2 % (c) The University of Glasgow 2006
7 -- The above warning supression flag is a temporary kludge.
8 -- While working on this module you are encouraged to remove it and fix
9 -- any warnings in the module. See
10 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
19 #include "HsVersions.h"
21 import TcRnTypes -- Re-export all
22 import IOEnv -- Re-export all
24 import HsSyn hiding (LIE)
55 import Control.Exception
61 %************************************************************************
65 %************************************************************************
71 -> Bool -- True <=> retain renamed syntax trees
74 -> IO (Messages, Maybe r)
75 -- Nothing => error thrown by the thing inside
76 -- (error messages should have been printed already)
78 initTc hsc_env hsc_src keep_rn_syntax mod do_this
79 = do { errs_var <- newIORef (emptyBag, emptyBag) ;
80 tvs_var <- newIORef emptyVarSet ;
81 type_env_var <- newIORef emptyNameEnv ;
82 dfuns_var <- newIORef emptyNameSet ;
83 keep_var <- newIORef emptyNameSet ;
84 th_var <- newIORef False ;
85 dfun_n_var <- newIORef 1 ;
87 maybe_rn_syntax empty_val
88 | keep_rn_syntax = Just empty_val
89 | otherwise = Nothing ;
94 tcg_rdr_env = hsc_global_rdr_env hsc_env,
95 tcg_fix_env = emptyNameEnv,
96 tcg_field_env = emptyNameEnv,
97 tcg_default = Nothing,
98 tcg_type_env = hsc_global_type_env hsc_env,
99 tcg_type_env_var = type_env_var,
100 tcg_inst_env = emptyInstEnv,
101 tcg_fam_inst_env = emptyFamInstEnv,
102 tcg_inst_uses = dfuns_var,
103 tcg_th_used = th_var,
105 tcg_imports = emptyImportAvails,
108 tcg_rn_imports = maybe_rn_syntax [],
109 tcg_rn_exports = maybe_rn_syntax [],
110 tcg_rn_decls = maybe_rn_syntax emptyRnGroup,
112 tcg_binds = emptyLHsBinds,
113 tcg_deprecs = NoDeprecs,
118 tcg_dfun_n = dfun_n_var,
121 tcg_hmi = HaddockModInfo Nothing Nothing Nothing Nothing,
126 tcl_loc = mkGeneralSrcSpan FSLIT("Top level"),
128 tcl_rdr = emptyLocalRdrEnv,
129 tcl_th_ctxt = topStage,
130 tcl_arrow_ctxt = NoArrowCtxt,
131 tcl_env = emptyNameEnv,
132 tcl_tyvars = tvs_var,
133 tcl_lie = panic "initTc:LIE" -- LIE only valid inside a getLIE
137 -- OK, here's the business end!
138 maybe_res <- initTcRnIf 'a' hsc_env gbl_env lcl_env $
139 do { r <- tryM do_this
141 Right res -> return (Just res)
142 Left _ -> return Nothing } ;
144 -- Collect any error messages
145 msgs <- readIORef errs_var ;
147 let { dflags = hsc_dflags hsc_env
148 ; final_res | errorsFound dflags msgs = Nothing
149 | otherwise = maybe_res } ;
151 return (msgs, final_res)
154 initTcPrintErrors -- Used from the interactive loop only
159 initTcPrintErrors env mod todo = do
160 (msgs, res) <- initTc env HsSrcFile False mod todo
161 printErrorsAndWarnings (hsc_dflags env) msgs
165 %************************************************************************
169 %************************************************************************
173 initTcRnIf :: Char -- Tag for unique supply
178 initTcRnIf uniq_tag hsc_env gbl_env lcl_env thing_inside
179 = do { us <- mkSplitUniqSupply uniq_tag ;
180 ; us_var <- newIORef us ;
182 ; let { env = Env { env_top = hsc_env,
187 ; runIOEnv env thing_inside
191 %************************************************************************
195 %************************************************************************
198 getTopEnv :: TcRnIf gbl lcl HscEnv
199 getTopEnv = do { env <- getEnv; return (env_top env) }
201 getGblEnv :: TcRnIf gbl lcl gbl
202 getGblEnv = do { env <- getEnv; return (env_gbl env) }
204 updGblEnv :: (gbl -> gbl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
205 updGblEnv upd = updEnv (\ env@(Env { env_gbl = gbl }) ->
206 env { env_gbl = upd gbl })
208 setGblEnv :: gbl -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
209 setGblEnv gbl_env = updEnv (\ env -> env { env_gbl = gbl_env })
211 getLclEnv :: TcRnIf gbl lcl lcl
