Resolve For Assertions/Traits

[ajbeach]

I would like to add an extra argument to the resolver's findSingleExpression or to add a similar function that has a similar role but makes sure the result time satisfies a given trait.

As we take advantage of the trait system there are now language constructs that allow any type given that it satisfies some assertions (usually expressed as a built in trait). Although it can resolve these conditions in code there does not appear to be a way to do it from a keyword. If there is there is some code that should be updated.

I have run into this when creating throw and throwResume implementations and it has forced me to split up some passes into a pre- and a post-resolver component. I believe suspend also has some issue.

So far this hasn't actually prevented anything from working. If you add the right pre-resolver pass that converts things to functions you can still get it to work. However I believe this would simplify implementing language syntax that connects to traits.