July 2018 - ghc-tickets

[GHC] #15213: 32 bit Haddock runs out of memory compiling 32 bit GHC
by GHC 23 Aug '18

23 Aug '18

#15213: 32 bit Haddock runs out of memory compiling 32 bit GHC --------------------------------+------------------------------------- Reporter: Phyx- | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Keywords: | Operating System: Unknown/Multiple Architecture: x86 | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------+------------------------------------- Final parts of stage2 fails with {{{ Warning: DriverBkp: could not find link destinations for: BkpEnv BkpM backpackProgressMsg haddock.exe: Out of memory make[1]: *** [compiler/ghc.mk:448: compiler/stage2/doc/html/ghc/ghc.haddock] Error 251 make: *** [Makefile:127: all] Error 2 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15213> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15165: GHC 8.2.2: internal error with +RTS -hb
by GHC 23 Aug '18

23 Aug '18

#15165: GHC 8.2.2: internal error with +RTS -hb --------------------------------------+---------------------------------- Reporter: kfiz | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.2.2 Keywords: | Operating System: MacOS X Architecture: x86_64 (amd64) | Type of failure: Runtime crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------------+---------------------------------- Hi, I'm trying to generate a heap profile via "+RTS -hb" on macOS 10.13.4. Unfortunately I get the following error: `internal error: Invalid object in processHeapClosureForDead(): 7`\\ `(GHC version 8.2.2 for x86_64_apple_darwin)`\\ `Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug`\\ `Abort trap: 6` Best regards Doro -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15165> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15087: Internal Error with Bibliography Profiling
by GHC 23 Aug '18

23 Aug '18

#15087: Internal Error with Bibliography Profiling -------------------------------------+------------------------------------- Reporter: crockeea | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Runtime crash Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- When running my large program with `+RTS -hb`, I get the following error: {{{ internal error: Invalid object in processHeapClosureForDead(): 7 (GHC version 8.4.2 for x86_64_unknown_linux) }}} Unfortunately, I'm unable to find a minimal example. (Side note: I doubt this is relevant, but this is a multi-threaded program. I first tried to profile with `+RTS -N4 -hb`, but got `-hb cannot be used with multiple capabilities`. I assumed this means it doesn't like `-N4` with `-hb`, so I removed `-N4` and got the above error.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15087> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14973: Location in GHCi debugger prompt printed twice when default prompt is used
by GHC 23 Aug '18

23 Aug '18

#14973: Location in GHCi debugger prompt printed twice when default prompt is used -------------------------------------+------------------------------------- Reporter: osa1 | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 8.5 Keywords: debugger | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- (Noticed in #8316) Test.hs: {{{#!haskell foo :: [Int] foo = [ 1 .. 10 ] }}} Reproducer: {{{ $ ghc-stage2 --interactive -ignore-dot-ghci Test.hs GHCi, version 8.5.20180325: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( Test.hs, interpreted ) Ok, one module loaded. *Main> :break foo Breakpoint 0 activated at Test.hs:2:7-14 *Main> foo Stopped in Main.foo, Test.hs:2:7-14 _result :: [Int] = _ [Test.hs:2:7-14] [Test.hs:2:7-14] *Main> }}} The `[Test.hs:2:7-14]` part is repeated. Setting the prompt fixes it: {{{ $ ghc-stage2 --interactive Test.hs -ignore-dot-ghci GHCi, version 8.5.20180325: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( Test.hs, interpreted ) Ok, one module loaded. *Main> :set prompt "> " > :break foo Breakpoint 0 activated at Test.hs:2:7-14 > foo Stopped in Main.foo, Test.hs:2:7-14 _result :: [Int] = _ [Test.hs:2:7-14] > }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14973> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15390: Figure out why CircleCI isn't generating haddocks
by GHC 23 Aug '18

23 Aug '18

#15390: Figure out why CircleCI isn't generating haddocks -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: highest | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 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: -------------------------------------+------------------------------------- -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15390> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15059: ghcpkg05 fails
by GHC 23 Aug '18

