{"ast_node_type":"other","tokens":[{"end":103,"kind":"keyword","start":0,"text":"//"}]}
                            // (The rules for `DispatchFromDyn` ensure there's exactly one such field.)
                            // Not there yet, search for the only non-ZST field.
                            let (idx, _) = receiver.layout.non_1zst_field(self).expect(