September 2014 - ghc-tickets

[GHC] #9641: Point-free do block gives missing instance error
by GHC 28 Sep '14

28 Sep '14

#9641: Point-free do block gives missing instance error -------------------------------------+------------------------------------- Reporter: rasfar | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Documentation | Version: 7.8.1 Keywords: plugins | Operating System: Linux HasDynFlags | Type of failure: Architecture: x86 | Documentation bug Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- https://www.haskell.org/ghc/docs/latest/html/users_guide/compiler- plugins.html#manipulating-bindings This API example won't compile for me. {{{#!hs module SayNames.Plugin (plugin) where import GhcPlugins plugin :: Plugin plugin = defaultPlugin { installCoreToDos = install } install :: [CommandLineOption] -> [CoreToDo] -> CoreM [CoreToDo] install _ todo = do reinitializeGlobals return (CoreDoPluginPass "Say name" pass : todo) pass :: ModGuts -> CoreM ModGuts pass = do dflags <- getDynFlags bindsOnlyPass (mapM (printBind dflags)) where printBind :: DynFlags -> CoreBind -> CoreM CoreBind printBind dflags bndr@(NonRec b _) = do putMsgS $ "Non-recursive binding named " ++ showSDoc dflags (ppr b) return bndr printBind _ bndr = return bndr }}} Compiling (GHC 7.8.1, or 7.6.3). I get: {{{ SayNames/Plugin.hs:25:21: No instance for (HasDynFlags ((->) ModGuts)) arising from a use of ‘getDynFlags’ In a stmt of a 'do' block: dflags <- getDynFlags In the expression: do { dflags <- getDynFlags; bindsOnlyPass (mapM (printBind dflags)) } In an equation for ‘pass’: pass = do { dflags <- getDynFlags; bindsOnlyPass (mapM (printBind dflags)) } where printBind :: DynFlags -> CoreBind -> CoreM CoreBind printBind dflags bndr@(NonRec b _) = do { putMsgS $ "Non-recursive binding named " ++ showSDoc dflags (ppr b); .... } printBind _ bndr = return bndr }}} Changing to pointful style it compiles and works: {{{#!hs pass modguts = do dflags <- getDynFlags bindsOnlyPass (mapM (printBind dflags)) modguts }}} Maybe this is a compiler bug, actually? Dunno, I never use point-free style with monadic functions. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9641> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3242: ghci: can't load .so/.DLL for: m (addDLL: could not load DLL)
by GHC 28 Sep '14

28 Sep '14

#3242: ghci: can't load .so/.DLL for: m (addDLL: could not load DLL) ---------------------------------------+--------------------------- Reporter: jeffz1 | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.10.1 Component: GHCi | Version: 7.4.1 Resolution: | Keywords: Operating System: Windows | Architecture: x86 Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: 3658 Blocking: | Related Tickets: #7097 Differential Revisions: | ---------------------------------------+--------------------------- Changes (by oerjan): * cc: oerjan@… (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3242#comment:28> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3242: ghci: can't load .so/.DLL for: m (addDLL: could not load DLL)
by GHC 28 Sep '14

28 Sep '14

#3242: ghci: can't load .so/.DLL for: m (addDLL: could not load DLL) ---------------------------------------+--------------------------- Reporter: jeffz1 | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.10.1 Component: GHCi | Version: 7.4.1 Resolution: | Keywords: Operating System: Windows | Architecture: x86 Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: 3658 Blocking: | Related Tickets: #7097 Differential Revisions: | ---------------------------------------+--------------------------- Comment (by oerjan): I suspect I just hit this bug when trying to `cabal install random-extras` from Haskell Platform 2014.2.0.0 on Windows 8.1. The dependency `random- fu` uses the `logfloat` library from Template Haskell while compiling other modules, which gives me the error message: {{{ [ 7 of 29] Compiling Data.Random.Distribution.Uniform ( src\Data\Random\Distribu tion\Uniform.hs, dist\build\Data\Random\Distribution\Uniform.o ) Loading package ghc-prim ... linking ... done. [snipped long package list] Loading package logfloat-0.12.1 ... ghc.exe: m: Den angitte modulen ble ikke fun net. <command line>: can't load .so/.DLL for: m.dll (addDLL: could not load DLL) Failed to install random-fu-0.2.6.1 cabal: Error: some packages failed to install: random-extras-0.19 depends on random-fu-0.2.6.1 which failed to install. random-fu-0.2.6.1 failed during the building phase. The exception was: ExitFailure 1 }}} `logfloat.cabal` contains precisely such an `Extra-Libraries: m` line that is used in its default configuration. And trying to use `logfloat` from (Win)GHCi gives the same kind of error message. I am able to get around this for `logfloat` by giving `--flags -useFFI`, but I still think it's a shame if this bug prevents a straightforward cabal install from working. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3242#comment:27> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7682: Plugin example not updated for ghc 7.6
by GHC 28 Sep '14

