0.11.0: Parser iterator item no longer implements Borrow?

[chriskrycho]

I use pulldown-cmark-to-cmark in a couple places, and it has a signature like so:

pub fn cmark<'a, I, E, F>(events: I, mut formatter: F) -> Result<State<'a>, fmt::Error>
where
    I: Iterator<Item = E>,
    E: Borrow<Event<'a>>,
    F: fmt::Write,
{
    ///
}

This was fine in 0.10.3, but no longer works with 0.11.0, because the item yielded by the iterator apparently no longer implements Borrow<Event<'a>>.

If this was intentional, that seems fine—the library will just need to update to account for the change! If so, would you be so kind as to document it as a breaking change in the release notes? 🙏🏼 (I poked around through the history a little but haven’t yet isolated where the change happened—only spent about five minutes doing that though.)

If it was unintentional, I am happy to help get a commit in so the items implement Borrow once again. (I am not blocked on this—I am just using 0.10.3 for the moment—but I do also have the time to contribute, so let me know!)

[ollpu]

As far as I can see, Borrow<Event> is still implemented for Event.

Is this because pulldown-cmark-to-cmark depends on v0.10.3, but you're trying to provide Events from the new version? If so, the library just needs an update.

I.e. the bound is really E: Borrow<pulldown_cmark{0.10}::Event> and you get a misleading error.

[chriskrycho]

Ah, interesting. That may well be, in which case the compiler error was (understandably!) misleading. I will patch the library on Monday and see if that is all it is! Thanks!