2 % (c) The University of Glasgow 2006
12 import TcRnTypes -- Re-export all
13 import IOEnv -- Re-export all
15 import HsSyn hiding (LIE)
46 import Control.Exception
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_deprecs = NoDeprecs,
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
152 initTcPrintErrors env mod todo = do
153 (msgs, res) <- initTc env HsSrcFile False mod todo
154 printErrorsAndWarnings (hsc_dflags env) msgs
158 %************************************************************************
162 %************************************************************************
166 initTcRnIf :: Char -- Tag for unique supply
171 initTcRnIf uniq_tag hsc_env gbl_env lcl_env thing_inside
172 = do { us <- mkSplitUniqSupply uniq_tag ;
173 ; us_var <- newIORef us ;
175 ; let { env = Env { env_top = hsc_env,
180 ; runIOEnv env thing_inside
184 %************************************************************************
188 %************************************************************************
191 getTopEnv :: TcRnIf gbl lcl HscEnv
192 getTopEnv = do { env <- getEnv; return (env_top env) }
194 getGblEnv :: TcRnIf gbl lcl gbl
195 getGblEnv = do { env <- getEnv; return (env_gbl env) }
197 updGblEnv :: (gbl -> gbl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
198 updGblEnv upd = updEnv (\ env@(Env { env_gbl = gbl }) ->
199 env { env_gbl = upd gbl })
201 setGblEnv :: gbl -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
202 setGblEnv gbl_env = updEnv (\ env -> env { env_gbl = gbl_env })
204 getLclEnv :: TcRnIf gbl lcl lcl
205 getLclEnv = do { env <- getEnv; return (env_lcl env) }
207 updLclEnv :: (lcl -> lcl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
208 updLclEnv upd = updEnv (\ env@(Env { env_lcl = lcl }) ->
209 env { env_lcl = upd lcl })
211 setLclEnv :: lcl' -> TcRnIf gbl lcl' a -> TcRnIf gbl lcl a
212 setLclEnv lcl_env = updEnv (\ env -> env { env_lcl = lcl_env })
214 getEnvs :: TcRnIf gbl lcl (gbl, lcl)
215 getEnvs = do { env <- getEnv; return (env_gbl env, env_lcl env) }
217 setEnvs :: (gbl', lcl') -> TcRnIf gbl' lcl' a -> TcRnIf gbl lcl a
218 setEnvs (gbl_env, lcl_env) = updEnv (\ env -> env { env_gbl = gbl_env, env_lcl = lcl_env })
225 getDOpts :: TcRnIf gbl lcl DynFlags
226 getDOpts = do { env <- getTopEnv; return (hsc_dflags env) }
228 doptM :: DynFlag -> TcRnIf gbl lcl Bool
229 doptM flag = do { dflags <- getDOpts; return (dopt flag dflags) }
231 setOptM :: DynFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
232 setOptM flag = updEnv (\ env@(Env { env_top = top }) ->
233 env { env_top = top { hsc_dflags = dopt_set (hsc_dflags top) flag}} )
235 unsetOptM :: DynFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
236 unsetOptM flag = updEnv (\ env@(Env { env_top = top }) ->
237 env { env_top = top { hsc_dflags = dopt_unset (hsc_dflags top) flag}} )
239 -- | Do it flag is true
240 ifOptM :: DynFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl ()
241 ifOptM flag thing_inside = do { b <- doptM flag;
242 if b then thing_inside else return () }
244 getGhcMode :: TcRnIf gbl lcl GhcMode
245 getGhcMode = do { env <- getTopEnv; return (ghcMode (hsc_dflags env)) }
249 getEpsVar :: TcRnIf gbl lcl (TcRef ExternalPackageState)
250 getEpsVar = do { env <- getTopEnv; return (hsc_EPS env) }
252 getEps :: TcRnIf gbl lcl ExternalPackageState
253 getEps = do { env <- getTopEnv; readMutVar (hsc_EPS env) }
255 -- Updating the EPS. This should be an atomic operation.
256 -- Note the delicate 'seq' which forces the EPS before putting it in the
257 -- variable. Otherwise what happens is that we get
258 -- write eps_var (....(unsafeRead eps_var)....)
259 -- and if the .... is strict, that's obviously bottom. By forcing it beforehand
260 -- we make the unsafeRead happen before we update the variable.
