August 2015 - ghc-tickets

[GHC] #9034: GHCi panics when given C++ object file on GNU/Linux
by GHC 08 Jun '16

08 Jun '16

#9034: GHCi panics when given C++ object file on GNU/Linux ------------------------------------------+------------------------------- Reporter: jun0 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 7.8.2 Keywords: panic, dynamic linking | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: GHCi crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------------+------------------------------- When given a C++ object file, GHCi panics saying that it can't find standard C++ symbols the object file relies on. If foo.cc contains {{{#!C++ #include <iostream> extern "C" void foo () { std::cout << "bar"; } }}} and is compiled with {{{ g++ -fPIC -c -o foo.o foo.cc }}} then {{{ ghci foo.o -lstdc++ }}} fails with {{{ GHCi, version 7.8.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Loading object (static) foo.o ... ghc: panic! (the 'impossible' happened) (GHC version 7.8.2 for x86_64-unknown-linux): Loading temp shared object failed: /tmp/ghc14109_0/ghc14109_1.so: undefined symbol: _ZSt4cout Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} It makes no difference to add -L<C++ library paths> which was, IIRC, necessary in older versions of GHC. This applies to only GHCi with C++ -- GHC can link C++ object files just fine, while GHCi has no trouble loading C object files. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9034> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10565: GHC 7.10.2 RC: the impossible happened on hPDB-examples-1.2.0.2
by GHC 05 Jun '16

05 Jun '16

#10565: GHC 7.10.2 RC: the impossible happened on hPDB-examples-1.2.0.2 -----------------------------------------+--------------------------------- Reporter: snoyberg | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.10.2 Component: Compiler | Version: 7.10.2-rc1 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -----------------------------------------+--------------------------------- When compiling with the RC for Stackage, I get: {{{ [1 of 1] Compiling Main ( examples/Rg.hs, dist/build/Rg/Rg- tmp/Main.o ) <no location info>: ghc: panic! (the 'impossible' happened) (GHC version 7.10.1.20150619 for x86_64-unknown-linux): Simplifier ticks exhausted When trying UnfoldingDone bindIO To increase the limit, use -fsimpl-tick-factor=N (default 100) If you need to do this, let GHC HQ know, and what factor you needed To see detailed counts use -ddump-simpl-stats Total ticks: 19573 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10565> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9766: Use TypeLits in the meta-data encoding of GHC.Generics
by GHC 02 Jun '16

02 Jun '16

#9766: Use TypeLits in the meta-data encoding of GHC.Generics -------------------------------------+------------------------------------- Reporter: dreixel | Owner: dreixel Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: 9043 | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- This ticket serves to track the task of improving the meta-data representation in GHC.Generics as described in the following wiki page: https://ghc.haskell.org/trac/ghc/wiki/Commentary/Compiler/GenericDeriving#A… I'm working on this in branch `wip/GenericsMetaData`, and I intend to have it in 7.10. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9766> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9224: Add support for binary integer literals
by GHC 27 May '16

27 May '16

#9224: Add support for binary integer literals -------------------------------------------+------------------------------- Reporter: hvr | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler (Parser) | Version: Keywords: literals | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Easy (less than 1 hour) | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: -------------------------------------------+------------------------------- Currently, Haskell98/2010 support base-10, base-8 (via `0[oO]`-prefix) and base-16 (via `0[xX]`-prefix) integer literals. I hereby propose to add conditional support for base-2 integers via a `0[bB]`-prefix, controlled via a new `-XBinaryLiterals` language extension flag/pragma. The change to the lexer is trivial (see attached patch), however I'm stuck on the lexer using a 32-bit feature-mask, of which all 32bits are already taken, and I'd need a 33th bit for the `BinaryLiteralsBit` flag. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9224> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9051: Report heap profile data in eventlog
by GHC 27 May '16

27 May '16

#9051: Report heap profile data in eventlog ------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Profiling | Version: 7.9 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- It would be useful if heap profile data could be reported in the eventlog (either by assigning samples with IDs and recording the sample in the eventlog, or putting the entire profile information in the eventlog). This would make it easier to correlate heap profile data with other events reported by the RTS. It may be hard to stuff the entire sample in the eventlog because the sample is arbitrary size. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9051> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10604: Make Generic1 kind polymorphic
by GHC 27 May '16

27 May '16

#10604: Make Generic1 kind polymorphic -------------------------------------+------------------------------------- Reporter: | Owner: ekmett DerekElkins | Status: new Type: feature | Milestone: request | Version: 7.10.1 Priority: low | Operating System: Unknown/Multiple Component: Core | Type of failure: None/Unknown Libraries | Blocked By: Keywords: | Related Tickets: Architecture: | Unknown/Multiple | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- It looks to me that the Generic1 class (and the Rep1 associated type) can immediately be generalized to forall k. k -> *. If k was instantiated to anything other than *, you wouldn't be able to make an instance for Par1, but then I don't think it would ever come up so that would be exactly the right behavior. This allows, in particular, DataKinds to be used as a parameter to instances of Generic1. I don't know if this would affect deriving, but I wouldn't really expect it to. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10604> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9399: CPP does not process test case enum01.hs correctly
by GHC 25 May '16

