September 2015 - ghc-tickets

[GHC] #8098: Faulty Word64 arithmetic if optimized
by GHC 02 Dec '15

02 Dec '15

#8098: Faulty Word64 arithmetic if optimized ----------------------------+--------------------------------- Reporter: achp | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.4.2 Keywords: | Operating System: Windows Architecture: x86 | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------+--------------------------------- The following program produces different results depending on optimization: Checked.hs: {{{ module Checked ((.-.)) where (.-.) :: (Bounded a, Integral a) => a -> a -> Maybe a x .-. y | x >= 0 && y < 0 = if z > x then Just z else Nothing | x >= 0 = if z <= x then Just z else Nothing | x < 0 && y > 0 = if z < x then Just z else Nothing | otherwise = Just z where z = x - y }}} Main.hs: {{{ module Main (main) where import Data.Maybe import Data.Word import Numeric import Checked main :: IO () main = print $ showHex (fromJust ((0xFFFFFFFF00000000 :: Word64) .-. 0x00000000FFFFFFFF)) "" }}} {{{ D:\dev\haskell\ch1>ghc --make Checked.hs Main.hs [1 of 2] Compiling Checked ( Checked.hs, Checked.o ) [2 of 2] Compiling Main ( Main.hs, Main.o ) Linking Main.exe ... D:\dev\haskell\ch1>Main.exe "fffffffe00000001" D:\dev\haskell\ch1>del *.hi *.o *.exe D:\dev\haskell\ch1>ghc --make -O2 Checked.hs Main.hs [1 of 2] Compiling Checked ( Checked.hs, Checked.o ) [2 of 2] Compiling Main ( Main.hs, Main.o ) Linking Main.exe ... D:\dev\haskell\ch1>Main.exe "fffe00000001" D:\dev\haskell\ch1> }}} The bug disappears if definition and usage of (.-.) are in the same module. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8098> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10896: BadSock triggers failing ASSERT
by GHC 01 Dec '15

01 Dec '15

#10896: BadSock triggers failing ASSERT -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 (Type checker) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- {{{ --- ./indexed-types/should_fail/BadSock.stderr.normalised 2015-09-18 20:44:48.437390831 +0000 +++ ./indexed-types/should_fail/BadSock.comp.stderr.normalised 2015-09-18 20:44:48.437390831 +0000 @@ -1,5 +1,5 @@ +ghc: panic! (the 'impossible' happened) + (GHC version 7.11.20150918 for x86_64-unknown-linux): + ASSERT failed! file compiler/typecheck/TcFlatten.hs, line 1041 -BadSock.hs:30:5: - The type family â€˜Readableâ€™ should have 1 argument, but has been given none - In the equations for closed type family â€˜Fooâ€™ - In the type family declaration for â€˜Fooâ€™ \ No newline at end of file +Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug \ No newline at end of file *** unexpected failure for BadSock(normal) }}} Haven't investigated any further. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10896> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10839: Consistent pretty-printing of type families
by GHC 01 Dec '15

01 Dec '15

#10839: Consistent pretty-printing of type families -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: task | Status: new Priority: lowest | Milestone: Component: Compiler | Version: 7.11 Keywords: newcomer | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- Say I have this silly open type family declaration: {{{#!hs type family F a type instance F a = a type instance F a = Int }}} GHC complains: {{{ Foo.hs:8:15: error: Conflicting family instance declarations: F a -- Defined at Foo.hs:8:15 F a -- Defined at Foo.hs:9:15 }}} Now let's do some silliness with a closed type family: {{{#!hs type family F a where F a = a F a = Int }}} GHC warns: {{{ T6018.hs:9:5: warning: Type family instance equation is overlapped: F a = Int }}} Finally, some silliness with a kind-polymorphic type family: {{{#!hs type family Gc (a :: k) (b :: k) = r | r -> k where Gc a b = Int }}} GHC complains: {{{ T6018.hs:9:5: error: Type family equation violates injectivity annotation. Injective kind variable ‘k’ is not inferable from the RHS type variables. In the RHS of type family equation: forall (k :: BOX) (a :: k) (b :: k). Gc a b = Int In the equations for closed type family ‘Gc’ In the type family declaration for ‘Gc’ }}} There are some inconsistencies in pprinting of type family equations: * for open type families we print the location where the equation was defined but we do not print the RHS * for closed type families we print the RHS but we do not print the location in the source file * kind-polymorphic equations are not indented I would like to have a consistent pretty-printing of type family equations, one that prints the RHS, source code location and indents kind- polymorphic equations. The difference in pretty printing between open and closed type families comes from the difference between pprinting `CoAxBranch` and `FamInst`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10839> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10836: Better error reporting for closed type families
by GHC 28 Nov '15