262 updateEps :: (ExternalPackageState -> (ExternalPackageState, a))
264 updateEps upd_fn = do { traceIf (text "updating EPS")
265 ; eps_var <- getEpsVar
266 ; eps <- readMutVar eps_var
267 ; let { (eps', val) = upd_fn eps }
268 ; seq eps' (writeMutVar eps_var eps')
271 updateEps_ :: (ExternalPackageState -> ExternalPackageState)
273 updateEps_ upd_fn = do { traceIf (text "updating EPS_")
274 ; eps_var <- getEpsVar
275 ; eps <- readMutVar eps_var
276 ; let { eps' = upd_fn eps }
277 ; seq eps' (writeMutVar eps_var eps') }
279 getHpt :: TcRnIf gbl lcl HomePackageTable
280 getHpt = do { env <- getTopEnv; return (hsc_HPT env) }
282 getEpsAndHpt :: TcRnIf gbl lcl (ExternalPackageState, HomePackageTable)
283 getEpsAndHpt = do { env <- getTopEnv; eps <- readMutVar (hsc_EPS env)
284 ; return (eps, hsc_HPT env) }
287 %************************************************************************
291 %************************************************************************
294 newUnique :: TcRnIf gbl lcl Unique
296 = do { env <- getEnv ;
297 let { u_var = env_us env } ;
298 us <- readMutVar u_var ;
299 case splitUniqSupply us of { (us1,_) -> do {
300 writeMutVar u_var us1 ;
301 return $! uniqFromSupply us }}}
302 -- NOTE 1: we strictly split the supply, to avoid the possibility of leaving
303 -- a chain of unevaluated supplies behind.
304 -- NOTE 2: we use the uniq in the supply from the MutVar directly, and
305 -- throw away one half of the new split supply. This is safe because this
306 -- is the only place we use that unique. Using the other half of the split
307 -- supply is safer, but slower.
309 newUniqueSupply :: TcRnIf gbl lcl UniqSupply
311 = do { env <- getEnv ;
312 let { u_var = env_us env } ;
313 us <- readMutVar u_var ;
314 case splitUniqSupply us of { (us1,us2) -> do {
315 writeMutVar u_var us1 ;
318 newLocalName :: Name -> TcRnIf gbl lcl Name
319 newLocalName name -- Make a clone
320 = do { uniq <- newUnique
321 ; return (mkInternalName uniq (nameOccName name) (getSrcSpan name)) }
323 newSysLocalIds :: FastString -> [TcType] -> TcRnIf gbl lcl [TcId]
324 newSysLocalIds fs tys
325 = do { us <- newUniqueSupply
326 ; return (zipWith (mkSysLocal fs) (uniqsFromSupply us) tys) }
330 %************************************************************************
334 %************************************************************************
337 traceTc, traceRn, traceSplice :: SDoc -> TcRn ()
338 traceRn = traceOptTcRn Opt_D_dump_rn_trace
339 traceTc = traceOptTcRn Opt_D_dump_tc_trace
340 traceSplice = traceOptTcRn Opt_D_dump_splices
343 traceIf, traceHiDiffs :: SDoc -> TcRnIf m n ()
344 traceIf = traceOptIf Opt_D_dump_if_trace
345 traceHiDiffs = traceOptIf Opt_D_dump_hi_diffs
348 traceOptIf :: DynFlag -> SDoc -> TcRnIf m n () -- No RdrEnv available, so qualify everything
349 traceOptIf flag doc = ifOptM flag $
350 liftIO (printForUser stderr alwaysQualify doc)
352 traceOptTcRn :: DynFlag -> SDoc -> TcRn ()
353 traceOptTcRn flag doc = ifOptM flag $ do
356 ; env0 <- tcInitTidyEnv
357 ; ctxt_msgs <- do_ctxt env0 ctxt
358 ; let real_doc = mkLocMessage loc (vcat (doc : ctxt_to_use ctxt_msgs))
359 ; dumpTcRn real_doc }
361 dumpTcRn :: SDoc -> TcRn ()
362 dumpTcRn doc = do { rdr_env <- getGlobalRdrEnv ;
364 liftIO (printForUser stderr (mkPrintUnqualified dflags rdr_env) doc) }
366 dumpOptTcRn :: DynFlag -> SDoc -> TcRn ()
367 dumpOptTcRn flag doc = ifOptM flag (dumpTcRn doc)
371 %************************************************************************
373 Typechecker global environment
