March 2018 - ghc-tickets

Re: [GHC] #2207: Load the interface details for GHC.* even without -O
by GHC 26 Mar '18

26 Mar '18

#2207: Load the interface details for GHC.* even without -O -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: ⊥ Component: Compiler | Version: 6.8.2 Resolution: | Keywords: newcomers Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * keywords: => newcomers Comment: Might be interesting to try. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2207#comment:15> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2710: -main-is flag in {-# OPTIONS #-} pragma not fully supported
by GHC 26 Mar '18

26 Mar '18

#2710: -main-is flag in {-# OPTIONS #-} pragma not fully supported -------------------------------------+------------------------------------- Reporter: Stephan202 | Owner: (none) Type: bug | Status: closed Priority: lowest | Milestone: Component: Compiler | Version: 6.8.3 Resolution: wontfix | Keywords: -main-is ghc Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: #1312 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: infoneeded => closed * resolution: => wontfix Comment: Seeing as there have been no objections in three years I'm going to close this. I've opened #14979 to track the warning. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2710#comment:18> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14979: Issue warning is -main-is is used in OPTIONS pragma
by GHC 26 Mar '18

26 Mar '18

#14979: Issue warning is -main-is is used in OPTIONS pragma -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #2710 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- #2710 notes that `-main-is` does not currently work in an `OPTIONS` pragma. However, in thomie and my opinion `-main-is`, `-rtsopts`, the various way options (e.g. `-debug`, `-prof`, etc.), etc. have no sensible interpretation in this context. I suggest that they should be ignored and we should throw a warning when they are encountered. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14979> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14720: GHC 8.4.1-alpha regression with TypeInType
by GHC 26 Mar '18

26 Mar '18

#14720: GHC 8.4.1-alpha regression with TypeInType -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 8.4.1-alpha1 (Type checker) | Keywords: TypeInType | 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: -------------------------------------+------------------------------------- GHC 8.2.2 is able to typecheck this code: {{{#!hs {-# LANGUAGE AllowAmbiguousTypes #-} {-# LANGUAGE DefaultSignatures #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE TypeInType #-} {-# LANGUAGE TypeOperators #-} module SGenerics where import Data.Kind (Type) import Data.Type.Equality ((:~:)(..), sym, trans) import Data.Void data family Sing (z :: k) class Generic (a :: Type) where type Rep a :: Type from :: a -> Rep a to :: Rep a -> a class PGeneric (a :: Type) where type PFrom (x :: a) :: Rep a type PTo (x :: Rep a) :: a class SGeneric k where sFrom :: forall (a :: k). Sing a -> Sing (PFrom a) sTo :: forall (a :: Rep k). Sing a -> Sing (PTo a :: k) class (PGeneric k, SGeneric k) => VGeneric k where sTof :: forall (a :: k). Sing a -> PTo (PFrom a) :~: a sFot :: forall (a :: Rep k). Sing a -> PFrom (PTo a :: k) :~: a data Decision a = Proved a | Disproved (a -> Void) class SDecide k where (%~) :: forall (a :: k) (b :: k). Sing a -> Sing b -> Decision (a :~: b) default (%~) :: forall (a :: k) (b :: k). (VGeneric k, SDecide (Rep k)) => Sing a -> Sing b -> Decision (a :~: b) s1 %~ s2 = case sFrom s1 %~ sFrom s2 of Proved (Refl :: PFrom a :~: PFrom b) -> case (sTof s1, sTof s2) of (Refl, Refl) -> Proved Refl Disproved contra -> Disproved (\Refl -> contra Refl) }}} But GHC 8.4.1-alpha2 cannot: {{{ $ /opt/ghc/8.4.1/bin/ghc Bug.hs [1 of 1] Compiling SGenerics ( Bug.hs, Bug.o ) Bug.hs:44:52: error: • Could not deduce: PFrom a ~ PFrom a from the context: b ~ a bound by a pattern with constructor: Refl :: forall k (a :: k). a :~: a, in a lambda abstraction at Bug.hs:44:37-40 Expected type: PFrom a :~: PFrom b Actual type: PFrom a :~: PFrom a NB: ‘PFrom’ is a non-injective type family • In the first argument of ‘contra’, namely ‘Refl’ In the expression: contra Refl In the first argument of ‘Disproved’, namely ‘(\ Refl -> contra Refl)’ • Relevant bindings include contra :: (PFrom a :~: PFrom b) -> Void (bound at Bug.hs:44:15) s2 :: Sing b (bound at Bug.hs:40:9) s1 :: Sing a (bound at Bug.hs:40:3) (%~) :: Sing a -> Sing b -> Decision (a :~: b) (bound at Bug.hs:40:3) | 44 | Disproved contra -> Disproved (\Refl -> contra Refl) | ^^^^ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14720> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14441: GHC HEAD regression involving type families in kinds
by GHC 26 Mar '18

26 Mar '18

#14441: GHC HEAD regression involving type families in kinds -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 8.3 Keywords: TypeInType, | Operating System: Unknown/Multiple TypeFamilies | Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: #13790 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- In GHC 8.2.1, this file typechecks: {{{#!hs {-# LANGUAGE TemplateHaskell #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE TypeInType #-} module Bug where import Data.Kind type family Demote (k :: Type) :: Type type family DemoteX (a :: k) :: Demote k data Prox (a :: k) = P type instance Demote (Prox (a :: k)) = Prox (DemoteX a) $(return []) type instance DemoteX P = P }}} (Note that the `$(return [])` line is essential, as it works around #13790.) However, on GHC HEAD, this now fails: {{{ $ ~/Software/ghc/inplace/bin/ghc-stage2 Bug.hs [1 of 1] Compiling Bug ( Bug.hs, Bug.o ) Bug.hs:15:27: error: • Expected kind ‘Demote (Prox a0)’, but ‘P’ has kind ‘Prox a1’ • In the type ‘P’ In the type instance declaration for ‘DemoteX’ | 15 | type instance DemoteX P = P | ^ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14441> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13643: Core lint error with TypeInType and TypeFamilyDependencies
by GHC 26 Mar '18

26 Mar '18

#13643: Core lint error with TypeInType and TypeFamilyDependencies -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple InjectiveFamilies, TypeInType | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: 12102 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- In the code {{{#!hs {-# Language TypeFamilyDependencies #-} {-# Language RankNTypes #-} {-# Language KindSignatures #-} {-# Language DataKinds #-} {-# Language TypeInType #-} {-# Language GADTs #-} import Data.Kind (Type) data Code = I type family Interp (a :: Code) = (res :: Type) | res -> a where Interp I = Bool data T :: forall a. Interp a -> Type where MkNat :: T False instance Show (T a) where show _ = "MkNat" main = do print MkNat }}} but add `{-# Options_GHC -dcore-lint #-}` and we get the attached log from running `runghc /tmp/tPb2.hs > /tmp/tPb2.log`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13643> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14556: Core Lint error: Ill-kinded result in coercion
by GHC 26 Mar '18

26 Mar '18

#14556: Core Lint error: Ill-kinded result in coercion -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.3 Keywords: TypeInType | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #14554 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# Language UndecidableInstances, DataKinds, TypeOperators, KindSignatures, PolyKinds, TypeInType, TypeFamilies, GADTs, LambdaCase, ScopedTypeVariables #-} import Data.Kind import Data.Proxy data Fn a b where IdSym :: Fn Type Type type family (@@) (f::Fn k k') (a::k)::k' where IdSym @@ a = a data KIND = X | FNARR KIND KIND data TY :: KIND -> Type where ID :: TY (FNARR X X) FNAPP :: TY (FNARR k k') -> TY k -> TY k' data TyRep (kind::KIND) :: TY kind -> Type where TID :: TyRep (FNARR X X) ID TFnApp :: TyRep (FNARR k k') f -> TyRep k a -> TyRep k' (FNAPP f a) type family IK (kind::KIND) :: Type where IK X = Type IK (FNARR k k') = Fn (IK k) (IK k') type family IT (ty::TY kind) :: IK kind where IT ID = IdSym IT (FNAPP f x) = IT f @@ IT x zero :: TyRep X a -> IT a zero = undefined }}} which gives Core lint error when run with `ghci -ignore-dot-ghci -dcore- lint` (8.3.20171122) attached. It compiles fine with {{{#!hs zero :: TyRep X a -> IT a zero = zero }}} but fails with `zero = let x = x in x`. See #14554. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14556> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14024: typechecker tests T13594 T13822 tc269 failing in devel2 flavour
by GHC 26 Mar '18

