First Draft: Static Single Assignment

[Walter Bright]

You're quite correct in that you can avoid const and immutable completely if you 
prefer. C and C++ have amply proven that.

Where they shine, however, is as compiler-enforced contracts restricting what 
can be done with data. I find them more and more useful the more complex and 
larger a program becomes.

`final` is in the same boat. `final` won't make your code run any faster or 
better. What it does do is tell the person reading the code that nobody is 
poking at it somewhere else in the function.