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, addErrsTc, warnTc,
25 recoverTc, checkNoErrsTc, recoverNF_Tc, discardErrsTc,
26 addErrTcM, addInstErrTcM, failWithTcM,
29 tcGetDefaultTys, tcSetDefaultTys,
30 tcGetUnique, tcGetUniques, tcGetDFunUniq,
33 tcAddSrcLoc, tcGetSrcLoc, tcGetInstLoc,
34 tcAddErrCtxtM, tcSetErrCtxtM,
35 tcAddErrCtxt, tcSetErrCtxt,
37 tcNewMutVar, tcNewSigTyVar, tcReadMutVar, tcWriteMutVar, TcRef,
38 tcNewMutTyVar, tcReadMutTyVar, tcWriteMutTyVar,
40 InstOrigin(..), InstLoc, pprInstLoc,
42 TcError, TcWarning, TidyEnv, emptyTidyEnv,
46 #include "HsVersions.h"
48 import {-# SOURCE #-} TcEnv ( TcEnv )
50 import RnHsSyn ( RenamedPat, RenamedArithSeqInfo, RenamedHsExpr, RenamedHsOverLit )
51 import Type ( Type, Kind, PredType, ThetaType, RhoType, TauType,
53 import ErrUtils ( addShortErrLocLine, addShortWarnLocLine, ErrMsg, Message, WarnMsg )
54 import CmdLineOpts ( DynFlags, opt_PprStyle_Debug )
56 import Bag ( Bag, emptyBag, isEmptyBag,
57 foldBag, unitBag, unionBags, snocBag )
58 import Class ( Class )
60 import Var ( Id, TyVar, newMutTyVar, newSigTyVar, readMutTyVar, writeMutTyVar )
61 import VarEnv ( TidyEnv, emptyTidyEnv )
62 import VarSet ( TyVarSet )
63 import UniqSupply ( UniqSupply, uniqFromSupply, uniqsFromSupply,
64 splitUniqSupply, mkSplitUniqSupply,
66 import SrcLoc ( SrcLoc, noSrcLoc )
67 import FiniteMap ( FiniteMap, lookupFM, addToFM, emptyFM )
68 import UniqFM ( UniqFM, emptyUFM )
69 import Unique ( Unique )
70 import BasicTypes ( Unused )
72 import FastString ( FastString )
74 import IOExts ( IORef, newIORef, readIORef, writeIORef,
75 unsafeInterleaveIO, fixIO
79 infixr 9 `thenTc`, `thenTc_`, `thenNF_Tc`, `thenNF_Tc_`
83 %************************************************************************
87 %************************************************************************
90 type TcTyVar = TyVar -- Might be a mutable tyvar
91 type TcTyVarSet = TyVarSet
93 type TcType = Type -- A TcType can have mutable type variables
94 -- Invariant on ForAllTy in TcTypes:
96 -- a cannot occur inside a MutTyVar in T; that is,
97 -- T is "flattened" before quantifying over a
99 type TcPredType = PredType
100 type TcThetaType = ThetaType
101 type TcRhoType = RhoType
102 type TcTauType = TauType
107 %************************************************************************
109 \subsection{The main monads: TcM, NF_TcM}
111 %************************************************************************
114 type NF_TcM r = TcDown -> TcEnv -> IO r -- Can't raise UserError
115 type TcM r = TcDown -> TcEnv -> IO r -- Can raise UserError
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
131 -> IO (Maybe r, (Bag ErrMsg, Bag WarnMsg))
133 initTc dflags tc_env src_loc do_this
135 us <- mkSplitUniqSupply 'a' ;
136 us_var <- newIORef us ;
137 dfun_var <- newIORef emptyFM ;
138 errs_var <- newIORef (emptyBag,emptyBag) ;
139 tvs_var <- newIORef emptyUFM ;
142 init_down = TcDown dflags [] us_var dfun_var
147 maybe_res <- catch (do { res <- do_this init_down tc_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 dflags 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 dflags 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 addErrsTc :: [Message] -> NF_TcM ()
307 addErrsTc [] = returnNF_Tc ()
308 addErrsTc err_msgs = listNF_Tc (map addErrTc err_msgs) `thenNF_Tc_` returnNF_Tc ()
310 -- The 'M' variants do the TidyEnv bit
