Rollup merge of rust-lang#107464 - WaffleLapkin:all_that_remains_of_l…

…ines, r=dtolnay

Add `str::Lines::remainder`

Based on rust-lang#98453.

This PR adds `str::Lines::remainder` similarly to [other remainder function on str split iterators](rust-lang#77998).

library/core/src/str/iter.rs

@@ -1187,6 +1187,31 @@ impl<'a> DoubleEndedIterator for Lines<'a> {
 #[stable(feature = "fused", since = "1.26.0")]
 impl FusedIterator for Lines<'_> {}
 
+impl<'a> Lines<'a> {
+ /// Returns the remaining lines of the split string.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(str_lines_remainder)]
+ ///
+ /// let mut lines = "a\nb\nc\nd".lines();
+ /// assert_eq!(lines.remainder(), Some("a\nb\nc\nd"));
+ ///
+ /// lines.next();
+ /// assert_eq!(lines.remainder(), Some("b\nc\nd"));
+ ///
+ /// lines.by_ref().for_each(drop);
+ /// assert_eq!(lines.remainder(), None);
+ /// ```
+ #[inline]
+ #[must_use]
+ #[unstable(feature = "str_lines_remainder", issue = "77998")]
+ pub fn remainder(&self) -> Option<&'a str> {
+ self.0.iter.remainder()
+ }
+}
+
 /// Created with the method [`lines_any`].
 ///
 /// [`lines_any`]: str::lines_any