September 2016 - ghc-tickets

[GHC] #12564: Type family in type pattern kind
by GHC 20 Feb '19

20 Feb '19

#12564: Type family in type pattern kind -------------------------------------+------------------------------------- Reporter: int-index | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 (Type checker) | Keywords: TypeInType, | Operating System: Unknown/Multiple TypeFamilies | Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I want to write a type family that is analogous to `!!` for lists but requires the index to be no bigger than the length of the list. Usually, in dependently typed languages finite sets are used for this purpose, here's an attempt to do so in Haskell: {{{#!haskell {-# LANGUAGE TypeInType, TypeFamilies, GADTs, TypeOperators #-} import Data.Kind data N = Z | S N type family Len (xs :: [a]) :: N where Len '[] = Z Len (_ ': xs) = S (Len xs) data Fin :: N -> Type where FZ :: Fin (S n) FS :: Fin n -> Fin (S n) type family At (xs :: [a]) (i :: Fin (Len xs)) :: a where At (x ': _) FZ = x At (_ ': xs) (FS i) = At xs i }}} It fails to compile with this error: {{{ FinAt.hs:16:3: error: • Illegal type synonym family application in instance: 'FZ • In the equations for closed type family ‘At’ In the type family declaration for ‘At’ }}} That's because the kind of the `FZ` pattern (first clause of `At`) has the kind `Fin (Len xs)` and the application of `Len` cannot reduce completely. `checkValidTypePat` then disallows the pattern, as it contains a type family application. I tried to suppress `checkValidTypePat` and the definition of `At` has compiled; however, it's of little use, since `At` doesn't reduce: {{{#!haskell x :: At '[Bool] FZ x = True }}} results in {{{ FinAt.hs:20:5: error: • Couldn't match expected type ‘At * ((':) * Bool ('[] *)) ('FZ 'Z)’ with actual type ‘Bool’ • In the expression: True In an equation for ‘x’: x = True }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12564> 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] #11786: Need -fno-print-explicit-runtime-reps to work on IfaceType, else RuntimeRep leaks
by GHC 14 Feb '19

14 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 14 Feb '19

14 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 14 Feb '19

14 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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[GHC] #9277: GHCi panic: Loading temp shared object failed: Symbol not found
by GHC 14 Feb '19

14 Feb '19

#9277: GHCi panic: Loading temp shared object failed: Symbol not found ----------------------------------+--------------------------------- Reporter: mietek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 7.8.2 Keywords: | Operating System: MacOS X Architecture: x86_64 (amd64) | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #9034, #8935 | ----------------------------------+--------------------------------- When given a Objective-C object file referencing a symbol available in a system framework, GHCi panics saying it can't find the symbol the object file relies on. {{{ $ cat >foo.m <<EOF #import <Foundation/Foundation.h> BOOL is_main_thread() { return [NSThread isMainThread]; } EOF }}} {{{ $ clang -c -o foo.o foo.m }}} {{{ $ ghci -v -framework Foundation foo.o GHCi, version 7.8.2: http://www.haskell.org/ghc/ :? for help Glasgow Haskell Compiler, Version 7.8.2, stage 2 booted by GHC version 7.6.3 Using binary package database: /opt/ghc-7.8.2/lib/ghc-7.8.2/package.conf.d/package.cache wired-in package ghc-prim mapped to ghc- prim-0.3.1.0-948744e1f99cc8bcc7c7d3ba60c7c2d8 wired-in package integer-gmp mapped to integer- gmp-0.5.1.0-dc47f6b546fc171f67a7f7d311684a99 wired-in package base mapped to base-4.7.0.0-a333addb6892f3cc2e6baa5ec782bd04 wired-in package rts mapped to builtin_rts wired-in package template-haskell mapped to template- haskell-2.9.0.0-ed6ecfb467e6936688bb20f968f702e1 wired-in package dph-seq not found. wired-in package dph-par not found. Hsc static flags: Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. *** gcc: /usr/bin/gcc -m64 -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/opt/ghc-7.8.2/lib/ghc-7.8.2/base-4.7.0.0 --print-file-name libiconv.dylib Loading package base ... linking ... done. Loading object (static) foo.o ... Created temporary directory: /var/folders/26/0tzj1txn0vb_0061l4z4rsmr0000gn/T/ghc36377_0 *** Linker: /usr/bin/gcc -m64 -fno-stack-protector -DTABLES_NEXT_TO_CODE -m64 -dynamiclib -o /var/folders/26/0tzj1txn0vb_0061l4z4rsmr0000gn/T/ghc36377_0/ghc36377_1.dylib foo.o -undefined dynamic_lookup -single_module -install_name '@rpath/ghc36377_1.dylib' -L/opt/ghc-7.8.2/lib/ghc-7.8.2/base-4.7.0.0 -Wl,-rpath -Wl,/opt/ghc-7.8.2/lib/ghc-7.8.2/base-4.7.0.0 -L/opt/ghc-7.8.2/lib/ghc-7.8.2/integer-gmp-0.5.1.0 -Wl,-rpath -Wl,/opt/ghc-7.8.2/lib/ghc-7.8.2/integer-gmp-0.5.1.0 -L/opt/ghc-7.8.2/lib/ghc-7.8.2/ghc-prim-0.3.1.0 -Wl,-rpath -Wl,/opt/ghc-7.8.2/lib/ghc-7.8.2/ghc-prim-0.3.1.0 -L/opt/ghc-7.8.2/lib/ghc-7.8.2/rts-1.0 -Wl,-rpath -Wl,/opt/ghc-7.8.2/lib/ghc-7.8.2/rts-1.0 -lHSbase-4.7.0.0-ghc7.8.2 -lHSinteger-gmp-0.5.1.0-ghc7.8.2 -lHSghc-prim-0.3.1.0-ghc7.8.2 -liconv *** Deleting temp files: Deleting: /var/folders/26/0tzj1txn0vb_0061l4z4rsmr0000gn/T/ghc36377_0/ghc36377_1.dylib *** Deleting temp dirs: Deleting: /var/folders/26/0tzj1txn0vb_0061l4z4rsmr0000gn/T/ghc36377_0 ghc: panic! (the 'impossible' happened) (GHC version 7.8.2 for x86_64-apple-darwin): Loading temp shared object failed: dlopen(/var/folders/26/0tzj1txn0vb_0061l4z4rsmr0000gn/T/ghc36377_0/ghc36377_1.dylib, 9): Symbol not found: _OBJC_CLASS_$_NSThread Referenced from: /var/folders/26/0tzj1txn0vb_0061l4z4rsmr0000gn/T/ghc36377_0/ghc36377_1.dylib Expected in: flat namespace in /var/folders/26/0tzj1txn0vb_0061l4z4rsmr0000gn/T/ghc36377_0/ghc36377_1.dylib Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} Note omitting `-framework Foundation` makes no difference to the output. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9277> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9370: large blowup in memory usage and time when doing parallel build of xmlhtml package
by GHC 08 Feb '19