23 Aug '18

#15059: ghcpkg05 fails -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.6.1 Component: Test Suite | Version: 8.2.2 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: -------------------------------------+------------------------------------- Several people have noted that `ghcpkg05` seems to fail in some environments with (taken from CircleCI, https://circleci.com/gh/ghc/ghc/3654) {{{ --- ./cabal/ghcpkg05.run/ghcpkg05.stderr.normalised 2018-04-19 14:14:29.043902308 +0000 +++ ./cabal/ghcpkg05.run/ghcpkg05.run.stderr.normalised 2018-04-19 14:14:29.043902308 +0000 @@ -10,6 +10,13 @@ cannot find any of ["C/D.hi","C/D.p_hi","C/D.dyn_hi"] cannot find any of ["C/E.hi","C/E.p_hi","C/E.dyn_hi"] cannot find any of ["libtestpkg-2.0-XXX.a","libtestpkg-2.0-XXX.p_a","libtestpkg-2.0-XXX- ghc<VERSION>.so","libtestpkg-2.0-XXX-ghc<VERSION>.dylib","testpkg-2.0-XXX- ghc<VERSION>.dll"] on library path +Warning: include-dirs: /home/ghc/project/compiler/stage2/build/utils doesn't exist or isn't a directory +Warning: include-dirs: /home/ghc/project/compiler/stage2/build/../rts/dist/build doesn't exist or isn't a directory +Warning: include-dirs: /home/ghc/project/compiler/stage2/build/stage2 doesn't exist or isn't a directory +Warning: include-dirs: /home/ghc/project/libraries/haskeline/dist- install/build/includes doesn't exist or isn't a directory +Warning: include-dirs: /home/ghc/project/libraries/text/dist- install/build/include doesn't exist or isn't a directory +Warning: include-dirs: /home/ghc/project/libraries/containers/dist- install/build/include doesn't exist or isn't a directory +Warning: include-dirs: /home/ghc/project/libraries/bytestring/dist- install/build/include doesn't exist or isn't a directory The following packages are broken, either because they have a problem listed above, or because they depend on a broken package. *** unexpected failure for ghcpkg05(normal) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15059> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10100: Bogus "redundant constraint" warning with functional dependencies
by GHC 23 Aug '18

23 Aug '18

#10100: Bogus "redundant constraint" warning with functional dependencies -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Compiling this code with GHC HEAD: {{{#!hs {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE FunctionalDependencies #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE UndecidableInstances #-} module T10100 where data Zero data Succ a class Add a b ab | a b -> ab, a ab -> b instance Add Zero b b instance (Add a b ab) => Add (Succ a) b (Succ ab) }}} Gives a bogus warning about redundant constraint: {{{ Redundant constraint: Add a b ab In the instance declaration for ‘Add (Succ a) b (Succ ab)’ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10100> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14336: ghci leaks memory
by GHC 23 Aug '18

23 Aug '18

#14336: ghci leaks memory -------------------------------------+------------------------------------- Reporter: NeilMitchell | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 8.2.1 Keywords: | Operating System: Windows Architecture: x86_64 | Type of failure: Runtime (amd64) | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The following script spawns ghci, and that spawned ghci then goes on to leak memory: {{{#!hs import Control.Concurrent import Control.Monad import System.IO import System.Process main = do (Just hin, Nothing, Nothing, pid) <- createProcess (proc "ghci" ["+RTS","-S"]){std_in=CreatePipe} forever $ do threadDelay 100000 -- 0.1s hPutStrLn hin "\"this is a test of outputting stuff\"" hFlush hin }}} This script just writes a string to GHCi, which then echos it back. The {{{+RTS -S}}} is useful to watch the live memory tick up in realtime, but it leaks without it, and the leak can be seen in process explorer (87Mb to 700Mb over about 30 minutes). While repeatedly writing commands may not be a standard usage of ghci, it is when driven by tools such as ghcid (https://hackage.haskell.org/package/ghcid) and other IDE-like uses. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14336> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14917: Allow levity polymorhism in binding position
by GHC 22 Aug '18

