Panic: Irrefutable pattern failed for pattern Data.Maybe.Just

On 32-bit Red Hat Enterprise Linux 6.5, released on 11/11/2014 (available on 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

Trac metadata

Trac field	Value
Version	7.8.4
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture