2 Checks for an iterator or string search (such as `find()`,
3 `position()`, or `rposition()`) followed by a call to `is_some()` or `is_none()`.
6 Readability, this can be written more concisely as:
7 * `_.any(_)`, or `_.contains(_)` for `is_some()`,
8 * `!_.any(_)`, or `!_.contains(_)` for `is_none()`.
13 vec.iter().find(|x| **x == 0).is_some();
15 "hello world".find("world").is_none();
21 vec.iter().any(|x| *x == 0);
23 !"hello world".contains("world");