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Re: [GHC] #7766: equality constraints exposed by patterns mess up constraint inference
by Gabor Greif 13 Mar '13

13 Mar '13

Hi Simon, okay, I see how a type signature will help in that case, but it is unclear where to add one in this (even simpler) example: {-# LANGUAGE GADTs, DataKinds, KindSignatures #-} data Nat = S Nat | Z data Nat' (n :: Nat) where S' :: Nat' n -> Nat' (S n) Z' :: Nat' Z main :: IO () main = do case S' Z' of (S' Z') -> putStrLn "yep" -- see error message below... -- _ -> putStrLn "yep" -- works! return () {- [1 of 1] Compiling Main ( pr7766.hs, pr7766.o ) pr7766.hs:11:23: Couldn't match type `a0' with `()' `a0' is untouchable inside the constraints (n ~ 'Z) bound by a pattern with constructor Z' :: Nat' 'Z, in a case alternative at pr7766.hs:11:16-17 Expected type: IO a0 Actual type: IO () In the return type of a call of `putStrLn' In the expression: putStrLn "yep" In a case alternative: (S' Z') -> putStrLn "yep" -} Can we reopen the PR with this test? (Distilled from real code I have and which fails as of recently.) Thanks and cheers, Gabor On 3/13/13, GHC <cvs-ghc(a)haskell.org> wrote: > #7766: equality constraints exposed by patterns mess up constraint > inference > ----------------------------------------+----------------------------------- > Reporter: heisenbug | Owner: > Type: bug | Status: closed > Priority: normal | Milestone: > Component: Compiler | Version: 7.7 > Resolution: invalid | Keywords: > Os: Unknown/Multiple | Architecture: Unknown/Multiple > Failure: GHC rejects valid program | Difficulty: Unknown > Testcase: | Blockedby: > Blocking: | Related: > ----------------------------------------+----------------------------------- > Changes (by simonpj): > > * status: new => closed > * difficulty: => Unknown > * resolution: => invalid > > > Comment: > > This is by design. Type inference in the presence of GADTs is tricky! > > If you give the signature `main :: IO ()` it works fine. But here you are > asking GHC to ''infer'' the type of `main`. (Remember, Haskell doesn't > insist on `IO ()`; the `main` function can have type `IO Char`.) > > Becuase you are pattern matching against GADTs there are equalities in > scope, so GHC declines to contrain the type of `main`. In this particular > case there is only one answer, but that's very hard to figure out, so we > fail conservatively. > > Bottom line: use type signatures when pattern matching on GADTs. > > Simon > > -- > Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7766#comment:1> > GHC <http://www.haskell.org/ghc/> > The Glasgow Haskell Compiler >

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RE: [GHC] #6135: Unboxed Booleans
by Simon Peyton-Jones 13 Mar '13

13 Mar '13

Ben Would you like to take a look, since you initiated this :-). We need a definite win to make it worth it. Simon | -----Original Message----- | From: ghc-tickets-bounces(a)haskell.org [mailto:ghc-tickets- | bounces(a)haskell.org] On Behalf Of GHC | Sent: 13 March 2013 14:19 | Cc: ghc-tickets(a)haskell.org | Subject: Re: [GHC] #6135: Unboxed Booleans | | #6135: Unboxed Booleans | ---------------------------------+-------------------------------------- | ---------------------------------+---- | Reporter: benl | Owner: jstolarek | Type: feature request | Status: new | Priority: normal | Milestone: 7.8.1 | Component: Compiler | Version: 7.4.1 | Keywords: | Os: Unknown/Multiple | Architecture: Unknown/Multiple | Failure: None/Unknown | Difficulty: Unknown | Testcase: | Blockedby: | Blocking: | Related: #605 | | ---------------------------------+-------------------------------------- | ---------------------------------+---- | | Comment(by jstolarek): | | I implemented a prototype version of new comparison primops. They | compare two `Int#`s but as a result they return either `0#` (denoting | False) or `1#` (denoting True) instead of returning a `Bool`. Now the | results of comparing can be combined using bitwise `orI#`, `andI#`, | `xorI#` and `notI#` primops, which addresses the original problem that | was reported (at least partially). I'm attaching patches for GHC and | the testsuite (includes some cleanup of my other code for testing | primops). These patches are for review and discussion purposes - they | are not yet ready for integration because they don't contain primops | for comparing values of type `Word#`, `Float#` and `Double#`. I will | implement comparisons for these types once I am certain that I got | things right with `Int#`. | Feedback will be much appreciated. | | -- | Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6135#comment:21> | GHC <http://www.haskell.org/ghc/> | The Glasgow Haskell Compiler | | _______________________________________________ | ghc-tickets mailing list | ghc-tickets(a)haskell.org | http://www.haskell.org/mailman/listinfo/ghc-tickets

