June 2018 - ghc-tickets

[GHC] #13471: segmentation fault by compiling GHC
by GHC 06 Jun '18

06 Jun '18

#13471: segmentation fault by compiling GHC -------------------------------------+------------------------------------- Reporter: vanto | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: 8.0.2 Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Building GHC (amd64) | failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Hi,\\ I tried to compile GHC on my computer.\\ by compiling GHC under Linux I got this error message.\\ {{{ compiler/ghc.mk:588: recipe for target 'compiler/stage2/build/DynFlags.o' failed make[1]: *** [compiler/stage2/build/DynFlags.o] segmentation fault Makefile:122: recipe for target 'install' failed make: *** [install] Error 2 }}} on my computer Linux runs on VirtualBox.\\ the problem is probably with my hardware but as I know nothing I tell you this issue.\\ {{{ ~/ghc/inplace/bin$ /ghc-stage1 --version The Glorious Glasgow Haskell Compilation System, version 8.3.20170322 }}} Hope this help\\ -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13471> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14713: GHCi doesn't load project.
by GHC 06 Jun '18

06 Jun '18

#14713: GHCi doesn't load project. -------------------------------------+------------------------------------- Reporter: recursion- | Owner: (none) ninja | Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 8.2.2 Keywords: | Operating System: Unknown/Multiple Architecture: x86_64 | Type of failure: GHCi crash (amd64) | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I got the following output when trying to load my Haskell project into GHCi using stack: {{{ GHCi, version 8.2.2: http://www.haskell.org/ghc/ :? for help ghc: panic! (the 'impossible' happened) (GHC version 8.2.2 for x86_64-unknown-linux): Loading temp shared object failed: /tmp/ghc3372_0/libghc_13.so: undefined symbol: numStates_g Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} No other informative output was displayed. Output says report the defect, so you get a "bug report." -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14713> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15211: exprFreeVars does not include type variables
by GHC 05 Jun '18

05 Jun '18

#15211: exprFreeVars does not include type variables -------------------------------------+------------------------------------- Reporter: goldfire | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 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: -------------------------------------+------------------------------------- The `exprFreeVars` function returns the free variables of an expression. However, this function doesn't include the type variables free in the free term variables. This might be OK for some uses, but it seems ''not'' OK if we use the result of `exprFreeVars` in an `InScopeSet`, which is done in many places. I don't have a program that exhibits misbehavior, but I feel fairly sure that we have a problem here. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15211> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12075: Fails to build on powerpcspe because of inline assembly
by GHC 05 Jun '18

