[GR-17498] It is not possible to define complex number with minus.

[GR-20756] It is not possible divide complex number with integer.
[GR-20757] Div float by complex number gets wrong results.
[GR-20768] It is not possible to create complex number from string with brackets.
[GR-20777] The complex number can be created from two complex numbers.

Author: ppisl