08 Feb '19

#9370: large blowup in memory usage and time when doing parallel build of xmlhtml package -------------------------------------+------------------------------------- Reporter: carter | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- I've observed a blowup in ghc memory usage when invoked with parallel build flags. to reproduce {{{ cabal get xmlhtml-0.2.3.2 cabal install xmlhtml-0.2.3.2 --only-dependencies cd xmlhtml-0.2.3.2 }}} then {{{ cabal clean ; cabal configure --ghc-options="-j4" ; time cabal build -j4 -v3 }}} will take quite a while and use > 1gb of ram whereas {{{ cabal clean ; cabal configure --ghc-options="-j1 ; time cabal build -j1 -v3 }}} will use < 150mb of ram. Based upon the output of cabal build -j4 -v3, it looks like the parallel build is spending a lottt more time in the simplifier passes. I'm not sure what changes between the parallel and sequential builds to change this. I'll try to dig into this more in a few days, but recording this problem now before i forget. (though of course any insights would be appreciated) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9370> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8635: GHC optimisation flag ignored when importing a local module with derived type classes
by GHC 08 Feb '19

08 Feb '19

#8635: GHC optimisation flag ignored when importing a local module with derived type classes ------------------------------------+------------------------------------- Reporter: NeilMitchell | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Given Foo.hs and Bar.hs: {{{ module Foo where data Food = Food -- deriving Eq {-# OPTIONS_GHC -O2 -ddump-simpl #-} module Bar where import Foo bar :: Int -> Bool bar x = x == 72 }}} If I run: {{{ ghc --make Bar -fforce-recomp }}} I get (snipped): {{{ Bar.bar = \ (x_afk :: GHC.Types.Int) -> case x_afk of _ { GHC.Types.I# x1_alo -> case x1_alo of _ { __DEFAULT -> GHC.Types.False; 72 -> GHC.Types.True } } }}} `bar` now looks pretty well optimised. However, if I uncomment the `deriving Eq` I get: {{{ Bar.bar1 = GHC.Types.I# 72 Bar.bar2 = GHC.Classes.== @ GHC.Types.Int GHC.Classes.$fEqInt Bar.bar = \ (x_amD :: GHC.Types.Int) -> Bar.bar2 x_amD Bar.bar1 }}} Now `bar` looks like terrible code, using dictionaries, boxing etc. It seems adding `deriving` in the imported and unused module makes it ignore the optimisation level. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8635> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11822: Pattern match checker exceeded (2000000) iterations
by GHC 07 Feb '19

07 Feb '19

#11822: Pattern match checker exceeded (2000000) iterations -------------------------------------+------------------------------------- Reporter: j.waldmann | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc3 Keywords: | Operating System: Unknown/Multiple Architecture: x86_64 | Type of failure: Compile-time (amd64) | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- graphviz seems a nice benchmark (not too large, few dependencies) that highlights compiler performance problems on "trivial" source code (cf. https://hackage.haskell.org/package/graphviz-2999.18.0.2/docs/src /Data-GraphViz-Attributes-Complete.html#sameAttribute) Compilation of Compiling Data.GraphViz.Attributes.Colors.X11 and Data.GraphViz.Attributes.Values takes >= 1 second each, and the following happens: {{{ cabal install graphviz-2999.18.0.2 --allow-newer ... [17 of 31] Compiling Data.GraphViz.Attributes.Complete ( Data/GraphViz/Attributes/Complete.hs, dist/dist-sandbox- e6f2c124/build/Data/GraphViz/Attributes/Complete.o ) Data/GraphViz/Attributes/Complete.hs:1013:1: warning: Pattern match checker exceeded (2000000) iterations in an equation for ‘sameAttribute’. (Use -fmax-pmcheck-iterations=n to set the maximun number of iterations to n) }}} I do welcome that ghc emits this warning - I expect you want its occurence to be reported as a bug? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11822> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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