28 Nov '15

#10836: Better error reporting for closed type families -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect Unknown/Multiple | warning at compile-time Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- Consider this code: {{{#!hs {-# LANGUAGE TypeFamilies #-} module Bug where type family Foo a = r | r -> a type instance Foo Int = Int type instance Foo Bool = Int type family Bar a = r | r -> a type instance Bar Int = Int type instance Bar Bool = Int }}} Both definitions are incorrect as they violate their injectivity annotation. When I compile the module GHC reports errors on both definitons: {{{ Bug.hs:9:15: error: Type family equations violate injectivity annotation: Foo Bool = Int Foo Int = Int Bug.hs:13:15: error: Type family equations violate injectivity annotation: Bar Bool = Int Bar Int = Int }}} When I convert these to closed type families: {{{#!hs {-# LANGUAGE TypeFamilies #-} module Bug where type family Foo a = r | r -> a where Foo Int = Int Foo Bool = Int type family Bar a = r | r -> a where Bar Int = Int Bar Bool = Int }}} GHC only reports error on `Foo` but not on `Bar`: {{{ Bug.hs:8:5: error: Type family equations violate injectivity annotation: Foo Int = Int Foo Bool = Int In the equations for closed type family ‘Foo’ In the type family declaration for ‘Foo’ }}} Only when I fix the error on `Foo` I get the error on `Bar`. This is mostly annoying. A spectacular example of when this is really a problem can be seen in the testsuite: for open type families all the failing injectivity tests are in one test `T6018fail` but for closed type families there are twelve separate tests (`T6018closedfail01` through `T6018closedfail12`). I pinned down the problem to these lines in `TcTyClsDecls.tcTyClGroup`: {{{#!hs ; checkNoErrs $ mapM_ (recoverM (return ()) . checkValidTyCl) tyclss -- We recover, which allows us to report multiple validity errors -- the checkNoErrs is necessary to fix #7175. }}} As stated by the comment, removing `checkNoErrs` fixes the problem but breaks #7175. Commit message for d0ddde58f928a6b156d8061c406226c4fbb7cd22 suggests that this can't be easily fixed. Richard Eisenberg also remarks: "It's all about the irrefutable pattern in `rejigConRes` for matching up result types of GADTs." -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10836> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10755: Add `MonadPlus IO` and `Alternative IO` instances
by GHC 27 Nov '15

27 Nov '15

#10755: Add `MonadPlus IO` and `Alternative IO` instances -------------------------------------+------------------------------------- Reporter: hvr | Owner: Type: task | Status: new Priority: normal | Milestone: 7.12.1 Component: Core | Version: Libraries | Keywords: report- | Operating System: Unknown/Multiple impact | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- Cloned and adapted from #9588: ---- The following 2 instances are currently Orphans in `transformers` but shall be defined in `base` instead: {{{#!hs instance MonadPlus IO instance Alternative IO }}} This proposal by SPJ already passed the CLC back in April and only needs implementing. I'll submit a patch shortly to Phab ---- This needs coordination w/ Ross as `transformers` must not define the same instances for new enough `base` versions. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10755> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10279: panic on haskell-src-exts
by GHC 27 Nov '15

