June 2016 - ghc-tickets

[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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[GHC] #12149: Support bit-fields
by GHC 05 Feb '19

05 Feb '19

#12149: Support bit-fields -------------------------------------+------------------------------------- Reporter: | Owner: facundo.dominguez | Type: bug | Status: new Priority: normal | Milestone: Component: hsc2hs | Version: 8.0.1 Keywords: bit-fields | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Having C type like: {{{ typedef struct S { int f0: 1; int f1: 15; } S; }}} and {{{hsc}}} code like {{{ #{peek S, f0} p }}} Causes {{{hsc2hs}}} to fail with {{{ error: attempt to take address of bit-field structure member 'f0' }}} Apparently this is an error from gcc, which cannot provide the address of bit-fields. However, in Haskell we are not interested in the address of the bit-field but in its value. It would be useful to have a way to get and set the values of these fields. Some former discussion [https://mail.haskell.org/pipermail/haskell- cafe/2008-November/050317.html here] -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12149> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10857: "ghci -XMonomorphismRestriction" doesn't turn on the monomorphism restriction
by GHC 04 Feb '19

04 Feb '19

#10857: "ghci -XMonomorphismRestriction" doesn't turn on the monomorphism restriction -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 7.10.1 Keywords: newcomer | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- Compare {{{ rwbarton@morphism:/tmp$ ghci-7.10.1 -XMonomorphismRestriction GHCi, version 7.10.1: http://www.haskell.org/ghc/ :? for help Prelude> let a = (+) Prelude> :t a a :: Num a => a -> a -> a }}} with {{{ rwbarton@morphism:/tmp$ ghci-7.10.1 GHCi, version 7.10.1: http://www.haskell.org/ghc/ :? for help Prelude> :set -XMonomorphismRestriction Prelude> let a = (+) Prelude> :t a a :: Integer -> Integer -> Integer }}} Confusing! This also occurred in 7.8. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10857> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9693: Reloading GHCi with Template Haskell names can panic GHC
by GHC 03 Feb '19

03 Feb '19

#9693: Reloading GHCi with Template Haskell names can panic GHC -------------------------------------+------------------------------------- Reporter: maxs | 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: GHC Blocked By: | rejects valid program Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- First, load the following program into GHCi. '''Fun.hs''' {{{#!hs module Fun where import Language.Haskell.TH stuff = do -- let x = mkName "X" x <- newName "X" sequence $ [dataD (return []) x [] [ normalC x [] ] []] }}} '''thbug.hs''' {{{#!hs {-# LANGUAGE TemplateHaskell #-} import Fun stuff }}} Then comment out the newName, un comment the mkName and reload GHCi. {{{ ghc: panic! (the 'impossible' happened) (GHC version 7.8.3 for x86_64-apple-darwin): kcLookupKind APromotionErr RecDataConPE Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} It is important to note this is a valid program, if you then close GHCi and start it again with the modified file, it will load correctly. Reloading after attempting to compile the newName version will cause a panic. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9693> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11084: Some type families don't reduce with :kind!
by GHC 03 Feb '19

03 Feb '19

#11084: Some type families don't reduce with :kind! -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 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: -------------------------------------+------------------------------------- Sadly, I'm unable to reproduce this without `singletons`. :( Observe: {{{ > ghci GHCi, version 7.10.2: http://www.haskell.org/ghc/ :? for help Prelude> import Data.Promotion.Prelude -- singletons-2.0.1 Prelude Data.Promotion.Prelude> :kind! Lookup 'True '[ '(True, True) ] Lookup 'True '[ '(True, True) ] :: Maybe Bool = Data.Singletons.Prelude.List.Case_1628035408 'True 'True 'True '[] (Data.Singletons.Apply (Data.Singletons.Apply (:==$) 'True) 'True) Prelude Data.Promotion.Prelude> :kind! Lookup 'True '[ '(True, True) ] Lookup 'True '[ '(True, True) ] :: Maybe Bool = JustSym1 'True }}} Note that the exact same command run twice yields different results. I tried peeking at `-ddump-tc-trace` but got nothing of use. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11084> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12001: RFC: Add pattern synonyms to base
by GHC 02 Feb '19

02 Feb '19

#12001: RFC: Add pattern synonyms to base -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: | Version: 7.10.3 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: -------------------------------------+------------------------------------- Since we have pattern synonyms it's worth considering if some belong in base: [https://hackage.haskell.org/package/lens-4.14/docs/Data-Complex-Lens.html Data.Complex.Lens] contains patterns that could be defined in base, here are some more suggestions: === Data.Array === {{{#!hs pattern ArrayIx :: Ix i => (i, i) -> [(i, e)] -> Array i e pattern ArrayIx low'high xs <- ((\arr -> (bounds arr, assocs arr)) -> (low'high, xs)) where ArrayIx low'high xs = array low'high xs }}} === Data.Bits === {{{#!hs pattern ZeroBits :: (Eq a, Bits a) => a pattern ZeroBits <- ((== zeroBits) -> True) where ZeroBits = zeroBits pattern BitSize :: Bits a => Int -> a pattern BitSize n <- (bitSizeMaybe -> Just n) pattern Signed :: Bits a => a pattern Signed <- (isSigned -> True) pattern Unsigned :: Bits a => a pattern Unsigned <- (isSigned -> False) pattern PopCount :: Bits a => Int -> a pattern PopCount n <- (popCount -> n) }}} === Data.Char === {{{#!hs pattern ControlChar :: Char pattern ControlChar <- (isControl -> True) pattern SpaceChar :: Char pattern SpaceChar <- (isSpace -> True) }}} === Data.Complex === {{{#!hs pattern Conjugate :: Num a => Complex a -> Complex a pattern Conjugate a <- (conjugate -> a) where Conjugate a = conjugate a pattern Polar :: RealFloat a => a -> a -> Complex a pattern Polar m theta <- (polar -> (m, theta)) where Polar m theta = mkPolar m theta -- See https://github.com/ekmett/lens/issues/653 pattern Real :: Num a => a -> Complex a pattern Real r <- r :+ _ where Real r = r :+ 0 pattern Imaginary :: Num a => a -> Complex a pattern Imaginary i <- _ :+ i where Imaginary i = 0 :+ i }}} === GHC.Float === {{{#!hs pattern NegativeZero :: RealFloat a => a pattern NegativeZero <- (isNegativeZero -> True) where NegativeZero = -0 pattern Denormalized :: RealFloat a => a pattern Denormalized <- (isDenormalized -> True) pattern NaN :: RealFloat a => a pattern NaN <- (isNaN -> True) where NaN = 0 / 0 -- How ever negative infinity is handled pattern Infinity :: RealFloat a => a pattern Infinity <- ((== 1 / 0) -> True) where Infinity = 1 / 0 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12001> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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