April 2016 - ghc-tickets

[GHC] #10382: Template Haskell quotes should work with stage 1 compiler
by GHC 18 Jun '16

18 Jun '16

#10382: Template Haskell quotes should work with stage 1 compiler -------------------------------------+------------------------------------- Reporter: ezyang | Owner: ezyang Type: feature | Status: new request | Milestone: 7.12.1 Priority: normal | Version: 7.11 Component: Template | Operating System: Unknown/Multiple Haskell | Type of failure: None/Unknown Keywords: | Blocked By: Architecture: | Related Tickets: Unknown/Multiple | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Right now, you must enable the `TemplateHaskell` extension to use quotes, and `TemplateHaskell` is not supported by the stage 1 compiler. But there actually is no good reason why this should be the case: quoting doesn't require any user-written code to be loaded up and run, so it should be doable by the stage 1 compiler. I propose adding a new extension, `Quotation`, which turns on JUST quotation and works with the stage 1 compiler. This will solve len's problem https://github.com/ekmett/lens/issues/496 where they want to rename some syntax using quotation, but don't want break compilation on a stage 1 compiler. See also #10279. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10382> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9525: +RTS -xc stack trace sometimes reported twice
by GHC 16 Jun '16

16 Jun '16

#9525: +RTS -xc stack trace sometimes reported twice -------------------------------------+------------------------------------- Reporter: osa1 | Owner: osa1 Type: bug | Status: new Priority: low | Milestone: Component: Runtime System | Version: 7.8.3 Keywords: profiling, stack | Operating System: trace, error | Unknown/Multiple Architecture: x86_64 (amd64) | Type of failure: Incorrect Difficulty: Unknown | result at runtime Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Not sure if really a bug but just wanted to show. If this is a bug I'm hoping to fix this myself but I may need some guidance. Stack trace reported by `+RTS -xc` is sometimes printed twice. This program reports it only once, as expected: {{{#!haskell f :: Int -> Int f = error "hello" main = print (f 20) }}} {{{ ➜ ghc_patch ./error +RTS -xc *** Exception (reporting due to +RTS -xc): (THUNK_1_0), stack trace: Main.f, called from Main.CAF --> evaluated by: Main.main, called from Main.CAF error: hello }}} But if I change it to this: {{{#!haskell f :: Int -> Int f x = let x = x + 20 in x main = print (f 20) }}} Stack trace is reported twice: {{{ ➜ ghc_patch ./error +RTS -xc *** Exception (reporting due to +RTS -xc): (THUNK_STATIC), stack trace: Main.f.x, called from Main.f, called from Main.main, called from Main.CAF *** Exception (reporting due to +RTS -xc): (THUNK_STATIC), stack trace: Main.f.x, called from Main.f, called from Main.main, called from Main.CAF error: <<loop>> }}} Can anyone confirm that this is really a bug? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9525> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8825: ghc can't determine gcc version on ru_RU locale
by GHC 14 Jun '16

14 Jun '16

#8825: ghc can't determine gcc version on ru_RU locale ------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | 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: | ------------------------------------+------------------------------------- Current ghc spits warnings time to time: {{{ <no location info>: Warning: Couldn't figure out linker information! Make sure you're using GNU gcc, or clang }}} It's because my default locale is '''LANG=ru_RU.UTF-8''' [1] {{{ ... gcc версия 4.8.2 (Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest) }}} versus '''LANG=C''' {{{ ... gcc version 4.8.2 (Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest) }}} [1]: {{{ $ gcc -v Используются внутренние спецификации. COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.2/gcc COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.8.2/lto-wrapper Целевая архитектура: x86_64-pc-linux-gnu Параметры конфигурации: /subvolumes/var_tmp/portage/sys- devel/gcc-4.8.2-r1/work/gcc-4.8.2/configure --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr --bindir=/usr/x86_64-pc-linux- gnu/gcc-bin/4.8.2 --includedir=/usr/lib/gcc/x86_64-pc-linux- gnu/4.8.2/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/info --with-gxx- include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4 --with- python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/python --enable- languages=c,c++,fortran --enable-obsolete --enable-secureplt --disable- werror --with-system-zlib --enable-nls --without-included-gettext --enable-checking=release --with-bugurl=https://bugs.gentoo.org/ --with- pkgversion='Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest' --enable- libstdcxx-time --enable-shared --enable-threads=posix --enable- __cxa_atexit --enable-clocale=gnu --enable-multilib --with-multilib- list=m32,m64 --disable-altivec --disable-fixed-point --enable-targets=all --disable-libgcj --enable-libgomp --disable-libmudflap --disable-libssp --enable-lto --without-cloog Модель многопоточности: posix gcc версия 4.8.2 (Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest) }}} [2]: While LANG=C output: {{{ $ LANG=C gcc -v Using built-in specs. COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.2/gcc COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.8.2/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: /subvolumes/var_tmp/portage/sys- devel/gcc-4.8.2-r1/work/gcc-4.8.2/configure --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr --bindir=/usr/x86_64-pc-linux- gnu/gcc-bin/4.8.2 --includedir=/usr/lib/gcc/x86_64-pc-linux- gnu/4.8.2/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/info --with-gxx- include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4 --with- python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/python --enable- languages=c,c++,fortran --enable-obsolete --enable-secureplt --disable- werror --with-system-zlib --enable-nls --without-included-gettext --enable-checking=release --with-bugurl=https://bugs.gentoo.org/ --with- pkgversion='Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest' --enable- libstdcxx-time --enable-shared --enable-threads=posix --enable- __cxa_atexit --enable-clocale=gnu --enable-multilib --with-multilib- list=m32,m64 --disable-altivec --disable-fixed-point --enable-targets=all --disable-libgcj --enable-libgomp --disable-libmudflap --disable-libssp --enable-lto --without-cloog Thread model: posix gcc version 4.8.2 (Gentoo 4.8.2-r1 p1.4-ssptest, pie-0.5.9-ssptest) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8825> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11659: configure --help incorrectly says --docdir is still unversioned by default
by GHC 14 Jun '16

