December 2018 - ghc-tickets

[GHC] #13971: Misleading "Kind mis-match on LHS of default declaration" error
by GHC 19 Feb '19

19 Feb '19

#13971: Misleading "Kind mis-match on LHS of default declaration" error -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 (Type checker) | Keywords: TypeFamilies | Operating System: Unknown/Multiple Architecture: | Type of failure: Poor/confusing Unknown/Multiple | error message Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This program fails to typecheck, unsurprisingly: {{{#!hs {-# LANGUAGE PolyKinds #-} {-# LANGUAGE TypeFamilies #-} module Bug where class C a where type T a :: k type T a = Int }}} But the error message it gives threw me for a loop initially: {{{ $ /opt/ghc/8.2.1/bin/ghci Bug.hs GHCi, version 8.2.0.20170704: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Bug.hs, interpreted ) Bug.hs:7:3: error: • Kind mis-match on LHS of default declaration for ‘T’ • In the default type instance declaration for ‘T’ In the class declaration for ‘C’ | 7 | type T a = Int | ^^^^^^^^^^^^^^ Failed, 0 modules loaded. }}} The LHS of the default declaration is perfectly fine - the real source of the error is the RHS! -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13971> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13706: ghci messages like "Ok, modules loaded: ..." are impractical for large sets of modules
by GHC 19 Feb '19

19 Feb '19

#13706: ghci messages like "Ok, modules loaded: ..." are impractical for large sets of modules -------------------------------------+------------------------------------- Reporter: j.waldmann | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: GHCi | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Poor/confusing Unknown/Multiple | error message Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Ghci (in the default config) wants to show me all the modules that are currently loaded. If I have a great many of these (think: hundreds) then this is impractical, because I have to scroll back to see what actually interests me (output of last command). I can change the prompt (`:set prompt "> "`), but I don't see how to switch off the display of all module names in `:r` command. I have to scroll back (several screenfulls) to even find out whether the reload was successful, since the status (OK/Failed) is at the very beginning - and the reason for the Failure is before that. Cf. https://mail.haskell.org/pipermail/haskell-cafe/2017-May/126983.html (but there was no reaction) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13706> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14040: Typed holes regression in GHC 8.0.2: No skolem info: z_a1sY[sk:2]
by GHC 18 Feb '19

