2 % (c) The University of Glasgow 2006
12 import TcRnTypes -- Re-export all
13 import IOEnv -- Re-export all
15 import HsSyn hiding (LIE)
52 %************************************************************************
56 %************************************************************************
62 -> Bool -- True <=> retain renamed syntax trees
65 -> IO (Messages, Maybe r)
66 -- Nothing => error thrown by the thing inside
67 -- (error messages should have been printed already)
69 initTc hsc_env hsc_src keep_rn_syntax mod do_this
70 = do { errs_var <- newIORef (emptyBag, emptyBag) ;
71 tvs_var <- newIORef emptyVarSet ;
72 dfuns_var <- newIORef emptyNameSet ;
73 keep_var <- newIORef emptyNameSet ;
74 th_var <- newIORef False ;
75 dfun_n_var <- newIORef 1 ;
76 type_env_var <- case hsc_type_env_var hsc_env of {
77 Just (_mod, te_var) -> return te_var ;
78 Nothing -> newIORef emptyNameEnv } ;
80 maybe_rn_syntax empty_val
81 | keep_rn_syntax = Just empty_val
82 | otherwise = Nothing ;
87 tcg_rdr_env = hsc_global_rdr_env hsc_env,
88 tcg_fix_env = emptyNameEnv,
89 tcg_field_env = emptyNameEnv,
90 tcg_default = Nothing,
91 tcg_type_env = hsc_global_type_env hsc_env,
92 tcg_type_env_var = type_env_var,
93 tcg_inst_env = emptyInstEnv,
94 tcg_fam_inst_env = emptyFamInstEnv,
95 tcg_inst_uses = dfuns_var,
98 tcg_imports = emptyImportAvails,
101 tcg_rn_imports = maybe_rn_syntax [],
102 tcg_rn_exports = maybe_rn_syntax [],
103 tcg_rn_decls = maybe_rn_syntax emptyRnGroup,
105 tcg_binds = emptyLHsBinds,
106 tcg_warns = NoWarnings,
111 tcg_dfun_n = dfun_n_var,
114 tcg_hmi = HaddockModInfo Nothing Nothing Nothing Nothing,
119 tcl_loc = mkGeneralSrcSpan (fsLit "Top level"),
121 tcl_rdr = emptyLocalRdrEnv,
122 tcl_th_ctxt = topStage,
123 tcl_arrow_ctxt = NoArrowCtxt,
124 tcl_env = emptyNameEnv,
125 tcl_tyvars = tvs_var,
126 tcl_lie = panic "initTc:LIE" -- LIE only valid inside a getLIE
130 -- OK, here's the business end!
131 maybe_res <- initTcRnIf 'a' hsc_env gbl_env lcl_env $
132 do { r <- tryM do_this
134 Right res -> return (Just res)
135 Left _ -> return Nothing } ;
137 -- Collect any error messages
138 msgs <- readIORef errs_var ;
140 let { dflags = hsc_dflags hsc_env
141 ; final_res | errorsFound dflags msgs = Nothing
142 | otherwise = maybe_res } ;
144 return (msgs, final_res)
147 initTcPrintErrors -- Used from the interactive loop only
151 -> IO (Messages, Maybe r)
152 initTcPrintErrors env mod todo = do
153 (msgs, res) <- initTc env HsSrcFile False mod todo
157 %************************************************************************
161 %************************************************************************
165 initTcRnIf :: Char -- Tag for unique supply
170 initTcRnIf uniq_tag hsc_env gbl_env lcl_env thing_inside
171 = do { us <- mkSplitUniqSupply uniq_tag ;
172 ; us_var <- newIORef us ;
174 ; let { env = Env { env_top = hsc_env,
179 ; runIOEnv env thing_inside
183 %************************************************************************
187 %************************************************************************
190 getTopEnv :: TcRnIf gbl lcl HscEnv
191 getTopEnv = do { env <- getEnv; return (env_top env) }
193 getGblEnv :: TcRnIf gbl lcl gbl
194 getGblEnv = do { env <- getEnv; return (env_gbl env) }
196 updGblEnv :: (gbl -> gbl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
197 updGblEnv upd = updEnv (\ env@(Env { env_gbl = gbl }) ->
198 env { env_gbl = upd gbl })
200 setGblEnv :: gbl -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
201 setGblEnv gbl_env = updEnv (\ env -> env { env_gbl = gbl_env })
203 getLclEnv :: TcRnIf gbl lcl lcl
