July 2014 - ghc-tickets

Re: [GHC] #7828: RebindableSyntax and Arrow
by GHC 02 Jul '14

02 Jul '14

#7828: RebindableSyntax and Arrow ----------------------------------------------+---------------------------- Reporter: AlessandroVermeulen | Owner: Type: bug | jstolarek Priority: normal | Status: new Component: Compiler (Type checker) | Milestone: 7.10.1 Resolution: | Version: 7.6.2 Operating System: Unknown/Multiple | Keywords: Type of failure: GHC rejects valid program | Architecture: Test Case: | Unknown/Multiple Blocking: | Difficulty: Unknown | Blocked By: | Related Tickets: #1537, | #3613 ----------------------------------------------+---------------------------- Comment (by ross): Replying to [comment:39 jstolarek]: > Replying to [comment:17 ross]: > > Here's a different suggestion for rebinding that is perhaps more analogous to the expression case. We could consider do and if commands as sugar for more primitive commands: > > {{{ > > do { rec { ss }; ss' } = > > do { vs <- (| fixA (\ ~vs -> do { ss; returnA -< vs })|); ss' } > > }}} > > Can the desugaring of `rec` be viewed as: > > {{{ > do { rec { ss }; ss' } = > (| fixA (\ ~vs -> do { ss; returnA -< vs })|) `bind` \ vs -> do { ss' } > }}} > > ? Yes, that's a combination of the above and the rule for `<-`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7828#comment:40> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1965: Allow unconstrained existential contexts in newtypes
by GHC 02 Jul '14

02 Jul '14

#1965: Allow unconstrained existential contexts in newtypes -------------------------------------+------------------------------------ Reporter: guest | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.6.2 Component: Compiler | Version: 6.8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by heisenbug): Replying to [comment:13 pumpkin]: > To be clear about what I'm looking for: > Yes, I always wondered how existentially quantifying over a type constructor with non-* domain kinds can ever necessitate extra information at runtime. I fully support the reopen proposal because of `data Hidden :: k -> * where Hide :: t a -> Hidden t` wants to be a `newtype`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1965#comment:14> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8993: Fold NullaryTypeClasses into MPTC
by GHC 01 Jul '14

01 Jul '14

#8993: Fold NullaryTypeClasses into MPTC ------------------------------------+------------------------------------- Reporter: owst | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- NullaryTypeClasses are an instance of MultiParamTypeClasses, so make it so. Suggested by Austin [http://www.reddit.com/r/haskell/comments/22lw1b/ghc_781_released/cgoi79c on reddit] -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8993> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8425: ghc-7.6.3: crossmodule inline leads to buggy code (-O2)
by GHC 01 Jul '14

01 Jul '14

#8425: ghc-7.6.3: crossmodule inline leads to buggy code (-O2) ----------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: x86_64 (amd64) | Type of failure: Runtime crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+------------------------------------- The bug is found as a crash of gf-3.4 ('Grammatical Framework') package compiled with -O2. With some debugging I've come to roughly following minimal example: This code compiles incorrectly: {{{ import BuggyOpt() -- bug inducer! import qualified Data.Map as Map import Data.Array.IArray {-# NOINLINE mkLin #-} mkLin :: Array Int (Array Int Int) -> Map.Map (Array Int Int) Int -> Int -> (Map.Map (Array Int Int) Int, Int) mkLin mseqs seqs seqid = let seq_ = mseqs ! seqid -- lookup/insert pair. exactly as in 'BuggyOpt' module in case Map.lookup seq_ seqs of Just seqid' -> (seqs,seqid') Nothing -> let seqid'' = Map.size seqs seqs' = Map.insert seq_ seqid'' seqs in (seqs',seqid'') }}} And this works fine: {{{ --import BuggyOpt() -- bug inducer! import qualified Data.Map as Map import Data.Array.IArray {-# NOINLINE mkLin #-} mkLin :: Array Int (Array Int Int) -> Map.Map (Array Int Int) Int -> Int -> (Map.Map (Array Int Int) Int, Int) mkLin mseqs seqs seqid = let seq_ = mseqs ! seqid -- lookup/insert pair. exactly as in 'BuggyOpt' module in case Map.lookup seq_ seqs of Just seqid' -> (seqs,seqid') Nothing -> let seqid'' = Map.size seqs seqs' = Map.insert seq_ seqid'' seqs in (seqs',seqid'') }}} Attached minimal test tarball and my results on it are: {{{ [("Project name","The Glorious Glasgow Haskell Compilation System") ,("GCC extra via C opts"," -fwrapv") ,("C compiler command","x86_64-pc-linux-gnu-gcc") ,("C compiler flags"," -fno-stack-protector -Wl,--hash-size=31 -Wl ,--reduce-memory-overheads") ,("ar command","/usr/bin/ar") ,("ar flags","q") ,("ar supports at file","YES") ,("touch command","touch") ,("dllwrap command","/bin/false") ,("windres command","/bin/false") ,("perl command","/usr/bin/perl") ,("target os","OSLinux") ,("target arch","ArchX86_64") ,("target word size","8") ,("target has GNU nonexec stack","True") ,("target has .ident directive","True") ,("target has subsections via symbols","False") ,("LLVM llc command","/usr/bin/llc") ,("LLVM opt command","/usr/bin/opt") ,("Project version","7.6.3") ,("Booter version","7.6.3") ,("Stage","2") ,("Build platform","x86_64-unknown-linux") ,("Host platform","x86_64-unknown-linux") ,("Target platform","x86_64-unknown-linux") ,("Have interpreter","YES") ,("Object splitting supported","YES") ,("Have native code generator","YES") ,("Support SMP","YES") ,("Unregisterised","NO") ,("Tables next to code","YES") ,("RTS ways","l debug thr thr_debug thr_l thr_p dyn debug_dyn thr_dyn thr_debug_dyn") ,("Leading underscore","NO") ,("Debug on","False") ,("LibDir","/usr/lib64/ghc-7.6.3") ,("Global Package DB","/usr/lib64/ghc-7.6.3/package.conf.d") ,("Gcc Linker flags","[\"-Wl,--hash-size=31\",\"-Wl,--reduce-memory- overheads\"]") ,("Ld Linker flags","[\"--hash-size=31\",\"--reduce-memory-overheads\"]") ] RUN good [1 of 2] Compiling Susp ( good/Susp.hs, good/Susp.o ) [2 of 2] Compiling Main ( good/main.hs, good/main.o ) Linking good/main ... (fromList [(array (0,0) [(0,42)],0)],0) RUN bad [1 of 3] Compiling BuggyOpt ( bad/BuggyOpt.hs, bad/BuggyOpt.o ) [2 of 3] Compiling Susp ( bad/Susp.hs, bad/Susp.o ) [3 of 3] Compiling Main ( bad/main.hs, bad/main.o ) Linking bad/main ... main: Error in array index; 0 not in range [0..0) TEST FAILED in bad }}} What we see here is the test with useless import mysteriously fails: > main: Error in array index; 0 not in range [0..0) while without import it works fine: > (fromList [(array (0,0) [(0,42)],0)],0) The functions in both BuggyOpt and Susp modules contain suspiciously similar code: {{{ case Map.lookup seq' seqs of Just id' -> (seqs,id') Nothing -> let last_seq = Map.size seqs in (Map.insert seq' last_seq seqs, last_seq) }}} But in BuggyOpt ghc somehow deduces some arguments and applies that effect to (unrelated, but looking similar) Susp module. Thanks! -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8425> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7828: RebindableSyntax and Arrow
by GHC 01 Jul '14

