{"ast_node_type":"function","tokens":[{"end":90,"kind":"keyword","start":0,"text":"fn"}]}
fn try_and<T, E>(a: T, b: T, mut f: impl FnMut(T) -> Result<bool, E>) -> Result<bool, E> {
// `Ok(false) && Err(_) -> Ok(false)`
    let a = f(a);