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Re: [GHC] #989: Build GHC on Windows using Microsoft toolchain
by GHC 15 Oct '16

15 Oct '16

#989: Build GHC on Windows using Microsoft toolchain ------------------------------------+--------------------------- Reporter: simonmar | Owner: Type: feature request | Status: new Priority: low | Milestone: ⊥ Component: Compiler | Version: Resolution: | Keywords: Operating System: Windows | Architecture: x86 Type of failure: None/Unknown | Test Case: N/A Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | ------------------------------------+--------------------------- Changes (by RyanGlScott): * cc: RyanGlScott (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/989#comment:17> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9685: GHC fails to build with mingw32-make on Windows
by GHC 15 Oct '16

15 Oct '16

#9685: GHC fails to build with mingw32-make on Windows -------------------------------------+------------------------------------- Reporter: gintas | Owner: gintas Type: feature request | Status: new Priority: normal | Milestone: Component: Build System | Version: 7.9 Keywords: | Operating System: Windows Architecture: Unknown/Multiple | Type of failure: Difficulty: Unknown | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- It would be nice to be able to build ghc on Windows with mingw32-make which is bundled with the prebuilt gcc package that we are using for the ghc build. mingw32-make might be faster (due to less overhead associated with POSIX compatibility, forks etc.) and more reliable - msys2's make is a bit glitchy because it needs to fork off a lot of processes and sometimes runs into issues with fork(), which should not be a problem for mingw32-make. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9685> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10437: RunHaskell error in HSExtra on Win64
by GHC 15 Oct '16

15 Oct '16

#10437: RunHaskell error in HSExtra on Win64 -------------------------------------+------------------------------------- Reporter: | Owner: ScottSedgwick | Status: new Type: bug | Milestone: Priority: normal | Version: 7.8.3 Component: Compiler | Operating System: Windows Keywords: runhaskell | Type of failure: Compile-time Architecture: x86_64 | crash (amd64) | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- I ran the following command, and got this error: {{{ $ runhaskell shakefile.hs clean shakefile.hs: C:\Users\Scott Sedgwick\AppData\Roaming\cabal\x86_64 -windows-ghc-7.8.3\extra-1.2\HSextra-1.2.o: Not x86_64 PEi386 shakefile.hs: shakefile.hs: panic! (the 'impossible' happened) (GHC version 7.8.3 for x86_64-unknown-mingw32): loadObj "C:\\Users\\Scott Sedgwick\\AppData\\Roaming\\cabal\\x86_64-windows- ghc-7.8.3\\extra-1.2\\HSextra-1.2.o": failed Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} The shakefile in question looks like this: {{{ import Development.Shake import Development.Shake.FilePath --import System.Info srcFiles = [ "source/main.hs", "source/DBDataStructures.hs", "source/FormatDBData.hs", "source/GetDBData.hs", "source/ParseDBData.hs"] exeFile = "dist/build/mssql-er/mssql-er.exe" depFiles = [ "dependencies/erd/erd.exe", "dependencies/dot/Pathplan.dll", "dependencies/dot/config6", "dependencies/dot/gvc.dll", "dependencies/dot/iconv.dll", "dependencies/dot/libfontconfig-1.dll", "dependencies/dot/libgmodule-2.0-0.dll", "dependencies/dot/libpango-1.0-0.dll", "dependencies/dot/libpangowin32-1.0-0.dll", "dependencies/dot/ltdl.dll", "dependencies/dot/cdt.dll", "dependencies/dot/dot.exe", "dependencies/dot/gvplugin_dot_layout.dll", "dependencies/dot/libcairo-2.dll", "dependencies/dot/libfreetype-6.dll", "dependencies/dot/libgobject-2.0-0.dll", "dependencies/dot/libpangocairo-1.0-0.dll", "dependencies/dot/libpng14-14.dll", "dependencies/dot/zlib1.dll", "dependencies/dot/cgraph.dll", "dependencies/dot/freetype6.dll", "dependencies/dot/gvplugin_pango.dll", "dependencies/dot/libexpat.dll", "dependencies/dot/libglib-2.0-0.dll", "dependencies/dot/libgthread-2.0-0.dll", "dependencies/dot/libpangoft2-1.0-0.dll", "dependencies/dot/libxml2.dll"] copyDep :: FilePath -> Action() copyDep src = do let dst = "dist" </> (dropDirectory1 (dropDirectory1 src)) copyFile' src dst main :: IO() main = shakeArgs shakeOptions $ do want ["deploy"] "clean" ~> do cmd "cabal" "clean" "dist/setup-config" *> \_ -> do need ["mssql-er.cabal"] cmd "cabal" "configure" "--enable-tests" "configure" ~> do need ["dist/setup-config"] exeFile *> \_ -> do need (["configure"] ++ srcFiles) cmd "cabal" "build" "build" ~> do need [exeFile, "test"] "test" ~> do need srcFiles cmd "cabal" "test" "deploy" ~> do need ["build"] mapM_ copyDep depFiles }}} Strangely, if I compile that shakefile using ghc, then run it, it works correctly. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10437> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10122: PolyKinds: inferred type not as polymorphic as possible
by GHC 15 Oct '16

