Okay, considering this one really carefully.

I think it would be best to call the selector with no try/catch and just let it blow up. Suppressing exceptions is a really scary thing to me. You're right about it being hard to throw a Slingshot or Dire exception at this point in the code.

The downside is that you lose the stack trace that caused an exception in the first place, but if your selector is still problematic to the point of causing an exception in its own right - its also got to be dealt with. Additionally, if we suppress the exception in a selector, no one can have handlers on selectors. ( don't think anyone would do this, but you never know how people are going to compose the constructs of a language like this.

I played around with it for a while at the REPL and preferred the exception coming out of the selector error and not being suppressed. That being said, I'm still open to being convinced about doing something different. We don't have to rush this.