375 %************************************************************************
378 getModule :: TcRn Module
379 getModule = do { env <- getGblEnv; return (tcg_mod env) }
381 setModule :: Module -> TcRn a -> TcRn a
382 setModule mod thing_inside = updGblEnv (\env -> env { tcg_mod = mod }) thing_inside
384 tcIsHsBoot :: TcRn Bool
385 tcIsHsBoot = do { env <- getGblEnv; return (isHsBoot (tcg_src env)) }
387 getGlobalRdrEnv :: TcRn GlobalRdrEnv
388 getGlobalRdrEnv = do { env <- getGblEnv; return (tcg_rdr_env env) }
390 getRdrEnvs :: TcRn (GlobalRdrEnv, LocalRdrEnv)
391 getRdrEnvs = do { (gbl,lcl) <- getEnvs; return (tcg_rdr_env gbl, tcl_rdr lcl) }
393 getImports :: TcRn ImportAvails
394 getImports = do { env <- getGblEnv; return (tcg_imports env) }
396 getFixityEnv :: TcRn FixityEnv
397 getFixityEnv = do { env <- getGblEnv; return (tcg_fix_env env) }
399 extendFixityEnv :: [(Name,FixItem)] -> RnM a -> RnM a
400 extendFixityEnv new_bit
401 = updGblEnv (\env@(TcGblEnv { tcg_fix_env = old_fix_env }) ->
402 env {tcg_fix_env = extendNameEnvList old_fix_env new_bit})
404 getRecFieldEnv :: TcRn RecFieldEnv
405 getRecFieldEnv = do { env <- getGblEnv; return (tcg_field_env env) }
407 extendRecFieldEnv :: RecFieldEnv -> RnM a -> RnM a
408 extendRecFieldEnv new_bit
409 = updGblEnv (\env@(TcGblEnv { tcg_field_env = old_env }) ->
410 env {tcg_field_env = old_env `plusNameEnv` new_bit})
412 getDeclaredDefaultTys :: TcRn (Maybe [Type])
413 getDeclaredDefaultTys = do { env <- getGblEnv; return (tcg_default env) }
416 %************************************************************************
420 %************************************************************************
423 getSrcSpanM :: TcRn SrcSpan
424 -- Avoid clash with Name.getSrcLoc
425 getSrcSpanM = do { env <- getLclEnv; return (tcl_loc env) }
427 setSrcSpan :: SrcSpan -> TcRn a -> TcRn a
428 setSrcSpan loc thing_inside
429 | isGoodSrcSpan loc = updLclEnv (\env -> env { tcl_loc = loc }) thing_inside
430 | otherwise = thing_inside -- Don't overwrite useful info with useless
432 addLocM :: (a -> TcM b) -> Located a -> TcM b
433 addLocM fn (L loc a) = setSrcSpan loc $ fn a
435 wrapLocM :: (a -> TcM b) -> Located a -> TcM (Located b)
436 wrapLocM fn (L loc a) = setSrcSpan loc $ do b <- fn a; return (L loc b)
438 wrapLocFstM :: (a -> TcM (b,c)) -> Located a -> TcM (Located b, c)
439 wrapLocFstM fn (L loc a) =
444 wrapLocSndM :: (a -> TcM (b,c)) -> Located a -> TcM (b, Located c)
445 wrapLocSndM fn (L loc a) =
453 getErrsVar :: TcRn (TcRef Messages)
454 getErrsVar = do { env <- getLclEnv; return (tcl_errs env) }
456 setErrsVar :: TcRef Messages -> TcRn a -> TcRn a
457 setErrsVar v = updLclEnv (\ env -> env { tcl_errs = v })
459 addErr :: Message -> TcRn ()
460 addErr msg = do { loc <- getSrcSpanM ; addErrAt loc msg }
462 addLocErr :: Located e -> (e -> Message) -> TcRn ()
463 addLocErr (L loc e) fn = addErrAt loc (fn e)
465 addErrAt :: SrcSpan -> Message -> TcRn ()
466 addErrAt loc msg = addLongErrAt loc msg empty
468 addLongErrAt :: SrcSpan -> Message -> Message -> TcRn ()
469 addLongErrAt loc msg extra
470 = do { traceTc (ptext (sLit "Adding error:") <+> (mkLocMessage loc (msg $$ extra))) ;
471 errs_var <- getErrsVar ;
472 rdr_env <- getGlobalRdrEnv ;
474 let { err = mkLongErrMsg loc (mkPrintUnqualified dflags rdr_env) msg extra } ;
475 (warns, errs) <- readMutVar errs_var ;
476 writeMutVar errs_var (warns, errs `snocBag` err) }
478 addErrs :: [(SrcSpan,Message)] -> TcRn ()
479 addErrs msgs = mapM_ add msgs
481 add (loc,msg) = addErrAt loc msg
