PersistError is private

[sourcefrog]

This seems to make it hard to match on errors from persist, or perhaps my Rust is just not strong enough?

I want to write

    if let tempfile::PersistError(e) = f.persist_noclobber(path) {
        return Err(e.error);
    };

[sourcefrog]

Actually, my example code is a bit wrong, and apparently you can access fields in a pub but non-exported type. This works:

    if let Err(e) = f.persist_noclobber(path) {
        return Err(e.error);
    };  

So, close if you want.

However exposing it would let it get into the docs, and let callers declare a variable to hold it.