Function is

pub fn is<E: Error + 'static>(err: &(dyn Error + 'static)) -> bool

Returns whether the error source chain contains a given type.

Example

use std::io;

let err1 = io::Error::new(io::ErrorKind::Other, "boom");
assert!(errors::is::<io::Error>(&err1));

let err2 = errors::wrap("ruh roh", err1);
assert!(errors::is::<io::Error>(&err2));