private static @Nullable ASTNode findAncestorChild(@NotNull ASTNode ancestor, @NotNull TreeChangeImpl change) {
    List<ASTNode> superParents = change.getSuperParents();
    int index = superParents.indexOf(ancestor);
    return index < 0 ? null :
           index == 0 ? change.getChangedParent() :
           superParents.get(index - 1);
  }
private static @Nullable ASTNode findAncestorChild(@NotNull ASTNode ancestor, @NotNull TreeChangeImpl change)