26 Mar '18

#14024: typechecker tests T13594 T13822 tc269 failing in devel2 flavour -------------------------------------+------------------------------------- Reporter: duog | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Test Suite | 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: -------------------------------------+------------------------------------- The tests T13594 T13822 tc269 are failing for me with BuildFlavour=devel2. They pass with BuildFlavour=validate. I have had a brief look to see if I could fix, but this is beyond my current capabilities. There is a comment in tc269.hs saying that it doesn't typecheck, however that looks to be out of date? test output pasted below: {{{ =====> tc269(normal) 1 of 3 [0, 0, 0] cd "./typecheck/should_compile/tc269.run" && "/home/doug/ghc- dev/devel2/inplace/bin/ghc-stage2" -c tc269.hs -dcore-lint -dcmm-lint -no- user-package-db -rtsopts -fno-warn-missed-specialisations -fshow-warning- groups -fdiagnostics-color=never -fno-diagnostics-show-caret -dno-debug- output -fno-warn-incomplete-patterns Compile failed (exit code 1) errors were: ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.3.20170723 for x86_64-unknown-linux): ASSERT failed! in_scope InScope {k_aSm} tenv [aRJ :-> k_aSm[sk:2]] tenvFVs [aSg :-> k_aSg[tau:1], aSm :-> k_aSm[sk:2]] cenv [] cenvFVs [] tys [k_aRJ[sk:1] -> *] cos [] Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1133:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1188:22 in ghc:Outputable assertPprPanic, called at compiler/types/TyCoRep.hs:2089:56 in ghc:TyCoRep checkValidSubst, called at compiler/types/TyCoRep.hs:2122:29 in ghc:TyCoRep substTy, called at compiler/typecheck/TcCanonical.hs:673:36 in ghc:TcCanonical 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/utils/Outputable.hs:1186:5 in ghc:Outputable assertPprPanic, called at compiler/types/TyCoRep.hs:2089:56 in ghc:TyCoRep checkValidSubst, called at compiler/types/TyCoRep.hs:2122:29 in ghc:TyCoRep substTy, called at compiler/typecheck/TcCanonical.hs:673:36 in ghc:TcCanonical Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug *** unexpected failure for tc269(normal) =====> T13594(normal) 2 of 3 [0, 1, 0] cd "./typecheck/should_compile/T13594.run" && "/home/doug/ghc- dev/devel2/inplace/bin/ghc-stage2" -c T13594.hs -dcore-lint -dcmm-lint -no-user-package-db -rtsopts -fno-warn-missed-specialisations -fshow- warning-groups -fdiagnostics-color=never -fno-diagnostics-show-caret -dno- debug-output -fno-warn-incomplete-patterns Compile failed (exit code 1) errors were: ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.3.20170723 for x86_64-unknown-linux): ASSERT failed! {$trModule = Module (TrNameS "main"#) (TrNameS "Bug"#), !x_a1o5 = (1, 2)} [x] Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1133:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1188:22 in ghc:Outputable assertPprPanic, called at compiler/deSugar/DsBinds.hs:89:71 in ghc:DsBinds 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/utils/Outputable.hs:1186:5 in ghc:Outputable assertPprPanic, called at compiler/deSugar/DsBinds.hs:89:71 in ghc:DsBinds Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug *** unexpected failure for T13594(normal) =====> T13822(normal) 3 of 3 [0, 2, 0] cd "./typecheck/should_compile/T13822.run" && "/home/doug/ghc- dev/devel2/inplace/bin/ghc-stage2" -c T13822.hs -dcore-lint -dcmm-lint -no-user-package-db -rtsopts -fno-warn-missed-specialisations -fshow- warning-groups -fdiagnostics-color=never -fno-diagnostics-show-caret -dno- debug-output -fno-warn-incomplete-patterns Compile failed (exit code 1) errors were: ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.3.20170723 for x86_64-unknown-linux): ASSERT failed! Bad coercion hole {a1bG}: (I (x_a19g |> Sym (Ty (Sym cobox))_N) |> D:R:IK[0]) (I (x_a19g |> Sym (Ty (Sym cobox))_N) |> D:R:IK[0]) nominal <(I (x_a19g |> Sym (Ty (Sym cobox))_N) |> D:R:IK[0])>_N I (x_a19g[ssk:3] |> Sym (Ty (Sym cobox))_N) I (x_a19g[ssk:3] |> Sym (Ty (Sym cobox))_N) nominal Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1133:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1188:22 in ghc:Outputable assertPprPanic, called at compiler/typecheck/TcMType.hs:304:105 in ghc:TcMType 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/utils/Outputable.hs:1186:5 in ghc:Outputable assertPprPanic, called at compiler/typecheck/TcMType.hs:304:105 in ghc:TcMType Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug *** unexpected failure for T13822(normal) Unexpected results from: TEST="T13594 T13822 tc269" }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14024> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14846: Renamer hangs (because of -XInstanceSigs?)
by GHC 26 Mar '18

