4 TcTauType, TcThetaType, TcRhoType,
8 TcM, NF_TcM, TcDown, TcEnv,
11 returnTc, thenTc, thenTc_, mapTc, listTc,
12 foldrTc, foldlTc, mapAndUnzipTc, mapAndUnzip3Tc,
13 mapBagTc, fixTc, tryTc, tryTc_, getErrsTc,
18 returnNF_Tc, thenNF_Tc, thenNF_Tc_, mapNF_Tc,
19 fixNF_Tc, forkNF_Tc, foldrNF_Tc, foldlNF_Tc,
21 listNF_Tc, mapAndUnzipNF_Tc, mapBagNF_Tc,
23 checkTc, checkTcM, checkMaybeTc, checkMaybeTcM,
24 failTc, failWithTc, addErrTc, warnTc, recoverTc, checkNoErrsTc, recoverNF_Tc, discardErrsTc,
25 addErrTcM, addInstErrTcM, failWithTcM,
28 tcGetDefaultTys, tcSetDefaultTys,
29 tcGetUnique, tcGetUniques,
31 tcAddSrcLoc, tcGetSrcLoc, tcGetInstLoc,
32 tcAddErrCtxtM, tcSetErrCtxtM,
33 tcAddErrCtxt, tcSetErrCtxt,
35 tcNewMutVar, tcNewSigTyVar, tcReadMutVar, tcWriteMutVar, TcRef,
36 tcNewMutTyVar, tcReadMutTyVar, tcWriteMutTyVar,
38 InstOrigin(..), InstLoc, pprInstLoc,
40 TcError, TcWarning, TidyEnv, emptyTidyEnv,
44 #include "HsVersions.h"
46 import {-# SOURCE #-} TcEnv ( TcEnv )
48 import HsSyn ( HsLit )
49 import RnHsSyn ( RenamedPat, RenamedArithSeqInfo, RenamedHsExpr )
50 import Type ( Type, Kind, ThetaType, RhoType, TauType,
52 import ErrUtils ( addShortErrLocLine, addShortWarnLocLine, pprBagOfErrors, ErrMsg, Message, WarnMsg )
53 import CmdLineOpts ( opt_PprStyle_Debug )
55 import Bag ( Bag, emptyBag, isEmptyBag,
56 foldBag, unitBag, unionBags, snocBag )
57 import Class ( Class )
59 import Var ( Id, TyVar, newMutTyVar, newSigTyVar, readMutTyVar, writeMutTyVar )
60 import VarEnv ( TyVarEnv, emptyVarEnv, TidyEnv, emptyTidyEnv )
61 import VarSet ( TyVarSet )
62 import UniqSupply ( UniqSupply, uniqFromSupply, uniqsFromSupply, splitUniqSupply,
64 import SrcLoc ( SrcLoc, noSrcLoc )
65 import FiniteMap ( FiniteMap, emptyFM )
66 import UniqFM ( UniqFM, emptyUFM )
67 import Unique ( Unique )
68 import BasicTypes ( Unused )
71 import FastString ( FastString )
73 import IOExts ( IORef, newIORef, readIORef, writeIORef,
74 unsafeInterleaveIO, fixIO
78 infixr 9 `thenTc`, `thenTc_`, `thenNF_Tc`, `thenNF_Tc_`
85 type TcTyVar = TyVar -- Might be a mutable tyvar
86 type TcTyVarSet = TyVarSet
88 type TcType = Type -- A TcType can have mutable type variables
89 -- Invariant on ForAllTy in TcTypes:
91 -- a cannot occur inside a MutTyVar in T; that is,
92 -- T is "flattened" before quantifying over a
94 type TcThetaType = ThetaType
95 type TcRhoType = RhoType
96 type TcTauType = TauType
101 \section{TcM, NF_TcM: the type checker monads}
102 %~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
105 type NF_TcM s r = TcDown -> TcEnv -> IO r -- Can't raise UserError
106 type TcM s r = TcDown -> TcEnv -> IO r -- Can raise UserError
107 -- ToDo: nuke the 's' part
108 -- The difference between the two is
109 -- now for documentation purposes only
111 type Either_TcM s r = TcDown -> TcEnv -> IO r -- Either NF_TcM or TcM
112 -- Used only in this file for type signatures which
113 -- have a part that's polymorphic in whether it's NF_TcM or TcM
116 type TcRef a = IORef a
120 -- initEnv is passed in to avoid module recursion between TcEnv & TcMonad.
