{"ast_node_type":"other","tokens":[{"end":54,"kind":"keyword","start":0,"text":"Some(ty::ClosureKind::FnOnce)"}]}
                    Some(ty::ClosureKind::FnOnce) => {
                    Some(kind @ (ty::ClosureKind::Fn | ty::ClosureKind::FnMut)) => kind,
                        bug!("closure kind does not match first argument type")