212 getLclEnv = do { env <- getEnv; return (env_lcl env) }
214 updLclEnv :: (lcl -> lcl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
215 updLclEnv upd = updEnv (\ env@(Env { env_lcl = lcl }) ->
216 env { env_lcl = upd lcl })
218 setLclEnv :: lcl' -> TcRnIf gbl lcl' a -> TcRnIf gbl lcl a
219 setLclEnv lcl_env = updEnv (\ env -> env { env_lcl = lcl_env })
221 getEnvs :: TcRnIf gbl lcl (gbl, lcl)
222 getEnvs = do { env <- getEnv; return (env_gbl env, env_lcl env) }
224 setEnvs :: (gbl', lcl') -> TcRnIf gbl' lcl' a -> TcRnIf gbl lcl a
225 setEnvs (gbl_env, lcl_env) = updEnv (\ env -> env { env_gbl = gbl_env, env_lcl = lcl_env })
232 getDOpts :: TcRnIf gbl lcl DynFlags
233 getDOpts = do { env <- getTopEnv; return (hsc_dflags env) }
235 doptM :: DynFlag -> TcRnIf gbl lcl Bool
236 doptM flag = do { dflags <- getDOpts; return (dopt flag dflags) }
238 setOptM :: DynFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
239 setOptM flag = updEnv (\ env@(Env { env_top = top }) ->
240 env { env_top = top { hsc_dflags = dopt_set (hsc_dflags top) flag}} )
242 unsetOptM :: DynFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
243 unsetOptM flag = updEnv (\ env@(Env { env_top = top }) ->
244 env { env_top = top { hsc_dflags = dopt_unset (hsc_dflags top) flag}} )
246 -- | Do it flag is true
247 ifOptM :: DynFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl ()
248 ifOptM flag thing_inside = do { b <- doptM flag;
249 if b then thing_inside else return () }
251 getGhcMode :: TcRnIf gbl lcl GhcMode
252 getGhcMode = do { env <- getTopEnv; return (ghcMode (hsc_dflags env)) }
256 getEpsVar :: TcRnIf gbl lcl (TcRef ExternalPackageState)
257 getEpsVar = do { env <- getTopEnv; return (hsc_EPS env) }
259 getEps :: TcRnIf gbl lcl ExternalPackageState
260 getEps = do { env <- getTopEnv; readMutVar (hsc_EPS env) }
262 -- Updating the EPS. This should be an atomic operation.
263 -- Note the delicate 'seq' which forces the EPS before putting it in the
264 -- variable. Otherwise what happens is that we get
265 -- write eps_var (....(unsafeRead eps_var)....)
266 -- and if the .... is strict, that's obviously bottom. By forcing it beforehand
267 -- we make the unsafeRead happen before we update the variable.
269 updateEps :: (ExternalPackageState -> (ExternalPackageState, a))
271 updateEps upd_fn = do { traceIf (text "updating EPS")
272 ; eps_var <- getEpsVar
273 ; eps <- readMutVar eps_var
274 ; let { (eps', val) = upd_fn eps }
275 ; seq eps' (writeMutVar eps_var eps')
278 updateEps_ :: (ExternalPackageState -> ExternalPackageState)
280 updateEps_ upd_fn = do { traceIf (text "updating EPS_")
281 ; eps_var <- getEpsVar
282 ; eps <- readMutVar eps_var
283 ; let { eps' = upd_fn eps }
284 ; seq eps' (writeMutVar eps_var eps') }
286 getHpt :: TcRnIf gbl lcl HomePackageTable
287 getHpt = do { env <- getTopEnv; return (hsc_HPT env) }
289 getEpsAndHpt :: TcRnIf gbl lcl (ExternalPackageState, HomePackageTable)
290 getEpsAndHpt = do { env <- getTopEnv; eps <- readMutVar (hsc_EPS env)
291 ; return (eps, hsc_HPT env) }
294 %************************************************************************
298 %************************************************************************
301 newUnique :: TcRnIf gbl lcl Unique
303 = do { env <- getEnv ;
304 let { u_var = env_us env } ;
305 us <- readMutVar u_var ;
306 case splitUniqSupply us of { (us1,_) -> do {
307 writeMutVar u_var us1 ;
308 return $! uniqFromSupply us }}}
309 -- NOTE 1: we strictly split the supply, to avoid the possibility of leaving
310 -- a chain of unevaluated supplies behind.
311 -- NOTE 2: we use the uniq in the supply from the MutVar directly, and
312 -- throw away one half of the new split supply. This is safe because this
313 -- is the only place we use that unique. Using the other half of the split
314 -- supply is safer, but slower.
