Minor fixes

[sftse]

Some of the commits in PR #68 I think are valuable on their own, I've extracted them into this PR, and added intermediate steps to justify the changes. As I was doing this, I saw some other issues, and added fixes for that as well.

[mdecimus]

Hi, the lifetimes fixes are fine but I am not ready to review #68 as it might break some tests upstream.

[sftse]

I'm aware and think it is good not to merge #68 as-is without in-depth testing.
I extracted those commits from #68 that have no observable external behavior changes. Commit d4e8362 has an inline assert that exhaustively checks that the logic expressions are equivalent. When the tests are run while that commit is checked out, this demonstrates equivalence. The assert is triggered at least once when running the tests, as can be observed by negating it, it will panic.

All other commits have been structured so their correctness is as obvious as can be from looking at the diff. I've pushed some formatting tweaks to make the diffs even smaller.