///
/// # Examples
///
+/// The `..` syntax is a `RangeFull`:
+///
/// ```
/// assert_eq!((..), std::ops::RangeFull);
+/// ```
///
-/// // for i in .. {
-/// // println!("This errors because .. has no IntoIterator impl");
-/// // }
+/// It does not have an `IntoIterator` implementation, so you can't use it in a
+/// `for` loop directly. This won't compile:
///
+/// ```ignore
+/// for i in .. {
+/// // ...
+/// }
+/// ```
+///
+/// Used as a slicing index, `RangeFull` produces the full array as a slice.
+///
+/// ```
/// let arr = [0, 1, 2, 3];
/// assert_eq!(arr[ .. ], [0,1,2,3]); // RangeFull
/// assert_eq!(arr[ ..3], [0,1,2 ]);