March 2018 - ghc-tickets

[GHC] #14170: 8.2.1 regression: GHC fails to simplify `natVal`
by GHC 16 Jun '18

16 Jun '18

#14170: 8.2.1 regression: GHC fails to simplify `natVal` -------------------------------------+------------------------------------- Reporter: vagarenko | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.2.1 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: -------------------------------------+------------------------------------- When GHC 8.2.1 compiles this code with `-O`: {{{#!hs {-# LANGUAGE TypeApplications #-} {-# LANGUAGE TypeInType #-} module NatVal where import Data.Proxy import GHC.TypeLits foo = natVal $ Proxy @0 }}} it produces the following Core: {{{#!hs -- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0} NatVal.foo1 :: Integer NatVal.foo1 = 0 -- RHS size: {terms: 41, types: 18, coercions: 0, joins: 0/0} foo :: Integer foo = case NatVal.foo1 of wild_a1iV { integer-gmp-1.0.1.0:GHC.Integer.Type.S# i#_a2ke -> case GHC.Prim.tagToEnum# @ Bool (GHC.Prim.>=# i#_a2ke 0#) of { False -> case GHC.Natural.underflowError of wild2_00 { }; True -> integer-gmp-1.0.1.0:GHC.Integer.Type.wordToInteger (GHC.Prim.int2Word# i#_a2ke) }; integer-gmp-1.0.1.0:GHC.Integer.Type.Jp# dt_a2km -> case GHC.Prim.uncheckedIShiftRL# (GHC.Prim.sizeofByteArray# dt_a2km) 3# of { __DEFAULT -> case GHC.Prim.sizeofByteArray# dt_a2km of { __DEFAULT -> wild_a1iV; 0# -> case GHC.Natural.underflowError of wild4_00 { } }; 1# -> case GHC.Prim.indexWordArray# dt_a2km 0# of wild2_a2kq { __DEFAULT -> integer-gmp-1.0.1.0:GHC.Integer.Type.wordToInteger wild2_a2kq } }; integer-gmp-1.0.1.0:GHC.Integer.Type.Jn# ipv_a2kt -> case GHC.Natural.underflowError of wild1_00 { } } }}} while GHC-8.0.1 does the right thing: {{{#!hs -- RHS size: {terms: 1, types: 0, coercions: 0} foo :: Integer foo = 0 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14170> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13833: Instances with GHC.TypeLits.Nat/Symbol should be possible without FlexibleInstances.
by GHC 15 Jun '18

15 Jun '18

#13833: Instances with GHC.TypeLits.Nat/Symbol should be possible without FlexibleInstances. -------------------------------------+------------------------------------- Reporter: Hjulle | Owner: (none) Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 8.0.2 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: -------------------------------------+------------------------------------- Yes I know, `0` and `"B"` are not technically type constructors, but it's as close as you can get for the kinds Nat and Symbol. Test cases: {{{#!hs {-# LANGUAGE DataKinds, KindSignatures #-} import GHC.TypeLits (Nat, Symbol) class A (n::Nat) instance A 0 class B (s::Symbol) instance B "B" }}} Result: {{{ A.hs:6:10: error: • Illegal instance declaration for ‘A 0’ (All instance types must be of the form (T a1 ... an) where a1 ... an are *distinct type variables*, and each type variable appears at most once in the instance head. Use FlexibleInstances if you want to disable this.) • In the instance declaration for ‘A 0’ A.hs:9:10: error: • Illegal instance declaration for ‘B "B"’ (All instance types must be of the form (T a1 ... an) where a1 ... an are *distinct type variables*, and each type variable appears at most once in the instance head. Use FlexibleInstances if you want to disable this.) • In the instance declaration for ‘B "B"’ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13833> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14747: DisambiguateRecordFields fails for PatternSynonyms
by GHC 15 Jun '18

