I think it's a locust too. Looks like it's got suckers on the trunk. Definitely not a hickory b/c of the leaves. Bark is not dark or rough enough to be a walnut either, imo. I've got two small locusts in my yard, purchased, not wild that were here when we moved in. There are a several different varieties. This looks like mine.
I haven't seen any flowers on it at all, but I really haven't paid too much attention to it, it's in the very back of our yard. I will keep an eye out an maybe if it flowers it will help to id it. I was hoping it was a nut tree of some kind.