def METHOD_NAME(path: str) -> None:
    """Track which actual files has been referenced either explicitly by a tentative path, or as
    a suggested rename."""
    if path in actual_dirs:
        referenced[path] = True
    else:
        dirname = os.path.dirname(path)
        refs = referenced.setdefault(dirname, set())
        if isinstance(refs, set):
            refs.add(path)
    # Recalculate possible matches, to avoid suggesting the same file twice.
    nonlocal actual_paths
    actual_paths = tuple(get_unreferenced(actual_files, actual_dirs))