G.4.3 Imaginary and complex
When a value of imaginary type is converted to a complex type, the real part of the complex result value is a positive zero and the imaginary part of the complex result value is determined by the conversion rules for the corresponding real types.
When a value of complex type is converted to an imaginary type, the real part of the complex value is discarded and the value of the imaginary part is converted according to the conversion rules for the corresponding real types.