15 Jun '18

#14747: DisambiguateRecordFields fails for PatternSynonyms -------------------------------------+------------------------------------- Reporter: adamgundry | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 (Type checker) | Keywords: | Operating System: Unknown/Multiple PatternSynonyms | Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: #11283 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Consider: {{{#!hs {-# LANGUAGE PatternSynonyms #-} module A where pattern S{x} = [x] }}} {{{#!hs {-# LANGUAGE PatternSynonyms, DisambiguateRecordFields #-} module B where import A pattern T{x} = [x] e = S { x = 42 } }}} Compiling module B fails with `Ambiguous occurrence ‘x’` in the definition of `e`. In principle, `DisambiguateRecordFields` should select the field belonging to the `S` "data constructor". However, the current implementation of this works by identifying the parent type constructor, which doesn't exist for a pattern synonym. This continues to fail if `T` is replaced by a data type with a field `x`. If `S` is replaced by a data type, however, it starts working. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14747> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13900: Core lint in BuildFlavour=perf-llvm
by GHC 15 Jun '18

15 Jun '18

#13900: Core lint in BuildFlavour=perf-llvm -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 8.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I found the following Core lint failure when compiling c9977385dca9536f18374242f713b1048a38dec5 with `BuildFlavour=perf-llvm`, {{{ "inplace/bin/ghc-stage1" -hisuf dyn_hi -osuf dyn_o -hcsuf dyn_hc -fPIC -dynamic -O -H64m -fllvm -Wall -hide-all-packages -i -ighc/. -ighc/stage2/build -Ighc/stage2/build -ighc/stage2/build/ghc/autogen -Ighc/stage2/build/ghc/autogen -optP-DGHCI -optP-include -optPghc/stage2/build/ghc/autogen/cabal_macros.h -package-id base-4.10.0.0 -package-id array-0.5.1.2 -package-id bytestring-0.10.8.2 -package-id directory-1.3.0.2 -package-id process-1.6.0.0 -package-id filepath-1.4.1.2 -package-id ghc-boot-8.3 -package-id ghc-8.3 -package-id unix-2.7.2.2 -package-id containers-0.5.10.2 -package-id deepseq-1.4.3.0 -package-id ghci-8.3 -package-id haskeline-0.7.4.0 -package-id time-1.8.0.1 -package- id transformers-0.5.2.0 -Wall -fno-warn-name-shadowing -XHaskell2010 -O2 -dcore-lint -dcmm-lint -no-hs-main -threaded -no-user-package-db -rtsopts -Wnoncanonical-monad-instances -odir ghc/stage2/build -hidir ghc/stage2/build -stubdir ghc/stage2/build -c ghc/./GHCi/UI/Tags.hs -o ghc/stage2/build/GHCi/UI/Tags.dyn_o *** Core Lint errors : in result of Simplifier *** <no location info>: warning: [RHS of $wgo_XtpE :: [Name] -> Session -> State# RealWorld -> (# State# RealWorld, [[TagInfo]] #)] Rule "SC:$wgo0": lhs type: (# State# RealWorld, [[TagInfo]] #) rhs type: (# State# RealWorld, [Maybe TyThing] #) *** Offending Program *** (see attached) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13900> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14600: Work out why Hadrian builds routinely fail
by GHC 15 Jun '18

