June 2016 - ghc-tickets

[GHC] #11272: Overloaded state-monadic function is not specialised
by GHC 14 May '17

14 May '17

#11272: Overloaded state-monadic function is not specialised -------------------------------------+------------------------------------- Reporter: NickSmallbone | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 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 have a simple typeclass-polymorphic function which fails to specialise. Here is module A which defines the function `overloaded`: {{{#!hs module A where import Control.Monad.Trans.State import Control.Monad overloaded :: Ord a => a -> a -> State () () overloaded x y = do () <- get when (x <= y) (overloaded y x) }}} In module B I use `overloaded` on `Int`s: {{{#!hs module B where import A import Control.Monad.Trans.State specialised :: Int -> Int -> () specialised x y = execState (A.overloaded x y) () }}} Unfortunately the generated code is not specialised but passes an `Ord` dictionary around. It doesn't make any difference if I mark `overloaded` as `INLINEABLE` or not. In the core file, `overloaded` has been worker-wrapper transformed but the worker is marked `INLINEABLE[0]` - so I'm not sure why it's not being specialised. Curiously, if I make `overloaded` be a normal function instead of one in the state monad, or if I replace `() <- get` with simply `get`, specialisation goes through fine. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11272> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11964: Without TypeInType, inconsistently accepts Data.Kind.Type but not type synonym
by GHC 12 May '17

12 May '17

#11964: Without TypeInType, inconsistently accepts Data.Kind.Type but not type synonym -------------------------------------+------------------------------------- Reporter: ezyang | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc2 (Type checker) | 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: -------------------------------------+------------------------------------- For convenience, I'll use GHCi to demonstrate flag behavior. First, we define a file: ``` {-# LANGUAGE TypeInType #-} import Data.Kind type Star = Type newtype T k (t :: k) = T () ``` Next, we load it up in GHCi, WITHOUT `-XTypeInType`. Now we observe strange behavior: ``` ezyang@sabre:~$ ghc-8.0 --interactive C.hs GHCi, version 8.0.0.20160204: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( C.hs, interpreted ) Ok, modules loaded: Main. *Main> :k T Type Int T Type Int :: * *Main> :k T Star Int <interactive>:1:3: error: • Data constructor ‘Star’ cannot be used here (Perhaps you intended to use DataKinds) • In the first argument of ‘T’, namely ‘Star’ In the type ‘T Star Int’ ``` Of course, if we pass `-TypeInType` to GHCi that fixes the problem (BTW, `DataKinds` does NOT solve the problem.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11964> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11966: Surprising behavior with higher-rank quantification of kind variables
by GHC 12 May '17

12 May '17

#11966: Surprising behavior with higher-rank quantification of kind variables -------------------------------------+------------------------------------- Reporter: ocharles | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc3 (Type checker) | Keywords: TypeInType | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Sorry about the rubbish title. I wrote the following code, which type checks: {{{#!hs {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE DataKinds #-} {-# LANGUAGE KindSignatures #-} {-# LANGUAGE PolyKinds #-} {-# LANGUAGE RankNTypes #-} {-# LANGUAGE TypeInType #-} {-# LANGUAGE TypeOperators #-} module Test where import Data.Kind (Type) -- Simplification type family Col (f :: k -> j) (x :: k) :: Type -- Base types data PGBaseType = PGInteger | PGText -- Transformations data Column t = Column Symbol t newtype Nullable t = Nullable t newtype HasDefault t = HasDefault t -- Interpretations data Expr k data Record (f :: forall k. k -> Type) = Record {rX :: Col f ('Column "x" 'PGInteger) ,rY :: Col f ('Column "y" ('Nullable 'PGInteger)) ,rZ :: Col f ('HasDefault 'PGText)} }}} However, if I play with this in GHCI, I can get the following error: {{{ λ> let x = undefined :: Record Expr <interactive>:136:29-32: error: • Expected kind ‘forall k. k -> Type’, but ‘Expr’ has kind ‘forall k. k -> *’ • In the first argument of ‘Record’, namely ‘Expr’ In an expression type signature: Record Expr In the expression: undefined :: Record Expr }}} It seems that if I write {{{#!hs data Expr :: forall k. k -> Type }}} things work, but I'm unclear if/why that is necessary, and the error message certainly needs to be fixed. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11966> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12083: ghc-8.0.1-rc4: tyConRoles sees a TcTyCon
by GHC 12 May '17

