id
Make unique identifiers.
[]
= "0.1"
Usage
extern crate id;
...
let x = id!;
Each ID identifies a unique point in the source code, so you can't make more of them at runtime with a loop, nor with other such shenanigans.
License
Just take the code and do whatever you want with it, which I assume isn't much, because this library is pretty much useless.