483 addReport :: Message -> TcRn ()
484 addReport msg = do loc <- getSrcSpanM; addReportAt loc msg
486 addReportAt :: SrcSpan -> Message -> TcRn ()
488 = do { errs_var <- getErrsVar ;
489 rdr_env <- getGlobalRdrEnv ;
491 let { warn = mkWarnMsg loc (mkPrintUnqualified dflags rdr_env) msg } ;
492 (warns, errs) <- readMutVar errs_var ;
493 writeMutVar errs_var (warns `snocBag` warn, errs) }
495 addWarn :: Message -> TcRn ()
496 addWarn msg = addReport (ptext (sLit "Warning:") <+> msg)
498 addWarnAt :: SrcSpan -> Message -> TcRn ()
499 addWarnAt loc msg = addReportAt loc (ptext (sLit "Warning:") <+> msg)
501 addLocWarn :: Located e -> (e -> Message) -> TcRn ()
502 addLocWarn (L loc e) fn = addReportAt loc (fn e)
504 checkErr :: Bool -> Message -> TcRn ()
505 -- Add the error if the bool is False
506 checkErr ok msg = unless ok (addErr msg)
508 warnIf :: Bool -> Message -> TcRn ()
509 warnIf True msg = addWarn msg
510 warnIf False _ = return ()
512 addMessages :: Messages -> TcRn ()
513 addMessages (m_warns, m_errs)
514 = do { errs_var <- getErrsVar ;
515 (warns, errs) <- readMutVar errs_var ;
516 writeMutVar errs_var (warns `unionBags` m_warns,
517 errs `unionBags` m_errs) }
519 discardWarnings :: TcRn a -> TcRn a
520 -- Ignore warnings inside the thing inside;
521 -- used to ignore-unused-variable warnings inside derived code
522 -- With -dppr-debug, the effects is switched off, so you can still see
523 -- what warnings derived code would give
524 discardWarnings thing_inside
525 | opt_PprStyle_Debug = thing_inside
527 = do { errs_var <- newMutVar emptyMessages
528 ; result <- setErrsVar errs_var thing_inside
529 ; (_warns, errs) <- readMutVar errs_var
530 ; addMessages (emptyBag, errs)
536 try_m :: TcRn r -> TcRn (Either Exception r)
537 -- Does try_m, with a debug-trace on failure
539 = do { mb_r <- tryM thing ;
541 Left exn -> do { traceTc (exn_msg exn); return mb_r }
542 Right _ -> return mb_r }
544 exn_msg exn = text "tryTc/recoverM recovering from" <+> text (showException exn)
546 -----------------------
547 recoverM :: TcRn r -- Recovery action; do this if the main one fails
548 -> TcRn r -- Main action: do this first
550 -- Errors in 'thing' are retained
551 recoverM recover thing
552 = do { mb_res <- try_m thing ;
555 Right res -> return res }
558 -----------------------
559 mapAndRecoverM :: (a -> TcRn b) -> [a] -> TcRn [b]
560 -- Drop elements of the input that fail, so the result
561 -- list can be shorter than the argument list
562 mapAndRecoverM _ [] = return []
563 mapAndRecoverM f (x:xs) = do { mb_r <- tryM (f x)
564 ; rs <- mapAndRecoverM f xs
565 ; return (case mb_r of
570 -----------------------
571 tryTc :: TcRn a -> TcRn (Messages, Maybe a)
572 -- (tryTc m) executes m, and returns
573 -- Just r, if m succeeds (returning r)
574 -- Nothing, if m fails
575 -- It also returns all the errors and warnings accumulated by m
576 -- It always succeeds (never raises an exception)
578 = do { errs_var <- newMutVar emptyMessages ;
579 res <- try_m (setErrsVar errs_var m) ;
580 msgs <- readMutVar errs_var ;
581 return (msgs, case res of
583 Right val -> Just val)
584 -- The exception is always the IOEnv built-in
585 -- in exception; see IOEnv.failM
588 -----------------------
589 tryTcErrs :: TcRn a -> TcRn (Messages, Maybe a)
590 -- Run the thing, returning
591 -- Just r, if m succceeds with no error messages
592 -- Nothing, if m fails, or if it succeeds but has error messages
593 -- Either way, the messages are returned; even in the Just case
594 -- there might be warnings