12 May '17

#12083: ghc-8.0.1-rc4: tyConRoles sees a TcTyCon -------------------------------------+------------------------------------- Reporter: _deepfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc4 (Type checker) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash Test Case: Yes. | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE UnicodeSyntax #-} import Prelude.Unicode type Constrd a = Num a ⇒ a data ADT a = ADT (Constrd a) ExistentiallyLost data ExistentiallyLost = ∀ u. TC u ⇒ ExistentiallyLost u class u ~ (ATF1 u, ATF2 u) ⇒ TC u where type ATF1 u ∷ * type ATF2 u ∷ * uie_handlers ∷ ADT Int -- Loop: -- - ADT depends on ExistentiallyLost (also the Constrd appendage) -- - ExistentiallyLost depends on TC -- - TC depends on ADT }}} --> {{{ [1 of 1] Compiling Main ( /home/deepfire/src/ghc-testcases /tyconroles-sees-a-tctycon-tyalias.hs, interpreted ) <- ghc: panic! (the 'impossible' happened) (GHC version 8.0.0.20160421 for x86_64-unknown-linux): tyConRoles sees a TcTyCon Constrd Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12083> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11722: No TypeRep for unboxed tuples
by GHC 12 May '17

12 May '17

#11722: No TypeRep for unboxed tuples -------------------------------------+------------------------------------- Reporter: goldfire | 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: -------------------------------------+------------------------------------- This now crashes on GHC HEAD: {{{#!hs {-# LANGUAGE MagicHash #-} {-# LANGUAGE UnboxedTuples #-} module Main where import Data.Typeable import GHC.Exts main :: IO () main = print $ typeOf (Proxy :: Proxy (# Int, Int #)) }}} {{{ $ /opt/ghc/head/bin/ghc -O2 -fforce-recomp Example.hs [1 of 1] Compiling Main ( Example.hs, Example.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.1.20160317 for x86_64-unknown-linux): tyConRep (#,#) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} (Previously, this was rejected with an error message, since you couldn't put an unlifted type as the argument of `Proxy`.) (Copied from comment:28:ticket:11471.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11722> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9450: GHC instantiates Data instances before checking hs-boot files
by GHC 11 May '17

11 May '17

#9450: GHC instantiates Data instances before checking hs-boot files -------------------------------------+------------------------------------- Reporter: alanz | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Keywords: boot,deriving | Operating System: Architecture: x86_64 (amd64) | Unknown/Multiple Difficulty: Unknown | Type of failure: Compile- Blocked By: | time crash Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- When compiling a file with deriving instances in it and making use of boot files, it appears that the derivation is attempted before the boot files are checked for consistency. This can lead to GHC panics, as when compiling GHC after this commit https://github.com/alanz/ghc/commit/c73182ca7345f0debba47d0b17a907bcac27c41f In the attached files, if you try to load HsLit.lhs into ghci it will complain about the missing Data instance, not about the boot file inconsistency. If you remove the Data from the deriving clause of HsOverLit, it complains about the boot file inconsistency. I have not managed to reproduce the original panic in this stripped down environment, but if it is needed to more fully understand the problem I can try again to do that. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9450> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10584: Installation of SFML failed
by GHC 10 May '17

