Was playing this with the wife yesterday and she went to cast volley as she hadn't used it before. At the time she had a melee weapon equipped and assumed it'd either tell her she couldn't successfully complete it or it would automatically switch to a ranged weapon beforehand (she hadn't yet used her once per turn weapon switch). It let her select the ability and bring up the aoe bubble but when she used it it just didn't do anything. There wasn't an error or failure message, it just paused for a second and then moved onto the next character.
I feel like the game should prevent this situation from occurring by greying out the ability unless an appropriately ranged weapon is equipped.