January 2017 - ghc-tickets

[GHC] #13134: Simplifier ticks exhausted
by GHC 16 Jan '17

16 Jan '17

#13134: Simplifier ticks exhausted -------------------------------------+------------------------------------- Reporter: fumieval | Owner: Type: task | Status: new Priority: low | Milestone: Component: Compiler | Version: 8.0.2 Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- When compiling generics-rich code I got this panic. I had to increase `-fsimpl-tick-factor` to 110 to fix the problem. {{{ <no location info>: error: ghc: panic! (the 'impossible' happened) (GHC version 8.0.2 for x86_64-unknown-linux): Simplifier ticks exhausted When trying UnfoldingDone f_s1dfn 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: 19189 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} I attached the output of `-ddump-simpl-stats`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13134> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13131: add effectful version of atomicModifyMutVar#
by GHC 15 Jan '17

15 Jan '17

#13131: add effectful version of atomicModifyMutVar# -------------------------------------+------------------------------------- Reporter: carter | Owner: Type: feature | Status: new request | 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: -------------------------------------+------------------------------------- something like {{{ atomicEffectfulModifyMutVar# :: MutVar# s a -> ((# a, State# s #) -> (# State# s , a , b#)) -> State# s -> (#State# s, b #) }}} this isn't quite safely expressible currently without some unsafeCoercion highjinks that I'm not sure are robust -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13131> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7206: Implement cheap build
by GHC 15 Jan '17

15 Jan '17

#7206: Implement cheap build -------------------------------------+------------------------------------- Reporter: simonpj | Owner: simonpj Type: bug | Status: new Priority: normal | Milestone: ⊥ Component: Compiler | Version: 7.4.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: #8763 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by akio): * cc: akio (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7206#comment:21> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13125: GHC Panics when encoding Russel's paradox using GADTs
by GHC 15 Jan '17

15 Jan '17

#13125: GHC Panics when encoding Russel's paradox using GADTs -------------------------------------+------------------------------------- Reporter: tysonzero | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: panic, GADTs | Operating System: MacOS X Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The following encoding of Russel's paradox using GADTs causes GHC to panic, which is understandable as it involves creating a value of an uninhabited data type without using any recursion, which should not be possible as far as I can tell, so this should probably not type check. {{{#!hs {-# LANGUAGE GADTs #-} data False data R a where MkR :: (c (c ()) -> False) -> R (c ()) condFalse :: R (R ()) -> False condFalse x@(MkR f) = f x absurd :: False absurd = condFalse (MkR condFalse) main :: IO () main = absurd `seq` print () }}} When compiled with optimization I get: {{{ ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-apple-darwin): Simplifier ticks exhausted When trying UnfoldingDone condFalse 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: 6441 }}} When I instead load it into GHCi and type "absurd `seq` ()" I get: {{{ ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-apple-darwin): atomPrimRep case absurd of _ [Occ=Dead] { } }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13125> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7401: Can't derive instance for Eq when datatype has no constructor, while it is trivial do do so.
by GHC 15 Jan '17

15 Jan '17

#7401: Can't derive instance for Eq when datatype has no constructor, while it is trivial do do so. -------------------------------------+------------------------------------- Reporter: jpbernardy | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.1 Resolution: | Keywords: deriving, | newcomer Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: #10577, #13117 | Differential Rev(s): Phab:D978 Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * related: => #10577, #13117 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7401#comment:48> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13108: Improve poor Access Violation reporting on Windows
by GHC 15 Jan '17

15 Jan '17

#13108: Improve poor Access Violation reporting on Windows -------------------------------------+------------------------------------- Reporter: awson | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Runtime | Version: System | Keywords: | Operating System: Windows Architecture: | Type of failure: Poor/confusing Unknown/Multiple | error message Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Currently all that we have is "Segmentation fault/access violation in generated code" message. My patch adds type (read/write/dep violation) and location information to the diagnostics. This may help tremendously when analyzing the problems. Please, apply. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13108> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12998: libraries/base/System/Posix/Types.hs: tries to define Floating instance for opaque type
by GHC 15 Jan '17

15 Jan '17

#12998: libraries/base/System/Posix/Types.hs: tries to define Floating instance for opaque type -------------------------------------+------------------------------------- Reporter: slyfox | 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: -------------------------------------+------------------------------------- I've noticed it as a build failure on openbsd-6 but on linux behaviour is strange as well. Build failure: {{{ libraries/base/System/Posix/Types.hs:217:100: error: * No instance for (Fractional Int32) arising from the 'deriving' clause of a data type declaration Possible fix: use a standalone 'deriving instance' declaration, so you can specify the instance context yourself * When deriving the instance for (Fractional CTimer) }}} On openbsd-6.0 timer_t is an int32: {{{ # gcc -E /usr/include/time.h | grep timer_t typedef __int32_t __timer_t; typedef __timer_t timer_t; }}} On amd64-linux-glibc it's void*: {{{ $ gcc -E /usr/include/time.h | grep timer_t typedef void * __timer_t; typedef __timer_t timer_t; }}} But base's configure detects it as Double (by chance) on amd64-linux- glibc. {{{ System.Posix.Types> :t CTimer CTimer :: Double -> CTimer }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12998> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12795: Add more types to System.Posix.Types
by GHC 15 Jan '17

15 Jan '17

#12795: Add more types to System.Posix.Types -------------------------------------+------------------------------------- Reporter: DanielG | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: | Version: 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: -------------------------------------+------------------------------------- A whole lot of types are still missing from `System.Posix.Types` as noted in a TODO comment in the code: {{{ --- ToDo: blksize_t, clockid_t, blkcnt_t, fsblkcnt_t, fsfilcnt_t, id_t, key_t --- suseconds_t, timer_t, useconds_t }}} Specifically the lack of wrappers for blkcnt_t is causing trouble because it's forcing HFuse to re-implement `unix`'s `FileStatus` type to include the missing `st_blocks` field. See [https://hackage.haskell.org/package/HFuse/docs/System- Fuse.html#t:FileStat FileStat docs on Hackage]. I have patches for `base` and `unix` ready to add wrappers for all the types the comment mentions, let's see if I can figure out how to use Phab ;) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12795> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10073: Idris REPL is pretty and we can too
by GHC 14 Jan '17

14 Jan '17

#10073: Idris REPL is pretty and we can too -------------------------------------+------------------------------------- Reporter: bitemyapp | Owner: Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.8.4 Component: GHCi | Operating System: Unknown/Multiple Keywords: | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Manual for configuring colors in the Idris REPL: https://github.com/idris- lang/Idris-dev/wiki/Manual#colours Screenshot: http://i.imgur.com/rYHCI4T.png Particularly, I'd like to make type errors and warnings more visually distinct. I think little touches like this can go a long way to making it nice to work with Haskell code. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10073> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12766: Allow runtime-representation polymorphic data families
by GHC 14 Jan '17

14 Jan '17

#12766: Allow runtime-representation polymorphic data families -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: TypeInType | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #12369 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This is an offshoot of #12369 (‘ data families shouldn't be required to have return kind *, data instances should’), allowing family declarations something like: {{{#!hs data family Array a :: TYPE rep }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12766> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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