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[GHC] #8959: GHCi should honour UnicodeSyntax
by GHC 19 Dec '18

19 Dec '18

#8959: GHCi should honour UnicodeSyntax -------------------------------------------+------------------------------- Reporter: Fuuzetsu | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | 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: -------------------------------------------+------------------------------- When we load a module into GHCi with -XUnicodeSyntax, GHCi should default to printing information with the relevant unicode symbols. {{{ *Communication> let a ∷ Int; a = 7 *Communication> :t a a :: Int }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8959> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16050: Instance resolution error message unclear, because of missing kind information
by GHC 19 Dec '18

19 Dec '18

#16050: Instance resolution error message unclear, because of missing kind information -------------------------------------+------------------------------------- Reporter: chessai | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 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: -------------------------------------+------------------------------------- consider the following modules: {{{#!hs module A where (.) :: forall (a :: TYPE 'UnliftedRep) (b :: TYPE 'UnliftedRep) (c :: TYPE 'UnliftedRep). (b -> c) -> (a -> b) -> (a -> c) (.) f g = \x -> f (g x) data UList (a :: TYPE 'UnliftedRep) where UNil :: UList a UCons :: a -> UList a -> UList a mapFB :: forall (a :: TYPE 'UnliftedRep) (elt :: TYPE 'UnliftedRep) (lst :: Type). (elt -> lst -> lst) -> (a -> elt) -> a -> lst -> lst mapFB c f = \x ys -> c (f x) ys {-# RULES "mapFB" forall c f g. mapFB (mapFB c f) g = mapFB c (f . g) #-} }}} {{{#!hs module B where import Control.Category ((.)) data UList (a :: TYPE 'UnliftedRep) where UNil :: UList a UCons :: a -> UList a -> UList a mapFB :: forall (a :: TYPE 'UnliftedRep) (elt :: TYPE 'UnliftedRep) (lst :: Type). (elt -> lst -> lst) -> (a -> elt) -> a -> lst -> lst mapFB c f = \x ys -> c (f x) ys {-# RULES "mapFB" forall c f g. mapFB (mapFB c f) g = mapFB c (f . g) #-} }}} Module 'A' works fine. Module 'B', fails with the following error: {{{#!hs • No instance for (Category (->)) arising from a use of ‘.’ • In the second argument of ‘mapFB’, namely ‘(f . g)’ In the expression: mapFB c (f . g) When checking the transformation rule "mapFB" | line| "mapFB" forall c f g. mapFB (mapFB c f) g = mapFB c (f . g) | ^^^ }}} I expected this failure because of the kind mismatch; the category instance for `(->)` obviously requires that it be kinded `Type -> Type -> Type`. However, it confused someone I am teaching, who said to me that they didn't understand the error, since they expected it to work as `(->)` does indeed have a Category instance. (They are very unfamiliar with Levity-Polymorphism). My question is this: Would it be preferable to include such kind information in the error message? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16050> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16068: Unsaturated type synonyms as arguments work in 8.6.3 but not HEAD
by GHC 19 Dec '18

19 Dec '18

#16068: Unsaturated type synonyms as arguments work in 8.6.3 but not HEAD -------------------------------------+------------------------------------- Reporter: | Owner: (none) quasicomputational | Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.7 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: -------------------------------------+------------------------------------- Input, derived from code seen in the wild in hpack 0.31.1: {{{ {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE RankNTypes #-} {-# LANGUAGE FlexibleContexts #-} module Main where type WithCommonOptions cSources cxxSources jsSources a = a data Traverse m cSources cSources_ cxxSources cxxSources_ jsSources jsSources_ = Traverse { traverseCSources :: cSources -> m cSources_ , traverseCxxSources :: cxxSources -> m cxxSources_ , traverseJsSources :: jsSources -> m jsSources_ } type Traversal_ t = forall m cSources cSources_ cxxSources cxxSources_ jsSources jsSources_ a. Monad m => Traverse m cSources cSources_ cxxSources cxxSources_ jsSources jsSources_ -> t cSources cxxSources jsSources a -> m (t cSources_ cxxSources_ jsSources_ a) traverseWithCommonOptions :: Traversal_ WithCommonOptions traverseWithCommonOptions = undefined main = return () }}} Using a GHC compiled from revision 074eae255793de6a94e8172015e7022c80a5cd15, I get this error: {{{ Main.hs:19:30: error: • The type synonym ‘WithCommonOptions’ should have 4 arguments, but has been given none • In the type signature: traverseWithCommonOptions :: Traversal_ WithCommonOptions | 19 | traverseWithCommonOptions :: Traversal_ WithCommonOptions | }}} GHC 8.6.3 accepts the module without complaint. I'm actually surprised that the previous code worked and I wouldn't complain if this is closed as working as intended. However, there's no mention of this change in the migration guide for 8.8 yet, so I'm not certain it's intentional. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16068> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15503: interpreter: sequence_ (replicate 100000000 (return ())) gobbles up memory
by GHC 19 Dec '18