28 Sep '14

#7682: Plugin example not updated for ghc 7.6 -------------------------------------+------------------------------------ Reporter: edsko | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Documentation | Version: 7.6.2 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by Reid Barton <rwbarton@…>): In [changeset:"071167c793489f4071c348223f9591d20dbe11a3/ghc"]: {{{ #!CommitTicketReference repository="ghc" revision="071167c793489f4071c348223f9591d20dbe11a3" User's Guide: Fix compiler plugin example (#9641, #7682) The previous fix was incorrectly eta-reduced. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7682#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9191: Semi-exported names
by GHC 27 Sep '14

27 Sep '14

#9191: Semi-exported names --------------------------------------+------------------------------------ Reporter: dfeuer | Owner: Type: feature request | Status: new Priority: low | Milestone: Component: Compiler (CodeGen) | Version: 7.8.2 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: --------------------------------------+------------------------------------ It's generally inadvisable to add exports to a well-known module because they may clash with existing code using the module and importing it in its entirety. As a work-around, I propose allowing a module to export a name that will only be visible in a module that lists it explicitly. Something approximately like module Foo (a, b, explicit c) simply import Foo would not bring c into scope, but import Foo (c) would bring in c (and nothing else). To get everything, we could use something like import Foo revealing (c) and to be a bit picky, import Foo hiding (a) revealing (c). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9191> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9515: Deprecate -XExplicitForAll
by GHC 27 Sep '14

27 Sep '14

#9515: Deprecate -XExplicitForAll -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- The problem is that it uses the same syntax as -XScopedTypeVariables to mean something a bit different, and incompatible. -XExplicitForAll is of rather limited utility, whereas -XScopedTypeVariables is a wonderful thing. Confusion is bad. {{{#!hs f :: forall a . a -> [a] f a = let g :: a -> a g x = x in g [a] }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9515> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9326: Minor change to list comprehension structure leads to poor performance
by GHC 27 Sep '14

27 Sep '14

#9326: Minor change to list comprehension structure leads to poor performance -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Keywords: | Differential Revisions: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------- According to [http://stackoverflow.com/questions/24690406/haskell-list- comprehension-speed-inconsistencies] ''and my own testing'', the code in compspeed.hs reliably runs several times faster than the code in compspeedslow.hs with ghc 7.8.3, although this apparently does not happen with 7.6.3. The basic distinction is between a list comprehension of the form {{{ [(a,h) | ..., let h = expr] }}} and {{{ [(a,expr) | ...] }}} The core produced by -ddump-simpl is completely different in each case, so I can't figure out what's going on. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9326> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7987: GHC Build Error
by GHC 27 Sep '14

27 Sep '14

#7987: GHC Build Error ----------------------------------------------+--------------------------- Reporter: singpolyma | Owner: Type: bug | Status: closed Priority: normal | Milestone: 7.10.1 Component: Compiler | Version: 7.7 Resolution: invalid | Keywords: Operating System: Unknown/Multiple | Architecture: x86 Type of failure: Building GHC failed | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | ----------------------------------------------+--------------------------- Comment (by rwbarton): I think this actually is fixed by 5fb72555f7b7ab67a33583f33ad9160761ca434f which I happened to come across today for unrelated reasons. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7987#comment:8> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7987: GHC Build Error
by GHC 27 Sep '14

27 Sep '14

#7987: GHC Build Error ----------------------------------------------+--------------------------- Reporter: singpolyma | Owner: Type: bug | Status: closed Priority: normal | Milestone: 7.10.1 Component: Compiler | Version: 7.7 Resolution: invalid | Keywords: Operating System: Unknown/Multiple | Architecture: x86 Type of failure: Building GHC failed | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | ----------------------------------------------+--------------------------- Changes (by singpolyma): * status: infoneeded => closed * resolution: => invalid Comment: Not sure if it's still present, and I worked around it for what I was doing at the time, so this can be closed, I think. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7987#comment:7> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1405: Make ghc (stage1) be compilable by non-GHC
by GHC 27 Sep '14

27 Sep '14

#1405: Make ghc (stage1) be compilable by non-GHC -------------------------------------+------------------------------------- Reporter: Isaac | Owner: Dupree | Status: new Type: task | Milestone: ⊥ Priority: normal | Version: 6.6.1 Component: Compiler | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: | Related Tickets: None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by thomie): In [changeset:"206b4dec78250efef3cd927d64dc6cbc54a16c3d/ghc"]: {{{ #!CommitTicketReference repository="ghc" revision="206b4dec78250efef3cd927d64dc6cbc54a16c3d" }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1405#comment:19> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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