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RE: [commit: testsuite] master: Revert "Accept unicode quotes in T2507" (937c039)
by Simon Peyton-Jones 13 Mar '13

13 Mar '13

Interesting. The test failed on my Windows box; I thought it was an oversight. Now you've reverted, it'll fail again. What to do? Simon | -----Original Message----- | From: ghc-commits-bounces(a)haskell.org [mailto:ghc-commits- | bounces(a)haskell.org] On Behalf Of Ian Lynagh | Sent: 10 March 2013 15:46 | To: ghc-commits(a)haskell.org | Subject: [commit: testsuite] master: Revert "Accept unicode quotes in T2507" | (937c039) | | Repository : ssh://darcs.haskell.org//srv/darcs/testsuite | | On branch : master | | http://hackage.haskell.org/trac/ghc/changeset/937c0399bff9a867fccd8b6e7a63f8 | f25e7b6300 | | >--------------------------------------------------------------- | | commit 937c0399bff9a867fccd8b6e7a63f8f25e7b6300 | Author: Ian Lynagh <ian(a)well-typed.com> | Date: Sun Mar 10 15:41:48 2013 +0000 | | Revert "Accept unicode quotes in T2507" | | T2507 sets LC_ALL=C, so doesn't run in a Unicode locale, and shouldn't | have unicode quotes. | | >--------------------------------------------------------------- | | tests/driver/T2507.stderr | 4 ++-- | 1 files changed, 2 insertions(+), 2 deletions(-) | | diff --git a/tests/driver/T2507.stderr b/tests/driver/T2507.stderr index | 68d57e3..925a870 100644 | --- a/tests/driver/T2507.stderr | +++ b/tests/driver/T2507.stderr | @@ -1,5 +1,5 @@ | | T2507.hs:5:7: | - Couldn't match expected type ‛Int’ with actual type ‛()’ | + Couldn't match expected type `Int' with actual type `()' | In the expression: () | - In an equation for ‛foo’: foo = () | + In an equation for `foo': foo = () | |

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Snapshot release and DPH
by Manuel M T Chakravarty 13 Mar '13

13 Mar '13

Ian, Simon just told us on the phone that you agreed to make a snapshot release of GHC (instead of a full release). In that snapshot release, could you include DPH (and associated libraries)? That is, make a snapshot of the entire HEAD instead of just the parts that go into a full release. The reason is that we would like to include DPH into the release. However, our usual approach of distributing the DPH libraries separately via Hackage will not work for a snapshot as the libraries on Hackage will likely not build with the snapshot. (This should be fine as the reason for not having DPH in a full release was to avoid sneaking it into the Haskell Platform with GHC, but a snapshot doesn't go into the Platform anyway.) Manuel

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SRC_HC_OPTS instead of HC_OPTS in nofib shootout/ & fibon/?
by Nicolas Frisby 12 Mar '13

12 Mar '13

(cc'd ghc-devs) Hi Johan and David. I've noticed that you used "HC_OPTS += -O2 ..." in the Makefiles for the shootout programs, eg in your commits a735c7a1 and a9cdc8b1. I'm not seeing a way to override those options when invoking make on the command line. I've been using something like EXTRA_HC_OPTS="-O1 ..." in order to build the tests *without* -O2, but $(EXTRA_HC_OPTS) comes before $(HC_OPTS) on the generated command line; from ghc-opts.mk: HC_OPTS = $(BOOTSTRAPPING_PACKAGE_CONF_HC_OPTS) $(SRC_HC_OPTS) $(WAY$(_way)_HC_OPTS) $($*_HC_OPTS) $(EXTRA_HC_OPTS) Thus I can't turn -O2 off. I want to turn -O2 off, eg, since if I cause some horrific change in the code, I want to see it, even if -O2 would undo it. >From ghc-opts.mk, again: # SRC_P_OPTS Source-tree options for P I suspect the options you put in HC_OPTS would better fit in SRC_HC_OPTS. What do you think? Thanks.