316 newUniqueSupply :: TcRnIf gbl lcl UniqSupply
318 = do { env <- getEnv ;
319 let { u_var = env_us env } ;
320 us <- readMutVar u_var ;
321 case splitUniqSupply us of { (us1,us2) -> do {
322 writeMutVar u_var us1 ;
325 newLocalName :: Name -> TcRnIf gbl lcl Name
326 newLocalName name -- Make a clone
327 = do { uniq <- newUnique
328 ; return (mkInternalName uniq (nameOccName name) (getSrcSpan name)) }
330 newSysLocalIds :: FastString -> [TcType] -> TcRnIf gbl lcl [TcId]
331 newSysLocalIds fs tys
332 = do { us <- newUniqueSupply
333 ; return (zipWith (mkSysLocal fs) (uniqsFromSupply us) tys) }
337 %************************************************************************
341 %************************************************************************
344 traceTc, traceRn :: SDoc -> TcRn ()
345 traceRn = traceOptTcRn Opt_D_dump_rn_trace
346 traceTc = traceOptTcRn Opt_D_dump_tc_trace
347 traceSplice = traceOptTcRn Opt_D_dump_splices
350 traceIf :: SDoc -> TcRnIf m n ()
351 traceIf = traceOptIf Opt_D_dump_if_trace
352 traceHiDiffs = traceOptIf Opt_D_dump_hi_diffs
355 traceOptIf :: DynFlag -> SDoc -> TcRnIf m n () -- No RdrEnv available, so qualify everything
356 traceOptIf flag doc = ifOptM flag $
357 liftIO (printForUser stderr alwaysQualify doc)
359 traceOptTcRn :: DynFlag -> SDoc -> TcRn ()
360 traceOptTcRn flag doc = ifOptM flag $ do
363 ; env0 <- tcInitTidyEnv
364 ; ctxt_msgs <- do_ctxt env0 ctxt
365 ; let real_doc = mkLocMessage loc (vcat (doc : ctxt_to_use ctxt_msgs))
366 ; dumpTcRn real_doc }
368 dumpTcRn :: SDoc -> TcRn ()
369 dumpTcRn doc = do { rdr_env <- getGlobalRdrEnv ;
371 liftIO (printForUser stderr (mkPrintUnqualified dflags rdr_env) doc) }
373 dumpOptTcRn :: DynFlag -> SDoc -> TcRn ()
374 dumpOptTcRn flag doc = ifOptM flag (dumpTcRn doc)
378 %************************************************************************
380 Typechecker global environment
382 %************************************************************************
385 getModule :: TcRn Module
386 getModule = do { env <- getGblEnv; return (tcg_mod env) }
388 setModule :: Module -> TcRn a -> TcRn a
389 setModule mod thing_inside = updGblEnv (\env -> env { tcg_mod = mod }) thing_inside
391 tcIsHsBoot :: TcRn Bool
392 tcIsHsBoot = do { env <- getGblEnv; return (isHsBoot (tcg_src env)) }
394 getGlobalRdrEnv :: TcRn GlobalRdrEnv
395 getGlobalRdrEnv = do { env <- getGblEnv; return (tcg_rdr_env env) }
397 getRdrEnvs :: TcRn (GlobalRdrEnv, LocalRdrEnv)
398 getRdrEnvs = do { (gbl,lcl) <- getEnvs; return (tcg_rdr_env gbl, tcl_rdr lcl) }
400 getImports :: TcRn ImportAvails
401 getImports = do { env <- getGblEnv; return (tcg_imports env) }
403 getFixityEnv :: TcRn FixityEnv
404 getFixityEnv = do { env <- getGblEnv; return (tcg_fix_env env) }
406 extendFixityEnv :: [(Name,FixItem)] -> RnM a -> RnM a
407 extendFixityEnv new_bit
408 = updGblEnv (\env@(TcGblEnv { tcg_fix_env = old_fix_env }) ->
409 env {tcg_fix_env = extendNameEnvList old_fix_env new_bit})
411 getRecFieldEnv :: TcRn RecFieldEnv
412 getRecFieldEnv = do { env <- getGblEnv; return (tcg_field_env env) }
414 extendRecFieldEnv :: RecFieldEnv -> RnM a -> RnM a
415 extendRecFieldEnv new_bit
416 = updGblEnv (\env@(TcGblEnv { tcg_field_env = old_env }) ->
417 env {tcg_field_env = old_env `plusNameEnv` new_bit})
419 getDeclaredDefaultTys :: TcRn (Maybe [Type])
420 getDeclaredDefaultTys = do { env <- getGblEnv; return (tcg_default env) }
423 %************************************************************************
