Rollup merge of #41249 - GuillaumeGomez:rustdoc-render, r=steveklabnik,frewsxcv

[rust.git] / src / libcollections / slice.rs

diff --git a/src/libcollections/slice.rs b/src/libcollections/slice.rs
index 3069adb12e92cd127c5bd29d03d266da23d49df4..7c3c825cfd1f5dc309980514d74af6b7203b6b12 100644 (file)
--- a/src/libcollections/slice.rs
+++ b/src/libcollections/slice.rs
@@ -1527,6 +1527,19 @@ fn to_owned(&self) -> Vec<T> {
     fn to_owned(&self) -> Vec<T> {
         panic!("not available with cfg(test)")
     }
+
+    fn clone_into(&self, target: &mut Vec<T>) {
+        // drop anything in target that will not be overwritten
+        target.truncate(self.len());
+        let len = target.len();
+
+        // reuse the contained values' allocations/resources.
+        target.clone_from_slice(&self[..len]);
+
+        // target.len <= self.len due to the truncate above, so the
+        // slice here is always in-bounds.
+        target.extend_from_slice(&self[len..]);
+    }
 }
 
 ////////////////////////////////////////////////////////////////////////////////