10 May '17

#10584: Installation of SFML failed -------------------------------------+------------------------------------- Reporter: SoleSoul | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- This report is bad because I have no idea what I'm reporting but the compiler asked me to so there you go: % cabal install sfml :( Resolving dependencies... Configuring SFML-0.2.0.0... Building SFML-0.2.0.0... Failed to install SFML-0.2.0.0 Build log ( /home/user/.cabal/logs/SFML-0.2.0.0.log ): Configuring SFML-0.2.0.0... Building SFML-0.2.0.0... Preprocessing library SFML-0.2.0.0... [ 1 of 71] Compiling SFML.Window.WindowHandle ( src/SFML/Window/WindowHandle.hs, dist/build/SFML/Window/WindowHandle.o ) [ 2 of 71] Compiling SFML.SFDisplayable ( src/SFML/SFDisplayable.hs, dist/build/SFML/SFDisplayable.o ) [ 3 of 71] Compiling SFML.SFCopyable ( src/SFML/SFCopyable.hs, dist/build/SFML/SFCopyable.o ) [ 4 of 71] Compiling SFML.System.InputStream ( dist/build/SFML/System/InputStream.hs, dist/build/SFML/System/InputStream.o ) [ 5 of 71] Compiling SFML.SFResource ( src/SFML/SFResource.hs, dist/build/SFML/SFResource.o ) [ 6 of 71] Compiling SFML.Utils ( src/SFML/Utils.hs, dist/build/SFML/Utils.o ) [ 7 of 71] Compiling SFML.Window.VideoMode ( dist/build/SFML/Window/VideoMode.hs, dist/build/SFML/Window/VideoMode.o ) [ 8 of 71] Compiling SFML.Window.Types ( src/SFML/Window/Types.hs, dist/build/SFML/Window/Types.o ) [ 9 of 71] Compiling SFML.Window.Keyboard ( dist/build/SFML/Window/Keyboard.hs, dist/build/SFML/Window/Keyboard.o ) [10 of 71] Compiling SFML.Window.Joystick ( dist/build/SFML/Window/Joystick.hs, dist/build/SFML/Window/Joystick.o ) [11 of 71] Compiling SFML.Window.ContextSettings ( dist/build/SFML/Window/ContextSettings.hs, dist/build/SFML/Window/ContextSettings.o ) [12 of 71] Compiling SFML.Window.Context ( dist/build/SFML/Window/Context.hs, dist/build/SFML/Window/Context.o ) [13 of 71] Compiling SFML.System.Vector3 ( dist/build/SFML/System/Vector3.hs, dist/build/SFML/System/Vector3.o ) [14 of 71] Compiling SFML.System.Vector2 ( dist/build/SFML/System/Vector2.hs, dist/build/SFML/System/Vector2.o ) [15 of 71] Compiling SFML.Window.Mouse ( dist/build/SFML/Window/Mouse.hs, dist/build/SFML/Window/Mouse.o ) [16 of 71] Compiling SFML.Window.Event ( dist/build/SFML/Window/Event.hs, dist/build/SFML/Window/Event.o ) [17 of 71] Compiling SFML.Window.SFWindow ( src/SFML/Window/SFWindow.hs, dist/build/SFML/Window/SFWindow.o ) [18 of 71] Compiling SFML.Window.Window ( dist/build/SFML/Window/Window.hs, dist/build/SFML/Window/Window.o ) [19 of 71] Compiling SFML.System.Time ( dist/build/SFML/System/Time.hs, dist/build/SFML/System/Time.o ) [20 of 71] Compiling SFML.Audio.SFSoundBuffer ( src/SFML/Audio/SFSoundBuffer.hs, dist/build/SFML/Audio/SFSoundBuffer.o ) [21 of 71] Compiling SFML.System.Sleep ( dist/build/SFML/System/Sleep.hs, dist/build/SFML/System/Sleep.o ) [22 of 71] Compiling SFML.System.Clock ( src/SFML/System/Clock.hs, dist/build/SFML/System/Clock.o ) [23 of 71] Compiling SFML.System ( src/SFML/System.hs, dist/build/SFML/System.o ) [24 of 71] Compiling SFML.Window ( src/SFML/Window.hs, dist/build/SFML/Window.o ) [25 of 71] Compiling SFML.Graphics.Types ( src/SFML/Graphics/Types.hs, dist/build/SFML/Graphics/Types.o ) [26 of 71] Compiling SFML.Graphics.SFSmoothTexture ( src/SFML/Graphics/SFSmoothTexture.hs, dist/build/SFML/Graphics/SFSmoothTexture.o ) [27 of 71] Compiling SFML.Graphics.SFShapeResizable ( src/SFML/Graphics/SFShapeResizable.hs, dist/build/SFML/Graphics/SFShapeResizable.o ) [28 of 71] Compiling SFML.Graphics.SFCoordSpace ( src/SFML/Graphics/SFCoordSpace.hs, dist/build/SFML/Graphics/SFCoordSpace.o ) [29 of 71] Compiling SFML.Graphics.SFBindable ( src/SFML/Graphics/SFBindable.hs, dist/build/SFML/Graphics/SFBindable.o ) [30 of 71] Compiling SFML.Graphics.Rect ( dist/build/SFML/Graphics/Rect.hs, dist/build/SFML/Graphics/Rect.o ) [31 of 71] Compiling SFML.Graphics.SFBounded ( src/SFML/Graphics/SFBounded.hs, dist/build/SFML/Graphics/SFBounded.o ) [32 of 71] Compiling SFML.Graphics.SFViewable ( src/SFML/Graphics/SFViewable.hs, dist/build/SFML/Graphics/SFViewable.o ) [33 of 71] Compiling SFML.Graphics.Texture ( src/SFML/Graphics/Texture.hs, dist/build/SFML/Graphics/Texture.o ) [34 of 71] Compiling SFML.Graphics.Transform ( dist/build/SFML/Graphics/Transform.hs, dist/build/SFML/Graphics/Transform.o ) ghc: panic! (the 'impossible' happened) (GHC version 7.10.1 for x86_64-unknown-linux): Simplifier ticks exhausted When trying UnfoldingDone $j_sJFj 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: 190129 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug cabal: Error: some packages failed to install: SFML-0.2.0.0 failed during the building phase. The exception was: ExitFailure 1 cabal install sfml 7.18s user 0.76s system 93% cpu 8.460 total -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10584> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10323: Add Android and iOS Operating Systems in Trac
by GHC 10 May '17

