I think this would require an `x.advanced(by: Stride, limitedBy: Self) -> Self?` customization point in `Strideable`, and for the `stride(to:by: )` and `stride(through:by: )` iterators to use it.

Not necessarily. It should be possible to check the distance to end before calling _step, and if it's less than stride simply return end.

Hi @gonzalolarralde, so that you're aware, I've got a PR that's pending a bit of revision which addresses this bug:

#34860

@xwu Thanks for the pointer! you saved me a ton of time 🙂 I was drafting a solution that looks similar in principle to yours to then try to figure out how to adapt it to make it fit the API stability story.
Counter-example showing `distance(to: )`'s limitation make it clear that this might look like a simpler issue in principle than what it really is. (striking after re-reading your comments in the PR)

Sure thing. I'll find some time to get the fix in my PR merged this week. I've been putting off updating the documentation comments but that can be done separately.

perfect, thanks @xwu . TBH I got into this issue because I was hoping to be able to use Strideable on a finite enum. Something like this would exemplify:

enum E : Int, Strideable {
  case one = 1, two, three, four
  func distance(to other: Self) -> Int {
    return other.rawValue - self.rawValue
  }
  func advanced(by n: Int) -> Self {
    return Self(rawValue: self.rawValue + n)!
  }
}

// current implementation requires this to past beyond `Test.four` to know it's finished.
print(Array(stride(from: Test.one, to: Test.four, by: 2)))

so I attempted a naive fix that I wanted to verify how could be translated into something stable to the current implementation's inline methods. It is available here: gonzalolarralde@b846dba

I opened SR-14325 to track the use-case I was hoping to enable, if you have any ideas/pointers on how a API-stable solution would look I would really appreciate your input!

Fixed in PR#34860.