January 2013 - ghc-tickets

Re: [GHC] #2247: GHC accepts FD violations, unless the conflicing instances are used
by GHC 13 Jan '13

13 Jan '13

#2247: GHC accepts FD violations, unless the conflicing instances are used --------------------------------------+------------------------------------- Reporter: claus | Owner: Type: bug | Status: new Priority: normal | Milestone: _|_ Component: Compiler (Type checker) | Version: 6.9 Resolution: | Keywords: TF vs FD Os: Unknown/Multiple | Architecture: Unknown/Multiple Difficulty: Unknown | Testcase: --------------------------------------+------------------------------------- Comment(by iavor.diatchki@…): commit fe61599ffebb27924c4beef47b6237542644f3f4 {{{ Author: Iavor S. Diatchki <iavor.diatchki(a)gmail.com> Date: Sun Jan 13 16:29:10 2013 -0800 Use a version of the coverage condition even with UndecidableInstances. This fixes bug #1241 and #2247. When UndecidableInstances are on, we use the "Liberal Coverage Condition", which is what GHC used to do in the past. This is the gist of the check: class C a b | a -> b instance theta => C t1 t2 we check that `fvs t2` is a subset of `fd-closure(theta,fvs t1)`. This is strictly more general than the coverage condition, while it still guarantees consistency with the FDs of the class. This check is completely orthogonal to termination (it by no means guarantees it). I am not sure of the role of the "coverage condition" in termination--- the comments suggest that it is important. This is why, for the moment, we only use this check when UndecidableInstances are on. compiler/typecheck/TcValidity.lhs | 8 ++++- compiler/types/FunDeps.lhs | 65 ++++++++++++++++++++++++++++++++++++- 2 files changed, 71 insertions(+), 2 deletions(-) }}} -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2247#comment:7> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1241: Functional dependency Coverage Condition is lifted, and should not be
by GHC 13 Jan '13

13 Jan '13

#1241: Functional dependency Coverage Condition is lifted, and should not be ----------------------------------------+----------------------------------- Reporter: guest | Owner: Type: bug | Status: new Priority: normal | Milestone: _|_ Component: Compiler (Type checker) | Version: 6.6 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Difficulty: Unknown Testcase: | ----------------------------------------+----------------------------------- Comment(by iavor.diatchki@…): commit fe61599ffebb27924c4beef47b6237542644f3f4 {{{ Author: Iavor S. Diatchki <iavor.diatchki(a)gmail.com> Date: Sun Jan 13 16:29:10 2013 -0800 Use a version of the coverage condition even with UndecidableInstances. This fixes bug #1241 and #2247. When UndecidableInstances are on, we use the "Liberal Coverage Condition", which is what GHC used to do in the past. This is the gist of the check: class C a b | a -> b instance theta => C t1 t2 we check that `fvs t2` is a subset of `fd-closure(theta,fvs t1)`. This is strictly more general than the coverage condition, while it still guarantees consistency with the FDs of the class. This check is completely orthogonal to termination (it by no means guarantees it). I am not sure of the role of the "coverage condition" in termination--- the comments suggest that it is important. This is why, for the moment, we only use this check when UndecidableInstances are on. compiler/typecheck/TcValidity.lhs | 8 ++++- compiler/types/FunDeps.lhs | 65 ++++++++++++++++++++++++++++++++++++- 2 files changed, 71 insertions(+), 2 deletions(-) }}} -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1241#comment:20> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7542: GHC doesn't optimize (strict) composition with id
by GHC 13 Jan '13

13 Jan '13

#7542: GHC doesn't optimize (strict) composition with id ---------------------------------+------------------------------------------ Reporter: shachaf | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.1 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: Runtime performance bug Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | ---------------------------------+------------------------------------------ Changes (by ekmett): * cc: ekmett@… (added) -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7542#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #849: Offer control over branch prediction
by GHC 13 Jan '13

13 Jan '13

#849: Offer control over branch prediction ---------------------------------+------------------------------------------ Reporter: simonpj | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.6.2 Component: Compiler | Version: 6.4.2 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: None/Unknown Difficulty: Unknown | Testcase: N/A Blockedby: | Blocking: Related: | ---------------------------------+------------------------------------------ Changes (by buecking): * cc: buecking@… (added) -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/849#comment:21> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3005: Normalize fully-applied type functions prior to display
by GHC 13 Jan '13

