December 2015 - ghc-tickets

[GHC] #11276: GHC hangs/takes an exponential amount of time with simple program
by GHC 04 Feb '16

04 Feb '16

#11276: GHC hangs/takes an exponential amount of time with simple program -------------------------------------+------------------------------------- Reporter: mpickering | Owner: Type: bug | Status: new Priority: high | Milestone: Component: Compiler | Version: 7.10.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This was discovered when trying to compile xml-conduit. Here is the standalone test case with a few comments indicating how to make it compile. The program compiles with ghc-7.10.2 but fails with HEAD. {{{#!hs {-# LANGUAGE RankNTypes #-} module Hang where import Control.Monad import Data.Char data Event = EventBeginDocument | EventEndDocument | EventBeginDoctype | EventEndDoctype | EventInstruction | EventBeginElement | EventEndElement | EventContent Content | EventComment | EventCDATA data Content = ContentText String | ContentEntity String peek :: Monad m => Consumer a m (Maybe a) peek = undefined type Consumer i m r = forall o. ConduitM i o m r tag :: forall m a b c o . Monad m => ConduitM Event o m (Maybe c) tag = do _ <- dropWS return undefined where -- Add this and it works -- dropWS :: Monad m => ConduitM Event o m (Maybe Event) dropWS = do -- Swap these two lines and it works -- let x = undefined x <- peek let isWS = case x of -- Remove some of these and it works Just EventBeginDocument -> True Just EventEndDocument -> True Just EventBeginDoctype{} -> True Just EventEndDoctype -> True Just EventInstruction{} -> True Just EventBeginElement{} -> False Just EventEndElement{} -> False Just (EventContent (ContentText t)) | all isSpace t -> True | otherwise -> False Just (EventContent ContentEntity{}) -> False Just EventComment{} -> True Just EventCDATA{} -> False Nothing -> False if isWS then dropWS else return x -- Inlined Instances instance Functor (ConduitM i o m) where fmap f (ConduitM c) = ConduitM $ \rest -> c (rest . f) instance Applicative (ConduitM i o m) where pure x = ConduitM ($ x) {-# INLINE pure #-} (<*>) = ap {-# INLINE (<*>) #-} instance Monad (ConduitM i o m) where return = pure ConduitM f >>= g = ConduitM $ \h -> f $ \a -> unConduitM (g a) h instance Monad m => Functor (Pipe l i o u m) where fmap = liftM {-# INLINE fmap #-} instance Monad m => Applicative (Pipe l i o u m) where pure = Done {-# INLINE pure #-} (<*>) = ap {-# INLINE (<*>) #-} instance Monad m => Monad (Pipe l i o u m) where return = pure {-# INLINE return #-} HaveOutput p c o >>= fp = HaveOutput (p >>= fp) c o NeedInput p c >>= fp = NeedInput (p >=> fp) (c >=> fp) Done x >>= fp = fp x PipeM mp >>= fp = PipeM ((>>= fp) `liftM` mp) Leftover p i >>= fp = Leftover (p >>= fp) i newtype ConduitM i o m r = ConduitM { unConduitM :: forall b. (r -> Pipe i i o () m b) -> Pipe i i o () m b } data Pipe l i o u m r = HaveOutput (Pipe l i o u m r) (m ()) o | NeedInput (i -> Pipe l i o u m r) (u -> Pipe l i o u m r) | Done r | PipeM (m (Pipe l i o u m r)) | Leftover (Pipe l i o u m r) l }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11276> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10284: Create a dedicated `TypeError` exception type
by GHC 03 Feb '16

03 Feb '16

#10284: Create a dedicated `TypeError` exception type -------------------------------------+------------------------------------- Reporter: kosmikus | Owner: Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.10.1 Component: Compiler | Operating System: Unknown/Multiple Keywords: | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Ticket #10283 discusses using `-fdefer-type-errors` to test that certain programs do not type check. In practice, this involves evaluating certain expressions to WHNF at run- time can checking whether they trigger an exception. Currently, it seems the exception to catch is an `ErrorCall` exception. It would be nice if we could very specifically catch type errors though. It's entirely possible that a critical test case that I want to be a type error mistakenly type- checks and then calls `error`. In such a situation, it's hard to distinguish such a true run-time error from a deferred type error. It would be much nicer if something like `TypeError` would be thrown instead of `ErrorCall`. Yes, it's currently possible to look at the text of the `ErrorCall` and check for certain text fragments in there, but that sounds extremely fragile to me. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10284> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10345: Testsuite timeout_multiplier setting does not work as expected
by GHC 03 Feb '16