18 Feb '19

#14040: Typed holes regression in GHC 8.0.2: No skolem info: z_a1sY[sk:2] -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 (Type checker) | Keywords: TypeInType, | Operating System: Unknown/Multiple TypeFamilies, | PartialTypeSignatures | Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: #13877 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- (Originally spun off from #13877.) The following program gives a somewhat decent error message in GHC 8.0.1: {{{#!hs {-# LANGUAGE GADTs #-} {-# LANGUAGE RankNTypes #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE TypeApplications #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE TypeInType #-} module Bug where import Data.Kind data family Sing (a :: k) data WeirdList :: Type -> Type where WeirdNil :: WeirdList a WeirdCons :: a -> WeirdList (WeirdList a) -> WeirdList a data instance Sing (z :: WeirdList a) where SWeirdNil :: Sing WeirdNil SWeirdCons :: Sing w -> Sing wws -> Sing (WeirdCons w wws) elimWeirdList :: forall (a :: Type) (wl :: WeirdList a) (p :: forall (x :: Type). x -> WeirdList x -> Type). Sing wl -> (forall (y :: Type). p _ WeirdNil) -> (forall (z :: Type) (x :: z) (xs :: WeirdList (WeirdList z)). Sing x -> Sing xs -> p _ xs -> p _ (WeirdCons x xs)) -> p _ wl elimWeirdList SWeirdNil pWeirdNil _ = pWeirdNil elimWeirdList (SWeirdCons (x :: Sing (x :: z)) (xs :: Sing (xs :: WeirdList (WeirdList z)))) pWeirdNil pWeirdCons = pWeirdCons @z @x @xs x xs (elimWeirdList @(WeirdList z) @xs @p xs pWeirdNil pWeirdCons) }}} {{{ $ /opt/ghc/8.0.1/bin/ghci Foo.hs GHCi, version 8.0.1: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Foo.hs, interpreted ) Foo.hs:34:8: error: • Cannot apply expression of type ‘Sing wl -> (forall y. p x0 t3 'WeirdNil) -> (forall z (x :: z) (xs :: WeirdList (WeirdList z)). Sing x -> Sing xs -> p (WeirdList z) t2 xs -> p z t1 ('WeirdCons x xs)) -> p a t0 wl’ to a visible type argument ‘WeirdList z’ • In the sixth argument of ‘pWeirdCons’, namely ‘(elimWeirdList @(WeirdList z) @xs @p xs pWeirdNil pWeirdCons)’ In the expression: pWeirdCons @z @x @xs x xs (elimWeirdList @(WeirdList z) @xs @p xs pWeirdNil pWeirdCons) In an equation for ‘elimWeirdList’: elimWeirdList (SWeirdCons (x :: Sing (x :: z)) (xs :: Sing (xs :: WeirdList (WeirdList z)))) pWeirdNil pWeirdCons = pWeirdCons @z @x @xs x xs (elimWeirdList @(WeirdList z) @xs @p xs pWeirdNil pWeirdCons) }}} But in GHC 8.0.2, 8.2.1, and HEAD, it panics to varying degrees: {{{ $ /opt/ghc/8.0.2/bin/ghci Foo.hs GHCi, version 8.0.2: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Foo.hs, interpreted ) Foo.hs:24:41: error: • Found type wildcard ‘_’ standing for ‘t0’ Where: ‘t0’ is an ambiguous type variable ‘x0’ is an ambiguous type variable To use the inferred type, enable PartialTypeSignatures • In the type signature: elimWeirdList :: forall (a :: Type) (wl :: WeirdList a) (p :: forall (x :: Type). x -> WeirdList x -> Type). Sing wl -> (forall (y :: Type). p _ WeirdNil) -> (forall (z :: Type) (x :: z) (xs :: WeirdList (WeirdList z)). Sing x -> Sing xs -> p _ xs -> p _ (WeirdCons x xs)) -> p _ wl • Relevant bindings include elimWeirdList :: Sing wl -> (forall y. p x0 t0 'WeirdNil) -> (forall z (x :: z) (xs :: WeirdList (WeirdList z)). Sing x -> Sing xs -> p (WeirdList z) t1 xs -> p z t2 ('WeirdCons x xs)) -> p a t3 wl (bound at Foo.hs:29:1) Foo.hs:26:44: error:ghc: panic! (the 'impossible' happened) (GHC version 8.0.2 for x86_64-unknown-linux): No skolem info: z_a13X[sk] }}} {{{ $ /opt/ghc/8.2.1/bin/ghci Foo.hs GHCi, version 8.2.1: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Foo.hs, interpreted ) Foo.hs:21:18: error: • The kind of variable ‘wl1’, namely ‘WeirdList a1’, depends on variable ‘a1’ from an inner scope Perhaps bind ‘wl1’ sometime after binding ‘a1’ • In the type signature: elimWeirdList :: forall (a :: Type) (wl :: WeirdList a) (p :: forall (x :: Type). x -> WeirdList x -> Type). Sing wl -> (forall (y :: Type). p _ WeirdNil) -> (forall (z :: Type) (x :: z) (xs :: WeirdList (WeirdList z)). Sing x -> Sing xs -> p _ xs -> p _ (WeirdCons x xs)) -> p _ wl | 21 | elimWeirdList :: forall (a :: Type) (wl :: WeirdList a) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^... Foo.hs:24:41: error: • Found type wildcard ‘_’ standing for ‘w0’ Where: ‘w0’ is an ambiguous type variable ‘x0’ is an ambiguous type variable To use the inferred type, enable PartialTypeSignatures • In the type signature: elimWeirdList :: forall (a :: Type) (wl :: WeirdList a) (p :: forall (x :: Type). x -> WeirdList x -> Type). Sing wl -> (forall (y :: Type). p _ WeirdNil) -> (forall (z :: Type) (x :: z) (xs :: WeirdList (WeirdList z)). Sing x -> Sing xs -> p _ xs -> p _ (WeirdCons x xs)) -> p _ wl | 24 | -> (forall (y :: Type). p _ WeirdNil) | ^ Foo.hs:26:44: error:ghc: panic! (the 'impossible' happened) (GHC version 8.2.1 for x86_64-unknown-linux): No skolem info: z_a1sY[sk:2] Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1133:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1137:37 in ghc:Outputable pprPanic, called at compiler/typecheck/TcErrors.hs:2653:5 in ghc:TcErrors }}} (The error messages from HEAD, at commit 791947db6db32ef7d4772a821a0823e558e3c05b, are the same as in GHC 8.2.1.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14040> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12612: Allow kinds of associated types to depend on earlier associated types
by GHC 18 Feb '19

