{"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"//"}]}
        // `Fn > AsyncFn > FnMut > AsyncFnMut > FnOnce > AsyncFnOnce`
        // Though in the future, I'd like typeck to choose:
        // ...or *ideally*, we just have `LendingFn`/`LendingFnMut`, which