123 -> (TcRef (UniqFM a) -> TcEnv)
125 -> IO (Maybe r, Bag WarnMsg, Bag ErrMsg)
127 initTc us initenv do_this
129 us_var <- newIORef us ;
130 errs_var <- newIORef (emptyBag,emptyBag) ;
131 tvs_var <- newIORef emptyUFM ;
134 init_down = TcDown [] us_var
137 init_env = initenv tvs_var
140 maybe_res <- catch (do { res <- do_this init_down init_env ;
142 (\_ -> return Nothing) ;
144 (warns,errs) <- readIORef errs_var ;
145 return (maybe_res, warns, errs)
148 -- Monadic operations
150 returnNF_Tc :: a -> NF_TcM s a
151 returnTc :: a -> TcM s a
152 returnTc v down env = return v
154 thenTc :: TcM s a -> (a -> TcM s b) -> TcM s b
155 thenNF_Tc :: NF_TcM s a -> (a -> Either_TcM s b) -> Either_TcM s b
156 thenTc m k down env = do { r <- m down env; k r down env }
158 thenTc_ :: TcM s a -> TcM s b -> TcM s b
159 thenNF_Tc_ :: NF_TcM s a -> Either_TcM s b -> Either_TcM s b
160 thenTc_ m k down env = do { m down env; k down env }
162 listTc :: [TcM s a] -> TcM s [a]
163 listNF_Tc :: [NF_TcM s a] -> NF_TcM s [a]
164 listTc [] = returnTc []
165 listTc (x:xs) = x `thenTc` \ r ->
166 listTc xs `thenTc` \ rs ->
169 mapTc :: (a -> TcM s b) -> [a] -> TcM s [b]
170 mapNF_Tc :: (a -> NF_TcM s b) -> [a] -> NF_TcM s [b]
171 mapTc f [] = returnTc []
172 mapTc f (x:xs) = f x `thenTc` \ r ->
173 mapTc f xs `thenTc` \ rs ->
176 foldrTc :: (a -> b -> TcM s b) -> b -> [a] -> TcM s b
177 foldrNF_Tc :: (a -> b -> NF_TcM s b) -> b -> [a] -> NF_TcM s b
178 foldrTc k z [] = returnTc z
179 foldrTc k z (x:xs) = foldrTc k z xs `thenTc` \r ->
182 foldlTc :: (a -> b -> TcM s a) -> a -> [b] -> TcM s a
183 foldlNF_Tc :: (a -> b -> NF_TcM s a) -> a -> [b] -> NF_TcM s a
184 foldlTc k z [] = returnTc z
185 foldlTc k z (x:xs) = k z x `thenTc` \r ->
188 mapAndUnzipTc :: (a -> TcM s (b,c)) -> [a] -> TcM s ([b],[c])
189 mapAndUnzipNF_Tc :: (a -> NF_TcM s (b,c)) -> [a] -> NF_TcM s ([b],[c])
190 mapAndUnzipTc f [] = returnTc ([],[])
191 mapAndUnzipTc f (x:xs) = f x `thenTc` \ (r1,r2) ->
192 mapAndUnzipTc f xs `thenTc` \ (rs1,rs2) ->
193 returnTc (r1:rs1, r2:rs2)
195 mapAndUnzip3Tc :: (a -> TcM s (b,c,d)) -> [a] -> TcM s ([b],[c],[d])
196 mapAndUnzip3Tc f [] = returnTc ([],[],[])
197 mapAndUnzip3Tc f (x:xs) = f x `thenTc` \ (r1,r2,r3) ->
198 mapAndUnzip3Tc f xs `thenTc` \ (rs1,rs2,rs3) ->
199 returnTc (r1:rs1, r2:rs2, r3:rs3)
201 mapBagTc :: (a -> TcM s b) -> Bag a -> TcM s (Bag b)
202 mapBagNF_Tc :: (a -> NF_TcM s b) -> Bag a -> NF_TcM s (Bag b)
204 = foldBag (\ b1 b2 -> b1 `thenTc` \ r1 ->
206 returnTc (unionBags r1 r2))
207 (\ a -> f a `thenTc` \ r -> returnTc (unitBag r))
211 fixTc :: (a -> TcM s a) -> TcM s a
212 fixNF_Tc :: (a -> NF_TcM s a) -> NF_TcM s a
213 fixTc m env down = fixIO (\ loop -> m loop env down)
215 recoverTc :: TcM s r -> TcM s r -> TcM s r
216 recoverNF_Tc :: NF_TcM s r -> TcM s r -> NF_TcM s r
217 recoverTc recover m down env
218 = catch (m down env) (\ _ -> recover down env)
220 returnNF_Tc = returnTc
224 recoverNF_Tc = recoverTc
229 mapAndUnzipNF_Tc = mapAndUnzipTc
230 mapBagNF_Tc = mapBagTc
233 @forkNF_Tc@ runs a sub-typecheck action *lazily* in a separate state
234 thread. Ideally, this elegantly ensures that it can't zap any type
235 variables that belong to the main thread. But alas, the environment
236 contains TyCon and Class environments that include TcKind stuff,
237 which is a Royal Pain. By the time this fork stuff is used they'll
238 have been unified down so there won't be any kind variables, but we
239 can't express that in the current typechecker framework.
