def specialization_signature_string(fused_compound_type, fused_to_specific):
    """
    Return the signature for a specialization of a fused type. e.g.

        floating[:] ->
            'float' or 'double'

        cdef fused ft:
            float[:]
            double[:]

        ft ->
            'float[:]' or 'double[:]'

        integral func(floating) ->
            'int (*func)(float)' or ...
    """
    fused_types = fused_compound_type.get_fused_types()
    if len(fused_types) == 1:
        fused_type = fused_types[0]
    else:
        fused_type = fused_compound_type
    return fused_type.specialize(fused_to_specific).typeof_name()