05 Jun '18

#12075: Fails to build on powerpcspe because of inline assembly --------------------------------+---------------------------------------- Reporter: glaubitz | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Linux Architecture: powerpc | Type of failure: Building GHC failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------+---------------------------------------- Hello! I'm currently bootstrapping GHC on powerpcspe (e500v2) which is a PowerPC architecture without an FPU but with signal processing extensions (hence SPE). When building GHC on this architecture, it detects the host architecture as powerpc-linux-gnuspe or short "powerpc" which works most of the time. However, GHC contains some inline assembly in rts/StgCRunAsm.s which uses FPU instructions not available on e500v2 CPUs resulting in assembler error, here with GHC 7.10.3: {{{ "inplace/bin/ghc-stage1" -optc-fno-stack-protector -optc-Wall -optc-Wextra -optc-Wstrict-prototypes -optc-Wmissing-prototypes -optc-Wmissing- declarations -optc-Winline -optc-Waggregate-return -optc-Wpointer-arith -optc-Wmissing-noreturn -optc-Wnested-externs -optc-Wredundant-decls -optc-Iincludes -optc-Iincludes/dist -optc-Iincludes/dist- derivedconstants/header -optc-Iincludes/dist-ghcconstants/header -optc- Irts -optc-Irts/dist/build -optc-DCOMPILING_RTS -optc- DUSE_LIBFFI_FOR_ADJUSTORS -optc-fno-strict-aliasing -optc-fno-common -optc-Irts/dist/build/autogen -optc-O2 -optc-fomit-frame-pointer -optc-g -optc-DRtsWay=\"rts_v\" -optc-w -static -H32m -O -lffi -optl-pthread -lffi -optl-pthread -Iincludes -Iincludes/dist -Iincludes/dist- derivedconstants/header -Iincludes/dist-ghcconstants/header -Irts -Irts/dist/build -DCOMPILING_RTS -this-package-key rts -dcmm-lint -i -irts -irts/dist/build -irts/dist/build/autogen -Irts/dist/build -Irts/dist/build/autogen -O2 -c rts/StgCRun.c -o rts/dist/build/StgCRun.o /bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8) /bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8) /tmp/ghcf20d_0/ghc_1.s: Assembler messages: /tmp/ghcf20d_0/ghc_1.s:24:0: Error: unrecognized opcode: `stfd' (...) /tmp/ghcf20d_0/ghc_1.s:67:0: Error: unrecognized opcode: `lfd' /tmp/ghcf20d_0/ghc_1.s:68:0: Error: unrecognized opcode: `lfd' /tmp/ghcf20d_0/ghc_1.s:69:0: Error: unrecognized opcode: `lfd' rts/ghc.mk:236: recipe for target 'rts/dist/build/StgCRun.o' failed make[3]: *** [rts/dist/build/StgCRun.o] Error 1 Makefile:71: recipe for target 'all' failed make[2]: *** [all] Error 2 make[2]: Leaving directory '/usr/src/ghc-7.10.3' dh_auto_build: make -j1 returned exit code 2 debian/rules:109: recipe for target 'override_dh_auto_build' failed make[1]: *** [override_dh_auto_build] Error 2 make[1]: Leaving directory '/usr/src/ghc-7.10.3' debian/rules:47: recipe for target 'binary-arch' failed make: *** [binary-arch] Error 2 (sid2-powerpcspe-sbuild)root@atlantis:/usr/src/ghc-7.10.3# }}} This can be verified by commenting out the assembly which will make the above compile command execute without any problems. Trying to continue compiling GHC will still fail with: {{{ "inplace/bin/ghc-stage1" -static -H32m -O -lffi -optl-pthread -lffi -optl-pthread -Iincludes -Iincludes/dist -Iincludes/dist- derivedconstants/header -Iincludes/dist-ghcconstants/header -Irts -Irts/dist/build -DCOMPILING_RTS -this-package-key rts -dcmm-lint -i -irts -irts/dist/build -irts/dist/build/autogen -Irts/dist/build -Irts/dist/build/autogen -O2 -c rts/HeapStackCheck.cmm -o rts/dist/build/HeapStackCheck.o /bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8) /bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8) /tmp/ghcca51_0/ghc_3.s: Assembler messages: /tmp/ghcca51_0/ghc_3.s:525:0: Error: unrecognized opcode: `lfs' /tmp/ghcca51_0/ghc_3.s:538:0: Error: unrecognized opcode: `lfd' /tmp/ghcca51_0/ghc_3.s:592:0: Error: unrecognized opcode: `stfs' /tmp/ghcca51_0/ghc_3.s:604:0: Error: unrecognized opcode: `stfd' rts/ghc.mk:236: recipe for target 'rts/dist/build/HeapStackCheck.o' failed make[3]: *** [rts/dist/build/HeapStackCheck.o] Error 1 Makefile:71: recipe for target 'all' failed make[2]: *** [all] Error 2 make[2]: Leaving directory '/usr/src/ghc-7.10.3' dh_auto_build: make -j1 returned exit code 2 debian/rules:109: recipe for target 'override_dh_auto_build' failed make[1]: *** [override_dh_auto_build] Error 2 make[1]: Leaving directory '/usr/src/ghc-7.10.3' debian/rules:47: recipe for target 'binary-arch' failed make: *** [binary-arch] Error 2 (sid2-powerpcspe-sbuild)root@atlantis:/usr/src/ghc-7.10.3# }}} So, there is obviously more assembly code that needs to be disabled on powerpcspe. For that, I suggest testing whether the compiler sets __NO_FPRS__which is only set on powerpc hosts without FP registers: {{{ root@atlantis:~# echo | gcc -E -dM -|grep -i FP #define __NO_FPRS__ 1 root@atlantis:~# dpkg --print-architecture powerpcspe root@atlantis:~# uname -m ppc root@atlantis:~# }}} For reference, on a real powerpc host, the output is as follows: {{{ (sid_powerpc-dchroot)glaubitz@partch:~$ echo | gcc -E -dM -|grep -i FP #define __FP_FAST_FMAF 1 #define __FP_FAST_FMA 1 (sid_powerpc-dchroot)glaubitz@partch:~$ dpkg --print-architecture powerpc (sid_powerpc-dchroot)glaubitz@partch:~$ uname -m ppc (sid_powerpc-dchroot)glaubitz@partch:~$ }}} If you need any more input, please let me know. Adrian -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12075> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2256: Incompleteness of type inference: must quantify over implication constraints
by GHC 05 Jun '18

