Checking conditions with the IsNoneOr trait

The provided is_none_or method is a mirror to the core library's is_some_and method. It returns true if the option is a [None] or the option is [Some] and the value inside of it matches a predicate.

Examples

use is_none_or::IsNoneOr;

let x: Option<u32> = Some(2);
assert_eq!(x.is_none_or(|x| x > 1), true);

let x: Option<u32> = Some(0);
assert_eq!(x.is_none_or(|x| x > 1), false);

let x: Option<u32> = None;
assert_eq!(x.is_none_or(|x| x > 1), true);