The ":" and "=>" are almost definitely superfluous, parsing "a: i32, b: 32" and "a, b: i32, c: i64" is no more difficult as parsing "a i32, b i32" and "a, b i32

The ":" and "=>" are almost definitely superfluous, parsing "a: i32, b: 32" and "a, b: i32, c: i64" is no more difficult as parsing "a i32, b i32" and "a, b i32, c i64". The same is true for colons in Python: they're not really necessary but provide slighlty better readability plus syntax highlighters can get away with using regexes, I guess.