03 Feb '16

#10345: Testsuite timeout_multiplier setting does not work as expected -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Test Suite | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Other Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- I have a test case that - if failed - sends GHC into an infinite loop. The test case is small so I don't want to wait for default timeout (currently that's 5 minutes). The testsuite provides `timeout_multiplier` function to modify the default timeout but that setting seems to be ignored and the test is killed only after the default timeout time. I added my test to `all.T` file like this: {{{ test('tc265', timeout_multiplier(0.01), compile, ['']) }}} I also tried putting timeout setting into an array (`[timeout_multiplier(0.01)]`) but with no result. Merijn reports having same problems and bypassing them by writing a test that forks itself and kills the child process after a given timeout - see [[GhcFile(libraries/base/tests/T8089.hs)]]. I am adding a note on [[wiki:Building/RunningTests/Adding#Thesetupfield]] that this field does not work currently. Once this bug is fixed we need to remove that note. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10345> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8746: Crosscompiling
by GHC 03 Feb '16

03 Feb '16

#8746: Crosscompiling -------------------------------------+------------------------------------- Reporter: Visionstar | Owner: Type: bug | Status: new Priority: high | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc1 Keywords: Crosscompile | Operating System: Linux cross compile failed ncurses | Type of failure: Building GHC setupterm not found | failed Architecture: Unknown/Multiple | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | -------------------------------------+------------------------------------- Hello! I tried to crosscompile from linux i386 to arm-linux-gnueabihf, but i cant make it happen, because it gives me this weird error while running 'make': {{{ checking ncurses.h usability... yes checking ncurses.h presence... yes checking for ncurses.h... yes checking for setupterm in -ltinfo... no checking for setupterm in -lncursesw... no checking for setupterm in -lncurses... no checking for setupterm in -lcurses... no configure: error: in '/home/edi/ghc_cross/ghc/libraries/terminfo': configure: error: curses library not found, so this package cannot be built See 'config.log' for more details make[2]: *** [libraries/terminfo/dist-install/package-data.mk] Error 1 make[1]: *** [all_libraries/terminfo] Error 2 make[1]: Leave Directory '/home/edi/ghc_cross/ghc' make: *** [all] Error 2 }}} What have i done: -) Compiled 7.8.0 from github (The log says 'That should have been 7.8.0', i chose 7.8 because i thought it would be more stable for crosscompiling) to my i386 (normal boot, configure, make, make install). This worked fine -) installed newest llvm from svn (LLVM version 3.5svn) -) replaced the libffi-3.0.11.tar.gz in ghc/libffi-tarballs with libffi-3.0.13 -) added this version of mk/build.mk: {{{ SRC_HC_OPTS = -H32m _o -fasm -Rghc-timing GhcStage1HcOpts = -O -fasm GhcStage2HcOpts = -O0 -DDEBUG -Wall GhcLibHcOpts = -O -fasm -XGenerics GhcLibWays = v dyn SplitObjs = NO Stage1Only = YES }}} -) downloaded the sourcecode of ncurses from http://ftp.de.debian.org/debian/pool/main/n/ncurses/ncurses_5.9.orig.tar.gz and builded it with "./configure arm-linux-gnueabihf --with-gcc=arm-linux- gnueabihf-gcc --target=arm-linux-gnueabihf --prefix=/usr/arm-linux- gnueabihf " + "make". afterwards i added the folder to my $PATH -)did "perl boot", "./configure --target=arm-linux-gnueabihf --with-gcc =arm-linux-gnueabihf-gcc --prefix=/usr/arm-linux-gnueabihf" and "make". ./configure worked, but make gives me this weird error. I also tried copying all included files from ncurses to the libraries/terminfo folder, but that also didn't work. I think the mistake is somewhere in the building process, but i'm not exactly sure, so thats why i'm posting this bug. Does anyone have an idea about that? PS: i also made sure that i met the prerequirements mentioned in https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Linux and https://ghc.haskell.org/trac/ghc/wiki/Building/CrossCompiling Greetings, Edi -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8746> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11247: Weird error from running runghc on an invalid input filename
by GHC 02 Feb '16

02 Feb '16

#11247: Weird error from running runghc on an invalid input filename -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.4 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #7765 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I had files `random.hs` and `random.hi` and `random.o`, so I accidentally entered the following command with tab completion. {{{ rwbarton@morphism:/tmp$ runghc random. Warning: ignoring unrecognised input `random.' random.:1:33: Not in scope: ‘main’ Perhaps you meant ‘min’ (imported from Prelude) }}} #7765 is surely related, but with HEAD (well, rather old, but at least new enough to contain the fix for #7765), the error is not really any better: {{{ rwbarton@morphism:/tmp$ ~/ghc/inplace/bin/runghc random. Warning: ignoring unrecognised input `random.' random.:0:53: error: Variable not in scope: main :: IO a0 Perhaps you meant ‘min’ (imported from Prelude) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11247> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11100: Remote GHCi
by GHC 02 Feb '16

