There seems to be confusion in some minds about VMC/VFR and IMC/IFR. MC means Meteorological conditions, i.e. OUTSIDE the A/C. FR means Flight Rules, the way one operates the aircraft.
So one can fly IFR/VMC, VFR/VMC and IFR/IMC but not legally and certainly not safely VFR/IMC.
I do log my night time as IF, because I am not allowed to fly VFR at night in my neck of the woods. And I do operate the machine with sole reference to the flight instruments, notwithstanding a good lookout for other traffic on the North Sea..