February 2018 - ghc-tickets

[GHC] #14699: Library status for 8.4.1
by GHC 08 Mar '18

08 Mar '18

#14699: Library status for 8.4.1 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: highest | Milestone: 8.4.1 Component: Compiler | 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: -------------------------------------+------------------------------------- * `Cabal`: needs release * `Win32`: on-release * `array`: Needs revision * `binary`: on-release * `bytestring`: on-release * `containers`: needs release: https://github.com/haskell/containers/issues/501 * `deepseq`: needs revision * `directory`: on-release * `filepath`: needs release: https://github.com/haskell/filepath/issues/65 * `haskeline`: needs release: https://github.com/judah/haskeline/issues/75 * `hpc`: needs release * `mtl`: needs release: https://github.com/haskell/mtl/issues/52 * `parallel`: needs revision * `parsec`: needs release: https://github.com/haskell/parsec/issues/86 * `pretty`: needs release: https://github.com/haskell/pretty/issues/47 * `primitive`: needs release: https://github.com/haskell/primitive/issues/72 * `process`: needs release: https://github.com/haskell/primitive/issues/72 * `stm`: needs release: #14698 * `terminfo`: needs release: https://github.com/judah/terminfo/issues/27 * `text`: needs release: https://github.com/haskell/text/issues/215 * `time`: on-release * `transformers`: needs update: #14678 * `unix`: needs release: https://github.com/haskell/unix/issues/106 * `haddock`: needs release: https://github.com/haskell/haddock/issues/737 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14699> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14431: Peculiar RTS crash on OS X
by GHC 08 Mar '18

08 Mar '18

#14431: Peculiar RTS crash on OS X ----------------------------------------+--------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Keywords: | Operating System: MacOS X Architecture: Unknown/Multiple | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+--------------------------------- This [[https://phabricator.haskell.org/harbormaster/build/36804/|Harbormaster build]] failed with an odd RTS crash from the stage0 compiler (which is 8.2.1), {{{ ghc: internal error: RELEASE_LOCK: I do not own this lock: rts/posix/itimer/Pthread.c 187 (GHC version 8.2.1 for x86_64_apple_darwin) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} It's not immediately clear to me from the implementation how this could happen, but I thought I should at least note the issue. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14431> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14538: forkprocess01 fails occassionally on with multiple ACQUIRE_LOCK panic
by GHC 08 Mar '18

08 Mar '18

#14538: forkprocess01 fails occassionally on with multiple ACQUIRE_LOCK panic ----------------------------------------+--------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 8.2.1 Keywords: | Operating System: MacOS X Architecture: Unknown/Multiple | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+--------------------------------- I noticed that `forkprocess01` failed to build on Darwin and commit eb86e867694bceedfb47a527d71429197ffe6dda with {{{ Stderr ( forkprocess01 ): forkprocess01: internal error: multiple ACQUIRE_LOCK: rts/Task.c 228 (GHC version 8.3.20171128 for x86_64_apple_darwin) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug /bin/sh: line 1: 5124 Abort trap: 6 ./forkprocess01 +RTS -ls -RTS *** unexpected failure for forkprocess01(threaded1_ls) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14538> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11330: Test `dynamic-paper` fails with core lint error (hpc) and "Simplifier ticks exhausted" (optasm)
by GHC 07 Mar '18

