4 TcTauType, TcPredType, TcThetaType, TcRhoType,
8 TcM, NF_TcM, TcDown, TcEnv,
11 returnTc, thenTc, thenTc_, mapTc, 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, tcGetDFunUniq,
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 RnHsSyn ( RenamedPat, RenamedArithSeqInfo, RenamedHsExpr, RenamedHsOverLit )
49 import Type ( Type, Kind, PredType, ThetaType, RhoType, TauType,
51 import ErrUtils ( addShortErrLocLine, addShortWarnLocLine, ErrMsg, Message, WarnMsg )
52 import CmdLineOpts ( opt_PprStyle_Debug )
54 import Bag ( Bag, emptyBag, isEmptyBag,
55 foldBag, unitBag, unionBags, snocBag )
56 import Class ( Class )
58 import Var ( Id, TyVar, newMutTyVar, newSigTyVar, readMutTyVar, writeMutTyVar )
59 import VarEnv ( TidyEnv, emptyTidyEnv )
60 import VarSet ( TyVarSet )
61 import UniqSupply ( UniqSupply, uniqFromSupply, uniqsFromSupply, splitUniqSupply,
63 import SrcLoc ( SrcLoc, noSrcLoc )
64 import FiniteMap ( FiniteMap, lookupFM, addToFM, emptyFM )
65 import UniqFM ( UniqFM, emptyUFM )
66 import Unique ( Unique )
67 import BasicTypes ( Unused )
69 import FastString ( FastString )
71 import IOExts ( IORef, newIORef, readIORef, writeIORef,
72 unsafeInterleaveIO, fixIO
76 infixr 9 `thenTc`, `thenTc_`, `thenNF_Tc`, `thenNF_Tc_`
80 %************************************************************************
84 %************************************************************************
87 type TcTyVar = TyVar -- Might be a mutable tyvar
88 type TcTyVarSet = TyVarSet
90 type TcType = Type -- A TcType can have mutable type variables
91 -- Invariant on ForAllTy in TcTypes:
93 -- a cannot occur inside a MutTyVar in T; that is,
94 -- T is "flattened" before quantifying over a
96 type TcPredType = PredType
97 type TcThetaType = ThetaType
98 type TcRhoType = RhoType
99 type TcTauType = TauType
104 %************************************************************************
106 \subsection{The main monads: TcM, NF_TcM}
108 %************************************************************************
111 type NF_TcM r = TcDown -> TcEnv -> IO r -- Can't raise UserError
112 type TcM s r = TcDown -> TcEnv -> IO r -- Can raise UserError
113 -- ToDo: nuke the 's' part
114 -- The difference between the two is
115 -- now for documentation purposes only
117 type Either_TcM r = TcDown -> TcEnv -> IO r -- Either NF_TcM or TcM
118 -- Used only in this file for type signatures which
119 -- have a part that's polymorphic in whether it's NF_TcM or TcM
122 type TcRef a = IORef a
126 -- initEnv is passed in to avoid module recursion between TcEnv & TcMonad.
129 -> (TcRef (UniqFM a) -> TcEnv)
131 -> IO (Maybe r, Bag WarnMsg, Bag ErrMsg)
133 initTc us initenv do_this
135 us_var <- newIORef us ;
136 dfun_var <- newIORef emptyFM ;
137 errs_var <- newIORef (emptyBag,emptyBag) ;
138 tvs_var <- newIORef emptyUFM ;
141 init_down = TcDown [] us_var dfun_var
144 init_env = initenv tvs_var
147 maybe_res <- catch (do { res <- do_this init_down init_env ;
149 (\_ -> return Nothing) ;
151 (warns,errs) <- readIORef errs_var ;
152 return (maybe_res, warns, errs)