427 %************************************************************************
430 getSrcSpanM :: TcRn SrcSpan
431 -- Avoid clash with Name.getSrcLoc
432 getSrcSpanM = do { env <- getLclEnv; return (tcl_loc env) }
434 setSrcSpan :: SrcSpan -> TcRn a -> TcRn a
435 setSrcSpan loc thing_inside
436 | isGoodSrcSpan loc = updLclEnv (\env -> env { tcl_loc = loc }) thing_inside
437 | otherwise = thing_inside -- Don't overwrite useful info with useless
439 addLocM :: (a -> TcM b) -> Located a -> TcM b
440 addLocM fn (L loc a) = setSrcSpan loc $ fn a
442 wrapLocM :: (a -> TcM b) -> Located a -> TcM (Located b)
443 wrapLocM fn (L loc a) = setSrcSpan loc $ do b <- fn a; return (L loc b)
445 wrapLocFstM :: (a -> TcM (b,c)) -> Located a -> TcM (Located b, c)
446 wrapLocFstM fn (L loc a) =
451 wrapLocSndM :: (a -> TcM (b,c)) -> Located a -> TcM (b, Located c)
452 wrapLocSndM fn (L loc a) =
460 getErrsVar :: TcRn (TcRef Messages)
461 getErrsVar = do { env <- getLclEnv; return (tcl_errs env) }
463 setErrsVar :: TcRef Messages -> TcRn a -> TcRn a
464 setErrsVar v = updLclEnv (\ env -> env { tcl_errs = v })
466 addErr :: Message -> TcRn ()
467 addErr msg = do { loc <- getSrcSpanM ; addErrAt loc msg }
469 addLocErr :: Located e -> (e -> Message) -> TcRn ()
470 addLocErr (L loc e) fn = addErrAt loc (fn e)
472 addErrAt :: SrcSpan -> Message -> TcRn ()
473 addErrAt loc msg = addLongErrAt loc msg empty
475 addLongErrAt :: SrcSpan -> Message -> Message -> TcRn ()
476 addLongErrAt loc msg extra
477 = do { traceTc (ptext SLIT("Adding error:") <+> (mkLocMessage loc (msg $$ extra))) ;
478 errs_var <- getErrsVar ;
479 rdr_env <- getGlobalRdrEnv ;
481 let { err = mkLongErrMsg loc (mkPrintUnqualified dflags rdr_env) msg extra } ;
482 (warns, errs) <- readMutVar errs_var ;
483 writeMutVar errs_var (warns, errs `snocBag` err) }
485 addErrs :: [(SrcSpan,Message)] -> TcRn ()
486 addErrs msgs = mapM_ add msgs
488 add (loc,msg) = addErrAt loc msg
490 addReport :: Message -> TcRn ()
491 addReport msg = do loc <- getSrcSpanM; addReportAt loc msg
493 addReportAt :: SrcSpan -> Message -> TcRn ()
495 = do { errs_var <- getErrsVar ;
496 rdr_env <- getGlobalRdrEnv ;
498 let { warn = mkWarnMsg loc (mkPrintUnqualified dflags rdr_env) msg } ;
499 (warns, errs) <- readMutVar errs_var ;
500 writeMutVar errs_var (warns `snocBag` warn, errs) }
502 addWarn :: Message -> TcRn ()
503 addWarn msg = addReport (ptext SLIT("Warning:") <+> msg)
505 addWarnAt :: SrcSpan -> Message -> TcRn ()
506 addWarnAt loc msg = addReportAt loc (ptext SLIT("Warning:") <+> msg)
508 addLocWarn :: Located e -> (e -> Message) -> TcRn ()
509 addLocWarn (L loc e) fn = addReportAt loc (fn e)
511 checkErr :: Bool -> Message -> TcRn ()
512 -- Add the error if the bool is False
513 checkErr ok msg = unless ok (addErr msg)
515 warnIf :: Bool -> Message -> TcRn ()
516 warnIf True msg = addWarn msg
517 warnIf False msg = return ()
519 addMessages :: Messages -> TcRn ()
520 addMessages (m_warns, m_errs)
521 = do { errs_var <- getErrsVar ;
522 (warns, errs) <- readMutVar errs_var ;
523 writeMutVar errs_var (warns `unionBags` m_warns,
524 errs `unionBags` m_errs) }
526 discardWarnings :: TcRn a -> TcRn a
527 -- Ignore warnings inside the thing inside;
528 -- used to ignore-unused-variable warnings inside derived code
529 -- With -dppr-debug, the effects is switched off, so you can still see
530 -- what warnings derived code would give
531 discardWarnings thing_inside
532 | opt_PprStyle_Debug = thing_inside
