I solved it in case of an interpreter with

  outer: loop {
    loop {
      let res = self.interpreter_loop(…);
      match res {
        Continue => {}
        Return => { break 'outer; }
        Exception => { break; }
      }
   }

I also made sure that the interpreter_loop call had an inline pragma, but that was otherwise a naive switch-case for the instructions. I didn’t find a way to make a template interpreter with safe Rust.