review comments on vec-insert-remove and vec-into-iter

src/vec-insert-remove.md

@@ -16,13 +16,14 @@ using the old len.
 pub fn insert(&mut self, index: usize, elem: T) {
     // Note: `<=` because it's valid to insert after everything
     // which would be equivalent to push.
-    assert!(self.len >= index, "index is out of bounds");
+    assert!(index <= self.len, "index out of bounds");
     if self.cap == self.len {
         self.grow();
     }
 
     unsafe {
         if index < self.len {
+            // ptr::copy(src, dest, len): "copy from source to dest len elems"
             ptr::copy(
                 self.ptr.as_ptr().offset(index as isize),
                 self.ptr.as_ptr().offset(index as isize + 1),
@@ -41,7 +42,7 @@ Remove behaves in the opposite manner. We need to shift all the elements from
 ```rust,ignore
 pub fn remove(&mut self, index: usize) -> T {
     // Note: `<` because it's *not* valid to remove after everything
-    assert!(self.len > index, "index is out of bounds");
+    assert!(index < self.len, "index out of bounds");
 
     unsafe {
         self.len -= 1;

src/vec-into-iter.md

@@ -133,8 +133,16 @@ impl<T> Drop for IntoIter<T> {
         if self.cap != 0 {
             // drop any remaining elements
             for _ in &mut *self {}
+
+            let align = mem::align_of::<T>();
+            let elem_size = mem::size_of::<T>();
+            let num_bytes = elem_size * self.cap;
+
             unsafe {
-                alloc::dealloc(self.buf.as_ptr() as *mut _, alloc::Layout::new::<T>());
+                alloc::dealloc(
+                    self.buf.as_ptr() as *mut _,
+                    alloc::Layout::from_size_align_unchecked(num_bytes, align),
+                );
             }
         }
     }