19 Dec '18

#15503: interpreter: sequence_ (replicate 100000000 (return ())) gobbles up memory -------------------------------------+------------------------------------- Reporter: int-e | Owner: (none) Type: bug | Status: new Priority: low | Milestone: 8.6.1 Component: GHCi | Version: 8.4.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Runtime Unknown/Multiple | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I consider this to be more of a curiosity than a bug, but it might still be worth investigating. The following line, {{{#!hs sequence_ (replicate 100000000 (return ())) }}} causes `ghci` to grow quite big (here it's 6GB on 64 bit Linux; it's roughly proportional to the `100000000` number). This used to be better in ancient times--before version 8.0.1, ghci ran this code in what looks like constant memory. (This came up indirectly on #haskell; somebody had adapted Hutton's game of life program, http://www.cs.nott.ac.uk/~gmh/life.lhs which uses busy waiting for a delay.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15503> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16011: GHCi leaks memory even with -fno-it.
by GHC 19 Dec '18

19 Dec '18

#16011: GHCi leaks memory even with -fno-it. -------------------------------------+------------------------------------- Reporter: AndreasK | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.3 Component: GHCi | Version: 8.7 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: -------------------------------------+------------------------------------- GHCi leaks are not exactly new, but this one is especially easy to trigger/reproduce. The memory allocated by f never gets freed. {{{ PS E:\binary-perf> ..\ghc-8.6.1\bin\ghci.exe -fno-it GHCi, version 8.6.1: http://www.haskell.org/ghc/ :? for help Prelude> f = [1 .. 20000000] :: [Int] Prelude> length f 20000000 Prelude> f = [1 .. 20000001] :: [Int] Prelude> length f 20000001 Prelude> f = [1 .. 20000002] :: [Int] Prelude> length f 20000002 Prelude> f = [1 .. 20000000] :: [Int] Prelude> length f 20000000 Prelude> }}} Or using head and even simpler: {{{ PS E:\binary-perf> ..\ghc_commonAsm\inplace\bin\ghci.exe -fno-it GHCi, version 8.7.20181207: http://www.haskell.org/ghc/ :? for help Loaded package environment from E:\binary- perf\.ghc.environment.x86_64-mingw32-8.7.20181207 Prelude> f = replicate 2000000 False Prelude> length f 2000000 Prelude> f = replicate 2000000 False Prelude> length f 2000000 Prelude> f = replicate 2000000 False Prelude> length f 2000000 Prelude> f = replicate 2000000 False Prelude> length f }}} GHC just keeps using more and more memory when I repeat this. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16011> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15979: Core Lint error with LiberalTypeSynonyms
by GHC 18 Dec '18

18 Dec '18

#15979: Core Lint error with LiberalTypeSynonyms -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.8.1 Component: Compiler | Version: 8.6.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# LANGUAGE DataKinds #-} {-# LANGUAGE LiberalTypeSynonyms #-} {-# LANGUAGE PolyKinds #-} {-# OPTIONS_GHC -dcore-lint #-} module Bug where import Data.Kind type KindOf (a :: k) = k wat :: KindOf (forall (a :: ()). a) wat = () }}} {{{ $ /opt/ghc/8.6.2/bin/ghc Bug.hs [1 of 1] Compiling Bug ( Bug.hs, Bug.o ) *** Core Lint errors : in result of Desugar (before optimization) *** <no location info>: warning: In the type ‘KindOf (forall (a :: ()). a)’ Non-*-like kind when *-like expected: () when checking the body of forall: forall (a :: ()). a *** Offending Program *** Rec { $trModule :: Module [LclIdX] $trModule = Module (TrNameS "main"#) (TrNameS "Bug"#) wat :: KindOf (forall (a :: ()). a) [LclIdX] wat = () end Rec } *** End of Offense *** <no location info>: error: Compilation had errors }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15979> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16067: Profiled GHCi segfaults under Windows.
by GHC 18 Dec '18