26 Mar '18

#14846: Renamer hangs (because of -XInstanceSigs?) -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Keywords: InstanceSigs | Operating System: Unknown/Multiple TypeInType | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# Language RankNTypes, TypeInType, EmptyCase, GADTs, FlexibleInstances, ConstraintKinds, UndecidableInstances, AllowAmbiguousTypes, InstanceSigs #-} import Data.Kind import Data.Proxy type Cat ob = ob -> ob -> Type data Struct :: (k -> Constraint) -> Type where S :: Proxy (a::k) -> Struct (cls::k -> Constraint) type Structured a cls = (S ('Proxy :: Proxy a)::Struct cls) data AStruct :: Struct cls -> Type where AStruct :: cls a => AStruct (Structured a cls) class StructI (structured::Struct (cls :: k -> Constraint)) where struct :: AStruct structured instance (Structured xx cls ~ structured, cls xx) => StructI structured where struct :: AStruct (Structured xx cls) struct = AStruct data Hom :: Cat k -> Cat (Struct cls) where class Category (cat::Cat ob) where i :: StructI a => ríki a a instance Category ríki => Category (Hom ríki :: Cat (Struct cls)) where i :: forall a. StructI a => Hom ríki a a i = case struct :: AStruct (Structured a cls) of }}} Running on 8.2.1 and 8.5.20180105 both loop until interrupted {{{ $ ghci -ignore-dot-ghci 199.hs GHCi, version 8.5.20180105: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( 199.hs, interpreted ) ^CInterrupted. > > }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14846> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14705: ghc-iserv sometimes segfaults in profiled way
by GHC 26 Mar '18

26 Mar '18

#14705: ghc-iserv sometimes segfaults in profiled way -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Profiling | Version: 8.5 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Runtime crash Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I have seen a few testsuite failures due to `ghc-iserv` crashes like these, {{{ --- ./profiling/should_run/T5363.run/T5363.stdout.normalised 2018-01-22 18:57:49.401773263 +0000 +++ ./profiling/should_run/T5363.run/T5363.run.stdout.normalised 2018-01-22 18:57:49.401773263 +0000 @@ -1 +1 @@ -1250030000000 +ghc-stage2: ghc-iserv terminated (-7) *** unexpected failure for T5363(ghci-ext-prof) Actual stdout output differs from expected: --- ./profiling/should_run/scc001.run/scc001.stdout.normalised 2018-01-22 18:57:45.177724120 +0000 +++ ./profiling/should_run/scc001.run/scc001.run.stdout.normalised 2018-01-22 18:57:45.177724120 +0000 @@ -1,3 +1,3 @@ True 3 -'a' +ghc-stage2: ghc-iserv terminated (-11) *** unexpected failure for scc001(ghci-ext-prof) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14705> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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