311 failWithTcM :: (TidyEnv, Message) -> TcM a -- Add an error message and fail
312 failWithTcM env_and_msg
313 = addErrTcM env_and_msg `thenNF_Tc_`
316 checkTc :: Bool -> Message -> TcM () -- Check that the boolean is true
317 checkTc True err = returnTc ()
318 checkTc False err = failWithTc err
320 checkTcM :: Bool -> TcM () -> TcM () -- Check that the boolean is true
321 checkTcM True err = returnTc ()
322 checkTcM False err = err
324 checkMaybeTc :: Maybe val -> Message -> TcM val
325 checkMaybeTc (Just val) err = returnTc val
326 checkMaybeTc Nothing err = failWithTc err
328 checkMaybeTcM :: Maybe val -> TcM val -> TcM val
329 checkMaybeTcM (Just val) err = returnTc val
330 checkMaybeTcM Nothing err = err
332 addErrTcM :: (TidyEnv, Message) -> NF_TcM () -- Add an error message but don't fail
333 addErrTcM (tidy_env, err_msg) down env
334 = add_err_tcm tidy_env err_msg ctxt loc down env
336 ctxt = getErrCtxt down
339 addInstErrTcM :: InstLoc -> (TidyEnv, Message) -> NF_TcM () -- Add an error message but don't fail
340 addInstErrTcM inst_loc@(_, loc, ctxt) (tidy_env, err_msg) down env
341 = add_err_tcm tidy_env err_msg full_ctxt loc down env
343 full_ctxt = (\env -> returnNF_Tc (env, pprInstLoc inst_loc)) : ctxt
345 add_err_tcm tidy_env err_msg ctxt loc down env
347 (warns, errs) <- readIORef errs_var
348 ctxt_msgs <- do_ctxt tidy_env ctxt down env
349 let err = addShortErrLocLine loc $
350 vcat (err_msg : ctxt_to_use ctxt_msgs)
351 writeIORef errs_var (warns, errs `snocBag` err)
353 errs_var = getTcErrs down
355 do_ctxt tidy_env [] down env
357 do_ctxt tidy_env (c:cs) down env
359 (tidy_env', m) <- c tidy_env down env
360 ms <- do_ctxt tidy_env' cs down env
363 -- warnings don't have an 'M' variant
364 warnTc :: Bool -> Message -> NF_TcM ()
365 warnTc warn_if_true warn_msg down env
368 (warns,errs) <- readIORef errs_var
369 ctxt_msgs <- do_ctxt emptyTidyEnv ctxt down env
370 let warn = addShortWarnLocLine loc $
371 vcat (warn_msg : ctxt_to_use ctxt_msgs)
372 writeIORef errs_var (warns `snocBag` warn, errs)
376 errs_var = getTcErrs down
377 ctxt = getErrCtxt down
380 -- (tryTc r m) succeeds if m succeeds and generates no errors
381 -- If m fails then r is invoked, passing the warnings and errors from m
382 -- If m succeeds, (tryTc r m) checks whether m generated any errors messages
383 -- (it might have recovered internally)
384 -- If so, then r is invoked, passing the warnings and errors from m
386 tryTc :: ((Bag WarnMsg, Bag ErrMsg) -> TcM r) -- Recovery action
387 -> TcM r -- Thing to try
389 tryTc recover main down env
391 m_errs_var <- newIORef (emptyBag,emptyBag)
392 catch (my_main m_errs_var) (\ _ -> my_recover m_errs_var)
394 my_recover m_errs_var
395 = do warns_and_errs <- readIORef m_errs_var
396 recover warns_and_errs down env
399 = do result <- main (setTcErrs down m_errs_var) env
401 -- Check that m has no errors; if it has internal recovery
402 -- mechanisms it might "succeed" but having found a bunch of
403 -- errors along the way.
404 (m_warns, m_errs) <- readIORef m_errs_var
405 if isEmptyBag m_errs then
408 give_up -- This triggers the catch
411 -- (checkNoErrsTc m) succeeds iff m succeeds and generates no errors
412 -- If m fails then (checkNoErrsTc m) fails.
413 -- If m succeeds, it checks whether m generated any errors messages
414 -- (it might have recovered internally)
415 -- If so, it fails too.
416 -- Regardless, any errors generated by m are propagated to the enclosing context.
