rollup merge of #23580: nikomatsakis/pattern-and-overflow

1 files changed, 20 insertions, 0 deletions

diff --git a/src/libcollections/string.rs b/src/libcollections/string.rs
index 6463949ac8a..a5d788143b0 100644
--- a/src/libcollections/string.rs
+++ b/src/libcollections/string.rs
@@ -25,6 +25,7 @@ use core::mem;
 use core::ops::{self, Deref, Add, Index};
 use core::ptr;
 use core::slice;
+use core::str::Pattern;
 use unicode::str as unicode_str;
 use unicode::str::Utf16Item;
 
@@ -765,6 +766,25 @@ impl<'a> Extend<&'a str> for String {
     }
 }
 
+/// A convenience impl that delegates to the impl for `&str`
+impl<'a, 'b> Pattern<'a> for &'b String {
+    type Searcher = <&'b str as Pattern<'a>>::Searcher;
+
+    fn into_searcher(self, haystack: &'a str) -> <&'b str as Pattern<'a>>::Searcher {
+        self[..].into_searcher(haystack)
+    }
+
+    #[inline]
+    fn is_contained_in(self, haystack: &'a str) -> bool {
+        self[..].is_contained_in(haystack)
+    }
+
+    #[inline]
+    fn is_prefix_of(self, haystack: &'a str) -> bool {
+        self[..].is_prefix_of(haystack)
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl PartialEq for String {
     #[inline]