02 Feb '16

#11100: Remote GHCi -------------------------------------+------------------------------------- Reporter: simonmar | Owner: simonmar Type: task | Status: new Priority: normal | Milestone: 8.0.1 Component: GHCi | Version: 7.10.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This task is to implement Remote GHCi, i.e. running interpreted code in a separate process. For more details see [wiki:RemoteGHCi]. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11100> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11082: Tweak workflow around overlong lines
by GHC 30 Jan '16

30 Jan '16

#11082: Tweak workflow around overlong lines -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Build System | Version: 7.10.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- [https://mail.haskell.org/pipermail/ghc-devs/2015-November/010373.html This thread] discussed potential changes to the way the GHC dev workflow deals with overlong lines. This ticket summarizes the discussion. '''Initial complaint:''' arc/Phab is too heavy-handed about overlong lines. Almost all patchers have to write a vacuous "explanation" for them, and the overlong line warnings clutter code reviews. '''Initial suggestion:''' After `arc diff` is run, it will count the number of overlong lines before and after the patch. If there are more after, have the last thing `arc diff` outputs be a stern telling-off of the dev, along the lines of {{{ Before your patch, 15 of the edited lines were over 80 characters. Now, a whopping 28 of them are. Can't you do better? Please? }}} '''Reactions:''' * +1 * Even the delta in overlong lines is bad, because perhaps a small refactor added to the length of an identifier. * We might just want to reject code with overlong lines. Then the problem would really go away. It favors one-time work over many-time maintenance burden. (Austin's point, +1 by Alexander Berntsen) * This would cause more work and would increase the barrier to contribution. And sometimes it's appropriate/more readable to have overlong lines. * 80 is too small. 120 (SPJ)? 132 (Ed Kmett)? * And a small limit discourages informative identifiers. * Just drop the column limit entirely. * Why 80? Because two 80-column buffers fit nicely side-by-side on small laptop screens. Three such columns fit nicely on monitors. Several (4 emails) echoed this point. Bottom line: no one expressed liking the status quo (though Simon M called it "not terrible"). If we're to choose a limit, a choice of 80 seemed to appease the plurality of respondents. Two respondents advocate enforcing the limit. I count four respondents rejecting hard enforcement. In my (surely biased) view, this means that we should implement my original proposal. :) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11082> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10310: MakingReleases outdated or build system problems
by GHC 30 Jan '16

30 Jan '16

#10310: MakingReleases outdated or build system problems -------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Build | Version: 7.10.1 System | Operating System: Unknown/Multiple Keywords: | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Hey, I have some problems following https://ghc.haskell.org/trac/ghc/wiki/MakingReleases with HEAD. I'll collect them here, maybe we can update the Wiki page together, or fix the corresponding problems in the build system if they are problems. 1) `make sdist` fails with the problem that `ghc-tarballs` doesn't exist. I've heard that's only needed on Windows, and that some people seem to get it by cloning a submodule when they are on Windows. A `mkdir ghc-tarballs` fixed it. Maybe that directory should be created by the build system? 2) When I `make` in the unpacked sdist tarball, I get {{{ "" -P 'filename.as.url=0' utils/haddock/doc/haddock.xml --ps -o utils/haddock/doc/haddock.ps "" -P 'filename.as.url=0' utils/haddock/doc/haddock.xml --pdf -o utils/haddock/doc/haddock.pdf /bin/bash: : command not found /bin/bash: : command not found make[1]: *** [utils/haddock/doc/haddock.ps] Error 127 make[1]: *** Waiting for unfinished jobs.... make[1]: *** [utils/haddock/doc/haddock.pdf] Error 127 }}} Looks like some program was set to the empty string here. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10310> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11005: GHC's build system can't deal with ghc install path with multiple spaces in it
by GHC 30 Jan '16