596 = do { (msgs, res) <- tryTc thing
598 ; let errs_found = errorsFound dflags msgs
599 ; return (msgs, case res of
601 Just val | errs_found -> Nothing
602 | otherwise -> Just val)
605 -----------------------
606 tryTcLIE :: TcM a -> TcM (Messages, Maybe a)
607 -- Just like tryTcErrs, except that it ensures that the LIE
608 -- for the thing is propagated only if there are no errors
609 -- Hence it's restricted to the type-check monad
610 tryTcLIE thing_inside
611 = do { ((msgs, mb_res), lie) <- getLIE (tryTcErrs thing_inside) ;
613 Nothing -> return (msgs, Nothing)
614 Just val -> do { extendLIEs lie; return (msgs, Just val) }
617 -----------------------
618 tryTcLIE_ :: TcM r -> TcM r -> TcM r
619 -- (tryTcLIE_ r m) tries m;
620 -- if m succeeds with no error messages, it's the answer
621 -- otherwise tryTcLIE_ drops everything from m and tries r instead.
622 tryTcLIE_ recover main
623 = do { (msgs, mb_res) <- tryTcLIE main
625 Just val -> do { addMessages msgs -- There might be warnings
627 Nothing -> recover -- Discard all msgs
630 -----------------------
631 checkNoErrs :: TcM r -> TcM r
632 -- (checkNoErrs m) succeeds iff m succeeds and generates no errors
633 -- If m fails then (checkNoErrsTc m) fails.
634 -- If m succeeds, it checks whether m generated any errors messages
635 -- (it might have recovered internally)
636 -- If so, it fails too.
637 -- Regardless, any errors generated by m are propagated to the enclosing context.
639 = do { (msgs, mb_res) <- tryTcLIE main
643 Just val -> return val
646 ifErrsM :: TcRn r -> TcRn r -> TcRn r
647 -- ifErrsM bale_out main
648 -- does 'bale_out' if there are errors in errors collection
649 -- otherwise does 'main'
650 ifErrsM bale_out normal
651 = do { errs_var <- getErrsVar ;
652 msgs <- readMutVar errs_var ;
654 if errorsFound dflags msgs then
659 failIfErrsM :: TcRn ()
660 -- Useful to avoid error cascades
661 failIfErrsM = ifErrsM failM (return ())
665 %************************************************************************
667 Context management and error message generation
670 %************************************************************************
673 getErrCtxt :: TcM ErrCtxt
674 getErrCtxt = do { env <- getLclEnv; return (tcl_ctxt env) }
676 setErrCtxt :: ErrCtxt -> TcM a -> TcM a
677 setErrCtxt ctxt = updLclEnv (\ env -> env { tcl_ctxt = ctxt })
679 addErrCtxt :: Message -> TcM a -> TcM a
680 addErrCtxt msg = addErrCtxtM (\env -> return (env, msg))
682 addErrCtxtM :: (TidyEnv -> TcM (TidyEnv, Message)) -> TcM a -> TcM a
683 addErrCtxtM msg = updCtxt (\ msgs -> msg : msgs)
685 -- Helper function for the above
686 updCtxt :: (ErrCtxt -> ErrCtxt) -> TcM a -> TcM a
687 updCtxt upd = updLclEnv (\ env@(TcLclEnv { tcl_ctxt = ctxt }) ->
688 env { tcl_ctxt = upd ctxt })
690 -- Conditionally add an error context
691 maybeAddErrCtxt :: Maybe Message -> TcM a -> TcM a
692 maybeAddErrCtxt (Just msg) thing_inside = addErrCtxt msg thing_inside
693 maybeAddErrCtxt Nothing thing_inside = thing_inside
695 popErrCtxt :: TcM a -> TcM a
696 popErrCtxt = updCtxt (\ msgs -> case msgs of { [] -> []; (_ : ms) -> ms })
698 getInstLoc :: InstOrigin -> TcM InstLoc
700 = do { loc <- getSrcSpanM ; env <- getLclEnv ;
701 return (InstLoc origin loc (tcl_ctxt env)) }
703 addInstCtxt :: InstLoc -> TcM a -> TcM a
704 -- Add the SrcSpan and context from the first Inst in the list
705 -- (they all have similar locations)
706 addInstCtxt (InstLoc _ src_loc ctxt) thing_inside
707 = setSrcSpan src_loc (updCtxt (\_ -> ctxt) thing_inside)