18 Dec '18

#16067: Profiled GHCi segfaults under Windows. ----------------------------------------+------------------------------- Reporter: AndreasK | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 8.7 Keywords: | Operating System: Windows Architecture: Unknown/Multiple | Type of failure: GHCi crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+------------------------------- Building ghc with the prof flavour and trying to run ghci segfaults on master. {{{ C:\ghc\msys64\home\Andi\ghc_head\inplace\bin\ghc-stage2.exe --interactive GHCi, version 8.7.20181218: https://www.haskell.org/ghc/ :? for help Access violation in generated code when reading 0xffffffffffffffff Attempting to reconstruct a stack trace... Frame Code address * 0x67cd990 0x4d6634c C:\ghc\msys64\home\Andi\ghc_head\inplace\bin \ghc-stage2.exe+0x496634c * 0x67cd9f0 0x4d51848 C:\ghc\msys64\home\Andi\ghc_head\inplace\bin \ghc-stage2.exe+0x4951848 * 0x67cda50 0x4d5192f C:\ghc\msys64\home\Andi\ghc_head\inplace\bin \ghc-stage2.exe+0x495192f * 0x67cda80 0x4d678a1 C:\ghc\msys64\home\Andi\ghc_head\inplace\bin \ghc-stage2.exe+0x49678a1 * 0x67cda88 0x4c5fe64 C:\ghc\msys64\home\Andi\ghc_head\inplace\bin \ghc-stage2.exe+0x485fe64 * 0x67cda90 0x1083d0 * 0x67cda98 0x88e5020 * 0x67cdaa0 0x88e36a1 * 0x67cdaa8 0x2000000 C:\ghc\msys64\home\Andi\ghc_head\inplace\bin \ghc-stage2.exe+0x1c00000 }}} Just starting it in gdb tells me this is happening in registerCcsList in the RTS. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16067> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15681: Take {-# COMPLETE #-} pragma into consideration when using MonadFailDesugaring
by GHC 18 Dec '18

18 Dec '18

#15681: Take {-# COMPLETE #-} pragma into consideration when using MonadFailDesugaring -------------------------------------+------------------------------------- Reporter: chshersh | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.6.1 Keywords: pattern- | Operating System: Unknown/Multiple matching,monadfail,desugaring | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Consider the following code: {{{#!hs import Data.List.NonEmpty (NonEmpty (..)) foo :: Monad m => m (NonEmpty a) -> m a foo m = do (x :| _) <- m pure x }}} It works completely fine on GHC 8.6.1 and doesn't require `MonadFail` constraint because `NonEmpty` has only single constructor so there're no other cases in pattern-matching. Howewer, if I rewrite this code using `-XPatternSynonyms` with `{-# COMPLETE #-}` pragma, it doesn't work anymore. {{{#!hs {-# LANGUAGE PatternSynonyms #-} import Data.List.NonEmpty (NonEmpty (..)) newtype Foo a = Foo (NonEmpty a) pattern (:||) :: a -> [a] -> Foo a pattern x :|| xs <- Foo (x :| xs) {-# COMPLETE (:||) #-} foo :: Monad m => m (Foo a) -> m a foo m = do (x :|| _) <- m pure x }}} And I see the following error: {{{ • Could not deduce (Control.Monad.Fail.MonadFail m) arising from a do statement with the failable pattern ‘(x :|| _)’ from the context: MonadFoo m bound by the type signature for: foo :: forall (m :: * -> *) a. MonadFoo m => m (Foo a) -> m a at /Users/fenx/haskell/sandbox/Fail.hs:13:1-37 Possible fix: add (Control.Monad.Fail.MonadFail m) to the context of the type signature for: foo :: forall (m :: * -> *) a. MonadFoo m => m (Foo a) -> m a • In a stmt of a 'do' block: (x :|| _) <- m In the expression: do (x :|| _) <- m pure x In an equation for ‘foo’: foo m = do (x :|| _) <- m pure x | 15 | (x :|| _) <- m | ^^^^^^^^^^^^^^ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15681> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15808: Master sefaults on windows during aeson build when stage2 libs have dwarf enabled.
by GHC 18 Dec '18

