Build failure: duplicate instance declarations

[deepfire]

these derivations will be built:
  /nix/store/n2gvnxy57zl05vbjz48c2dn6f0354f5w-testpack-2.1.3.0.drv
building path(s) ‘/nix/store/5fklm5z09jdk4qqsbr3a7wggj04ybns5-testpack-2.1.3.0’
setupCompilerEnvironmentPhase
Build with /nix/store/02hq0p02lf5aj342yb57sw1h2fg9sii0-ghc-8.0.0.20160421.
unpacking sources
unpacking source archive /nix/store/63xd8fgf5k1783vvwg9mcdy1l4qc1km0-testpack-2.1.3.0.tar.gz
source root is testpack-2.1.3.0
setting SOURCE_DATE_EPOCH to timestamp 1414447100 of file testpack-2.1.3.0/testpack.cabal
patching sources
Replace Cabal file with edited version from http://hackage.haskell.org/package/testpack-2.1.3.0
/revision/1.cabal.
Run jailbreak-cabal to lift version restrictions on build inputs.
compileBuildDriverPhase
setupCompileFlags: -package-db=/tmp/nix-build-testpack-2.1.3.0.drv-0/package.conf.d -j8 -thread
ed
[1 of 1] Compiling Main             ( Setup.hs, /tmp/nix-build-testpack-2.1.3.0.drv-0/Main.o )
Linking Setup ...
configuring
configureFlags: --verbose --prefix=/nix/store/5fklm5z09jdk4qqsbr3a7wggj04ybns5-testpack-2.1.3.0
 --libdir=$prefix/lib/$compiler --libsubdir=$pkgid --with-gcc=gcc --package-db=/tmp/nix-build-t
estpack-2.1.3.0.drv-0/package.conf.d --ghc-option=-optl=-Wl,-rpath=/nix/store/5fklm5z09jdk4qqsb
r3a7wggj04ybns5-testpack-2.1.3.0/lib/ghc-8.0.0.20160421/testpack-2.1.3.0 --enable-split-objs --
disable-library-profiling --disable-profiling --enable-shared --enable-library-vanilla --enable
-executable-dynamic --enable-tests
Configuring testpack-2.1.3.0...
Flags chosen: splitbase=True
Dependency HUnit -any: using HUnit-1.3.1.1
Dependency QuickCheck -any: using QuickCheck-2.8.2
Dependency base ==4.*: using base-4.9.0.0
Dependency containers -any: using containers-0.5.7.1
Dependency mtl -any: using mtl-2.2.1
Dependency random -any: using random-1.1
Using Cabal-1.24.1.0 compiled by ghc-8.0
Using compiler: ghc-8.0.0.20160421
Using install prefix:
/nix/store/5fklm5z09jdk4qqsbr3a7wggj04ybns5-testpack-2.1.3.0
Binaries installed in:
/nix/store/5fklm5z09jdk4qqsbr3a7wggj04ybns5-testpack-2.1.3.0/bin
Libraries installed in:
/nix/store/5fklm5z09jdk4qqsbr3a7wggj04ybns5-testpack-2.1.3.0/lib/ghc-8.0.0.20160421/testpack-2.
1.3.0
Private binaries installed in:
/nix/store/5fklm5z09jdk4qqsbr3a7wggj04ybns5-testpack-2.1.3.0/libexec
Data files installed in:
/nix/store/5fklm5z09jdk4qqsbr3a7wggj04ybns5-testpack-2.1.3.0/share/x86_64-linux-ghc-8.0.0.20160
421/testpack-2.1.3.0
Documentation installed in:
/nix/store/5fklm5z09jdk4qqsbr3a7wggj04ybns5-testpack-2.1.3.0/share/doc/x86_64-linux-ghc-8.0.0.2
0160421/testpack-2.1.3.0
Configuration files installed in:
/nix/store/5fklm5z09jdk4qqsbr3a7wggj04ybns5-testpack-2.1.3.0/etc
No alex found
Using ar found on system at:
/nix/store/s0kpgl8a101lkymj599f5a04s4wflf5s-binutils-2.26-dev/bin/ar
No c2hs found
No cpphs found
Using gcc version 5.3.0 given by user at:
/nix/store/ix03iknfgyrx7421fppjdczd9r4sw7pz-gcc-wrapper-5.3.0/bin/gcc
Using ghc version 8.0.0.20160421 found on system at:
/nix/store/02hq0p02lf5aj342yb57sw1h2fg9sii0-ghc-8.0.0.20160421/bin/ghc
Using ghc-pkg version 8.0.0.20160421 found on system at:
/nix/store/02hq0p02lf5aj342yb57sw1h2fg9sii0-ghc-8.0.0.20160421/bin/ghc-pkg
No ghcjs found
No ghcjs-pkg found
No greencard found
Using haddock version 2.17.0 found on system at:
/nix/store/02hq0p02lf5aj342yb57sw1h2fg9sii0-ghc-8.0.0.20160421/bin/haddock
No happy found
Using haskell-suite found on system at: haskell-suite-dummy-location
Using haskell-suite-pkg found on system at: haskell-suite-pkg-dummy-location
No hmake found
Using hpc version 0.67 found on system at:
/nix/store/02hq0p02lf5aj342yb57sw1h2fg9sii0-ghc-8.0.0.20160421/bin/hpc
Using hsc2hs version 0.68 found on system at:
/nix/store/02hq0p02lf5aj342yb57sw1h2fg9sii0-ghc-8.0.0.20160421/bin/hsc2hs
Using hscolour version 1.24 found on system at:
/nix/store/0ldw1mdnisdch7d7pwiv50dy5v5mbn5n-hscolour-1.24/bin/HsColour
No jhc found
Using ld found on system at:
/nix/store/ix03iknfgyrx7421fppjdczd9r4sw7pz-gcc-wrapper-5.3.0/bin/ld
No lhc found
No lhc-pkg found
No pkg-config found
Using strip version 2.26 found on system at:
/nix/store/s0kpgl8a101lkymj599f5a04s4wflf5s-binutils-2.26-dev/bin/strip
Using tar found on system at:
/nix/store/acikdr9h8d0jmrjxfyyh6mnh8dznqv8a-gnutar-1.28/bin/tar
No uhc found
building
Building testpack-2.1.3.0...
Preprocessing library testpack-2.1.3.0...
[1 of 3] Compiling Test.QuickCheck.Instances ( src/Test/QuickCheck/Instances.hs, dist/build/Test/QuickCheck/Instances.o )

