{"ast_node_type":"other","tokens":[{"end":9,"kind":"keyword","start":0,"text":"{"}]}
        {
            && fields.iter().filter(|p| !matches!(p.ctor(), Constructor::Wildcard)).count() >= 2
            // Convert a `Union { a: p, b: q }` witness into `Union { a: p }` and `Union { b: q }`.