Yet another half-baked idea for working around the orphan rule

Some usage examples would really help me understand the proposal. Especially, it is not clear to me whether this addresses the main place where I tend to trip over the orphan rule:

// in a binary crate; `unix_path` and `rustix` are external libraries
use unix_path::Path;    // a concrete type
use rustix::path::Arg;  // a trait

// I'm not allowed to do this:
impl Arg for Path { /* ... */ }

// which means I have to have wrappers like this instead:
pub(crate) fn open_fd(path: &Path)
    -> Result<rustix::fd::OwnedFd, MyError> {
    rustix::fs::open(
        path.as_unix_str().as_bytes(), // <-- blech
        O_RDONLY, M_IGNORED
    )
        .map_err(Into::into)
}

What I want out of improvements to the orphan rule is a way to pass unix_path::Path objects directly to rustix::fs::open (and other APIs that take arguments with trait bound rustix::path::Arg) with no extra ceremony at each callsite. Does your proposal give us that?

(See my post in this older thread for more detail.)