Iron compile error: traits

I have moved from writing my own rust code to modifying some one else’s. I am having a lot of what I expect are newbie problems. Here is the first:
The project I am working on uses iron and for various reasons I am playing around with bumping the version from 0.4 to 0.6

The error is ...trait bounds were not satisfied, mount::Mount : iron::Handler
Is that saying that Mount does not implement trait Iron::Handler? I cannot find that trait.

The error is:

  9147 |     let _ = server.http(WEB_URL).unwrap();
 10    |                    ^^^^
 11    |
 12    = note: the method `http` exists but the following trait bounds were not satisfied:
 13            `mount::Mount : iron::Handler`

WEB_URL is a constant static string reference (&'static str) The server is created using (edited to protect the guilty)…

let _ = router.get(...)
                .post(...);
let mut mount = Mount::new();
let _ = mount.mount("/", router);
Iron::new(mount)

It’s one of the reexports listed here.

reexport is new to me. I can not find anything about it in the docs. What is it?

https://doc.rust-lang.org/book/second-edition/ch14-02-publishing-to-crates-io.html#exporting-a-convenient-public-api-with-pub-use

It is odd that this feature is documented in the “Publishing to crates.io” section

I solved the problem by updating “mount” in Cargo.toml.

The versions ere inconsistent…