URIReferenceGrammar : is 0.0.0.7.free.fr a valid authority ?

Hi there, 
I've been URIReferenceGrammar.cpp to parse URL syntax, and I stumbled on this :

the parser considers '0.0.0.7.free.fr' as an invalid authority
yet, it says it is a valid reg_name

this seems to contradict the rules 
   authority     = [ userinfo "@" ] host [ ":" port ]
   host          = IP-literal / IPv4address / reg-name