18 Dec '18

#15808: Master sefaults on windows during aeson build when stage2 libs have dwarf enabled. -------------------------------------+------------------------------------- Reporter: AndreasK | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.7 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 haven't had any luck with reproducing it outside of building the aeson package with cabal yet. So for now just documenting the fact. build.mk used {{{ GhcLibHcOpts += -g3 GhcRtsHcOpts += -g3 STRIP_CMD = : BUILD_PROF_LIBS = NO SplitObjs = NO SplitSections = NO HADDOCK_DOCS = NO BUILD_SPHINX_HTML = NO BUILD_SPHINX_PDF = NO BUILD_MAN = NO }}} Error log: {{{ "E:/ghc_dwarf/inplace/bin/ghc-stage2.exe" "--make" "-fbuilding-cabal- package" "-O" "-outputdir" "C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build" "-odir" "C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build" "-hidir" "C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build" "-stubdir" "C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build""-i" "-iC:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build" "-i." "-iattoparsec-iso8601/" "-ipure" "-iC:\ghc\msys64\home\Andi\aeson_repro \dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\autogen" "-iC:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\global- autogen" "-IC:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\autogen" "-IC:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\global- autogen" "-IC:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build" "-Iinclude" "-IC:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\include" "-optP-include" "-optPC:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\autogen\cabal_macros.h" "-this-unit-id" "aeson-1.4.1.0-inplace" "-hide-all-packages" "-Wmissing- home-modules" "-no-user-package-db" "-package-db" "C:\Users\Andi\AppData\Roaming\cabal\store\ghc-8.7.20181025\package.db" "-package-db" "C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\packagedb\ghc-8.7.20181025" "-package-db" "C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\package.conf.inplace" "-package-id" "attoparsec-0.13.2.2-8913a968506e9e83757f6fe696d6fe61e0d4b4a8" "-package- id" "base-4.12.0.0" "-package-id" "base- compat-0.10.5-34e11ceb2d98e0262d1d958bca2afc3184e70c60" "-package-id" "bytestring-0.10.8.2" "-package-id" "containers-0.6.0.1" "-package-id" "deepseq-1.4.4.0" "-package-id" "dlist-0.8.0.5-681a0f929505417757ba9f9981a50ab1d7c8a0e0" "-package-id" "ghc-prim-0.5.3" "-package-id" "hashable-1.2.7.0-50f89c5dee92df34fc2d6540cfde1983f26d8e31" "-package-id" "primitive-0.6.4.0-c08c185073660c1604acdddfe5c369afae583ba2" "-package-id" "scientific-0.3.6.2-4bea197b4523e02da61c34a1eed01432d9fefff6" "-package- id" "tagged-0.8.6-d3cce1acba663b646f565adb64d80579664d8caa" "-package-id" "template-haskell-2.14.0.0" "-package-id" "text-1.2.3.1" "-package-id" "th-abstraction-0.2.8.0-e197ba78a6de8bf8fc5d00ecb5a358a8b27bcc92" "-package-id" "time-1.8.0.2" "-package-id" "time-locale- c_-0.1.1.5-7549537073e62ce01921c89c30cc6cafeed99b5b" "-package-id" "unordered-con_-0.2.9.0-f5cd33176070f516c88b1aac3ef61959b09fcfa6" "-package-id" "uuid-types-1.0.3-f68643250767dce83d2c227104d15a0aa9c3c77f" "-package-id" "vector-0.12.0.1-3a9a26f81a463f0efefa41528af3e27d3a88cc7d" "-XHaskell2010" "Data.Aeson" "Data.Aeson.Encoding" "Data.Aeson.Parser" "Data.Aeson.Text" "Data.Aeson.Types" "Data.Aeson.TH" "Data.Aeson.QQ.Simple" "Data.Aeson.Encoding.Internal" "Data.Aeson.Internal" "Data.Aeson.Internal.Time" "Data.Aeson.Parser.Internal" "Data.Aeson.Encode" "Data.Aeson.Compat" "Data.Aeson.Encoding.Builder" "Data.Aeson.Internal.Functions" "Data.Aeson.Parser.Unescape" "Data.Aeson.Parser.Time" "Data.Aeson.Types.FromJSON" "Data.Aeson.Types.Generic" "Data.Aeson.Types.ToJSON" "Data.Aeson.Types.Class" "Data.Aeson.Types.Internal" "Data.Attoparsec.Time" "Data.Attoparsec.Time.Internal" "Data.Aeson.Parser.UnescapePure" "-Wall" "-O2" "-hide-all-packages" "-g13" [ 2 of 25] Compiling Data.Aeson.Internal.Functions ( Data\Aeson\Internal\Functions.hs, C:\ghc\msys64\home\Andi\aeson_repro \dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Internal\Functions.o ) [Data.HashMap.Strict changed] [ 5 of 25] Compiling Data.Aeson.Types.Generic ( Data\Aeson\Types\Generic.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Types\Generic.o ) [Prelude.Compat changed] [ 6 of 25] Compiling Data.Aeson.Types.Internal ( Data\Aeson\Types\Internal.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Types\Internal.o ) [Data.Vector changed] [ 7 of 25] Compiling Data.Aeson.Parser.Internal ( Data\Aeson\Parser\Internal.