diff --git a/src/libcollections/string.rs b/src/libcollections/string.rs
index 3c668f7fe9b..bb5345917e7 100644
--- a/src/libcollections/string.rs
+++ b/src/libcollections/string.rs
@@ -1052,6 +1052,7 @@ impl<T: fmt::Display + ?Sized> ToString for T {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl AsRef<str> for String {
+    #[inline]
     fn as_ref(&self) -> &str {
         self
     }
diff --git a/src/libcore/convert.rs b/src/libcore/convert.rs
index d3de77a9241..da6ac6bd752 100644
--- a/src/libcore/convert.rs
+++ b/src/libcore/convert.rs
@@ -173,6 +173,7 @@ impl<T> AsMut<[T]> for [T] {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl AsRef<str> for str {
+    #[inline]
     fn as_ref(&self) -> &str {
         self
     }