So, I recently played a game with Hamlet. I was doing a bunch of draw-to-X stuff, so all of my payload was disappearing and my hand size was often small. By the time I played my last Hamlet, I had just one card in hand. I discarded the last card in my hand to receive +action just because I felt like it, and then I was surprised to be presented with the option to "discard" for +buy. I tried, and it worked. I discarded nothing and still received a +buy.
Now I realize that this will practically never matter. I guess I could find an edge case where I Innovate something with +cards and draw up a Diadem and the combination of one extra coin and one extra buy allows me to buy something that I wouldn't otherwise, and maybe that wins me the game . . . but that's a stretch.
Still, it's not how the card should work, so I thought I'd report it.