pub fn migrate_name(
name: &Name,
cursor: &IrCursor,
) -> Result<Name, MigrationDiagnostic>Expand description
Migrates one Classic name, refusing a Classic name that has no v4 spelling.
A v4 name is one or more non-empty segments, and every v4 reader refuses the empty string
where a name belongs. A Classic name with no words — or with nothing but empty words — has
nothing to encode, so it is refused here rather than written out as a "" that would produce
a v4 document no reader accepts. cursor is where the refusal is reported.