to be a multirange or not be, that's the question

Ok, subject was a bit philosophical but this message I just found is
quite confusing.

"""
regression=# select cast(null as anyrange) &> cast(null as anymultirange);
ERROR:  argument declared anymultirange is not a multirange type but type anymultirange
"""

-- 
Jaime Casanova
Director de Servicios Profesionales
SystemGuards - Consultores de PostgreSQL