Rust Conversion traits AsRef & AsMut
Example
std::convert::AsRef and std::convert::AsMut are used for cheaply converting types to references. For types A and B,
impl AsRef<B> for A
indicates that a &A can be converted to a &B and,
impl AsMut<B> for A
indicates that a &mut A can be converted to a &mut B.
This is useful for performing type conversions without copying or moving values. An example in the standard library is std::fs::File.open():
fn open<P: AsRef<Path>>(path: P) -> Result<File>
This allows File.open() to accept not only Path, but also OsStr, OsString, str, String, and PathBuf with implicit conversion because these types all implement AsRef<Path>.
