Try to implement insert_slice

Author: nipunn1313

lib.rs

@@ -300,16 +300,27 @@ impl<A: Array> SmallVec<A> {
     }
 
     pub fn insert(&mut self, index: usize, element: A::Item) {
-        self.reserve(1);
+        let elements = [element];
+        self.insert_slice(index, &elements[..]);
+    }
+
+    pub fn insert_slice(&mut self, index: usize, slice: &[A::Item]) {
+        self.reserve(slice.len());
 
         let len = self.len;
         assert!(index <= len);
 
         unsafe {
+            let slice_ptr = slice.as_ptr();
             let ptr = self.as_mut_ptr().offset(index as isize);
-            ptr::copy(ptr, ptr.offset(1), len - index);
-            ptr::write(ptr, element);
-            self.set_len(len + 1);
+            ptr::copy(ptr, ptr.offset(slice.len() as isize), len - index);
+
+            // This does not give self ownership/reference to the element in slice. Thus elements
+            // of slice
+            // How to do that...
+            ptr::copy(slice_ptr, ptr, slice.len());
+
+            self.set_len(len + slice.len());
         }
     }
 }
@@ -855,6 +866,7 @@ pub mod tests {
         assert_eq!(*v.swap_remove(1), 1);
         assert_eq!(*v.remove(1), 3);
         v.insert(1, Box::new(3));
+        // This test fails because the Box<3> ref drops to 0 during the iteration below
 
         assert_eq!(&v.iter().map(|v| **v).collect::<Vec<_>>(), &[0, 3, 2]);
     }