Diff Coverage

    source_is_dtensor = isinstance(source, DTensor)
    target_is_dtensor = isinstance(target, DTensor)
    if source_is_dtensor != target_is_dtensor:
        raise ValueError(
            "Tied parameters must both be DTensors or both be local Parameters: "
            f"{source_fqn}={type(source).__name__}, {target_fqn}={type(target).__name__}"
        )
    if not source_is_dtensor:

        )
    if not source_is_dtensor:
        return
    if source.device_mesh != target.device_mesh:
        raise ValueError(
            f"Tied DTensors must use the same device mesh: {source_fqn} and {target_fqn}"
        )
    if tuple(source.placements) != tuple(target.placements):
        raise ValueError(

        target,
    )
    _set_param_by_path(model, target_fqn, source)
    if _get_attr_by_path(model, target_fqn) is not source:
        raise ValueError(
            f"Failed to restore tied Parameter identity: {source_fqn} and {target_fqn}"
        )