05 Jun '18

#2256: Incompleteness of type inference: must quantify over implication constraints -------------------------------------+------------------------------------- Reporter: simonpj | Owner: simonpj Type: bug | Status: closed Priority: lowest | Milestone: Component: Compiler (Type | Version: 6.8.2 checker) | Keywords: Resolution: invalid | QuantifiedConstraints Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by simonpj): * status: new => closed * resolution: => invalid Comment: Right. I don't think we plan (ever) to infer a quantified constraint. Let's just close this. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2256#comment:31> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14735: GHC Panic with QuantifiedConstraints
by GHC 05 Jun '18

05 Jun '18

#14735: GHC Panic with QuantifiedConstraints -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 Keywords: | Operating System: Unknown/Multiple QuantifiedContexts | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- From branch [https://ghc.haskell.org/trac/ghc/ticket/2893#comment:28 wip/T2893] {{{#!hs {-# Language QuantifiedConstraints #-} {-# Language StandaloneDeriving #-} {-# Language DataKinds #-} {-# Language TypeOperators #-} {-# Language GADTs #-} {-# Language KindSignatures #-} {-# Language FlexibleInstances #-} {-# Language UndecidableInstances #-} {-# Language MultiParamTypeClasses #-} {-# Language RankNTypes #-} {-# Language ConstraintKinds #-} import Data.Kind data D c where D :: c => D c newtype a :- b = S (a => D b) class C1 a b class C2 a b instance C1 a b => C2 a b class (forall xx. f xx) => Limit f instance (forall xx. f xx) => Limit f -- impl :: Limit (C1 a) :- Limit (C2 a) -- impl = S D infixr 5 :< data Sig a = N a | a :< Sig a data AST :: (Sig Type -> Type) -> (Sig Type -> Type) where Sym :: dom a -> AST dom a (:$) :: AST dom (xx :< a) -> AST dom (N xx) -> AST dom a deriving instance (forall xx. Show (dom xx)) => Show (AST dom a) data Arith a where Plus :: Arith (Int :< Int :< N Int) deriving instance Show (Arith a) }}} loading this program and evaluating `Sym Plus` works fine: {{{ $ ghc-stage2 --interactive hs/175-bug.hs GHCi, version 8.5.20180128: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( hs/175-bug.hs, interpreted ) Ok, one module loaded. *Main> Sym Plus Sym Plus *Main> }}} but we uncomment `impl` we get a panic! {{{ GHCi, version 8.5.20180128: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( hs/175-bug.hs, interpreted ) Ok, one module loaded. *Main> Sym Plus ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.5.20180128 for x86_64-unknown-linux): nameModule system df_a2VB Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1150:37 in ghc:Outputable pprPanic, called at compiler/basicTypes/Name.hs:241:3 in ghc:Name Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug *Main> }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14735> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14961: QuantifiedConstraints: class name introduced via an equality constraint does not reduce
by GHC 05 Jun '18