534 = do { errs_var <- newMutVar emptyMessages
535 ; result <- setErrsVar errs_var thing_inside
536 ; (_warns, errs) <- readMutVar errs_var
537 ; addMessages (emptyBag, errs)
543 try_m :: TcRn r -> TcRn (Either Exception r)
544 -- Does try_m, with a debug-trace on failure
546 = do { mb_r <- tryM thing ;
548 Left exn -> do { traceTc (exn_msg exn); return mb_r }
549 Right r -> return mb_r }
551 exn_msg exn = text "tryTc/recoverM recovering from" <+> text (showException exn)
553 -----------------------
554 recoverM :: TcRn r -- Recovery action; do this if the main one fails
555 -> TcRn r -- Main action: do this first
557 -- Errors in 'thing' are retained
558 recoverM recover thing
559 = do { mb_res <- try_m thing ;
562 Right res -> return res }
565 -----------------------
566 mapAndRecoverM :: (a -> TcRn b) -> [a] -> TcRn [b]
567 -- Drop elements of the input that fail, so the result
568 -- list can be shorter than the argument list
569 mapAndRecoverM f [] = return []
570 mapAndRecoverM f (x:xs) = do { mb_r <- tryM (f x)
571 ; rs <- mapAndRecoverM f xs
572 ; return (case mb_r of
577 -----------------------
578 tryTc :: TcRn a -> TcRn (Messages, Maybe a)
579 -- (tryTc m) executes m, and returns
580 -- Just r, if m succeeds (returning r)
581 -- Nothing, if m fails
582 -- It also returns all the errors and warnings accumulated by m
583 -- It always succeeds (never raises an exception)
585 = do { errs_var <- newMutVar emptyMessages ;
586 res <- try_m (setErrsVar errs_var m) ;
587 msgs <- readMutVar errs_var ;
588 return (msgs, case res of
590 Right val -> Just val)
591 -- The exception is always the IOEnv built-in
592 -- in exception; see IOEnv.failM
595 -----------------------
596 tryTcErrs :: TcRn a -> TcRn (Messages, Maybe a)
597 -- Run the thing, returning
598 -- Just r, if m succceeds with no error messages
599 -- Nothing, if m fails, or if it succeeds but has error messages
600 -- Either way, the messages are returned; even in the Just case
601 -- there might be warnings
603 = do { (msgs, res) <- tryTc thing
605 ; let errs_found = errorsFound dflags msgs
606 ; return (msgs, case res of
608 Just val | errs_found -> Nothing
609 | otherwise -> Just val)
612 -----------------------
613 tryTcLIE :: TcM a -> TcM (Messages, Maybe a)
614 -- Just like tryTcErrs, except that it ensures that the LIE
615 -- for the thing is propagated only if there are no errors
616 -- Hence it's restricted to the type-check monad
617 tryTcLIE thing_inside
618 = do { ((msgs, mb_res), lie) <- getLIE (tryTcErrs thing_inside) ;
620 Nothing -> return (msgs, Nothing)
621 Just val -> do { extendLIEs lie; return (msgs, Just val) }
624 -----------------------
625 tryTcLIE_ :: TcM r -> TcM r -> TcM r
626 -- (tryTcLIE_ r m) tries m;
627 -- if m succeeds with no error messages, it's the answer
628 -- otherwise tryTcLIE_ drops everything from m and tries r instead.
629 tryTcLIE_ recover main
630 = do { (msgs, mb_res) <- tryTcLIE main
632 Just val -> do { addMessages msgs -- There might be warnings
634 Nothing -> recover -- Discard all msgs
637 -----------------------
638 checkNoErrs :: TcM r -> TcM r
639 -- (checkNoErrs m) succeeds iff m succeeds and generates no errors
640 -- If m fails then (checkNoErrsTc m) fails.
641 -- If m succeeds, it checks whether m generated any errors messages
642 -- (it might have recovered internally)
643 -- If so, it fails too.
644 -- Regardless, any errors generated by m are propagated to the enclosing context.
