warning:") <+> msg) err_info }
857 warnTc :: Bool -> Message -> TcM ()
858 warnTc warn_if_true warn_msg
859 | warn_if_true = addWarnTc warn_msg
860 | otherwise = return ()
863 -----------------------------------
866 We initialise the "tidy-env", used for tidying types before printing,
867 by building a reverse map from the in-scope type variables to the
868 OccName that the programmer originally used for them
871 tcInitTidyEnv :: TcM TidyEnv
873 = do { lcl_env <- getLclEnv
874 ; let nm_tv_prs = [ (name, tcGetTyVar "tcInitTidyEnv" ty)
875 | ATyVar name ty <- nameEnvElts (tcl_env lcl_env)
877 ; return (foldl add emptyTidyEnv nm_tv_prs) }
879 add (env,subst) (name, tyvar)
880 = case tidyOccName env (nameOccName name) of
881 (env', occ') -> (env', extendVarEnv subst tyvar tyvar')
883 tyvar' = setTyVarName tyvar name'
884 name' = tidyNameOcc name occ'
887 -----------------------------------
888 Other helper functions
891 add_err_tcm :: TidyEnv -> Message -> SrcSpan
894 add_err_tcm tidy_env err_msg loc ctxt
895 = do { err_info <- mkErrInfo tidy_env ctxt ;
896 addLongErrAt loc err_msg err_info }
898 mkErrInfo :: TidyEnv -> [ErrCtxt] -> TcM SDoc
899 -- Tidy the error info, trimming excessive contexts
903 go :: Int -> TidyEnv -> [ErrCtxt] -> TcM SDoc
904 go _ _ [] = return empty
905 go n env ((is_landmark, ctxt) : ctxts)
906 | is_landmark || n < mAX_CONTEXTS -- Too verbose || opt_PprStyle_Debug
907 = do { (env', msg) <- ctxt env
908 ; let n' = if is_landmark then n else n+1
909 ; rest <- go n' env' ctxts
910 ; return (msg $$ rest) }
914 mAX_CONTEXTS :: Int -- No more than this number of non-landmark contexts
918 debugTc is useful for monadic debugging code
921 debugTc :: TcM () -> TcM ()
924 | otherwise = return ()
927 %************************************************************************
931 %************************************************************************
934 newTcEvBinds :: TcM EvBindsVar
935 newTcEvBinds = do { ref <- newTcRef emptyEvBindMap
937 ; return (EvBindsVar ref uniq) }
939 extendTcEvBinds :: TcEvBinds -> EvVar -> EvTerm -> TcM TcEvBinds
940 extendTcEvBinds binds@(TcEvBinds binds_var) var rhs
941 = do { addTcEvBind binds_var var rhs
943 extendTcEvBinds (EvBinds bnds) var rhs
944 = return (EvBinds (bnds `snocBag` EvBind var rhs))
946 addTcEvBind :: EvBindsVar -> EvVar -> EvTerm -> TcM ()
947 -- Add a binding to the TcEvBinds by side effect
948 addTcEvBind (EvBindsVar ev_ref _) var rhs
949 = do { bnds <- readTcRef ev_ref
950 ; writeTcRef ev_ref (extendEvBinds bnds var rhs) }
952 chooseUniqueOccTc :: (OccSet -> OccName) -> TcM OccName
953 chooseUniqueOccTc fn =
954 do { env <- getGblEnv
955 ; let dfun_n_var = tcg_dfun_n env
956 ; set <- readTcRef dfun_n_var
958 ; writeTcRef dfun_n_var (extendOccSet set occ)
961 getConstraintVar :: TcM (TcRef WantedConstraints)
962 getConstraintVar = do { env <- getLclEnv; return (tcl_lie env) }
964 setConstraintVar :: TcRef WantedConstraints -> TcM a -> TcM a
965 setConstraintVar lie_var = updLclEnv (\ env -> env { tcl_lie = lie_var })
967 emitConstraints :: WantedConstraints -> TcM ()
969 = do { lie_var <- getConstraintVar ;
970 updTcRef lie_var (`andWC` ct) }
972 emitFlat :: WantedEvVar -> TcM ()
974 = do { lie_var <- getConstraintVar ;
975 updTcRef lie_var (`addFlats` unitBag ct) }
977 emitFlats :: Bag WantedEvVar -> TcM ()
979 = do { lie_var <- getConstraintVar ;
980 updTcRef lie_var (`addFlats` ct) }
982 emitImplication :: Implication -> TcM ()
984 = do { lie_var <- getConstraintVar ;
985 updTcRef lie_var (`addImplics` unitBag ct) }
