Most wine is not good after being frozen, except for "Icewine," which is made from frozen grapes, usually Riesling.
Probably not the best
If the can has not buckled or become misshapen and you see no signs of leakage or seam failure, then the food will probably be OK.
Defrosted mashed potatoes can be safely eaten after defrosting, but I wouldn't call them "good." Potatoes lose their texture in freezing and defrosting.
It likely is not good anymore. Even frozen, the fats can become rancid.