18 Feb '19

#12612: Allow kinds of associated types to depend on earlier associated types -------------------------------------+------------------------------------- Reporter: davemenendez | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 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: -------------------------------------+------------------------------------- GHC rejects the following code: {{{#!hs class C t where type K t :: Type type T t :: K t -> Type m :: t -> T t a }}} with this error message {{{ • Type constructor ‘K’ cannot be used here (it is defined and used in the same recursive group) • In the kind ‘K t -> Type’ }}} See [https://mail.haskell.org/pipermail/glasgow-haskell- users/2016-September/026402.html e-mail discussion]. This is connected to #12088, at least as far as defining instances of C. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12612> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12218: Implement -fexternal-interpreter via static linking
by GHC 18 Feb '19

18 Feb '19

#12218: Implement -fexternal-interpreter via static linking -------------------------------------+------------------------------------- Reporter: simonmar | Owner: Type: task | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 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: -------------------------------------+------------------------------------- An interesting idea from @hvr. When using `-fexternal-interpreter`, we can statically link the required packages and object files into a new iconv binary, and use that as our external interpreter. This would mean we could support TH and even limited GHCi without needing a dynamic linker of any kind, which is extremely cool. Apparently this would be useful for AIX where doing dynamic linking is hard. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12218> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14860: QuantifiedConstraints: Can't quantify constraint involving type family
by GHC 17 Feb '19

17 Feb '19

#14860: QuantifiedConstraints: Can't quantify constraint involving type family -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 (Type checker) | Keywords: | Operating System: Unknown/Multiple QuantifiedConstraints wipT2893 | Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This program fails to typecheck using the `wip/T2893` branch, to my surprise: {{{#!hs {-# LANGUAGE AllowAmbiguousTypes #-} {-# LANGUAGE GADTs #-} {-# LANGUAGE QuantifiedConstraints #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE UndecidableInstances #-} module Bug where import Data.Proxy type family Apply (f :: * -> *) a type instance Apply Proxy a = Proxy a data ExTyFam f where MkExTyFam :: Apply f a -> ExTyFam f instance (forall a. Show (Apply f a)) => Show (ExTyFam f) where show (MkExTyFam x) = show x showsPrec = undefined -- Not defining these leads to the oddities observed in showList = undefined -- https://ghc.haskell.org/trac/ghc/ticket/5927#comment:32 test :: ExTyFam Proxy -> String test = show }}} This fails with: {{{ $ ghc-cq/inplace/bin/ghc-stage2 --interactive Bug.hs GHCi, version 8.5.20180128: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Bug.hs, interpreted ) Bug.hs:17:24: error: • Could not deduce (Show (Apply f a)) arising from a use of ‘show’ from the context: forall a. Show (Apply f a) bound by the instance declaration at Bug.hs:16:10-57 • In the expression: show x In an equation for ‘show’: show (MkExTyFam x) = show x In the instance declaration for ‘Show (ExTyFam f)’ | 17 | show (MkExTyFam x) = show x | ^^^^^^ }}} I would have expected the `(forall a. Show (Apply f a))` quantified constraint to kick in, but it didn't. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14860> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15579: topNormaliseType is wrong
by GHC 15 Feb '19

15 Feb '19

#15579: topNormaliseType is wrong -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: high | 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: -------------------------------------+------------------------------------- I’m very puzzled about topNormaliseTYpe_maybe. Here it is: {{{ topNormaliseType_maybe env ty = topNormaliseTypeX stepper mkTransCo ty where stepper = unwrapNewTypeStepper `composeSteppers` tyFamStepper tyFamStepper rec_nts tc tys -- Try to step a type/data family = let (args_co, ntys) = normaliseTcArgs env Representational tc tys in -- NB: It's OK to use normaliseTcArgs here instead of -- normalise_tc_args (which takes the LiftingContext described -- in Note [Normalising types]) because the reduceTyFamApp below -- works only at top level. We'll never recur in this function -- after reducing the kind of a bound tyvar. case reduceTyFamApp_maybe env Representational tc ntys of Just (co, rhs) -> NS_Step rec_nts rhs (args_co `mkTransCo` co) _ -> NS_Done }}} I have two puzzlements 1. First, it seems utterly wrong to normalise the arguments using Representational. Consider {{{ F (N Int) where newtype N x = [x] }}} We don’t want to reduce `(N Int)` to `[Int]`, and then try reducing `(F [Int])`!! That is totally bogus. Surely we should use (the role-aware) `normalise_tc_args` here? 2. I have literally no clue what `Note [Normalising types]` is all about. Moreover there is no Lifting Context passed to `normalise_tc_args`, so I don’t know what this stuff about `LiftingContext` is about. Is this historical baggage? Richard and I discussed this. (1) is a bug; for (2) the comment is misleading and should be deleted. Richard will do these things -- and will add examples to the mysterious `Note [Normalising types]` -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15579> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11786: Need -fno-print-explicit-runtime-reps to work on IfaceType, else RuntimeRep leaks
by GHC 15 Feb '19

