April 2013 - ghc-tickets

[GHC] #7820: Installing profiling library BREAKS non-profiling executable
by GHC 22 Apr '13

22 Apr '13

#7820: Installing profiling library BREAKS non-profiling executable --------------------------+------------------------------------------------- Reporter: rrnewton | Owner: Type: bug | Status: new Priority: normal | Component: Compiler Version: 7.6.2 | Keywords: profiling Os: Linux | Architecture: x86_64 (amd64) Failure: Runtime crash | Blockedby: Blocking: | Related: --------------------------+------------------------------------------------- I am trying to work through problems with different GHC "ways" so that I can broadly deploy a library of foreign primops for lockfree data structures. Here's the package I am testing at the moment: https://github.com/rrnewton/haskell-lockfree- queue/tree/5d990fe43a983fc5ed32c3f58cb2e59df71b00b6/AtomicPrimops Here is a recipe for reproducing the bug from within that directory. Both of these build modes work FINE: (cabal install --enable-library-profiling; cd testing; make prof; ./Test_prof.exe) (cabal install --disable-library-profiling; cd testing; make; ./Test_threaded.exe) That is, building both library and executable with profiling, or without profiling, works fine. But then this creates an executable that segfaults: (cabal install --enable-library-profiling; cd testing; make; ./Test_threaded.exe) At runtime the call to the .cmm-defined foreign primop just returns zero, and then the process segfaults when it tries to use that as a Haskell value. But my understanding is that --enable-library-profiling should just add extra binaries to .cabal and NOT change the behavior of the non-profiling binaries. Yet I can confirm that I see slightly different binary sizes with the non- profiling .o and .a files installed in ~/.cabal/lib depending on whether --enable-library-profiling is activated. Perhaps this in itself is a cabal bug, but I haven't tracked down exactly what the difference is yet. I have confirmed the above behavior under: * Mac OS (ghc 7.4.2 and 7.6.2) * Linux, RHEL 6 (ghc 7.4.2 and 7.6.2) -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7820> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 3

[GHC] #7849: Error on pattern matching of an existential whose context includes a type function
by GHC 22 Apr '13

22 Apr '13

#7849: Error on pattern matching of an existential whose context includes a type function -----------------------------+---------------------------------------------- Reporter: guest | Owner: Type: bug | Status: new Priority: normal | Component: Compiler (Type checker) Version: 7.4.2 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- The following code {{{ {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE ExistentialQuantification #-} {-# LANGUAGE GADTs #-} module Ex where import Data.IORef class SUBJ subj where type SUBJ_Obs subj :: * unsubscribe' :: subj -> SUBJ_Obs subj -> IO () data ASubj obs = forall subj. (SUBJ subj, SUBJ_Obs subj ~ obs) => ASubj subj -- data ASubj obs = forall subj. (SUBJ subj) => ASubj subj (obs -> SUBJ_Obs subj) class OBS obs where subscribed :: obs -> ASubj obs -> IO () withdraw :: obs -> IO () -- The implementation of Obs data Obs = Obs{obs_subjects :: IORef [ASubj Obs]} instance OBS Obs where subscribed obs subj = modifyIORef (obs_subjects obs) (subj:) withdraw obs = do subjs <- readIORef (obs_subjects obs) writeIORef (obs_subjects obs) [] mapM_ (\ (ASubj subj) -> unsubscribe' subj obs) subjs -- mapM_ (\ (ASubj subj cast) -> unsubscribe' subj (cast obs)) subjs }}} gives a rather obscure type error {{{ Couldn't match type `b0' with `()' `b0' is untouchable inside the constraints (SUBJ subj, SUBJ_Obs subj ~ Obs) bound at a pattern with constructor ASubj :: forall obs subj. (SUBJ subj, SUBJ_Obs subj ~ obs) => subj -> ASubj obs, in a lambda abstraction In the pattern: ASubj subj In the first argument of `mapM_', namely `(\ (ASubj subj) -> unsubscribe' subj obs)' In a stmt of a 'do' block: mapM_ (\ (ASubj subj) -> unsubscribe' subj obs) subjs -} }}} It is not even clear what b0 is: the code has no type variable named b. Incidentally, if I use the explicit cast (as in the commented out declaration of ASubj) and change the last line of withdraw accordingly (as shown in the commented out line), the code compiles. It seems that what I am trying to accomplish is reasonable. Incidentally, why GHC insists on the extension GADTs given that I already specified ExistentialQuantification? It seems when opening amn existential GADTs extension must be present. It seems ExistentialQuantification no longer has any point? -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7849> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 1

