Add #[inline] to AsRef<str>::as_ref for String and str.

Author: koute

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
     }

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
     }