987 emitImplications :: Bag Implication -> TcM ()
989 = do { lie_var <- getConstraintVar ;
990 updTcRef lie_var (`addImplics` ct) }
992 captureConstraints :: TcM a -> TcM (a, WantedConstraints)
993 -- (captureConstraints m) runs m, and returns the type constraints it generates
994 captureConstraints thing_inside
995 = do { lie_var <- newTcRef emptyWC ;
996 res <- updLclEnv (\ env -> env { tcl_lie = lie_var })
998 lie <- readTcRef lie_var ;
1001 captureUntouchables :: TcM a -> TcM (a, Untouchables)
1002 captureUntouchables thing_inside
1003 = do { env <- getLclEnv
1004 ; low_meta <- readTcRef (tcl_meta env)
1005 ; res <- setLclEnv (env { tcl_untch = low_meta })
1007 ; high_meta <- readTcRef (tcl_meta env)
1008 ; return (res, TouchableRange low_meta high_meta) }
1010 isUntouchable :: TcTyVar -> TcM Bool
1011 isUntouchable tv = do { env <- getLclEnv
1012 ; return (varUnique tv < tcl_untch env) }
1014 getLclTypeEnv :: TcM (NameEnv TcTyThing)
1015 getLclTypeEnv = do { env <- getLclEnv; return (tcl_env env) }
1017 setLclTypeEnv :: TcLclEnv -> TcM a -> TcM a
1018 -- Set the local type envt, but do *not* disturb other fields,
1019 -- notably the lie_var
1020 setLclTypeEnv lcl_env thing_inside
1021 = updLclEnv upd thing_inside
1023 upd env = env { tcl_env = tcl_env lcl_env,
1024 tcl_tyvars = tcl_tyvars lcl_env }
1028 %************************************************************************
1030 Template Haskell context
1032 %************************************************************************
1035 recordThUse :: TcM ()
1036 recordThUse = do { env <- getGblEnv; writeTcRef (tcg_th_used env) True }
1038 keepAliveTc :: Id -> TcM () -- Record the name in the keep-alive set
1040 | isLocalId id = do { env <- getGblEnv;
1041 ; updTcRef (tcg_keep env) (`addOneToNameSet` idName id) }
1042 | otherwise = return ()
1044 keepAliveSetTc :: NameSet -> TcM () -- Record the name in the keep-alive set
1045 keepAliveSetTc ns = do { env <- getGblEnv;
1046 ; updTcRef (tcg_keep env) (`unionNameSets` ns) }
1048 getStage :: TcM ThStage
1049 getStage = do { env <- getLclEnv; return (tcl_th_ctxt env) }
1051 setStage :: ThStage -> TcM a -> TcM a
1052 setStage s = updLclEnv (\ env -> env { tcl_th_ctxt = s })
1056 %************************************************************************
1058 Stuff for the renamer's local env
1060 %************************************************************************
1063 getLocalRdrEnv :: RnM LocalRdrEnv
1064 getLocalRdrEnv = do { env <- getLclEnv; return (tcl_rdr env) }
1066 setLocalRdrEnv :: LocalRdrEnv -> RnM a -> RnM a
1067 setLocalRdrEnv rdr_env thing_inside
1068 = updLclEnv (\env -> env {tcl_rdr = rdr_env}) thing_inside
1072 %************************************************************************
1074 Stuff for interface decls
1076 %************************************************************************
1079 mkIfLclEnv :: Module -> SDoc -> IfLclEnv
1080 mkIfLclEnv mod loc = IfLclEnv { if_mod = mod,
1082 if_tv_env = emptyUFM,
1083 if_id_env = emptyUFM }
1085 initIfaceTcRn :: IfG a -> TcRn a
1086 initIfaceTcRn thing_inside
1087 = do { tcg_env <- getGblEnv
1088 ; let { if_env = IfGblEnv { if_rec_types = Just (tcg_mod tcg_env, get_type_env) }
1089 ; get_type_env = readTcRef (tcg_type_env_var tcg_env) }
1090 ; setEnvs (if_env, ()) thing_inside }
1092 initIfaceExtCore :: IfL a -> TcRn a
1093 initIfaceExtCore thing_inside
1094 = do { tcg_env <- getGblEnv
1095 ; let { mod = tcg_mod tcg_env
1096 ; doc = ptext (sLit "External Core file for") <+> quotes (ppr mod)
1097 ; if_env = IfGblEnv {