241 So we compromise and use unsafeInterleaveSST.
243 We throw away any error messages!
246 forkNF_Tc :: NF_TcM s r -> NF_TcM s r
247 forkNF_Tc m (TcDown deflts u_var src_loc err_cxt err_var) env
249 -- Get a fresh unique supply
250 us <- readIORef u_var
251 let (us1, us2) = splitUniqSupply us
254 unsafeInterleaveIO (do {
255 us_var' <- newIORef us2 ;
256 err_var' <- newIORef (emptyBag,emptyBag) ;
257 tv_var' <- newIORef emptyUFM ;
258 let { down' = TcDown deflts us_var' src_loc err_cxt err_var' } ;
260 -- ToDo: optionally dump any error messages
265 traceTc :: SDoc -> NF_TcM s ()
266 traceTc doc down env = printErrs doc
268 ioToTc :: IO a -> NF_TcM s a
269 ioToTc io down env = io
273 %************************************************************************
275 \subsection{Error handling}
277 %************************************************************************
280 getErrsTc :: NF_TcM s (Bag WarnMsg, Bag ErrMsg)
282 = readIORef (getTcErrs down)
285 failTc down env = give_up
288 give_up = IOERROR (userError "Typecheck failed")
290 failWithTc :: Message -> TcM s a -- Add an error message and fail
291 failWithTc err_msg = failWithTcM (emptyTidyEnv, err_msg)
293 addErrTc :: Message -> NF_TcM s ()
294 addErrTc err_msg = addErrTcM (emptyTidyEnv, err_msg)
296 -- The 'M' variants do the TidyEnv bit
297 failWithTcM :: (TidyEnv, Message) -> TcM s a -- Add an error message and fail
298 failWithTcM env_and_msg
299 = addErrTcM env_and_msg `thenNF_Tc_`
302 checkTc :: Bool -> Message -> TcM s () -- Check that the boolean is true
303 checkTc True err = returnTc ()
304 checkTc False err = failWithTc err
306 checkTcM :: Bool -> TcM s () -> TcM s () -- Check that the boolean is true
307 checkTcM True err = returnTc ()
308 checkTcM False err = err
310 checkMaybeTc :: Maybe val -> Message -> TcM s val
311 checkMaybeTc (Just val) err = returnTc val
312 checkMaybeTc Nothing err = failWithTc err
314 checkMaybeTcM :: Maybe val -> TcM s val -> TcM s val
315 checkMaybeTcM (Just val) err = returnTc val
316 checkMaybeTcM Nothing err = err
318 addErrTcM :: (TidyEnv, Message) -> NF_TcM s () -- Add an error message but don't fail
319 addErrTcM (tidy_env, err_msg) down env
320 = add_err_tcm tidy_env err_msg ctxt loc down env
322 ctxt = getErrCtxt down
325 addInstErrTcM :: InstLoc -> (TidyEnv, Message) -> NF_TcM s () -- Add an error message but don't fail
326 addInstErrTcM inst_loc@(_, loc, ctxt) (tidy_env, err_msg) down env
327 = add_err_tcm tidy_env err_msg full_ctxt loc down env
329 full_ctxt = (\env -> returnNF_Tc (env, pprInstLoc inst_loc)) : ctxt
331 add_err_tcm tidy_env err_msg ctxt loc down env
333 (warns, errs) <- readIORef errs_var
334 ctxt_msgs <- do_ctxt tidy_env ctxt down env
335 let err = addShortErrLocLine loc $
336 vcat (err_msg : ctxt_to_use ctxt_msgs)
337 writeIORef errs_var (warns, errs `snocBag` err)
339 errs_var = getTcErrs down
341 do_ctxt tidy_env [] down env
343 do_ctxt tidy_env (c:cs) down env
345 (tidy_env', m) <- c tidy_env down env
346 ms <- do_ctxt tidy_env' cs down env
349 -- warnings don't have an 'M' variant
350 warnTc :: Bool -> Message -> NF_TcM s ()
351 warnTc warn_if_true warn_msg down env
354 (warns,errs) <- readIORef errs_var
355 ctxt_msgs <- do_ctxt emptyTidyEnv ctxt down env
356 let warn = addShortWarnLocLine loc $
357 vcat (warn_msg : ctxt_to_use ctxt_msgs)