15 Oct '16

#10122: PolyKinds: inferred type not as polymorphic as possible -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1-rc2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- In the user's guide on [https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/kind- polymorphism.html kind polymorphism] the following example is presented: {{{#!hs f1 :: (forall a m. m a -> Int) -> Int -- f1 :: forall (k:BOX). -- (forall (a:k) (m:k->*). m a -> Int) -- -> Int }}} "Here in f1 there is no kind annotation mentioning the polymorphic kind variable, so k is generalised at the top level of the signature for f1, making the signature for f1 is as polymorphic as possible." When I ask GHCi for the type of `f1`, it is however not as polymorphic as possible: {{{ > :t f1 f1 :: (forall a (m :: * -> *). m a -> Int) -> Int }}} Trying to compile the following program: {{{#!hs {-# LANGUAGE PolyKinds #-} {-# LANGUAGE ExplicitForAll #-} {-# LANGUAGE Rank2Types #-} module PolyFail where f :: (forall a m. m a -> Int) -> Int f g = g (Just 3) }}} Results in this error: {{{ [1 of 1] Compiling PolyFail ( PolyFail.hs, PolyFail.o ) PolyFail.hs:8:10: Kind incompatibility when matching types: m0 :: k -> * Maybe :: * -> * Expected type: m0 a0 Actual type: Maybe a1 Relevant bindings include g :: forall (a :: k) (m :: k -> *). m a -> Int (bound at PolyFail.hs:8:3) f :: (forall (a :: k) (m :: k -> *). m a -> Int) -> Int (bound at PolyFail.hs:8:1) In the first argument of ‘g’, namely ‘(Just 3)’ In the expression: g (Just 3) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10122> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5927: A type-level "implies" constraint on Constraints
by GHC 15 Oct '16

15 Oct '16

#5927: A type-level "implies" constraint on Constraints -------------------------------------+------------------------------------- Reporter: illissius | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.4.1 checker) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Iceland_jack): [https://www.reddit.com/r/haskell/comments/52f77p/how_would_you_express_the_… This] has one of the best examples {{{#!hs type f ~> g = forall a. f a -> g a type f ~~> g = forall a b. f a b -> g a b newtype Free0 k p = Free0 (forall q. k q => (p -> q) -> q) newtype Free1 k p a = Free1 (forall q. k q => (p ~> q) -> q a) newtype Free2 k p a b = Free2 (forall q. k q => (p ~~> q) -> q a b) class Semigroup m class Semigroup m => Monoid m class Semigroupoid c class Semigroupoid c => Category c class Category c => Arrow c }}} you can define {{{#!hs instance p `Implies` Semigroup => Semigroup (Free0 p a) instance p `Implies` Monoid => Monoid (Free0 p a) instance p `Implies` Semigroupoid => Semigroupoid (Free2 p a) instance p `Implies` Category => Category (Free2 p a) instance p `Implies` Arrow => Arrow (Free2 p a) instance p `Implies` ArrowLoop => ArrowLoop (Free2 p a) -- (?) }}} instead of {{{#!hs instance Semigroup (Free0 Semigroup a) instance Semigroup (Free0 Monoid a) instance Monoid (Free0 Monoid a) instance Semigroupoid (Free2 Semigroupoid p) instance Semigroupoid (Free2 Category p) instance Semigroupoid (Free2 Arrow p) instance Semigroupoid (Free2 ArrowLoop p) instance Category (Free2 Category p) instance Category (Free2 Arrow p) instance Category (Free2 ArrowLoop p) instance Arrow (Free2 Arrow p) instance Arrow (Free2 ArrowLoop p) instance ArrowLoop (Free2 ArrowLoop p) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5927#comment:23> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5927: A type-level "implies" constraint on Constraints
by GHC 15 Oct '16