30 Jan '16

#11005: GHC's build system can't deal with ghc install path with multiple spaces in it -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: lowest | Milestone: ⊥ Component: Build System | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Building GHC Unknown/Multiple | failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Essentially, there are a bunch of places in the build system where we forget to quote paths, and so the spaces collapse into a single space and the paths fail. I fixed a few low hanging instances of this but I got hsc2hs to fail: {{{ "inplace/bin/hsc2hs" '--cc=/bin/gcc' '--ld=/bin/gcc' --cross-safe --cflag=-Wall --cflag=-fno-stack-protector --cflag=-Dx86_64_HOST_ARCH=1 --cflag=-Dlinux_HOST_OS=1 --cflag=-D__GLASGOW_HASKELL__=711 '--cflag=-fno- stack-protector' '--cflag=-Wall' '--cflag=-Icompiler/stage1/build/autogen' '--cflag=-Icompiler/.' '--cflag=-Icompiler/parser' '-- cflag=-Icompiler/utils' '--cflag=-Icompiler/stage1' '-- cflag=-I/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/process-1.2.3.0/include' '-- cflag=-I/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/directory-1.2.2.0/include' '-- cflag=-I/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/unix-2.7.1.0/include' '-- cflag=-I/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/time-1.5.0.1/include' '-- cflag=-I/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/bytestring-0.10.6.0/include' '-- cflag=-I/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/base-4.8.2.0/include' '-- cflag=-I/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/integer-gmp-1.0.0.0/include' '-- cflag=-I/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/include' '--cflag=-Werror=unused-but-set- variable' '--cflag=-Wno-error=inline' '--lflag=-L/home/hs01/ezyang/ghc- bootstrap/libraries/transformers/dist-boot/build' '-- lflag=-L/home/hs01/ezyang/ghc-bootstrap/libraries/template-haskell/dist- boot/build' '--lflag=-L/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/process-1.2.3.0' '--lflag=-L/home/hs01/ezyang /ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/pretty-1.1.2.0' '--lflag=-L/home/hs01/ezyang /ghc-bootstrap/libraries/hpc/dist-boot/build' '--lflag=-L/home/hs01/ezyang /ghc-bootstrap/libraries/hoopl/dist-boot/build' '-- lflag=-L/home/hs01/ezyang/ghc-bootstrap/libraries/ghc-boot/dist- boot/build' '--lflag=-L/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/directory-1.2.2.0' '--lflag=-L/home/hs01/ezyang /ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/unix-2.7.1.0' '--lflag=-L/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/time-1.5.0.1' '--lflag=-L/home/hs01/ezyang/ghc- validate/bindisttest/install dir/lib/ghc-7.11.20151022/filepath-1.4.0.0' ' --lflag=-L/home/hs01/ezyang/ghc-bootstrap/libraries/binary/dist- boot/build' '--lflag=-L/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/containers-0.5.6.2' '--lflag=-L/home/hs01/ezyang /ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/bytestring-0.10.6.0' '-- lflag=-L/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/deepseq-1.4.1.1' '--lflag=-L/home/hs01/ezyang /ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/array-0.5.1.0' '--lflag=-L/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/base-4.8.2.0' '--lflag=-L/home/hs01/ezyang/ghc- validate/bindisttest/install dir/lib/ghc-7.11.20151022/integer- gmp-1.0.0.0' '--lflag=-L/home/hs01/ezyang/ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/ghc-prim-0.4.0.0' '--lflag=-L/home/hs01/ezyang /ghc-validate/bindisttest/install dir/lib/ghc-7.11.20151022/rts' '-- lflag=-lrt' '--lflag=-lutil' '--lflag=-ldl' '--lflag=-lpthread' '-- lflag=-lgmp' '--lflag=-lm' '--lflag=-lrt' '--lflag=-ldl' '--lflag=-lelf' ' --lflag=-ldw' --cflag=-Icompiler/stage1/build/autogen --cflag=-include --cflag=compiler/stage1/build/autogen/cabal_macros.h compiler/utils/Fingerprint.hsc -o compiler/stage1/build/Fingerprint.hs }}} Notice that there is only a single space in the `include` path passed to hsc2hs. I didn't feel like tracking down where we didn't quote enough. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11005> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10707: -fth-dec-file outputs invalid case clauses
by GHC 29 Jan '16

29 Jan '16

#10707: -fth-dec-file outputs invalid case clauses -------------------------------------+------------------------------------- Reporter: Fabian | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Other Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #10701 Differential Revisions: | -------------------------------------+------------------------------------- instance Data.Aeson.Types.Class.ToJSON Language.Haskell.TH.Syntax.Name where Data.Aeson.Types.Class.toJSON x = \ k_a94l v_a94m -> case k_a94l of { GHC.Base.Just "" -> GHC.Err.undefined GHC.Base.Nothing -> GHC.Err.undefined } (GHC.Base.Just "test") "test2" -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10707> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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