155 -- Monadic operations
157 returnNF_Tc :: a -> NF_TcM a
158 returnTc :: a -> TcM a
159 returnTc v down env = return v
161 thenTc :: TcM a -> (a -> TcM b) -> TcM b
162 thenNF_Tc :: NF_TcM a -> (a -> Either_TcM b) -> Either_TcM b
163 thenTc m k down env = do { r <- m down env; k r down env }
165 thenTc_ :: TcM a -> TcM b -> TcM b
166 thenNF_Tc_ :: NF_TcM a -> Either_TcM b -> Either_TcM b
167 thenTc_ m k down env = do { m down env; k down env }
169 listTc :: [TcM a] -> TcM [a]
170 listNF_Tc :: [NF_TcM a] -> NF_TcM [a]
171 listTc [] = returnTc []
172 listTc (x:xs) = x `thenTc` \ r ->
173 listTc xs `thenTc` \ rs ->
176 mapTc :: (a -> TcM b) -> [a] -> TcM [b]
177 mapTc_ :: (a -> TcM b) -> [a] -> TcM ()
178 mapNF_Tc :: (a -> NF_TcM b) -> [a] -> NF_TcM [b]
179 mapTc f [] = returnTc []
180 mapTc f (x:xs) = f x `thenTc` \ r ->
181 mapTc f xs `thenTc` \ rs ->
183 mapTc_ f xs = mapTc f xs `thenTc_` returnTc ()
186 foldrTc :: (a -> b -> TcM b) -> b -> [a] -> TcM b
187 foldrNF_Tc :: (a -> b -> NF_TcM b) -> b -> [a] -> NF_TcM b
188 foldrTc k z [] = returnTc z
189 foldrTc k z (x:xs) = foldrTc k z xs `thenTc` \r ->
192 foldlTc :: (a -> b -> TcM a) -> a -> [b] -> TcM a
193 foldlNF_Tc :: (a -> b -> NF_TcM a) -> a -> [b] -> NF_TcM a
194 foldlTc k z [] = returnTc z
195 foldlTc k z (x:xs) = k z x `thenTc` \r ->
198 mapAndUnzipTc :: (a -> TcM (b,c)) -> [a] -> TcM ([b],[c])
199 mapAndUnzipNF_Tc :: (a -> NF_TcM (b,c)) -> [a] -> NF_TcM ([b],[c])
200 mapAndUnzipTc f [] = returnTc ([],[])
201 mapAndUnzipTc f (x:xs) = f x `thenTc` \ (r1,r2) ->
202 mapAndUnzipTc f xs `thenTc` \ (rs1,rs2) ->
203 returnTc (r1:rs1, r2:rs2)
205 mapAndUnzip3Tc :: (a -> TcM (b,c,d)) -> [a] -> TcM ([b],[c],[d])
206 mapAndUnzip3Tc f [] = returnTc ([],[],[])
207 mapAndUnzip3Tc f (x:xs) = f x `thenTc` \ (r1,r2,r3) ->
208 mapAndUnzip3Tc f xs `thenTc` \ (rs1,rs2,rs3) ->
209 returnTc (r1:rs1, r2:rs2, r3:rs3)
211 mapBagTc :: (a -> TcM b) -> Bag a -> TcM (Bag b)
212 mapBagNF_Tc :: (a -> NF_TcM b) -> Bag a -> NF_TcM (Bag b)
214 = foldBag (\ b1 b2 -> b1 `thenTc` \ r1 ->
216 returnTc (unionBags r1 r2))
217 (\ a -> f a `thenTc` \ r -> returnTc (unitBag r))
221 fixTc :: (a -> TcM a) -> TcM a
222 fixNF_Tc :: (a -> NF_TcM a) -> NF_TcM a
223 fixTc m env down = fixIO (\ loop -> m loop env down)
225 recoverTc :: TcM r -> TcM r -> TcM r
226 recoverNF_Tc :: NF_TcM r -> TcM r -> NF_TcM r
227 recoverTc recover m down env
228 = catch (m down env) (\ _ -> recover down env)
230 returnNF_Tc = returnTc
234 recoverNF_Tc = recoverTc
239 mapAndUnzipNF_Tc = mapAndUnzipTc
240 mapBagNF_Tc = mapBagTc
243 @forkNF_Tc@ runs a sub-typecheck action *lazily* in a separate state
244 thread. Ideally, this elegantly ensures that it can't zap any type
245 variables that belong to the main thread. But alas, the environment
246 contains TyCon and Class environments that include TcKind stuff,
247 which is a Royal Pain. By the time this fork stuff is used they'll
248 have been unified down so there won't be any kind variables, but we
249 can't express that in the current typechecker framework.
