Resolving dependencies...
Downloading PDBtools-0.0.2...
Configuring PDBtools-0.0.2...
Building PDBtools-0.0.2...
Preprocessing library PDBtools-0.0.2...
[1 of 4] Compiling PDButil.Vectors  ( PDButil/Vectors.hs, dist/build/PDButil/Vectors.o )

PDButil/Vectors.hs:36:18:
    Could not deduce (Eq a) arising from a use of `=='
    from the context (Floating a)
      bound by the type signature for
                 angle :: Floating a => [a] -> [a] -> a
      at PDButil/Vectors.hs:34:10-40
    Possible fix:
      add (Eq a) to the context of
        the type signature for angle :: Floating a => [a] -> [a] -> a
    In the first argument of `(||)', namely `norm a == 0'
    In the expression: norm a == 0 || norm b == 0
    In a stmt of a pattern guard for
                   an equation for `angle':
      norm a == 0 || norm b == 0
Failed to install PDBtools-0.0.2
cabal: Error: some packages failed to install:
PDBtools-0.0.2 failed during the building phase. The exception was:
ExitFailure 1