{"ast_node_type":"variable","tokens":[{"end":56,"kind":"keyword","start":0,"text":"let"}]}
    let v = s.do_stuff();         // no deref, no parens
    // `t.0` gets auto-refed -> no deref needed -> no parens
    let v = &s.do_stuff();        // `&` is for result -> no deref, no parens