zlacker

Turing machines have a set of states and a transition function that governs how it moves between states. The transition function is a bunch of mappings like this:

    (input state, input symbol) --> (output state, output symbol, move left/right)

This is all static, so you can look at the transition table to see all the possible output symbols. If no transition has output symbol 1, then it never outputs 1. It doesn't matter how big the Turing machine is or what input it gets, it won't do it. This is basically trivial, but it's still a type of very simple static analysis that you can do. Similarly, if you don't have any states that halt, the machine will never halt.

This is like just not linking panic() into the program: it isn't going to be able to call it, no matter what else is in there.