8 #include "HsVersions.h"
10 import TcRnTypes -- Re-export all
11 import IOEnv -- Re-export all
13 #if defined(GHCI) && defined(BREAKPOINT)
14 import TypeRep ( Type(..), liftedTypeKind )
15 import Var ( mkTyVar, mkGlobalId )
16 import IdInfo ( GlobalIdDetails(..), vanillaIdInfo )
17 import OccName ( mkOccName, tvName )
18 import SrcLoc ( noSrcLoc )
19 import TysWiredIn ( intTy, stringTy, mkListTy, unitTy, boolTy )
20 import PrelNames ( breakpointJumpName, breakpointCondJumpName )
21 import NameEnv ( mkNameEnv )
24 import HsSyn ( emptyLHsBinds )
25 import HscTypes ( HscEnv(..), ModGuts(..), ModIface(..),
26 TypeEnv, emptyTypeEnv, HscSource(..), isHsBoot,
27 ExternalPackageState(..), HomePackageTable,
28 Deprecs(..), FixityEnv, FixItem,
30 import Module ( Module, moduleName )
31 import RdrName ( GlobalRdrEnv, LocalRdrEnv, emptyLocalRdrEnv )
32 import Name ( Name, mkInternalName, tidyNameOcc, nameOccName, getSrcLoc )
34 import TcType ( tcIsTyVarTy, tcGetTyVar )
35 import NameEnv ( extendNameEnvList, nameEnvElts )
36 import InstEnv ( emptyInstEnv )
38 import Var ( setTyVarName )
39 import VarSet ( emptyVarSet )
40 import VarEnv ( TidyEnv, emptyTidyEnv, extendVarEnv )
41 import ErrUtils ( Message, Messages, emptyMessages, errorsFound,
42 mkWarnMsg, printErrorsAndWarnings,
43 mkLocMessage, mkLongErrMsg )
44 import SrcLoc ( mkGeneralSrcSpan, isGoodSrcSpan, SrcSpan, Located(..) )
45 import NameEnv ( emptyNameEnv )
46 import NameSet ( NameSet, emptyDUs, emptyNameSet, unionNameSets, addOneToNameSet )
47 import OccName ( emptyOccEnv, tidyOccName )
48 import Bag ( emptyBag )
50 import UniqSupply ( UniqSupply, mkSplitUniqSupply, uniqFromSupply, splitUniqSupply )
51 import UniqFM ( unitUFM )
52 import Unique ( Unique )
53 import DynFlags ( DynFlags(..), DynFlag(..), dopt, dopt_set, GhcMode )
54 import StaticFlags ( opt_PprStyle_Debug )
55 import Bag ( snocBag, unionBags )
56 import Panic ( showException )
59 import DATA_IOREF ( newIORef, readIORef )
60 import EXCEPTION ( Exception )
65 %************************************************************************
69 %************************************************************************
72 ioToTcRn :: IO r -> TcRn r
81 -> IO (Messages, Maybe r)
82 -- Nothing => error thrown by the thing inside
83 -- (error messages should have been printed already)
85 initTc hsc_env hsc_src mod do_this
86 = do { errs_var <- newIORef (emptyBag, emptyBag) ;
87 tvs_var <- newIORef emptyVarSet ;
88 type_env_var <- newIORef emptyNameEnv ;
89 dfuns_var <- newIORef emptyNameSet ;
90 keep_var <- newIORef emptyNameSet ;
91 th_var <- newIORef False ;
92 dfun_n_var <- newIORef 1 ;
97 tcg_rdr_env = hsc_global_rdr_env hsc_env,
98 tcg_fix_env = emptyNameEnv,
99 tcg_default = Nothing,
100 tcg_type_env = hsc_global_type_env hsc_env,
101 tcg_type_env_var = type_env_var,
102 tcg_inst_env = emptyInstEnv,
103 tcg_inst_uses = dfuns_var,
104 tcg_th_used = th_var,
105 tcg_exports = emptyNameSet,
106 tcg_imports = init_imports,
108 tcg_rn_imports = Nothing,
109 tcg_rn_exports = Nothing,
110 tcg_rn_decls = Nothing,
111 tcg_binds = emptyLHsBinds,
112 tcg_deprecs = NoDeprecs,
116 tcg_dfun_n = dfun_n_var,
121 tcl_loc = mkGeneralSrcSpan FSLIT("Top level"),
123 tcl_rdr = emptyLocalRdrEnv,
124 tcl_th_ctxt = topStage,
125 tcl_arrow_ctxt = NoArrowCtxt,
126 tcl_env = emptyNameEnv,
127 tcl_tyvars = tvs_var,
128 tcl_lie = panic "initTc:LIE" -- LIE only valid inside a getLIE
132 -- OK, here's the business end!
