[twic]

I suspect a similar analysis holds, though. After all, throw-catch style exceptions do involve resumption, just not at the point at which they're thrown. You have a similar challenge in making sure that you haven't left the world in an inconsistent state when an exception emerges from some code.

That said, i am skeptical that there is a significant safety practical difference between the use of checked exceptions, and the use of return values with a try! macro. In both cases, you are forced to acknowledge in the code that an exception can be thrown, which means that you have a chance to do the right thing about consistency.

We could imagine a version of checked exceptions where individual throw sites have to be tagged. A parallel universe version of Java [1] might look like:

  InputStream in = whatever();
  int b = in.read() throw IOException;

Wouldn't that be exactly isomorphic to Rust's use of try! ?

[1] No, not that Parallel Universe version of Java: http://blog.paralleluniverse.co/2014/05/01/modern-java/