22 Aug '18

#14917: Allow levity polymorhism in binding position -------------------------------------+------------------------------------- Reporter: andrewthad | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 Keywords: | Operating System: Unknown/Multiple LevityPolymorphism | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The main problem with levity polymorphism in a binding position is that it's impossible to do codegen since the calling convention depending on the instantiation of the runtime representation variable. From the paper, we have the following rejected example code: {{{ bTwice :: ∀ (r :: RuntimeRep) (a :: TYPE r). Bool → a → (a → a) → a }}} However, if you are able to inline the function, this problem disappears. You would need a guarantee stronger than what the `INLINE` pragma provides though since the `INLINE` pragma still allows the function to be fed as an argument to a higher-order function. I'll refer to a hypothetical new pragma as `INLINE MANDATE`. This pragma causes a compile-time error to be admitted if the function is ever used in a way that would cause it to not be inlined. Now `bTwice` would be writeable: {{{ {-# INLINE MANDATE #-} bTwice :: ∀ (r :: RuntimeRep) (a :: TYPE r). Bool → a → (a → a) → a }}} The function definition would be provide in the `.hi` file just as it would be for a function marked as `INLINE`, but unlike the `INLINE` counterpart, there would be no generated code for this function, since generating the code would be impossible. I have several uses for this in mind. I often want a levity-polymorphic variant `ST`. With `INLINE MANDATE`, I still wouldn't get `do` notation, but I could write: {{{ -- This newtype is already allowed today newtype STL s (a :: TYPE r) = STL (State# s -> (# s, a #) #) intA, intB, intC :: STL s Int# wordA, wordB :: Int# -> STL s Word# {-# INLINE MANDATE #-} (>>=.) :: STL s a -> (a -> STL s b) -> STL s b STL a >>=. g = STL (\s0 -> case a s0 of (# s1, v #) -> case g v of STL f -> f s1 myFunc :: STL s Word# myFunc = intA >>=. \a -> intB >>=. \b -> intC >>=. \c -> wordA a >>=. \wa -> wordB b >>=. \wb -> ... -- do something with the data }}} I would appreciate any feedback on this. If there's something that makes this fundamentally impossible, that would be good to know. Or if other people feel like this would be useful, that would be good to know as well. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14917> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14111: strange error when using data families with levity polymorphism and unboxed sums and data families
by GHC 22 Aug '18

22 Aug '18

#14111: strange error when using data families with levity polymorphism and unboxed sums and data families -------------------------------------+------------------------------------- Reporter: carter | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 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: -------------------------------------+------------------------------------- I've the following small example {{{ {-# LANGUAGE MagicHash, UnboxedSums, NoImplicitPrelude #-} {-# LANGUAGE TypeFamilies #-} -- {-# LANGUAGE PolyKinds #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE FunctionalDependencies #-} {-# LANGUAGE TypeInType #-} {-# LANGUAGE GADTs ,ExplicitNamespaces#-} {-# LANGUAGE UnboxedTuples #-} module Data.Unboxed.Maybe where import GHC.Exts import GHC.Types import Prelude (undefined) import Data.Void data family Maybe(x :: TYPE (r :: RuntimeRep)) data instance Maybe (a :: * ) where MaybeSum :: (# a | (# #) #) -> Maybe a data instance Maybe (x :: TYPE 'UnliftedRep) where MaybeSumU :: (# x | (# #) #) -> Maybe x }}} and then i get the error (made much saner to read by use of printing explicit kinds) {{{ Prelude> :r [1 of 1] Compiling Data.Unboxed.Maybe ( src/Data/Unboxed/Maybe.hs, interpreted ) src/Data/Unboxed/Maybe.hs:22:3: error: • Data constructor ‘MaybeSumU’ returns type ‘Maybe 'LiftedRep x’ instead of an instance of its parent type ‘Maybe 'UnliftedRep x’ • In the definition of data constructor ‘MaybeSumU’ In the data instance declaration for ‘Maybe’ | 22 | MaybeSumU :: (# x | (# #) #) -> Maybe x }}} this is a) a case where printing runtime reps makes things easier to debug :) b) a very confusing type error since the data instance clearly says "x :: TYPE 'UnliftedRep " is there something i'm overlooking, or is this a bug? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14111> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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