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[GHC] #14457: Data family with non-Type return kind, can't figure out type despite annotating
by GHC 12 Nov '17

12 Nov '17

#14457: Data family with non-Type return kind, can't figure out type despite annotating -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | 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: #12369 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# Language KindSignatures, DataKinds, TypeFamilyDependencies, GADTs, TypeInType #-} import Data.Kind type family ToNat (n::Type) = (res :: Type) | res -> n where ToNat Type = Bool ToNat (Type -> Type) = Maybe Bool data family FN :: ToNat ty -> ty data instance FN :: Bool -> Type where F :: FN False T :: FN True data instance FN :: Maybe Bool -> (Type -> Type) where A :: FN (Nothing :: Maybe Bool) a B :: a -> FN (Just False) a C :: a -> a -> FN (Just True) a }}} works on GHC 8.3.20170920, but removing the annotation from `(Nothing :: Maybe Bool)` yields {{{ GHCi, version 8.3.20170920: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( /tmp/Z.hs, interpreted ) /tmp/Z.hs:19:22: error: • Expected kind ‘ToNat (k0 -> *)’, but ‘Nothing’ has kind ‘Maybe a0’ • In the first argument of ‘FN’, namely ‘Nothing’ In the type ‘FN Nothing a’ In the definition of data constructor ‘A’ | 19 | A :: FN Nothing a | ^^^^^^^ Failed, 0 modules loaded. Prelude> }}} even though `FN` is annotated with the expected kind of `Nothing`: {{{#!hs data FN :: Maybe Bool -> ... where }}} can also be fixed by annotating `A :: FN Nothing (a::Type)`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14457> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14311: PowerPC: Symbol already defined
by GHC 11 Nov '17

11 Nov '17

#14311: PowerPC: Symbol already defined --------------------------------+---------------------------------------- Reporter: trommler | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.3 Keywords: | Operating System: Unknown/Multiple Architecture: powerpc | Type of failure: Building GHC failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------+---------------------------------------- Building HEAD I get the following error from the stage 1 compiler: {{{ /tmp/ghc9106_0/ghc_4.s:796:0: error: Error: symbol `.Lc2l' is already defined | 796 | .Lc2l: | ^ `gcc' failed in phase `Assembler'. (Exit code: 1) rts/ghc.mk:269: recipe for target 'rts/dist/build/Exception.o' failed }}} The relevant assembly code is: {{{ .section ".opd","aw" .align 3 .LcV: .quad ..LcV,.TOC.@tocbase,0 .previous .type .LcV, @function ..LcV: .LcV: ld 31, 8(22) }}} Note: The label has changed during recompile. This affects powerpc64 (ELF 1.9) and powerpc64le (ELF 2.0) on Linux and I suspect also AIX. This could be a fallout from: changeset:8b007abbeb3045900a11529d907a835080129176 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14311> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13990: Core Lint error on empty case
by GHC 11 Nov '17

11 Nov '17

#13990: Core Lint error on empty case -------------------------------------+------------------------------------- Reporter: mbieleck | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc3 Keywords: core-lint | Operating System: Unknown/Multiple case | Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This module: {{{#!hs {-# LANGUAGE EmptyCase #-} module Bug where data Void absurd :: Void -> a absurd v = case v of {} data Foo = Foo !Void absurdFoo :: Foo -> a absurdFoo (Foo x) = absurd x }}} Compiled using `ghc-8.2.0.20170704 -O -dcore-lint Bug.hs` Gives the following error: {{{ [1 of 1] Compiling Bug ( Bug.hs, Bug.o ) *** Core Lint errors : in result of Simplifier *** <no location info>: warning: In a case alternative: (Foo x_ap6 :: Void) No alternatives for a case scrutinee in head-normal form: x_ap6 *** Offending Program *** absurd :: forall a. Void -> a [LclIdX, Arity=1, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=True)}] absurd = \ (@ a_apU) (v_ap5 :: Void) -> case v_ap5 of { } absurdFoo :: forall a. Foo -> a [LclIdX, Arity=1, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=True)}] absurdFoo = \ (@ a_apY) (ds_dUn :: Foo) -> case ds_dUn of { Foo x_ap6 -> case x_ap6 of { } } -- irrelevant stuff omitted }}} When I manually inline `absurd` or remove the strictness annotation on `Foo`, the error goes away. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13990> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14425: approxRational is wrong when (rat - eps) overflows in negative direction
by GHC 11 Nov '17