251 So we compromise and use unsafeInterleaveSST.
253 We throw away any error messages!
256 forkNF_Tc :: NF_TcM r -> NF_TcM r
257 forkNF_Tc m (TcDown deflts u_var df_var src_loc err_cxt err_var) env
259 -- Get a fresh unique supply
260 us <- readIORef u_var
261 let (us1, us2) = splitUniqSupply us
264 unsafeInterleaveIO (do {
265 us_var' <- newIORef us2 ;
266 err_var' <- newIORef (emptyBag,emptyBag) ;
267 tv_var' <- newIORef emptyUFM ;
268 let { down' = TcDown deflts us_var' df_var src_loc err_cxt err_var' } ;
270 -- ToDo: optionally dump any error messages
275 traceTc :: SDoc -> NF_TcM ()
276 traceTc doc down env = printErrs doc
278 ioToTc :: IO a -> NF_TcM a
279 ioToTc io down env = io
283 %************************************************************************
285 \subsection{Error handling}
287 %************************************************************************
290 getErrsTc :: NF_TcM (Bag WarnMsg, Bag ErrMsg)
292 = readIORef (getTcErrs down)
295 failTc down env = give_up
298 give_up = IOERROR (userError "Typecheck failed")
300 failWithTc :: Message -> TcM a -- Add an error message and fail
301 failWithTc err_msg = failWithTcM (emptyTidyEnv, err_msg)
303 addErrTc :: Message -> NF_TcM ()
304 addErrTc err_msg = addErrTcM (emptyTidyEnv, err_msg)
306 -- The 'M' variants do the TidyEnv bit
307 failWithTcM :: (TidyEnv, Message) -> TcM a -- Add an error message and fail
308 failWithTcM env_and_msg
309 = addErrTcM env_and_msg `thenNF_Tc_`
312 checkTc :: Bool -> Message -> TcM () -- Check that the boolean is true
313 checkTc True err = returnTc ()
314 checkTc False err = failWithTc err
316 checkTcM :: Bool -> TcM () -> TcM () -- Check that the boolean is true
317 checkTcM True err = returnTc ()
318 checkTcM False err = err
320 checkMaybeTc :: Maybe val -> Message -> TcM val
321 checkMaybeTc (Just val) err = returnTc val
322 checkMaybeTc Nothing err = failWithTc err
324 checkMaybeTcM :: Maybe val -> TcM val -> TcM val
325 checkMaybeTcM (Just val) err = returnTc val
326 checkMaybeTcM Nothing err = err
328 addErrTcM :: (TidyEnv, Message) -> NF_TcM () -- Add an error message but don't fail
329 addErrTcM (tidy_env, err_msg) down env
330 = add_err_tcm tidy_env err_msg ctxt loc down env
332 ctxt = getErrCtxt down
335 addInstErrTcM :: InstLoc -> (TidyEnv, Message) -> NF_TcM () -- Add an error message but don't fail
336 addInstErrTcM inst_loc@(_, loc, ctxt) (tidy_env, err_msg) down env
337 = add_err_tcm tidy_env err_msg full_ctxt loc down env
339 full_ctxt = (\env -> returnNF_Tc (env, pprInstLoc inst_loc)) : ctxt
341 add_err_tcm tidy_env err_msg ctxt loc down env
343 (warns, errs) <- readIORef errs_var
344 ctxt_msgs <- do_ctxt tidy_env ctxt down env
345 let err = addShortErrLocLine loc $
346 vcat (err_msg : ctxt_to_use ctxt_msgs)
347 writeIORef errs_var (warns, errs `snocBag` err)
349 errs_var = getTcErrs down
351 do_ctxt tidy_env [] down env
353 do_ctxt tidy_env (c:cs) down env
355 (tidy_env', m) <- c tidy_env down env
356 ms <- do_ctxt tidy_env' cs down env
359 -- warnings don't have an 'M' variant
360 warnTc :: Bool -> Message -> NF_TcM ()
361 warnTc warn_if_true warn_msg down env
364 (warns,errs) <- readIORef errs_var
365 ctxt_msgs <- do_ctxt emptyTidyEnv ctxt down env
366 let warn = addShortWarnLocLine loc $
367 vcat (warn_msg : ctxt_to_use ctxt_msgs)
368 writeIORef errs_var (warns `snocBag` warn, errs)
372 errs_var = getTcErrs down
373 ctxt = getErrCtxt down
376 -- (tryTc r m) succeeds if m succeeds and generates no errors
377 -- If m fails then r is invoked, passing the warnings and errors from m
378 -- If m succeeds, (tryTc r m) checks whether m generated any errors messages
379 -- (it might have recovered internally)
380 -- If so, then r is invoked, passing the warnings and errors from m
382 tryTc :: ((Bag WarnMsg, Bag ErrMsg) -> TcM r) -- Recovery action
383 -> TcM r -- Thing to try
385 tryTc recover main down env
387 m_errs_var <- newIORef (emptyBag,emptyBag)
388 catch (my_main m_errs_var) (\ _ -> my_recover m_errs_var)
390 my_recover m_errs_var
391 = do warns_and_errs <- readIORef m_errs_var
392 recover warns_and_errs down env
395 = do result <- main (setTcErrs down m_errs_var) env
397 -- Check that m has no errors; if it has internal recovery
398 -- mechanisms it might "succeed" but having found a bunch of
399 -- errors along the way.
