correct dynamic pos

Review by @retronym

- I'm unable to assign tickets to me, could someone please activate my account for this (username on Jira is antoras)?
- I'm not completely sure about what positions have to be transparent. For example, I didn't make the parameters of `applyDynamicNamed` transparent because they occur in sources (but the created tuples do not). Thus, I'm not sure if this is correct.
- I used "complicated" DirectTests because I found no other way to react on positive compilation+check output