`Eq` is an unnecessary bound here. `TreeMap` only requires `TotalOrd` (which as it happens includes `Eq` via `TotalEq`).

I'm not convinced that we need extra bounds (like `TotalOrd`) at all on unrelated traits, since you can't even construct a `TreeMap` without `TotalOrd`, but precedent so far is to use the "required" bounds on all traits. So `<K: TotalOrd + Show, V: Show>` should be correct.