15 Feb '19

#11786: Need -fno-print-explicit-runtime-reps to work on IfaceType, else RuntimeRep leaks -------------------------------------+------------------------------------- Reporter: simonpj | 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: -------------------------------------+------------------------------------- After #11549, we are suppose not to show `RuntimeRep` to users, when `-fno-print-explicit-runtime-reps` is on. But we do: {{{ :info ($) Prelude> :i ($) ($) :: forall (r :: GHC.Types.RuntimeRep) a (b :: TYPE r). (a -> b) -> a -> b -- Defined in ‘GHC.Base’ }}} This happens because the runtime-rep-suppression happens on `Type`, but for `:info` we use `pprInfo` which uses `tyThingToIfaceDecl` and then prints it. And `tyThingToIfaceDecl` doesn't know about the `-fprint- explicit-runtime-reps` flag; and I'd like to keep it that way. We want to change `pprType` to convert to `IfaceType` and then print anyway. I suppose that this means that the pretty-printer for `IfaceType` needs to know about this runtime-rep suppression. That's a bit tiresome, but not impossible, especially since there is no shadowing to worry about. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11786> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10187: Panic: RegAlloc.Liveness.computeLivenss; SCCs aren't in reverse dependent order; bad blockId c8xHd
by GHC 15 Feb '19