417 checkNoErrsTc :: TcM r -> TcM r
419 = tryTc my_recover main
421 my_recover (m_warns, m_errs) down env
422 = do (warns, errs) <- readIORef errs_var
423 writeIORef errs_var (warns `unionBags` m_warns,
424 errs `unionBags` m_errs)
427 errs_var = getTcErrs down
430 -- (tryTc_ r m) tries m; if it succeeds it returns it,
431 -- otherwise it returns r. Any error messages added by m are discarded,
432 -- whether or not m succeeds.
433 tryTc_ :: TcM r -> TcM r -> TcM r
435 = tryTc my_recover main
437 my_recover warns_and_errs = recover
439 -- (discardErrsTc m) runs m, but throw away all its error messages.
440 discardErrsTc :: Either_TcM r -> Either_TcM r
441 discardErrsTc main down env
442 = do new_errs_var <- newIORef (emptyBag,emptyBag)
443 main (setTcErrs down new_errs_var) env
448 %************************************************************************
450 \subsection{Mutable variables}
452 %************************************************************************
455 tcNewMutVar :: a -> NF_TcM (TcRef a)
456 tcNewMutVar val down env = newIORef val
458 tcWriteMutVar :: TcRef a -> a -> NF_TcM ()
459 tcWriteMutVar var val down env = writeIORef var val
461 tcReadMutVar :: TcRef a -> NF_TcM a
462 tcReadMutVar var down env = readIORef var
464 tcNewMutTyVar :: Name -> Kind -> NF_TcM TyVar
465 tcNewMutTyVar name kind down env = newMutTyVar name kind
467 tcNewSigTyVar :: Name -> Kind -> NF_TcM TyVar
468 tcNewSigTyVar name kind down env = newSigTyVar name kind
470 tcReadMutTyVar :: TyVar -> NF_TcM (Maybe Type)
471 tcReadMutTyVar tyvar down env = readMutTyVar tyvar
473 tcWriteMutTyVar :: TyVar -> Maybe Type -> NF_TcM ()
474 tcWriteMutTyVar tyvar val down env = writeMutTyVar tyvar val
478 %************************************************************************
480 \subsection{The environment}
482 %************************************************************************
485 tcGetEnv :: NF_TcM TcEnv
486 tcGetEnv down env = return env
488 tcSetEnv :: TcEnv -> Either_TcM a -> Either_TcM a
489 tcSetEnv new_env m down old_env = m down new_env
493 %************************************************************************
495 \subsection{Source location}
497 %************************************************************************
500 tcGetDefaultTys :: NF_TcM [Type]
501 tcGetDefaultTys down env = return (getDefaultTys down)
503 tcSetDefaultTys :: [Type] -> TcM r -> TcM r
504 tcSetDefaultTys tys m down env = m (setDefaultTys down tys) env
506 tcAddSrcLoc :: SrcLoc -> Either_TcM a -> Either_TcM a
507 tcAddSrcLoc loc m down env = m (setLoc down loc) env
509 tcGetSrcLoc :: NF_TcM SrcLoc
510 tcGetSrcLoc down env = return (getLoc down)
512 tcGetInstLoc :: InstOrigin -> NF_TcM InstLoc
513 tcGetInstLoc origin down env = return (origin, getLoc down, getErrCtxt down)
515 tcSetErrCtxtM, tcAddErrCtxtM :: (TidyEnv -> NF_TcM (TidyEnv, Message))
517 tcSetErrCtxtM msg m down env = m (setErrCtxt down msg) env
518 tcAddErrCtxtM msg m down env = m (addErrCtxt down msg) env
520 tcSetErrCtxt, tcAddErrCtxt :: Message -> Either_TcM r -> Either_TcM r
522 tcSetErrCtxt msg m down env = m (setErrCtxt down (\env -> returnNF_Tc (env, msg))) env
523 tcAddErrCtxt msg m down env = m (addErrCtxt down (\env -> returnNF_Tc (env, msg))) env
527 %************************************************************************
529 \subsection{Unique supply}
531 %************************************************************************
534 tcGetUnique :: NF_TcM Unique
536 = do uniq_supply <- readIORef u_var
537 let (new_uniq_supply, uniq_s) = splitUniqSupply uniq_supply
538 uniq = uniqFromSupply uniq_s
539 writeIORef u_var new_uniq_supply
542 u_var = getUniqSupplyVar down
544 tcGetUniques :: Int -> NF_TcM [Unique]
545 tcGetUniques n down env
546 = do uniq_supply <- readIORef u_var
547 let (new_uniq_supply, uniq_s) = splitUniqSupply uniq_supply
548 uniqs = uniqsFromSupply n uniq_s
