This one should be ready: <https://github.com/arro...

# arrow-contributors

[Jannis]

This one should be ready: https://github.com/arrow-kt/arrow/pull/1884
It changes monad, selective and applicative laws to use actual `Gen`'s rather than just Applicative.just for test data. This lead to a lot of failed tests, pretty much all of them were the recently added monad-applicative-consistency laws. I've fixed those in place. Now every applicative, by default evaluates the left effect first and then the right one. That is a good standart for arrow I think. The reason these were backwards in so many cases is likely because both haskell and cats define ap with a different argument order than arrow (they expect the f (A -> B) first wheres as we expect f a first). As applicative has no order semantics it does not matter which it is as long as it is consistent across the entire hierarchy, which is what these laws test. For readability I think it makes sense to have IO { println(1) }.ap(IO { { _: Unit -> println(2) } }) print 1 and then 2. (Which using only applicative methods is not guaranteed). This example with only a monad constraint would have printed 2 and then 1 before ^^ This is also the cause why traverse with different constraints could have caused different order on the returned collections.