15 Jun '18

#14600: Work out why Hadrian builds routinely fail -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: bug | Status: new Priority: normal | Milestone: Component: Continuous | Version: 8.2.1 Integration | 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: -------------------------------------+------------------------------------- Currently Hadrian builds inexplicably and non-deterministically fail on CircleCI. They fail with, {{{ | Copy file (untracked): _build/stage1/libffi/inst/lib/libffi.a => _build/stage1/rts/libCffi_l.a | Copy file (untracked): _build/stage1/libffi/inst/lib/libffi.a => _build/stage1/rts/libCffi_debug.a | Copy file (untracked): _build/stage1/libffi/inst/lib/libffi.a => _build/stage1/rts/libCffi_thr.a | Copy file (untracked): _build/stage1/libffi/inst/lib/libffi.a => _build/stage1/rts/libCffi_thr_debug.a | Copy file (untracked): _build/stage1/libffi/inst/lib/libffi.a => _build/stage1/rts/libCffi_thr_l.a | Copy file (untracked): _build/stage1/libffi/inst/lib/libffi.a => _build/stage1/rts/libCffi_thr_p.a | Copy file (untracked): _build/stage1/libffi/inst/lib/libffi.a => _build/stage1/rts/libCffidebug_-ghc8.5.20171218.so | Copy file (untracked): _build/stage1/libffi/inst/lib/libffi.a => _build/stage1/rts/libCffithr_-ghc8.5.20171218.so | Copy file (untracked): _build/stage1/libffi/inst/lib/libffi.a => _build/stage1/rts/libCffithr_debug_-ghc8.5.20171218.so | Copy file (untracked): _build/stage1/libffi/inst/lib/libffi.a => _build/stage1/rts/libCffil_-ghc8.5.20171218.so | Copy file (untracked): _build/stage1/libffi/inst/lib/libffi.a => _build/stage1/rts/libCffithr_l_-ghc8.5.20171218.so | Successfully built custom library 'libffi' Too long with no output (exceeded 10m0s) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14600> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14601: Remove uses of unsafeGlobalDynFlags for -fopt-coercions
by GHC 14 Jun '18

14 Jun '18

#14601: Remove uses of unsafeGlobalDynFlags for -fopt-coercions -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 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: -------------------------------------+------------------------------------- Currently the `-fopt-coercions` flag finds its way to `OptCoercion.optCoercion` by way of the terrible `unsafeGlobalDynFlags`. In general it's nice to minimize the uses of `unsafeGlobalDynFlags`. However, it's not entirely clear that passing a `DynFlags` to `optCoercion` is worthwhile in this case as `-fopt-coercion` is essentially a debug flag. Leaving this here for later consideration. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14601> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14392: `make binary-dist` is broken
by GHC 14 Jun '18

14 Jun '18

#14392: `make binary-dist` is broken -------------------------------------+------------------------------------- Reporter: Fuuzetsu | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: 8.3 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: -------------------------------------+------------------------------------- If we run {{{#!bash ./boot ./configure make make binary-dist }}} We are soon greeted with the following error {{{ cd bindistprep && "/bin/tar" hcf - -T ../bindist-list.uniq | /usr/bin/xz -c > ../bindistprep/ghc-8.3.20171025-x86_64-unknown-linux.tar.xz /bin/tar: ghc-8.3.20171025/testsuite/utils/check-api-annotations/dist- install/build/.depend.c_asm: Cannot stat: No such file or directory /bin/tar: ghc-8.3.20171025/testsuite/utils/check-api-annotations/dist- install/build/.depend.haskell: Cannot stat: No such file or directory /bin/tar: ghc-8.3.20171025/testsuite/utils/check-api-annotations/dist- install/package-data.mk: Cannot stat: No such file or directory /bin/tar: ghc-8.3.20171025/testsuite/utils/check-api-annotations/ghc.mk: Cannot stat: No such file or directory /bin/tar: ghc-8.3.20171025/testsuite/utils/check-ppr/dist- install/build/.depend.c_asm: Cannot stat: No such file or directory /bin/tar: ghc-8.3.20171025/testsuite/utils/check-ppr/dist- install/build/.depend.haskell: Cannot stat: No such file or directory /bin/tar: ghc-8.3.20171025/testsuite/utils/check-ppr/dist-install/package- data.mk: Cannot stat: No such file or directory /bin/tar: ghc-8.3.20171025/testsuite/utils/check-ppr/ghc.mk: Cannot stat: No such file or directory /bin/tar: Exiting with failure status due to previous errors mv bindistprep/*.tar.xz "." }}} I suspect https://github.com/ghc/ghc/commit/1e9f90af7311c33de0f7f5b7dba594725596d675 is to blame: bindist was not updated. A temporary work around I'm using is {{{ + $(filter-out testsuite/utils/check-ppr/% testsuite/utils/check-api- annotations/% %/project.mk mk/config.mk %/mk/install.mk,$(MAKEFILE_LIST)) \ }}} in top level {{{ghc.mk}}} in {{{bindist-list}}} {{{eval}}} section. I have reported this in #ghc to Ben but I am creating this ticket such that we can track the progress. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14392> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14492: Tiered memory allocation restricts available memory
by GHC 14 Jun '18

