May 2016 - ghc-tickets

[GHC] #11993: RFC, allow local bindings in pattern synonyms
by GHC 25 May '16

25 May '16

#11993: RFC, allow local bindings in pattern synonyms -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 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: -------------------------------------+------------------------------------- Code from #11992, allow users to write something like {{{#!hs pattern Suc :: Int -> Int pattern Suc n <- (hasSuc -> Just n) where Suc n = n + 1 hasSuc :: Int -> Maybe Int hasSuc n = [ n - 1 | n > 0 ] }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11993> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1965: Allow unconstrained existential contexts in newtypes
by GHC 25 May '16

25 May '16

#1965: Allow unconstrained existential contexts in newtypes -------------------------------------+------------------------------------- Reporter: guest | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 6.8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by simonpj: @@ -9,0 +9,2 @@ + + The wiki page [wiki:NewtypeOptimizationForGADTS] summarises the proposal New description: Declarations like {{{ newtype Bar = forall a. Bar (Foo a) }}} ought to be allowed so long as no typeclass constraints are added. Right now, this requires data rather than newtype. The wiki page [wiki:NewtypeOptimizationForGADTS] summarises the proposal -- -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1965#comment:30> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1965: Allow unconstrained existential contexts in newtypes
by GHC 25 May '16

25 May '16

#1965: Allow unconstrained existential contexts in newtypes -------------------------------------+------------------------------------- Reporter: guest | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 6.8.1 Resolution: | Keywords: 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 dfeuer): I've started a [https://ghc.haskell.org/trac/ghc/wiki/NewtypeOptimizationForGADTS wiki page] to give examples of why we want this. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1965#comment:29> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9526: Add missing Generic instances in base
by GHC 25 May '16

25 May '16

#9526: Add missing Generic instances in base -------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: libraries/base | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Moderate (less | Type of failure: than a day) | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Most primitive types (`Int`, `Char`, etc.) have a GHC.Generics.Generic instance, but some are missing, such as `Integer` and the various `Word*` data types. We should consistently have instances for all primitive types offered by base, since they are required if you want to derive a Generic instance for any type that contains them. I boldly set the milestone to 7.10 because I naively assume this should be straightforward. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9526> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10512: Generic instances missing for Int32, Word64 etc.
by GHC 25 May '16

25 May '16

#10512: Generic instances missing for Int32, Word64 etc. -------------------------------------+------------------------------------- Reporter: | Owner: ekmett andreas.abel | Status: new Type: feature | Milestone: request | Version: 7.10.1 Priority: normal | Operating System: Unknown/Multiple Component: Core | Type of failure: None/Unknown Libraries | Blocked By: Keywords: | Related Tickets: Architecture: | Unknown/Multiple | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Some base types have Generic instances, like Integer, the machine-specific ones like Int32 have none. But these would be most useful when using generic Binary serialization. I think it makes sense to add Generic instances for *all* primitive types in base. I can define the instance myself, see https://github.com/agda/agda/commit/1d3710189989aced61be79c8e52945651fc94c0e {{{#!hs import GHC.Generics (Generic(..)) import qualified GHC.Generics as Gen data D_Int32 data C_Int32 instance Gen.Datatype D_Int32 where datatypeName _ = "Int32" moduleName _ = "GHC.Int32" -- packageName _ = "base" instance Gen.Constructor C_Int32 where conName _ = "" -- JPM: I'm not sure this is the right implementation... instance Generic Int32 where type Rep Int32 = Gen.D1 D_Int32 (Gen.C1 C_Int32 (Gen.S1 Gen.NoSelector (Gen.Rec0 Int32))) from x = Gen.M1 (Gen.M1 (Gen.M1 (Gen.K1 x))) to (Gen.M1 (Gen.M1 (Gen.M1 (Gen.K1 x)))) = x }}} However, as GHC.Generics is a moving target, and changes over the compiler versions, I'd rather not have to. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10512> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10623: Handling of ASCII encodings introduced in D898 breaks Unicode terminal detection
by GHC 24 May '16

24 May '16

#10623: Handling of ASCII encodings introduced in D898 breaks Unicode terminal detection -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2-rc2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: T8958a | Related Tickets: #10298, #7695 Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Phab:D898 was primarily intended to fix hangs in the event that `iconv` was unavailable (namely #10298 and #7695). In addition to this fix, it also introduced self-contained handling of ANSI terminals to allow compiled executables to run in minimal environments lacking iconv. However, the behavior that the patch introduced is highly suspicious. Specifically, it gives the user a UTF-8 encoding even if they requested ASCII. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10623> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12084: ghc --help suggests -auto-all instead of -fprof-auto
by GHC 24 May '16

24 May '16

#12084: ghc --help suggests -auto-all instead of -fprof-auto -------------------------------------+------------------------------------- Reporter: kjslag | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Documentation Unknown/Multiple | bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- 'ghc --help' suggests the use of -auto-all (see below), but according to [#r1 [1]], "-fprof-auto was known as -auto-all prior to GHC 7.4.1." I assume this means that GHC >= 7.4.1 should not mention -auto-all, and that -fprof-auto should be suggested instead. {{{ $ ghc --help ... -prof Compile for cost-centre profiling (add -auto-all for automagic cost-centres on all top-level functions) ... }}} [=#r1 [1]] https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/profiling.h… -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12084> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 24 May '16

24 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:"9d06ef1ae451a145607301dc7556931b537a7d83/ghc" 9d06ef1a/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="9d06ef1ae451a145607301dc7556931b537a7d83" Make Arrow desugaring deterministic This kills two instances of varSetElems that turned out to be nondeterministic. I've tried to untangle this before, but it's a bit hard with the fixDs in the middle. Fortunately I now have a test case that proves that we need determinism here. Test Plan: ./validate, new testcase Reviewers: simonpj, simonmar, austin, bgamari Reviewed By: bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2258 GHC Trac Issues: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:176> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 24 May '16

24 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:"4c6e69d58a300d6ef440d326a3fd29b58b284fa1/ghc" 4c6e69d5/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="4c6e69d58a300d6ef440d326a3fd29b58b284fa1" Document some benign nondeterminism I've changed the functions to their nonDet equivalents and explained why they're OK there. This allowed me to remove foldNameSet, foldVarEnv, foldVarEnv_Directly, foldVarSet and foldUFM_Directly. Test Plan: ./validate, there should be no change in behavior Reviewers: simonpj, simonmar, austin, goldfire, bgamari Reviewed By: bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2244 GHC Trac Issues: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:175> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11743: Add unicode support for special brackets (`{| |}` and `[| |]`)
by GHC 24 May '16

24 May '16

#11743: Add unicode support for special brackets (`{| |}` and `[| |]`) -------------------------------------+------------------------------------- Reporter: JoshPrice247 | Owner: JoshPrice247 Type: feature | Status: new request | Priority: low | Milestone: Component: Compiler | Version: 7.10.3 (Parser) | Keywords: unicode, | Operating System: Unknown/Multiple UnicodeSyntax | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: 2878, 10162 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This has been mentioned before but didn't have it's own ticket. The following where mentioned in #2978, but the respective patch did not include them: * For TemplateHaskell: `⟦ ⟧` (MATHEMATICAL _ WHITE SQUARE BRACKET) can be used instead of `[| |]` * For Generics: `⦃ ⦄` (_ WHITE CURLY BRACKET) can be used instead of `{| |}` * For Arrows: `⦇ ⦈` (Z NOTATION _ IMAGE BRACKET) can be used instead of `(| |)` Banana brackets were then suggested in #10162 and implemented in Phab:D2012 (which has been accepted, but has not yet landed). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11743> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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