diff --git a/src/libcollections/str.rs b/src/libcollections/str.rs
index baef6ba6f01f3..198627ad2fc3a 100644
--- a/src/libcollections/str.rs
+++ b/src/libcollections/str.rs
@@ -396,6 +396,7 @@ macro_rules! utf8_acc_cont_byte {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Borrow<str> for String {
+    #[inline]
     fn borrow(&self) -> &str { &self[..] }
 }