204 getLclEnv = do { env <- getEnv; return (env_lcl env) }
206 updLclEnv :: (lcl -> lcl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
207 updLclEnv upd = updEnv (\ env@(Env { env_lcl = lcl }) ->
208 env { env_lcl = upd lcl })
210 setLclEnv :: lcl' -> TcRnIf gbl lcl' a -> TcRnIf gbl lcl a
211 setLclEnv lcl_env = updEnv (\ env -> env { env_lcl = lcl_env })
213 getEnvs :: TcRnIf gbl lcl (gbl, lcl)
214 getEnvs = do { env <- getEnv; return (env_gbl env, env_lcl env) }
216 setEnvs :: (gbl', lcl') -> TcRnIf gbl' lcl' a -> TcRnIf gbl lcl a
217 setEnvs (gbl_env, lcl_env) = updEnv (\ env -> env { env_gbl = gbl_env, env_lcl = lcl_env })
224 getDOpts :: TcRnIf gbl lcl DynFlags
225 getDOpts = do { env <- getTopEnv; return (hsc_dflags env) }
227 doptM :: DynFlag -> TcRnIf gbl lcl Bool
228 doptM flag = do { dflags <- getDOpts; return (dopt flag dflags) }
230 setOptM :: DynFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
231 setOptM flag = updEnv (\ env@(Env { env_top = top }) ->
232 env { env_top = top { hsc_dflags = dopt_set (hsc_dflags top) flag}} )
234 unsetOptM :: DynFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
235 unsetOptM flag = updEnv (\ env@(Env { env_top = top }) ->
236 env { env_top = top { hsc_dflags = dopt_unset (hsc_dflags top) flag}} )
238 -- | Do it flag is true
239 ifOptM :: DynFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl ()
240 ifOptM flag thing_inside = do { b <- doptM flag;
241 if b then thing_inside else return () }
243 getGhcMode :: TcRnIf gbl lcl GhcMode
244 getGhcMode = do { env <- getTopEnv; return (ghcMode (hsc_dflags env)) }
248 getEpsVar :: TcRnIf gbl lcl (TcRef ExternalPackageState)
249 getEpsVar = do { env <- getTopEnv; return (hsc_EPS env) }
251 getEps :: TcRnIf gbl lcl ExternalPackageState
252 getEps = do { env <- getTopEnv; readMutVar (hsc_EPS env) }
254 -- Updating the EPS. This should be an atomic operation.
255 -- Note the delicate 'seq' which forces the EPS before putting it in the
256 -- variable. Otherwise what happens is that we get
257 -- write eps_var (....(unsafeRead eps_var)....)
258 -- and if the .... is strict, that's obviously bottom. By forcing it beforehand
259 -- we make the unsafeRead happen before we update the variable.
261 updateEps :: (ExternalPackageState -> (ExternalPackageState, a))
263 updateEps upd_fn = do { traceIf (text "updating EPS")
264 ; eps_var <- getEpsVar
265 ; eps <- readMutVar eps_var
266 ; let { (eps', val) = upd_fn eps }
267 ; seq eps' (writeMutVar eps_var eps')
270 updateEps_ :: (ExternalPackageState -> ExternalPackageState)
272 updateEps_ upd_fn = do { traceIf (text "updating EPS_")
273 ; eps_var <- getEpsVar
274 ; eps <- readMutVar eps_var
275 ; let { eps' = upd_fn eps }
276 ; seq eps' (writeMutVar eps_var eps') }
278 getHpt :: TcRnIf gbl lcl HomePackageTable
279 getHpt = do { env <- getTopEnv; return (hsc_HPT env) }
281 getEpsAndHpt :: TcRnIf gbl lcl (ExternalPackageState, HomePackageTable)
282 getEpsAndHpt = do { env <- getTopEnv; eps <- readMutVar (hsc_EPS env)
283 ; return (eps, hsc_HPT env) }
286 %************************************************************************
290 %************************************************************************
293 newUnique :: TcRnIf gbl lcl Unique
295 = do { env <- getEnv ;
296 let { u_var = env_us env } ;
297 us <- readMutVar u_var ;
298 case splitUniqSupply us of { (us1,_) -> do {
299 writeMutVar u_var us1 ;
300 return $! uniqFromSupply us }}}
301 -- NOTE 1: we strictly split the supply, to avoid the possibility of leaving
302 -- a chain of unevaluated supplies behind.
