{"ast_node_type":"other","tokens":[{"end":66,"kind":"keyword","start":0,"text":"PatKind::Box(subpat)"}]}
                    PatKind::Box(subpat) | PatKind::Ref(subpat, _)
                    // FIXME: this doesn't work with recursive subpats (`&mut &mut <err>`)
                        if matches!(subpat.kind, PatKind::Err(_) | PatKind::Expr(_)) =>