10 May '17

#10323: Add Android and iOS Operating Systems in Trac -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: hvr Type: feature | Status: new request | Milestone: Priority: normal | Version: Component: Trac & Git | Operating System: Unknown/Multiple Keywords: | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- These are sufficiently different from Linux/MacOS X to be distinguished from those Operating System values, and sufficiently mainstream to not fall under Other. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10323> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9120: Cache intermediate powers
by GHC 10 May '17

10 May '17

#9120: Cache intermediate powers ------------------------------------+------------------------------------- Reporter: basvandijk | 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: | ------------------------------------+------------------------------------- `GHC.Float` caches powers of 2 and 10. The arrays of powers are currently constructed using: {{{ expts :: Array Int Integer expts = array (minExpt,maxExpt) [(n,2^n) | n <- [minExpt .. maxExpt]] }}} Unfortunately, the intermediate powers in the `2^n` computation are not stored back in the array, only the result is. I propose to use the following scheme that does store the intermediate powers: {{{ -- | Exponentiation with a cache for the most common numbers. expt :: Integer -> Int -> Integer expt _ e | e < 0 = error "Negative exponent" expt 2 e | e <= maxExpt2 = expts2 ! e | otherwise = expts2 ! maxExpt2 * 2^(e-maxExpt2) expt 10 e | e <= maxExpt10 = expts10 ! e | otherwise = expts10 ! maxExpt10 * 10^(e-maxExpt10) expt base e = base^e maxExpt2 :: Int maxExpt2 = 1100 maxExpt10 :: Int maxExpt10 = 324 expts2 :: Array Int Integer expts2 = expts 2 maxExpt2 expts2 expts10 :: Array Int Integer expts10 = expts 10 maxExpt10 expts10 expts :: Integer -> Int -> Array Int Integer -> Array Int Integer expts base hi arr = listArray (0, hi) $ 1 : base : go 2 where go :: Int -> [Integer] go !ix = xx : base*xx : go (ix+2) where xx = x * x x = arr ! half half = ix `unsafeShiftR` 1 }}} I will attach a patch. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9120> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8875: Track Exceptions
by GHC 10 May '17

10 May '17

#8875: Track Exceptions ----------------------------------------------+---------------------------- Reporter: yokto | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Project (more than a week) | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: ----------------------------------------------+---------------------------- Figure out for each function which exceptions can be thrown by it. This could probably be done by tracking calls to {{{ throw }}} and {{{ catch }}} and their types. The info would probably need to be stored in the .hi files, and could then be displayed by haddock. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8875> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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