303 -- NOTE 2: we use the uniq in the supply from the MutVar directly, and
304 -- throw away one half of the new split supply. This is safe because this
305 -- is the only place we use that unique. Using the other half of the split
306 -- supply is safer, but slower.
308 newUniqueSupply :: TcRnIf gbl lcl UniqSupply
310 = do { env <- getEnv ;
311 let { u_var = env_us env } ;
312 us <- readMutVar u_var ;
313 case splitUniqSupply us of { (us1,us2) -> do {
314 writeMutVar u_var us1 ;
317 newLocalName :: Name -> TcRnIf gbl lcl Name
318 newLocalName name -- Make a clone
319 = do { uniq <- newUnique
320 ; return (mkInternalName uniq (nameOccName name) (getSrcSpan name)) }
322 newSysLocalIds :: FastString -> [TcType] -> TcRnIf gbl lcl [TcId]
323 newSysLocalIds fs tys
324 = do { us <- newUniqueSupply
325 ; return (zipWith (mkSysLocal fs) (uniqsFromSupply us) tys) }
327 instance MonadUnique (IOEnv (Env gbl lcl)) where
328 getUniqueM = newUnique
329 getUniqueSupplyM = newUniqueSupply
333 %************************************************************************
337 %************************************************************************
340 traceTc, traceRn, traceSplice :: SDoc -> TcRn ()
341 traceRn = traceOptTcRn Opt_D_dump_rn_trace
342 traceTc = traceOptTcRn Opt_D_dump_tc_trace
343 traceSplice = traceOptTcRn Opt_D_dump_splices
346 traceIf, traceHiDiffs :: SDoc -> TcRnIf m n ()
347 traceIf = traceOptIf Opt_D_dump_if_trace
348 traceHiDiffs = traceOptIf Opt_D_dump_hi_diffs
351 traceOptIf :: DynFlag -> SDoc -> TcRnIf m n () -- No RdrEnv available, so qualify everything
352 traceOptIf flag doc = ifOptM flag $
353 liftIO (printForUser stderr alwaysQualify doc)
355 traceOptTcRn :: DynFlag -> SDoc -> TcRn ()
356 traceOptTcRn flag doc = ifOptM flag $ do
359 ; env0 <- tcInitTidyEnv
360 ; ctxt_msgs <- do_ctxt env0 ctxt
361 ; let real_doc = mkLocMessage loc (vcat (doc : ctxt_to_use ctxt_msgs))
362 ; dumpTcRn real_doc }
364 dumpTcRn :: SDoc -> TcRn ()
365 dumpTcRn doc = do { rdr_env <- getGlobalRdrEnv ;
367 liftIO (printForUser stderr (mkPrintUnqualified dflags rdr_env) doc) }
369 debugDumpTcRn :: SDoc -> TcRn ()
370 debugDumpTcRn doc | opt_NoDebugOutput = return ()
371 | otherwise = dumpTcRn 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 () -- Ignores the context stack
467 addErr msg = do { loc <- getSrcSpanM ; addErrAt loc msg }
469 failWith :: Message -> TcRn a
470 failWith msg = addErr msg >> failM
472 addLocErr :: Located e -> (e -> Message) -> TcRn ()
473 addLocErr (L loc e) fn = addErrAt loc (fn e)
475 addErrAt :: SrcSpan -> Message -> TcRn ()
476 addErrAt loc msg = addLongErrAt loc msg empty
478 addLongErrAt :: SrcSpan -> Message -> Message -> TcRn ()
479 addLongErrAt loc msg extra
480 = do { traceTc (ptext (sLit "Adding error:") <+> (mkLocMessage loc (msg $$ extra))) ;
481 errs_var <- getErrsVar ;
482 rdr_env <- getGlobalRdrEnv ;
484 let { err = mkLongErrMsg loc (mkPrintUnqualified dflags rdr_env) msg extra } ;
485 (warns, errs) <- readMutVar errs_var ;
486 writeMutVar errs_var (warns, errs `snocBag` err) }
488 addErrs :: [(SrcSpan,Message)] -> TcRn ()
489 addErrs msgs = mapM_ add msgs
491 add (loc,msg) = addErrAt loc msg
493 addReport :: Message -> TcRn ()
494 addReport msg = do loc <- getSrcSpanM; addReportAt loc msg
496 addReportAt :: SrcSpan -> Message -> TcRn ()
498 = do { errs_var <- getErrsVar ;
499 rdr_env <- getGlobalRdrEnv ;
501 let { warn = mkWarnMsg loc (mkPrintUnqualified dflags rdr_env) msg } ;
502 (warns, errs) <- readMutVar errs_var ;
503 writeMutVar errs_var (warns `snocBag` warn, errs) }
505 addWarn :: Message -> TcRn ()
506 addWarn msg = addReport (ptext (sLit "Warning:") <+> msg)
508 addWarnAt :: SrcSpan -> Message -> TcRn ()
509 addWarnAt loc msg = addReportAt loc (ptext (sLit "Warning:") <+> msg)
