Serhiy Storchaka firstname.lastname@example.org added the comment:
The Imaginary type could help to solve other "gotchas". For example, in Python
complex(0, float('inf')) * 1
But in C++ you will get the real component 0, because multiplication of complex and real numbers is component wise.
With the Imaginary type we could get that 1j * x == complex(0, x) for all float x, including infinity and NaN.
Returning to the repr, the other way to correctly represent the repr of complex(-0.0, 1.0) is writing it as "-(0.0-1j)", but it looks unnatural to me.