May 2016 - ghc-tickets

[GHC] #12017: GHC panics on pattern synonym ‘kindPrimRep’
by GHC 06 May '16

06 May '16

#12017: GHC panics on pattern synonym ‘kindPrimRep’ -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple PatternSynonyms | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# Language PatternSynonyms, GADTs #-} data Ty a where B :: Ty Bool class (Eq a, Ord a, Show a) => GetTy a where getTy :: Ty a instance GetTy Bool where getTy = B data Exp a where Constant :: GetTy a => Ty a -> a -> Exp a pattern MkBool :: () => (GetTy t, Bool ~ t) => t -> Exp t pattern MkBool bool = Constant B bool pattern Tru :: () => Bool ~ t => Exp t pattern Tru = MkBool True }}} with head: {{{ $ ghci -ignore-dot-ghci /tmp/tywM.hs GHCi, version 8.1.20160503: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( /tmp/tywM.hs, interpreted ) ghc: panic! (the 'impossible' happened) (GHC version 8.1.20160503 for x86_64-unknown-linux): kindPrimRep.go rep_a2tC Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug > }}} {{{#!hs pattern Tru :: () => Bool ~ t => Exp t pattern Tru = Constant B True }}} works fine -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12017> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3427: control what sort of entity a deprecated pragma applies to
by GHC 06 May '16

06 May '16

#3427: control what sort of entity a deprecated pragma applies to -------------------------------------+------------------------------------- Reporter: igloo | Owner: thoughtpolice Type: feature request | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 6.10.4 Resolution: | Keywords: deprecate | warning Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): Good! Use the same syntax as the disambiguation in export lists though! Also `pattern`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3427#comment:13> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3427: control what sort of entity a deprecated pragma applies to
by GHC 06 May '16

06 May '16

#3427: control what sort of entity a deprecated pragma applies to -------------------------------------+------------------------------------- Reporter: igloo | Owner: thoughtpolice Type: feature request | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 6.10.4 Resolution: | Keywords: deprecate | warning Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by thoughtpolice): * owner: => thoughtpolice * milestone: => 8.2.1 Comment: By popular demand (read: me), I'm probably going to fix this, because it is super, super annoying in my `ed25519` library, where I want to deprecate some constructors, *not* types, but the types and constructors have the same name. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3427#comment:12> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3427: control what sort of entity a deprecated pragma applies to
by GHC 06 May '16

06 May '16

#3427: control what sort of entity a deprecated pragma applies to -------------------------------------+------------------------------------- Reporter: igloo | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 6.10.4 Resolution: | Keywords: deprecate | warning Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by thomie): * keywords: => deprecate warning * priority: low => normal -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3427#comment:11> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11830: Disabling idle GC leads to freeze
by GHC 05 May '16

05 May '16

#11830: Disabling idle GC leads to freeze -------------------------------------+------------------------------------- Reporter: NeilMitchell | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Runtime | Version: 8.0.1-rc3 System | Keywords: | Operating System: Linux Architecture: | Type of failure: Incorrect result Unknown/Multiple | at runtime Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I'm currently getting a runtime freeze with a spinning CPU with the latest GHC 8.0.1 RC (8.0.0.20160411). Testing 2 months ago on whatever was the latest release candidate showed no problems. The reproduction steps are a bit long winded: * All tested on Ubuntu Linux. * Checkout Shake, https://github.com/ndmitchell/shake.git (currently at 75505baa5fc5d1b99a1162edae6ecf7669f00ed9). * {{{cabal install}}} * Checkout Ninja, https://github.com/ninja-build/ninja.git (currently at 78f548880e549c701bd77760e4b3f3a4ee147641). * Change to the {{{ninja}}} directory. * Run {{{./configure.py --bootstrap}}} * Run {{{cp ninja nin}}} * Run {{{./nin -t clean}}} * Run {{{shake}}} Observe that Shake fails to complete and starts spinning on 1 CPU. If you modify {{{shake.cabal}}} to remove {{{-with-rtsopts=-I0 -qg -qb}}} then it works again and completes in < 1 min. Adding back flags with {{{+RTS -I0 -RTS}}} shows that {{{-I0}}} alone is the culprit. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11830> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 05 May '16

