refactor: moving AsIntoIter into into_iter.rs

library/alloc/src/vec/into_iter.rs

@@ -268,3 +268,18 @@ unsafe fn as_inner(&mut self) -> &mut Self::Source {
         self
     }
 }
+
+// internal helper trait for in-place iteration specialization.
+#[rustc_specialization_trait]
+pub(crate) trait AsIntoIter {
+    type Item;
+    fn as_into_iter(&mut self) -> &mut IntoIter<Self::Item>;
+}
+
+impl<T> AsIntoIter for IntoIter<T> {
+    type Item = T;
+
+    fn as_into_iter(&mut self) -> &mut IntoIter<Self::Item> {
+        self
+    }
+}

library/alloc/src/vec/mod.rs

@@ -93,6 +93,7 @@
 
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::into_iter::IntoIter;
+pub (crate) use self::into_iter::AsIntoIter;
 
 mod into_iter;
 
@@ -3019,18 +3020,3 @@ fn from(s: &str) -> Vec<u8> {
         Ok(array)
     }
 }
-
-// internal helper trait for in-place iteration specialization.
-#[rustc_specialization_trait]
-pub(crate) trait AsIntoIter {
-    type Item;
-    fn as_into_iter(&mut self) -> &mut IntoIter<Self::Item>;
-}
-
-impl<T> AsIntoIter for IntoIter<T> {
-    type Item = T;
-
-    fn as_into_iter(&mut self) -> &mut IntoIter<Self::Item> {
-        self
-    }
-}