You are right about optimizations, there are a lot of situations where type annotations could greatly help the compiler. I just do not have the feeling that per

You are right about optimizations, there are a lot of situations where type annotations could greatly help the compiler. I just do not have the feeling that performance optimizations in CPython are the reason for Guido's proposal. It rather seems to be motivated for development tooling. Is `for i in xrange(10000):` especially optimized in python at the moment? I doubt it and those low hanging fruits could be tackled with some explicit pattern matching. (I probably should do my homework now and dive into the python source code).