511 addLocWarn :: Located e -> (e -> Message) -> TcRn ()
512 addLocWarn (L loc e) fn = addReportAt loc (fn e)
514 checkErr :: Bool -> Message -> TcRn ()
515 -- Add the error if the bool is False
516 checkErr ok msg = unless ok (addErr msg)
518 warnIf :: Bool -> Message -> TcRn ()
519 warnIf True msg = addWarn msg
520 warnIf False _ = return ()
522 addMessages :: Messages -> TcRn ()
523 addMessages (m_warns, m_errs)
524 = do { errs_var <- getErrsVar ;
525 (warns, errs) <- readMutVar errs_var ;
526 writeMutVar errs_var (warns `unionBags` m_warns,
527 errs `unionBags` m_errs) }
529 discardWarnings :: TcRn a -> TcRn a
530 -- Ignore warnings inside the thing inside;
531 -- used to ignore-unused-variable warnings inside derived code
532 -- With -dppr-debug, the effects is switched off, so you can still see
533 -- what warnings derived code would give
534 discardWarnings thing_inside
535 | opt_PprStyle_Debug = thing_inside
537 = do { errs_var <- newMutVar emptyMessages
538 ; result <- setErrsVar errs_var thing_inside
539 ; (_warns, errs) <- readMutVar errs_var
540 ; addMessages (emptyBag, errs)
546 try_m :: TcRn r -> TcRn (Either IOException r)
547 -- Does try_m, with a debug-trace on failure
549 = do { mb_r <- tryM thing ;
551 Left exn -> do { traceTc (exn_msg exn); return mb_r }
552 Right _ -> return mb_r }
554 exn_msg exn = text "tryTc/recoverM recovering from" <+> text (showException exn)
556 -----------------------
557 recoverM :: TcRn r -- Recovery action; do this if the main one fails
558 -> TcRn r -- Main action: do this first
560 -- Errors in 'thing' are retained
561 recoverM recover thing
562 = do { mb_res <- try_m thing ;
565 Right res -> return res }
568 -----------------------
569 mapAndRecoverM :: (a -> TcRn b) -> [a] -> TcRn [b]
570 -- Drop elements of the input that fail, so the result
571 -- list can be shorter than the argument list
572 mapAndRecoverM _ [] = return []
573 mapAndRecoverM f (x:xs) = do { mb_r <- try_m (f x)
574 ; rs <- mapAndRecoverM f xs
575 ; return (case mb_r of
580 -----------------------
581 tryTc :: TcRn a -> TcRn (Messages, Maybe a)
582 -- (tryTc m) executes m, and returns
583 -- Just r, if m succeeds (returning r)
584 -- Nothing, if m fails
585 -- It also returns all the errors and warnings accumulated by m
586 -- It always succeeds (never raises an exception)
588 = do { errs_var <- newMutVar emptyMessages ;
589 res <- try_m (setErrsVar errs_var m) ;
590 msgs <- readMutVar errs_var ;
591 return (msgs, case res of
593 Right val -> Just val)
594 -- The exception is always the IOEnv built-in
595 -- in exception; see IOEnv.failM
598 -----------------------
599 tryTcErrs :: TcRn a -> TcRn (Messages, Maybe a)
600 -- Run the thing, returning
601 -- Just r, if m succceeds with no error messages
602 -- Nothing, if m fails, or if it succeeds but has error messages
603 -- Either way, the messages are returned; even in the Just case
604 -- there might be warnings
606 = do { (msgs, res) <- tryTc thing
608 ; let errs_found = errorsFound dflags msgs
609 ; return (msgs, case res of
611 Just val | errs_found -> Nothing
612 | otherwise -> Just val)
615 -----------------------
616 tryTcLIE :: TcM a -> TcM (Messages, Maybe a)
617 -- Just like tryTcErrs, except that it ensures that the LIE
618 -- for the thing is propagated only if there are no errors
619 -- Hence it's restricted to the type-check monad
620 tryTcLIE thing_inside
621 = do { ((msgs, mb_res), lie) <- getLIE (tryTcErrs thing_inside) ;
623 Nothing -> return (msgs, Nothing)
624 Just val -> do { extendLIEs lie; return (msgs, Just val) }
627 -----------------------
628 tryTcLIE_ :: TcM r -> TcM r -> TcM r
629 -- (tryTcLIE_ r m) tries m;
630 -- if m succeeds with no error messages, it's the answer
631 -- otherwise tryTcLIE_ drops everything from m and tries r instead.
