Mosfet drain/source minimum voltage

[speedyrudolf]

Hi, everyone.
I have a very basic question. I have a couple mosfets in half-bridge configuration. I would like to know what could happen if I turned the mosfets on, but there was no current on either drain or source pins.
A basic circuit representation is as in the image attached. So, basically, both h-bridges are turned on by the same driver, but only one of them gets any voltage at all. What would happen to the mosfets when the opto-triac is switched off and the mosfet switched on?
Thanks in advance.

 

[FvM]

Would you mind to explain the purpose of the opto triacs in the shown circuit topology? Besides other problems, their current rating doesn't seem to fit the MOSFETs.

The schematic is somehow incomplete, it's not shown how the gate signals are generated and if they are referenced to the MOSFET source terminals as required. If so, there's no problem to switch the MOSFETs on and off. There's no minimum Vds for doing so, unlike a triac, they can conduct with zero or even negative Vds (at least up the substrate diode forward voltage).