June 2014 - ghc-tickets

Re: [GHC] #7730: :info and polykinds
by GHC 03 Jun '14

03 Jun '14

#7730: :info and polykinds --------------------------------------------+------------------------------ Reporter: monoidal | Owner: archblob Type: bug | Status: patch Priority: normal | Milestone: 7.10.1 Component: Compiler (Type checker) | Version: 7.6.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: #8776 --------------------------------------------+------------------------------ Comment (by simonpj): Well that was a struggle, but I finally pushed this through. You'd done the heavy lifting but there were some dark corners I had to peer into. Thanks for making this happen Simon -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7730#comment:52> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7730: :info and polykinds
by GHC 03 Jun '14

03 Jun '14

#7730: :info and polykinds --------------------------------------------+------------------------------ Reporter: monoidal | Owner: archblob Type: bug | Status: patch Priority: normal | Milestone: 7.10.1 Component: Compiler (Type checker) | Version: 7.6.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: #8776 --------------------------------------------+------------------------------ Comment (by Simon Peyton Jones <simonpj@…>): In [changeset:"b4856f9f4f0fb3db473901b247d3fa94a11c25a0/ghc"]: {{{ #!CommitTicketReference repository="ghc" revision="b4856f9f4f0fb3db473901b247d3fa94a11c25a0" Do pretty-printing of TyThings via IfaceDecl (Trac #7730) All the initial work on this was done fy 'archblob' (fcsernik(a)gmail.com) thank you! I reviewed the patch, started some tidying, up and then ended up in a huge swamp of changes, not all of which I can remember now. But: * To suppress kind arguments when we have -fno-print-explicit-kinds, - IfaceTyConApp argument types are in a tagged list IfaceTcArgs * To allow overloaded types to be printed with =>, add IfaceDFunTy to IfaceType. * When printing data/type family instances for the user, I've made them print out an informative RHS, which is a new feature. Thus ghci> info T data family T a data instance T Int = T1 Int Int data instance T Bool = T2 * In implementation terms, pprIfaceDecl has just one "context" argument, of type IfaceSyn.ShowSub, which says - How to print the binders of the decl see note [Printing IfaceDecl binders] in IfaceSyn - Which sub-comoponents (eg constructors) to print * Moved FastStringEnv from RnEnv to OccName It all took a ridiculously long time to do. But it's done! }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7730#comment:51> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7828: RebindableSyntax and Arrow
by GHC 03 Jun '14

03 Jun '14

#7828: RebindableSyntax and Arrow ----------------------------------------------+---------------------------- Reporter: AlessandroVermeulen | Owner: Type: bug | jstolarek Priority: normal | Status: new Component: Compiler (Type checker) | Milestone: 7.10.1 Resolution: | Version: 7.6.2 Operating System: Unknown/Multiple | Keywords: Type of failure: GHC rejects valid program | Architecture: Test Case: | Unknown/Multiple Blocking: | Difficulty: Unknown | Blocked By: | Related Tickets: ----------------------------------------------+---------------------------- Comment (by ross): Replying to [comment:12 jstolarek]: > After spending some time on this today I have to admit that arrow desugaring is still a mystery to me. For example this code: > > {{{ > proc n -> do > x <- returnA -< n > returnA -< x > }}} > > Is desugared to: > > {{{ > arr (\n -> (n, ())) >>> > arr (\ds -> case ds of { (ds2, ds3) -> ds2 }) >>> > arr (\ds -> ((ds, ()), ())) >>> > ((arr (\ds -> case ds of { (ds2, ds3) -> ds2 }) >>> id) *** id >>> > arr (\ds -> case ds of { (x, ds2) -> case ds2 of { () -> x } }) ) >>> > arr (\ds -> (ds, ())) >>> > arr (\ds -> case ds of { (ds2, ds3) -> ds2 }) >>> > id > }}} > This can be simplified to an identity (as expected), but GHC doesn't do it. This definitely seems like an opportunity for improvement. The simplifier reduces that to an identity using rules in Control.Arrow (though more rules are probably needed to handle slightly more complex cases). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7828#comment:14> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7828: RebindableSyntax and Arrow
by GHC 03 Jun '14

