Iterating over the typetag inventory

[leftadjoint]

I'd like to be able to iterate over the typetag inventory in order to generate a JSON schema inclusive of all of my trait's impls as of link time.

Unfortunately this doesn't seem to be supported in typetag; inventory seems to explicitly support it.

A simple example that fails:

#[cfg(test)]
mod test {
    use serde::{Deserialize, Serialize};
    use typetag;

    #[typetag::serde]
    trait A {}

    #[derive(Serialize, Deserialize)]
    struct Y {}

    #[typetag::serde]
    impl A for Y {}

    #[derive(Serialize, Deserialize)]
    struct Z {}

    #[typetag::serde]
    impl A for Z {}

    #[test]
    fn test() {
        let x = typetag::inventory::iter::<Box<dyn A>>;
        for y in x {}
    }
}

This complains:

the trait bound `inventory::private::iter<Box<dyn reference::test::A>>: IntoIterator` is not satisfied
the following implementations were found:
  <inventory::private::iter<T> as IntoIterator>
required by `into_iter`rustcE0277

It seems that since the iterator is private, this might not be possible at the moment.

Is it possible to make the iterator part of the public API?

[dtolnay]

I would prefer not to add this into this crate's public API.

You should be able to directly use inventory yourself, with your own type for the registry entries.