Single post in up-vote post will show as voted, like "voted already" or "cleare

I support this. I've had it happen to me where I went to upvote a post I liked, but forgot I already had done so at some point and got the "you've already upvoted this post" warning/error screen/pop-up. It would be nice to be able to tell 100% what posts you have upvoted instead of trying to remember what posts you have upvoted. It becomes a bit hard if you upvote a lot of posts if you start forgetting what ones you have upvoted.