As extra credit, I'd love to see an interactive editor which remembers how you went about disambiguating calls so as to warn you when the assumptions that lead to a choice change. For example, if you chose to use X and Y together in some way and the list of things you can do with an X and Y changes, then you might want to select a different choice.

Yeah there's a lot of potential for that kind of automatic support for a language that benefits from it. Something you could never do with a text editor!