Change:
assert_eq!(ip.is_multicast(), m_scope.is_some()); } <del> //    unspec loopbk uniqlo global unill  unisl  uniglo  doc    mscope check("::", true,  false, false, false,  false, false, false, false, None); check("::1", false, true,  false, false, false, false,  false, false, None); check("::0.0.0.2", </del> <ins> //    unspec loopbk uniqlo global unill  unisl  uniglo doc    mscope check("::", &[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], true,  false, false, false, false, false, false, false, None); check("::1", &[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1], false, true,  false, false, false, false, false, false, None); check("::0.0.0.2", &[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2], </ins> false, false, false, true,  false, false, true,  false, None); <del> check("1::", </del> <ins> check("1::", &[0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, false, true,  false, false, true,  false, None); <del> check("fc00::", </del> <ins> check("fc00::", &[0xfc, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, true,  false, false, false, false, false, None); <del> check("fdff:ffff::", </del> <ins> check("fdff:ffff::", &[0xfd, 0xff, 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, true,  false, false, false, false, false, None); <del> check("fe80:ffff::", </del> <ins> check("fe80:ffff::", &[0xfe, 0x80, 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, false, false, true,  false, false, false, None); <del> check("febf:ffff::", </del> <ins> check("febf:ffff::", &[0xfe, 0xbf, 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, false, false, true,  false, false, false, None); <del> check("fec0::", </del> <ins> check("fec0::", &[0xfe, 0xc0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, false, false, false, true,  false, false, None); <del> check("ff01::", </del> <ins> check("ff01::", &[0xff, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, false, false, false, false, false, false, Some(InterfaceLocal)); <del> check("ff02::", </del> <ins> check("ff02::", &[0xff, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, false, false, false, false, false, false, Some(LinkLocal)); <del> check("ff03::", </del> <ins> check("ff03::", &[0xff, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, false, false, false, false, false, false, Some(RealmLocal)); <del> check("ff04::", </del> <ins> check("ff04::", &[0xff, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, false, false, false, false, false, false, Some(AdminLocal)); <del> check("ff05::", </del> <ins> check("ff05::", &[0xff, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, false, false, false, false, false, false, Some(SiteLocal)); <del> check("ff08::", </del> <ins> check("ff08::", &[0xff, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, false, false, false, false, false, false, Some(OrganizationLocal)); <del> check("ff0e::", </del> <ins> check("ff0e::", &[0xff, 0xe, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], </ins> false, false, false, true,  false, false, false, false, Some(Global)); check("2001:db8:85a3::8a2e:370:7334", <ins> &[0x20, 1, 0xd, 0xb8, 0x85, 0xa3, 0, 0, 0, 0, 0x8a, 0x2e, 3, 0x70, 0x73, 0x34], </ins> false, false, false, false, false, false, false, true, None); <ins> check("102:304:506:708:90a:b0c:d0e:f10", &[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16], false, false, false, true,  false, false, true,  false, None); </ins> } #[test]

Discussion:
Tracking issue for First needs to be implemented, then go through an FCP! Looks like the is being implemented over at
This issue is now entering a cycle-long final comment period for stabilization
Discussed recently, the libs team decided to stabilize.