14 Jun '16

#11659: configure --help incorrectly says --docdir is still unversioned by default -------------------------------------+------------------------------------- Reporter: juhpetersen | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: 8.0.1-rc1 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: -------------------------------------+------------------------------------- In ghc-8.0.1 it seems docdir is no longer unversioned (#11354) by default, however 'configure --help' still says the default value is unversioned. This is a bit confusing. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11659> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10117: Change the scheme for reporting redundant imports
by GHC 14 Jun '16

14 Jun '16

#10117: Change the scheme for reporting redundant imports -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.4 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- The current scheme for reporting redundant imports is given on the [wiki:Commentary/Compiler/UnusedImports unused imports page]. [wiki:Migration/7.10#GHCsaysTheimportof...isredundant The 7.10 migration page] describes a hack to avoid redundant-import warnings during migration, without using CPP. The hack works for {{{ module Foo (Int, Word, Monoid(..)) where import Data.Monoid import Data.Word import Prelude }}} (the hack is putting `import Prelude` at the bottom). To understand why, read the specification on the [wiki:Commentary/Compiler/UnusedImports unused imports page]. But it fails for {{{ module Foo (Int, Word, Monoid(..)) where import Data.Monoid (Monoid(..)) import Data.Word (Word) import Prelude }}} because the specification treats itemised imports like `import Data.Word(Word)` differently to "import all" imports. The question: '''is there alternative spec (vs the one on the [wiki:Commentary/Compiler/UnusedImports unused imports page]) that would support the behaviour desired here, without having other undesirable consequences?''' -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10117> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11700: pattern match bug
by GHC 13 Jun '16

13 Jun '16

#11700: pattern match bug -------------------------------------+------------------------------------- Reporter: TobyGoodwin | 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: https://github.com/TobyGoodwin | /odd-ghc-pattern-bug | Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- With some types built by persistent-template, I'm running into very odd behaviour. Attempting to pull apart a tuple in one go... {{{#!hs let (Entity museKey muse, Entity msgKey msg, Entity fldrKey fldr) = cluster }}} fails (or rather, attempting to use msg or fldr fails) with errors like {{{ Couldn't match expected type ‘Folder’ with actual type ‘Folder’ }}} But splitting the pattern up: {{{#!hs let (a, b, c) = cluster Entity museKey muse = a Entity msgKey msg = b Entity fldrKey fldr = c }}} everything works normally Complete test case here: https://github.com/TobyGoodwin/odd-ghc-pattern- bug -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11700> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11788: Enable Thin Library support for the Runtime linker on Windows.
by GHC 13 Jun '16

13 Jun '16

#11788: Enable Thin Library support for the Runtime linker on Windows. -------------------------------------+------------------------------------- Reporter: Phyx- | Owner: Phyx- Type: feature | Status: new request | Priority: normal | Milestone: 8.2.1 Component: Runtime | Version: 7.10.3 System (Linker) | Keywords: | Operating System: Windows Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The runtime linker currently has an `#ifdef` that removes support for AR's thin archives for Windows. This because all the code is based on `char*` and Windows would require `wchar_t`. Using the abstraction of `pathchar` this can be enabled for Windows and remove another `#ifdef` from the RTS. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11788> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11670: Can't infer type
by GHC 13 Jun '16

