let foo = {}
useEffect(() => {
foo.bar.baz = 43;
}, []);
This asks you to include foo.bar.baz into deps. But this doesn't make sense, as you write to it. Instead it should ask to include foo.bar into array.
If foo is a newly created object in render scope then we might additionally nudge you to useRef for it instead. Because otherwise it won't be shared between renders.