15 Feb '19

#10187: Panic: RegAlloc.Liveness.computeLivenss; SCCs aren't in reverse dependent order; bad blockId c8xHd -----------------------------------+--------------------------------------- Reporter: mietek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.4 Keywords: | Operating System: Linux Architecture: x86 | Type of failure: Compile-time crash Test Case: | Blocked By: Blocking: | Related Tickets: #9541, #9031 Differential Revisions: | -----------------------------------+--------------------------------------- I’ve found another instance of the elusive `RegAlloc.Liveness.computeLivenss` bug, by attempting to bootstrap ''cabal-install'' 1.20.0.6 with GHC 7.8.4 on 32-bit CentOS 6, released on 27/05/2013 (available on [https://aws.amazon.com/marketplace/pp/B00A6KZBC6/ Amazon EC2]). Unfortunately, I’m unable to reproduce the bug on a subsequent attempt. Cosmic rays? {{{ Configuring text-1.1.0.1... Building text-1.1.0.1... Preprocessing library text-1.1.0.1... [ 1 of 43] Compiling Data.Text.Internal.Read ( Data/Text/Internal/Read.hs, dist/build/Data/Text/Internal/Read.o ) [ 2 of 43] Compiling Data.Text.Internal.Encoding.Utf32 ( Data/Text/Internal/Encoding/Utf32.hs, dist/build/Data/Text/Internal/Encoding/Utf32.o ) [ 3 of 43] Compiling Data.Text.Internal.Fusion.Size ( Data/Text/Internal/Fusion/Size.hs, dist/build/Data/Text/Internal/Fusion/Size.o ) [ 4 of 43] Compiling Data.Text.Internal.Builder.RealFloat.Functions ( Data/Text/Internal/Builder/RealFloat/Functions.hs, dist/build/Data/Text/Internal/Builder/RealFloat/Functions.o ) [ 5 of 43] Compiling Data.Text.Internal.Builder.Int.Digits ( Data/Text/Internal/Builder/Int/Digits.hs, dist/build/Data/Text/Internal/Builder/Int/Digits.o ) [ 6 of 43] Compiling Data.Text.Internal.Fusion.Types ( Data/Text/Internal/Fusion/Types.hs, dist/build/Data/Text/Internal/Fusion/Types.o ) [ 7 of 43] Compiling Data.Text.Internal.Fusion.CaseMapping ( Data/Text/Internal/Fusion/CaseMapping.hs, dist/build/Data/Text/Internal/Fusion/CaseMapping.o ) [ 8 of 43] Compiling Data.Text.Encoding.Error ( Data/Text/Encoding/Error.hs, dist/build/Data/Text/Encoding/Error.o ) [ 9 of 43] Compiling Data.Text.Internal.Unsafe.Shift ( Data/Text/Internal/Unsafe/Shift.hs, dist/build/Data/Text/Internal/Unsafe/Shift.o ) [10 of 43] Compiling Data.Text.Internal.Encoding.Utf16 ( Data/Text/Internal/Encoding/Utf16.hs, dist/build/Data/Text/Internal/Encoding/Utf16.o ) [11 of 43] Compiling Data.Text.Internal.Functions ( Data/Text/Internal/Functions.hs, dist/build/Data/Text/Internal/Functions.o ) [12 of 43] Compiling Data.Text.Internal.Unsafe ( Data/Text/Internal/Unsafe.hs, dist/build/Data/Text/Internal/Unsafe.o ) [13 of 43] Compiling Data.Text.Internal.Fusion.Common ( Data/Text/Internal/Fusion/Common.hs, dist/build/Data/Text/Internal/Fusion/Common.o ) [14 of 43] Compiling Data.Text.Array ( Data/Text/Array.hs, dist/build/Data/Text/Array.o ) [15 of 43] Compiling Data.Text.Internal.Unsafe.Char ( Data/Text/Internal/Unsafe/Char.hs, dist/build/Data/Text/Internal/Unsafe/Char.o ) [16 of 43] Compiling Data.Text.Internal ( Data/Text/Internal.hs, dist/build/Data/Text/Internal.o ) [17 of 43] Compiling Data.Text.Unsafe ( Data/Text/Unsafe.hs, dist/build/Data/Text/Unsafe.o ) [18 of 43] Compiling Data.Text.Internal.Private ( Data/Text/Internal/Private.hs, dist/build/Data/Text/Internal/Private.o ) [19 of 43] Compiling