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[GHC] #12122: User's guide (master): all links to libraries are broken
by GHC 28 May '16

28 May '16

#12122: User's guide (master): all links to libraries are broken -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Documentation | Version: 8.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Documentation Unknown/Multiple | bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Example. The page http://downloads.haskell.org/~ghc/master/users- guide/glasgow_exts.html#generic-programming has a broken link to GHC.Generics: http://downloads.haskell.org/~ghc/master/libraries/base-4.9.0.0/GHC- Generics.html. It should instead link to http://downloads.haskell.org/~ghc/master/libraries/html/base/GHC- Generics.html It seems all such links to libraries are broken. The content is also over a month old (20160411). Preferably, a resource called `master` would be automatically updated every day. If that's not possible, maybe it should just be removed, and people can compile their own version. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12122> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3021: A way to programmatically insert marks into heap profiling output
by GHC 28 May '16

28 May '16

#3021: A way to programmatically insert marks into heap profiling output -------------------------------------+------------------------------------- Reporter: SamB | Owner: Type: feature request | Status: new Priority: normal | Milestone: ⊥ Component: Profiling | Version: 6.10.1 Resolution: | Keywords: profiling Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #11094 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by thomie): * cc: bgamari (added) * related: => #11094 Comment: > in the long run profiling data should also go to the eventlog bgamari is working on that in #11094. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3021#comment:16> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9051: Report heap profile data in eventlog
by GHC 28 May '16

28 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] #11415: Pandoc fails to build on 4 GB machine
by GHC 27 May '16

27 May '16

#11415: Pandoc fails to build on 4 GB machine -------------------------------------+------------------------------------- Reporter: pavolzetor | Owner: Type: bug | Status: new Priority: normal | 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: -------------------------------------+------------------------------------- I made an attempt to install pandoc on laptop with 4 GB RAM and GHC was killed by OS after using all RAM and swap space (512 MB). Output from 'emerge pandoc' http://lpaste.net/148881 I can tolerate slow compile times, however this bug makes it impossible to build some packages which is worse. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11415> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11640: Panic because of "updateRole"
by GHC 27 May '16

27 May '16

#11640: Panic because of "updateRole" -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 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: -------------------------------------+------------------------------------- Not the most recent GHC {{{#!hs {-# LANGUAGE RankNTypes, TypeInType #-} import Data.Kind data HEq :: forall k1. k1 -> forall k2. k2 -> Type where }}} gives {{{ % ghci -ignore-dot-ghci tx9F.hs GHCi, version 8.1.20160117: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( tx9F.hs, interpreted ) ghc: panic! (the 'impossible' happened) (GHC version 8.1.20160117 for x86_64-unknown-linux): updateRole HEq k2_a115 [a114 :-> 0, a11e :-> 1, a11f :-> 2] Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug > }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11640> 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] #12120: GHC accepts invalid Haskell: `class Eq (a Int) => C a where`
by GHC 26 May '16

26 May '16

#12120: GHC accepts invalid Haskell: `class Eq (a Int) => C a where` -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: lowest | Milestone: Component: Compiler | Version: 8.0.1 Keywords: report-impact | Operating System: Unknown/Multiple Architecture: | Type of failure: Documentation Unknown/Multiple | bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- From the Haskell 2010 report [https://www.haskell.org/onlinereport/haskell2010/haskellch4.html chapter 4], * Class and instance declarations: {{{ | class [scontext =>] ... | instance [scontext =>] ... }}} * Normal type signatures: {{{ vars :: [context =>] ... }}} Notice the difference between `scontext` (//with// `s`) and `context` (without `s`). {{{ scontext → simpleclass | ( simpleclass1 , … , simpleclassn ) (n ≥ 0) simpleclass → qtycls tyvar }}} {{{ context → class | ( class1 , … , classn ) (n ≥ 0) class → qtycls tyvar | qtycls ( tyvar atype1 … atypen ) (n ≥ 1) }}} GHC seems to ignore this difference, and happily accepts `class Eq (a Int) => C a where`. Hugs (Version: September 2006) reports for that same example: {{{ Illegal Haskell 98 class constraint in class declaration *** Constraint : Eq (a Int) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12120> 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 26 May '16

26 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 26 May '16

26 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] #12016: Allow wildcards in type synonyms and data declarations
by GHC 26 May '16

26 May '16

#12016: Allow wildcards in type synonyms and data declarations -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: lowest | Milestone: Component: Compiler | Version: (Parser) | 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: -------------------------------------+------------------------------------- {{{#!hs data Konst a _ = Konst a type Const a _ = a type Tagged _ b = b type Forget m a _ = a -> m }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12016> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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