358 writeIORef errs_var (warns `snocBag` warn, errs)
362 errs_var = getTcErrs down
363 ctxt = getErrCtxt down
366 -- (tryTc r m) succeeds if m succeeds and generates no errors
367 -- If m fails then r is invoked, passing the warnings and errors from m
368 -- If m succeeds, (tryTc r m) checks whether m generated any errors messages
369 -- (it might have recovered internally)
370 -- If so, then r is invoked, passing the warnings and errors from m
372 tryTc :: ((Bag WarnMsg, Bag ErrMsg) -> TcM s r) -- Recovery action
373 -> TcM s r -- Thing to try
375 tryTc recover main down env
377 m_errs_var <- newIORef (emptyBag,emptyBag)
378 catch (my_main m_errs_var) (\ _ -> my_recover m_errs_var)
380 my_recover m_errs_var
381 = do warns_and_errs <- readIORef m_errs_var
382 recover warns_and_errs down env
385 = do result <- main (setTcErrs down m_errs_var) env
387 -- Check that m has no errors; if it has internal recovery
388 -- mechanisms it might "succeed" but having found a bunch of
389 -- errors along the way.
390 (m_warns, m_errs) <- readIORef m_errs_var
391 if isEmptyBag m_errs then
394 give_up -- This triggers the catch
397 -- (checkNoErrsTc m) succeeds iff m succeeds and generates no errors
398 -- If m fails then (checkNoErrsTc m) fails.
399 -- If m succeeds, it checks whether m generated any errors messages
400 -- (it might have recovered internally)
401 -- If so, it fails too.
402 -- Regardless, any errors generated by m are propagated to the enclosing context.
403 checkNoErrsTc :: TcM s r -> TcM s r
405 = tryTc my_recover main
407 my_recover (m_warns, m_errs) down env
408 = do (warns, errs) <- readIORef errs_var
409 writeIORef errs_var (warns `unionBags` m_warns,
410 errs `unionBags` m_errs)
413 errs_var = getTcErrs down
416 -- (tryTc_ r m) tries m; if it succeeds it returns it,
417 -- otherwise it returns r. Any error messages added by m are discarded,
418 -- whether or not m succeeds.
419 tryTc_ :: TcM s r -> TcM s r -> TcM s r
421 = tryTc my_recover main
423 my_recover warns_and_errs = recover
425 -- (discardErrsTc m) runs m, but throw away all its error messages.
426 discardErrsTc :: Either_TcM s r -> Either_TcM s r
427 discardErrsTc main down env
428 = do new_errs_var <- newIORef (emptyBag,emptyBag)
429 main (setTcErrs down new_errs_var) env
435 tcNewMutVar :: a -> NF_TcM s (TcRef a)
436 tcNewMutVar val down env = newIORef val
438 tcWriteMutVar :: TcRef a -> a -> NF_TcM s ()
439 tcWriteMutVar var val down env = writeIORef var val
441 tcReadMutVar :: TcRef a -> NF_TcM s a
442 tcReadMutVar var down env = readIORef var
444 tcNewMutTyVar :: Name -> Kind -> NF_TcM s TyVar
445 tcNewMutTyVar name kind down env = newMutTyVar name kind
447 tcNewSigTyVar :: Name -> Kind -> NF_TcM s TyVar
448 tcNewSigTyVar name kind down env = newSigTyVar name kind
450 tcReadMutTyVar :: TyVar -> NF_TcM s (Maybe Type)
451 tcReadMutTyVar tyvar down env = readMutTyVar tyvar
453 tcWriteMutTyVar :: TyVar -> Maybe Type -> NF_TcM s ()
454 tcWriteMutTyVar tyvar val down env = writeMutTyVar tyvar val
461 tcGetEnv :: NF_TcM s TcEnv
462 tcGetEnv down env = return env
464 tcSetEnv :: TcEnv -> Either_TcM s a -> Either_TcM s a
465 tcSetEnv new_env m down old_env = m down new_env
472 tcGetDefaultTys :: NF_TcM s [Type]
473 tcGetDefaultTys down env = return (getDefaultTys down)
