fix doctest

src/at_most_one.rs

@@ -6,7 +6,7 @@ use core::mem;
 /// elements in the iterator.
 /// 
 /// See [`.at_most_one()`](crate::Itertools::at_most_one) for more detail.
-#[derive(PartialEq, Eq, Clone)]
+#[derive(PartialEq, Eq, Clone, Debug)]
 pub enum AtMostOneResult<I: Iterator> {
     /// The iterator was empty and therefore had zero elements.
     Zero,
@@ -15,11 +15,11 @@ pub enum AtMostOneResult<I: Iterator> {
     One(I::Item),
 
     /// The iterator had more than one element. 
-    /// `MoreThanOne` is an iterator which yields the same elements as the original iterator.
+    /// [`MoreThanOne`](crate::MoreThanOne) is an iterator which yields the same elements as the original iterator. 
     MoreThanOne(MoreThanOne<I>),
 }
 
-#[derive(PartialEq, Eq, Clone)]
+#[derive(PartialEq, Eq, Clone, Debug)]
 enum IterSource<T> {
     FirstElement(T, T),
     SecondElement(T),
@@ -28,7 +28,7 @@ enum IterSource<T> {
 
 /// The iterator returned by [`.at_most_one()`](crate::Itertools::at_most_one), if the original iterator
 /// had at least two elements remaining. Yields the same elements as the original iterator.
-#[derive(PartialEq, Eq, Clone)]
+#[derive(PartialEq, Eq, Clone, Debug)]
 pub struct MoreThanOne<I: Iterator> {
     next_source: IterSource<I::Item>,
     inner: I,

src/lib.rs

@@ -3699,12 +3699,13 @@ pub trait Itertools : Iterator {
     ///
     /// This function is especially useful in `match` statements, to clearly assert the number of elements
     /// in an iterator or take different paths depending on this number. 
-    /// For example, using [`.find()`](std::iter::Iterator::find) will stop at the first element, 
+    /// For example, using [`.find()`](std::iter::Iterator::find) will stop at the first matched element, 
     /// but you may additionally want to validate that no more than a single element satisfies the predicate.
     /// 
     /// # Examples
     /// ```
-    /// use itertools::Itertools;
+    /// use itertools::{Itertools, AtMostOneResult};
+    /// use core::iter::{empty, once};
     /// 
     /// let numbers = [-9, -1, -7, 4, -38, -21].iter().copied();
     /// let positive_number: Option<i32> = match numbers.filter(|&num| num >= 0).at_most_one() {
@@ -3714,10 +3715,11 @@ pub trait Itertools : Iterator {
     /// };
     /// assert_eq!(positive_number, Some(4));
     /// 
-    /// let zero_elements = empty().at_most_one();
-    /// assert_eq!(zero_elements, AtMostOneResult::Zero);
+    /// let zero_elements = empty::<i32>().at_most_one();
+    /// assert!(matches!(zero_elements, AtMostOneResult::Zero));
     /// 
-    /// assert_eq!(one_element, AtMostOneResult::One(5));
+    /// let one_element = once(5).at_most_one();
+    /// assert!(matches!(one_element, AtMostOneResult::One(5)));
     /// 
     /// let many_elements = (1..=10).at_most_one();
     /// let AtMostOneResult::MoreThanOne(more_than_one) = many_elements else { panic!() };