133 maybe_res <- initTcRnIf 'a' hsc_env gbl_env lcl_env $
135 #if defined(GHCI) && defined(BREAKPOINT)
136 unique <- newUnique ;
137 let { var = mkInternalName unique (mkOccName tvName "a") noSrcLoc;
138 tyvar = mkTyVar var liftedTypeKind;
139 basicType extra = (FunTy intTy
140 (FunTy (mkListTy unitTy)
144 (FunTy (TyVarTy tyvar)
145 (TyVarTy tyvar)))))));
147 = mkGlobalId VanillaGlobal breakpointJumpName
148 (basicType id) vanillaIdInfo;
149 breakpointCondJumpType
150 = mkGlobalId VanillaGlobal breakpointCondJumpName
151 (basicType (FunTy boolTy)) vanillaIdInfo;
152 new_env = mkNameEnv [(breakpointJumpName
153 , ATcId breakpointJumpType topLevel False)
154 ,(breakpointCondJumpName
155 , ATcId breakpointCondJumpType topLevel False)];
157 r <- tryM (updLclEnv (\gbl -> gbl{tcl_env=new_env}) do_this)
162 Right res -> return (Just res)
163 Left _ -> return Nothing } ;
165 -- Collect any error messages
166 msgs <- readIORef errs_var ;
168 let { dflags = hsc_dflags hsc_env
169 ; final_res | errorsFound dflags msgs = Nothing
170 | otherwise = maybe_res } ;
172 return (msgs, final_res)
175 init_imports = emptyImportAvails {imp_env =
176 unitUFM (moduleName mod) emptyNameSet}
177 -- Initialise tcg_imports with an empty set of bindings for
178 -- this module, so that if we see 'module M' in the export
179 -- list, and there are no bindings in M, we don't bleat
180 -- "unknown module M".
182 initTcPrintErrors -- Used from the interactive loop only
187 initTcPrintErrors env mod todo = do
188 (msgs, res) <- initTc env HsSrcFile mod todo
189 printErrorsAndWarnings (hsc_dflags env) msgs
194 %************************************************************************
198 %************************************************************************
202 initTcRnIf :: Char -- Tag for unique supply
207 initTcRnIf uniq_tag hsc_env gbl_env lcl_env thing_inside
208 = do { us <- mkSplitUniqSupply uniq_tag ;
209 ; us_var <- newIORef us ;
211 ; let { env = Env { env_top = hsc_env,
214 env_lcl = lcl_env } }
216 ; runIOEnv env thing_inside
220 %************************************************************************
224 %************************************************************************
227 getTopEnv :: TcRnIf gbl lcl HscEnv
228 getTopEnv = do { env <- getEnv; return (env_top env) }
230 getGblEnv :: TcRnIf gbl lcl gbl
231 getGblEnv = do { env <- getEnv; return (env_gbl env) }
233 updGblEnv :: (gbl -> gbl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
234 updGblEnv upd = updEnv (\ env@(Env { env_gbl = gbl }) ->
235 env { env_gbl = upd gbl })
237 setGblEnv :: gbl -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
238 setGblEnv gbl_env = updEnv (\ env -> env { env_gbl = gbl_env })
240 getLclEnv :: TcRnIf gbl lcl lcl
241 getLclEnv = do { env <- getEnv; return (env_lcl env) }
243 updLclEnv :: (lcl -> lcl) -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
244 updLclEnv upd = updEnv (\ env@(Env { env_lcl = lcl }) ->
245 env { env_lcl = upd lcl })
247 setLclEnv :: lcl' -> TcRnIf gbl lcl' a -> TcRnIf gbl lcl a
248 setLclEnv lcl_env = updEnv (\ env -> env { env_lcl = lcl_env })
250 getEnvs :: TcRnIf gbl lcl (gbl, lcl)
251 getEnvs = do { env <- getEnv; return (env_gbl env, env_lcl env) }
253 setEnvs :: (gbl', lcl') -> TcRnIf gbl' lcl' a -> TcRnIf gbl lcl a
254 setEnvs (gbl_env, lcl_env) = updEnv (\ env -> env { env_gbl = gbl_env, env_lcl = lcl_env })
261 getDOpts :: TcRnIf gbl lcl DynFlags
262 getDOpts = do { env <- getTopEnv; return (hsc_dflags env) }
264 doptM :: DynFlag -> TcRnIf gbl lcl Bool
265 doptM flag = do { dflags <- getDOpts; return (dopt flag dflags) }
267 setOptM :: DynFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
268 setOptM flag = updEnv (\ env@(Env { env_top = top }) ->
269 env { env_top = top { hsc_dflags = dopt_set (hsc_dflags top) flag}} )
271 ifOptM :: DynFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl () -- Do it flag is true
272 ifOptM flag thing_inside = do { b <- doptM flag;
273 if b then thing_inside else return () }
275 getGhcMode :: TcRnIf gbl lcl GhcMode
276 getGhcMode = do { env <- getTopEnv; return (ghcMode (hsc_dflags env)) }
280 getEpsVar :: TcRnIf gbl lcl (TcRef ExternalPackageState)
281 getEpsVar = do { env <- getTopEnv; return (hsc_EPS env) }
283 getEps :: TcRnIf gbl lcl ExternalPackageState
284 getEps = do { env <- getTopEnv; readMutVar (hsc_EPS env) }
286 -- Updating the EPS. This should be an atomic operation.
