if (!(node->parent == parent))
abort ();
if (!(node->branch_size
- == (node->left != NULL ? node->left->branch_size : 0)
- + 1 + (node->right != NULL ? node->right->branch_size : 0)))
+ == (node->left != NULL ? node->left->branch_size : 0)
+ + 1 + (node->right != NULL ? node->right->branch_size : 0)))
abort ();
if (!(balance >= -1 && balance <= 1))
abort ();