The typo mistake and the "forget parens" mistake are quite different in quality, though. If I mean method call, it is very unlikely that I would forget the parens in a language that always has parens for method calls.
"If I mean method call, it is very unlikely that I would forget the parens in a language that always has parens for method calls."
If I mean instance variable, it is very unlikely that I would forget the @ in a language that always has an @ for instance variables. :-\
Maybe I'm missing something, but I don't see a fundamental distinction between the two purely on the basis of consistency. I think an argument could be made that the parens on a method are a more meaningful and representative syntax element than an @ on an instance variable, making it easier to remember. Then again, someone could argue that braces are a more meaningful syntax element than indentation, and we all know how that goes. :-)