549 writeIORef u_var new_uniq_supply
552 u_var = getUniqSupplyVar down
554 uniqSMToTcM :: UniqSM a -> NF_TcM a
555 uniqSMToTcM m down env
556 = do uniq_supply <- readIORef u_var
557 let (new_uniq_supply, uniq_s) = splitUniqSupply uniq_supply
558 writeIORef u_var new_uniq_supply
559 return (initUs_ uniq_s m)
561 u_var = getUniqSupplyVar down
566 tcGetDFunUniq :: String -> NF_TcM Int
567 tcGetDFunUniq key down env
568 = do dfun_supply <- readIORef d_var
569 let uniq = case lookupFM dfun_supply key of
572 let dfun_supply' = addToFM dfun_supply key uniq
573 writeIORef d_var dfun_supply'
576 d_var = getDFunSupplyVar down
580 %************************************************************************
584 %************************************************************************
589 tc_dflags :: DynFlags,
590 tc_def :: [Type], -- Types used for defaulting
592 tc_us :: (TcRef UniqSupply), -- Unique supply
593 tc_ds :: (TcRef DFunNameSupply), -- Name supply for
594 -- dictionary function names
596 tc_loc :: SrcLoc, -- Source location
597 tc_ctxt :: ErrCtxt, -- Error context
598 tc_errs :: (TcRef (Bag WarnMsg, Bag ErrMsg))
601 type ErrCtxt = [TidyEnv -> NF_TcM (TidyEnv, Message)]
602 -- Innermost first. Monadic so that we have a chance
603 -- to deal with bound type variables just before error
604 -- message construction
606 type DFunNameSupply = FiniteMap String Int
607 -- This is used as a name supply for dictionary functions
608 -- From the inst decl we derive a string, usually by glomming together
609 -- the class and tycon name -- but it doesn't matter exactly how;
610 -- this map then gives a unique int for each inst decl with that
611 -- string. (In Haskell 98 there can only be one,
612 -- but not so in more extended versions; also class CC type T
613 -- and class C type TT might both give the string CCT
615 -- We could just use one Int for all the instance decls, but this
616 -- way the uniques change less when you add an instance decl,
617 -- hence less recompilation
620 -- These selectors are *local* to TcMonad.lhs
623 getTcErrs (TcDown{tc_errs=errs}) = errs
624 setTcErrs down errs = down{tc_errs=errs}
626 getDefaultTys (TcDown{tc_def=def}) = def
627 setDefaultTys down def = down{tc_def=def}
629 getLoc (TcDown{tc_loc=loc}) = loc
630 setLoc down loc = down{tc_loc=loc}
632 getUniqSupplyVar (TcDown{tc_us=us}) = us
633 getDFunSupplyVar (TcDown{tc_ds=ds}) = ds
635 getErrCtxt (TcDown{tc_ctxt=ctxt}) = ctxt
636 setErrCtxt down msg = down{tc_ctxt=[msg]}
637 addErrCtxt down msg = down{tc_ctxt = msg : tc_ctxt down}
639 doptsTc :: (DynFlags -> Bool) -> TcM Bool
640 doptsTc dopt (TcDown{tc_dflags=dflags}) env_down
641 = return (dopt dflags)
643 getDOptsTc :: TcM DynFlags
644 getDOptsTc (TcDown{tc_dflags=dflags}) env_down
651 %************************************************************************
653 \subsection{TypeChecking Errors}
655 %************************************************************************
658 type TcError = Message
659 type TcWarning = Message
661 ctxt_to_use ctxt | opt_PprStyle_Debug = ctxt
662 | otherwise = takeAtMost 3 ctxt
664 takeAtMost :: Int -> [a] -> [a]
667 takeAtMost n (x:xs) = x:takeAtMost (n-1) xs
669 arityErr kind name n m
670 = hsep [ text kind, quotes (ppr name), ptext SLIT("should have"),
671 n_arguments <> comma, text "but has been given", int m]
673 n_arguments | n == 0 = ptext SLIT("no arguments")
674 | n == 1 = ptext SLIT("1 argument")
675 | True = hsep [int n, ptext SLIT("arguments")]
680 %************************************************************************
682 \subsection[Inst-origin]{The @InstOrigin@ type}
684 %************************************************************************
686 The @InstOrigin@ type gives information about where a dictionary came from.
687 This is important for decent error message reporting because dictionaries
688 don't appear in the original source code. Doubtless this type will evolve...
