KeyDeserialize trait is private making custom keys and generics over keys not possible.

[0xekez]

The KeyDeserialize trait which is required for a type that would like to be a key for a Map is private in the cw_storage_plus::de module. This makes implementing custom map keys and functions that are generic over the map key type not possible.

For example, a generic function which lists all of the keys in a Map can't be implemented because the trait is private:

fn list_items<'a, K, V>(
    deps: Deps,
    map: Map<K, V>,
    start_at: Option<K>,
    limit: Option<u64>,
) -> StdResult<Vec<K>>
where
    K: cw_storage_plus::Bounder<'a>
        + cw_storage_plus::PrimaryKey<'a>
        + cw_storage_plus::de::KeyDeserialize,
    V: serde::de::DeserializeOwned + serde::Serialize,
{
    let items = map.keys(
        deps.storage,
        start_at.map(Bound::inclusive),
        None,
        cosmwasm_std::Order::Descending,
    );
    match limit {
        Some(limit) => Ok(items.take(limit as usize).collect::<Result<Vec<K>, _>>()?),
        None => Ok(items.collect::<Result<Vec<K>, _>>()?),
    }
}

Would be really cool to be able to do this. :)

[maurolacy]

Sure.

In the mean time, you can try removing that bound and using keys_raw instead, to list the raw keys.

I guess you know this already, but the approach you have regarding limit can be gas consuming, as there is no default / max limit.