710 The addErrTc functions add an error message, but do not cause failure.
711 The 'M' variants pass a TidyEnv that has already been used to
712 tidy up the message; we then use it to tidy the context messages
715 addErrTc :: Message -> TcM ()
716 addErrTc err_msg = do { env0 <- tcInitTidyEnv
717 ; addErrTcM (env0, err_msg) }
719 addErrsTc :: [Message] -> TcM ()
720 addErrsTc err_msgs = mapM_ addErrTc err_msgs
722 addErrTcM :: (TidyEnv, Message) -> TcM ()
723 addErrTcM (tidy_env, err_msg)
724 = do { ctxt <- getErrCtxt ;
726 add_err_tcm tidy_env err_msg loc ctxt }
729 The failWith functions add an error message and cause failure
732 failWithTc :: Message -> TcM a -- Add an error message and fail
734 = addErrTc err_msg >> failM
736 failWithTcM :: (TidyEnv, Message) -> TcM a -- Add an error message and fail
737 failWithTcM local_and_msg
738 = addErrTcM local_and_msg >> failM
740 checkTc :: Bool -> Message -> TcM () -- Check that the boolean is true
741 checkTc True _ = return ()
742 checkTc False err = failWithTc err
745 Warnings have no 'M' variant, nor failure
748 addWarnTc :: Message -> TcM ()
749 addWarnTc msg = do { env0 <- tcInitTidyEnv
750 ; addWarnTcM (env0, msg) }
752 addWarnTcM :: (TidyEnv, Message) -> TcM ()
753 addWarnTcM (env0, msg)
754 = do { ctxt <- getErrCtxt ;
755 ctxt_msgs <- do_ctxt env0 ctxt ;
756 addReport (vcat (ptext (sLit "Warning:") <+> msg : ctxt_to_use ctxt_msgs)) }
758 warnTc :: Bool -> Message -> TcM ()
759 warnTc warn_if_true warn_msg
760 | warn_if_true = addWarnTc warn_msg
761 | otherwise = return ()
764 -----------------------------------
767 We initialise the "tidy-env", used for tidying types before printing,
768 by building a reverse map from the in-scope type variables to the
769 OccName that the programmer originally used for them
772 tcInitTidyEnv :: TcM TidyEnv
774 = do { lcl_env <- getLclEnv
775 ; let nm_tv_prs = [ (name, tcGetTyVar "tcInitTidyEnv" ty)
776 | ATyVar name ty <- nameEnvElts (tcl_env lcl_env)
778 ; return (foldl add emptyTidyEnv nm_tv_prs) }
780 add (env,subst) (name, tyvar)
781 = case tidyOccName env (nameOccName name) of
782 (env', occ') -> (env', extendVarEnv subst tyvar tyvar')
784 tyvar' = setTyVarName tyvar name'
785 name' = tidyNameOcc name occ'
788 -----------------------------------
789 Other helper functions
792 add_err_tcm :: TidyEnv -> Message -> SrcSpan
793 -> [TidyEnv -> TcM (TidyEnv, SDoc)]
795 add_err_tcm tidy_env err_msg loc ctxt
796 = do { ctxt_msgs <- do_ctxt tidy_env ctxt ;
797 addLongErrAt loc err_msg (vcat (ctxt_to_use ctxt_msgs)) }
799 do_ctxt :: TidyEnv -> [TidyEnv -> TcM (TidyEnv, SDoc)] -> TcM [SDoc]
802 do_ctxt tidy_env (c:cs)
803 = do { (tidy_env', m) <- c tidy_env ;
804 ms <- do_ctxt tidy_env' cs ;
807 ctxt_to_use :: [SDoc] -> [SDoc]
808 ctxt_to_use ctxt | opt_PprStyle_Debug = ctxt
809 | otherwise = take 3 ctxt
812 debugTc is useful for monadic debugging code
815 debugTc :: TcM () -> TcM ()
818 | otherwise = return ()
821 %************************************************************************
823 Type constraints (the so-called LIE)
825 %************************************************************************
828 nextDFunIndex :: TcM Int -- Get the next dfun index
829 nextDFunIndex = do { env <- getGblEnv
830 ; let dfun_n_var = tcg_dfun_n env
831 ; n <- readMutVar dfun_n_var
832 ; writeMutVar dfun_n_var (n+1)
835 getLIEVar :: TcM (TcRef LIE)