01 Jul '14

#7828: RebindableSyntax and Arrow ----------------------------------------------+---------------------------- Reporter: AlessandroVermeulen | Owner: Type: bug | jstolarek Priority: normal | Status: new Component: Compiler (Type checker) | Milestone: 7.10.1 Resolution: | Version: 7.6.2 Operating System: Unknown/Multiple | Keywords: Type of failure: GHC rejects valid program | Architecture: Test Case: | Unknown/Multiple Blocking: | Difficulty: Unknown | Blocked By: | Related Tickets: #1537, | #3613 ----------------------------------------------+---------------------------- Comment (by jstolarek): Replying to [comment:17 ross]: > Here's a different suggestion for rebinding that is perhaps more analogous to the expression case. We could consider do and if commands as sugar for more primitive commands: > {{{ > do { rec { ss }; ss' } = > do { vs <- (| fixA (\ ~vs -> do { ss; returnA -< vs })|); ss' } > }}} Can the desugaring of `rec` be viewed as: > {{{ > do { rec { ss }; ss' } = > (| fixA (\ ~vs -> do { ss; returnA -< vs })|) `bind` \ vs -> ss' } > }}} ? I'm working on this new desugaring now, but I'm unable to give any estimates of how long it might take. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7828#comment:39> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1965: Allow unconstrained existential contexts in newtypes
by GHC 30 Jun '14

30 Jun '14

#1965: Allow unconstrained existential contexts in newtypes -------------------------------------+------------------------------------ Reporter: guest | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.6.2 Component: Compiler | Version: 6.8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by pumpkin): To be clear about what I'm looking for: {{{ #!haskell data IntList where Nil :: IntList Cons :: Int -> IntList -> IntList data Nat = Z | S Nat data IntVec :: Nat -> * where NilV :: IntVec Z ConsV :: Int -> IntVec n -> IntVec (S n) -- N.B: not data newtype Exists (f :: k -> *) = forall x. Exists (f x) type IntVecList = Exists IntVec -- IntVec and IntVecList should be isomorphic! If Exists can't be a newtype, I have to pay a penalty for adding indices to my type :( }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1965#comment:13> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1965: Allow unconstrained existential contexts in newtypes
by GHC 30 Jun '14

30 Jun '14

#1965: Allow unconstrained existential contexts in newtypes -------------------------------------+------------------------------------ Reporter: guest | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.6.2 Component: Compiler | Version: 6.8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Changes (by jmcarthur): * cc: jake.mcarthur@… (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1965#comment:12> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1965: Allow unconstrained existential contexts in newtypes
by GHC 30 Jun '14

30 Jun '14

#1965: Allow unconstrained existential contexts in newtypes -------------------------------------+------------------------------------ Reporter: guest | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.6.2 Component: Compiler | Version: 6.8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by pumpkin): Just a minor bump on this. The more fancy GADT and Poly/DataKind programming I do, the more this bothers me. It seems like a real pity to be penalized (with an extra box) for choosing to encode invariants in indices, especially with all the new delicious features GHC has been getting recently. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1965#comment:11> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9145: hp2ps produces odd negative sawtooth
by GHC 30 Jun '14

30 Jun '14

#9145: hp2ps produces odd negative sawtooth --------------------------+------------------------------------------------ Reporter: | Owner: blackdog | Status: new Type: bug | Milestone: Priority: normal | Version: 7.8.2 Component: | Operating System: Linux Profiling | Type of failure: Incorrect result at runtime Keywords: | Test Case: Architecture: | Blocking: Unknown/Multiple | Difficulty: | Unknown | Blocked By: | Related Tickets: | --------------------------+------------------------------------------------ i'm profiling a process with about 22gb of usage before the OOMkiller gets it. the heap profile for it is very odd: -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9145> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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