287 -- Note the delicate 'seq' which forces the EPS before putting it in the
288 -- variable. Otherwise what happens is that we get
289 -- write eps_var (....(unsafeRead eps_var)....)
290 -- and if the .... is strict, that's obviously bottom. By forcing it beforehand
291 -- we make the unsafeRead happen before we update the variable.
293 updateEps :: (ExternalPackageState -> (ExternalPackageState, a))
295 updateEps upd_fn = do { traceIf (text "updating EPS")
296 ; eps_var <- getEpsVar
297 ; eps <- readMutVar eps_var
298 ; let { (eps', val) = upd_fn eps }
299 ; seq eps' (writeMutVar eps_var eps')
302 updateEps_ :: (ExternalPackageState -> ExternalPackageState)
304 updateEps_ upd_fn = do { traceIf (text "updating EPS_")
305 ; eps_var <- getEpsVar
306 ; eps <- readMutVar eps_var
307 ; let { eps' = upd_fn eps }
308 ; seq eps' (writeMutVar eps_var eps') }
310 getHpt :: TcRnIf gbl lcl HomePackageTable
311 getHpt = do { env <- getTopEnv; return (hsc_HPT env) }
313 getEpsAndHpt :: TcRnIf gbl lcl (ExternalPackageState, HomePackageTable)
314 getEpsAndHpt = do { env <- getTopEnv; eps <- readMutVar (hsc_EPS env)
315 ; return (eps, hsc_HPT env) }
318 %************************************************************************
322 %************************************************************************
325 newUnique :: TcRnIf gbl lcl Unique
326 newUnique = do { us <- newUniqueSupply ;
327 return (uniqFromSupply us) }
329 newUniqueSupply :: TcRnIf gbl lcl UniqSupply
331 = do { env <- getEnv ;
332 let { u_var = env_us env } ;
333 us <- readMutVar u_var ;
334 let { (us1, us2) = splitUniqSupply us } ;
335 writeMutVar u_var us1 ;
338 newLocalName :: Name -> TcRnIf gbl lcl Name
339 newLocalName name -- Make a clone
340 = newUnique `thenM` \ uniq ->
341 returnM (mkInternalName uniq (nameOccName name) (getSrcLoc name))
345 %************************************************************************
349 %************************************************************************
352 traceTc, traceRn :: SDoc -> TcRn ()
353 traceRn = traceOptTcRn Opt_D_dump_rn_trace
354 traceTc = traceOptTcRn Opt_D_dump_tc_trace
355 traceSplice = traceOptTcRn Opt_D_dump_splices
358 traceIf :: SDoc -> TcRnIf m n ()
359 traceIf = traceOptIf Opt_D_dump_if_trace
360 traceHiDiffs = traceOptIf Opt_D_dump_hi_diffs
363 traceOptIf :: DynFlag -> SDoc -> TcRnIf m n () -- No RdrEnv available, so qualify everything
364 traceOptIf flag doc = ifOptM flag $
365 ioToIOEnv (printForUser stderr alwaysQualify doc)
367 traceOptTcRn :: DynFlag -> SDoc -> TcRn ()
368 traceOptTcRn flag doc = ifOptM flag $ do
371 ; env0 <- tcInitTidyEnv
372 ; ctxt_msgs <- do_ctxt env0 ctxt
373 ; let real_doc = mkLocMessage loc (vcat (doc : ctxt_to_use ctxt_msgs))
374 ; dumpTcRn real_doc }
376 dumpTcRn :: SDoc -> TcRn ()
377 dumpTcRn doc = do { rdr_env <- getGlobalRdrEnv ;
378 ioToTcRn (printForUser stderr (mkPrintUnqualified rdr_env) doc) }
380 dumpOptTcRn :: DynFlag -> SDoc -> TcRn ()
381 dumpOptTcRn flag doc = ifOptM flag (dumpTcRn doc)
385 %************************************************************************
387 Typechecker global environment
389 %************************************************************************
392 getModule :: TcRn Module
393 getModule = do { env <- getGblEnv; return (tcg_mod env) }
395 setModule :: Module -> TcRn a -> TcRn a
396 setModule mod thing_inside = updGblEnv (\env -> env { tcg_mod = mod }) thing_inside
398 tcIsHsBoot :: TcRn Bool
399 tcIsHsBoot = do { env <- getGblEnv; return (isHsBoot (tcg_src env)) }
401 getGlobalRdrEnv :: TcRn GlobalRdrEnv
402 getGlobalRdrEnv = do { env <- getGblEnv; return (tcg_rdr_env env) }