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Resource limits for Haskell
by Edward Z. Yang 12 Mar '13

12 Mar '13

Ever wanted to write this? -- | Forks a thread, but kills it if it has more than 'limit' -- bytes resident on the heap. forkIOWithSpaceLimit :: IO () -> {- limit -} Int -> IO ThreadId I have a proposal (and some unpublished experimental patches) which do just that. Check it out at: http://hackage.haskell.org/trac/ghc/wiki/Commentary/ResourceLimits Comments, bikeshedding and critique appreciated. Cheers, Edward

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Re: Error while compiling cross-compiler
by Eric Schug 11 Mar '13

11 Mar '13

Ok using git HEAD, which got me further, but now errors when compiling terminfo. Its having problems locating the headers and libraries for cursers/ncursers Although, I have the host headers and libraries, but I expect it is searching for the target versions. These I can pull from my raspberry pi, but I am not sure where to put them such that the cross compiler will find them. On 03/08/13 20:19, Austin Seipp wrote: > 7.6.2 doesn't really support cross compilation. The bulk of the work > has been done in the git repository. Any artifacts of cross > compilation support in released tarballs can be ignored. > > Please do try the steps on the wiki page, using a copy of HEAD from > git. I tried this a week or two ago and encountered no difficulties if > my memory serves correctly. > > Sent from my iPhone^H^H^H^H^HPortable Turing machine > > On Mar 8, 2013, at 6:34 PM, Eric Schug<schugschug(a)gmail.com> wrote: > >> I am following the instructions for creating a cross compiler for Raspberry Pi, but I get a file does not exist error during stage 1 (see below). >> The basic steps I have taken are >> apt-get install llvm >> git clone https://github.com/raspberrypi/tools.git >> export rpitools=`pwd`/rpitools/ >> export tools=`pwd`/tools >> export PATH=$PATH:$tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin >> wget http://www.haskell.org/ghc/dist/7.6.2/ghc-7.6.2-src.tar.bz2 >> tar jxvf ghc-7.6.2-src.tar.bz2 >> cd ghc-7.6.2/ >> ./configure --target=arm-linux-gnueabihf --prefix=$rpitools >> make >> >> make -r --no-print-directory -f ghc.mk phase=1 phase_1_builds >> CROSS_COMPILE="arm-unknown-linux-gnueabihf-" "inplace/bin/ghc-cabal" configure --with-ghc="/media/2612bbee-1ea0-43dd-82f4-c7e7d3fe634b_/eric/haskell/ghc-7.6.2/inplace/bin/ghc-stage1" --with-ghc-pkg="/media/2612bbee-1ea0-43dd-82f4-c7e7d3fe634b_/eric/haskell/ghc-7.6.2/inplace/bin/ghc-pkg" --flag=include-ghc-prim --enable-library-for-ghci --configure-option=CFLAGS=" -fno-stack-protector " --configure-option=LDFLAGS=" -Wl,--hash-size=31 -Wl,--reduce-memory-overheads " --configure-option=CPPFLAGS=" " --with-gcc="/media/2612bbee-1ea0-43dd-82f4-c7e7d3fe634b_/eric/haskell/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-gcc" --configure-option=--with-cc="/media/2612bbee-1ea0-43dd-82f4-c7e7d3fe634b_/eric/haskell/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-gcc" --with-ar="/usr/bin/ar" --with-ranlib="true" --with-alex="/usr/bin/alex" --with-happy="/usr/bin/happy" -- dist-install libraries/ghc-prim >> Configuring ghc-prim-0.3.0.0... >> ghc-cabal: /tmp/22147.o: does not exist >> make[1]: *** [libraries/ghc-prim/dist-install/package-data.mk] Error 1 >> make: *** [all] Error 2 >> >> I am not sure if I need to create a mk/build.mk file using the mk/build.mk.sample, but when I do so and add the line >> Stage1Only = YES >> I still get the same error only with a different temp filename. >> >> >> _______________________________________________ >> ghc-devs mailing list >> ghc-devs(a)haskell.org >> http://www.haskell.org/mailman/listinfo/ghc-devs