[GHC] #7786: strange errors when deducing constraints
by GHC 22 Apr '13

22 Apr '13

#7786: strange errors when deducing constraints -----------------------------+---------------------------------------------- Reporter: heisenbug | Owner: Type: bug | Status: new Priority: normal | Component: Compiler Version: 7.7 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- Please load attached file in ghci and observe the resulting error message. I have added my commentaries inline to what appears fishy to me. All may technically be ok, but look quite confusing. {{{ [1 of 1] Compiling Main ( pr7786.hs, interpreted ) pr7786.hs:74:22: Couldn't match type `Intersect [KeySegment] (BuriedUnder sub k ('Empty [KeySegment])) inv' with 'Empty [KeySegment] Inaccessible code in a pattern with constructor Nil :: forall (k :: BOX). Sing (Inventory k) ('Empty k), in a pattern binding in 'do' block }}} Yes, ok, (Nil :: Sing Empty) does not unify with (forall xxx. Nil :: Sing xxx). {{{ Relevant bindings include addSub :: Database inv -> Sing [KeySegment] k -> Database sub -> Maybe (Database (BuriedUnder sub k inv)) (bound at pr7786.hs:74:1) db :: Database inv (bound at pr7786.hs:74:8) k :: Sing [KeySegment] k (bound at pr7786.hs:74:11) sub :: Database sub (bound at pr7786.hs:74:13) In the pattern: Nil In the pattern: Nil :: Sing xxx In a stmt of a 'do' block: Nil :: Sing xxx <- return (buryUnder (dbKeys sub) k Nil `intersectPaths` dbKeys db) pr7786.hs:78:31: Could not deduce (Intersect [KeySegment] (BuriedUnder sub k ('Empty [KeySegment])) inv ~ 'Empty [KeySegment]) from the context (Intersect [KeySegment] (BuriedUnder sub k ('Empty [KeySegment])) inv ~ 'Empty [KeySegment]) }}} This one is highly disturbing. I think the user should never see such a message. Scary. ''This is the reason for the ticket''. {{{ bound by a pattern with constructor Nil :: forall (k :: BOX). Sing (Inventory k) ('Empty k), in a pattern binding in 'do' block at pr7786.hs:74:22-24 Relevant bindings include addSub :: Database inv -> Sing [KeySegment] k -> Database sub -> Maybe (Database (BuriedUnder sub k inv)) (bound at pr7786.hs:74:1) db :: Database inv (bound at pr7786.hs:74:8) k :: Sing [KeySegment] k (bound at pr7786.hs:74:11) sub :: Database sub (bound at pr7786.hs:74:13) In the second argument of `($)', namely `Sub db k sub' In a stmt of a 'do' block: return $ Sub db k sub In the expression: do { Nil :: Sing xxx <- return (buryUnder (dbKeys sub) k Nil `intersectPaths` dbKeys db); return $ Sub db k sub } Failed, modules loaded: none. }}} '''Now comment line 74 and uncomment l. 75 and reload:''' {{{ pr7786.hs:75:22: Couldn't match type `Intersect [KeySegment] (BuriedUnder sub k ('Empty [KeySegment])) inv' with `Intersect [KeySegment] (BuriedUnder