> If your language is written in itself, and you make changes to it, you're changing the language in which your language is written. Mistakes in this can cause

> If your language is written in itself, and you make changes to it, you're changing the language in which your language is written. Mistakes in this can cause hair-pulling bugs. Fair, but, hold on, shouldn't you just make sure that if you're working on version 1.2 of your language, you compile it using your compiler from a stable 1.1 build? (other than maybe in tests where you need to test new features etc) This is not a problem specific to programming languages, but to any other system that uses part of itself