632 tryTcLIE_ recover main
633 = do { (msgs, mb_res) <- tryTcLIE main
635 Just val -> do { addMessages msgs -- There might be warnings
637 Nothing -> recover -- Discard all msgs
640 -----------------------
641 checkNoErrs :: TcM r -> TcM r
642 -- (checkNoErrs m) succeeds iff m succeeds and generates no errors
643 -- If m fails then (checkNoErrsTc m) fails.
644 -- If m succeeds, it checks whether m generated any errors messages
645 -- (it might have recovered internally)
646 -- If so, it fails too.
647 -- Regardless, any errors generated by m are propagated to the enclosing context.
649 = do { (msgs, mb_res) <- tryTcLIE main
653 Just val -> return val
656 ifErrsM :: TcRn r -> TcRn r -> TcRn r
657 -- ifErrsM bale_out main
658 -- does 'bale_out' if there are errors in errors collection
659 -- otherwise does 'main'
660 ifErrsM bale_out normal
661 = do { errs_var <- getErrsVar ;
662 msgs <- readMutVar errs_var ;
664 if errorsFound dflags msgs then
669 failIfErrsM :: TcRn ()
670 -- Useful to avoid error cascades
671 failIfErrsM = ifErrsM failM (return ())
675 %************************************************************************
677 Context management and error message generation
680 %************************************************************************
683 getErrCtxt :: TcM ErrCtxt
684 getErrCtxt = do { env <- getLclEnv; return (tcl_ctxt env) }
686 setErrCtxt :: ErrCtxt -> TcM a -> TcM a
687 setErrCtxt ctxt = updLclEnv (\ env -> env { tcl_ctxt = ctxt })
689 addErrCtxt :: Message -> TcM a -> TcM a
690 addErrCtxt msg = addErrCtxtM (\env -> return (env, msg))
692 addErrCtxtM :: (TidyEnv -> TcM (TidyEnv, Message)) -> TcM a -> TcM a
693 addErrCtxtM msg = updCtxt (\ msgs -> msg : msgs)
695 -- Helper function for the above
696 updCtxt :: (ErrCtxt -> ErrCtxt) -> TcM a -> TcM a
697 updCtxt upd = updLclEnv (\ env@(TcLclEnv { tcl_ctxt = ctxt }) ->
698 env { tcl_ctxt = upd ctxt })
700 -- Conditionally add an error context
701 maybeAddErrCtxt :: Maybe Message -> TcM a -> TcM a
702 maybeAddErrCtxt (Just msg) thing_inside = addErrCtxt msg thing_inside
703 maybeAddErrCtxt Nothing thing_inside = thing_inside
705 popErrCtxt :: TcM a -> TcM a
706 popErrCtxt = updCtxt (\ msgs -> case msgs of { [] -> []; (_ : ms) -> ms })
708 getInstLoc :: InstOrigin -> TcM InstLoc
710 = do { loc <- getSrcSpanM ; env <- getLclEnv ;
711 return (InstLoc origin loc (tcl_ctxt env)) }
713 addInstCtxt :: InstLoc -> TcM a -> TcM a
714 -- Add the SrcSpan and context from the first Inst in the list
715 -- (they all have similar locations)
716 addInstCtxt (InstLoc _ src_loc ctxt) thing_inside
717 = setSrcSpan src_loc (updCtxt (\_ -> ctxt) thing_inside)