404 getImports :: TcRn ImportAvails
405 getImports = do { env <- getGblEnv; return (tcg_imports env) }
407 getFixityEnv :: TcRn FixityEnv
408 getFixityEnv = do { env <- getGblEnv; return (tcg_fix_env env) }
410 extendFixityEnv :: [(Name,FixItem)] -> RnM a -> RnM a
411 extendFixityEnv new_bit
412 = updGblEnv (\env@(TcGblEnv { tcg_fix_env = old_fix_env }) ->
413 env {tcg_fix_env = extendNameEnvList old_fix_env new_bit})
415 getDefaultTys :: TcRn (Maybe [Type])
416 getDefaultTys = do { env <- getGblEnv; return (tcg_default env) }
419 %************************************************************************
423 %************************************************************************
426 getSrcSpanM :: TcRn SrcSpan
427 -- Avoid clash with Name.getSrcLoc
428 getSrcSpanM = do { env <- getLclEnv; return (tcl_loc env) }
430 setSrcSpan :: SrcSpan -> TcRn a -> TcRn a
431 setSrcSpan loc thing_inside
432 | isGoodSrcSpan loc = updLclEnv (\env -> env { tcl_loc = loc }) thing_inside
433 | otherwise = thing_inside -- Don't overwrite useful info with useless
435 addLocM :: (a -> TcM b) -> Located a -> TcM b
436 addLocM fn (L loc a) = setSrcSpan loc $ fn a
438 wrapLocM :: (a -> TcM b) -> Located a -> TcM (Located b)
439 wrapLocM fn (L loc a) = setSrcSpan loc $ do b <- fn a; return (L loc b)
441 wrapLocFstM :: (a -> TcM (b,c)) -> Located a -> TcM (Located b, c)
442 wrapLocFstM fn (L loc a) =
447 wrapLocSndM :: (a -> TcM (b,c)) -> Located a -> TcM (b, Located c)
448 wrapLocSndM fn (L loc a) =
456 getErrsVar :: TcRn (TcRef Messages)
457 getErrsVar = do { env <- getLclEnv; return (tcl_errs env) }
459 setErrsVar :: TcRef Messages -> TcRn a -> TcRn a
460 setErrsVar v = updLclEnv (\ env -> env { tcl_errs = v })
462 addErr :: Message -> TcRn ()
463 addErr msg = do { loc <- getSrcSpanM ; addErrAt loc msg }
465 addLocErr :: Located e -> (e -> Message) -> TcRn ()
466 addLocErr (L loc e) fn = addErrAt loc (fn e)
468 addErrAt :: SrcSpan -> Message -> TcRn ()
469 addErrAt loc msg = addLongErrAt loc msg empty
471 addLongErrAt :: SrcSpan -> Message -> Message -> TcRn ()
472 addLongErrAt loc msg extra
473 = do { traceTc (ptext SLIT("Adding error:") <+> (mkLocMessage loc (msg $$ extra))) ;
474 errs_var <- getErrsVar ;
475 rdr_env <- getGlobalRdrEnv ;
476 let { err = mkLongErrMsg loc (mkPrintUnqualified rdr_env) msg extra } ;
477 (warns, errs) <- readMutVar errs_var ;
478 writeMutVar errs_var (warns, errs `snocBag` err) }
480 addErrs :: [(SrcSpan,Message)] -> TcRn ()
481 addErrs msgs = mappM_ add msgs
483 add (loc,msg) = addErrAt loc msg
485 addReport :: Message -> TcRn ()
486 addReport msg = do loc <- getSrcSpanM; addReportAt loc msg
488 addReportAt :: SrcSpan -> Message -> TcRn ()
490 = do { errs_var <- getErrsVar ;
491 rdr_env <- getGlobalRdrEnv ;
492 let { warn = mkWarnMsg loc (mkPrintUnqualified rdr_env) msg } ;
493 (warns, errs) <- readMutVar errs_var ;
494 writeMutVar errs_var (warns `snocBag` warn, errs) }
496 addWarn :: Message -> TcRn ()
497 addWarn msg = addReport (ptext SLIT("Warning:") <+> msg)
499 addWarnAt :: SrcSpan -> Message -> TcRn ()
500 addWarnAt loc msg = addReportAt loc (ptext SLIT("Warning:") <+> msg)
502 addLocWarn :: Located e -> (e -> Message) -> TcRn ()
503 addLocWarn (L loc e) fn = addReportAt loc (fn e)
505 checkErr :: Bool -> Message -> TcRn ()
506 -- Add the error if the bool is False
507 checkErr ok msg = checkM ok (addErr msg)
509 warnIf :: Bool -> Message -> TcRn ()
510 warnIf True msg = addWarn msg
511 warnIf False msg = return ()
513 addMessages :: Messages -> TcRn ()
514 addMessages (m_warns, m_errs)
515 = do { errs_var <- getErrsVar ;