15 Oct '16

#5927: A type-level "implies" constraint on Constraints -------------------------------------+------------------------------------- Reporter: illissius | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.4.1 checker) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Iceland_jack): I believe `MonadTrans` should be {{{#!hs class forall m. Monad m `Implies` Monad (t m) => MonadTrans t where lift :: Monad m => m a -> (t m) a }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5927#comment:22> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12355: Invalid assembly in foreign prim
by GHC 15 Oct '16

15 Oct '16

#12355: Invalid assembly in foreign prim -------------------------------------+------------------------------------- Reporter: osa1 | 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: -------------------------------------+------------------------------------- {{{ ➜ prim_panic ghc Lib.hs [1 of 1] Compiling Lib ( Lib.hs, Lib.o ) /tmp/ghc14440_0/ghc_2.s: Assembler messages: /tmp/ghc14440_0/ghc_2.s:65:0: error: Error: number of operands mismatch for `jmp' `gcc' failed in phase `Assembler'. (Exit code: 1) ➜ prim_panic cat Lib.hs {-# LANGUAGE GHCForeignImportPrim, UnliftedFFITypes, MagicHash #-} module Lib where import GHC.Prim foreign import prim f1 :: Int# -> Int# }}} Tried with: HEAD as of today, 8.0.1. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12355> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12529: Error message: visible type application of constructor/variable that is not in scope
by GHC 15 Oct '16

15 Oct '16

#12529: Error message: visible type application of constructor/variable that is not in scope -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple TypeApplications | Architecture: | Type of failure: Incorrect Unknown/Multiple | warning at compile-time Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- If I use an identifier not in scope: {{{ $ ghci -ignore-dot-ghci GHCi, version 8.0.1: http://www.haskell.org/ghc/ :? for help Prelude> p <interactive>:1:1: error: Variable not in scope: p Prelude> P <interactive>:2:1: error: Data constructor not in scope: P }}} Using visible type application: {{{ $ ghci -ignore-dot-ghci -XTypeApplications GHCi, version 8.0.1: http://www.haskell.org/ghc/ :? for help Prelude> p @Int <interactive>:1:1: error: • Cannot apply expression of type ‘t0’ to a visible type argument ‘Int’ • In the expression: p @Int In an equation for ‘it’: it = p @Int Prelude> P @Int <interactive>:2:1: error: • Cannot apply expression of type ‘t0’ to a visible type argument ‘Int’ • In the expression: P @Int In an equation for ‘it’: it = P @Int }}} I would prefer these error messages to be the same as the first two: thoughts? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12529> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12696: Exception gives not enough information to be useful
by GHC 15 Oct '16