1098 if_rec_types = Just (mod, return (tcg_type_env tcg_env)) }
1099 ; if_lenv = mkIfLclEnv mod doc
1101 ; setEnvs (if_env, if_lenv) thing_inside }
1103 initIfaceCheck :: HscEnv -> IfG a -> IO a
1104 -- Used when checking the up-to-date-ness of the old Iface
1105 -- Initialise the environment with no useful info at all
1106 initIfaceCheck hsc_env do_this
1107 = do let rec_types = case hsc_type_env_var hsc_env of
1108 Just (mod,var) -> Just (mod, readTcRef var)
1110 gbl_env = IfGblEnv { if_rec_types = rec_types }
1111 initTcRnIf 'i' hsc_env gbl_env () do_this
1113 initIfaceTc :: ModIface
1114 -> (TcRef TypeEnv -> IfL a) -> TcRnIf gbl lcl a
1115 -- Used when type-checking checking an up-to-date interface file
1116 -- No type envt from the current module, but we do know the module dependencies
1117 initIfaceTc iface do_this
1118 = do { tc_env_var <- newTcRef emptyTypeEnv
1119 ; let { gbl_env = IfGblEnv { if_rec_types = Just (mod, readTcRef tc_env_var) } ;
1120 ; if_lenv = mkIfLclEnv mod doc
1122 ; setEnvs (gbl_env, if_lenv) (do_this tc_env_var)
1125 mod = mi_module iface
1126 doc = ptext (sLit "The interface for") <+> quotes (ppr mod)
1128 initIfaceRules :: HscEnv -> ModGuts -> IfG a -> IO a
1129 -- Used when sucking in new Rules in SimplCore
1130 -- We have available the type envt of the module being compiled, and we must use it
1131 initIfaceRules hsc_env guts do_this
1133 type_info = (mg_module guts, return (mg_types guts))
1134 ; gbl_env = IfGblEnv { if_rec_types = Just type_info } ;
1137 -- Run the thing; any exceptions just bubble out from here
1138 ; initTcRnIf 'i' hsc_env gbl_env () do_this
1141 initIfaceLcl :: Module -> SDoc -> IfL a -> IfM lcl a
1142 initIfaceLcl mod loc_doc thing_inside
1143 = setLclEnv (mkIfLclEnv mod loc_doc) thing_inside
1145 getIfModule :: IfL Module
1146 getIfModule = do { env <- getLclEnv; return (if_mod env) }
1148 --------------------
1149 failIfM :: Message -> IfL a
1150 -- The Iface monad doesn't have a place to accumulate errors, so we
1151 -- just fall over fast if one happens; it "shouldnt happen".
1152 -- We use IfL here so that we can get context info out of the local env
1154 = do { env <- getLclEnv
1155 ; let full_msg = (if_loc env <> colon) $$ nest 2 msg
1156 ; liftIO (printErrs (full_msg defaultErrStyle))
1159 --------------------
1160 forkM_maybe :: SDoc -> IfL a -> IfL (Maybe a)
1161 -- Run thing_inside in an interleaved thread.
1162 -- It shares everything with the parent thread, so this is DANGEROUS.
1164 -- It returns Nothing if the computation fails
1166 -- It's used for lazily type-checking interface
1167 -- signatures, which is pretty benign
1169 forkM_maybe doc thing_inside
1170 = do { unsafeInterleaveM $
1171 do { traceIf (text "Starting fork {" <+> doc)
1173 updLclEnv (\env -> env { if_loc = if_loc env $$ doc }) $
1176 Right r -> do { traceIf (text "} ending fork" <+> doc)
1180 -- Bleat about errors in the forked thread, if -ddump-if-trace is on
1181 -- Otherwise we silently discard errors. Errors can legitimately
1182 -- happen when compiling interface signatures (see tcInterfaceSigs)
1183 ifDOptM Opt_D_dump_if_trace
1184 (print_errs (hang (text "forkM failed:" <+> doc)
1185 2 (text (show exn))))
1187 ; traceIf (text "} ending fork (badly)" <+> doc)
1191 print_errs sdoc = liftIO (printErrs (sdoc defaultErrStyle))
1193 forkM :: SDoc -> IfL a -> IfL a
1194 forkM doc thing_inside
1195 = do { mb_res <- forkM_maybe doc thing_inside
1196 ; return (case mb_res of
1197 Nothing -> pgmError "Cannot continue after interface file error"
1198 -- pprPanic "forkM" doc