From a quick glance, it seems that this proposal includes anonymous structs/unions only within struct/union definitions, but not as types in general. Is there a deep reason for that? All things being equal, it seems nicer to expand the type grammar, such that this isn’t a special case within type definitions but instead just another kind of type. A closely-related pre-RFC seems to be doing just that.
(I haven’t thought deeply about the implications of any of this, but just wanted to note the general principle of not special-casing the type grammar.)