05 Jun '18

#14961: QuantifiedConstraints: class name introduced via an equality constraint does not reduce -------------------------------------+------------------------------------- Reporter: mrkgnao | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Keywords: | Operating System: Unknown/Multiple QuantifiedConstraints wipT2893 | Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: #14860 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The following doesn't typecheck with the `wip/T2893` branch: {{{#!hs {-# LANGUAGE QuantifiedConstraints #-} {-# LANGUAGE TypeOperators #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE UndecidableInstances #-} {-# LANGUAGE ConstraintKinds #-} {-# LANGUAGE TypeFamilies #-} module Subst where class (forall x. c x => d x) => c ~=> d instance (forall x. c x => d x) => c ~=> d foo :: forall c a. c ~=> Monoid => (c a => a) -- ok foo = mempty bar :: forall c a m. (m ~ Monoid, c ~=> m) => (c a => a) -- ok bar = mempty baz :: forall c a. (forall m. m ~ Monoid => c ~=> m) => (c a => a) -- fails baz = mempty }}} {{{ Prelude> :reload [1 of 1] Compiling Subst ( src/Subst.hs, interpreted ) src/Subst.hs:21:7: error: • Could not deduce (Monoid a) arising from a use of ‘mempty’ from the context: (forall (m :: * -> Constraint). (m ~ Monoid) => c ~=> m, c a) bound by the type signature for: baz :: forall (c :: * -> Constraint) a. (forall (m :: * -> Constraint). (m ~ Monoid) => c ~=> m, c a) => a at src/Subst.hs:20:1-66 Possible fix: add (Monoid a) to the context of the type signature for: baz :: forall (c :: * -> Constraint) a. (forall (m :: * -> Constraint). (m ~ Monoid) => c ~=> m, c a) => a • In the expression: mempty In an equation for ‘baz’: baz = mempty | 21 | baz = mempty | ^^^^^^ Failed, no modules loaded. }}} Shouldn't the equality constraint be "substituted in"? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14961> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14863: QuantifiedConstraints: Can't deduce `c' from `(a, b)' and `a |- b |- c'
by GHC 05 Jun '18

05 Jun '18

#14863: QuantifiedConstraints: Can't deduce `c' from `(a, b)' and `a |- b |- c' -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Keywords: | Operating System: Unknown/Multiple QuantifiedConstraints wipT2893 | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- #14833 fixes #14835: we can witness `curryC :: ((a, b) |- c) :- (a |- b |- c)`. Now for the entirely predictable, how about **un**`curryC` {{{#!hs {-# Language QuantifiedConstraints, RankNTypes, PolyKinds, ConstraintKinds, UndecidableInstances, GADTs, LiberalTypeSynonyms, TypeOperators, MultiParamTypeClasses, FlexibleInstances #-} data Dict c where Dict :: c => Dict c infixr |- class (a => b) => (a |- b) instance (a => b) => (a |- b) type a :- b = Dict (a |- b) uncurryC :: forall a b c. (a |- b |- c) :- ((a, b) |- c) uncurryC = Dict }}} {{{ $ ghci -ignore-dot-ghci Z.hs GHCi, version 8.5.20180128: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( Z.hs, interpreted ) Z.hs:13:12: error: • Could not deduce: c arising from a use of ‘Dict’ from the context: a |- (b |- c) bound by a quantified context at Z.hs:1:1 or from: (a, b) bound by a quantified context at Z.hs:1:1 • In the expression: Dict In an equation for ‘uncurryC’: uncurryC = Dict • Relevant bindings include uncurryC :: (a |- (b |- c)) :- ((a, b) |- c) (bound at Z.hs:13:1) | 13 | uncurryC = Dict | ^^^^ Failed, no modules loaded. Prelude> }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14863> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2256: Incompleteness of type inference: must quantify over implication constraints
by GHC 05 Jun '18

05 Jun '18

#2256: Incompleteness of type inference: must quantify over implication constraints -------------------------------------+------------------------------------- Reporter: simonpj | Owner: simonpj Type: bug | Status: new Priority: lowest | Milestone: Component: Compiler (Type | Version: 6.8.2 checker) | Keywords: Resolution: | QuantifiedConstraints Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): Simon, it's unclear what we should do with this ticket now that `QuantifiedConstraints` are in GHC. Was the intention here to actually change GHC to infer quantified constraints in certain places? My hunch is "no", especially in light of comment:16. If so, can we simply close this ticket? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2256#comment:30> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2893: Implement "Quantified constraints" proposal
by GHC 05 Jun '18

05 Jun '18

#2893: Implement "Quantified constraints" proposal -------------------------------------+------------------------------------- Reporter: porges | Owner: (none) Type: feature request | Status: closed Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 6.10.1 Resolution: fixed | Keywords: | QuantifiedConstraints, GHCProposal Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: quantified- | constraints/T2893{,a,c} Blocked By: | Blocking: Related Tickets: #5927 | Differential Rev(s): Phab:D4724 Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * status: new => closed * testcase: => quantified-constraints/T2893{,a,c} * resolution: => fixed * milestone: ⊥ => 8.6.1 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2893#comment:41> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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