646 = do { (msgs, mb_res) <- tryTcLIE main
650 Just val -> return val
653 ifErrsM :: TcRn r -> TcRn r -> TcRn r
654 -- ifErrsM bale_out main
655 -- does 'bale_out' if there are errors in errors collection
656 -- otherwise does 'main'
657 ifErrsM bale_out normal
658 = do { errs_var <- getErrsVar ;
659 msgs <- readMutVar errs_var ;
661 if errorsFound dflags msgs then
666 failIfErrsM :: TcRn ()
667 -- Useful to avoid error cascades
668 failIfErrsM = ifErrsM failM (return ())
672 %************************************************************************
674 Context management and error message generation
677 %************************************************************************
680 getErrCtxt :: TcM ErrCtxt
681 getErrCtxt = do { env <- getLclEnv; return (tcl_ctxt env) }
683 setErrCtxt :: ErrCtxt -> TcM a -> TcM a
684 setErrCtxt ctxt = updLclEnv (\ env -> env { tcl_ctxt = ctxt })
686 addErrCtxt :: Message -> TcM a -> TcM a
687 addErrCtxt msg = addErrCtxtM (\env -> return (env, msg))
689 addErrCtxtM :: (TidyEnv -> TcM (TidyEnv, Message)) -> TcM a -> TcM a
690 addErrCtxtM msg = updCtxt (\ msgs -> msg : msgs)
692 -- Helper function for the above
693 updCtxt :: (ErrCtxt -> ErrCtxt) -> TcM a -> TcM a
694 updCtxt upd = updLclEnv (\ env@(TcLclEnv { tcl_ctxt = ctxt }) ->
695 env { tcl_ctxt = upd ctxt })
697 -- Conditionally add an error context
698 maybeAddErrCtxt :: Maybe Message -> TcM a -> TcM a
699 maybeAddErrCtxt (Just msg) thing_inside = addErrCtxt msg thing_inside
700 maybeAddErrCtxt Nothing thing_inside = thing_inside
702 popErrCtxt :: TcM a -> TcM a
703 popErrCtxt = updCtxt (\ msgs -> case msgs of { [] -> []; (m:ms) -> ms })
705 getInstLoc :: InstOrigin -> TcM InstLoc
707 = do { loc <- getSrcSpanM ; env <- getLclEnv ;
708 return (InstLoc origin loc (tcl_ctxt env)) }
710 addInstCtxt :: InstLoc -> TcM a -> TcM a
711 -- Add the SrcSpan and context from the first Inst in the list
712 -- (they all have similar locations)
713 addInstCtxt (InstLoc _ src_loc ctxt) thing_inside
714 = setSrcSpan src_loc (updCtxt (\ old_ctxt -> ctxt) thing_inside)
717 The addErrTc functions add an error message, but do not cause failure.
718 The 'M' variants pass a TidyEnv that has already been used to
719 tidy up the message; we then use it to tidy the context messages
722 addErrTc :: Message -> TcM ()
723 addErrTc err_msg = do { env0 <- tcInitTidyEnv
724 ; addErrTcM (env0, err_msg) }
726 addErrsTc :: [Message] -> TcM ()
727 addErrsTc err_msgs = mapM_ addErrTc err_msgs
729 addErrTcM :: (TidyEnv, Message) -> TcM ()
730 addErrTcM (tidy_env, err_msg)
731 = do { ctxt <- getErrCtxt ;
733 add_err_tcm tidy_env err_msg loc ctxt }
736 The failWith functions add an error message and cause failure
739 failWithTc :: Message -> TcM a -- Add an error message and fail
741 = addErrTc err_msg >> failM
743 failWithTcM :: (TidyEnv, Message) -> TcM a -- Add an error message and fail
744 failWithTcM local_and_msg
745 = addErrTcM local_and_msg >> failM
747 checkTc :: Bool -> Message -> TcM () -- Check that the boolean is true
748 checkTc True err = return ()
749 checkTc False err = failWithTc err
752 Warnings have no 'M' variant, nor failure
755 addWarnTc :: Message -> TcM ()
756 addWarnTc msg = do { env0 <- tcInitTidyEnv
757 ; addWarnTcM (env0, msg) }
759 addWarnTcM :: (TidyEnv, Message) -> TcM ()
760 addWarnTcM (env0, msg)
761 = do { ctxt <- getErrCtxt ;
762 ctxt_msgs <- do_ctxt env0 ctxt ;
763 addReport (vcat (ptext SLIT("Warning:") <+> msg : ctxt_to_use ctxt_msgs)) }
765 warnTc :: Bool -> Message -> TcM ()
766 warnTc warn_if_true warn_msg
767 | warn_if_true = addWarnTc warn_msg
768 | otherwise = return ()
771 -----------------------------------
774 We initialise the "tidy-env", used for tidying types before printing,
775 by building a reverse map from the in-scope type variables to the
776 OccName that the programmer originally used for them
779 tcInitTidyEnv :: TcM TidyEnv
781 = do { lcl_env <- getLclEnv
782 ; let nm_tv_prs = [ (name, tcGetTyVar "tcInitTidyEnv" ty)