27 Nov '15

#10279: panic on haskell-src-exts -------------------------------------+------------------------------------- Reporter: | Owner: throwaway123 | Status: new Type: bug | Milestone: Priority: normal | Version: 7.10.1 Component: Compiler | Operating System: Linux Keywords: | Type of failure: Compile-time Architecture: x86_64 | crash (amd64) | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Compiling `Bug.hs`: {{{ {-# LANGUAGE QuasiQuotes #-} import Language.Haskell.Exts.QQ (dec) main :: IO () main = return () where foo = [dec| bar = 3 |] }}} by `ghc --make -v -dcore-lint Bug.hs` gives {{{ ghc --make -v -dcore-lint Bug.hs Glasgow Haskell Compiler, Version 7.10.1, stage 2 booted by GHC version 7.8.4 Using binary package database: /usr/lib/ghc-7.10.1/package.conf.d/package.cache wired-in package ghc-prim mapped to ghc- prim-0.4.0.0-7c945cc0c41d3b7b70f3edd125671166 wired-in package integer-gmp mapped to integer- gmp-1.0.0.0-3c947e5fb6dca14804d9b2793c521b67 wired-in package base mapped to base-4.8.0.0-1b689eb8d72c4d4cc88f445839c1f01a wired-in package rts mapped to builtin_rts wired-in package template-haskell mapped to template- haskell-2.10.0.0-e895139a0ffff267d412e3d0191ce93b wired-in package ghc mapped to ghc-7.10.1-325809317787a897b7a97d646ceaa3a3 wired-in package dph-seq not found. wired-in package dph-par not found. Hsc static flags: wired-in package ghc-prim mapped to ghc- prim-0.4.0.0-7c945cc0c41d3b7b70f3edd125671166 wired-in package integer-gmp mapped to integer- gmp-1.0.0.0-3c947e5fb6dca14804d9b2793c521b67 wired-in package base mapped to base-4.8.0.0-1b689eb8d72c4d4cc88f445839c1f01a wired-in package rts mapped to builtin_rts wired-in package template-haskell mapped to template- haskell-2.10.0.0-e895139a0ffff267d412e3d0191ce93b wired-in package ghc mapped to ghc-7.10.1-325809317787a897b7a97d646ceaa3a3 wired-in package dph-seq not found. wired-in package dph-par not found. *** Chasing dependencies: Chasing modules from: *Bug.hs Stable obj: [] Stable BCO: [] Ready for upsweep [NONREC ModSummary { ms_hs_date = 2015-04-09 10:01:43.312180074 UTC ms_mod = Main, ms_textual_imps = [import (implicit) Prelude, import Language.Haskell.Exts.QQ ( dec )] ms_srcimps = [] }] *** Deleting temp files: Deleting: compile: input file Bug.hs Created temporary directory: /tmp/ghc7356_0 *** Checking old interface for Main: [1 of 1] Compiling Main ( Bug.hs, Bug.o ) *** Parser: *** Renamer/typechecker: *** Simplify: *** CorePrep: *** ByteCodeGen: Loading package ghc-prim-0.4.0.0 ... linking ... done. *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/usr/lib/ghc-7.10.1/integ_2aU3IZNMF9a7mQ0OzsZ0dS --print-file-name libgmp.so Loading package integer-gmp-1.0.0.0 ... linking ... done. Loading package base-4.8.0.0 ... linking ... done. Loading package array-0.5.1.0 ... linking ... done. Loading package filepath-1.4.0.0 ... linking ... done. Loading package deepseq-1.4.1.1 ... linking ... done. Loading package time-1.5.0.1 ... linking ... done. Loading package bytestring-0.10.6.0 ... linking ... done. *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/usr/lib/ghc-7.10.1/unix_G4Yo1pNtYrk8nCq1cx8P9d --print-file-name librt.so *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/usr/lib/ghc-7.10.1/unix_G4Yo1pNtYrk8nCq1cx8P9d --print-file-name libutil.so *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/usr/lib/ghc-7.10.1/unix_G4Yo1pNtYrk8nCq1cx8P9d --print-file-name libdl.so *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/usr/lib/ghc-7.10.1/unix_G4Yo1pNtYrk8nCq1cx8P9d --print-file-name libpthread.so Loading package unix-2.7.1.0 ... linking ... done. Loading package directory-1.2.2.0 ... linking ... done. Loading package old-locale-1.0.0.7 ... linking ... done. Loading package old-time-1.1.0.3 ... linking ... done. Loading package text-1.2.0.4 ... linking ... done. Loading package polyparse-1.11 ... linking ... done. Loading package cpphs-1.19 ... linking ... done. Loading package pretty-1.1.2.0 ... linking ... done. Loading package haskell-src-exts-1.16.0.1 ... linking ... done. Loading package syb-0.4.4 ... linking ... done. Loading package template-haskell-2.10.0.0 ... linking ... done. Loading package transformers-0.4.2.0 ... linking ... done. Loading package mtl-2.2.1 ... linking ... done. Loading package nats-1 ... linking ... done. Loading package th-lift-0.7.2 ... linking ... done. Loading package containers-0.5.6.2 ... linking ... done. Loading package safe-0.3.8 ... linking ... done. Loading package th-expand-syns-0.3.0.6 ... linking ... done. Loading package th-reify-many-0.1.3 ... linking ... done. Loading package th-orphans-0.11.1 ... linking ... done. Loading package haskell-src-meta-0.6.0.9 ... linking ... done. Loading package haskell-src-exts-qq-0.6.1 ... linking ... done. Bug.hs:8:16:*** Deleting temp files: Deleting: /tmp/ghc7356_0/ghc7356_1.s Warning: deleting non-existent /tmp/ghc7356_0/ghc7356_1.s *** Deleting temp dirs: Deleting: /tmp/ghc7356_0 ghc: panic! (the 'impossible' happened) (GHC version 7.10.1 for x86_64-unknown-linux): qual_pkg haskell-src-exts-1.16.0.1 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} on my machine: {{{ $ uname -a Linux io 3.19.3-1-ARCH #1 SMP PREEMPT Thu Mar 26 14:56:16 CET 2015 x86_64 GNU/Linux $ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/lto- wrapper Target: x86_64-unknown-linux-gnu Configured with: /build/gcc/src/gcc-4.9-20150304/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared --enable-threads=posix --with-system-zlib --enable-__cxa_atexit --disable- libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object --enable-linker-build-id --enable-cloog-backend=isl --enable-lto --enable-plugin --enable-install- libiberty --with-linker-hash-style=gnu --disable-multilib --disable-werror --enable-checking=release Thread model: posix gcc version 4.9.2 20150304 (prerelease) (GCC) $ ghc-pkg list /usr/lib/ghc-7.10.1/package.conf.d Cabal-1.22.2.0 array-0.5.1.0 async-2.0.2 base-4.8.0.0 bin-package-db-0.0.0.0 binary-0.7.3.0 bytestring-0.10.6.0 containers-0.5.6.2 cpphs-1.19 deepseq-1.4.1.1 directory-1.2.2.0 filepath-1.4.0.0 ghc-7.10.1 ghc-paths-0.1.0.9 ghc-prim-0.4.0.0 haddock-api-2.16.0 haddock-library-1.2.0 haskeline-0.7.2.1 haskell-src-exts-1.16.0.1 haskell-src-exts-qq-0.6.1 haskell-src-meta-0.6.0.9 hoopl-3.10.0.2 hpc-0.6.0.2 integer-gmp-1.0.0.0 minisat-0.1.1 mtl-2.2.1 nats-1 old-locale-1.0.0.7 old-time-1.1.0.3 polyparse-1.11 pretty-1.1.2.0 process-1.2.3.0 rts-1.0 safe-0.3.8 satchmo-core-0.8.0 stm-2.4.4 syb-0.4.4 template-haskell-2.10.0.0 terminfo-0.4.0.1 text-1.2.0.4 th-expand-syns-0.3.0.6 th-lift-0.7.2 th-orphans-0.11.1 th-reify-many-0.1.3 time-1.5.0.1 transformers-0.4.2.0 unix-2.7.1.0 xhtml-3000.2.1 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10279> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10773: Add Control.Monad.IO.Class from transformers to base
by GHC 27 Nov '15

