Bug#879082: haskell-linear FTBFS: Duplicate instance declarations

[Adrian Bunk]

Source: haskell-linear
Version: 1.20.6-1
Severity: serious

https://buildd.debian.org/status/package.php?p=haskell-linear&suite=sid

...
Preprocessing library linear-1.20.6...
[ 1 of 22] Compiling Linear.Instances ( src/Linear/Instances.hs, dist-ghc/build/Linear/Instances.o )

src/Linear/Instances.hs:30:10: error:
    Duplicate instance declarations:
      instance (Hashable k, Eq k) => Apply (HashMap k)
        -- Defined at src/Linear/Instances.hs:30:10
      instance [safe] (Hashable k, Eq k) => Apply (HashMap k)
        -- Defined in `Data.Functor.Bind.Class'

src/Linear/Instances.hs:33:10: error:
    Duplicate instance declarations:
      instance (Hashable k, Eq k) => Bind (HashMap k)
        -- Defined at src/Linear/Instances.hs:33:10
      instance [safe] (Hashable k, Eq k) => Bind (HashMap k)
        -- Defined in `Data.Functor.Bind.Class'

src/Linear/Instances.hs:41:10: error:
    Duplicate instance declarations:
      instance Apply Complex -- Defined at src/Linear/Instances.hs:41:10
      instance [safe] Apply Complex
        -- Defined in `Data.Functor.Bind.Class'

src/Linear/Instances.hs:44:10: error:
    Duplicate instance declarations:
      instance Bind Complex -- Defined at src/Linear/Instances.hs:44:10
      instance [safe] Bind Complex
        -- Defined in `Data.Functor.Bind.Class'

src/Linear/Instances.hs:56:10: error:
    Duplicate instance declarations:
      instance Foldable1 Complex
        -- Defined at src/Linear/Instances.hs:56:10
      instance [safe] Foldable1 Complex
        -- Defined in `Data.Semigroup.Foldable.Class'

src/Linear/Instances.hs:60:10: error:
    Duplicate instance declarations:
      instance Traversable1 Complex
        -- Defined at src/Linear/Instances.hs:60:10
      instance [safe] Traversable1 Complex
        -- Defined in `Data.Semigroup.Traversable.Class'
/usr/share/cdbs/1/class/hlibrary.mk:147: recipe for target 'build-ghc-stamp' failed
make: *** [build-ghc-stamp] Error 1