03 Jun '14

#7828: RebindableSyntax and Arrow ----------------------------------------------+---------------------------- Reporter: AlessandroVermeulen | Owner: Type: bug | jstolarek Priority: normal | Status: new Component: Compiler (Type checker) | Milestone: 7.10.1 Resolution: | Version: 7.6.2 Operating System: Unknown/Multiple | Keywords: Type of failure: GHC rejects valid program | Architecture: Test Case: | Unknown/Multiple Blocking: | Difficulty: Unknown | Blocked By: | Related Tickets: ----------------------------------------------+---------------------------- Comment (by ross): Replying to [comment:11 jstolarek]: > I have a few questions about implementation in `DsArrows` - I think these go to Ross. > > 1. What is the purpose of the stack created in the desugaring process? > 2. How do I read the notation describing each case of `dsCmd`? Eg. the `HsCmdApp` case has this comment: > > {{{ > -- D; ys |-a cmd : (t,stk) --> t' > -- D, xs |- exp :: t > -- ------------------------ > -- D; xs |-a cmd exp : stk --> t' > -- > -- ---> premap (\ ((xs),stk) -> ((ys),(e,stk))) cmd > }}} > What is `|-a`, `xs` and `ys`? What is the difference between `:` and `::`? Could you tell me how to read this particular comment? I should then be able to understand all the others. EDIT: Is there a semantic difference between `,` and `;` as in `D; ys` vs. `D, xs`? Yes, those differences in punctuation are significant. A type judgement for an expression (ignoring constraints) looks like {{{ D |- exp :: t }}} but one for a command looks like {{{ D; xs |-a cmd : stk --> t }}} Here * a is the type of arrow for this command * D is the environment of the surrounding proc expression * xs are variables defined within the proc expression, which will be inputs to the arrow * stk is a list of anonymous inputs to the arrow * t is the output type of the arrow So the translation of this command should be an expression with type {{{ D |- [[proc (xs) -> cmd]] : a ((xs),stk) t }}} In this particular rule, exp is typed using an ordinary expression judgement. It can use both external valuables (D) and those local to the proc expression (xs), so these are combined in a single environment. (Commands, in contrast, need to keep these separate.) The value of that expression is then pushed onto stk, which, together with xs, is input to cmd. (The lambda rule for commands lets you take a value from the stack and put it in the local environment, giving it a name.) The remaining wrinkle here is that cmd may not need all the variables in xs, but just the subset ys of xs, so the function inside the premap may also trim the environment from xs to ys. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7828#comment:13> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8768: Internal compiler error on haskell-src-exts 1.14.01 (profiling)
by GHC 03 Jun '14

03 Jun '14

#8768: Internal compiler error on haskell-src-exts 1.14.01 (profiling) ----------------------------------+--------------------------------------- Reporter: MagnusTherning | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.1-rc1 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: Compile-time crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+--------------------------------------- I'm configuring and building {{{haskell-src-exts}}} like this: {{{ runhaskell Setup configure -O -p --enable-shared \ -fbase4 runhaskell Setup build }}} It builds the ordinary bits just fine, but when it gets to compiling for profiling: {{{ [ 1 of 22] Compiling Language.Haskell.Exts.Annotated.Syntax ( src/Language/Haskell/Exts/Annotated/Syntax.hs, dist/build/Language/Haskell/Exts/Annotated/Syntax.p_o ) /tmp/ghc340_0/ghc340_8.s:1:0: internal compiler error: Segmentation fault .section .rodata ^ Please submit a full bug report, with preprocessed source if appropriate. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8768> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8475: Library docs: broken links to Foreign.ForeignPtr
by GHC 03 Jun '14

03 Jun '14

#8475: Library docs: broken links to Foreign.ForeignPtr ------------------------------------+------------------------------------- Reporter: simonmar | Owner: Type: bug | Status: new Priority: high | Milestone: 7.8.1 Component: Documentation | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- In the library docs at `http://www.haskell.org/ghc/docs/latest/html/libraries/index.html`, the `Foreign.ForeignPtr` module in the contents is the one from `haskell2010`, not `base`. This causes various problems, it seems. For instance: * the link from `ForeignPtr` to `Foreign.ForeignPtr` is broken * the link from `Foreign.Concurrent` to `Foreign.ForeignPtr` is broken there are probably other broken links too. We need to figure out what to do about overlapping modules properly. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8475> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8781: check if GNU nm is realy needed and if so let configure detect gnm
by GHC 03 Jun '14

03 Jun '14

#8781: check if GNU nm is realy needed and if so let configure detect gnm ----------------------------------+---------------------------------------- Reporter: maeder | Owner: Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.8.1-rc1 Component: Build System | Operating System: Solaris Keywords: | Type of failure: Building GHC failed Architecture: x86 | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | ----------------------------------+---------------------------------------- building ghc-7.8.20140130 under Solaris fails with a non-GNU nm as follows: {{{ inplace/bin/deriveConstants --gen-header -o includes/dist- derivedconstants/header/DerivedConstants.h --tmpdir includes/dist- derivedconstants/header/ --gcc-program "/opt/csw/bin/gcc" --gcc-flag -U__i686 --gcc-flag -fno-stack-protector --gcc-flag -Iincludes --gcc-flag -Iincludes/dist --gcc-flag -Iincludes/dist-derivedconstants/header --gcc- flag -Iincludes/dist-ghcconstants/header --gcc-flag -Irts --gcc-flag -fcommon --nm-program "/usr/ccs/bin/nm" Can't find "STD_HDR_SIZE" gmake[1]: *** [includes/dist-derivedconstants/header/DerivedConstants.h] }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8781> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8783: make ghc-pwd-bindist script /bin/sh compatible for Solaris
by GHC 03 Jun '14

03 Jun '14

#8783: make ghc-pwd-bindist script /bin/sh compatible for Solaris ------------------------------------+------------------------------------- Reporter: maeder | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: 7.8.1-rc1 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- http://www.haskell.org/ghc/dist/7.8.1-rc1/ghc-7.8.20140130-i386-unknown- solaris2.tar.bz2 has a ghc-pwd-bindist script containing {{{ #!/bin/sh export LD_LIBRARY_PATH="libraries/directory/dist- install/build:libraries/unix/dist-install/build:libraries/time/dist- install/build:libraries/old-locale/dist-install/build:libraries/filepath /dist-install/build:libraries/bytestring/dist- install/build:libraries/deepseq/dist-install/build:libraries/array/dist- install/build:libraries/base/dist-install/build:libraries/integer-gmp /dist-install/build:libraries/ghc-prim/dist- install/build:rts/dist/build:$LD_LIBRARY_PATH" exec "utils/ghc-pwd/dist-install/build/tmp/ghc-pwd" ${1+"$@"} }}} that fails during configure under Solaris with: {{{ checking for path to top of build tree... utils/ghc-pwd/dist- install/build/tmp/ghc-pwd-bindist: LD_LIBRARY_PATH=libraries/directory /dist-install/build:libraries/unix/dist-install/build:libraries/time/dist- install/build:libraries/old-locale/dist-install/build:libraries/filepath /dist-install/build:libraries/bytestring/dist- install/build:libraries/deepseq/dist-install/build:libraries/array/dist- install/build:libraries/base/dist-install/build:libraries/integer-gmp /dist-install/build:libraries/ghc-prim/dist-install/build:rts/dist/build:: is not an identifier configure: error: cannot determine current directory }}} see more under http://www.haskell.org/pipermail/glasgow-haskell- users/2014-February/024669.html -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8783> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9001: unexpected runtime crash
by GHC 03 Jun '14

03 Jun '14

#9001: unexpected runtime crash ------------------------------------+------------------------------------- Reporter: jwlato | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: Runtime crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Apologies for the poor summary, I'm not sure how to be more descriptive. I don't see anything dodgy here. Compiling the attached program `ghc -O -dcore-lint Test.hs` and running it results in a runtime crash. Various incarnations of this code have resulted in Test: internal error: scavenge_one: strange object 0 Test: internal error: stg_ap_p_ret and core dumps with no further information. I've been able to reproduce this with ghc-7.8.2 and ghc-7.6.3. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9001> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9021: rts/linker.c has a memory leak in the dlopen/dlerror code
by GHC 03 Jun '14

03 Jun '14

#9021: rts/linker.c has a memory leak in the dlopen/dlerror code -------------------------------------+------------------------------------- Reporter: hgolden | Owner: hgolden Type: bug | Status: new Priority: low | Milestone: 7.8.3 Component: Runtime System | Version: 7.8.2 Keywords: linker, memory | Operating System: POSIX leak | Type of failure: Runtime Architecture: Unknown/Multiple | performance bug Difficulty: Moderate (less | Test Case: than a day) | Blocking: Blocked By: | Related Tickets: | -------------------------------------+------------------------------------- The Coverity Scan of ghc highlighted a memory leak (CID 43168) in the internal_dlopen function in rts/linker.c. I wrote this code originally and I recall that there was a memory leak in certain situations, but I didn't fix it at the time because it seemed to be rather minor and only would occur in unusual cases. However, since Coverity identified it, I have thought about it and know how to fix the leak, so I am creating this ticket. The leak occurs because the error message from dlerror must be copied to allocated memory, since the dlerror message is not guaranteed to be stable, and its code is not guaranteed to be reentrant (see POSIX dlopen/dlerror documentation). As I originally coded Trac ticket #2615, I didn't bother to free the allocated memory. The fix is to make sure that the allocated memory is freed once the error message is displayed. Memory is only allocated if there is an error, so it must be freed only when an error has been identified and processed. As far as I know, this bug only exists on a POSIX system. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9021> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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