07 Mar '18

#11330: Test `dynamic-paper` fails with core lint error (hpc) and "Simplifier ticks exhausted" (optasm) -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.11 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: -------------------------------------+------------------------------------- {{{ $ ghc-head --info | grep Project [("Project name","The Glorious Glasgow Haskell Compilation System") ,("Project version","8.1.20151231") ,("Project Git commit id","8afeaad919dc67643b4eff14efafb48b59039b2b") }}} {{{ $ make slowtest TEST=dynamic-paper VERBOSE=2 TEST_HC=ghc-head ... =====> dynamic-paper(normal) 1 of 1 [0, 0, 0] =====> dynamic-paper(hpc) 1 of 1 [0, 0, 0] ... Compile failed (status 256) errors were: *** Core Lint errors : in result of Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = True}) *** <no location info>: warning: In a case alternative: (TypeRepX k_s7Ec :: *, a_s7Ed :: k_a5px, tr2_s7Ee :: TypeRep a_s7Ed) @ k_a5px is out of scope *** Offending Program *** ... <no location info>: error: Compilation had errors *** unexpected failure for dynamic-paper(hpc) =====> dynamic-paper(optasm) 1 of 1 [0, 1, 0] Compile failed (status 256) errors were: ghc: panic! (the 'impossible' happened) (GHC version 8.1.20151231 for x86_64-unknown-linux): Simplifier ticks exhausted When trying UnfoldingDone delta1 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: 203160 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug *** unexpected failure for dynamic-paper(optasm) Unexpected results from: TEST="dynamic-paper" }}} This test was added in commit 52da6bdc17bb491d6d2f462b3680eb44b9be92e5: {{{ Author: Richard Eisenberg <eir(a)cis.upenn.edu> Date: Sat Dec 26 09:11:33 2015 -0500 Have mkCastTy look more closely for reflexivity. This may have performance implications. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11330> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12506: Compile time regression in GHC 8.
by GHC 07 Mar '18

07 Mar '18

#12506: Compile time regression in GHC 8. -------------------------------------+------------------------------------- Reporter: deech | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 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 bug is entirely reproducible but unfortunately takes some setup. I don't have a minimal example. The regression is happening in FLTKHS (https://github.com/deech/fltkhs) the Haskell bindings to the FLTK(http://fltk.org) toolkit, and in particular to this GUI (https://github.com/deech/fltkhs/blob/master/images /tree-complex-windows.png). In GHC 7.8, it taks 5-9 seconds to compile and link in 7.10.3, that goes up to 12-15 seconds and finally in GHC 8 it shoots up to 45 seconds. While these numbers come from my i7, 16GB RAM Linux laptop, the compile time regression is proportionally reproducible across machines and operating systems. Here are the steps to reproduce it * Install FLTK Please follow the instructions here (https://github.com/deech/fltkhs #linux-and-bsd) but only the first set which about for installing FLTK 1.3. * Clone the repo with the offending application: `git clone https://github.com/deech/fltkhs-fluid-demos` * Build the application and reproduce the problem: - `cabal install fltkhs` - At the root of the repo do `cabal build fltkhs-fluid-tree` -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12506> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14785: accumArray is too lazy
by GHC 07 Mar '18

07 Mar '18

#14785: accumArray is too lazy -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Core | Version: 8.2.2 Libraries | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Other Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- According to the documentation, {{{#!hs -- If the accumulating function is strict, then 'accumArray' is strict in -- the values, as well as the indices, in the association list. Thus, -- unlike ordinary arrays built with 'array', accumulated arrays should -- not in general be recursive. }}} I believe that strictness is desirable, because it prevents thunks from accumulating when we use the passed function. But the strictness isn't actually there! We never force the result of the function. I believe we should fix the code (and documentation) to maintain the invariant that all elements in the result of `accumArray` are in WHNF. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14785> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14105: ApplicativeDo causes GHC panic on irrefutable list pattern match
by GHC 06 Mar '18