Data.Text.Internal.Fusion ( Data/Text/Internal/Fusion.hs, dist/build/Data/Text/Internal/Fusion.o ) [20 of 43] Compiling Data.Text.Internal.Encoding.Fusion.Common ( Data/Text/Internal/Encoding/Fusion/Common.hs, dist/build/Data/Text/Internal/Encoding/Fusion/Common.o ) [21 of 43] Compiling Data.Text.Internal.Encoding.Utf8 ( Data/Text/Internal/Encoding/Utf8.hs, dist/build/Data/Text/Internal/Encoding/Utf8.o ) [22 of 43] Compiling Data.Text.Internal.Encoding.Fusion ( Data/Text/Internal/Encoding/Fusion.hs, dist/build/Data/Text/Internal/Encoding/Fusion.o ) [23 of 43] Compiling Data.Text.Internal.Lazy.Encoding.Fusion ( Data/Text/Internal/Lazy/Encoding/Fusion.hs, dist/build/Data/Text/Internal/Lazy/Encoding/Fusion.o ) [24 of 43] Compiling Data.Text.Internal.Search ( Data/Text/Internal/Search.hs, dist/build/Data/Text/Internal/Search.o ) [25 of 43] Compiling Data.Text ( Data/Text.hs, dist/build/Data/Text.o ) [26 of 43] Compiling Data.Text.Encoding ( Data/Text/Encoding.hs, dist/build/Data/Text/Encoding.o ) [27 of 43] Compiling Data.Text.Foreign ( Data/Text/Foreign.hs, dist/build/Data/Text/Foreign.o ) [28 of 43] Compiling Data.Text.Internal.IO ( Data/Text/Internal/IO.hs, dist/build/Data/Text/Internal/IO.o ) [29 of 43] Compiling Data.Text.IO ( Data/Text/IO.hs, dist/build/Data/Text/IO.o ) [30 of 43] Compiling Data.Text.Internal.Lazy ( Data/Text/Internal/Lazy.hs, dist/build/Data/Text/Internal/Lazy.o ) [31 of 43] Compiling Data.Text.Internal.Lazy.Fusion ( Data/Text/Internal/Lazy/Fusion.hs, dist/build/Data/Text/Internal/Lazy/Fusion.o ) [32 of 43] Compiling Data.Text.Internal.Lazy.Search ( Data/Text/Internal/Lazy/Search.hs, dist/build/Data/Text/Internal/Lazy/Search.o ) [33 of 43] Compiling Data.Text.Lazy.Internal ( Data/Text/Lazy/Internal.hs, dist/build/Data/Text/Lazy/Internal.o ) [34 of 43] Compiling Data.Text.Lazy ( Data/Text/Lazy.hs, dist/build/Data/Text/Lazy.o ) [35 of 43] Compiling Data.Text.Internal.Builder ( Data/Text/Internal/Builder.hs, dist/build/Data/Text/Internal/Builder.o ) [36 of 43] Compiling Data.Text.Lazy.Builder ( Data/Text/Lazy/Builder.hs, dist/build/Data/Text/Lazy/Builder.o ) [37 of 43] Compiling Data.Text.Internal.Builder.Functions ( Data/Text/Internal/Builder/Functions.hs, dist/build/Data/Text/Internal/Builder/Functions.o ) [38 of 43] Compiling Data.Text.Lazy.Builder.Int ( Data/Text/Lazy/Builder/Int.hs, dist/build/Data/Text/Lazy/Builder/Int.o ) [39 of 43] Compiling Data.Text.Lazy.IO ( Data/Text/Lazy/IO.hs, dist/build/Data/Text/Lazy/IO.o ) [40 of 43] Compiling Data.Text.Lazy.Read ( Data/Text/Lazy/Read.hs, dist/build/Data/Text/Lazy/Read.o ) [41 of 43] Compiling Data.Text.Lazy.Builder.RealFloat ( Data/Text/Lazy/Builder/RealFloat.hs, dist/build/Data/Text/Lazy/Builder/RealFloat.o ) ghc: panic! (the 'impossible' happened) (GHC version 7.8.4 for i386-unknown-linux): RegAlloc.Liveness.computeLivenss SCCs aren't in reverse dependent order bad blockId c8xHd [NONREC c8xHG: jmp *-4(%ebx), NONREC c8xHF: movl $12,828(%ebx) jmp *stg_gc_unpt_r1@got(%vI_n8Wmo), NONREC c8xHE: movl %vI_n8Wmo,%vI_n8WmH addl $sat_s8qTs{v}_info@gotoff,%vI_n8WmH movl %vI_n8WmH,-8(%edi) movl 4(%ebp),%vI_n8WmI movl %vI_n8WmI,-4(%edi) movl 16(%ebp),%vI_n8WmJ movl %vI_n8WmJ,(%edi) leal -7(%edi),%esi addl $20,%ebp jmp *(%ebp), NONREC c8xHz: movl $48,828(%ebx) movl %vI_n8Wmo,%vI_n8WmF addl $block{v c8xEh}_info@gotoff,%vI_n8WmF movl %vI_n8WmF,(%ebp) movl %vI_s8qTz,%esi movl %vI_s8qTx,4(%ebp) jmp *stg_gc_unbx_r1@got(%vI_n8Wmo), NONREC c8xHq: movl %vI_c8xEw,%esi incl 8(%ebp) addl $8,%ebp jmp *stg_ap_n_fast@got(%vI_n8Wmo), NONREC c8xHp: movl %vI_c8xEw,%esi addl $8,%ebp jmp *stg_ap_n_fast@got(%vI_n8Wmo), NONREC c8xHi: jmp *(%esi), NONREC c8xGZ: call 1f 1: popl %vI_n8Wmo addl $_GLOBAL_OFFSET_TABLE_+(.