There are some 'invisible' downsides to adding new features, which often get overlooked: - Tooling, code analysers, etc. have to be updated to understand the n

There are some 'invisible' downsides to adding new features, which often get overlooked: - Tooling, code analysers, etc. have to be updated to understand the new features. Tools which are dead or "finished" may stop working. - The possibility that someone might use a new feature can break guarantees that are relied upon by existing code. An obvious example would be adding try/catch to a language: in languages without this, a function call is guaranteed to either return control to us, or to run indefinitely. Libraries might rely on this to clean up file descriptors, etc. afterwards. Such libraries would be broken by the mere existence of try/catch; even if we never actually use it. That said, I'm a big fan of pattern-matching, so it would be nice to have in Python, rather than crude approximations like '{pattern1: A, pattern2: B, pattern3: C, ...}[myVal]'