sub1 k1 ('Empty [KeySegment])) inv1' }}} Hmm, I vaguely understand why those new degrees of freedom arise. {{{ NB: `Intersect' is a type function, and may not be injective }}} Probably irrelevant, no need to backwards guess here, as we have -XScopedTypeVariables turned on. {{{ The type variables `sub', `k', `inv' are ambiguous Expected type: Sing (Inventory [KeySegment]) (Intersect [KeySegment] (BuriedUnder sub1 k1 ('Empty [KeySegment])) inv1) Actual type: Sing (Inventory [KeySegment]) (Intersect [KeySegment] (BuriedUnder sub k ('Empty [KeySegment])) inv) Relevant bindings include addSub :: Database inv1 -> Sing [KeySegment] k1 -> Database sub1 -> Maybe (Database (BuriedUnder sub1 k1 inv1)) (bound at pr7786.hs:74:1) db :: Database inv1 (bound at pr7786.hs:74:8) k :: Sing [KeySegment] k1 (bound at pr7786.hs:74:11) sub :: Database sub1 (bound at pr7786.hs:74:13) In the pattern: Nil :: Sing ((sub `BuriedUnder` k) Empty `Intersect` inv) In a stmt of a 'do' block: Nil :: Sing ((sub `BuriedUnder` k) Empty `Intersect` inv) <- return (buryUnder (dbKeys sub) k Nil `intersectPaths` dbKeys db) In the expression: do { Nil :: Sing ((sub `BuriedUnder` k) Empty `Intersect` inv) <- return (buryUnder (dbKeys sub) k Nil `intersectPaths` dbKeys db); return $ Sub db k sub } Failed, modules loaded: none. }}} '''Now comment line 75 and uncomment l. 76 and reload:''' {{{ [1 of 1] Compiling Main ( pr7786.hs, interpreted ) pr7786.hs:76:51: Couldn't match type `Intersect [KeySegment] (BuriedUnder sub k ('Empty [KeySegment])) inv' with 'Empty [KeySegment] Expected type: Sing (Inventory [KeySegment]) ('Empty [KeySegment]) Actual type: Sing (Inventory [KeySegment]) (Intersect [KeySegment] (BuriedUnder sub k ('Empty [KeySegment])) inv) }}} Err... But (Nil :: Sing Empty) is ''exactly'' the annotation on the Nil constructor in the GADT definition! {{{ Relevant bindings include addSub :: Database inv -> Sing [KeySegment] k -> Database sub -> Maybe (Database (BuriedUnder sub k inv)) (bound at pr7786.hs:74:1) db :: Database inv (bound at pr7786.hs:74:8) k :: Sing [KeySegment] k (bound at pr7786.hs:74:11) sub :: Database sub (bound at pr7786.hs:74:13) In the first argument of `return', namely `(buryUnder (dbKeys sub) k Nil `intersectPaths` dbKeys db)' In a stmt of a 'do' block: Nil :: Sing Empty <- return (buryUnder (dbKeys sub) k Nil `intersectPaths` dbKeys db) In the expression: do { Nil :: Sing Empty <- return (buryUnder (dbKeys sub) k Nil `intersectPaths` dbKeys db); return $ Sub db k sub } Failed, modules loaded: none. }}} '''Now comment line 76 and uncomment l. 77 and reload:''' All is dandy! -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7786> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 4