516 (warns, errs) <- readMutVar errs_var ;
517 writeMutVar errs_var (warns `unionBags` m_warns,
518 errs `unionBags` m_errs) }
520 discardWarnings :: TcRn a -> TcRn a
521 -- Ignore warnings inside the thing inside;
522 -- used to ignore-unused-variable warnings inside derived code
523 -- With -dppr-debug, the effects is switched off, so you can still see
524 -- what warnings derived code would give
525 discardWarnings thing_inside
526 | opt_PprStyle_Debug = thing_inside
528 = do { errs_var <- newMutVar emptyMessages
529 ; result <- setErrsVar errs_var thing_inside
530 ; (_warns, errs) <- readMutVar errs_var
531 ; addMessages (emptyBag, errs)
537 try_m :: TcRn r -> TcRn (Either Exception r)
538 -- Does try_m, with a debug-trace on failure
540 = do { mb_r <- tryM thing ;
542 Left exn -> do { traceTc (exn_msg exn); return mb_r }
543 Right r -> return mb_r }
545 exn_msg exn = text "tryTc/recoverM recovering from" <+> text (showException exn)
547 -----------------------
548 recoverM :: TcRn r -- Recovery action; do this if the main one fails
549 -> TcRn r -- Main action: do this first
551 -- Errors in 'thing' are retained
552 recoverM recover thing
553 = do { mb_res <- try_m thing ;
556 Right res -> returnM res }
558 -----------------------
559 tryTc :: TcRn a -> TcRn (Messages, Maybe a)
560 -- (tryTc m) executes m, and returns
561 -- Just r, if m succeeds (returning r)
562 -- Nothing, if m fails
563 -- It also returns all the errors and warnings accumulated by m
564 -- It always succeeds (never raises an exception)
566 = do { errs_var <- newMutVar emptyMessages ;
567 res <- try_m (setErrsVar errs_var m) ;
568 msgs <- readMutVar errs_var ;
569 return (msgs, case res of
571 Right val -> Just val)
572 -- The exception is always the IOEnv built-in
573 -- in exception; see IOEnv.failM
576 -----------------------
577 tryTcErrs :: TcRn a -> TcRn (Messages, Maybe a)
578 -- Run the thing, returning
579 -- Just r, if m succceeds with no error messages
580 -- Nothing, if m fails, or if it succeeds but has error messages
581 -- Either way, the messages are returned; even in the Just case
582 -- there might be warnings
584 = do { (msgs, res) <- tryTc thing
586 ; let errs_found = errorsFound dflags msgs
587 ; return (msgs, case res of
589 Just val | errs_found -> Nothing
590 | otherwise -> Just val)
593 -----------------------
594 tryTcLIE :: TcM a -> TcM (Messages, Maybe a)
595 -- Just like tryTcErrs, except that it ensures that the LIE
596 -- for the thing is propagated only if there are no errors
597 -- Hence it's restricted to the type-check monad
598 tryTcLIE thing_inside
599 = do { ((msgs, mb_res), lie) <- getLIE (tryTcErrs thing_inside) ;
601 Nothing -> return (msgs, Nothing)
602 Just val -> do { extendLIEs lie; return (msgs, Just val) }
605 -----------------------
606 tryTcLIE_ :: TcM r -> TcM r -> TcM r
607 -- (tryTcLIE_ r m) tries m;
608 -- if m succeeds with no error messages, it's the answer
609 -- otherwise tryTcLIE_ drops everything from m and tries r instead.
610 tryTcLIE_ recover main
611 = do { (msgs, mb_res) <- tryTcLIE main
613 Just val -> do { addMessages msgs -- There might be warnings
615 Nothing -> recover -- Discard all msgs
618 -----------------------
619 checkNoErrs :: TcM r -> TcM r
620 -- (checkNoErrs m) succeeds iff m succeeds and generates no errors
621 -- If m fails then (checkNoErrsTc m) fails.
622 -- If m succeeds, it checks whether m generated any errors messages
623 -- (it might have recovered internally)
624 -- If so, it fails too.
625 -- Regardless, any errors generated by m are propagated to the enclosing context.