06 Mar '18

#14105: ApplicativeDo causes GHC panic on irrefutable list pattern match -------------------------------------+------------------------------------- Reporter: BoteboTsebo | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Keywords: ApplicativeDo | Operating System: Unknown/Multiple Architecture: x86_64 | Type of failure: None/Unknown (amd64) | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- So this just happened: {{{#!hs {-# language ApplicativeDo #-} module Main where main :: IO () main = do [_] <- pure [] pure () }}} Compiling (under Stack) with `stack exec -- ghc --make src/Main.hs` yields {{{ [1 of 1] Compiling Main ( src/Main.hs, src/Main.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.2.1 for x86_64-unknown-linux): isStrictPattern Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} This does not happen on GHC-8.0.2. It does not happen when `ApplicativeDo` is not activated. It also does not happen when the pattern match line is changed to {{{#!hs [] <- pure [] }}} For completeness, the compiler used by `stack` is that which comes with `nightly-2017-08-10`. I am on Linux x64 (Ubuntu). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14105> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14840: QuantifiedConstraints: Can't define class alias
by GHC 05 Mar '18

05 Mar '18

#14840: QuantifiedConstraints: Can't define class alias -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Keywords: | Operating System: Unknown/Multiple QuantifiedConstraints wipT2893 | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# Language TypeInType, MultiParamTypeClasses, TypeFamilies, FlexibleContexts, FunctionalDependencies, AllowAmbiguousTypes, QuantifiedConstraints, GADTs, ConstraintKinds, KindSignatures, RankNTypes, FlexibleInstances, UndecidableInstances, TypeOperators #-} import Data.Kind class Reifies s a | s -> a where reflect :: proxy s -> a newtype Lift :: forall k. (Type -> Constraint) -> Type -> k -> Type where Lift :: a -> Lift cls a s data family Def :: (k -> Constraint) -> (k -> Type) class (forall s a. Reifies s (Def cls a) => cls (Lift cls a s)) => ReifiableConstraint cls instance (forall s a. Reifies s (Def cls a) => cls (Lift cls a s)) => ReifiableConstraint cls }}} gives an error {{{ $ ghci -ignore-dot-ghci Bug.hs GHCi, version 8.5.20180128: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( /tmp/Bug.hs, interpreted ) /tmp/Bug.hs:14:10: error: • Could not deduce: cls (Lift cls a s) arising from the superclasses of an instance declaration from the context: forall (s :: k) a. Reifies s (Def cls a) => cls (Lift cls a s) bound by the instance declaration at /tmp/Bug.hs:14:10-93 or from: Reifies s (Def cls a) bound by a quantified context at /tmp/Bug.hs:1:1 • In the instance declaration for ‘ReifiableConstraint cls’ | 14 | instance (forall s a. Reifies s (Def cls a) => cls (Lift cls a s)) => ReifiableConstraint cls | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Failed, no modules loaded. Prelude> }}} This is a rare occasion that the class alias trick fails for me so ~+~yay~+~. But is it intended? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14840> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12158: ghc: panic! (the 'impossible' happened) translateConPatVec: lookup
by GHC 05 Mar '18

05 Mar '18

#12158: ghc: panic! (the 'impossible' happened) translateConPatVec: lookup -------------------------------------+------------------------------------- Reporter: wozgonon | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 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: -------------------------------------+------------------------------------- *Main> price Stock{name=name,ric=ric,price=price} = price ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-unknown-mingw32): translateConPatVec: lookup Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12158> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14862: Switching to Cabal 2.2 makes ghc unusable
by GHC 05 Mar '18

05 Mar '18

#14862: Switching to Cabal 2.2 makes ghc unusable -------------------------------------+------------------------------------- Reporter: alpmestan | Owner: (none) Type: bug | Status: new Priority: high | Milestone: Component: None | Version: 8.4.1-alpha3 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: -------------------------------------+------------------------------------- When bumping Cabal to 2.2 as done [https://phabricator.haskell.org/D4453 here], we end up with a stage 1 GHC that seemingly cannot build a non- segfaulting program. For instance, if one builds the following trivial program with a stage 1 built from the ghc-8.4 branch + the patch above... {{{#!hs import System.Exit main = exitSuccess }}} Then... {{{#!sh $ ./foo Segmentation fault }}} So of course, when we proceed and build stage 2, and then build things with stage 2, all the stage2 commands crash. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14862> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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