Matthias Wchter wrote:
> If we want to be precise in the Unknown, maybe both versions should give 
> NaN for 0.arg and 0.0.arg (and Complex zero) as well?

and, while we are at it:

require 'complex'
p Complex.polar(0,   0/0.0)  # => expected: Complex(0,0)
p Complex.polar(0.0, 0/0.0)  # => expected: Complex(0.0,0.0)


but returns:
Complex(NaN,NaN)
Complex(NaN,NaN)

 Matthias