627 = do { (msgs, mb_res) <- tryTcLIE main
631 Just val -> return val
634 ifErrsM :: TcRn r -> TcRn r -> TcRn r
635 -- ifErrsM bale_out main
636 -- does 'bale_out' if there are errors in errors collection
637 -- otherwise does 'main'
638 ifErrsM bale_out normal
639 = do { errs_var <- getErrsVar ;
640 msgs <- readMutVar errs_var ;
642 if errorsFound dflags msgs then
647 failIfErrsM :: TcRn ()
648 -- Useful to avoid error cascades
649 failIfErrsM = ifErrsM failM (return ())
653 %************************************************************************
655 Context management and error message generation
658 %************************************************************************
661 getErrCtxt :: TcM ErrCtxt
662 getErrCtxt = do { env <- getLclEnv; return (tcl_ctxt env) }
664 setErrCtxt :: ErrCtxt -> TcM a -> TcM a
665 setErrCtxt ctxt = updLclEnv (\ env -> env { tcl_ctxt = ctxt })
667 addErrCtxt :: Message -> TcM a -> TcM a
668 addErrCtxt msg = addErrCtxtM (\env -> returnM (env, msg))
670 addErrCtxtM :: (TidyEnv -> TcM (TidyEnv, Message)) -> TcM a -> TcM a
671 addErrCtxtM msg = updCtxt (\ msgs -> msg : msgs)
673 -- Helper function for the above
674 updCtxt :: (ErrCtxt -> ErrCtxt) -> TcM a -> TcM a
675 updCtxt upd = updLclEnv (\ env@(TcLclEnv { tcl_ctxt = ctxt }) ->
676 env { tcl_ctxt = upd ctxt })
678 -- Conditionally add an error context
679 maybeAddErrCtxt :: Maybe Message -> TcM a -> TcM a
680 maybeAddErrCtxt (Just msg) thing_inside = addErrCtxt msg thing_inside
681 maybeAddErrCtxt Nothing thing_inside = thing_inside
683 popErrCtxt :: TcM a -> TcM a
684 popErrCtxt = updCtxt (\ msgs -> case msgs of { [] -> []; (m:ms) -> ms })
686 getInstLoc :: InstOrigin -> TcM InstLoc
688 = do { loc <- getSrcSpanM ; env <- getLclEnv ;
689 return (InstLoc origin loc (tcl_ctxt env)) }
691 addInstCtxt :: InstLoc -> TcM a -> TcM a
692 -- Add the SrcSpan and context from the first Inst in the list
693 -- (they all have similar locations)
694 addInstCtxt (InstLoc _ src_loc ctxt) thing_inside
695 = setSrcSpan src_loc (updCtxt (\ old_ctxt -> ctxt) thing_inside)
698 The addErrTc functions add an error message, but do not cause failure.
699 The 'M' variants pass a TidyEnv that has already been used to
700 tidy up the message; we then use it to tidy the context messages
703 addErrTc :: Message -> TcM ()
704 addErrTc err_msg = do { env0 <- tcInitTidyEnv
705 ; addErrTcM (env0, err_msg) }
707 addErrsTc :: [Message] -> TcM ()
708 addErrsTc err_msgs = mappM_ addErrTc err_msgs
710 addErrTcM :: (TidyEnv, Message) -> TcM ()
711 addErrTcM (tidy_env, err_msg)
712 = do { ctxt <- getErrCtxt ;
714 add_err_tcm tidy_env err_msg loc ctxt }
717 The failWith functions add an error message and cause failure
720 failWithTc :: Message -> TcM a -- Add an error message and fail
722 = addErrTc err_msg >> failM
724 failWithTcM :: (TidyEnv, Message) -> TcM a -- Add an error message and fail
725 failWithTcM local_and_msg
726 = addErrTcM local_and_msg >> failM
728 checkTc :: Bool -> Message -> TcM () -- Check that the boolean is true
729 checkTc True err = returnM ()
730 checkTc False err = failWithTc err
733 Warnings have no 'M' variant, nor failure
736 addWarnTc :: Message -> TcM ()
738 = do { ctxt <- getErrCtxt ;
739 env0 <- tcInitTidyEnv ;
740 ctxt_msgs <- do_ctxt env0 ctxt ;
741 addWarn (vcat (msg : ctxt_to_use ctxt_msgs)) }
743 warnTc :: Bool -> Message -> TcM ()
744 warnTc warn_if_true warn_msg
745 | warn_if_true = addWarnTc warn_msg
746 | otherwise = return ()
749 -----------------------------------
752 We initialise the "tidy-env", used for tidying types before printing,
753 by building a reverse map from the in-scope type variables to the
754 OccName that the programmer originally used for them
757 tcInitTidyEnv :: TcM TidyEnv
759 = do { lcl_env <- getLclEnv
760 ; let nm_tv_prs = [ (name, tcGetTyVar "tcInitTidyEnv" ty)
761 | ATyVar name ty <- nameEnvElts (tcl_env lcl_env)
