Afaik the borrow-checker is missing - please correct me if I am wrong - but that doesn't stop you from using it. You could very well use `rustc` for the borrow-checker and compile with GCC on any other backend. The borrow-checker only expresses that your code is sound according the rust spec.
Find the scope you can refer to the variable in, i.e. the curly brackets it is contained in. That variable is dropped right before the closing curly bracket. Things are dropped in reverse order of creation.
There's a rust front-end for gcc as well.