720 The addErrTc functions add an error message, but do not cause failure.
721 The 'M' variants pass a TidyEnv that has already been used to
722 tidy up the message; we then use it to tidy the context messages
725 addErrTc :: Message -> TcM ()
726 addErrTc err_msg = do { env0 <- tcInitTidyEnv
727 ; addErrTcM (env0, err_msg) }
729 addErrsTc :: [Message] -> TcM ()
730 addErrsTc err_msgs = mapM_ addErrTc err_msgs
732 addErrTcM :: (TidyEnv, Message) -> TcM ()
733 addErrTcM (tidy_env, err_msg)
734 = do { ctxt <- getErrCtxt ;
736 add_err_tcm tidy_env err_msg loc ctxt }
739 The failWith functions add an error message and cause failure
742 failWithTc :: Message -> TcM a -- Add an error message and fail
744 = addErrTc err_msg >> failM
746 failWithTcM :: (TidyEnv, Message) -> TcM a -- Add an error message and fail
747 failWithTcM local_and_msg
748 = addErrTcM local_and_msg >> failM
750 checkTc :: Bool -> Message -> TcM () -- Check that the boolean is true
751 checkTc True _ = return ()
752 checkTc False err = failWithTc err
755 Warnings have no 'M' variant, nor failure
758 addWarnTc :: Message -> TcM ()
759 addWarnTc msg = do { env0 <- tcInitTidyEnv
760 ; addWarnTcM (env0, msg) }
762 addWarnTcM :: (TidyEnv, Message) -> TcM ()
763 addWarnTcM (env0, msg)
764 = do { ctxt <- getErrCtxt ;
765 ctxt_msgs <- do_ctxt env0 ctxt ;
766 addReport (vcat (ptext (sLit "Warning:") <+> msg : ctxt_to_use ctxt_msgs)) }
768 warnTc :: Bool -> Message -> TcM ()
769 warnTc warn_if_true warn_msg
770 | warn_if_true = addWarnTc warn_msg
771 | otherwise = return ()
774 -----------------------------------
777 We initialise the "tidy-env", used for tidying types before printing,
778 by building a reverse map from the in-scope type variables to the
779 OccName that the programmer originally used for them
782 tcInitTidyEnv :: TcM TidyEnv
784 = do { lcl_env <- getLclEnv
785 ; let nm_tv_prs = [ (name, tcGetTyVar "tcInitTidyEnv" ty)
786 | ATyVar name ty <- nameEnvElts (tcl_env lcl_env)
788 ; return (foldl add emptyTidyEnv nm_tv_prs) }
790 add (env,subst) (name, tyvar)
791 = case tidyOccName env (nameOccName name) of
792 (env', occ') -> (env', extendVarEnv subst tyvar tyvar')
794 tyvar' = setTyVarName tyvar name'
795 name' = tidyNameOcc name occ'
798 -----------------------------------
799 Other helper functions
802 add_err_tcm :: TidyEnv -> Message -> SrcSpan
803 -> [TidyEnv -> TcM (TidyEnv, SDoc)]
805 add_err_tcm tidy_env err_msg loc ctxt
806 = do { ctxt_msgs <- do_ctxt tidy_env ctxt ;
807 addLongErrAt loc err_msg (vcat (ctxt_to_use ctxt_msgs)) }
809 do_ctxt :: TidyEnv -> [TidyEnv -> TcM (TidyEnv, SDoc)] -> TcM [SDoc]
812 do_ctxt tidy_env (c:cs)
813 = do { (tidy_env', m) <- c tidy_env ;
814 ms <- do_ctxt tidy_env' cs ;
817 ctxt_to_use :: [SDoc] -> [SDoc]
818 ctxt_to_use ctxt | opt_PprStyle_Debug = ctxt
819 | otherwise = take 3 ctxt
822 debugTc is useful for monadic debugging code
825 debugTc :: TcM () -> TcM ()
828 | otherwise = return ()
831 %************************************************************************
833 Type constraints (the so-called LIE)
835 %************************************************************************
838 nextDFunIndex :: TcM Int -- Get the next dfun index
839 nextDFunIndex = do { env <- getGblEnv
840 ; let dfun_n_var = tcg_dfun_n env
841 ; n <- readMutVar dfun_n_var
842 ; writeMutVar dfun_n_var (n+1)
845 getLIEVar :: TcM (TcRef LIE)