400 (m_warns, m_errs) <- readIORef m_errs_var
401 if isEmptyBag m_errs then
404 give_up -- This triggers the catch
407 -- (checkNoErrsTc m) succeeds iff m succeeds and generates no errors
408 -- If m fails then (checkNoErrsTc m) fails.
409 -- If m succeeds, it checks whether m generated any errors messages
410 -- (it might have recovered internally)
411 -- If so, it fails too.
412 -- Regardless, any errors generated by m are propagated to the enclosing context.
413 checkNoErrsTc :: TcM r -> TcM r
415 = tryTc my_recover main
417 my_recover (m_warns, m_errs) down env
418 = do (warns, errs) <- readIORef errs_var
419 writeIORef errs_var (warns `unionBags` m_warns,
420 errs `unionBags` m_errs)
423 errs_var = getTcErrs down
426 -- (tryTc_ r m) tries m; if it succeeds it returns it,
427 -- otherwise it returns r. Any error messages added by m are discarded,
428 -- whether or not m succeeds.
429 tryTc_ :: TcM r -> TcM r -> TcM r
431 = tryTc my_recover main
433 my_recover warns_and_errs = recover
435 -- (discardErrsTc m) runs m, but throw away all its error messages.
436 discardErrsTc :: Either_TcM r -> Either_TcM r
437 discardErrsTc main down env
438 = do new_errs_var <- newIORef (emptyBag,emptyBag)
439 main (setTcErrs down new_errs_var) env
444 %************************************************************************
446 \subsection{Mutable variables}
448 %************************************************************************
451 tcNewMutVar :: a -> NF_TcM (TcRef a)
452 tcNewMutVar val down env = newIORef val
454 tcWriteMutVar :: TcRef a -> a -> NF_TcM ()
455 tcWriteMutVar var val down env = writeIORef var val
457 tcReadMutVar :: TcRef a -> NF_TcM a
458 tcReadMutVar var down env = readIORef var
460 tcNewMutTyVar :: Name -> Kind -> NF_TcM TyVar
461 tcNewMutTyVar name kind down env = newMutTyVar name kind
463 tcNewSigTyVar :: Name -> Kind -> NF_TcM TyVar
464 tcNewSigTyVar name kind down env = newSigTyVar name kind
466 tcReadMutTyVar :: TyVar -> NF_TcM (Maybe Type)
467 tcReadMutTyVar tyvar down env = readMutTyVar tyvar
469 tcWriteMutTyVar :: TyVar -> Maybe Type -> NF_TcM ()
470 tcWriteMutTyVar tyvar val down env = writeMutTyVar tyvar val
474 %************************************************************************
476 \subsection{The environment}
478 %************************************************************************
481 tcGetEnv :: NF_TcM TcEnv
482 tcGetEnv down env = return env
484 tcSetEnv :: TcEnv -> Either_TcM a -> Either_TcM a
485 tcSetEnv new_env m down old_env = m down new_env
489 %************************************************************************
491 \subsection{Source location}
493 %************************************************************************
496 tcGetDefaultTys :: NF_TcM [Type]
497 tcGetDefaultTys down env = return (getDefaultTys down)
499 tcSetDefaultTys :: [Type] -> TcM r -> TcM r
500 tcSetDefaultTys tys m down env = m (setDefaultTys down tys) env
502 tcAddSrcLoc :: SrcLoc -> Either_TcM a -> Either_TcM a
503 tcAddSrcLoc loc m down env = m (setLoc down loc) env
505 tcGetSrcLoc :: NF_TcM SrcLoc
506 tcGetSrcLoc down env = return (getLoc down)
508 tcGetInstLoc :: InstOrigin -> NF_TcM InstLoc
509 tcGetInstLoc origin down env = return (origin, getLoc down, getErrCtxt down)
511 tcSetErrCtxtM, tcAddErrCtxtM :: (TidyEnv -> NF_TcM (TidyEnv, Message))
513 tcSetErrCtxtM msg m down env = m (setErrCtxt down msg) env
514 tcAddErrCtxtM msg m down env = m (addErrCtxt down msg) env
516 tcSetErrCtxt, tcAddErrCtxt :: Message -> Either_TcM r -> Either_TcM r
518 tcSetErrCtxt msg m down env = m (setErrCtxt down (\env -> returnNF_Tc (env, msg))) env
519 tcAddErrCtxt msg m down env = m (addErrCtxt down (\env -> returnNF_Tc (env, msg))) env
523 %************************************************************************
525 \subsection{Unique supply}
527 %************************************************************************