14 Jun '18

#14492: Tiered memory allocation restricts available memory -------------------------------------+------------------------------------- Reporter: unode | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Runtime | Version: 8.0.2 System | Keywords: memory ulimit | Operating System: Linux Architecture: x86_64 | Type of failure: Poor/confusing (amd64) | error message Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This was first noticed when running a binary produced with GHC 8.0.2 through a queueing system (Sun Grid Engine) that limits available memory by setting `ulimit -v`. When running with **unlimited** address space, the binary reserves 1TB of RAM and everything works as expected. When running with **limited** address space, reservation happens in powers of 2 leading to significant unused memory at higher memory values. The tests are summarized in the following table: {{{ Limit VIRT Unused (all in GB) 8 4 8 10 8 2 16 8 8 32 16 16 34 32 2 64 32 32 66 64 2 128 64 64 130 128 2 256 128 128 258 256 2 512 256 256 514 512 2 1024 512 512 }}} In the last line, setting `ulimit -v` to 1024GB (1073741824) causes the binary to only be able to reserve 512GB. If at runtime the software needs more than 512GB it will abort with "out of memory" instead of expanding to as close to the specified ulimit as possible. PS: Is there any way to make the "out of memory" error a little bit more informative? Something that informs the user of how much memory was already being used and how much more was going to be reserved when the failure was seen? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14492> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11259: Use system runtime linker in GHCi on PowerPC 64 bit
by GHC 14 Jun '18

14 Jun '18

#11259: Use system runtime linker in GHCi on PowerPC 64 bit -------------------------------------+------------------------------------- Reporter: trommler | Owner: trommler Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: GHCi | Version: 7.11 Keywords: | Operating System: Linux Architecture: powerpc64 | Type of failure: GHCi crash Test Case: ghcilink004, | Blocked By: prog001, and 11 more | Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Teach GHCi to use the system runtime linker to load Haskell libraries on powerpc64. See the following test failures. ghcilink004: {{{ ghc-stage2: dir004/libfoo.a: unknown architecture (e_machine == 21) ghc-stage2: panic! (the 'impossible' happened) (GHC version 7.11.20151219 for powerpc64-unknown-linux): loadArchive "dir004/libfoo.a": failed CallStack (from ImplicitParams): error, called at libraries/ghci/GHCi/ObjLink.hs:91:21 in ghci-0.0:GHCi.ObjLink Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} prog001: {{{ ghc-iserv.bin: /home/peter/ghc/libraries/ghc-prim/dist-install/build /libHSghc-prim-0.5.0.0.a: unknown architecture (e_machine == 21) ghc-iserv.bin: loadArchive "/home/peter/ghc/libraries/ghc-prim/dist- install/build/libHSghc-prim-0.5.0.0.a": failed CallStack (from ImplicitParams): error, called at libraries/ghci/GHCi/ObjLink.hs:91:21 in ghci-0.0:GHCi.ObjLink ghc-stage2: ghc-iserv terminated (1) }}} Using the system runtime linker fixes 13 failing tests. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11259> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13634: num009 fails on POWER8
by GHC 14 Jun '18

14 Jun '18

#13634: num009 fails on POWER8 -------------------------------------+------------------------------------- Reporter: trommler | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: | Version: 8.1 libraries/base | Keywords: | Operating System: Linux Architecture: powerpc64 | Type of failure: Incorrect result Test Case: | at runtime libraries/base/tests/Numeric/num009| Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This failure is produced on a POWER8 running openSUSE Leap 42.2 for powerpc64le: {{{ +uh oh! tanf 1.5707964 +-2.2877334e7 +-2.2877332e7 +(-11438667,1) +(-11438666,1) Done }}} The test passes on a PowerPC 970MP (PowerMac G5) running openSUSE 13.2 powerpc64 (big endian). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13634> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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