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Parser\Internal.o ) [Data.Scientific changed] [ 8 of 25] Compiling Data.Aeson.Parser ( Data\Aeson\Parser.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Parser.o ) [Data.Aeson.Parser.Internal changed] [ 9 of 25] Compiling Data.Attoparsec.Time.Internal ( attoparsec- iso8601\Data\Attoparsec\Time\Internal.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Attoparsec\Time\Internal.o ) [Prelude.Compat changed] attoparsec-iso8601\Data\Attoparsec\Time\Internal.hs:24:1: warning: [-Wunused-imports] The import of `Unsafe.Coerce' is redundant except perhaps to import instances from `Unsafe.Coerce' To import instances alone, use: import Unsafe.Coerce() | 24 | import Unsafe.Coerce (unsafeCoerce) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ [10 of 25] Compiling Data.Attoparsec.Time ( attoparsec- iso8601\Data\Attoparsec\Time.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Attoparsec\Time.o ) [Data.Attoparsec.Text changed] [11 of 25] Compiling Data.Aeson.Parser.Time ( Data\Aeson\Parser\Time.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Parser\Time.o ) [Data.Attoparsec.Text changed] [12 of 25] Compiling Data.Aeson.Types.FromJSON ( Data\Aeson\Types\FromJSON.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Types\FromJSON.o ) [Data.Primitive.PrimArray changed] [13 of 25] Compiling Data.Aeson.Internal ( Data\Aeson\Internal.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Internal.o ) [Data.Aeson.Types.FromJSON changed] [14 of 25] Compiling Data.Aeson.Internal.Time ( Data\Aeson\Internal\Time.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Internal\Time.o ) [Data.Attoparsec.Time.Internal changed] [15 of 25] Compiling Data.Aeson.Encoding.Builder ( Data\Aeson\Encoding\Builder.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Encoding\Builder.o ) [Data.Vector changed] [16 of 25] Compiling Data.Aeson.Encoding.Internal ( Data\Aeson\Encoding\Internal.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Encoding\Internal.o ) [Data.Scientific changed] [17 of 25] Compiling Data.Aeson.Encoding ( Data\Aeson\Encoding.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Encoding.o ) [Data.Aeson.Encoding.Internal changed] [18 of 25] Compiling Data.Aeson.Types.ToJSON ( Data\Aeson\Types\ToJSON.hs, C:\ghc\msys64\home\Andi\aeson_repro\dist- newstyle\build\x86_64-windows\ghc-8.7.20181025\aeson-1.4.1.0\build\Data\Aeson\Types\ToJSON.o ) [Data.Primitive.PrimArray changed] Access violation in generated code when executing data at 0x103fec440 Attempting to reconstruct a stack trace... Frame Code address * 0x845d9c0 0x103fec440 * 0x845da20 0x400c0f8 E:\ghc_dwarf\inplace\bin\ghc- stage2.exe+0x3c0c0f8 * 0x845da80 0x3fec9a1 E:\ghc_dwarf\inplace\bin\ghc- stage2.exe+0x3bec9a1 * 0x845dab0 0x3feca31 E:\ghc_dwarf\inplace\bin\ghc- stage2.exe+0x3beca31 * 0x845dab8 0x34c8934 E:\ghc_dwarf\inplace\bin\ghc- stage2.exe+0x30c8934 * 0x845dac0 0xfa340 * 0x845dac8 0x2a940b78 * 0x845dad0 0x2a98cd69 * 0x845dad8 0x2a98d7d0 CallStack (from HasCallStack): die', called at .\\Distribution\\Client\\ProjectOrchestration.hs:977:55 in main:Distribution.Client.ProjectOrchestration cabal.exe: Failed to build aeson-1.4.1.0-inplace. The build process terminated with exit code 11 }}} I could only reproduce it with master on Windows so far. It always triggers but under very specific circumstances: * GHC built with the flags above, adding dwarf info to the ghc executable or removing dwarf info eliminates the issue. * Only on a complete rebuild of aeson. Restarting the crashed build finishes without an error. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15808> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15003: Data.List documentation should list complexities of more functions
by GHC 18 Dec '18

18 Dec '18

#15003: Data.List documentation should list complexities of more functions -------------------------------------+------------------------------------- Reporter: gbaz | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: 8.4.3 Component: | Version: 8.2.2 libraries/base | 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: -------------------------------------+------------------------------------- Lots of functions in `Data.List` have overtly obvious complexity, like `delete`. It would still be nice to list all the complexities explicitly, especially for beginners. Also, just to set a good example. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15003> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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