530 tcGetUnique :: NF_TcM Unique
532 = do uniq_supply <- readIORef u_var
533 let (new_uniq_supply, uniq_s) = splitUniqSupply uniq_supply
534 uniq = uniqFromSupply uniq_s
535 writeIORef u_var new_uniq_supply
538 u_var = getUniqSupplyVar down
540 tcGetUniques :: Int -> NF_TcM [Unique]
541 tcGetUniques n down env
542 = do uniq_supply <- readIORef u_var
543 let (new_uniq_supply, uniq_s) = splitUniqSupply uniq_supply
544 uniqs = uniqsFromSupply n uniq_s
545 writeIORef u_var new_uniq_supply
548 u_var = getUniqSupplyVar down
550 uniqSMToTcM :: UniqSM a -> NF_TcM a
551 uniqSMToTcM m down env
552 = do uniq_supply <- readIORef u_var
553 let (new_uniq_supply, uniq_s) = splitUniqSupply uniq_supply
554 writeIORef u_var new_uniq_supply
555 return (initUs_ uniq_s m)
557 u_var = getUniqSupplyVar down
562 tcGetDFunUniq :: String -> NF_TcM Int
563 tcGetDFunUniq key down env
564 = do dfun_supply <- readIORef d_var
565 let uniq = case lookupFM dfun_supply key of
568 let dfun_supply' = addToFM dfun_supply key uniq
569 writeIORef d_var dfun_supply'
572 d_var = getDFunSupplyVar down
576 %************************************************************************
580 %************************************************************************
585 [Type] -- Types used for defaulting
587 (TcRef UniqSupply) -- Unique supply
588 (TcRef DFunNameSupply) -- Name supply for dictionary function names
590 SrcLoc -- Source location
591 ErrCtxt -- Error context
592 (TcRef (Bag WarnMsg, Bag ErrMsg))
594 type ErrCtxt = [TidyEnv -> NF_TcM Unused (TidyEnv, Message)]
595 -- Innermost first. Monadic so that we have a chance
596 -- to deal with bound type variables just before error
597 -- message construction
599 type DFunNameSupply = FiniteMap String Int
600 -- This is used as a name supply for dictionary functions
601 -- From the inst decl we derive a string, usually by glomming together
602 -- the class and tycon name -- but it doesn't matter exactly how;
603 -- this map then gives a unique int for each inst decl with that
604 -- string. (In Haskell 98 there can only be one,
605 -- but not so in more extended versions; also class CC type T
606 -- and class C type TT might both give the string CCT
608 -- We could just use one Int for all the instance decls, but this
609 -- way the uniques change less when you add an instance decl,
610 -- hence less recompilation
613 -- These selectors are *local* to TcMonad.lhs
616 getTcErrs (TcDown def us ds loc ctxt errs) = errs
617 setTcErrs (TcDown def us ds loc ctxt _ ) errs = TcDown def us ds loc ctxt errs
619 getDefaultTys (TcDown def us ds loc ctxt errs) = def
620 setDefaultTys (TcDown _ us ds loc ctxt errs) def = TcDown def us ds loc ctxt errs
622 getLoc (TcDown def us ds loc ctxt errs) = loc
623 setLoc (TcDown def us ds _ ctxt errs) loc = TcDown def us ds loc ctxt errs
625 getUniqSupplyVar (TcDown def us ds loc ctxt errs) = us
626 getDFunSupplyVar (TcDown def us ds loc ctxt errs) = ds
628 setErrCtxt (TcDown def us ds loc ctxt errs) msg = TcDown def us ds loc [msg] errs
629 addErrCtxt (TcDown def us ds loc ctxt errs) msg = TcDown def us ds loc (msg:ctxt) errs
630 getErrCtxt (TcDown def us ds loc ctxt errs) = ctxt
636 %************************************************************************
638 \subsection{TypeChecking Errors}
640 %************************************************************************
643 type TcError = Message
644 type TcWarning = Message
646 ctxt_to_use ctxt | opt_PprStyle_Debug = ctxt
647 | otherwise = takeAtMost 3 ctxt
649 takeAtMost :: Int -> [a] -> [a]
652 takeAtMost n (x:xs) = x:takeAtMost (n-1) xs
654 arityErr kind name n m
655 = hsep [ text kind, quotes (ppr name), ptext SLIT("should have"),
656 n_arguments <> comma, text "but has been given", int m]
658 n_arguments | n == 0 = ptext SLIT("no arguments")
659 | n == 1 = ptext SLIT("1 argument")
660 | True = hsep [int n, ptext SLIT("arguments")]
