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 6cff315a6ccd9eb28083d2b1f5b2afa9e8dc2430..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..]);
+    }
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -1558,7 +1571,7 @@ fn insert_head<T, F>(v: &mut [T], is_less: &mut F)
             //    performance than with the 2nd method.
             //
             // All methods were benchmarked, and the 3rd showed best results. So we chose that one.
-            let mut tmp = NoDrop { value: ptr::read(&v[0]) };
+            let mut tmp = mem::ManuallyDrop::new(ptr::read(&v[0]));
 
             // Intermediate state of the insertion process is always tracked by `hole`, which
             // serves two purposes:
@@ -1571,13 +1584,13 @@ fn insert_head<T, F>(v: &mut [T], is_less: &mut F)
             // fill the hole in `v` with `tmp`, thus ensuring that `v` still holds every object it
             // initially held exactly once.
             let mut hole = InsertionHole {
-                src: &mut tmp.value,
+                src: &mut *tmp,
                 dest: &mut v[1],
             };
             ptr::copy_nonoverlapping(&v[1], &mut v[0], 1);
 
             for i in 2..v.len() {
-                if !is_less(&v[i], &tmp.value) {
+                if !is_less(&v[i], &*tmp) {
                     break;
                 }
                 ptr::copy_nonoverlapping(&v[i], &mut v[i - 1], 1);
@@ -1587,12 +1600,6 @@ fn insert_head<T, F>(v: &mut [T], is_less: &mut F)
         }
     }
 
-    // Holds a value, but never drops it.
-    #[allow(unions_with_drop_fields)]
-    union NoDrop<T> {
-        value: T
-    }
-
     // When dropped, copies from `src` into `dest`.
     struct InsertionHole<T> {
         src: *mut T,