27 Nov '15

#10773: Add Control.Monad.IO.Class from transformers to base -------------------------------------+------------------------------------- Reporter: | Owner: ekmett RyanGlScott | Type: feature | Status: new request | Priority: normal | Milestone: Component: Core | Version: 7.10.2 Libraries | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- (As proposed in a Haskell libraries mailing list thread [https://mail.haskell.org/pipermail/libraries/2015-July/026008.html here]). This Trac issue addresses one of the two suggestions made in the proposal, i.e., moving `Control.Monad.IO.Class` from `transformers` to `base`. (The second, introducing a `MonadIO Q` instance in `template-haskell`, can be dealt with depending on the result of this.) Conceptually, this change is very similar in spirit to #9664—the `MonadIO` class is a Haskell98 typeclass that has proven to be widely useful in abstracting `IO`-based functions into a type signature that can be used with monad transformer stacks. Moving `MonadIO`'s module into `base` would allow more widespread use without incurring a `transformers` dependency, and it could provide a first step for generalizing more `base` functions from `IO` to `MonadIO`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10773> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10394: LLVM mangler doesn't mangle AVX instructions
by GHC 27 Nov '15

27 Nov '15

#10394: LLVM mangler doesn't mangle AVX instructions -------------------------------------+------------------------------------- Reporter: dobenour | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.11 (LLVM) | Operating System: Unknown/Multiple Keywords: | Type of failure: Runtime crash Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- The LLVM mangler does not currently transform AVX instructions on x86-64 platforms, due to a missing #include. Also, it is significantly more complicated than necessary, due to the file into sections (not needed anymore), and is sensitive to the details of the whitespace in the assembly. I have attached a modified mangler that I believe to be simpler and more robust. I have not tested it, though, as I do not have a recent enough version of LLVM on my machine. I am marking this as `Runtime crash' because that is what would happen if the unchanged AVX instructions made their way into the executable. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10394> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10483: Refactor HsForAllTy
by GHC 24 Nov '15

24 Nov '15

#10483: Refactor HsForAllTy -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- I got sucked into refactoring `HsForAllTy`, like this: {{{ data HsType name = HsForAllTy (HsForAll name) (LHsType name) | ... data HsForAll name -- The quantifiers of a HsForAllTy = HSF { hsf_flag :: HsExplicitFlag , hsf_extra :: Maybe SrcSpan , hsf_qtvs :: LHsTyVarBndrs name , hsf_ctxt :: LHsContext name } }}} This makes a number of functions neater, as well as naming the fields of a troublesomely-high-arity data constructor. This ticket is here to track progress. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10483> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10656: Ability to get stack traces from Haskell code
by GHC 23 Nov '15

23 Nov '15

#10656: Ability to get stack traces from Haskell code -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Tarrasch Type: feature | Status: new request | Milestone: 7.12.1 Priority: normal | Version: 7.10.1 Component: Compiler | Operating System: Unknown/Multiple Keywords: | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: #3693 Test Case: | Blocking: | Differential Revisions: Phab:D963 | -------------------------------------+------------------------------------- With the merge of Phab:D169 and Phab:D396 (included in GHC 7.10.1) GHC now has the ability to produce DWARF debugging information in compiled binaries. It would be nice if Haskell programs could request stack backtraces from the RTS. Tarrasch has some work in this direction in Phab:D963 however there are a number of questions that remain outstanding, * do we want to rely on an external library for parsing DWARF information? If so, how do we address portability concerns? * What should the Haskell-land interfaces look like? Writing down some concrete use-cases would help here. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10656> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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