[GHC] #7856: matter for release 7.6.3 relieved
by GHC 22 Apr '13

22 Apr '13

#7856: matter for release 7.6.3 relieved -----------------------------+---------------------------------------------- Reporter: AngelaRamirez | Owner: Type: bug | Status: new Priority: normal | Component: Compiler Version: 7.6.3 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- Безопасность и абсолютная конфиденциальность на web-сайте секс-услуг. В наше время интернет – это не просто средство, предназначенное для обмена данными, это еще и хороший помощник всем, кто желает развлечься. Web-порталы, посвященные предоставлению секс-услуг, способны сделать досуг незабываемым и максимально интересным. Ведь не существует границы фантазиям. На предоставляющем услуги интимного характера веб-портале подобраны наилучшие проститутки киева. Здесь также есть возможность рассмотреть любую девушку и ознакомиться с ценой, правилами и предлагаемыми услугами. Конечно же, к интим-услугам проститутки киев это будет либо какой-нибудь другой город захотят прибегнуть многие мужчины. А причин для этого может быть огромнейшее множество: - избавиться от комплексов;- отдохнуть телом и душой;- приобрести новый опыт в сексе;- сделать сюрприз партнерам либо другу; - ощутить себя желанным;- заняться своего рода экспериментами. Некоторые гости столицы, приезжая сюда для ознакомления с местными достопримечательностями либо по делам стремятся воспользоваться сексуальными услугами. Ведь Киев проститутки в любое время составят приятную и веселую компанию и не дадут гостям умирать от скуки. Они без проблем смогут приехать на час, два либо же остаться на всю ночь. Для того, чтобы воспользоваться услугами прекрасных и красивых дам достаточно лишь посетить web-сайт, отыскать приглянувшуюся девушку, а затем связаться по контактному телефону с представителем. Потребуется также указать, где вы предпочитаете с девушкой встретиться и период времени, в течение которого вы будете пользоваться сексуальными услугами. Все пожелания будут строго соблюдены. Огромнейшим плюсом данного сервиса считается то, что если вдруг необходимы проститутки в киеве, то не понадобится в поисках сомнительных услуг куда-либо выезжать. В любое время можно воспользоваться услугами надежной и проверенной компании. Имея какое-то количество свободного времени, возможно рассмотреть все анкеты проституток киева. Следовательно, по каким-то определенным показателям возможно подобрать девочек, к интим-услугам которых можно будет прибегать постоянно. Оказывающие интим-услуги компании отводят уровню обслуживания важную роль. Мужчина должен оставаться доволен всегда. Только лишь в этом случае приглашать девочек он станет вновь. Если же мужчину очень заинтересовала какая-то [http://escort-models.com проститутка киев] посещает он периодически, то и к услугам он ее станет прибегать всегда. Притом ему могут предоставляться скидки. Востребованность интим-услуг постоянно возрастает. Это понятно, потому как сегодня самая древняя профессия стала более доступной. Многие интернет-страницы пестрят самыми разнообразными разновидностями интимных удовольствий, к примеру, веб-камеры, чаты. Однако нет ничего лучше вызова девушки на дом, где есть возможность как отдохнуть телом, так и мило пообщаться с привлекательной и приятной девушкой. Можно быть уверенным в том, что при обращении в надежное и проверенное агентство, услуги осуществляются на должном уровне, вечер будет потрясающим, и все данные о клиенте останутся конфиденциальными. Воспользоваться услугами проститутки можно для себя, а можно также сделать приятное партнерам по бизнесу либо же скучающему другу. Подобные сюрпризы будут высоко оценены. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7856> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Re: [GHC] #7359: unix-2.6.0.0 fails to install on mac os x with 7.4.* (works with 7.6.1)
by GHC 21 Apr '13

21 Apr '13

#7359: unix-2.6.0.0 fails to install on mac os x with 7.4.* (works with 7.6.1) -------------------------------+-------------------------------------------- Reporter: AndreasVoellmy | Owner: igloo Type: bug | Status: new Priority: highest | Milestone: 7.6.3 Component: libraries/unix | Version: 7.4.1 Keywords: unix package | Os: MacOS X Architecture: x86_64 (amd64) | Failure: Other Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | -------------------------------+-------------------------------------------- Comment(by MtnViewMark): The unix package is supplied with GHC. You can't, in general, just use a different version. Haskell Platform 2012.4 ships with GHC 7.4.1, which includes unix-2.5.1.1. I wouldn't expect unix-2.6.x.y to work with GHC 7.4.1 at all. Of course unix-2.6.x.y works with GHC 7.6.z, as that is the version of GHC that distributes with it. I'm curious what caused the OP's system to think it needed unix-2.6.0.0. I'm also wondering if I should be reading something into "I installed ghc from the haskell-platform" - does that mean they installed HP whole, or did some surgery to install just GHC? -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7359#comment:10> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

[GHC] #7626: Add common utility variants of trace to Debug.Trace
by GHC 21 Apr '13