-1b), %vI_n8Wmo movl 4(%ebp),%vI_c8xEw movl %esi,%vI_n8Wmw andl $3,%vI_n8Wmw cmpl $2,%vI_n8Wmw jae _c8xHp jmp _c8xHq, NONREC c8xHy: movl %vI_n8Wmo,%vI_n8Wmy addl $lvl65{v s8qTB}_info@gotoff,%vI_n8Wmy movl %vI_n8Wmy,-44(%edi) movl %vI_s8qTz,-36(%edi) movl %vI_n8Wmo,%vI_n8WmA addl $a28{v s8qTD}_info@gotoff,%vI_n8WmA movl %vI_n8WmA,-32(%edi) movl %vI_s8qTd,-28(%edi) movl %vI_s8qTh,-24(%edi) movl %vI_s8qTk,-20(%edi) movl %vI_s8qTx,-16(%edi) leal -44(%edi),%vI_c8xEn movl %vI_c8xEn,-12(%edi) movl %vI_s8qRK,-8(%edi) movl %vI_s8qTj,-4(%edi) movl %vI_s8qTz,(%edi) movl %vI_n8Wmo,%vI_n8WmC addl $block{v c8xGZ}_info@gotoff,%vI_n8WmC movl %vI_n8WmC,16(%ebp) movl %vI_c8xEn,%esi leal -30(%edi),%vI_n8WmD movl %vI_n8WmD,20(%ebp) addl $16,%ebp testl $3,%esi jne _c8xGZ jmp _c8xHi, NONREC c8xGX: addl $12,%edi cmpl 804(%ebx),%edi ja _c8xHF jmp _c8xHE, NONREC c8xEi: addl $48,%edi cmpl 804(%ebx),%edi ja _c8xHz jmp _c8xHy, NONREC c8xHe: movl %esi,%vI_s8qTx movl $65533,%vI_s8qTz jmp _c8xEi, NONREC c8xEh: call 1f 1: popl %vI_n8Wmo addl $_GLOBAL_OFFSET_TABLE_+(.-1b), %vI_n8Wmo movl 20(%ebp),%vI_s8qRK movl 12(%ebp),%vI_s8qTd movl 16(%ebp),%vI_s8qTh movl 24(%ebp),%vI_s8qTj movl 8(%ebp),%vI_s8qTk movl 4(%ebp),%vI_s8qTx movl %esi,%vI_s8qTz jmp _c8xEi, NONREC c8xEb: jmp *(%esi), NONREC c8xEa: call 1f 1: popl %vI_n8Wmo addl $_GLOBAL_OFFSET_TABLE_+(.-1b), %vI_n8Wmo movl 20(%ebp),%vI_s8qRK movl 12(%ebp),%vI_s8qTd movl 16(%ebp),%vI_s8qTh movl 24(%ebp),%vI_s8qTj movl 8(%ebp),%vI_s8qTk movl 4(%ebp),%vI_s8qTw movl %vI_s8qTw,%vI_n8Wms andl $2095104,%vI_n8Wms cmpl $55296,%vI_n8Wms jne _c8xHd jmp _c8xHe, NONREC c8xE6: jmp *(%esi), NONREC c8xE5: call 1f 1: popl %vI_n8Wmo addl $_GLOBAL_OFFSET_TABLE_+(.-1b), %vI_n8Wmo movl %vI_n8Wmo,%vI_n8Wmq addl $block{v c8xEa}_info@gotoff,%vI_n8Wmq movl %vI_n8Wmq,(%ebp) movl 3(%esi),%vI_s8qTw movl 4(%ebp),%esi movl %vI_s8qTw,4(%ebp) testl $3,%esi jne _c8xEa jmp _c8xEb, NONREC c8xGW: movl %vI_n8Wmo,%vI_n8Wmu addl $block{v c8xE5}_info@gotoff,%vI_n8Wmu movl %vI_n8Wmu,-8(%ebp) movl %esi,%vI_s8qTk movl 6(%esi),%vI_s8qTu movl 2(%esi),%esi movl %vI_s8qTu,-4(%ebp) movl %vI_s8qTk,(%ebp) addl $-8,%ebp testl $3,%esi jne _c8xE5 jmp _c8xE6, NONREC c8xDC: jmp *(%esi), NONREC c8xDB: call 1f 1: popl %vI_n8Wmo addl $_GLOBAL_OFFSET_TABLE_+(.-1b), %vI_n8Wmo movl %esi,%vI_n8Wmn andl $3,%vI_n8Wmn cmpl $2,%vI_n8Wmn jae _c8xGW jmp _c8xGX, NONREC c8xHH: movl %vI_n8Wmo,%vI_n8WmL addl $block{v c8xDB}_info@gotoff,%vI_n8WmL movl %vI_n8WmL,-12(%ebp) movl %esi,%vI_s8qTh movl 2(%esi),%vI_s8qTd movl 6(%esi),%vI_s8qRK movl (%ebp),%esi movl %vI_s8qTd,-8(%ebp) movl %vI_s8qTh,-4(%ebp) movl %vI_s8qRK,(%ebp) addl $-12,%ebp testl $3,%esi jne _c8xDB jmp _c8xDC, NONREC c8xGY: call 1f 1: popl %vI_n8Wmo addl $_GLOBAL_OFFSET_TABLE_+(.-1b), %vI_n8Wmo leal -20(%ebp),%vI_n8Wml cmpl 796(%ebx),%vI_n8Wml jb _c8xHG jmp _c8xHH] }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10187> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10173: Panic: Irrefutable pattern failed for pattern Data.Maybe.Just
by GHC 15 Feb '19