11 Nov '17

#14425: approxRational is wrong when (rat - eps) overflows in negative direction -------------------------------------+------------------------------------- Reporter: danielk | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: | Version: 8.2.1 libraries/base | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect result Unknown/Multiple | at runtime Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This program is wrong. The second output should be 0 % 1. {{{ import Data.Ratio main = do print (approxRational (0 % 1 :: Ratio Int) (1 % 10)) -- 0%1, correct print (approxRational (0 % 1 :: Ratio Word) (1 % 10)) -- 1%1, incorrect }}} The problem is that (rat-eps) overflows in the negative direction (see [http://hackage.haskell.org/package/base-4.10.0.0/docs/src/Data.Ratio.html#a… source]). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14425> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14349: Semigroup/Monoid instances for System.Exit.ExitCode
by GHC 11 Nov '17

11 Nov '17

#14349: Semigroup/Monoid instances for System.Exit.ExitCode -------------------------------------+------------------------------------- Reporter: neil.mayhew | Owner: (none) Type: feature | Status: new request | Priority: low | Milestone: Component: | Version: 8.2.1 libraries/base | 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: -------------------------------------+------------------------------------- Please add instances for ExitCode along the following lines: {{{#!hs instance Monoid ExitCode where mempty = ExitSuccess mappend ExitSuccess b = b mappend a _ = a }}} This allows the summary result of multiple child processes to be computed naturally. For example: {{{#!hs mconcat <$> mapM system commands }}} The result is `ExitSuccess` if they all succeeded, and the leftmost failure otherwise -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14349> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9420: Impredicative type instantiation without -XImpredicativeTypes
by GHC 11 Nov '17

11 Nov '17

#9420: Impredicative type instantiation without -XImpredicativeTypes -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Consider this module: {{{ {-# LANGUAGE RankNTypes #-} module Bug where rank2 :: ((forall a. a -> a) -> b) -> () rank2 _ = () foo :: () -> () foo x = x quux :: (forall a. a -> a) -> Int quux _ = 5 bar = foo . rank2 $ quux }}} The `(.)` in the definition of `bar` requires an impredicative instantiation -- that is, one of its type variables is instantiated to a forall-type. Yet, the module compiles without `-XImpredicativeTypes`. To confirm this behavior, the following is an excerpt from `-ddump-simpl`: {{{ Bug.bar = break<7>() (break<6>() GHC.Base.. @ () @ () @ ((forall a_a1Tj. a_a1Tj -> a_a1Tj) -> GHC.Types.Int) Bug.foo (Bug.rank2 @ GHC.Types.Int)) Bug.quux }}} Note the third type argument to `(.)`. Fixing this would be a breaking change that could affect users. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9420> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14453: CircleCI builds on Linux spuriously fail
by GHC 11 Nov '17

11 Nov '17

#14453: CircleCI builds on Linux spuriously fail -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: bug | Status: new Priority: high | Milestone: 8.4.1 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: -------------------------------------+------------------------------------- See, for instance, [[https://circleci.com/api/v1.1/project/github/ghc/ghc/256/output/107/0?file=… #256]]. This build seemed to be chugging along quite nicely when at minute 30 it failed with, {{{ "inplace/bin/ghc-stage1" -hisuf p_hi -osuf p_o -hcsuf p_hc -static -prof -eventlog -H32m -O -Wall -Iincludes -Iincludes/dist -Iincludes/dist- derivedconstants/header -Iincludes/dist-ghcconstants/header -this-unit- id ghc-8.3 -hide-all-packages -i -icompiler/backpack -icompiler/basicTypes -icompiler/cmm -icompiler/codeGen -icompiler/coreSyn -icompiler/deSugar -icompiler/ghci -icompiler/hsSyn -icompiler/iface -icompiler/llvmGen -icompiler/main -icompiler/nativeGen -icompiler/parser -icompiler/prelude -icompiler/profiling -icompiler/rename -icompiler/simplCore -icompiler/simplStg -icompiler/specialise -icompiler/stgSyn -icompiler/stranal -icompiler/typecheck -icompiler/types -icompiler/utils -icompiler/vectorise -icompiler/stage2/build -Icompiler/stage2/build -icompiler/stage2/build/./autogen -Icompiler/stage2/build/./autogen -Icompiler/. -Icompiler/parser -Icompiler/utils -Icompiler/../rts/dist/build -Icompiler/stage2 -optP-DGHCI -optP-include -optPcompiler/stage2/build/./autogen/cabal_macros.h -package-id base-4.11.0.0 -package-id deepseq-1.4.3.0 -package-id directory-1.3.1.5 -package-id process-1.6.1.0 -package-id bytestring-0.10.8.2 -package-id binary-0.8.5.1 -package-id time-1.8.0.2 -package-id containers-0.5.10.2 -package-id array-0.5.2.0 -package-id filepath-1.4.1.2 -package-id template-haskell-2.13.0.0 -package-id hpc-0.6.0.3 -package-id transformers-0.5.4.0 -package-id ghc-boot-8.3 -package-id ghc-boot-th-8.3 -package-id ghci-8.3 -package-id unix-2.7.2.2 -package-id terminfo-0.4.1.0 -Wall -Wno-name-shadowing -Wnoncanonical-monad-instances -Wnoncanonical- monadfail-instances -Wnoncanonical-monoid-instances -this-unit-id ghc -XHaskell2010 -XNoImplicitPrelude -optc-DTHREADED_RTS -DGHCI_TABLES_NEXT_TO_CODE -DSTAGE=2 -Rghc-timing -O2 -Wcpp-undef -no- user-package-db -rtsopts -Wnoncanonical-monad-instances -odir compiler/stage2/build -hidir compiler/stage2/build -stubdir compiler/stage2/build -c compiler/hsSyn/HsDecls.hs -o compiler/stage2/build/HsDecls.p_o -dyno compiler/stage2/build/HsDecls.dyn_o ... compiler/ghc.mk:447: recipe for target 'compiler/stage2/build/HsDecls.p_o' failed make[1]: *** [compiler/stage2/build/HsDecls.p_o] Killed }}} Why was it killed? No one knows. I suspect it ran out of memory since it appears that there was at least seven other GHC processes running concurrently on a machine with only 4 gigabytes of memory. However, seeing as there's no way to tell whether the OOM killer was invoked it's hard to know for certain. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14453> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #450: "class A where a :: A -> Int" panics GHC 6.4
by GHC 11 Nov '17

