I found this surprising, and had to pause to think for a second or 2. How common is it in other OO languages to not need "self" to reference instance variables in instance methods? Personally, I don't recall ever seeing it done without "self". (Been so long since I last used C++ that I had forgotten.)

Java does this too. You can disambiguate (if you have a local variable of the same name), with this. For example, this.x.