message: more_renames
  Closes:
  Approved by: wqfish
diff: @@ -767,22 +767,18 @@ impl NaiveInternalNode {
  }
  }
  - fn node_for_subtree(
  - first_child_index: u8,
  - num_children: u8,
  - children: &Children,
  - ) -> BinaryTreeNode {
  - if num_children == 1 {
  + fn node_for_subtree(begin: u8, width: u8, children: &Children) -> BinaryTreeNode {
  + if width == 1 {
  return children
  - .get(&first_child_index.into())
  + .get(&begin.into())
  .map_or(BinaryTreeNode::Null, |child| {
  - BinaryTreeNode::new_child(first_child_index, &child)
  + BinaryTreeNode::new_child(begin, &child)
  });
  }
  - let half_size = num_children / 2;
  - let left = Self::node_for_subtree(first_child_index, half_size, children);
  - let right = Self::node_for_subtree(first_child_index + half_size, half_size, children);
  + let half_width = width / 2;
  + let left = Self::node_for_subtree(begin, half_width, children);
  + let right = Self::node_for_subtree(begin + half_width, half_width, children);
  match (&left, &right) {
  (BinaryTreeNode::Null, BinaryTreeNode::Null) => {
  @@ -797,7 +793,7 @@ impl NaiveInternalNode {
  _ => (),
  };
  - BinaryTreeNode::new_internal(first_child_index, num_children, left, right)
  + BinaryTreeNode::new_internal(begin, width, left, right)
  }
  fn get_child_with_siblings(
  