{"ast_node_type":"other","tokens":[{"end":70,"kind":"keyword","start":0,"text":"//"}]}
        // instead of having a `FnSig` and a `Option<CoroutineTypes>`,
        // FIXME: We could probably actually just unify this further --
        // we can have a `ClosureSignature { Coroutine { .. }, Closure { .. } }`,