13 Jun '16

#11670: Can't infer type -------------------------------------+------------------------------------- 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: -------------------------------------+------------------------------------- {{{#!hs {-# LANGUAGE InstanceSigs, PartialTypeSignatures #-} import Foreign.C.Types import Foreign.Storable import Foreign.Ptr data CTimeval = MkCTimeval CLong CLong peek :: Ptr CTimeval -> IO CTimeval peek ptr = do s <- peekElemOff (castPtr ptr) 0 :: _ _ mus <- peekElemOff (castPtr ptr) 1 return (MkCTimeval s mus) }}} Fails with {{{ baldur@Loki:~$ ghci -ignore-dot-ghci /tmp/tLcV.hs GHCi, version 8.1.20160117: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( /tmp/tLcV.hs, interpreted ) /tmp/tLcV.hs:11:10: error: • No instance for (Storable t) Possible fix: add (Storable t) to the context of an expression type signature: IO t • In a stmt of a 'do' block: s <- peekElemOff (castPtr ptr) 0 :: _ _ In the expression: do { s <- peekElemOff (castPtr ptr) 0 :: _ _; mus <- peekElemOff (castPtr ptr) 1; return (MkCTimeval s mus) } In an equation for ‘peek’: peek ptr = do { s <- peekElemOff (castPtr ptr) 0 :: _ _; mus <- peekElemOff (castPtr ptr) 1; return (MkCTimeval s mus) } Failed, modules loaded: none. }}} while {{{#!hs {-# LANGUAGE InstanceSigs, PartialTypeSignatures #-} import Foreign.C.Types import Foreign.Storable import Foreign.Ptr data CTimeval = MkCTimeval CLong CLong peek :: Ptr CTimeval -> IO CTimeval peek ptr = do s <- peekElemOff (castPtr ptr) 0 :: _ CLong mus <- peekElemOff (castPtr ptr) 1 return (MkCTimeval s mus) }}} succeeds. Is this expected? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11670> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11638: referring to the existential type from a GADT pattern match with a type application
by GHC 12 Jun '16

12 Jun '16

#11638: referring to the existential type from a GADT pattern match with a type application -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.1 (Type checker) | Keywords: | Operating System: Unknown/Multiple TypeApplications | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #11387 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Currently I can define a GADT like {{{ data T where MkT :: forall a. (Num a, Show a) => T }}} but it's useless on two counts: * At a use of the constructor `MkT`, I can't specify what type `a` I want to pack dictionaries for. (In fact the declaration is an error unless either the constraints are defaultable (as in the case above) or AllowAmbiguousTypes is enabled.) * At a pattern match against `MkT`, I have no way to refer to the type for which dictionaries were packed. The solution is to add a field of type `Proxy a` (possibly strict/unpacked) or `Proxy# a` to `MkT`. But these options are all a bit verbose and each have minor drawbacks. I had hoped that TypeApplications would address the two points above directly. * At a use of the constructor `MkT`, specify the type with a type application `MkT @a`. This part works as of 90f35612f16ff9cb2466cc936f12e748402abb85. * At a pattern match against `MkT`, I would like to be able to match the type directly like this: {{{ f :: T -> String f t = case t of MkT @a -> show (0 :: a) }}} This is the feature request. Note that, while this may be stressful for the parser due to as-patterns, I don't think there is any actual ambiguity as long as (1) type applications only appear on constructors, not variables, and (2) all type applications appear before any value-level fields of the constructor. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11638> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11204: Recompilation checking stochastically broken on Darwin
by GHC 12 Jun '16

12 Jun '16

#11204: Recompilation checking stochastically broken on Darwin ----------------------------------------+---------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 7.11 Keywords: | Operating System: MacOS X Architecture: Unknown/Multiple | Type of failure: Other Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+---------------------------- The `retc001` test usually fails on Darwin. Unfortunately, it also sometimes passes. Failures look like this, {{{ =====> retc001(normal) 1 of 1 [0, 0, 0] cd . && $MAKE -s --no-print-directory retc001 </dev/null > retc001.run.stdout 2> retc001.run.stderr Actual stderr output differs from expected: --- ./retc001.stderr.normalised 2015-12-11 23:02:23.000000000 +0200 +++ ./retc001.run.stderr.normalised 2015-12-11 23:02:23.000000000 +0200 @@ -1,2 +0,0 @@ - -C.hs:3:11: Module ‘B’ does not export ‘foo’ \ No newline at end of file Actual stdout output differs from expected: --- ./retc001.stdout.normalised 2015-12-11 23:02:23.000000000 +0200 +++ ./retc001.run.stdout.normalised 2015-12-11 23:02:23.000000000 +0200 @@ -3,5 +3,3 @@ [3 of 3] Compiling Main ( C.hs, nothing ) Middle End -[2 of 3] Compiling B ( B.hs, nothing ) -[3 of 3] Compiling Main ( C.hs, nothing ) [B changed] \ No newline at end of file *** unexpected failure for retc001(normal) }}} I suspect the problem is mtime resolution as if I apply the following patch it almost always passes, {{{ diff --git a/testsuite/tests/driver/retc001/Makefile b/testsuite/tests/driver/retc001/Makefile index a3cf6eb..bb1eca8 100644 --- a/testsuite/tests/driver/retc001/Makefile +++ b/testsuite/tests/driver/retc001/Makefile @@ -20,5 +20,6 @@ retc001: clean echo 'Middle' '$(TEST_HC)' $(TEST_HC_OPTS_NO_RECOMP) -fno-code -fwrite-interface --make C.hs echo 'End' + sleep 1 cp B2.hs B.hs -'$(TEST_HC)' $(TEST_HC_OPTS_NO_RECOMP) -fno-code -fwrite- interface --make C.hs }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11204> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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