665 %************************************************************************
667 \subsection[Inst-origin]{The @InstOrigin@ type}
669 %************************************************************************
671 The @InstOrigin@ type gives information about where a dictionary came from.
672 This is important for decent error message reporting because dictionaries
673 don't appear in the original source code. Doubtless this type will evolve...
675 It appears in TcMonad because there are a couple of error-message-generation
676 functions that deal with it.
679 type InstLoc = (InstOrigin, SrcLoc, ErrCtxt)
682 = OccurrenceOf Id -- Occurrence of an overloaded identifier
686 | DataDeclOrigin -- Typechecking a data declaration
688 | InstanceDeclOrigin -- Typechecking an instance decl
690 | LiteralOrigin RenamedHsOverLit -- Occurrence of a literal
692 | PatOrigin RenamedPat
694 | ArithSeqOrigin RenamedArithSeqInfo -- [x..], [x..y] etc
696 | SignatureOrigin -- A dict created from a type signature
697 | Rank2Origin -- A dict created when typechecking the argument
698 -- of a rank-2 typed function
700 | DoOrigin -- The monad for a do expression
702 | ClassDeclOrigin -- Manufactured during a class decl
704 | InstanceSpecOrigin Class -- in a SPECIALIZE instance pragma
707 -- When specialising instances the instance info attached to
708 -- each class is not yet ready, so we record it inside the
709 -- origin information. This is a bit of a hack, but it works
710 -- fine. (Patrick is to blame [WDP].)
712 | ValSpecOrigin Name -- in a SPECIALIZE pragma for a value
714 -- Argument or result of a ccall
715 -- Dictionaries with this origin aren't actually mentioned in the
716 -- translated term, and so need not be bound. Nor should they
717 -- be abstracted over.
719 | CCallOrigin String -- CCall label
720 (Maybe RenamedHsExpr) -- Nothing if it's the result
721 -- Just arg, for an argument
723 | LitLitOrigin String -- the litlit
725 | UnknownOrigin -- Help! I give up...
729 pprInstLoc :: InstLoc -> SDoc
730 pprInstLoc (orig, locn, ctxt)
731 = hsep [text "arising from", pp_orig orig, text "at", ppr locn]
733 pp_orig (OccurrenceOf id)
734 = hsep [ptext SLIT("use of"), quotes (ppr id)]
735 pp_orig (LiteralOrigin lit)
736 = hsep [ptext SLIT("the literal"), quotes (ppr lit)]
737 pp_orig (PatOrigin pat)
738 = hsep [ptext SLIT("the pattern"), quotes (ppr pat)]
739 pp_orig (InstanceDeclOrigin)
740 = ptext SLIT("an instance declaration")
741 pp_orig (ArithSeqOrigin seq)
742 = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)]
743 pp_orig (SignatureOrigin)
744 = ptext SLIT("a type signature")
745 pp_orig (Rank2Origin)
746 = ptext SLIT("a function with an overloaded argument type")
748 = ptext SLIT("a do statement")
749 pp_orig (ClassDeclOrigin)
750 = ptext SLIT("a class declaration")
751 pp_orig (InstanceSpecOrigin clas ty)
752 = hsep [text "a SPECIALIZE instance pragma; class",
753 quotes (ppr clas), text "type:", ppr ty]
754 pp_orig (ValSpecOrigin name)
755 = hsep [ptext SLIT("a SPECIALIZE user-pragma for"), quotes (ppr name)]
756 pp_orig (CCallOrigin clabel Nothing{-ccall result-})
757 = hsep [ptext SLIT("the result of the _ccall_ to"), quotes (text clabel)]
758 pp_orig (CCallOrigin clabel (Just arg_expr))
759 = hsep [ptext SLIT("an argument in the _ccall_ to"), quotes (text clabel) <> comma,
760 text "namely", quotes (ppr arg_expr)]
761 pp_orig (LitLitOrigin s)
762 = hsep [ptext SLIT("the ``literal-literal''"), quotes (text s)]
763 pp_orig (UnknownOrigin)
764 = ptext SLIT("...oops -- I don't know where the overloading came from!")