15 Oct '16

#12696: Exception gives not enough information to be useful -------------------------------------+------------------------------------- Reporter: flip101 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: exception | 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 was told in #haskell @freenode to report this as a bug. I have a program that throws exceptions and tried debugging the problem within ghci and also outside of ghci with these commands: {{{ stack build --ghc-options '-rtsopts -fprof-auto -fprof-auto-calls' --executable-profiling stack exec -- vhdl +RTS -xc }}} {{{#!hs tfComment :: Data from => from -> from tfComment = transformBi tf where tf (Comment ((pos_c, c), (pos_s, s))) = Comment $ ((pos_c, T.concat ["--", c]), (pos_s, s)) tf a = a zeroPos :: Data from => from -> from zeroPos = transformBi zp where zp sp@(M.SourcePos _ _ _) = sp { M.sourceName="", M.sourceLine=unsafePos 1, M.sourceColumn=unsafePos 1} zp x = x -- (a)dd (e)xtended(i)dentifier (s)laches aeis :: Data from => from -> from aeis = transformBi x where x (IExtended a) = let updated_text :: Text updated_text = T.concat ["\\", snd $ t_text a, "\\"] in IExtended $ a {t_text = (fst $ t_text a, updated_text)} x a = a bla = something.. where parser_prop :: ContextClause -> Bool parser_prop = \x -> (transformIn <$> Right x) == (transformOut <$> parseSource parser $ T.toStrict . printSource $ transformIn x) transformIn ast = zeroPos ast transformOut ast = tfComment $ aeis $ zeroPos ast }}} ghci trace {{{ λ> :trace main Stopped in <exception thrown>, <unknown> _exception :: e = _ λ> :back Logged breakpoint at Main.hs:95:13-26 _result :: from -> from tf :: Comment -> Comment λ> :list 94 tfComment :: Data from => from -> from 95 tfComment = transformBi tf -- transformBi tf highlighted here 96 where tf (Comment ((pos_c, c), (pos_s, s))) = Comment $ ((pos_c, T.concat ["--", c]), (pos_s, s)) λ> :back Logged breakpoint at Main.hs:242:28-57 _result :: from ast :: from λ> :list 241 transformIn ast = zeroPos ast 242 transformOut ast = tfComment $ aeis $ zeroPos ast -- tfComment $ aeis $ zeroPos ast highlighted here 243 λ> :force ast ast = Right [] λ> transformIn (Right []) Right [] λ> transformOut (Right []) Right [] λ> zeroPos (Right []) Right [] λ> aeis (Right []) Right [] λ> tfComment (Right []) Right [] }}} run with profiling options (this was aborted at some point) {{{ » stack exec -- vhdl +RTS -xc *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Data.CAF --> evaluated by: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2028_r3oe6 --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2028_r3oe6 *** Exception (reporting due to +RTS -xc): (THUNK_STATIC), stack trace: Data.Generics.Uniplate.Internal.Data.uniplateVerbose, called from Data.Generics.Uniplate.Internal.Data.CAF:uniplateVerbose --> evaluated by: Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2028_r3oe6 --> evaluated by: Data.Generics.Uniplate.Internal.Data.fromOracle, called from Data.Generics.Uniplate.Internal.Data.biplateData, called from Data.Generics.Uniplate.Data.biplate, called from Main.tfComment, called from Main.qcrp.transformOut, called from Main.qcrp.parser_prop, called from Main.qcrp.parser_prop, called from Main.qc2.logInput, called from Main.qc2.logInput, called from Main.qc2.logInput, called from Main.qc2, called from Test.QuickCheck.Property.forAllShrink.\.\, called from Test.QuickCheck.Property.property, called from Test.QuickCheck.Test.quickCheckWithResult.property', called from Test.QuickCheck.Test.quickCheckWithResult.\, called from Test.QuickCheck.Text.withNullTerminal, called from Test.QuickCheck.Test.quickCheckWithResult, called from Main.qc2, called from Main.qcrp, called from Main.ntc *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2025_r3oe3 --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2025_r3oe3 *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2022_r3oe0 --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl2022_r3oe0 *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.biplate.answer, called from Data.Generics.Uniplate.Data.biplate, called from Main.CAF:lvl1945_r3oc9 *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer6_r3ocg --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer6_r3ocg *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer7_r3ocp --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer7_r3ocp *** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: Data.Generics.Uniplate.Internal.Data.sybChildren.f, called from Data.Generics.Uniplate.Internal.Data.sybChildren, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f.cs, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate.f, called from Data.Generics.Uniplate.Internal.Data.insertHitMap.populate, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer8_r3ocy --> evaluated by: Data.HashMap.Base.toList', called from Data.HashMap.Base.equal, called from Data.HashMap.Base.==, called from Data.Generics.Uniplate.Internal.Data.fixEq, called from Data.Generics.Uniplate.Internal.Data.insertHitMap, called from Data.Generics.Uniplate.Internal.Data.readCacheFollower, called from Data.Generics.Uniplate.Data.descend.answer, called from Data.Generics.Uniplate.Data.descend, called from Data.Generics.Uniplate.Operations.transform.g, called from Data.Generics.Uniplate.Operations.transform, called from Main.CAF:answer8_r3ocy ^C^C^C^C }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12696> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12464: Add `instance Semigroup a => Semigroup (IO a)`
by GHC 14 Oct '16

14 Oct '16

#12464: Add `instance Semigroup a => Semigroup (IO a)` -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Core | Version: 8.0.1 Libraries | 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: -------------------------------------+------------------------------------- What the title says -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12464> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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