690 It appears in TcMonad because there are a couple of error-message-generation
691 functions that deal with it.
694 type InstLoc = (InstOrigin, SrcLoc, ErrCtxt)
697 = OccurrenceOf Id -- Occurrence of an overloaded identifier
701 | DataDeclOrigin -- Typechecking a data declaration
703 | InstanceDeclOrigin -- Typechecking an instance decl
705 | LiteralOrigin RenamedHsOverLit -- Occurrence of a literal
707 | PatOrigin RenamedPat
709 | ArithSeqOrigin RenamedArithSeqInfo -- [x..], [x..y] etc
711 | SignatureOrigin -- A dict created from a type signature
712 | Rank2Origin -- A dict created when typechecking the argument
713 -- of a rank-2 typed function
715 | DoOrigin -- The monad for a do expression
717 | ClassDeclOrigin -- Manufactured during a class decl
719 | InstanceSpecOrigin Class -- in a SPECIALIZE instance pragma
722 -- When specialising instances the instance info attached to
723 -- each class is not yet ready, so we record it inside the
724 -- origin information. This is a bit of a hack, but it works
725 -- fine. (Patrick is to blame [WDP].)
727 | ValSpecOrigin Name -- in a SPECIALIZE pragma for a value
729 -- Argument or result of a ccall
730 -- Dictionaries with this origin aren't actually mentioned in the
731 -- translated term, and so need not be bound. Nor should they
732 -- be abstracted over.
734 | CCallOrigin String -- CCall label
735 (Maybe RenamedHsExpr) -- Nothing if it's the result
736 -- Just arg, for an argument
738 | LitLitOrigin String -- the litlit
740 | UnknownOrigin -- Help! I give up...
744 pprInstLoc :: InstLoc -> SDoc
745 pprInstLoc (orig, locn, ctxt)
746 = hsep [text "arising from", pp_orig orig, text "at", ppr locn]
748 pp_orig (OccurrenceOf id)
749 = hsep [ptext SLIT("use of"), quotes (ppr id)]
750 pp_orig (LiteralOrigin lit)
751 = hsep [ptext SLIT("the literal"), quotes (ppr lit)]
752 pp_orig (PatOrigin pat)
753 = hsep [ptext SLIT("the pattern"), quotes (ppr pat)]
754 pp_orig (InstanceDeclOrigin)
755 = ptext SLIT("an instance declaration")
756 pp_orig (ArithSeqOrigin seq)
757 = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)]
758 pp_orig (SignatureOrigin)
759 = ptext SLIT("a type signature")
760 pp_orig (Rank2Origin)
761 = ptext SLIT("a function with an overloaded argument type")
763 = ptext SLIT("a do statement")
764 pp_orig (ClassDeclOrigin)
765 = ptext SLIT("a class declaration")
766 pp_orig (InstanceSpecOrigin clas ty)
767 = hsep [text "a SPECIALIZE instance pragma; class",
768 quotes (ppr clas), text "type:", ppr ty]
769 pp_orig (ValSpecOrigin name)
770 = hsep [ptext SLIT("a SPECIALIZE user-pragma for"), quotes (ppr name)]
771 pp_orig (CCallOrigin clabel Nothing{-ccall result-})
772 = hsep [ptext SLIT("the result of the _ccall_ to"), quotes (text clabel)]
773 pp_orig (CCallOrigin clabel (Just arg_expr))
774 = hsep [ptext SLIT("an argument in the _ccall_ to"), quotes (text clabel) <> comma,
775 text "namely", quotes (ppr arg_expr)]
776 pp_orig (LitLitOrigin s)
777 = hsep [ptext SLIT("the ``literal-literal''"), quotes (text s)]
778 pp_orig (UnknownOrigin)
779 = ptext SLIT("...oops -- I don't know where the overloading came from!")