Function `request_ref`

fn request_ref<'a, T, impl Error + ?Sized: Error + ?Sized>(err: &'a impl Error + ?Sized) -> Option<&'a T>
where
    T: 'static + ?Sized

Requests a reference of type T from the given impl Error.

Examples

Get a string reference from an error.

#![feature(error_generic_member_access)]
use core::error::Error;
use core::error::request_ref;

fn get_str(err: &impl Error) -> &str {
    request_ref::<str>(err).unwrap()
}