05 May '16

#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 11362 | Blocking: Related Tickets: #10424 | Differential Rev(s): Phab:D910, | Phab:D1073, Phab:D1133, Phab:D1192, | Phab:D1268, Phab:D1360, Phab:D1373, Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468, DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508 -------------------------------------+------------------------------------- Comment (by Bartosz Nitka <niteria@…>): In [changeset:"ad4392c142696d5092533480a82ed65322e9d413/ghc" ad4392c/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="ad4392c142696d5092533480a82ed65322e9d413" Kill non-deterministic foldUFM in TrieMap and TcAppMap Summary: foldUFM introduces unnecessary non-determinism that actually leads to different generated code as explained in Note [TrieMap determinism]. As we're switching from UniqFM to UniqDFM here you might be concerned about performance. There's nothing that ./validate detects. nofib reports no change in Compile Allocations, but Compile Time got better on some tests and worse on some, yielding this summary: -1 s.d. ----- -3.8% +1 s.d. ----- +5.4% Average ----- +0.7% This is not a fair comparison as the order of Uniques changes what GHC is actually doing. One benefit from making this deterministic is also that it will make the performance results more stable. Full nofib results: P108 Test Plan: ./validate, nofib Reviewers: goldfire, simonpj, simonmar, austin, bgamari Reviewed By: simonpj Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2169 GHC Trac Issues: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:158> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11999: expressing injectivity on functional dependencies gives orphan instances warnings
by GHC 04 May '16

04 May '16

#11999: expressing injectivity on functional dependencies gives orphan instances warnings -------------------------------------+------------------------------------- Reporter: dredozubov | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 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: -------------------------------------+------------------------------------- Class.hs {{{ {-# LANGUAGE DataKinds, FlexibleInstances, FunctionalDependencies, KindSignatures, MultiParamTypeClasses, TypeFamilies #-} module Class where class C a b | a -> b, b -> a }}} Lib.hs {{{ {-# LANGUAGE DataKinds, FlexibleInstances, MultiParamTypeClasses, TypeFamilies #-} module Lib where import Class newtype Local = Local () instance C Local () }}} gives {{{ /Users/dr/workspace/broken-ophans-ghc/src/Lib.hs:10:1: warning: [-Worphans] Orphan instance: instance C Local () To avoid this move the instance declaration to the module of the class or of the type, or wrap the type with a newtype and declare the instance on the new type. }}} It seems weird to me and it is either a bug in the orphan instances checker or there is some fundamental aspect which i don't undestand. I've been able to reproduce this with 7.10.3 and 8-rc4. I've compiled a git repo with minimalistic example of this: [https://github.com/dredozubov/broken-instances-minimal] -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11999> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12006: Can't infer constraint of pattern synonyms
by GHC 03 May '16

03 May '16

#12006: Can't infer constraint of pattern synonyms -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Keywords: TypeSynonyms | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Can't infer constraint of: {{{#!hs -- pattern Real' :: Num a => a -> Complex a pattern Real' r <- r :+ _ where Real' r = r :+ 0 }}} {{{ teR4.hs:12:25: error: … • No instance for (Num t) arising from the literal ‘0’ Possible fix: add (Num t) to the context of the type signature for: Main.$bReal' :: t -> Complex t • In the second argument of ‘(:+)’, namely ‘0’ In the expression: r :+ 0 In an equation for ‘$bReal'’: $bReal' r = r :+ 0 Compilation failed. }}} Should it be able to? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12006> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12008: GHCi autocomplete text following cursor/insertion point
by GHC 03 May '16

03 May '16

#12008: GHCi autocomplete text following cursor/insertion point -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 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: -------------------------------------+------------------------------------- The autocomplete doesn't look at what follows the cursor. `␣` denotes insertion point, don't mind the smiley {{{ ghci> import Control.␣.Fail }}} Tab is pressed, this is what I'd like happen: {{{ ghci> import Control.Monad.Fail }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12008> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7353: Make system IO interruptible on Windows
by GHC 03 May '16

03 May '16

#7353: Make system IO interruptible on Windows -------------------------------------+------------------------------------- Reporter: joeyadams | Owner: refold Type: bug | Status: new Priority: normal | Milestone: Component: Core Libraries | Version: 7.6.1 Resolution: | Keywords: Operating System: Windows | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by Phyx-): * owner: => refold Comment: @refold that sounds great, thanks for doing this! Let me know if you need any help. In the mean time I'll assign the ticket to you. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7353#comment:30> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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