846 getLIEVar = do { env <- getLclEnv; return (tcl_lie env) }
848 setLIEVar :: TcRef LIE -> TcM a -> TcM a
849 setLIEVar lie_var = updLclEnv (\ env -> env { tcl_lie = lie_var })
851 getLIE :: TcM a -> TcM (a, [Inst])
852 -- (getLIE m) runs m, and returns the type constraints it generates
854 = do { lie_var <- newMutVar emptyLIE ;
855 res <- updLclEnv (\ env -> env { tcl_lie = lie_var })
857 lie <- readMutVar lie_var ;
858 return (res, lieToList lie) }
860 extendLIE :: Inst -> TcM ()
862 = do { lie_var <- getLIEVar ;
863 lie <- readMutVar lie_var ;
864 writeMutVar lie_var (inst `consLIE` lie) }
866 extendLIEs :: [Inst] -> TcM ()
870 = do { lie_var <- getLIEVar ;
871 lie <- readMutVar lie_var ;
872 writeMutVar lie_var (mkLIE insts `plusLIE` lie) }
876 setLclTypeEnv :: TcLclEnv -> TcM a -> TcM a
877 -- Set the local type envt, but do *not* disturb other fields,
878 -- notably the lie_var
879 setLclTypeEnv lcl_env thing_inside
880 = updLclEnv upd thing_inside
882 upd env = env { tcl_env = tcl_env lcl_env,
883 tcl_tyvars = tcl_tyvars lcl_env }
887 %************************************************************************
889 Template Haskell context
891 %************************************************************************
894 recordThUse :: TcM ()
895 recordThUse = do { env <- getGblEnv; writeMutVar (tcg_th_used env) True }
897 keepAliveTc :: Id -> TcM () -- Record the name in the keep-alive set
899 | isLocalId id = do { env <- getGblEnv;
900 ; updMutVar (tcg_keep env) (`addOneToNameSet` idName id) }
901 | otherwise = return ()
903 keepAliveSetTc :: NameSet -> TcM () -- Record the name in the keep-alive set
904 keepAliveSetTc ns = do { env <- getGblEnv;
905 ; updMutVar (tcg_keep env) (`unionNameSets` ns) }
907 getStage :: TcM ThStage
908 getStage = do { env <- getLclEnv; return (tcl_th_ctxt env) }
910 setStage :: ThStage -> TcM a -> TcM a
911 setStage s = updLclEnv (\ env -> env { tcl_th_ctxt = s })
915 %************************************************************************
917 Stuff for the renamer's local env
919 %************************************************************************
922 getLocalRdrEnv :: RnM LocalRdrEnv
923 getLocalRdrEnv = do { env <- getLclEnv; return (tcl_rdr env) }
925 setLocalRdrEnv :: LocalRdrEnv -> RnM a -> RnM a
926 setLocalRdrEnv rdr_env thing_inside
927 = updLclEnv (\env -> env {tcl_rdr = rdr_env}) thing_inside
931 %************************************************************************
933 Stuff for interface decls
935 %************************************************************************
938 mkIfLclEnv :: Module -> SDoc -> IfLclEnv
939 mkIfLclEnv mod loc = IfLclEnv { if_mod = mod,
941 if_tv_env = emptyUFM,
942 if_id_env = emptyUFM }
944 initIfaceTcRn :: IfG a -> TcRn a
945 initIfaceTcRn thing_inside
946 = do { tcg_env <- getGblEnv
947 ; let { if_env = IfGblEnv { if_rec_types = Just (tcg_mod tcg_env, get_type_env) }
948 ; get_type_env = readMutVar (tcg_type_env_var tcg_env) }
949 ; setEnvs (if_env, ()) thing_inside }
951 initIfaceExtCore :: IfL a -> TcRn a
952 initIfaceExtCore thing_inside
953 = do { tcg_env <- getGblEnv
954 ; let { mod = tcg_mod tcg_env
955 ; doc = ptext (sLit "External Core file for") <+> quotes (ppr mod)
956 ; if_env = IfGblEnv {
957 if_rec_types = Just (mod, return (tcg_type_env tcg_env)) }
958 ; if_lenv = mkIfLclEnv mod doc
960 ; setEnvs (if_env, if_lenv) thing_inside }
