Unusable with Data.Complex

[Abbath]

I want to use Data.Complex to do tricks like this:

ghci> (-5) ** 5 :: Complex (CReal 50)
-3125.0000000000000000 :+ 0.0000000000000000

But some functions from Data.Complex (log, sqrt) use magnitude, which uses scaleFloat and exponent from RealFloat. While scaleFloat works, exponent throws an error.

magnitude :: (RealFloat a) => Complex a -> a
magnitude (x:+y) =  scaleFloat k
                     (sqrt (sqr (scaleFloat mk x) + sqr (scaleFloat mk y)))
                    where k  = max (exponent x) (exponent y)
                          mk = - k
                          sqr z = z * z

I have tried changing exponent to

exponent _ = 0

and it works just fine, tests are passing.