It would be very helpful if we could do something like:

new TypeBuilder('StateError').newInstance(['Blah blah blah']).asThrow();

This would also work, and might be better than the original suggestion I had:

new ThrowExpression(...)

I have a branch where this change is implemented as an asThrow method on ExpressionBuilder instances, but it wouldn't be difficult for me to just expose the _ThrowExpression class I created.

Thoughts on this? Can I go ahead and submit a PR, or was I too vague and need to clarify?

Thanks in advance.