475 tcSetDefaultTys :: [Type] -> TcM s r -> TcM s r
476 tcSetDefaultTys tys m down env = m (setDefaultTys down tys) env
478 tcAddSrcLoc :: SrcLoc -> Either_TcM s a -> Either_TcM s a
479 tcAddSrcLoc loc m down env = m (setLoc down loc) env
481 tcGetSrcLoc :: NF_TcM s SrcLoc
482 tcGetSrcLoc down env = return (getLoc down)
484 tcGetInstLoc :: InstOrigin -> NF_TcM s InstLoc
485 tcGetInstLoc origin down env = return (origin, getLoc down, getErrCtxt down)
487 tcSetErrCtxtM, tcAddErrCtxtM :: (TidyEnv -> NF_TcM s (TidyEnv, Message))
488 -> TcM s a -> TcM s a
489 tcSetErrCtxtM msg m down env = m (setErrCtxt down msg) env
490 tcAddErrCtxtM msg m down env = m (addErrCtxt down msg) env
492 tcSetErrCtxt, tcAddErrCtxt :: Message -> Either_TcM s r -> Either_TcM s r
494 tcSetErrCtxt msg m down env = m (setErrCtxt down (\env -> returnNF_Tc (env, msg))) env
495 tcAddErrCtxt msg m down env = m (addErrCtxt down (\env -> returnNF_Tc (env, msg))) env
502 tcGetUnique :: NF_TcM s Unique
504 = do uniq_supply <- readIORef u_var
505 let (new_uniq_supply, uniq_s) = splitUniqSupply uniq_supply
506 uniq = uniqFromSupply uniq_s
507 writeIORef u_var new_uniq_supply
510 u_var = getUniqSupplyVar down
512 tcGetUniques :: Int -> NF_TcM s [Unique]
513 tcGetUniques n down env
514 = do uniq_supply <- readIORef u_var
515 let (new_uniq_supply, uniq_s) = splitUniqSupply uniq_supply
516 uniqs = uniqsFromSupply n uniq_s
517 writeIORef u_var new_uniq_supply
520 u_var = getUniqSupplyVar down
522 uniqSMToTcM :: UniqSM a -> NF_TcM s a
523 uniqSMToTcM m down env
524 = do uniq_supply <- readIORef u_var
525 let (new_uniq_supply, uniq_s) = splitUniqSupply uniq_supply
526 writeIORef u_var new_uniq_supply
527 return (initUs_ uniq_s m)
529 u_var = getUniqSupplyVar down
539 [Type] -- Types used for defaulting
541 (TcRef UniqSupply) -- Unique supply
543 SrcLoc -- Source location
544 ErrCtxt -- Error context
548 type ErrCtxt = [TidyEnv -> NF_TcM Unused (TidyEnv, Message)]
549 -- Innermost first. Monadic so that we have a chance
550 -- to deal with bound type variables just before error
551 -- message construction
554 -- These selectors are *local* to TcMonad.lhs
557 getTcErrs (TcDown def us loc ctxt errs) = errs
558 setTcErrs (TcDown def us loc ctxt _ ) errs = TcDown def us loc ctxt errs
560 getDefaultTys (TcDown def us loc ctxt errs) = def
561 setDefaultTys (TcDown _ us loc ctxt errs) def = TcDown def us loc ctxt errs
563 getLoc (TcDown def us loc ctxt errs) = loc
564 setLoc (TcDown def us _ ctxt errs) loc = TcDown def us loc ctxt errs
566 getUniqSupplyVar (TcDown def us loc ctxt errs) = us
568 setErrCtxt (TcDown def us loc ctxt errs) msg = TcDown def us loc [msg] errs
569 addErrCtxt (TcDown def us loc ctxt errs) msg = TcDown def us loc (msg:ctxt) errs
570 getErrCtxt (TcDown def us loc ctxt errs) = ctxt
580 type TcError = Message
581 type TcWarning = Message
583 ctxt_to_use ctxt | opt_PprStyle_Debug = ctxt
584 | otherwise = takeAtMost 3 ctxt
586 takeAtMost :: Int -> [a] -> [a]
589 takeAtMost n (x:xs) = x:takeAtMost (n-1) xs
591 arityErr kind name n m
592 = hsep [ text kind, quotes (ppr name), ptext SLIT("should have"),
593 n_arguments <> comma, text "but has been given", int m]
595 n_arguments | n == 0 = ptext SLIT("no arguments")
596 | n == 1 = ptext SLIT("1 argument")
597 | True = hsep [int n, ptext SLIT("arguments")]