13 Jan '13

#3005: Normalize fully-applied type functions prior to display -------------------------------+-------------------------------------------- Reporter: dmcclean | Owner: chak Type: feature request | Status: closed Priority: lowest | Milestone: 7.6.2 Component: GHCi | Version: 6.10.1 Resolution: fixed | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Difficulty: Unknown Testcase: | Blockedby: Blocking: | Related: -------------------------------+-------------------------------------------- Changes (by monoidal): * status: new => closed * resolution: => fixed Comment: I believe this is fixed by the {{{:kind!}}} command. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3005#comment:13> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7372: Lint failure in GHC 7.6.1
by GHC 13 Jan '13

13 Jan '13

#7372: Lint failure in GHC 7.6.1 -------------------------------+-------------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: closed Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.6.1 Resolution: fixed | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Difficulty: Unknown Testcase: | Blockedby: Blocking: | Related: -------------------------------+-------------------------------------------- Changes (by monoidal): * status: new => closed * resolution: => fixed Comment: I checked it. TL;DR: the same cause as in #7312, fixed in HEAD and STABLE. Here's a small version: {{{ module Main where data Exp = Cte Integer | Let Exp eval :: Exp -> (->) a Integer eval (Cte i) = return i -- (1) eval (Let b) = \m -> eval b m -- (2) main = undefined }}} Under GHC 7.6.1, there are two problems. Both are fixed by changing (->) a Integer to a -> Integer. Line (1) compiles but fails dcore-lint. In fact {{{ c :: (->) a a c = id }}} already fails dcore-lint, saying that the types {{{(->) a a}}} and {{{a -> a}}} do not match. Line (2) gives panic identical to #7312. The code works fine after the fix in #7312. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7372#comment:2> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3333: GHCi doesn't load weak symbols
by GHC 13 Jan '13

13 Jan '13

#3333: GHCi doesn't load weak symbols --------------------------------------+------------------------------------- Reporter: heatsink | Owner: akio Type: bug | Status: patch Priority: normal | Milestone: 7.6.2 Component: GHCi | Version: 6.10.4 Keywords: weak, dynamic loading | Os: Linux Architecture: x86 | Failure: None/Unknown Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | --------------------------------------+------------------------------------- Comment(by akio): The patches validate together on my Linux machine. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3333#comment:22> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7534: allocateRegsAndSpill: Cannot read from uninitialized register
by GHC 13 Jan '13

13 Jan '13

#7534: allocateRegsAndSpill: Cannot read from uninitialized register --------------------------+------------------------------------------------- Reporter: erikd | Owner: simonmar Type: bug | Status: infoneeded Priority: normal | Milestone: Component: Compiler | Version: 7.7 Keywords: | Os: Linux Architecture: powerpc64 | Failure: Building GHC failed Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | --------------------------+------------------------------------------------- Comment(by PHO): Isn't this related to #7442? -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7534#comment:6> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2705: ghc discards version of wired-in packages
by GHC 12 Jan '13

12 Jan '13

#2705: ghc discards version of wired-in packages -------------------------------+-------------------------------------------- Reporter: thoughtpolice | Owner: Type: bug | Status: closed Priority: normal | Milestone: _|_ Component: Compiler | Version: 6.10.1 Resolution: wontfix | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Difficulty: Unknown Testcase: | Blockedby: Blocking: | Related: -------------------------------+-------------------------------------------- Changes (by thoughtpolice): * status: new => closed * failure: => None/Unknown * resolution: => wontfix Comment: This bug is old, will probably never be fixed and is a bad idea in hindsight. Closing. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2705#comment:9> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7216: Compositional blocking on file descriptors
by GHC 12 Jan '13

12 Jan '13

#7216: Compositional blocking on file descriptors -------------------------------+-------------------------------------------- Reporter: AndreasVoellmy | Owner: igloo Type: feature request | Status: closed Priority: normal | Milestone: 7.8.1 Component: libraries/base | Version: 7.4.2 Resolution: fixed | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Difficulty: Unknown Testcase: | Blockedby: Blocking: | Related: -------------------------------+-------------------------------------------- Changes (by igloo): * status: patch => closed * resolution: => fixed Comment: Applied, thanks! -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7216#comment:16> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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