Make diagnostic methods dynamic on error

[charliermarsh]

Summary

I need these to accept "any error".

[konstin]

Looks good to me (i'll let andrew have the final word), i just wanted to note that this sounds a lot like the abstraction anyhow::Error builds.

[BurntSushi]

This LGTM. (What is the motivation?) This is the same way std::io::Error::other works: https://doc.rust-lang.org/std/io/struct.Error.html#method.other

You could use an anyhow::Error here, but the main advantage of that type is to build up a causal error chain. I think we're mostly doing that via thiserror, so I don't see much advantage to using it here.

[charliermarsh]

The motivation here is that I want to be able to pass in either Box<uv_diagnostic::Error> or Arc<uv_diagnostic::Error>... I can't clone, and I can't take a reference because I then need the type to be a field on the inner struct Error I create within these methods, and using a non-static lifetime gives me: non-static lifetimes are not allowed in the source of an error, because std::error::Error requires the source is dyn Error + 'static