602 %************************************************************************
604 \subsection[Inst-origin]{The @InstOrigin@ type}
606 %************************************************************************
608 The @InstOrigin@ type gives information about where a dictionary came from.
609 This is important for decent error message reporting because dictionaries
610 don't appear in the original source code. Doubtless this type will evolve...
612 It appears in TcMonad because there are a couple of error-message-generation
613 functions that deal with it.
616 type InstLoc = (InstOrigin, SrcLoc, ErrCtxt)
619 = OccurrenceOf Id -- Occurrence of an overloaded identifier
623 | DataDeclOrigin -- Typechecking a data declaration
625 | InstanceDeclOrigin -- Typechecking an instance decl
627 | LiteralOrigin HsLit -- Occurrence of a literal
629 | PatOrigin RenamedPat
631 | ArithSeqOrigin RenamedArithSeqInfo -- [x..], [x..y] etc
633 | SignatureOrigin -- A dict created from a type signature
634 | Rank2Origin -- A dict created when typechecking the argument
635 -- of a rank-2 typed function
637 | DoOrigin -- The monad for a do expression
639 | ClassDeclOrigin -- Manufactured during a class decl
641 | InstanceSpecOrigin Class -- in a SPECIALIZE instance pragma
644 -- When specialising instances the instance info attached to
645 -- each class is not yet ready, so we record it inside the
646 -- origin information. This is a bit of a hack, but it works
647 -- fine. (Patrick is to blame [WDP].)
649 | ValSpecOrigin Name -- in a SPECIALIZE pragma for a value
651 -- Argument or result of a ccall
652 -- Dictionaries with this origin aren't actually mentioned in the
653 -- translated term, and so need not be bound. Nor should they
654 -- be abstracted over.
656 | CCallOrigin String -- CCall label
657 (Maybe RenamedHsExpr) -- Nothing if it's the result
658 -- Just arg, for an argument
660 | LitLitOrigin String -- the litlit
662 | UnknownOrigin -- Help! I give up...
666 pprInstLoc :: InstLoc -> SDoc
667 pprInstLoc (orig, locn, ctxt)
668 = hsep [text "arising from", pp_orig orig, text "at", ppr locn]
670 pp_orig (OccurrenceOf id)
671 = hsep [ptext SLIT("use of"), quotes (ppr id)]
672 pp_orig (LiteralOrigin lit)
673 = hsep [ptext SLIT("the literal"), quotes (ppr lit)]
674 pp_orig (PatOrigin pat)
675 = hsep [ptext SLIT("the pattern"), quotes (ppr pat)]
676 pp_orig (InstanceDeclOrigin)
677 = ptext SLIT("an instance declaration")
678 pp_orig (ArithSeqOrigin seq)
679 = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)]
680 pp_orig (SignatureOrigin)
681 = ptext SLIT("a type signature")
682 pp_orig (Rank2Origin)
683 = ptext SLIT("a function with an overloaded argument type")
685 = ptext SLIT("a do statement")
686 pp_orig (ClassDeclOrigin)
687 = ptext SLIT("a class declaration")
688 pp_orig (InstanceSpecOrigin clas ty)
689 = hsep [text "a SPECIALIZE instance pragma; class",
690 quotes (ppr clas), text "type:", ppr ty]
691 pp_orig (ValSpecOrigin name)
692 = hsep [ptext SLIT("a SPECIALIZE user-pragma for"), quotes (ppr name)]
693 pp_orig (CCallOrigin clabel Nothing{-ccall result-})
694 = hsep [ptext SLIT("the result of the _ccall_ to"), quotes (text clabel)]
695 pp_orig (CCallOrigin clabel (Just arg_expr))
696 = hsep [ptext SLIT("an argument in the _ccall_ to"), quotes (text clabel) <> comma,
697 text "namely", quotes (ppr arg_expr)]
698 pp_orig (LitLitOrigin s)
699 = hsep [ptext SLIT("the ``literal-literal''"), quotes (text s)]
700 pp_orig (UnknownOrigin)
701 = ptext SLIT("...oops -- I don't know where the overloading came from!")