783 | ATyVar name ty <- nameEnvElts (tcl_env lcl_env)
785 ; return (foldl add emptyTidyEnv nm_tv_prs) }
787 add (env,subst) (name, tyvar)
788 = case tidyOccName env (nameOccName name) of
789 (env', occ') -> (env', extendVarEnv subst tyvar tyvar')
791 tyvar' = setTyVarName tyvar name'
792 name' = tidyNameOcc name occ'
795 -----------------------------------
796 Other helper functions
799 add_err_tcm tidy_env err_msg loc ctxt
800 = do { ctxt_msgs <- do_ctxt tidy_env ctxt ;
801 addLongErrAt loc err_msg (vcat (ctxt_to_use ctxt_msgs)) }
805 do_ctxt tidy_env (c:cs)
806 = do { (tidy_env', m) <- c tidy_env ;
807 ms <- do_ctxt tidy_env' cs ;
810 ctxt_to_use ctxt | opt_PprStyle_Debug = ctxt
811 | otherwise = take 3 ctxt
814 debugTc is useful for monadic debugging code
817 debugTc :: TcM () -> TcM ()
819 debugTc thing = thing
821 debugTc thing = return ()
825 %************************************************************************
827 Type constraints (the so-called LIE)
829 %************************************************************************
832 nextDFunIndex :: TcM Int -- Get the next dfun index
833 nextDFunIndex = do { env <- getGblEnv
834 ; let dfun_n_var = tcg_dfun_n env
835 ; n <- readMutVar dfun_n_var
836 ; writeMutVar dfun_n_var (n+1)
839 getLIEVar :: TcM (TcRef LIE)
840 getLIEVar = do { env <- getLclEnv; return (tcl_lie env) }
842 setLIEVar :: TcRef LIE -> TcM a -> TcM a
843 setLIEVar lie_var = updLclEnv (\ env -> env { tcl_lie = lie_var })
845 getLIE :: TcM a -> TcM (a, [Inst])
846 -- (getLIE m) runs m, and returns the type constraints it generates
848 = do { lie_var <- newMutVar emptyLIE ;
849 res <- updLclEnv (\ env -> env { tcl_lie = lie_var })
851 lie <- readMutVar lie_var ;
852 return (res, lieToList lie) }
854 extendLIE :: Inst -> TcM ()
856 = do { lie_var <- getLIEVar ;
857 lie <- readMutVar lie_var ;
858 writeMutVar lie_var (inst `consLIE` lie) }
860 extendLIEs :: [Inst] -> TcM ()
864 = do { lie_var <- getLIEVar ;
865 lie <- readMutVar lie_var ;
866 writeMutVar lie_var (mkLIE insts `plusLIE` lie) }
870 setLclTypeEnv :: TcLclEnv -> TcM a -> TcM a
871 -- Set the local type envt, but do *not* disturb other fields,
872 -- notably the lie_var
873 setLclTypeEnv lcl_env thing_inside
874 = updLclEnv upd thing_inside
876 upd env = env { tcl_env = tcl_env lcl_env,
877 tcl_tyvars = tcl_tyvars lcl_env }
881 %************************************************************************
883 Template Haskell context
885 %************************************************************************
888 recordThUse :: TcM ()
889 recordThUse = do { env <- getGblEnv; writeMutVar (tcg_th_used env) True }
891 keepAliveTc :: Id -> TcM () -- Record the name in the keep-alive set
893 | isLocalId id = do { env <- getGblEnv;
894 ; updMutVar (tcg_keep env) (`addOneToNameSet` idName id) }
895 | otherwise = return ()
897 keepAliveSetTc :: NameSet -> TcM () -- Record the name in the keep-alive set
898 keepAliveSetTc ns = do { env <- getGblEnv;
899 ; updMutVar (tcg_keep env) (`unionNameSets` ns) }
901 getStage :: TcM ThStage
902 getStage = do { env <- getLclEnv; return (tcl_th_ctxt env) }
904 setStage :: ThStage -> TcM a -> TcM a
905 setStage s = updLclEnv (\ env -> env { tcl_th_ctxt = s })
909 %************************************************************************
911 Stuff for the renamer's local env
913 %************************************************************************
916 getLocalRdrEnv :: RnM LocalRdrEnv
917 getLocalRdrEnv = do { env <- getLclEnv; return (tcl_rdr env) }
919 setLocalRdrEnv :: LocalRdrEnv -> RnM a -> RnM a
920 setLocalRdrEnv rdr_env thing_inside
921 = updLclEnv (\env -> env {tcl_rdr = rdr_env}) thing_inside
925 %************************************************************************
927 Stuff for interface decls
929 %************************************************************************
932 mkIfLclEnv :: Module -> SDoc -> IfLclEnv
933 mkIfLclEnv mod loc = IfLclEnv { if_mod = mod,
