{"ast_node_type":"other","tokens":[{"end":23,"kind":"keyword","start":0,"text":"//"}]}
    // Uses 0xFFFF_FFFF
    assert_eq!(size_of::<Option<Option<Option<Option<MyIdx>>>>>(), 4);
    assert_eq!(size_of::<Option<Option<Option<Option<Option<MyIdx>>>>>>(), 4);