11 Nov '17

#450: "class A where a :: A -> Int" panics GHC 6.4 --------------------------------+-------------------- Reporter: carlossch | Owner: nobody Type: bug | Status: closed Priority: normal | Milestone: Component: None | Version: None Resolution: Duplicate | Keywords: Type of failure: None/Unknown | --------------------------------+-------------------- Changes (by Ben Gamari <ben@…>): * failure: => None/Unknown Comment: In [changeset:"5229c43ccf77bcbffeced01dccb27398d017fa34/ghc" 5229c43c/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="5229c43ccf77bcbffeced01dccb27398d017fa34" Squashed 'hadrian/' changes from 438dc576e7..5ebb69ae1e 5ebb69ae1e Drop GccLtXX flags, require GCC > 4.7 and up (#450) git-subtree-dir: hadrian git-subtree-split: 5ebb69ae1eb063f25c59383bffb3b5449015c6f9 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/450#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14432: Outdated comment in GHC.Real
by GHC 11 Nov '17

11 Nov '17

#14432: Outdated comment in GHC.Real -------------------------------------+------------------------------------- Reporter: Bodigrim | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Documentation | Version: 8.2.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Documentation Unknown/Multiple | bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- `GHC.Real` (lines 518-534) says: {{{ {- Rules for powers with known small exponent ... It might be desirable to have corresponding rules also for exponents of other types, in particular Word, but we can't have those rules here (importing GHC.Word or GHC.Int would create a cyclic module dependency), and it's doubtful they would fire, since the exponents of other types tend to get floated out before the rule has a chance to fire. }}} The remark about cyclic module dependency seems to be outdated: nowadays `GHC.Real` certainly has `Word` in scope. My proposal is to exclude this remark and change the paragraph to {{{ It might be desirable to have corresponding rules also for exponents of other types (e. g., Word), but it's doubtful they would fire, since the exponents of other types tend to get floated out before the rule has a chance to fire. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14432> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2431: Allow empty case analysis
by GHC 11 Nov '17

11 Nov '17

#2431: Allow empty case analysis -----------------------------+--------------------------------------------- Reporter: | Owner: (none) RalfHinze | Type: feature | Status: closed request | Priority: low | Milestone: ⊥ Component: Compiler | Version: 6.8.3 Resolution: fixed | Keywords: empty case analysis Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Type of failure: | Test Case: deSugar/should_compile/T2431 None/Unknown | Blocked By: | Blocking: Related Tickets: | -----------------------------+--------------------------------------------- Changes (by Smartmiltoys): * Attachment "bilets-2018-1.jpg" added. annabelle dollhouses find by [http://smartmiltoys.com/kidkraft-dollhouse /kidkraft-annabelle-dollhouse-65079/ click] this link -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2431> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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