962 initIfaceCheck :: HscEnv -> IfG a -> IO a
963 -- Used when checking the up-to-date-ness of the old Iface
964 -- Initialise the environment with no useful info at all
965 initIfaceCheck hsc_env do_this
966 = do let rec_types = case hsc_type_env_var hsc_env of
967 Just (mod,var) -> Just (mod, readMutVar var)
969 gbl_env = IfGblEnv { if_rec_types = rec_types }
970 initTcRnIf 'i' hsc_env gbl_env () do_this
972 initIfaceTc :: ModIface
973 -> (TcRef TypeEnv -> IfL a) -> TcRnIf gbl lcl a
974 -- Used when type-checking checking an up-to-date interface file
975 -- No type envt from the current module, but we do know the module dependencies
976 initIfaceTc iface do_this
977 = do { tc_env_var <- newMutVar emptyTypeEnv
978 ; let { gbl_env = IfGblEnv { if_rec_types = Just (mod, readMutVar tc_env_var) } ;
979 ; if_lenv = mkIfLclEnv mod doc
981 ; setEnvs (gbl_env, if_lenv) (do_this tc_env_var)
984 mod = mi_module iface
985 doc = ptext (sLit "The interface for") <+> quotes (ppr mod)
987 initIfaceRules :: HscEnv -> ModGuts -> IfG a -> IO a
988 -- Used when sucking in new Rules in SimplCore
989 -- We have available the type envt of the module being compiled, and we must use it
990 initIfaceRules hsc_env guts do_this
992 type_info = (mg_module guts, return (mg_types guts))
993 ; gbl_env = IfGblEnv { if_rec_types = Just type_info } ;
996 -- Run the thing; any exceptions just bubble out from here
997 ; initTcRnIf 'i' hsc_env gbl_env () do_this
1000 initIfaceLcl :: Module -> SDoc -> IfL a -> IfM lcl a
1001 initIfaceLcl mod loc_doc thing_inside
1002 = setLclEnv (mkIfLclEnv mod loc_doc) thing_inside
1004 getIfModule :: IfL Module
1005 getIfModule = do { env <- getLclEnv; return (if_mod env) }
1007 --------------------
1008 failIfM :: Message -> IfL a
1009 -- The Iface monad doesn't have a place to accumulate errors, so we
1010 -- just fall over fast if one happens; it "shouldnt happen".
1011 -- We use IfL here so that we can get context info out of the local env
1013 = do { env <- getLclEnv
1014 ; let full_msg = (if_loc env <> colon) $$ nest 2 msg
1015 ; liftIO (printErrs (full_msg defaultErrStyle))
1018 --------------------
1019 forkM_maybe :: SDoc -> IfL a -> IfL (Maybe a)
1020 -- Run thing_inside in an interleaved thread.
1021 -- It shares everything with the parent thread, so this is DANGEROUS.
1023 -- It returns Nothing if the computation fails
1025 -- It's used for lazily type-checking interface
1026 -- signatures, which is pretty benign
1028 forkM_maybe doc thing_inside
1029 = do { unsafeInterleaveM $
1030 do { traceIf (text "Starting fork {" <+> doc)
1032 updLclEnv (\env -> env { if_loc = if_loc env $$ doc }) $
1035 Right r -> do { traceIf (text "} ending fork" <+> doc)
1039 -- Bleat about errors in the forked thread, if -ddump-if-trace is on
1040 -- Otherwise we silently discard errors. Errors can legitimately
1041 -- happen when compiling interface signatures (see tcInterfaceSigs)
1042 ifOptM Opt_D_dump_if_trace
1043 (print_errs (hang (text "forkM failed:" <+> doc)
1044 4 (text (show exn))))
1046 ; traceIf (text "} ending fork (badly)" <+> doc)
1050 print_errs sdoc = liftIO (printErrs (sdoc defaultErrStyle))
1052 forkM :: SDoc -> IfL a -> IfL a
1053 forkM doc thing_inside
1054 = do { mb_res <- forkM_maybe doc thing_inside
1055 ; return (case mb_res of
1056 Nothing -> pgmError "Cannot continue after interface file error"
1057 -- pprPanic "forkM" doc