763 ; return (foldl add emptyTidyEnv nm_tv_prs) }
765 add (env,subst) (name, tyvar)
766 = case tidyOccName env (nameOccName name) of
767 (env', occ') -> (env', extendVarEnv subst tyvar tyvar')
769 tyvar' = setTyVarName tyvar name'
770 name' = tidyNameOcc name occ'
773 -----------------------------------
774 Other helper functions
777 add_err_tcm tidy_env err_msg loc ctxt
778 = do { ctxt_msgs <- do_ctxt tidy_env ctxt ;
779 addLongErrAt loc err_msg (vcat (ctxt_to_use ctxt_msgs)) }
783 do_ctxt tidy_env (c:cs)
784 = do { (tidy_env', m) <- c tidy_env ;
785 ms <- do_ctxt tidy_env' cs ;
788 ctxt_to_use ctxt | opt_PprStyle_Debug = ctxt
789 | otherwise = take 3 ctxt
792 debugTc is useful for monadic debugging code
795 debugTc :: TcM () -> TcM ()
797 debugTc thing = thing
799 debugTc thing = return ()
803 %************************************************************************
805 Type constraints (the so-called LIE)
807 %************************************************************************
810 nextDFunIndex :: TcM Int -- Get the next dfun index
811 nextDFunIndex = do { env <- getGblEnv
812 ; let dfun_n_var = tcg_dfun_n env
813 ; n <- readMutVar dfun_n_var
814 ; writeMutVar dfun_n_var (n+1)
817 getLIEVar :: TcM (TcRef LIE)
818 getLIEVar = do { env <- getLclEnv; return (tcl_lie env) }
820 setLIEVar :: TcRef LIE -> TcM a -> TcM a
821 setLIEVar lie_var = updLclEnv (\ env -> env { tcl_lie = lie_var })
823 getLIE :: TcM a -> TcM (a, [Inst])
824 -- (getLIE m) runs m, and returns the type constraints it generates
826 = do { lie_var <- newMutVar emptyLIE ;
827 res <- updLclEnv (\ env -> env { tcl_lie = lie_var })
829 lie <- readMutVar lie_var ;
830 return (res, lieToList lie) }
832 extendLIE :: Inst -> TcM ()
834 = do { lie_var <- getLIEVar ;
835 lie <- readMutVar lie_var ;
836 writeMutVar lie_var (inst `consLIE` lie) }
838 extendLIEs :: [Inst] -> TcM ()
842 = do { lie_var <- getLIEVar ;
843 lie <- readMutVar lie_var ;
844 writeMutVar lie_var (mkLIE insts `plusLIE` lie) }
848 setLclTypeEnv :: TcLclEnv -> TcM a -> TcM a
849 -- Set the local type envt, but do *not* disturb other fields,
850 -- notably the lie_var
851 setLclTypeEnv lcl_env thing_inside
852 = updLclEnv upd thing_inside
854 upd env = env { tcl_env = tcl_env lcl_env,
855 tcl_tyvars = tcl_tyvars lcl_env }
859 %************************************************************************
861 Template Haskell context
863 %************************************************************************
866 recordThUse :: TcM ()
867 recordThUse = do { env <- getGblEnv; writeMutVar (tcg_th_used env) True }
869 keepAliveTc :: Name -> TcM () -- Record the name in the keep-alive set
870 keepAliveTc n = do { env <- getGblEnv;
871 ; updMutVar (tcg_keep env) (`addOneToNameSet` n) }
873 keepAliveSetTc :: NameSet -> TcM () -- Record the name in the keep-alive set
874 keepAliveSetTc ns = do { env <- getGblEnv;
875 ; updMutVar (tcg_keep env) (`unionNameSets` ns) }
877 getStage :: TcM ThStage
878 getStage = do { env <- getLclEnv; return (tcl_th_ctxt env) }
880 setStage :: ThStage -> TcM a -> TcM a
881 setStage s = updLclEnv (\ env -> env { tcl_th_ctxt = s })
885 %************************************************************************
887 Stuff for the renamer's local env
889 %************************************************************************
892 getLocalRdrEnv :: RnM LocalRdrEnv
893 getLocalRdrEnv = do { env <- getLclEnv; return (tcl_rdr env) }
895 setLocalRdrEnv :: LocalRdrEnv -> RnM a -> RnM a
896 setLocalRdrEnv rdr_env thing_inside
897 = updLclEnv (\env -> env {tcl_rdr = rdr_env}) thing_inside
901 %************************************************************************
903 Stuff for interface decls
905 %************************************************************************
908 mkIfLclEnv :: Module -> SDoc -> IfLclEnv
909 mkIfLclEnv mod loc = IfLclEnv { if_mod = mod,
911 if_tv_env = emptyOccEnv,
912 if_id_env = emptyOccEnv }