836 getLIEVar = do { env <- getLclEnv; return (tcl_lie env) }
838 setLIEVar :: TcRef LIE -> TcM a -> TcM a
839 setLIEVar lie_var = updLclEnv (\ env -> env { tcl_lie = lie_var })
841 getLIE :: TcM a -> TcM (a, [Inst])
842 -- (getLIE m) runs m, and returns the type constraints it generates
844 = do { lie_var <- newMutVar emptyLIE ;
845 res <- updLclEnv (\ env -> env { tcl_lie = lie_var })
847 lie <- readMutVar lie_var ;
848 return (res, lieToList lie) }
850 extendLIE :: Inst -> TcM ()
852 = do { lie_var <- getLIEVar ;
853 lie <- readMutVar lie_var ;
854 writeMutVar lie_var (inst `consLIE` lie) }
856 extendLIEs :: [Inst] -> TcM ()
860 = do { lie_var <- getLIEVar ;
861 lie <- readMutVar lie_var ;
862 writeMutVar lie_var (mkLIE insts `plusLIE` lie) }
866 setLclTypeEnv :: TcLclEnv -> TcM a -> TcM a
867 -- Set the local type envt, but do *not* disturb other fields,
868 -- notably the lie_var
869 setLclTypeEnv lcl_env thing_inside
870 = updLclEnv upd thing_inside
872 upd env = env { tcl_env = tcl_env lcl_env,
873 tcl_tyvars = tcl_tyvars lcl_env }
877 %************************************************************************
879 Template Haskell context
881 %************************************************************************
884 recordThUse :: TcM ()
885 recordThUse = do { env <- getGblEnv; writeMutVar (tcg_th_used env) True }
887 keepAliveTc :: Id -> TcM () -- Record the name in the keep-alive set
889 | isLocalId id = do { env <- getGblEnv;
890 ; updMutVar (tcg_keep env) (`addOneToNameSet` idName id) }
891 | otherwise = return ()
893 keepAliveSetTc :: NameSet -> TcM () -- Record the name in the keep-alive set
894 keepAliveSetTc ns = do { env <- getGblEnv;
895 ; updMutVar (tcg_keep env) (`unionNameSets` ns) }
897 getStage :: TcM ThStage
898 getStage = do { env <- getLclEnv; return (tcl_th_ctxt env) }
900 setStage :: ThStage -> TcM a -> TcM a
901 setStage s = updLclEnv (\ env -> env { tcl_th_ctxt = s })
905 %************************************************************************
907 Stuff for the renamer's local env
909 %************************************************************************
912 getLocalRdrEnv :: RnM LocalRdrEnv
913 getLocalRdrEnv = do { env <- getLclEnv; return (tcl_rdr env) }
915 setLocalRdrEnv :: LocalRdrEnv -> RnM a -> RnM a
916 setLocalRdrEnv rdr_env thing_inside
917 = updLclEnv (\env -> env {tcl_rdr = rdr_env}) thing_inside
921 %************************************************************************
923 Stuff for interface decls
925 %************************************************************************
928 mkIfLclEnv :: Module -> SDoc -> IfLclEnv
929 mkIfLclEnv mod loc = IfLclEnv { if_mod = mod,
931 if_tv_env = emptyUFM,
932 if_id_env = emptyUFM }
934 initIfaceTcRn :: IfG a -> TcRn a
935 initIfaceTcRn thing_inside
936 = do { tcg_env <- getGblEnv
937 ; let { if_env = IfGblEnv { if_rec_types = Just (tcg_mod tcg_env, get_type_env) }
938 ; get_type_env = readMutVar (tcg_type_env_var tcg_env) }
939 ; setEnvs (if_env, ()) thing_inside }
941 initIfaceExtCore :: IfL a -> TcRn a
942 initIfaceExtCore thing_inside
943 = do { tcg_env <- getGblEnv
944 ; let { mod = tcg_mod tcg_env
945 ; doc = ptext (sLit "External Core file for") <+> quotes (ppr mod)
946 ; if_env = IfGblEnv {
947 if_rec_types = Just (mod, return (tcg_type_env tcg_env)) }
948 ; if_lenv = mkIfLclEnv mod doc
950 ; setEnvs (if_env, if_lenv) thing_inside }