935 if_tv_env = emptyUFM,
936 if_id_env = emptyUFM }
938 initIfaceTcRn :: IfG a -> TcRn a
939 initIfaceTcRn thing_inside
940 = do { tcg_env <- getGblEnv
941 ; let { if_env = IfGblEnv { if_rec_types = Just (tcg_mod tcg_env, get_type_env) }
942 ; get_type_env = readMutVar (tcg_type_env_var tcg_env) }
943 ; setEnvs (if_env, ()) thing_inside }
945 initIfaceExtCore :: IfL a -> TcRn a
946 initIfaceExtCore thing_inside
947 = do { tcg_env <- getGblEnv
948 ; let { mod = tcg_mod tcg_env
949 ; doc = ptext SLIT("External Core file for") <+> quotes (ppr mod)
950 ; if_env = IfGblEnv {
951 if_rec_types = Just (mod, return (tcg_type_env tcg_env)) }
952 ; if_lenv = mkIfLclEnv mod doc
954 ; setEnvs (if_env, if_lenv) thing_inside }
956 initIfaceCheck :: HscEnv -> IfG a -> IO a
957 -- Used when checking the up-to-date-ness of the old Iface
958 -- Initialise the environment with no useful info at all
959 initIfaceCheck hsc_env do_this
960 = do { let gbl_env = IfGblEnv { if_rec_types = Nothing }
961 ; initTcRnIf 'i' hsc_env gbl_env () do_this
964 initIfaceTc :: ModIface
965 -> (TcRef TypeEnv -> IfL a) -> TcRnIf gbl lcl a
966 -- Used when type-checking checking an up-to-date interface file
967 -- No type envt from the current module, but we do know the module dependencies
968 initIfaceTc iface do_this
969 = do { tc_env_var <- newMutVar emptyTypeEnv
970 ; let { gbl_env = IfGblEnv { if_rec_types = Just (mod, readMutVar tc_env_var) } ;
971 ; if_lenv = mkIfLclEnv mod doc
973 ; setEnvs (gbl_env, if_lenv) (do_this tc_env_var)
976 mod = mi_module iface
977 doc = ptext SLIT("The interface for") <+> quotes (ppr mod)
979 initIfaceRules :: HscEnv -> ModGuts -> IfG a -> IO a
980 -- Used when sucking in new Rules in SimplCore
981 -- We have available the type envt of the module being compiled, and we must use it
982 initIfaceRules hsc_env guts do_this
984 type_info = (mg_module guts, return (mg_types guts))
985 ; gbl_env = IfGblEnv { if_rec_types = Just type_info } ;
988 -- Run the thing; any exceptions just bubble out from here
989 ; initTcRnIf 'i' hsc_env gbl_env () do_this
992 initIfaceLcl :: Module -> SDoc -> IfL a -> IfM lcl a
993 initIfaceLcl mod loc_doc thing_inside
994 = setLclEnv (mkIfLclEnv mod loc_doc) thing_inside
996 getIfModule :: IfL Module
997 getIfModule = do { env <- getLclEnv; return (if_mod env) }
1000 failIfM :: Message -> IfL a
1001 -- The Iface monad doesn't have a place to accumulate errors, so we
1002 -- just fall over fast if one happens; it "shouldnt happen".
1003 -- We use IfL here so that we can get context info out of the local env
1005 = do { env <- getLclEnv
1006 ; let full_msg = (if_loc env <> colon) $$ nest 2 msg
1007 ; liftIO (printErrs (full_msg defaultErrStyle))
1010 --------------------
1011 forkM_maybe :: SDoc -> IfL a -> IfL (Maybe a)
1012 -- Run thing_inside in an interleaved thread.
1013 -- It shares everything with the parent thread, so this is DANGEROUS.
1015 -- It returns Nothing if the computation fails
1017 -- It's used for lazily type-checking interface
1018 -- signatures, which is pretty benign
1020 forkM_maybe doc thing_inside
1021 = do { unsafeInterleaveM $
1022 do { traceIf (text "Starting fork {" <+> doc)
1024 updLclEnv (\env -> env { if_loc = if_loc env $$ doc }) $
1027 Right r -> do { traceIf (text "} ending fork" <+> doc)
1031 -- Bleat about errors in the forked thread, if -ddump-if-trace is on
1032 -- Otherwise we silently discard errors. Errors can legitimately
1033 -- happen when compiling interface signatures (see tcInterfaceSigs)
1034 ifOptM Opt_D_dump_if_trace
1035 (print_errs (hang (text "forkM failed:" <+> doc)
1036 4 (text (show exn))))
1038 ; traceIf (text "} ending fork (badly)" <+> doc)
1042 print_errs sdoc = liftIO (printErrs (sdoc defaultErrStyle))
1044 forkM :: SDoc -> IfL a -> IfL a
1045 forkM doc thing_inside
1046 = do { mb_res <- forkM_maybe doc thing_inside
1047 ; return (case mb_res of
1048 Nothing -> pgmError "Cannot continue after interface file error"
1049 -- pprPanic "forkM" doc