21 Apr '13

#7626: Add common utility variants of trace to Debug.Trace -----------------------------+---------------------------------------------- Reporter: chrisseaton | Owner: Type: feature request | Status: new Priority: normal | Component: libraries/base Version: 7.6.1 | Keywords: trace Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- As discussed on the libraries list. http://www.haskell.org/pipermail/libraries/2013-January/019319.html 'traceId' traces a value, and then returns that same value. This avoids the common case of 'trace a a'. {{{ traceId :: String -> String traceId a = trace a a }}} 'traceM' runs 'trace' and returns unit in an arbitrary monad. This is useful for writing traces in do-notation, as each can sit on their own line. {{{ traceM :: (Monad m) => String -> m () traceM string = trace string $ return () }}} For example: {{{ ... = do x <- ... traceM $ "x: " ++ show x y <- ... ... }}} That application of 'traceM' there can be temporarily commented out with a simple line comment. Finally, equivalents of 'traceShow' for those two functions. {{{ traceShowId :: (Show a) => a -> a traceShowId a = trace (show a) a }}} {{{ traceShowM :: (Show a, Monad m) => a -> m () traceShowM = traceM . show }}} Advantages: I use these functions in my code all the time. When I discussed it on the libraries list there were several enthusiastic +1s of people doing the same. Disadvantages: The documentation in the patch makes it clear that traceM does not actually add a trace action to the monad you're using, which is a potential point of confusion (http://www.haskell.org/pipermail/libraries/2013-January/019322.html) I had originally suggested that 'traceIO == traceM', but it turns out this is not so. Henning Thielemann suggested that 'traceM' was better achieved with directly using 'trace' and 'printf' (http://www.haskell.org/pipermail/libraries/2013-January/019320.html) Of course, any function can be replaced with its RHS, and whether or not the user uses 'show' or 'printf' or whatever is orthogonal. I haven't written any tests, as it's all output generating code, so I'm really not sure how that's tested in GHC - sorry. Status of patch: Applies against base 3b51b741f45d4d85e79b2128d00479ce230f72f2 and compiles with GHC 388e1e825f79f2d16536fc583a48e5ce9c191b06. I've run a full GHC compile cycle with it without problem. Includes documentation. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7626> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 3

[GHC] #7817: Moving basic functions
by GHC 21 Apr '13

21 Apr '13

#7817: Moving basic functions -----------------------------+---------------------------------------------- Reporter: quchen | Owner: Type: feature request | Status: new Priority: normal | Component: libraries/base Version: 7.6.2 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- '''1.''' Add the `infixl 4` operator `($>) = flip (<$)` to Data.Functor. '''2.''' Move `Control.Monad.void` to `Data.Functor`, and re-export it from `Control.Monad` for compatibility. In addition, replace the deprecated `Foreign.Marshal.Error.void` with a re-export as well. The mailing list discussion is here: http://markmail.org/message/cqdlle4l6npxs3jn -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7817> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 2

[GHC] #7852: panic: kindFunResult ghc-prim:GHC.Prim.*{(w) tc 34d}
by GHC 21 Apr '13

21 Apr '13

#7852: panic: kindFunResult ghc-prim:GHC.Prim.*{(w) tc 34d} ----------------------------------------+----------------------------------- Reporter: igloo | Owner: Type: bug | Status: new Priority: high | Milestone: 7.8.1 Component: Compiler (Type checker) | Version: 7.6.3 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: None/Unknown Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | ----------------------------------------+----------------------------------- This code: {{{ f :: (Num Int => Num) () => () f = undefined }}} make ghc panic: {{{ $ ghci q.hs GHCi, version 7.7.20130421: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. [1 of 1] Compiling Main ( q.hs, interpreted ) ghc-stage2: panic! (the 'impossible' happened) (GHC version 7.7.20130421 for x86_64-unknown-linux): kindFunResult ghc-prim:GHC.Prim.*{(w) tc 34d} Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug > }}} -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7852> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 3

[GHC] #7740: Remove direct cabal imports in Linker and Finder modules
by GHC 21 Apr '13

21 Apr '13

#7740: Remove direct cabal imports in Linker and Finder modules -----------------------------+---------------------------------------------- Reporter: rodlogic | Owner: Type: bug | Status: new Priority: normal | Component: Compiler Version: 7.7 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: Other | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- This is a low priority change, that mostly marks my first contribution :-) See pull request and additional details here: https://github.com/ghc/ghc/pull/6 -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7740> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 2

[GHC] #7761: iOS patch no 16: pass the correct -Dxxx_HOST_ARCH and -Dxxx_HOST_OS to hsc2hs by stage
by GHC 21 Apr '13

21 Apr '13

#7761: iOS patch no 16: pass the correct -Dxxx_HOST_ARCH and -Dxxx_HOST_OS to hsc2hs by stage ------------------------------+--------------------------------------------- Reporter: StephenBlackheath | Owner: Type: feature request | Status: new Priority: normal | Component: Compiler Version: 7.7 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Blockedby: Blocking: 7724 | Related: ------------------------------+--------------------------------------------- Currently hsc2hs always gets the build host's values, even when cross compiling. This patch makes it pass the correct values for the stage. There is no actual build failure that results from this being wrong, but it is only a matter of time before something breaks. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7761> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 4