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Unicode support for Haddock
by Max Bolingbroke 11 Mar '13

11 Mar '13

Hi GHCers, I recently ran into a problem where Haddock does not correctly handle Unicode in doc comments. So for example with this file: """ module Example where -- | 好 ok :: Int -> Int ok x = x -- | 个 misinterp :: Int -> Int misinterp _ = (-1) -- | 漢 failure :: Int -> Int failure x = x-1 """ Current versions of Haddock will output the documentation for "ok" correctly, will output an empty bulleted list as the documentation for "misinterp" and not output any documentation at all for "failure" (echoing a warning to stderr instead). This is kind of sad. There is a very old open ticket about this issue: http://trac.haskell.org/haddock/ticket/20. The patches I've attached to that ticket fix the problem by using the native Unicode support in Alex 3. I've also attached to the ticket a patch which makes the necessary changes to GHC's build system required to build this new Haddock correctly. Do these patches seem OK? Is it fine to insist on Alex 3? I think it was released in 2011 so I think by now we can assume that it is available on all machines that will want to build GHC. If this patch is accepted, at some point we might want to think about switching to Alex 3's unicode support in GHC's own lexer rather than relying on the current hacks. My patches do not make any change along those lines. Cheers, Max

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Trac source browser not working
by Simon Marlow 10 Mar '13

10 Mar '13

I tried to follow a link to a commit on Trac today, and got an error: internal error (got unexpected object kind 'commit') The link I followed: http://hackage.haskell.org/trac/ghc/changeset/109a1e53287f50103e8a5b5922759… This was working before, has anything changed recently that would break it? I tried browsing to a couple of other commits and got the same error, so it doesn't seem specific to that commit. Cheers, Simon

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Error while compiling cross-compiler
by Eric Schug 09 Mar '13

09 Mar '13

I am following the instructions for creating a cross compiler for Raspberry Pi, but I get a file does not exist error during stage 1 (see below). The basic steps I have taken are apt-get install llvm git clone https://github.com/raspberrypi/tools.git export rpitools=`pwd`/rpitools/ export tools=`pwd`/tools export PATH=$PATH:$tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin wget http://www.haskell.org/ghc/dist/7.6.2/ghc-7.6.2-src.tar.bz2 tar jxvf ghc-7.6.2-src.tar.bz2 cd ghc-7.6.2/ ./configure --target=arm-linux-gnueabihf --prefix=$rpitools make make -r --no-print-directory -f ghc.mk phase=1 phase_1_builds CROSS_COMPILE="arm-unknown-linux-gnueabihf-" "inplace/bin/ghc-cabal" configure --with-ghc="/media/2612bbee-1ea0-43dd-82f4-c7e7d3fe634b_/eric/haskell/ghc-7.6.2/inplace/bin/ghc-stage1" --with-ghc-pkg="/media/2612bbee-1ea0-43dd-82f4-c7e7d3fe634b_/eric/haskell/ghc-7.6.2/inplace/bin/ghc-pkg" --flag=include-ghc-prim --enable-library-for-ghci --configure-option=CFLAGS=" -fno-stack-protector " --configure-option=LDFLAGS=" -Wl,--hash-size=31 -Wl,--reduce-memory-overheads " --configure-option=CPPFLAGS=" " --with-gcc="/media/2612bbee-1ea0-43dd-82f4-c7e7d3fe634b_/eric/haskell/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-gcc" --configure-option=--with-cc="/media/2612bbee-1ea0-43dd-82f4-c7e7d3fe634b_/eric/haskell/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-gcc" --with-ar="/usr/bin/ar" --with-ranlib="true" --with-alex="/usr/bin/alex" --with-happy="/usr/bin/happy" -- dist-install libraries/ghc-prim Configuring ghc-prim-0.3.0.0... ghc-cabal: /tmp/22147.o: does not exist make[1]: *** [libraries/ghc-prim/dist-install/package-data.mk] Error 1 make: *** [all] Error 2 I am not sure if I need to create a mk/build.mk file using the mk/build.mk.sample, but when I do so and add the line Stage1Only = YES I still get the same error only with a different temp filename.

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