src/Test/QuickCheck/Instances.hs:31:10: error:
    Duplicate instance declarations:
      instance (Arbitrary k, Arbitrary v, Eq k, Ord k) =>
               Arbitrary (Map.Map k v)
        -- Defined at src/Test/QuickCheck/Instances.hs:31:10
      instance [safe] (Ord k, Arbitrary k, Arbitrary v) =>
                      Arbitrary (Map.Map k v)
        -- Defined in ‘Test.QuickCheck.Arbitrary’

src/Test/QuickCheck/Instances.hs:36:10: error:
    Duplicate instance declarations:
      instance (CoArbitrary k, CoArbitrary v, Eq k, Ord k) =>
               CoArbitrary (Map.Map k v)
        -- Defined at src/Test/QuickCheck/Instances.hs:36:10
      instance [safe] (CoArbitrary k, CoArbitrary v) =>
                      CoArbitrary (Map.Map k v)
        -- Defined in ‘Test.QuickCheck.Arbitrary’
note: keeping build directory ‘/tmp/nix-build-testpack-2.1.3.0.drv-3’
builder for ‘/nix/store/n2gvnxy57zl05vbjz48c2dn6f0354f5w-testpack-2.1.3.0.drv’ failed with exit code 1
error: build of ‘/nix/store/n2gvnxy57zl05vbjz48c2dn6f0354f5w-testpack-2.1.3.0.drv’ failed