952 initIfaceCheck :: HscEnv -> IfG a -> IO a
953 -- Used when checking the up-to-date-ness of the old Iface
954 -- Initialise the environment with no useful info at all
955 initIfaceCheck hsc_env do_this
956 = do let rec_types = case hsc_type_env_var hsc_env of
957 Just (mod,var) -> Just (mod, readMutVar var)
959 gbl_env = IfGblEnv { if_rec_types = rec_types }
960 initTcRnIf 'i' hsc_env gbl_env () do_this
962 initIfaceTc :: ModIface
963 -> (TcRef TypeEnv -> IfL a) -> TcRnIf gbl lcl a
964 -- Used when type-checking checking an up-to-date interface file
965 -- No type envt from the current module, but we do know the module dependencies
966 initIfaceTc iface do_this
967 = do { tc_env_var <- newMutVar emptyTypeEnv
968 ; let { gbl_env = IfGblEnv { if_rec_types = Just (mod, readMutVar tc_env_var) } ;
969 ; if_lenv = mkIfLclEnv mod doc
971 ; setEnvs (gbl_env, if_lenv) (do_this tc_env_var)
974 mod = mi_module iface
975 doc = ptext (sLit "The interface for") <+> quotes (ppr mod)
977 initIfaceRules :: HscEnv -> ModGuts -> IfG a -> IO a
978 -- Used when sucking in new Rules in SimplCore
979 -- We have available the type envt of the module being compiled, and we must use it
980 initIfaceRules hsc_env guts do_this
982 type_info = (mg_module guts, return (mg_types guts))
983 ; gbl_env = IfGblEnv { if_rec_types = Just type_info } ;
986 -- Run the thing; any exceptions just bubble out from here
987 ; initTcRnIf 'i' hsc_env gbl_env () do_this
990 initIfaceLcl :: Module -> SDoc -> IfL a -> IfM lcl a
991 initIfaceLcl mod loc_doc thing_inside
992 = setLclEnv (mkIfLclEnv mod loc_doc) thing_inside
994 getIfModule :: IfL Module
995 getIfModule = do { env <- getLclEnv; return (if_mod env) }
998 failIfM :: Message -> IfL a
999 -- The Iface monad doesn't have a place to accumulate errors, so we
1000 -- just fall over fast if one happens; it "shouldnt happen".
1001 -- We use IfL here so that we can get context info out of the local env
1003 = do { env <- getLclEnv
1004 ; let full_msg = (if_loc env <> colon) $$ nest 2 msg
1005 ; liftIO (printErrs (full_msg defaultErrStyle))
1008 --------------------
1009 forkM_maybe :: SDoc -> IfL a -> IfL (Maybe a)
1010 -- Run thing_inside in an interleaved thread.
1011 -- It shares everything with the parent thread, so this is DANGEROUS.
1013 -- It returns Nothing if the computation fails
1015 -- It's used for lazily type-checking interface
1016 -- signatures, which is pretty benign
1018 forkM_maybe doc thing_inside
1019 = do { unsafeInterleaveM $
1020 do { traceIf (text "Starting fork {" <+> doc)
1022 updLclEnv (\env -> env { if_loc = if_loc env $$ doc }) $
1025 Right r -> do { traceIf (text "} ending fork" <+> doc)
1029 -- Bleat about errors in the forked thread, if -ddump-if-trace is on
1030 -- Otherwise we silently discard errors. Errors can legitimately
1031 -- happen when compiling interface signatures (see tcInterfaceSigs)
1032 ifOptM Opt_D_dump_if_trace
1033 (print_errs (hang (text "forkM failed:" <+> doc)
1034 4 (text (show exn))))
1036 ; traceIf (text "} ending fork (badly)" <+> doc)
1040 print_errs sdoc = liftIO (printErrs (sdoc defaultErrStyle))
1042 forkM :: SDoc -> IfL a -> IfL a
1043 forkM doc thing_inside
1044 = do { mb_res <- forkM_maybe doc thing_inside
1045 ; return (case mb_res of
1046 Nothing -> pgmError "Cannot continue after interface file error"
1047 -- pprPanic "forkM" doc