914 initIfaceTcRn :: IfG a -> TcRn a
915 initIfaceTcRn thing_inside
916 = do { tcg_env <- getGblEnv
917 ; let { if_env = IfGblEnv { if_rec_types = Just (tcg_mod tcg_env, get_type_env) }
918 ; get_type_env = readMutVar (tcg_type_env_var tcg_env) }
919 ; setEnvs (if_env, ()) thing_inside }
921 initIfaceExtCore :: IfL a -> TcRn a
922 initIfaceExtCore thing_inside
923 = do { tcg_env <- getGblEnv
924 ; let { mod = tcg_mod tcg_env
925 ; doc = ptext SLIT("External Core file for") <+> quotes (ppr mod)
926 ; if_env = IfGblEnv {
927 if_rec_types = Just (mod, return (tcg_type_env tcg_env)) }
928 ; if_lenv = mkIfLclEnv mod doc
930 ; setEnvs (if_env, if_lenv) thing_inside }
932 initIfaceCheck :: HscEnv -> IfG a -> IO a
933 -- Used when checking the up-to-date-ness of the old Iface
934 -- Initialise the environment with no useful info at all
935 initIfaceCheck hsc_env do_this
936 = do { let gbl_env = IfGblEnv { if_rec_types = Nothing }
937 ; initTcRnIf 'i' hsc_env gbl_env () do_this
940 initIfaceTc :: ModIface
941 -> (TcRef TypeEnv -> IfL a) -> TcRnIf gbl lcl a
942 -- Used when type-checking checking an up-to-date interface file
943 -- No type envt from the current module, but we do know the module dependencies
944 initIfaceTc iface do_this
945 = do { tc_env_var <- newMutVar emptyTypeEnv
946 ; let { gbl_env = IfGblEnv { if_rec_types = Just (mod, readMutVar tc_env_var) } ;
947 ; if_lenv = mkIfLclEnv mod doc
949 ; setEnvs (gbl_env, if_lenv) (do_this tc_env_var)
952 mod = mi_module iface
953 doc = ptext SLIT("The interface for") <+> quotes (ppr mod)
955 initIfaceRules :: HscEnv -> ModGuts -> IfG a -> IO a
956 -- Used when sucking in new Rules in SimplCore
957 -- We have available the type envt of the module being compiled, and we must use it
958 initIfaceRules hsc_env guts do_this
960 type_info = (mg_module guts, return (mg_types guts))
961 ; gbl_env = IfGblEnv { if_rec_types = Just type_info } ;
964 -- Run the thing; any exceptions just bubble out from here
965 ; initTcRnIf 'i' hsc_env gbl_env () do_this
968 initIfaceLcl :: Module -> SDoc -> IfL a -> IfM lcl a
969 initIfaceLcl mod loc_doc thing_inside
970 = setLclEnv (mkIfLclEnv mod loc_doc) thing_inside
972 getIfModule :: IfL Module
973 getIfModule = do { env <- getLclEnv; return (if_mod env) }
976 failIfM :: Message -> IfL a
977 -- The Iface monad doesn't have a place to accumulate errors, so we
978 -- just fall over fast if one happens; it "shouldnt happen".
979 -- We use IfL here so that we can get context info out of the local env
981 = do { env <- getLclEnv
982 ; let full_msg = (if_loc env <> colon) $$ nest 2 msg
983 ; ioToIOEnv (printErrs (full_msg defaultErrStyle))
987 forkM_maybe :: SDoc -> IfL a -> IfL (Maybe a)
988 -- Run thing_inside in an interleaved thread.
989 -- It shares everything with the parent thread, so this is DANGEROUS.
991 -- It returns Nothing if the computation fails
993 -- It's used for lazily type-checking interface
994 -- signatures, which is pretty benign
996 forkM_maybe doc thing_inside
997 = do { unsafeInterleaveM $
998 do { traceIf (text "Starting fork {" <+> doc)
1000 updLclEnv (\env -> env { if_loc = if_loc env $$ doc }) $
1003 Right r -> do { traceIf (text "} ending fork" <+> doc)
1007 -- Bleat about errors in the forked thread, if -ddump-if-trace is on
1008 -- Otherwise we silently discard errors. Errors can legitimately
1009 -- happen when compiling interface signatures (see tcInterfaceSigs)
1010 ifOptM Opt_D_dump_if_trace
1011 (print_errs (hang (text "forkM failed:" <+> doc)
1012 4 (text (show exn))))
1014 ; traceIf (text "} ending fork (badly)" <+> doc)
1018 print_errs sdoc = ioToIOEnv (printErrs (sdoc defaultErrStyle))
1020 forkM :: SDoc -> IfL a -> IfL a
1021 forkM doc thing_inside
1022 = do { mb_res <- forkM_maybe doc thing_inside
1023 ; return (case mb_res of
1024 Nothing -> pgmError "Cannot continue after interface file error"
1025 -- pprPanic "forkM" doc