25 May '16

#9399: CPP does not process test case enum01.hs correctly -------------------------------------+------------------------------------- Reporter: jrp | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Test Suite | Version: 7.8.3 Keywords: cpp | Operating System: MacOS X Architecture: x86_64 (amd64) | Type of failure: GHC Difficulty: Unknown | rejects valid program Blocked By: | Test Case: enum01.hs Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- The printTest cpp macro does not seem to be being applied in the test suite test enum01.hs (libraries/base) {{{ > ghci -cpp enum01.hs GHCi, version 7.8.3: 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 ( enum01.hs, interpreted ) enum01.hs:91:3: Not in scope: ‘printTest’ enum01.hs:92:3: Not in scope: ‘printTest’ : }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9399> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8914: Remove unnecessary constraints from MonadComprehensions and ParallelListComp
by GHC 25 May '16

25 May '16

#8914: Remove unnecessary constraints from MonadComprehensions and ParallelListComp -------------------------------------------+------------------------------- Reporter: Iceland_jack | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler (Type checker) | Version: Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Difficult (2-5 days) | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: -------------------------------------------+------------------------------- Many parts of MonadComprehensions don't actually require monads instance, the following could do with a `Functor` constraint {{{ fmapM :: Monad m => (a -> b) -> m a -> m b fmapM f xs = [ f x | x <- xs ] }}} and I don't see any reason why the class `MonadZip` (from [http://hackage.haskell.org/package/base-4.4.0.0/docs/Control-Monad- Zip.html Control.Monad.Zip]) requires a `Monad` constraint rather a `Functor` constraint: {{{ class Functor f => FunctorZip f where fzip :: f a -> f b -> f (a,b) fzip = fzipWith (,) fzipWith :: (a -> b -> c) -> f a -> f b -> f c fzipWith f fa fb = fmap (uncurry f) (fzip fa fb) funzip :: f (a,b) -> (f a, f b) funzip fab = (fmap fst fab, fmap snd fab) }}} with the laws {{{ fmap (f *** g) (fzip fa fb) = fzip (fmap f fa) (fmap g fb) fmap (const ()) fa = fmap (const ()) fb ==> funzip (fzip fa fb) = (fa, fb) }}} Same with `Applicative` (see ApplicativeDo): {{{ liftA2 :: Applicative f => (a -> b -> c) -> f a -> f b -> f c liftA2 f a1 a2 = [ f x1 x2 | x1 <- a1, x2 <- a2 ] }}} The reason I bring this up is because I'm writing a DSL that uses length- indexed vectors whose `Functor` and `FunctorZip` instances are trivial but whose `Monad` instance is [http://stackoverflow.com/questions/5802628 /monad-instance-of-a-number-parameterised-vector complicated] and not need. This proposal shares a similar rationale as ApplicativeDo. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8914> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9526: Add missing Generic instances in base
by GHC 25 May '16

25 May '16

#9526: Add missing Generic instances in base -------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: libraries/base | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Moderate (less | Type of failure: than a day) | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Most primitive types (`Int`, `Char`, etc.) have a GHC.Generics.Generic instance, but some are missing, such as `Integer` and the various `Word*` data types. We should consistently have instances for all primitive types offered by base, since they are required if you want to derive a Generic instance for any type that contains them. I boldly set the milestone to 7.10 because I naively assume this should be straightforward. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9526> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10512: Generic instances missing for Int32, Word64 etc.
by GHC 25 May '16

25 May '16

#10512: Generic instances missing for Int32, Word64 etc. -------------------------------------+------------------------------------- Reporter: | Owner: ekmett andreas.abel | Status: new Type: feature | Milestone: request | Version: 7.10.1 Priority: normal | Operating System: Unknown/Multiple Component: Core | Type of failure: None/Unknown Libraries | Blocked By: Keywords: | Related Tickets: Architecture: | Unknown/Multiple | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Some base types have Generic instances, like Integer, the machine-specific ones like Int32 have none. But these would be most useful when using generic Binary serialization. I think it makes sense to add Generic instances for *all* primitive types in base. I can define the instance myself, see https://github.com/agda/agda/commit/1d3710189989aced61be79c8e52945651fc94c0e {{{#!hs import GHC.Generics (Generic(..)) import qualified GHC.Generics as Gen data D_Int32 data C_Int32 instance Gen.Datatype D_Int32 where datatypeName _ = "Int32" moduleName _ = "GHC.Int32" -- packageName _ = "base" instance Gen.Constructor C_Int32 where conName _ = "" -- JPM: I'm not sure this is the right implementation... instance Generic Int32 where type Rep Int32 = Gen.D1 D_Int32 (Gen.C1 C_Int32 (Gen.S1 Gen.NoSelector (Gen.Rec0 Int32))) from x = Gen.M1 (Gen.M1 (Gen.M1 (Gen.K1 x))) to (Gen.M1 (Gen.M1 (Gen.M1 (Gen.K1 x)))) = x }}} However, as GHC.Generics is a moving target, and changes over the compiler versions, I'd rather not have to. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10512> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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