15 Feb '19

#10173: Panic: Irrefutable pattern failed for pattern Data.Maybe.Just -----------------------------------+--------------------------------------- Reporter: mietek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.4 Keywords: | Operating System: Linux Architecture: x86 | Type of failure: Compile-time crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -----------------------------------+--------------------------------------- On 32-bit Red Hat Enterprise Linux 6.5, released on 11/11/2014 (available on [https://aws.amazon.com/marketplace/pp/B007NMF9O0/ Amazon EC2]), building `attoparsec-0.12.1.2` with GHC 7.8.4 causes a panic: {{{ Configuring attoparsec-0.12.1.2... Building attoparsec-0.12.1.2... Preprocessing library attoparsec-0.12.1.2... [ 1 of 21] Compiling Data.Attoparsec.Text.FastSet ( Data/Attoparsec/Text/FastSet.hs, dist/dist-sandbox- a9165fb6/build/Data/Attoparsec/Text/FastSet.o ) [ 2 of 21] Compiling Data.Attoparsec.Text.Buffer ( Data/Attoparsec/Text/Buffer.hs, dist/dist-sandbox- a9165fb6/build/Data/Attoparsec/Text/Buffer.o ) [ 3 of 21] Compiling Data.Attoparsec.Internal.Fhthagn ( Data/Attoparsec/Internal/Fhthagn.hs, dist/dist-sandbox- a9165fb6/build/Data/Attoparsec/Internal/Fhthagn.o ) [ 4 of 21] Compiling Data.Attoparsec.ByteString.Buffer ( Data/Attoparsec/ByteString/Buffer.hs, dist/dist-sandbox- a9165fb6/build/Data/Attoparsec/ByteString/Buffer.o ) [ 5 of 21] Compiling Data.Attoparsec.Zepto ( Data/Attoparsec/Zepto.hs, dist/dist-sandbox-a9165fb6/build/Data/Attoparsec/Zepto.o ) [ 6 of 21] Compiling Data.Attoparsec.Number ( Data/Attoparsec/Number.hs, dist/dist-sandbox-a9165fb6/build/Data/Attoparsec/Number.o ) [ 7 of 21] Compiling Data.Attoparsec.ByteString.FastSet ( Data/Attoparsec/ByteString/FastSet.hs, dist/dist-sandbox- a9165fb6/build/Data/Attoparsec/ByteString/FastSet.o ) [ 8 of 21] Compiling Data.Attoparsec.Internal.Types ( Data/Attoparsec/Internal/Types.hs, dist/dist-sandbox- a9165fb6/build/Data/Attoparsec/Internal/Types.o ) [ 9 of 21] Compiling Data.Attoparsec.Types ( Data/Attoparsec/Types.hs, dist/dist-sandbox-a9165fb6/build/Data/Attoparsec/Types.o ) [10 of 21] Compiling Data.Attoparsec.Internal ( Data/Attoparsec/Internal.hs, dist/dist-sandbox- a9165fb6/build/Data/Attoparsec/Internal.o ) [11 of 21] Compiling Data.Attoparsec.Combinator ( Data/Attoparsec/Combinator.hs, dist/dist-sandbox- a9165fb6/build/Data/Attoparsec/Combinator.o ) [12 of 21] Compiling Data.Attoparsec.ByteString.Internal ( Data/Attoparsec/ByteString/Internal.hs, dist/dist-sandbox- a9165fb6/build/Data/Attoparsec/ByteString/Internal.o ) [13 of 21] Compiling Data.Attoparsec.Text.Internal ( Data/Attoparsec/Text/Internal.hs, dist/dist-sandbox- a9165fb6/build/Data/Attoparsec/Text/Internal.o ) ghc: panic! (the 'impossible' happened) (GHC version 7.8.4 for i386-unknown-linux): compiler/nativeGen/RegAlloc/Linear/JoinToTargets.hs:84:13-59: Irrefutable pattern failed for pattern Data.Maybe.Just live_set }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10173> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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